Building notes by constructor pdf

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Assala mu alykum My Name is saqib imran and I am the
student of b.tech (civil) in sarhad univeristy of
science and technology peshawer.
I have written this notes by different websites and
some by self and prepare it for the student and also
for engineer who work on field to get some knowledge
from it.
I hope you all students may like it.
Remember me in your pray, allah bless me and all of
you friends.
If u have any confusion in this notes contact me on my
gmail id: Saqibimran43@gmail.com
or text me on 0341-7549889.
Saqib imran.

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Determine Effect of Trench Excavation on Nearby
Buildings by Rule of Thumb
Clearly, trench excavation affects nearby buildings and causing them to settle.
The major factors that cause building settlement are soil relaxation and
lowering groundwater. Both of these factors are triggered by the trench
excavation.
This articles presents the determination of trench excavation influence on
nearby buildings by rule of thumb.
Fig.1: Effect of trench excavation on nearby buildings
Trench excavation influence nearby buildings
because of two reasons which are:
 Soil relaxation due to excavation
 Groundwater lowering because of excavation
Soil relaxation due to excavation
When a trench excavated close to a building, soil relaxation and subsequent
settlement of the building is highly likely as shown in figure 1.

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Fig.2: settlement or failure of building foundation due to trench excavation
Therefore, it is necessary to provide adequate support for the trench to prevent
soil relaxation as illustrated in figure 2. Alternatively, excavate the trench away
from the foundation which may not be a valid option all the time.

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Fig.3:Support trench excavation to prevent soil movement
Moreover, a rule of thumb can be used to check whether the trench excavation
influences the nearby building or not. Draw a line with 2H:1V from the bottom
of the foundation as shown in figure 4. If the trench is within this line, then
engineer shall expect soil relaxation and eventual settlement of building
foundation.

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Fig.4: The building is within the line, prevent this condition
Finally, if the soil at project site is very loose sandy soil, then draw the line with
3H:1V rather than 2H:1V, as illustrated in figure 5.
Fig.5: line of checking the trench excavation affect on nearby building in very
loose sandy soil
Groundwater lowering because of excavation
By and large, groundwater moves and seeps into the excavation from the
surrounding areas of the trench. This will lower the level of ground water in the
trench vicinity area as illustrated in figure 6. Effective stresses increase as a
result of groundwater lowering and consequently the foundation suffer
settlement.

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Lastly, lowering ground water increases effective stress in clay layer shown in
figure 6, and greater effective stress causes foundation settlement.
Fig.6: Groundwater seeps into the excavation
Residential Buildings – Types and Site Selection for
Residential Building
What is a Residential Building?
A residential building is defined as the building which provides more than half of
its floor area for dwelling purposes. In other words, residential building provides
sleeping accommodation with or without cooking or dining or both facilities.
Types of Residential Buildings

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Residential buildings are divided into following types
 Individual houses or private dwellings
 Lodging or rooming houses
 Dormitories
 Apartments
 Hotels
Individual houses or Private dwellings
Individual houses or private dwellings are generally owned by members of a
single family only. If more than one family residing in that building then it is
called as multiple family private dwelling.

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Lodging or Rooming Houses
Lodging or rooming houses are multiple or group of buildings which come under
one management. In this case, Accommodation is provided for separately for
different individuals on temporary or permanent basis.
Dormitories
Dormitories are another type of residential buildings, in which sleeping
accommodation is provided together for different individuals. School hostels,
military barracks come under this category.

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Apartments
Apartments or flats are big buildings which consists separate dwellings for
different families. Apartment will resides minimum three or more families living
independently of each other.

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Hotels
Hotels are just like lodging houses and also managed by single management
but they provide accommodation primarily on temporary basis. inns, motels etc
come under this category.
Site Selection for Residential Buildings
Selection of site for any building is a very important and experts job and should
be done very very carefully by an experienced engineer. The requirements of
site for buildings with different occupancies are different.Following are some of
the important factors which should be considered while selecting site for any
residence.
1. The site should be in fully developed area or in the area which has
potential of development.
2. There should be good transport facilities such as railway, bus service,
for going to office, college, market, etc.
3. Civic services such as water supply, drainage sewers, electric lines,
telephone lines, etc. should be very near to the selected site so as to
obtain their services with no extra cost.
4. Soil at site should not be of made up type as far as possible. The
buildings constructed over such soils normally undergo differential

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settlement and sometimes become the cause of collapse. Cracks in
buildings in such conditions, are quite common
5. The selected site should be large enough; both to ensure the building
abundant light and air to prevent any over dominance by the
neighboring buildings.
6. The ground water table at the site should not be very high.
7. Nearness of schools, hospitals, market, etc. are considered good for
residential site but these facilities do not carry any significance in the
selection site for other public buildings.
8. Good foundation soil should be available at responsible depth. This
aspect saves quite a bit in the cost of the building.
9. The site should command a good view of landscape such a hill, river,
lake, etc.
10. Residential house site should be located away from the busy
commercial roads.
11. Residential site should not be located near workshops, factories,
because such locations are subjected to continuous noise.
12. Orientation of the site also has some bearing on its selection. Site
should be such in our country that early morning sun and late evening
sun is accepted in the building in summer and maximum sun light is
available in most of winter.
What are the Requirements of Partition Walls in
Buildings
There are several requirements that a partition wall need to meet otherwise its
purpose will be compromised.
So, it is necessary to understand partition wall requirements in order to build it
with high quality and provide satisfactory performance.
This article will shed light on the partition wall requirements briefly.

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Partition wall requirements are as follows:
 It shall have small thickness (thin). Thus, largest possible floor area is
being used.
 Partition wall need to provide sufficient privacy in rooms in such away
that occupants feel comfortable in terms of both sound and sight.
 It needs to be adequately rigid so as to be able to withstand vibrations
caused by loads.
 Materials used for the construction of partition wall shall be fairly light
in weight, uniform, sound, durable, and sound insulator. Fig.1 shows a
soundproof partition wall.
 The partition wall materials need to have fire resistance properties so
that the wall does not catch fire due to sudden short circuit or any
other factors that may cause fire. Fig.2 shows fire resistant partition
wall.
 The wall shall withstand heat, dampness, and fungus.
 ease of construction is another partition wall requirements.
 Partition walls are required to carry sanitary fittings and heavy fixtures
for example a piece of equipment or furniture that is fixed in position.
 It should be economical.
 Finally, the partition wall need to cohere the structural wall properly.

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Fig.1: Sound Proof partition wall; it withstand fire for an hour
Fig.2: Fire resistant partition wall
What is Artificial Stone? Its Types and Applications
What is artificial stone?

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Artificial stone, which is also called casted stone, is constructed from cement,
sand , and natural aggregate such as crushed stone. it is possible to provide
certain surface textures to artificial stones.
Sometimes, specific pigments used to achieve certain color. The addition of
pigments shall not exceed 15% by volume.
Artificial stone can be cast into complicated and considerably detailed forms and
various sizes can be manufactured. Added to that, it can be reinforced to
increase strength.
Finally, it is worth mentioning that artificial stones are casted easily and
economically.
Figure 1 Artificial Stone
Artificial Stone Mix Ratio
Generally, cement and aggregate are mixed in proportion 1:3.

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When artificial stones are selected for building
constructions?
Artificial stone or cast stone will be used for construction when cost effective
and durable natural stone cannot be achieved.
What are the types of artificial stones?
Different types of artificial stones along with their constituent materials and
applications will be discussed briefly.
Ransom stone
It is also called chemical stone which its compression strength is at least 32
MPa. Ransom stone is manufactured by blending silica soda with cement to
provide fancy and ornamental flooring.
Figure 2 Artificial Ransom Stone
Concrete block
Concrete blocks are used for the construction of steps, window, sills, and piers.
It is cased in the construction site.

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Artificial marble
It is constructed from Portland gypsum cement and sand using either precast or
cast in situ technique.
For precast production technique, the casted artificial marble will be stripped
from the mould after three days and then treated with liquid fluorite of
magnesia solution at the age of five days.
After that, the stone is washed and wrapped with paper for 24 hours and
treated again with the same solution, and it will be polished at the final stage at
the age of 30days.
For in situ construction method, layer of prepared mixture is placed on a
canvas, and the thickness of the layer shall be 1.5 mm greater than the
required thickness of the stone to be constructed. The surface of the laid layer
is rubbed and then polished properly.
Figure 3 Artificial Marble Stone

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Bituminous stone
It is produced by impregnation of granite and diorite with refined tar. Functions
of bituminous stone includes the provide wear, noise, and dust resistance stone
surface.
Victoria stone
It is a granite piece which its surface is hardened by submerged the stone in
silica soda for two months.
Garlic stone
Garlic stone, which is employed as a surface drains and flag stones, is produced
by mixing and casting Portland cement and iron slag.
Imperial stone
The procedure used to produce imperial artificial stone includes careful washing
of finely crushed granite, mixing granite with Portland cement, cast the mixture
into a favored form, and finally steam cure the casted imperial stone for twenty-
four hours.

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Figure 4 Artificial Imperial Stone
How to Prevent and Control Efflorescence Formation
on Masonry Structures?
Efflorescence is a white crystalline material that is formed as a result of water
evaporation from salt solution and left salts on the surface of masonry. It is
demonstrated that, efflorescence originated from cement-based mortar, grout
or concrete masonry from which salt solution moves to the brick surface.
Efflorescence is generally deteriorating aesthetic view of masonry wall.
That is why this article is dedicated to discuss the control and prevention of
efflorescence formation.

