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Structural audit of RCC building
Structural audit of RCC building
Structural audit of RCC building
Structural audit of RCC building
Structural audit of RCC building
Ijariit JournalRelated Papers
Buildings constructed during early 70's & late 80's of the last century in India are found to be in distressed conditions due to inadequate specifications and poor construction practices. The continuous monitoring of concrete structures using suitable NDT (Non Destructive Testing) methods and use of possible restoration methods help in a considerable reduction of the rate of deterioration of concrete structures thereby increasing the life span of structures. NDT methods have greater advantage in evaluating the uniformity, homogeneity, approximate compressive strength, durability, the extent of corrosion of rebars in concrete etc. of damaged structures. The objective of the present study is to enhance the life of 50 year old existing hospital building (Partly RC and Brick masonry) in Kurnool, Andhra Pradesh. Condition assessments are carried out through a visual, field and laboratory evaluation of samples collected from the structure and results are presented in this paper. The paper also highlights the assessment of strength and durability of concrete to evaluate the extent of distress and damage in the building. Besides visual inspection, the Non Destructive Evaluation covering UPV & Rebound Hammer values and Half Cell Potential with respect to the status of corrosion of reinforcing bars and chemical tests on selected un-distressed RC columns, beams, and slabs are also presented and discussed. The repair and strengthening techniques using the latest materials and possible restoration works such as column jacketing, shotcreting, anticorrosive coatings, etc. have been suggested to enhance the life of the structure.
This paper deals to create awareness amongst the civil engineers, residents and owners of building towards the health examination of existing concrete buildings called as Structural Audit. The need of structural audit is for maintenance and repairs of existing structures whose life has exceeded the age of 30 years to avoid any mishaps and save valuable human life. The concrete is widely used as construction material being inexpensive, easy for construction, applications and because of it high strength-cost ratio. More than ever, the construction industry is concerned with improving the social, economic and environmental parameters of sustainability. In India, from 1980 onwards the infrastructure industry witnessed stepping up of public investment and growth in infrastructure industry which results in construction of new multistory concrete apartments which are now in the age of thirty plus years. There are many buildings during this period and earlier have reduced strength in due course of time because of structural deficiency, material deterioration, unexpected over loadings or physical damage. If, further use of such deteriorated structure is continued it may endanger the lives of occupants and surrounding habitation. There is demand of appropriate actions and measures for all such building structures to improve its performance and restore the desired functions of structures which may leads to increase its functional life. The periodical structural auditing and diagnosis for health of existing buildings is thus utmost important for finding the present serviceability and structural viability of structures. The structural audit must be carried out following auditing norms, methods of non-destructive testing and code provisions. The structural A.B. Mahadik & M.H. Jaiswal 412 auditing will help to implement maintenance and repair work timely which leads to prolonged life of the building and safety of the occupants.
Study has been aimed to establish a structured solution for rehabilitation and retrofitting of fire damaged concrete buildings. This study explains the rehab process of fire damaged concrete buildings in three basic categories; condition evaluation, decision making, rehabilitation & retrofitting. Evaluation method of damaged building has been based upon understanding of material properties at elevated temperatures, condition survey and condition assessment. Condition survey includes visual inspection, hammering and chiselling techniques whereas condition assessment includes both non-destructive and destructive tests that are selected upon the basis of efficiency, economy, and performance. Feasibility study is required to make right decisions for the rehab of fire damaged building. Such a feasibility study should include all important aspects that will have an impact in the future, therefore must be considered in decision making. A new feasibility analysis model is developed as a part of research. It is expected to help decision making process because of its sound conceptual foundation and detailed structure. If feasibility study reveals rehabilitation and retrofitting worthwhile then it can be effectively rehabilitated with the help of right techniques. Rehabilitation of non-structural members/elements and retrofitting of structural elements with the help of soda blasting, patch repair, FRP reinforcing, partial removal and replacement, concrete jacketing, steel jacketing and few other retrofitting techniques has been discussed. Respective pros and cons of these techniques have been covered with special focus on sustainability, economy, efficiency and limitations. These techniques can be used separately or in conjunction with other techniques. As every locks has its own key similarly every case has its unique solution therefore it can’t be said that which technique or set of techniques is universally superior to others. Generally speaking, partial removal and replacement offers more advantages. It seems to have more ticks and less crosses when compared to others
Monitoring of concrete structure like buildings, bridges etc is very essential to ensure safety, stability and serviceability. The structure should, not only being safe, also be functioning as its intended use. Heavy cracking, excessive deflections, corrosion, spalling of concrete, surface stains are main characteristics of the degraded properties of a RC structure. The final goal of condition assessment of a building is to find the urgency of repair, nature of repair and cost associated with repairing. A condition assessment model based on five parameter: Visual inspection, ultrasonic pulse velocity, resistivity of concrete and age factor was prepared. On the basis of above condition index, repair urgency associated with structure was assigned. Prepared model then applied to existing structures.
The estimation of mechanical properties of concrete can be carried out by several methods; destructive and non-destructive. In this contest, the crushing of the samples is the usual destructive test to determine the concrete strength. The rebound hammer test and the ultrasonic device are used in the field of non-destructive tests to determine respectively the compressive strength and the ultrasonic pulse velocity (UPV) in the concrete. Three slabs of 1.5’×1.5’×0.5’ size with mix ratio 1:2.5:3,1:2:2.7 & 1:1.75:2.25 and water cement ratio of 0.47, 0.43 and 0.40, respectively are casted along with three cylinders for each case. Rebound hammer test and UPV are performed over slabs, cylinders and cores from slabs. After that, crushing strength of cylinders and cores are determined. In this study semi destructive and non-destructive test of concrete are carried out and the test results are compared with the representative cylinder strength to establish a relationship among them. It is observed that, the equations f^' c=12.419V-30.848 and f'c = 0.1206e1.2887V govern the relation between compressive strength and ultrasonic pulse velocity when it is straight line and exponential respectively. The R-squared values are found as 0.8001 and 0.7991 for linear and exponential relation, respectively. The relation between compressive strength and UPV shows more accuracy for straight line compared to exponential. Besides, the equation f'c(core) = 1.2938f'c(cylinder)- 3.6114 governs the relation between core strength and cylinder strength. The R-squared value has been found 0.8973. It is also observed that the core strength is found higher than the cylinder crushing strength by an amount of about 7% to 19.5%. The cylinder strength and core strength differs with NDT prediction by an amount of 7% to 20% and 23% to 26%, respectively. Finally it can be concluded that, the strength predicted by NDT and core cutting method are very close to the cylinder crushing strength (f’c), and can be used for the estimation of representative concrete strength and quality of concrete of an inbuilt RCC structure.
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