Retrofitting and Strengthening of Structures

The present case study investigates the capacity assessment and subsequent strengthening of pre-stressed concrete girders and provides additional information on the strengthening measures taken for the whole of the structure involved. It is based on an existing concrete building constructed in 1971. Structural modifications had to be made to ensure a proposed load-bearing capacity upgrade due to change of use. The building contains concrete girders pre-stressed with the post-tensioning method, the mechanical and geometric properties of which were not available, although it was known that the two-span girders were intended to meet high-capacity demands. Nonetheless, an accurate simulation of the structure was essential. For this purpose, non-destructive methods had to be employed, while safety factors were introduced in accordance with the corresponding code provisions, in order to minimize structural uncertainties. Subsequently, finite element models were created to evaluate the res...

Moderate and severe earthquakes have struck different places in the world, causing severe damage to reinforced concrete structures. Retrofitting the existing structures is one of the major challenges to face. One of the retrofit techniques of RC structural members is confinement with a composite enclosure. This external confinement of concrete by high strength Carbon Fibre Reinforced Polymer composites can significantly enhance the strength and ductility and will result in large energy absorption capacity of structural members. Beam-column joints, being the lateral and vertical load resisting members in framed RC structures are more vulnerable to failures during earthquakes and hence strengthening of the joints is often, the key to achieve successful seismic retrofit strategy.This paper depicts experimental investigations carried on RC frames subjected to broad band excitation, which are conducted to study the performance of wrapping on retrofit effects on it & the influence of Carb...

Steel greenhouse structures are generally constructed by individual sole contractors using quick empirical structural calculations (pre-engineered solutions). It is also common to import standard greenhouses from other countries, mainly from The Netherlands, Italy, and France, and sometimes from Great Britain and Israel. Evidently, these countries differ concerning the local wind and snow conditions. Therefore, there is a need for a better design of structures accepted as satisfactory, while installation can be done in a different location. Many greenhouse structures incorporating poor designs or inappropriate pre-engineered solutions are currently in use. At the same time, demolition and reconstruction represent a very expensive solution considering the loss of crop production and the demolition and construction costs; thus, strengthening is a reasonable alternative. This paper presents strengthening techniques for steel greenhouses that are code-deficient according to EN 13031 and...

Kigali, the capital city of Rwanda is a highly sloped region and the construction of roads to reach all remote areas within the city is economically and socially unfeasible. While the population in this city was increasing on daily basis, the problem with people mobility from remote areas has become a burden to the government. As the construction of new roads all around, especially in areas with that hilly topography is realistically quite expensive, both traffic congestion and long queues of people waiting buses remain daily challenges. This study on aerial cable car as alternative transport mode consisted in identification of areas with more mobility problems, analysis of respective topography and proposal of adequate lines. The review of available literature, sites exploration and interview with local people were performed. As results, five metro-cable lines were proposed and respective coordinates (elevation, location, USR, NISR) were collected using GPS. Research established that the system would be cost effective and technically feasible, as the more loaded Line C would cost 14,503,242,000 Rwf (around 14.2M Euro). Also, this transport mode was found to be sustainable as the construction cost of the line C would be covered just after 10 months of its operation.

A B S T R A C T Wildfires impact upon populations where development has occurred within or adjacent to natural vegetation. Even with extensive management interventions in the landscape, wildfires will continue to impact upon some properties. Residents in wildfire prone areas need to prepare themselves and their properties. Studies have found cost is one of the main reasons there is a generally low level of preparation by residents. In this study, we quantify the cost for residents to prepare themselves and retrofit their property for wildfire in an intermix and interface community. We combine this with semi-structured interviews to identify limitations to preparedness and willingness to contribute to a shared cost scheme with local government. Wide variation in the level of preparedness was found for the five case study homes in the intermix area and the five in the interface area with intermix houses being better prepared than those at the interface. All buildings were found not to comply with any building standards for wildfire resilience, despite most being considered to have the highest level of wildfire exposure. The total up-fronts cost to prepare residents and their homes ranged from approximately $8500 to $47,000 with an average of $24,600. Based on these figures, the financial investment required was significantly higher than residents felt they were able to cover. Ultimately, the choice to live in a wildfire-prone area will always involve the acceptance of some risk, regardless of the construction of the property and preparedness of the household.