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Controlling Efflorescence Formation on
Masonry Structures
Strategies and practices used to control efflorescence include:
1. Material selection
2. Design and detailing
3. Construction practices
1. Material Selection for Efflorescence Control
The first step to prevent or decline efflorescence is the selection of materials
that has low potential to produce efflorescence. For example, it is recommended
to use cements with low alkali content since the possibility of efflorescence
formation increases with the increase of alkali content.

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Moreover, it is advised to specify potable water and clean and washed sand for
the production of grout or mortar mixtures. Furthermore, building trims for
instance copping, sills, and cops that manufactured from low salt content
materials shall be selected otherwise the likelihood of efflorescence formation
will increase.
Finally, materials can be tested to find out whether they potentially cause
efflorescence formation or not. Test methods used for assessment of masonry
materials include test method C 67 efflorescence test for brick; chemical
analysis of cements to determine water soluble alkali (Na2O K2O) content;
chemical analysis of hydrated lime to determine calcium sulfate content; and
chemical analysis of sand, water, admixtures and cleaning agents to determine
alkali, chloride, and sulfate content.
2. Design and Detailing
Generally, rainwater can ingress into all kinds of masonry walls to a certain
extent, but proper design and detailing can be employed to decline or eliminate
the water penetration which subsequently contribute to the prevention of
The design measures that recommended to avoid efflorescence formation
involves:
2.1 Watertight Below Grade Masonry
Commonly, groundwater contains sizable quantity of soluble salts that may
accumulate in masonry and cause efflorescence creation.
This source of efflorescence can be removed through watertight masonry below
grade in addition to install base flashing to discharge water out of the wall a few
courses of masonry above the grade.

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Finally, it is recommended to use grout or mortar to support base flashing below
the air space.
2.2 Flashing on trim
Trim materials are usually applied in locations which are considerably weak to
water ingression for example coping, caps, and sills under window.
These materials are possibly contains salt that increase the chance of
Therefore, flashings shall be employed to prevent capillary action and avoid the
contact between masonry and trim materials.
2.3 Air Space
The provision of air space between exterior walls and interior of masonry walls
plays significant role in reducing efflorescence formation.
There are number of function that air space plays for instance separation of
exterior wall from other elements of masonry wall, permits water to drain down
the back of the of the brick wythe, and impede the movement of salts from
backing material by separating the brick wythe from the materials containing
salt compounds. Lastly, for the air space to perform its duty properly, it should
be kept clean during construction.
2.4 Proper Detailing of Movement Joints
If the movement joints are adequately sized, located, and sealed, then water
penetration into the wall will be declined to a great extent.

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3. Construction Practices to Control
Efflorescence
Beneficial construction practices that lead to decrease efflorescence formation
are as follows:
3.1 Utilized Water
Water used for masonry construction shall be clean and free from salts.
3.2 Protection of materials during transportation and
progression of construction process
It is required to separate masonry units from dirt, contamination, groundwater,
snow, and rain water through suitable storing.
Added to that, these materials need to be covered during construction process
with watertight membranes to avoid wetting.
Finally, it is advised to protect all masonry materials during transportation when
there is a chance of contamination from road salts, fertilizers, and airborne
contaminants.
3.3 Filling Joints Adequately
Sufficient filling of joints such as head and bed mortar joints in solid unit
masonry, face shells head and bed joints in hollow unit masonry, and grapevine
mortar joints on the exterior face of the wall is considerably critical factors that
must be considered to eliminate efflorescence.
This is will create adequate bond between masonry units and prevent the
ingression of wind driven water into masonry walls.

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3.4 Covering unfinished brickwork
Covering partially completed masonry works with waterproofing membranes at
the end of each working day is a must.
If such measure is not considered, the masonry works may be subjected to
rainwater and saturated which takes long time to dry.
Consequently, the likelihood of efflorescence formation will increase.
Purposes and Levels of Protection of Blast Resistant
Design of Buildings
Different purposes of blast resistant design of building are to limit structural
collapse, maintain building envelope and minimizing flying debris. The different
levels of protection for blast resistant design of buildings are divided in two 4
categories which are discussed.
Purposes of Blast Resistant Design of
Buildings
The prime goal of blast resistant design of buildings is to reduce danger of
residents of injury and fatality to a certain degree and to limit the damages and
destructions while an explosion occurs.

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The following purposes are outlined for the building resistant design of
buildings:
1. Limit Structural Collapse
It is required to design all structural members in such a way that their
behaviors during explosions are consistent with the specified level of projection.
Moreover, if individual structural member suffered localized failure or plastic
hinges formed due to the influences of explosions, then it would be necessary to
evaluate the damaged condition of structural system to confirm that the global
stability of the structure is maintained.
2. Maintain Building Envelope
The building envelope may be maintained through proper design and detailing
of all exterior structural and nonstructural members and openings. The design

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and detailing shall reduce the possibility of a breach that may permit
overpressures from exterior explosive dangers to enter the building interior.
3. Minimizing Flying Debris
This goal can be realized by installing, designing, and detailing barriers,
landscaping features, site furnishings, and structural and nonstructural
elements involving exterior openings.
For example, doors and windows, and interior overhead mounted items in such
a manner that reduce the likelihood of creating dangerous secondary fragments
because of explosions.
Established Levels of Protection for Buildings
The level of required protection against blast is established for the structure or
part of the structure and for each specific member considering the use and
occupancy considerations.
There are four major level of protection which will be discussed below:
1. Level of Protection I (Very Low i.e. Collapse Prevention)
At this level of protection, the building shall be prevented from collapse and
surviving residents will be able to leave the area. However, the structure will
not be adequately safe for occupants to return and items inside the buildings
may not remain intact.
So, the structure is anticipated to suffer damages up to the onset of total
collapse, but the progressive collapse will not occur. Added to that, individual
structural members are likely to damage and produce debris. Doors are highly
likely to be forced out of their frames, but the level of hazard for glazing will be
very low according to the ASTM F1642.

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2. Level of Protection II (Low i.e. Life Safety)
At this level of protection, not only does the structure is prevented from failure
but also the life of residents will be safe. The occupants will be able to leave the
area safely and return to their property temporarily. The building is expected to
suffer damages to a degree that its repair will be costly.
Moreover, individual structural members will not experience failure but they will
undergo considerable permanent deflection to an extent that they cannot be
repaired economically
Furthermore, doors will be wedged into their frames and hence will not be
operable. Regarding items inside the building, they may be suitable to be
retrieved.
3. Level of Protection III (Medium i.e. Property Preservation)
The structure will be preserved at this level of protection, and occupants will be
able to evacuate and then return to their property after cleaning and repairing.

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Buildings are anticipated to experience damages, but they can be repaired
economically.
With regard to individual structural elements, they will experience large
permanent deflection but they can be repaired economically.
Nonetheless, it is desired to replace such structural members due to certain
reasons such as aesthetic appearance and economy. Finally, equipment inside
the building may operate partially and they may be impaired for a time.
4. Level of Protection IV (High i.e. Continuous Occupancy)
At this level of protection, occupants will be able to stay inside their property
without suffering and interruptions. The structure and its structural members
are expected to experience superficial damages. Added to that, structural
elements will not suffer visible damages and permanent deflections.

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At this level of protection, doors will be operable but fair force may be required
and glazing will be safe according to the ASTM F1642. Lastly, equipments inside
the building will remain completely operational.
What is Raised Floor System? Its Advantages and
Applications
What is raised floor system?
Elevated floor system, which is also termed as access floor system, is a raised
structural floor that is placed on a reinforced concrete slab.
The elevated floor system consists of a several panels, as shown in Figure-1,
which are installed on vertical adjustable pedestals as it can be noticed in
Figure-2. The pedestals are fixed on the concrete slab using suitable means for
instance adhesives or mechanical fixings.
Moreover, the gap between the elevated floor system and reinforced concrete
slab below can be varied and ranges from 7.62cm (3inches) to 121.92cm
(48inches) because the pedestals are adjustable.
Furthermore, the panel of raised floor system is composed of cement or wood
core clad in steel or aluminum and its size is 60.96cm by 60.96cm. Finally, the
panels are compatible with several flooring finishes for example vinyl, linoleum,
laminate, rubber, carpet and stone or ceramic tiles.

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Fig.1: Panel of Raised Floor System with their Adjustable Pedestals
Fig.2: Adjustable pedestals used to support panels of raised floor
system; Bolted Stringer (left) and Stringerless corner Lock
Areas Typically Most Suitable for Raised Floor
Systems
 Computer rooms and other information technology spaces.
 General open office areas.
 Training and conference areas.
 Exhibit spaces.
 Support spaces for offices, including electrical closets, fan rooms, etc.
 Clean rooms

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Areas Not Suitable for Raised Floor Systems
Slab on Grade Locations
Raised floor system is not suitable to be placed directly on the slab on grade.
This is because protection against heat, contaminant, and moisture that
transferred with soil, soil gas, and ground water cannot be achieved for long
period.
Toilets, Showers, Baths, Dishwashing and Other Wet Area
Plumbing fixtures are commonly installed in these areas which may leak and
lead to the corrosion and deterioration panels.
Kitchen and Food Preparation Areas
High humidity and possible spillage food and liquids and seepage make these
areas inappropriate for such types of floor system.

