الفهرس 
Introduction and Literature Review.Only 14 pages are availabe for public view
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Abstract
In the last few years there has been an increasing interest in improving the seismic capacity of the existing structures(rehabilitation) Considerable attention in improving the seismic capacity of the existing structures( rehabilitation) Considerable attention in researches have been directed towards the possible and feasible techniques that enhance the overall structural performance of the existing structures subjected to earthquakes. This improvement of the earthquake resistance can be achieved by increasing the building rigidity which can be accomplished by adding some strucral elements such as shear walls, struts, and/or studs. These additional structural elements have the effect of decreasing some of the dynamic parameters such as the fundamental period of vibration and the maximum drifts.
In this research, a procedure of improving the lateral resistance of the existing structures considering the main idea of the Free Spanning Virendeel System (after Banavalkar- 1992),is proposed. The main of this technique is to improve the inelastic behavior and to increase the ultimate lateral lateral resistance of existing structures .In FRHT systems, vertical steel stubs connected by proposed hinge (after Banavalkar-1992), are added to the original systems. This proposed hinge (after Banavalkar-1992)can transmit the shear forces only.
A modification has been done to the proposed resistance system(FRHT) In the modified system (SRHT), extra elements are added to the FRHT systems.
These elements are incline elements at the first floor and modified hinge to connect vertical stubs. This modified hinge can transmit both the vertical and horizontal forces that result from the seismic loads only. This modified system attracts larger portion of the lateral loads and reduces the horizontal deflections (drifts). This meets the aim of the ideal seismic rehabilitation systems either for collapse prevention or to assure comfort of the occupants during and after the earthquakes.