Engineers are often overwhelmed with laborious work while analyzing bearing capacity and settlement behaviour of shallow foundations. This is largely due to the number of iterations required under various empirical design considerations. To mollify this challenge, an effort is made in this research to develop a spreadsheet-based solution that can effectively, accurately and timely resolve bearing capacity and settlement problems of shallow foundations. The Microsoft excel (2010) package was used to develop a user-friendly, accessible, economical and analytical program to evaluate settlement and ultimate bearing capacity problems. It offers user-controlled parameter panels while the analysis and calculations are done automatically. A sample question was adopted, manual calculations were made, and a comprehensive Microsoft excel spreadsheet was developed. The spreadsheet analysis template was based on Terzaghi’s method for the ultimate bearing capacity and Gazeta’s method for the settlement analysis for different shape of footings under varying water levels for the same sample question.  Comparisons were made to see the variation between the manual calculation and the Microsoft Excel spreadsheet that was developed. The difference between the manual calculation and the Microsoft Excel spreadsheet in the bearing capacity analysis is less than 0.50kN/m2 which is within an acceptable range and in the settlement analysis, there is no significant difference between the Microsoft excel spreadsheet and the manual calculation for all the footing types.

A state-of-art of traditional and modern retrofitting techniques emphasizing the advantage of the use of metallic materials. General issues of structural intervention starting from the mechanical causes of damage, the logical phases of intervention, the technical and administrative steps and different levels of consolidation are shortly over viewed. The main characteristics of the new strategies for anti-seismic protection of buildings are presented.

Ujjayanta Palace, standing in the heart of Agartala city, in Tripura, a famous royal house, covering an area of 1 sq. km. and styled in Greek sculpture, was built by Maharaja Radhakishore Manikaya in 1901. The two-storeyed palace has a mixed architecture with three high domes (the center one being 26 m high). Ujjayanta Palace, a declared heritage building, has been in existence for the past 110 years and the environmental effects have taken their toll. A detailed survey of the existing structure and the surrounding soil strata was made. The properties of the building materials were assessed using modern techniques. The soil was found to be prone to liquefaction in the event of an earthquake. It was decided to carry out extensive retrofitting of the palace without in any way altering its architectural features. The criteria adopted for undertaking the retrofitting was to permit the structure to undergo deformation without brittle failure or loss of life during design basis earthquake and to limit the damage to minor repairable cracks when the structure was subjected to maximum considered earthquake. In this paper, details of the assessment of the palace structure and the environment are presented. Further, a comprehensive description of the retrofitting techniques adopted and their efficacy are explained.

Sustainability has become a fundamental requirement for the future of our cities.
This requirement is mostly associated with environmental issues, and a great effort has been made in the past years to build a low-carbon society. However, sustainability must also be associated with safety.
As a consequence, in seismic countries, sustainable cities must be not only low-carbon-emitting bust also earthquake-safe.
This concept represents the basic premise of this book.
According to this premise, in earthquake-prone nations like Italy—where most of the building stock is both highly earthquake-vulnerable and energy-consuming—energy renovation actions should be combined with seismic upgrades. Nevertheless, many barriers significantly limit the real possibility of undertaking combined retrofit measures, especially in the case of multi-owner housing and high-rise buildings. These barriers are of different kinds: economic/financial (high renovation costs, insufficient incentives and subsidies, landlord-tenant dilemmas, etc.), technical (ineffectiveness of conventional upgrade solutions, need of regulatory simplification, etc.), organizational (occupants’ dislocation and disruption, consensus to the retrofit expenditure by condominium ownerships, excessive time for getting construction permits, etc.), and cultural/social (insufficient information and skills, lack of adequate policy measures for promoting renovation actions).
This book aims to overcome these barriers and to bridge the gap between sustainability and safety, so to conserve both human and environmental resources. It brings together 11 contributions on different seismic and energy renovation measures, proposing technical solutions at district, building, and component level, for both historic and modern case studies.
Finally, I would like to thank the editorial team of Sustainability for inviting me to guest-edit the Special Issue on “Energy and Seismic Renovation Strategies for Sustainable Cities” which has been transformed into this book. I also thank all the authors and reviewers for their fundamental contributions.