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Laboratories
The likelihood of chemical and biological spills in addition to moisture and
presence of plumbing make laboratory unsuitable for raised floor system.
Fire Stairs
Stair landings need interface with any adjacent raised floors as a flush condition
with the edge of the access floor well supported.
Mechanical Equipment Rooms
Examples of such rooms involve air handling equipment, chiller, and boiler. it
can be noticed from their names that these room have conditions in which
panels of raised floor system will deteriorate and damage.
Other areas include Central storage rooms and loading areas, trash
rooms, UPS, emergency generator, and similar rooms, and Child care.
Advantages of Raised Floor System
 This type of floor system tackles the problem of shear transfer across
the diaphragm
 Raised floor system are waterproofed
 It leads to reduction in the cost of construction in high seismic regions
 Raised floor system could serve as a high thermal mass base material
for radiant heat systems which are distributed by hot air or hot water.
So, Heating and cooling a building with a raised flooring system is
more efficient
 The concrete surface can be finished as a final floor finish as desired by
sealing, polishing, stamping, or staining. Consequently, the extra cost
of covering used for covering floors will no longer be needed
 Acoustic isolation is another advantages offered by raised floor system.

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 In high wind threat areas, elevated floor system will improve the
lateral resistance and durability of multistory building especially when
it combined with concrete roof system
 Fire is suppressed from floor to floor
Structural Conditions Requirements of Raised
Floor System
There are several structural conditions that raised floor system need to be met
the following minimum conditions otherwise it will not be utilized unless it is
specified in building specifications.
 It should be able to support 11.86KN/m2
 It is required to carry point load of 4KN
 Raised floor system need to withstand a minimum impact load of
2.25KN
 It should resist rolling load (1 wheel) of 2KN at 1000 passes and
Seismic Conditions Requirements of Raised Floor System
The specified raised floor system need to comply the following conditions (as
minimum):
 For seismic zone 3 and higher seismic zones, it is required to use bolts
for fixing pedestals. Commonly, manufacture specifies the suitability of
pedestal for seismic zones.
 It is required to use bracing for pedestals provided that their length is
greater than 30.48cm and used in seismic zone 3 and greater.
Acoustic and Vibration Considerations During Design and Construction
of Raised Floor System

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Impact sounds on floor panels generated by walking or rolling load may
necessitate damping of panels with cushions on pedestals. Hollow panels do not
show proper performance in this regard whereas panels with light concrete,
cementitious materials, or wood will perform satisfactorily.
Transmission of sounds under the floor from one space to another might occur.
In this case, the provision of sound transmission attenuation will be required of
partition system.
Vibration transmission is not dealt with neither by manufacturer nor design
criteria to attenuate vibration such as from machinery, transformers or other
sources. So, specialist should be called to tackle such problem.
Common Site Problems During Masonry Construction
Masonry structure is easy to design and construct, but various site issues may
occur such as incorrect mix proportions, use of unauthorized admixtures,
sulphate attack, freeze and thaw cycles and aesthetic failures.
Common Site Problems During Masonry
Construction
1. Incorrect Mix Proportions
Incorrect mortar mix proportions are mostly the use of less quantity of binder
materials than the required amount. This problem is reported to be come up
when materials are mixed at the construction site.
Commonly, applicable codes and construction documents emphasize on
measuring binder material either by weight or volume, but this measure is
mostly ignored when material blending is carried out on project site.

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Sometimes, number of shovels is used as a measuring technique, but this
practice is not accurate and lead to incorrect mix proportions. This problem
cannot be tackled unless all mix constituents are accurately measure.
2. Use of Unauthorized Admixtures
This problem is the reduction of mortar quality due to the addition of air
entraining admixture that take the form of domestic detergent or washing up
liquids. It is likely that the strength of mortar is compromised especially in bond
due to excessive air entraining.
The main motivation of adding air entrain admixture is that it improves mortar
plastic properties, and mortar utilization will be substantially eased. This
problem is usually encountered when materials are mixed on site.
3. Sulphate Attack
Sulphate attack occurs as result of the reaction between tricalcium present in
Portland cement and soluble sulphate which may come from various sources for
instance masonry units and grounds.
The reaction is expansive and the size of ettringite, which is produced because
of the reaction, is greater than of the reacted materials. Consequently, spalling,
degradation and finally failure could occur.
Therefore, it is necessary to take suitable measures to prevent sulphate attack.
This may be achieved through preventing sulphate to reach the mortar.
It is reported that, the number of masonry units contain large amount of
sulphate are reducing constantly. So, sulphates in the ground would be the
major problem and the contact between ground and mortar need to be
prevented. This can be achieved by practicing correct detailing of damp poof
courses and related details.

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Regarding exceptional situations, where sulphates occur in atmosphere and
masonry units, proper measure can be considered to decrease the possibility of
sulphate attack.
For example, proper designing of coping and overhangs to avoid saturations will
be offer great assistance, in addition to the provision of air entraining agent.
4. Freeze and Thaw Cycles
When masonry elements saturated with water and subject to cycles of freezing
and thawing, the masonry member may suffer degradation and subsequent
failure.
There are certain strategies used to protect masonry members from the effect
of freezing and thawing for example introduction of suitable damp proof courses
and copings.
Another effective technique is to use air entraining agent in mortar which
proven to be substantially advantageous. That is why most applicable codes
specify the use of air entraining agent to protect masonry construction form
both freezing and thawing cycles and sulfate attacks.

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Fig.: Effect of freezing and thawing cycles on masonry member
5. Aesthetic Failures
Aesthetic of masonry members does not affect its load carrying capacity but it is
crucial and need to be considered during design and construction.
The formation of widespread bloom or efflorescence is not acceptable by the
majority of clients. Therefore, it is required to take necessary action to prevent
it for example covering newly constructed masonry at the end of each day to
prevent saturation, otherwise masonry member will develop disfiguring stain
and hence aesthetic appearance will be compromised.
Another aesthetic problem will arise when hydrated Portland cement is not
protected since it remains highly soluble and saturation will cause leaching of
calcareous solution from the material.

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After water evaporated from this solution, solid material will set on the surface
of the unit and joints. Added to that, the leaching of calcareous solution may
lead to horizontal white stain formation.
Common Defects in Concrete Formwork Systems
Concrete formwork systems suffer from several deficiencies such as defects due
to imperfect design and construction practice, defects in foundation level of
formwork systems, defects in vertical support of formwork systems and defects
in horizontal support of formwork systems. These common defects are
discussed below.
Common Defects in Concrete Formwork
Systems
1. Formwork Defects due to Imperfect Design
and Construction Practice
 Too much tolerances in construction
 Inability to control vertical rate of concrete placement
 Inability to check the tightness of bolts and wedges before loading
formwork systems
 Insufficient allowance for uplift of concrete under inclined formwork
systems
 Different load distribution between two or more member that supposed
to support common loads
 Incorrect computation of stresses because of over simplification of
design assumptions
 Lack of required provision for the vibration effect on ties, struts,
braces, and wedges
 Failure to properly account for wind loads

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 Insufficient allowance for the influence of stresses generated by
temperature, prestressing, and moisture movements
2. Defects in Foundation Level of Formwork
Systems
 Sole plates are not leveled
 Crushing of sole plate because of insufficient distribution of loads form
horizontal and vertical members
 Poor load carrying capacity of the ground under sole plate
 Deterioration of load carrying capacity of the ground for instance
washing out ground

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 Deterioration of sole plates with time because of several factors for
example weather condition
3. Defects in Vertical Support of Formwork
Systems
 Lack of ties between standards at point of loading
 Supports are out of plumb
 Insufficient bracing to scaffold
 Bearing plates at the top and bottom of props are distorted
 Insufficient lateral ties, vertical and plan bracing
 Lack of rigidity of screw connection because of lack of bracing or over
extension
 Utilizing adjustable steel props with nails, mild steel bolts and
reinforcing bars instead of correct pins

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Fig.: Formwork for Beams and Slabs with Vertical Supports
4. Defects in Horizontal Support of Formwork
Systems
 Horizontal members are not centrally placed in forkheads
 Lack of staggering in timber bolted connection which may lead to split
out of the timber bolted connection
 Insufficient lateral and tensional bracing
 Inadequate support to prevent overturning of deep principal elements
since forkheads are frequently omitted
 Insufficient support to cantilevers
 Inadequate bearing area to vertical supports and underside of main
members lead to crushing
 Folding wedges cut to too coarse a taper, not properly cleated, cut
from wet material
Construction of Stone Masonry Footing
The construction of stones bonded together with mortar is called stone
masonry. Stone masonry footing is a structural foundation constructed to
support walls. Different aspect of stone masonry footing is discussed.
Purpose of Stone Masonry Footing
The purpose of stone masonry foundation is to support structural walls and
transfer load to the soil beneath it. It should serve its purpose without
settlement or sinking. The load exerted on stone masonry footing should be
vertical.

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Fig.1: Stone Masonry Footing
Construction of Stone Masonry Footing
Dimensions of Excavation for Stone Masonry
Footing
Prior to the construction of stone masonry footing, a trench with depth ranges
from 1m to 1.5 m should be excavated.

