الفهرس 
The primary tasSeismic Resistance and VulnerabilityOnly 14 pages are availabe for public view
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Abstract
Retrofitting of constructions vulnerable to lateral loads is a current problem of great political and social relevance. In Egypt, many existing buildings are vulnerable to seismic action. Most of these buildings have ordinary non ductile RC elements, beams and columns infilled with brick walls (infilled RC frames). Many experimental and numerical studies were conducted to study the behaviour of infilled frames. Only a relatively small number of experimental studies have been performed in order to examine the impact of a thin layer of Engineered Cementitious Composites (ECC) for retrofitting infilled panel of RC- frames. So, a numerical parametric study is essential. A new seismic retrofit technique specifically for unreinforced masonry infills in nonductile reinforced concrete frames has been developed. The technique uses a sprayable, ductile fiber-reinforced cement based material referred to as ECC. Some studies used ECC sparyable as retrofitting of infilled RC frames. It has been found that the common mode of failure of such frames is the plastic hinge or shear failure of the RC-frame. Such debonding failure mode between the infill and the ECC is not occurring. In this study, behaviour of infilled RC frame was investigated using Abaqus\standard package. The analysis included 2D model using plane stress element. Moreover, the 2D model using shell element was extended to investigate the behaviour of ECC retrofitted infilled RC frames. The validated micro model was used to investigate the effect of several parameters on the overall behaviour of the bare frame, infilled RC-frames and ECC retrofitted infilled RC frames. These parameters include the 2 infill panel type, ECC retrofitting configurations. Finally, comparing between retrofitted RC-infilled frame with ECC or CFRP is constructed. Results indicated efficiently that 2D model using plane stress element was able to predict the actual behaviour of the bare, infilled RC frame and infilled RC frames retrofitted with ECC. It was also observed that the increase in column’s depth significantly increase the lateral strength, initial stiffness and cumulative dissipated energy for bare frame and infilled frame. The results have indicated the mode of failure in infilled frames can be occurred in RC-frames or infill panel and may be changed from ductile failure (four plastic hinge of column) to brittle failure (column – shear failure) in one specific story, so that the mode of failure of full scale infilled frame must be known to be retrofitted by ECC material with suitable strategy. The ECC overlay system used to retrofit infilled RC frames is significantly effective in increasing lateral strength and cumulative energy absorption capacity. An important advantage of the proposed strengthening technique is that it can be applied without evacuating the building during its application, thus causing minimum disturbance to the ongoing building function. The optimum retrofitted configuration to infilled RC- framed is that applying the ECC material on both RC-frame and brick together, it has a great effect on the lateral strength, initial stiffness and cumulative dissipated energy for the retrofitted infilled frame response. The pushover analysis utilizing the simplified macro model proved to give good matching with the micro model results. This can give a promising powerful tool for predicting the nonlinear behaviour of ECC infilled RC frames for the purpose of analysis and design of large scale structures.