Timber load bearing floor structures of Italian historical constructions are complex systems made of girders, joists, subfloor, and completing components (lath to cover planking joints, small boards to cover the link between joists and girders, etc.). These floors are placed in and connected with the load bearing walls, thus constituting a more complex structural system.
The need of strengthening of timber load bearing floors could issue from: timber decay (due to insects, fungi, fire, or creep), increase in loads, changes in safety and serviceability standards.
Actual cases show countless states with regard to: building techniques; material state of preservation; size of the gap between required and provided performances; aesthetical, historical and material interest of ceiling and flooring.
In the light of contemporary architectural preservation theories, several values must be considered while choosing from among the conceivable systems for the strengthening of timber floors: aesthetical quality; signs of usage; technological features; material characteristics. Other needs must also be evaluated along with those values: the requirement to assure physical and aesthetical fruition of the building; the need to respect the original technological conception of the structure; the compatibility of the strengthening solutions with the existing structure, the possibility to remove it, and maintain it in efficiency; moreover the added elements should be clearly recognisable as contemporary.
This paper aims to single out the primary values to be considered, and to assess the most common strengthening solutions with regard to these aspects and to the actual state of the floor structure.

— in the present study, the steel jacketing technique with variable vertical angles size connected with horizontal steel straps is used to upgrade the load carrying capacity of rectangular reinforced concrete columns under eccentric loads. Seventeen reinforced concrete rectangular columns were loaded and tested under different eccentricities until failure. Each column has 120x160 mm cross section and 1000 mm length with four normal mild steel bars 8 mm diameter as a vertical reinforcement and 6 mm diameter horizontal normal mild steel (stirrups) with 120 mm spacing. Five columns non-strengthened were tested under different eccentricities (e/t = 0, 6.25 %, 12.50 %, 18.75 % and 25.00 %) as control columns. However, twelve columns were divided into three groups strengthened with two external angles 20x20x2 mm, 40x40x2 mm and 60x60x2 mm in compression side respectively and two external angles 20x20x2 mm in tension side for all strengthened columns. The strengthened columns were tested under different eccentricities (e/t = 6.25 %, 12.50 %, 18.75 % and 25.00 %). Numerical analysis using the finite element technique has been conducted to simulate the response of control and strengthened columns. A finite element commercial package "ANSYS version 15" is used in the present analysis. The results of the finite element model have fair agreement with the experimental results. The validated finite element model was used to conduct parametric analysis for practical design applications. Columns with cross sectional areas ranging from (25x30) cm to (25x120) cm; strengthened with different angles size subjected to eccentricity (e/t) 10% , 20% and 30% were investigated. The columns were 300 cm in height and have vertical reinforcement 1 % of the concrete cross sectional area; 8 mm stirrups spaced at 20 cm were provided for all columns. The columns were strengthened using 2 vertical angles of different size in tension side and 2 vertical angles of different size in compression side welded by horizontal straps 50 cm apart. The dimensions and thicknesses of the angles were identified for each column according the needed level of strengthening. Each column is strengthened to reach the original column carrying capacity. The results showed that increasing the covered area of the steel jacket as well as increasing cross sectional area of the steel angles increases the load carrying capacity of the strengthened columns. The relationships between the strengthened columns and the corresponding dimensions of the angles are presented in tables for practical applications.