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The width of excavation would be controlled by amount of loads exerted on the
footing. So, the width of footing is specified based on the imposed loads and
properties of soil on which the footing is constructed.
Then, the soil at the bottom of the trench needs to be compacted properly. At
this stage, the excavation is ready for the construction of stone masonry
footing.
Fig.2: Trench excavated for stone masonry footing construction
Properties of Stones for Footing
Stones should possess the following properties otherwise they will be
disqualified for the construction of stone masonry footing:
 The stone should durable
 Free from cracks
 Free from cavity

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 It need to be hard and tough
Examples of stones which are desirable for stone masonry footing construction
include granite, hard laminated stand stone and limestone, and bluestone.
Desired Dimensions of Stones
 The thickness of stones should be one fourth of their width
 If it is possible, the width of each stone used for the construction of
footing first course should match the stone masonry footing width. If
such stones are not obtainable, then joints can be provided and it is
acceptable.
Preparation of Stones for Stone Masonry
Construction
Stones need to be adequately wetted before they are laid in the foundation. this
measure is considered to prevent water absorption which detrimentally affect
the mortar.

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Fig.3: Wetting stones for stone masonry footing construction
Concrete Mix Ratio used for Plain Concrete Bed
The plain concrete bed provided at the bottom of the foundation is made of one
part of cement four part of sand and eight parts of coarse aggregate. The
maximum size of the aggregate is 40mm.
Dimensions of Plain Concrete Bed
The plain concrete bed thickness ranges from 10cm to 15cm. The plain concrete
layer should extend about 15cm from the stone masonry foundation on each
side of bottom course. So, the width of plain concrete is 30cm wider than the
bottom course of stone masonry footing.
Fig.4: Plain concrete at the bottom of stone masonry footing
Mortar Ratio for Stone Masonry Footing
Mortar is used between joints of stones to create required bond between then
and seal the joint to avoid the penetration of water. The proportion of the
mortar is one portion of cement to six portions of sand.

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Stone Masonry Footing Construction Steps
 After the trench is dug and prepared, then a layer of plain concrete will
be poured at the bottom of the trench.
 After plain concrete bed is set, the construction of stone masonry
footing will begin with laying a layer of mortar on which first stone
masonry course will be installed.
 Stones should be placed close to each other and the maximum joint
between is 2 cm.
Fig.5: Filling joints between placed stones with mortar
 The face of stone should be arranged to stagger the joints
 Long vertical joints should be avoided since it would be weakness point
of the stone masonry footing.
 To improve strength of stone masonry footing, bond stones will be
placed at a specified spacing of 1m. This bond stones will run through
the thickness of stone masonry footing.

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Fig.6: Placing bond stones during the construction of stone masonry
footing
 If the thickness of stone masonry footing is large, then the length of
bond stone should be increased to achieve its objective. This can be
obtained by installing a set of two or more bond stones overlapping
each other.
 Heart stones, which are installed at the middle of stone masonry
footing, should be as close to each other as possible and smaller stone
sizes should be used to fill voids.
Then, heart stones and smaller stone sizes will be covered by mortar and
spaces should be filled with mortar to improve footing strength.

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Fig.7: Placement of heart stone in the stone masonry footing
Fig.8: Small sized stones are placed to fill voids

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Fig.9: Placement of mortar over a course of masonry footing to fill
spaces
Types of Defects in Timber as a Construction Material
There are various types of defects in timber as a construction material. These
defects in timber can be due to natural forces, fungi, insects and during
seasoning and conversion. Types of these defects in timber is discussed in
detail.
Trees gives us the timber which is converted into required form and finally
used. Before reaching this final stage, timber comes across many critical stages
like growing without defects, cutting at the right time, seasoning, converting
and using. Different types of defects occur in timber at these various stages.
Types of Defects in Timber as a Construction
Material
In general, the defects in timber are mainly due to:
1. Natural forces
2. Fungi
3. During Seasoning

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4. During conversion
5. Insects
Defects in Timber due to Natural Forces
1. Wind cracks
2. Shakes
3. Twisted fibers
4. Upsets
5. Rind galls
6. Burls
7. Water stain
8. Chemical stain
9. Dead wood
10. Knots
11. Coarse grain
12. Foxiness
13. Druxiness
14. Callus
1. Wind Cracks in Timber
If the wood is exposed continuously to the high-speed winds, the outer surface
shrinks and forms crack externally which are called wind cracks.

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2. Shakes in Timber
Shakes are nothing but cracks which separates the wood fibers partly or
completely. Different shakes are formed in different conditions as follows:
 Cup shakes are formed due to non-uniform growth of a tree or
excessive bending by cyclones or winds. In this case, the shakes
develop between annual rings and separates them partly.
 Heart shakes, the other type of shakes which develop in maturity
approaching trees whose inner part is under shrinkage. The shake
spread from pith to sap wood following the directions of medullary
rays.
 Ring shakes are similar to cup shakes, but they completely separate
the annual rings.
 Star shakes are formed due to extreme heat or severe frost action.
They develop wider cracks on the outside of timber from bark to the
sap wood.
 Radial shakes are developed radially from pith to the bark.
3. Twisted Fibers in Timbers
When the tree in its younger age is exposed to high speed winds, the fibers of
wood gets twisted. This type of wood is not suitable for sawing. So, this can be
used for making poles, posts etc.

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4. Upsets
Upsets, a defect of timber in which the fibers of wood are crushed and
compressed by fast blowing winds or inappropriate chopping of tree.
5. Rind Galls
Rind galls are curved swellings of trees which are formed at a point where a
branch of the tress is improperly removed or fell down.

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6. Burls
Burls are uneven projections on the body of tree during its growth. These are
mainly due to the effect of shocks and injuries received by the tree during its
young age.
7. Water Stain
When the wood is in contact with water for some time, the water will damage
the color of wood and forms a stain on its surface. This defect is called as water
stain.

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8. Chemical Stain
Chemical stain is formed on the wood by the action of any external chemical
agents like reaction by the gases present in atmosphere etc. The stain area gets
discolored in this defect.
9. Dead Wood
The wood obtained from the cutting of dead tree is light in weight and is
actually defected. It is reddish in color and its strength is very less.

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10. Knots in Timber
The central part or stem of a tree is majorly used in the conversion of timber.
Branches from the stem are removed and whole rounded stem is taken. But the
base of branches forms a mark on the stem which results dark colored stains on
the surface after conversion. This dark colored stains are due to the continuity
of wood fibers. These dark colored rings are known as knots.
11. Coarse Grain Defect in Timber
The age of tree can be known by the number of annual rings. For fast growing
trees, the gap between the annual rings is very large. This type of trees are
called as coarse grained tress and timber obtained from them is of less
strength.

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12. Timber Foxiness
When the timber is stored without proper ventilation, the trees growth near the
banks of water bodies and over matured trees may exhibit this type of defect.
Foxiness is generally indicated by red or yellow spots.
13. Druxiness
Druxiness is a defect of timber in which the top surface of timber indicates white
spots. These spots will give the access to fungi.

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14. Callus
The wound of the tree is covered by a soft skin which is called as callus.
Defects in Timber due to Fungi
1. Dry rot
2. Wet rot
3. Brown rot
4. White rot

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5. Blue stain
6. Heart rot
7. Sap stain
1. Dry Rot in Timber
Dry rot is caused by certain type of fungi which actually eats wood for their
living. They make food by converting timber into dry powder form. This occurs
mainly when there is no ventilation of air or if the wood improperly seasoned.
Absence of sunlight, dampness, presence of sap will increase the growth of dry
rot causing fungi. This can be prevented by using well-seasoned wood and also
by painting the timber surface with copper sulphate.
2. Wet Rot in Timber
Wet rot is caused by fungi which decomposes the timber and converts it into
grayish brown powder form. Wet rot causing fungi growths mainly when there is
alternate dry and wet conditions of timber.

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3. Brown Rot in Timber
The cellulose compounds of the wood are consumed by certain types of fungi
which then makes the wood brownish and this defect is called as brown rot.

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4. White Rot in Timber
Some types fungi attacks lignin of wood and leaves cellulose compounds hence
the wood will turn into white color which is called white rot.
5. Blue Stain in Timber
Blue stain is a defect caused by some kind of fungi which makes the timber
bluish in color.

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6. Heart Rot in Timber
Heart rot is caused in the trees when the heart wood is attacked by fungi
through its newly formed branch. This type of fungi makes the tree hollow by
consuming heart wood. This defect is known as heart rot.
7. Sap Stain in Timber
When the moisture content in the timber is more than 25%, some types of fungi
attacks the sap wood and makes it discolored. This type of defect is known as
sap stain.

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Defects in Timber During Seasoning
1. Bow
2. Cup
3. Check
4. Split
5. Twist
6. Honey combing
7. Case hardening
8. Collapse
9. Warp
10. Radial shakes
1. Bow
When the converted timber is stored for longer time, some timber planks may
have curve along its length which is known as Bow.

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2. Cup
If the timber planks are curved along its width then it is called Cupping of
timber.
3. Check
Check is formation of crack in the wood which will separate the wood fibers.
They are formed due to over seasoning of wood.

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4. Split
Split is formed when a check extends from one end to the other end which will
split the wood into number of pieces.
5. Twist
Twist is formed when the timber piece is spirally distorted along its length. It
looks like propeller blade after twisting.

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6. Honeycombing
Honey combing occur in the inner part of the timber which cannot be identified
by just seeing. This is mainly due to stresses developed during drying of timber.
7. Case Hardening
Case is nothing but the top surface of wood which dries rapidly during seasoning
but the inner part didn’t. Then this defect is called as case hardening.

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8. Collapse
During drying, some part of the wood may dry rapidly while some may not.
Because of this improper drying shrinkage of wood occurs which results the
defect called collapse.

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9. Warp
The loss of shape of wood due to stresses developed during drying is called
warping. Cupping bowing, twisting of wood come under warping.
10. Radial Shakes
Radial shakes are developed after the tree being felled down and exposed to
sun for seasoning. In this case, the cracks run radially from bark to the pith
through annual rings.
Defects in Timber During Conversion

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1. Diagonal grain
2. Torn grain
3. Chip mark
4. Wane
1. Diagonal Grain Defect in Timber
During conversion of timber different cutting saws are used. The cutting should
be done properly. If there is any improper cutting by saw then a diagonal grains
will appear.
2. Torn Grain
In the conversion many tools are used. If any of the tools or any other heavy
things are dropped accidently on the finished surface of timber it will cause
small depression which is called as torn grain.

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3. Chip Mark
When the timber is cut through planning machine the parts of machine may
form chip marks on it. Usually they are indicated by chips on the finished
surface.
4. Wane
The edge part of the timber log contains rounded edge on one side because of
its original rounded surface. This rounded edge is called wane.

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Defects in Timber due to Insects
1. Termites
2. Beetles
3. Marine borers
1. Termites in Timber
Termites also known as white ants which forms a colony inside the timber and
eat the core part of the timber rapidly. They do not disturb the outer layer of
timber so one cannot identified their presence. The trees in tropical and sub-
tropical regions are mostly affected by these termites.
However, some trees like teak, Sal etc. cannot be attacked by termites because
of the presence of termite preventing chemicals in their cellulose part.

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2. Beetles in Timber
Beetles are a type of insects which destroy the sap wood of the tree and makes
a tunnel like hole from the bark. Usually the diameter of hole is around 2 mm.
They convert sap wood into powder form and these holes are used by larvae of
these beetles. Almost all hardwood trees can be prone to damage by these
beetles.
3. Marine Borers in Timber
Marine borers are usually found near coastal areas. They do not consume wood
but they make large holes of diameter up to 25mm in the timber to live inside
it. They excavated up to 60mm deep in the wood. The wood attacked by marine
borers is of less strength and discolored. They can attack all types trees present
in their region.

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Storage of Cement – Precautions, Duration and Place
of Storage
Proper precautions for the storage of cement such as duration and place of
storage, arrangement, atmospheric moisture content etc. is necessary after the
process of manufacturing and before using it in the construction site.
Because the cement hygroscopic nature, the cement absorbs moisture from the
atmosphere very actively and hardens like stone which cannot be used for
constructional purpose. So, storage of cement should be done with care.

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Precautions for Proper Storage of Cement
Cement should not be stored normally. There are some precautions to be
considered in the storage of cement. Following are the different situations
against which precautions are to be taken:
1. Atmospheric moisture content
2. Duration of cement storage
3. Place of storage
4. Arranging cement bags
5. Withdrawal of cement bags
1. Moisture Content at Place of Storage
Moisture content or dampness is the main hazard for the cement. The moisture
present in the atmosphere is enough for the cement to become useless
material. The cement should be stored in such a way that it cannot expose to
the atmosphere. So, air tight bags are used to pack the cement.

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The absorption of moisture from atmosphere will also depends up on the quality
of cement. If the cement is finely grained and very good in quality, then it will
absorb moisture vigorously. Hence, extra care should be taken for this type of
cement and it is better use it in its fresh stage.
In any case if it is exposed to atmosphere, the present of moisture content is to
be tested. If the moisture content is more than 5% then it is not useful for the
construction.
2. Duration of Cement Storage
Time of storing is also a factor that affects the cement especially its strength.
Longer the time reduces the strength of cement. It is preferred that the cement
should not be stored for more than 3 months. However, if it is stored more than
3 months the strength of cement should be tested before using it.
The following table gives us the percentage reduction of strength of cement for
different time periods.
Period of storage Fresh stage 3 months 6 months 1 year 5 years

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% Reduction in strength at 28 days 0% 20% 30% 40% 50%
If the cement is stored for longer time and strength is found to be reduced,
then it is not good for construction. But however, it can be reactivated by
different methods like vibro grinding etc. vibro grinding improves fineness
quality of long period stored cement and make it fit for the constructional
purpose.
3. Place of Cement Storage
The bags of cement should not be stored in open places. Preferably specially
designed storage sheds are good for cement storage. They can be used for
longer periods.
The main purpose of special design is to provide waterproof floors, roofs and
walls. The floor of shed should be well above the ground level. Small windows
with air tight doors should be provided. Proper drainage should be provided
inside and outside the shed to drain water in any case.
In general, one bag of cement contains 50 kilograms of cement, 20 bags of
cement will require 1 cubic meter to store. Based on this the dimensions of
storage shed are designed.

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4. Arrangement of Cement Bags
A wooden platform of height 150 to 200 mm is prepared above the floor of
storage shed to avoid the direct contact between the floors and cement bags.
On the prepared wooden platform, the cement bags should be arranged one
above the other which forms stack of cement bags. Each stack should not
consist not more than 10 bags of cement. The stack should not touch the walls
of shed and it should be considerably 300 mm away from the external walls.
Each stack should be closely connected to avoid the circulation of air.
To prevent collapsing of high stacks, cross arrangement of bags one above the
other is preferable. All the stacks are covered with water proof layer for long
term protection. Passage width of 900mm to 1000mm is provided between the
stacks. The stack should consist same type of cement and for each stack date of
placing should be noted to know their period of storage.
5. Withdrawal of Cement Bags

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When the time of using arrives, Withdrawal of cement bags from stacks
happens. The cement bags should be taken out in such a way that the bag first
placed in storage shed should be withdrawal first.
18 Types of Fixtures and Fastenings for Doors and
Windows
Fixtures and fastenings are provided for doors and windows to provide
operating facilities, security for rooms and ease of opening and closing etc.
Different types of fixtures and fastenings such as, hinges, bolts, handles, locks
are available.
Types of Fixtures and Fastenings for Doors and
Windows
Hinges
Hinge is fixture which helps the door to rotate freely along its axis. There are so
many types of hinges are there which are as follows.

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1. Butt Hinge
This is the most common type of hinge used for doors and windows. It has two
flanges made of cast iron or steel. One flange is screwed to the door or window
and other one screwed to frame.
2. Back Flap Hinge
This are similar to butt hinges and used for thin doors. Back flap hinges have
wide flanges than butt hinges. They are fixed to the back side of door and
frame.

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3. Counter Flap Hinge
This hinge has two centers, and these can be folded back to back.
4. Parliamentary Hinge
When the opening is very small or narrow, then it is better to provide
parliamentary hinges to provide more space of opening as well as to avoid
obstruction while moving furniture etc.

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5. Spring Hinge
Spring hinges are used for swinging doors. The door is closed automatically due
to spring action in this case. Spring hinges are available as single acting and
double acting spring hinges.
6. Rising Butt Hinge

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It is similar to normal butt joint, but it has helical nickel joint in between flanges
which helps the door to raise vertically upwards when opened. This is useful for
the rooms having carpets etc. the raise may be about 10mm.
7. Garnet Hinge
It has Tw different shaped hinges. One is of long arm shaped which is fixed to
the door and another is of plate shaped which is fixed to the frame. This type of
hinge is used for battened or ledged doors.

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8. Strap Hinge
It is also used for battened and ledged doors and windows. It has two long arm
shaped flanges.
9. Pin Hinge
This type of hinge consist two flanges which are joined by pin. If the pin is
removed then we can separate the flanges. This is generally used for heavy
doors. Two flanges are separately fixed to the door and frame.

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10. Nar-Madi Hinge
This is also used for heavy doors, but it consists only one flange which is fixed
to the door. Pin is fixed to the frame to which flange is attached whenever is
needed.
Bolts
Door or window bolts are used to provide security for the rooms. Different types
of bolts are described below.
11. Hook and Eye Type Bolts

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This type of bolt is used to keep the windows shutter in required position when
it is opened. Hook is fixed to the shutter frame and eye is fixed to the window
rail.
12. Flush Bolt
In case of flush bolt the bolt flush is desired to keep with the face of the door.
13. Aldrop Bolt

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Aldrop bolt is olden type and most common type bolt. To lock this bolt pad locks
are used.
14. Barrel Bolt
To fix the back faces of doors barrel bolts are used. It contains socket and plate,
socket is fixed to the frame and plate is fixed to the back face of door.
15. Espagnalette Bolt
This is used for highly secured doors and casement windows which cannot be
reached easily.

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16. Hasp and Staple Bolt
This is also locked by using pad lock as aldrop bolt. Hasp is fixed to the door or
window while staple is fixed to frame.
17. Handles
Handles are used to open or close the door or windows. There are many types
of handles are available. Some of them are Bow type, Lever handle, Door
handle, Wardrobe handle Etc.

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18. Locks
Locks used for doors and windows are many types and some of them are
padlock, mortise lock, rim lock, cupboard lock and lever handle lock etc.