Steel greenhouse structures are generally constructed by individual sole contractors using quick empirical structural calculations (pre-engineered solutions). It is also common to import standard greenhouses from other countries, mainly from the Netherlands, Italy, and France, and sometimes from Great Britain and Israel. Evidently, these countries differ concerning the local wind and snow conditions. Therefore, there is a need for a better design of structures accepted as satisfactory, while installation can be done in a different location. Many greenhouse structures incorporating poor designs or inappropriate pre-engineered solutions are currently in use. At the same time, demolition and reconstruction represent a very expensive solution considering the loss of crop production and the demolition and construction costs; thus, strengthening is a reasonable alternative. This paper presents strengthening techniques for steel greenhouses that are code-deficient according to EN 13031 and Eurocodes. Consequently, two case studies are presented as typical applications of greenhouse structure strengthening.

This article presents a concise overview on condition monitoring and retrofitting/ strengthening of structures including a practical case study of strengthening for an existing historical building. Condition assessment of an existing structure is required mainly to check serviceability and safety requirements of the structure after short term events like earthquake or long term degradation of the structure with time. It is carried out to assess the ability of a structure to perform its intended operations under changed loading conditions with time or modification in its structural system as per newly imposed requirements. The condition assessment and strengthening may also be required for integrated extension of an existing structure. After assessing the condition of the structure, either it is retrofitted (or  strengthened) or it is demolished according to the severity of the damage. In this article, such a critical condition assessment for an existing historical masonry building is presented and appropriate strengthening schemes are suggested by following two separate measures (concrete jacketing and fiber reinforced polymer strengthening). Subsequently, the relative advantages and disadvantages of the strengthening measures are discussed from a practical engineering perspective. Aim of this article is not to propose any new method for condition assessment and strengthening of structures, rather we take a systematic approach to demonstrate our experience. Critical case studies on condition assessment and strengthening of historical buildings with adequate technical insights are very scarce to find in scientific literature. This article would serve as a valuable reference for the practicing engineers and the concerned scientific community.

Abstract— An experimental study was performed to investigate the behavior and strength of proposed technique to connect reinforced concrete (RC) beam to steel or composite columns. This approach can practically be used in several types of building construction. In this technique, the main beam of the frame consists of a transfer part (part of beam; Tr.P) and a common reinforcement concrete beam. The transfer part of the beam is connected to the column, whereas the rest of the beam is connected to the transfer part from each side. Four full-scale beam-column connections were tested under static loading. The test parameters were the length of the transfer part and the column properties. The test results show that using of the transfer part technique leads to modify the deformation capabilities for the RC beam and hence it increases its resistance against failure. Increase in length of the transfer part did not necessarily indicate an enhanced behavior. The test results contribute to the characterization of the connection behavior between RC beam - steel column and can be used to calibrate numerical models for the simulation of this type of connection.
Keywords— composite column, reinforced concrete beam, Steel Column, Transfer Part.

ABSTRACT: The general topic investigated in this thesis is “structural health monitoring”, with special care being devoted to damage detection and localization. The study is focused on methods which work in the space of the observed variables, where the global information measures can be used to detect the damage. In this context damage detection is demanded to global measures such as entropy or Lyapunov exponents. The comparison of these measures computed in subspaces of the observed variables or in their expansions, allows one to perform a sort of sensitivity analysis on the role of the variables involved in the problem.
Such global measures are able to detect but not to directly  localize damage. For this purpose, a new approach to detect and localize the damage is formulated and implemented. It exploits response surface techniques to approximate the relationship among the observed variables. Comparing the resulting models in different damaged and undamaged situations identifies the response differences and their causes.
The response surface procedure is described from its basic theoretical aspects up to the features of its numerical implementation. Additionally, the global measures introduced above drive the analyst in establishing whether or not the problem is well posed, i.e., whether or not the set of measured quantities are able to detect the specific damage to be localized.
The validation of the proposed methodology is first numerically pursued by applying it to the benchmark case set up by the Structural Health Monitoring Panel of the American Society of Civil Engineering (ASCE). The procedure is then tested on two different experimental situations. While the first study of a three-dimensional steel frame reproduces the features of the benchmark problem, the second investigation covers a monumental structure situation, where damage is represented by more or less extended cracks in the masonry. The potential expressed by the procedure also in this second application seems to promise interesting exploitation possibilities.