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Materials and Methods of Thermal Insulation of
Buildings
What is Thermal Insulation of Buildings?
In general, people living in hot regions wants to make their inside atmosphere
very cool similarly people living in cold regions, wants warmer atmosphere
inside. But, we know that the heat transfer takes place from hotter to colder
areas. As a result, heat loss happens. To overcome this loss in buildings thermal
insulation is provided to maintain required temperature inside the building. The
aim of thermal insulation is to minimize the heat transfer between outside and
inside of building.

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Materials and Methods of Thermal Insulation of
Buildings
There are many forms of thermal insulation materials are available in the
market as follows:
1. Slab or block insulation
2. Blanket insulation
3. Loose fill insulation
4. Bat insulating materials
5. Insulating boards
6. Reflective sheet materials
7. Lightweight materials
1. Slab or Block Insulation
The blocks are made of mineral wool, cork board, cellular glass, and cellular
rubber or saw dust etc. These are fixed to the walls and roofs to prevent heat
loss and maintains required temperature. These boards are available in
60cmx120cm (or more area) with 2.5cm thickness.

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2. Blanket Insulation
Blanket insulation materials are available in blanket shape or like paper rolls
which are directly spread over the wall or ceilings. They are flexible and having
a thickness about 12 to 80mm. these blankets are made of animal hair or
cotton or wood fibers etc..
3. Loose Fill Insulation
Stud space is provided in wall where windows and doors are to be provided. In
that studding space of wall loose fill of some insulating materials is provided.
The materials are rock wool, wood fiber wool, cellulose etc.
4. Bat Insulating Materials
These are also available as blanket rolls but bat insulating rolls are having more
thickness than blanket type materials. These are also spreader over the walls or
ceilings.

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5. Insulating Boards
Insulating boards are made from pulp of wood, cane or other materials. These
pulp is pressed hard with some stress at suitable temperature to make it as a
solid boards. They are available in many sizes in the market. And these are
generally provided for interior lining of walls as well as for partition walls.
6. Reflective Sheet Materials
Reflective sheet materials like aluminum sheets, gypsum boards, steel sheet
Materials will have more reflectivity and low emissivity. So, these materials are
having high heat resistance. The heat gets reduced when solar energy strike
and gets reflected. These are fixed outside of the structure to stop the heat
entrance into the building.

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7. Lightweight Materials
By using light weight aggregates while preparing concrete mixture will also
results good results in heat loss preventions. Concrete will have more heat
resistance if it is made of light weight aggregates like blast furnace slag,
vermiculite, burnt clay aggregates etc.
Other General Methods of Building Thermal
Insulation
Without using any thermal insulating materials as said above we can achieve
the thermal insulation from the following methods.
 By providing roof shading
 By proper height of ceiling

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 Orientation of building
8. By Providing Roof Shading
By providing roof shading for the building at the place where sun directly strikes
the building during peak hours, we can reduce the heat by shading of roof.
Accurate angle should be provided for shading to prevent from sun light.
9. By Proper Height of Ceiling
The heat gets absorbed by the ceiling and emitted downwards that is into the
building. But, the point should be noted is, the vertical gradient of radiation
intensity is not significant beyond 1 to 1.3 m. it means it can travel up to 1 to
1.3 m downward from the ceiling. So, provision of ceiling at 1 to 1.3m height
from the height of occupant will reduce some heat loss.
10. Orientation of Building
The building orientation with respect to sun is an important thing. So, the
building should be constructed in an orientation in such a way that it shouldn’t
subject to more heat losses.
24 Different Components used for Pitched Roof
Construction
What is Pitched Roof?
Pitched roof is a type of roof which is provided with some slope as structure
covering. We know that the roofs are generally provided at top to cover and
protect the structure from different weather conditions. Pitched roofs are

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generally used where rainfall is heavy. If buildings are constructed with some
limited width, then also we can go for pitched roofs.
Components or Elements of Pitched Roofs
Following are the elements of pitched roofs:
1. Span
Span of roof is the clear distance between the two supports on which roof is
positioned by some other elements.
2. Ridge
The apex of the angle which is developed at top by the inclined surfaces at the
top of slope.
3. Rise

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The vertical distance or height of top of ridge from wall plate is called as rise.
4. Wall plates
Wall plates are provided at top of wall or supports. And these are generally
made of wood and are used to fix the common rafters.
5. Pitch
Pitch is nothing but slope of roof with the horizontal plane and is calculated as
the ration of rise to span.
6. Eaves
The bottom edge of sloped roof surface is called as eaves from which rain water
is drops down during raining.
7. Hip
Hip is a place where two sloping surfaces meet, where exterior angle is more
than 180o
.
8. Hipped end
At the end of a roof sloped triangular surface is formed which is called as hipped
end.
9. Valley

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It is also a place where two sloping surfaces intersects but the exterior angle is
less than 180.
10. Verge
Verge is the edge of gable roof which runs between ridge and eaves.
11. Ridge board
Ridge board is a wooden member which is provided long the ridge lie or apex of
the roof. Common rafters are supported by this ridge board. This is also called
as ridge beam or ridge piece.
12. Common Rafters
Common rafters are wooden members fixed to the ridge board perpendicularly.
They run from ridge to the eaves. These are fixed to the purlins at intermediate
points. Batten or boarding’s are supported by this rafter. In general, the spacing
between rafters is 30 to 45 cm.

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13. Purlins
Purlins are wooden or steel members supported by truss or wall. If the span is
large they are used to support the common rafters.
14. Hip rafters
These rafters are provided at the hip end. And they run diagonally from ridge to
the corners of the wall.
15. Valley rafters
Valley rafters run diagonally from ridge to the eaves. They are provided in
sloping positions to bear support valley gutters. The ends of purlins and jack
rafters will receive by the valley rafters.
16. Jack rafters
The rafters run from hip to the valley are called as jack rafters and usually they
are short in length.
17. Eaves board
The ends of lower most roof covering materials are rests on eaves board. It is
made of wood and usually 25mm x 25mm thickness and width. It is placed at
the feet of common rafters.
18. Barge board

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To hold the verge formed by the common rafters a wooden board is used which
is called as barge board.
19. Post plate
Post plate is similar to wall plate. Post plates are parallel to the face of the wall
and run continuous. Post plates provide support for the rafters.
20. Battens
Battens are usually made of wood and they are nailed to the rafters to give
supports for the roof covering material.
21. Template
Template is a masonry block made of concrete or stone which is placed under
the truss to provide larger load area of the wall.
22. Boarding’s
Boarding’s are similar to battens and these are also used to give support for the
roof covering material by nailing them to the rafters.
23. Truss
Truss is frame which consists of triangles and designed to support the roof tops.
24. Cleats

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To support the purlins, short sections of steel or wood are fixed to the rafters
and these sections are called as Cleats.
Methods to Rectify Over Leaned Buildings and
Structures
There are number of factors that cause the structure to excessively lean or
settle. For example, liquefaction of soil beneath the foundation after earthquake
occurrence, excavation, groundwater condition variation, poor soil bearing
capacity, inappropriate foundation and construction defects.
When a building over leaned or settled, then it is necessary to uplift it properly
to regain required safety and prevent undesired consequences. Building
rectification techniques are used to uplift such structures. These methods will be
discussed in the following sections.

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Fig.1: Over Tilting of Several Buildings and Towers in the World
Methods to Rectify Over Leaned Buildings and
Structures
Rectification methods used to uplift over tilted buildings include:
1. Compaction grouting method
2. Chemical grouting method
3. Underpinning method
4. Micro-Tunneling method
1. Compaction Grouting Method
It is one of the methods used to rectify buildings that tilted or settled
excessively.
Compaction grouting technique needs detailed preparation and plan prior to the
beginning of the work.
For example, it is required to determine grouting pressure, grouting depth,
grouting rate, configurations of grouting stations, and the method used to
execute the task.
It is necessary to equip the structure with adequate number of monitoring
devices. This is to observe the process and makes suitable changes during
lifting operation if it is needed.
There are two methods used for compaction grouting including drilling holes
through floor slab of the building vertically and perform the work or dug holes
at a specified degree from the side of the structure.

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Fig.2: Rectification of Tilted Building
It should be known that the function of the structure may be disrupted or
stopped when compaction grouting is conducted through holes dug through the
floor, but its effect is great. However, the latter technique will not influence
building functionality, but it is less effective compared with former technique.
It is recommended to concentrate grouting stations on the largest settled
locations and major grouting points should be arranged at the greatest depth.

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Fig.3: Grouting positions of compaction grouting technique, numbers
show the sequence of grouting
Regarding minor grouting points, they are aimed at smaller settled locations
and their depth is smaller.
Finally, the process of grouting is begun from the major points configured at
largest settled area and then minor points close to the major stations. If the
settlement is large, then the process may be conducted in more than one stage.
2. Chemical Grouting Method
Chemical grouting is another technique used to restore tilted building to its
original position. This method is economical but grouting process requires
substantial care to achieve the desired outcome.
If chemical grouting is not carried out properly, unanticipated grout flow may
occur and may lead to pipe and structural damages and decline grouting affect.
Similar to compaction grouting, it is necessary to establish detailed plan
grouting pressure, injection point configuration, techniques to prevent the
disappearance of grouting flow before the grouting process is started.
The determination of injection point arrangement, amount of injected grouting,
and grouting pressure is based on the experience and observation obtained
from devices placed on the structure.
Regarding methods used for prevention of grout fugacious flowing, either sheet
piles placed within grouting range or grouting setting time reduction is
employed.