Haussmann buildings architecture spread throughout the city of Paris. Nevertheless, those buildings are nowadays submitted to heavy operations of use change, conservation and rehabilitation, justified by several reasons, among others are building aging and the increasing demand for hotel rooms in Paris. In this paper, concrete pouring, an underpinning construction technique applied to a Haussmann building complex to create an additional basement floor is described. This description is the result of a construction survey realized during a heavy rehabilitation operation which takes place between 2015 and 2017 in a Haussmann complex located at La Madeleine. This work aims at providing contributions for a better understanding of concrete pouring technique, complementary an evaluation of the risks associated with this technique is done. The knowledge from this work could be very useful for the study of underpinning numerical modeling techniques or issues related to sustainable rehabilitation and strengthening, aiming to preserve this important building heritage or similar ones existing in other countries.

The objective of the study is to evaluate the effect of
using silica fume on the properties of fresh and hardened
concrete made with crushed bricks through experimental
investigation. The effect of using silica fume on the workability of concrete due to addition of silica fume was measured by taking the slump of the concrete produced with and without silica fume. The strengths and stiffness were experimentally determined for the hardened concrete. For the hardened concrete, cylinders and prisms of standard dimensions were cast for a particular mix ratio at constant water cement (W/C) ratio with and without adding silica fume. The casted specimens were tested for determining the tensile, compressive and flexural strength of concrete made with crushed bricks as coarse aggregate. From the investigation, it has been found that the workability, strength and modulus of elasticity of concrete increases with the addition of silica fume. It has also been found from the investigation that the enhancement effect using silica fume increases with the age of concrete.

The premature failure problem of  beams strengthened with external plates reduces  its  efficiency.  Although  this  problem  is considered  in  different experimental and analytical studies, more effort is required to increase the efficiency  of  such  expensive  strengthening  technique.  As  part  of  a comprehensive  program,  this  experimental  study  i s  applied  on  eleven continuous  reinforced  concrete  (R .C )  beams  and  nine  full -scale  simply supported R.C beams. The effect of using different materials and schemes for  external  reinforcing  was  investigated  on  the  overall  behavior  of  the strengthened  beams.  Behavior  of  beams  strengthened  with  the  proposed  schemes was  explored  considering  its practicality and cost of strengthening. The  ultimate load  of the tested beams were compared with the design load
calculated using the ACI 440-02 guidelines for external flexure and shear
strengthening of beams. Generally,  controlling the shear cracks propagation by using web plates and  reducing stress concentration and crack propagation along  the  strengthening  plate  delays  the premature  mode  of  failure and correspondingly  enhances  significantly the strengthened  beam’s  capacity and ductility.  Due to their significant  effect, different common  strengthening schemes need to be considered in any proposed design guidelines for more economic and reliable applications.

Ce rapport contient le plan de réduction des risques d’inondation de Larba Birno, village administratif de la commune rurale de Gothèye, région de Tillabéri, Niger. Larba Birno (4 713 habitants en 2012, 0,7 km2 de surface bâtie en 2018) est situé le long de la rivière Sirba, l’un des principaux affluents du fleuve Niger moyen. Le village est menacé par les inondations fluviales et pluviales. Le plan est structuré selon l’ISO 31010. L’analyse intègre les connaissances locales et scientifiques. Le processus de planification est entièrement participatif. Le risque d’inondation est identifié et analysé. Les zones inondables sont identifiées en fonction de trois scénarios de probabilité d’inondation des rivières grâce à une modélisation hydraulique 1D. Les biens inondables sont identifiés par photo-interprétation visuelle d’images à très haute résolution capturées par un véhicule aérien sans pilote en septembre 2018. Neuf mesures de réduction des risques sont sélectionnées et classées par ordre de priorité. L’analyse bénéfice/coût est utilisée pour évaluer l’opportunité de traiter ou d’accepter le risque. Le dispositif de suivi-évaluation est décrit. Le plan se compose de la réglementation des zones inondables, des cartes d’aléas, des enjeux, du zonage règlementaire, et de fiches décrivant chaque action prioritaire.
------ ENGLISH. This report contains the Flood Risk Reduction Plan for Larba Birno, an administrative village of the rural municipality of Gothèye, Tillabéri region, Niger. Larba Birno (4713 inhabitants in 2012, 0.7 km2 of built up area in 2018) is located along the Sirba River, one of the main tributaries of the middle Niger River. The village is threatened by fluvial and pluvial floods. The plan is structured according to the international standard ISO 31010. The analysis integrates local and scientific knowledge. The planning process is fully participatory. Flood risk is identified and analyzed. Flood-prone zones are identified according to three river flood probability scenarios through a 1D hydraulic modeling. Floodable assets are identified through visual photointerpretation of very high resolution imagery captured by an Unmanned Aerial Vehicle in September 2018. Nine risk reduction measures are selected and prioritized. Benefit/cost analysis is used to assess the convenience of treating or accepting the risk. The monitoring and evaluation system is described. The plan consists of the flood zone regulation, hazard, assets, and zoning maps, and sheets describing each priority action.

This study presents an experimental–analytical investigation on the structural behavior of precast prestressed hollow core RC slabs strengthened in flexure by CFRP laminates. Externally bonded and near surface mounted (NSM) laminates were used. The CFRP area and using transverse anchorage were also
investigated. Results demonstrated that NSM technique resulted in optimum strengthening efficiency. The increased bond strength also resulted in full activation of the NSM laminates at failure. However, the NSM flexural strengthening level should be carefully designed to avoid unfavorable shear-tension failure mode. Moderate efficiency was associated with the externally bonded technique due to the premature de-bonding. However, this efficiency was optimized by using transverse CFRP laminates as anchorage, which re-directed de-bonding further away from the laminates’ ends and delayed failure, but at much lower deformations than those of the control slab. A rational analytical study was conducted. Comparisons between the experimental and analytical results demonstrated satisfactory agreements.

An experimental study is presented in this paper on the behaviour of square R. C. columns of size 750 × 150 × 150 mm retrofitted with Glass fibre reinforced polymer (GFRP) sheets along with a brief review of literature. One column without GFRP and four columns complete wrapped with one, two, three and four layers of GFRP sheets have been tested for axial loading. The failure axial loads and failure modes of the columns have also been observed. A critical discussion is made with respect to increase in the strength of retrofitted columns with respect to the column without GFRP in order to explore the optimal use of GFRP for strengthening the R. C. columns. Further, an analytical model of RC column retrofitted with externally bonded FRP has also been proposed in compatibility with IS: 456-2000 [1] as the design guidelines on strengthening/retrofitting of concrete structures using externally bonded FRP laminates/sheets are yet to be recommended in India. The experimental ultimate load carrying capacity of columns is also compared with that of the respective columns predicted from the present analytical model and literature.

The present case study investigates the capacity assessment and subsequent strengthening of pre-stressed concrete girders and provides additional information on the strengthening measures taken for the whole of the structure involved. It is based on an existing concrete building constructed in 1971. Structural modifications had to be made to ensure a proposed load-bearing capacity upgrade due to change of use. The building contains concrete girders pre-stressed with the post-tensioning method, the mechanical and geometric properties of which were not available, although it was known that the two-span girders were intended to meet high-capacity demands. Nonetheless, an accurate simulation of the structure was essential. For this purpose, non-destructive methods had to be employed, while safety factors were introduced in accordance with the corresponding code provisions, in order to minimize structural uncertainties. Subsequently, finite element models were created to evaluate the res...