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Fig.4: Chemical Grouting
3. Underpinning Method
Underpinning technique used to restore verticality of tilted structures. It is more
expensive compare with other aforementioned methods. Moreover, this
technique can be used to rectify structures that constructed on individual
footing and mat foundation.
Furthermore, underpinning method lacks those disadvantages that encountered
when compaction grouting or chemical grouting is employed. For example,
grout flowing to location which is not planned and predicted, and improper
uplifting or columns which is possible in the case of chemical and compaction
grouting.
Underpinning method procedure involves excavate working place, for
underpinning pile construction, around the foundation and then set jacks
between the foundation and pile cap to uplift the structure, and lastly carry out
load transfer operation.

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As far as disadvantages of underpinning are concerned, poor design of
underpinning may lead to increase the settlement of the structure.
Fig.5: Using underpinning method to restore building tilt
4. Micro-Tunneling Method
This method is used for structures which is built on cohesive soil and suffered
from limited leaning. In this case, it might be more feasible to create
deformations under less settled side of the structure using micro tunnels.
The procedure includes application of micro tunneling for drilling unsupported
small holes under less settled side of the structure, then these holes would be
deformed due to load of the structure and additional loads imposed to deform
small holes.

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When these holes are collapsed under structural load and additional load, a
sliding surface would be produced, and the foundation would rotate opposite the
direction of inclination.
Fig.6: Micro tunneling method used to restore tilt building to its original
location
Why is Timber Construction Popular in 21st Century?
Timber is a favorite construction material from the historic time and now, one of
the favorite construction material of the future. Timber construction material
when compared with other construction material gain:
 High Insulation property
 The carbon-dioxide emission is less
 Highly sustainable material
Sustainability is explained in terms of pollution and emission caused, which is
less compared to other materials. If we consider the amount of trees used for
this purpose, the sustainability is less.

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Why is Timber Construction Popular in
21st
Century?
There are many specific reasons inbuilt in timber material that made it to be
demanded greatly in 21st
century. It is studied from the research that a
percentage of 70% of new houses are made out of timber. These records for
25% of total construction. This percentage is said to increase in the future.
Some of the root causes behind the regain of timber construction popularity are
mentioned below:
1. The Invention of Cross Laminated Timber (CLT)
The development of cross laminated timber has greatly influenced the
popularity of timber for use in construction. This is not a material great enough
to compete with concrete or steel, but this has taken some role in people’s mind
to choose them over other construction material.
The CLT material is a combination of layered wood forms. These are combined
together with the help of glue and finally pressed to become monolithic. All
small forms of timber materials can be collected and combined together to form
large construction material of required size.
The CLT material is light and highly stable in nature. This material strength is
comparable with the strength of the steel and the brick. In London, the
researchers name it as the “new concrete”.

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2. Prefabricated Home Construction
Homes that are manufactured and modular in nature are categorized as
prefabricated homes. The timber with its high insulating property and low
energy consumption prove as a good prefabricated material.
Timber prefabricated homes are highly insulated for heat and sound with energy
efficiency more than 50%. This efficiency is greater than that attained from a
traditional house construction.
3. Speed of Timber Construction
As mentioned before, the CLT have brought a new picture for timber
construction. The use of CLT increased the speed of construction. The time
taken to construct the timber homes is very faster compared with the traditional
house construction.
Initially timber frames are constructed in its dry state. The dry plasterboards
can be used as walls which helps in the stabilization of moisture adaptation.

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4. Cost of Timber Construction
Timber is less costly compared with steel frame construction but costlier than
brick construction. Other benefits are that the timber is more durable and the
maintenance required for the same is less.
5. Strength of Timber Construction
Steel when compared with timber is light and stronger in construction. But
special studies on timber and the development of CLTs have proven this as a
material with higher strength and stability. Its proven characteristics have made
its application on high rise construction.
The Bridport House in London is an example of cross laminated timber high rise
project. This is an eight-storey building and 5 storey building combination.

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6. Insulation Properties of Timber Construction
Timber acts as an external cladding for preventing sound and heat with great
thermal efficiency. The timber provided can be less than 5cm thick which is
lesser than the thickness of the masonry provided. This low thickness is enough
for providing the thermal efficiency as the insulation properties is derived from
the interior of the wood.
The heat transfer in timber is very low when compared with other materials like
steel. Timber homes save money in our energy bill.
7. Environmental Impact from Timber Construction
The timber construction has great importance for being environmental friendly
as the material is a renewable source. The steel when compared with timber is
a great source of pollution. Timber construction is hence a great promoter of
zero carbon housing systems.

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Strategies to Protect Buildings Close to Deep
Excavation
Building structures close to the excavation for deep foundations may suffer
settlement and subsequent cracking and even failure. Therefore, it is necessary
to practice utmost cares while deep excavation is carried out to reduce its
undesired effect on the surrounding buildings.
Measures considered to protect buildings near deep foundation are discussed.
Fig.1: Structures Close to Deep Excavation
Strategies to Protect Buildings Close to Deep
Excavation
1. Building protection using the characteristics of excavation induced
deformation
o Reduce the unsupported length of the retaining wall
o Decrease the influence of creep

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o Take the advantage of corner affect
2. Building protection by increasing stiffness of the retaining-strut system
3. Building protection by utilizing auxiliary methods
1. Building Protection Using the Characteristics
of Excavation Induced Deformation
1.1 Reduce the Unsupported Length of the Retaining Wall
When retaining wall used as a safety measure for deep excavations, struts are
provided at a designated level to support the retaining wall. It is observed that,
the unsupported height as shown in Figure 2 of the retaining wall affects its
deformation due to earth pressure.
As the unsupported retaining wall length is decreased, the amount of
deformation will reduce as well and vice versa.

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Fig.2: Deep excavation with retaining wall and strut level, unsupported
length specified in figure left for each excavation stage
The unsupported height of retaining wall can be decreased by placing struts
close to the excavation level. The closer the struts to the ground level the lesser
the unsupported length as explained in Figure 3.
Finally, it is recommended to consider 0.5m distance between strut and ground
level at each excavation stage.
Fig.3: Deformation in figure A is less than that of figure B since
supported length smaller in figure. The only difference between figure
A and B is the distance of strut from ground level which 0.5m in figure
A and 1.5m in figure B

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1.2 Decrease the Influence of Creep
Creep is the increase of deformation with time under constant stress. it occurs
in clay soil. So, to decrease the affect of creep on the excavation, it is advised
to install struts as soon as the excavation stage is completed.
Usually, strut installation could take time and creep effect may increase and
worsen the condition of excavation. Therefore, it is recommended to lay 100mm
concrete on the excavation surface to contain the effect of creep till struts are
installed.
1.3 Take the Advantage of Corner Effect
When diaphragm walls are used to contain earth pressure in excavation,
deformation and settlement will commonly lesser at corners and short direction
of the excavation area compare with long direction.
So, if buildings are located at corners or along short direction of the excavation
area, then it is recommended to employ diaphragm walls to take advantage of
corner affects.

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Fig.4: Taking the advantages of corner effect to decrease effect of
foundation on adjacent buildings
2. Building Protection by Increasing Stiffness of
the Retaining-Strut System
The increase of retaining-strut system would help in the decrease of excavation
wall deformation and subsequently protect neighboring buildings.
Techniques used to increase retaining-strut system stiffness include declining
vertical and horizontal span of struts, increase retaining wall thickness, and
increase strut stiffness.
Reduction of vertical span of struts is proven to be the most effective stiffness
improvement technique because it reduces deformation considerably. This
technique would increase the rigidity of the system substantially and decline
deformation effectively.
It is demonstrated that, the increase of retaining wall thickness would not
contribute that much in reducing deformation. Finally, increasing strut stiffness
could reduce deformation. However, if it already has large stiffness, then
increase of strut stiffness will not be an option. So, reducing horizontal or
vertical span can be considered.
3. Building Protection by Utilizing Auxiliary
Methods
The purpose of auxiliary technique application is to either decrease settlement
or wall deformation.

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Any auxiliary techniques that lead to settlement or deformation reduction are
acceptable to be applied. However, these approached need to be assessed prior
to their application to find out their effects. This is because some of these
methods may not offer desired affect and in fact the condition might be
worsening in addition to the cost.
Different auxiliary methods include ground improvement, Counterfort walls,
Cross walls, Micro piles, and Underpinning.
Design and Construction Requirements for Flood
Prone Building Structures
Design and construction requirements such as elevation of structure,
foundations, anchorage and connections, use of fill and other factors for flood
resistant building structures are discussed.

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Fig.: Foundation of Flood Resistant Building Structure
Design and Construction of Flood Prone
Building Structures
Elevation of Structure
Significant flood resistant improvement can be obtained if the structure has the
lowest floors elevated to design flood elevation. Design flood elevation includes
wave height relative to a datum determined based on the flood hazard map of
the area.

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Fig.: Specified Flood Datum
Parking garages, buildings access, and storages are permitted to be constructed
below design flood elevation if the enclosed area reach the conditions of
enclosed areas applicable to specific flood hazard area.
Lastly, nonresidential structures and nonresidential portion of mixed use
structure are permitted to have lowest floor below design flood elevation
provided that they meet requirements of dry flood proofing. The dry flood
proofing is a combination of measured that makes structures waterproofing.
Fig.: Structure Elevated to be Flood Resistant

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Foundation Requirements of Flood Resistant Structures
The foundation of flood resistant structures needs to be designed and
constructed in such a way that withstands design flood circumstances. It should
have adequate capacity to resist flotation, collapse, and permanent lateral
movement under the critical load combinations that provided by ASCE 7.
Furthermore, the foundation design of flood resistant structures should depend
on the geotechnical characteristics of soil and strata beneath the foundation and
on the soil foundation interaction.
Added to that, it should take reduced structural capacity and instability due to
expansion, consolidation, liquefaction, local scour, subsidence, and erosion into
account if such incidents are expected to be occurred.
Regarding foundation depth, it is specified based on the geotechnical
consideration. It needs to meet foundation requirements that described above.
As far as foundation walk is concerned, it must withstand flood borne debris
impact, hydrodynamic, hydrostatic, wind, soil, and other lateral load that may
be imposed during flood design condition.
Apart from lateral loads, foundation wall shall be designed and constructed to
support buoyancy and vertical loads that imposed during design load conditions.
Regarding piers, piles, and columns, they are used to raise the structure above
design flood elevation in addition to meet requirements of the foundation of
flood resistant structure.

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Use of Filling Materials
When fill is used, it should be designed and constructed to withstand flooding
conditions for instance scour and erosion due to floods, quick rise and
drawdown of flood water, and prolonged inundation.
Fill used in flood hazard areas apart from high risk hazard area is allowed unless
it is leads to increase flood level while base flood discharge is occurred and it
declines flood way conveyance.
Lastly, fill is permitted to be used in high risk hazard flood area if it is not cause
wave run up, ramping, or deflection of flood water that damage the structure.
Anchorage and Connections
Anchorages and connections in the structures need to be designed and executed
to withstand the influence of vertical loads, uplift forces, and lateral loads.

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Beams shall be connected to piles, columns, piers, and foundation walls
adequately using suitable means such as bolts and welds.
Sufficient anchorages need to be installed for storage tanks, sealed conduits
and pipes, and other structures that may suffer from lateral movement and
floatation during design flood condition.
Other Factors for Flood Resistant Building Structures
Other factors that need to be accounted for during the design and construction
of flood resistant structures include use of flood resistant damage materials,
flood proofing, means of egress, utilities, and adverse impact to surrounding
structures.
Landings in Stairs – Purpose, Location and Standard
Dimensions
What is a Stair Landing?
Landings in a stair is a level floor or platform constructed at a location where
the direction of stairs changes, between flights of the stair, or at the top of stair
flight.
The locations of landings in a stair is shown in Figure 1, Figure 2 and Figure 3.

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Fig.1: Landing is provided when the direction of stair changes
Fig.2: Landing is provided between flights of a stair

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Fig.3: Stair landing at the top between and bottom of stair flights
What is the Purpose of Stair Landing?
 Stair landing is provided to permits stairs to change directions, Figure
4.
 Another purpose of stair landing provision is to allow occupants to rest.
Fig.4: Landing provided to allow stairway to change its direction

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What are the cases in which stair landings are
needed?
 Stair landing should be provided at the top and bottom of each flight of
exterior and interior stairs.
 Stair landing is needed where a doorway at the top of stair flight
swings toward the stair, Figure 5 and Figure 6.
 For stairways with straight run that have an overall rise greater than
3.65m, an intermediate landing should be provided.
Fig.5: Doorway swing on landing of stairway

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Fig.6: Doorway opens on toward the stairway
What the cases in which stair landing can be
omitted?
 If a doorway that located at the top of a stair in a dwelling unit is swing
away from the stair, then landing is not required between the stair and
the door.
 It is possible to omit landing at the top of a stair serving a secondary
entrance to a single dwelling unit provided that the stair does not have

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more than three rises and the door is sliding or swing away from the
stair.
 Landing stair can be neglected at the bottom of an exterior stair
provided that there are no obstruction within a lesser of stair width or
900mm for stair serving single unit and 1100mm for stair not serving a
single dwelling unit.
What are the standard dimensions of stair
landing?
 The width of landing should not be smaller than the width of stairway
they serve as illustrated in Figure 7.
Fig.7: Width of landing determined based on the stairway they serve
 The dimension of landing in the direction of travelling should be at
least equal to the width of the stair and it should not surpass 1219mm
where the stairway is a straight run.
 When a door is opened on the landing, it should not reduce the landing
smaller than half of required width. Added to that, when the door is

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opened completely, it should not project greater than 178mm on the
landing.
 If wheelchair spaces are required on stairway landing, it should not be
located with the required dimension of the landing and doors must not
swing over the wheelchair space.
Types of Failures Experienced by Different
Construction Materials Used in Structures
Types of failures experienced in different structure is greatly influenced by the
type of construction material used. The resisting capability of steel structure to
a particular load action is not similar to that of a concrete structure for the same
load conditions.
Types of failures experienced by different construction material in a structure,
their causes and details are discussed in this article.
Types of Failures Experienced by Different
Construction Materials
Failure Caused by Steel as a Construction Material
The different features of steel material i.e. the chemical composition, heat
treatments, rolling processes and other manufacture techniques employed
govern the mechanical properties of steel. Steel of same grade may show
different values or results which is dependent on the rate of loading of the steel
specimen, the temperature at which the test is carried out, the geometry of the
specimen and the condition of the specimen.
Easy study of different failures observed in steel material can be done by
classifying the same into:

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1. High Strength Steels
2. High strength low alloy steels
3. Tempered alloy steels
4. Quenched alloy steels
ASTM designations are provided for each of the above-mentioned steel types.
These designations are provided for light gauge cold form members, rivets,
weld filler material, wire, strand, rope, cable, forgings, castings, bolts.
Common failure observed in steel rolled shapes or sections that are
fabricated are:
 Failure caused in the welded areas
 Buckling or web crippling of the sections
 No design considerations for torsion effects result in great issues
 Support points lacks rotational restraints
 Columns lack lateral supports
 The compression flanges of the beams lacking lateral supports will
result in the failure of the structure
 Ignoring the effect of member stability to consider the overall stability
of the structure
Brittle fracture is a sudden failure occurring in steel structures that will result in
sudden collapse of the whole system. The main causes of brittle fracture
found in steel structures are:
 The loading rate on the structure is very rapid in nature
 Corrosion of steel materials – (Mostly in the critical sections, joints,
and corners where the stresses are higher)
 The loading will we provided in repeated cycles
 The welded connections of the steel structure will be highly restrained
 The tensile stress might be higher

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 Higher carbon content in the steel structure
 Having flaws or notches
Failures Caused by Concrete as a Construction Material
The concrete gain mechanical properties which is dependent on the:
 Chemical Composition of the cement
 Grading of the cement and aggregates
 Quality of water
 The mixing method and quality
 Proper placing
 Finishing of the concrete
 Proper curing conditions
 Small and large quality aggregates
 The environmental conditions to which concrete is exposed
The process of hydration bonds the various components together. This helps in
increasing the mechanical properties of the concrete. More permeable the
concrete more it attracts the moisture and other chemicals. This affects the
internal structure of the concrete and the durability is affected extremely.
The distress in concrete are caused due to the following reasons:

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1. The concrete being subjected to repeated cycles of freezing and
thawing
2. The concrete components subjected to extensive shrinkage and
expansion
3. The chemical attack of chlorides and sulfates results in change of
volume.
4. Presence of high content of alumina result in the degradation of the
strength.
5. Chlorides penetrates the concrete that results in the corrosion of the
concrete reinforcement.
6. The concrete void spaces may have bacterial fermentation which
results in the bursting and the disintegration.
Failures Caused by Masonry as a Construction Material
Increase in the moisture content makes the masonry structure to expand and
lesser moisture content makes it to contract. This is the case with brick
masonry and this deformation is not reversible in nature. In the case of
concrete masonry units, shrinkage is a major issue.
Failures observed in the masonry units are resulted from the following
problems:
1. Freezing of the water present in the joints results in the cracking.

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2. The metal ties and the structural steel members are subjected to
corrosion
3. Cracking due to settlement issues
4. Shrinkage and bending process result in the curling of the concrete
floor.
5. Movement of the masonry units induces cracks extremely
6. Thermal expansion of the masonry units will result in the tension in the
masonry. This will lead to cracks.
7. The wall that is running in the same direction may undergo shortening
and resulting in cracking of the walls.
Most of the issues mentioned is due to the lack of proper consideration of
design and detailing of the expansion and the control joint.

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Failures in Wood as a Construction Material
Wood is a unique construction material which is mainly composed of organic
cellular grained structure. Wood is hence an anisotropic material. But wood
material is assumed as orthotropic material, along three principal elasticity
directions along radial, tangential and longitudinal directions of the material.
The elastic properties of this material are thus studied by finding the Young’s
modulus. Poisson ratio and shear moduli. Most important elastic property that is
used in the design is the modulus of elasticity.
Most of the failures found in this material is associated with the:
 Moisture content
 Density
 Splits
 Shakes
 Density
 Knots
 Checks

Building notes by constructor pdf

Building notes by constructor pdf

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Building notes by constructor pdf