The failure criteria from rock mechanics, Hoek-Brown and Johnston failure criteria, may be extended and modified to assess the ultimate compressive strength of axially loaded circular fiber reinforced polymer (FRP)-confined concrete columns. In addition to the previously modified Hoek-Brown criterion, in this study, the Johnston failure criterion is extended to scope of FRP-confined concrete, verified with the
experimental data and compared with the significant relationships from the current literature. Wide-range compressive strengths from 7 to 108 MPa and high confinement ratios up to 2.0 are used to verify the ultimate strengths in short columns. The results are in good agreement with experimental data for all confinement levels and concrete strengths.

Steel greenhouse structures are generally constructed by individual sole contractors using quick empirical structural calculations (pre-engineered solutions). It is also common to import standard greenhouses from other countries, mainly from The Netherlands, Italy, and France, and sometimes from Great Britain and Israel. Evidently, these countries differ concerning the local wind and snow conditions. Therefore, there is a need for a better design of structures accepted as satisfactory, while installation can be done in a different location. Many greenhouse structures incorporating poor designs or inappropriate pre-engineered solutions are currently in use. At the same time, demolition and reconstruction represent a very expensive solution considering the loss of crop production and the demolition and construction costs; thus, strengthening is a reasonable alternative. This paper presents strengthening techniques for steel greenhouses that are code-deficient according to EN 13031 and...

The corrosion is a serious problem of construction projects that affect structural durability. The effect of corroded stirrups at the behaviour of reinforced concrete beams especially on ultimate shear strength and ductility was investigated in this study. Eight specimens of reinforced concrete beams were tested with four-point loading until failure. The dimensions of the specimen were 150 mm wide, 200 mm high and 1200 mm long. Six specimens were accelerated through an electrochemical process. The main variables of this study were the stirrups diameter and corrosion level. The results concluded that the stiffness and strength reduced in corroded beams when compere with control specimens. This reduction exhibited to increase with the level of mass loss in stirrups and a smaller diameter of stirrups. In addition to that, the ductility index trended to reduce from 118% to 68% for groups A (Ø6 @ 200 mm c/c); while from 68% to 35% for group B (Ø8 @ 150 mm c/c) which indicates that brittleness of beams raised. At high corrosion level, failure modes may change from shear-compression failure to rupture of stirrups. 1. Introduction The most significant deterioration problem of reinforced concrete structures is the corrosion of embedded steel reinforcement spatially in the marine environment and de-icing salt. As a result, the corrosion could decrease the stiffness, shear capacity, the serviceability and ultimate strength of structural elements. As known, stirrups had the main effect in shear stress of reinforcement beams, and the sufficient number of stirrups in reinforcement concrete (RC) member made the dowel action more efficient to restrict the diagonal cracks and improve the shear capacity of the member. As the stirrups are the nearest reinforcement bars to the concrete´s surface, the stirrups exposed firstly to chlorides attack before the longitudinal steel bars especially at the marine environment and find a result, the opening of cracks will quickly increase, while the cracks in the area without stress [1]. Rodriguez et al. [2] had been studied the effectiveness of corroded reinforcement in RC beams. The main results absorbed that change of failure mode could transfer from bending failure in control beams to shear failure in corroded beams. The deterioration of structures happens because of the reduction in the cross-sectional area of the reinforcing steel bars and bond losses between steel and concrete. This resulting from corrosion rust that occupied six times the original steel volume, which causes cracking and spalling of surrounding concrete so that the distribution of stresses can be affected [3]. The mechanism of mode failure in corroded beams is determined either by the shear-span ratio or by degree of corrosion [4]. Christopher et al. (2010) [5] concluded that the maximum depression in the ultimate shear strength of corroded beams had happened with the lowest a/d ratio, shear span-to-depth ratio, about 53%. The result due to the ultimate strength of corroded beams with a small shear span effected by cracking and spalling of concrete cover. Moreover, the bond strength of stirrups had little effect on the shear performance of RC beams [6]. On the other hand, Zhao and Jin (2001) and