مقاوم سازي ساختمان هاي بتني با سيستم هاي كابلي و بهينه سازي فرم كابل و محدوده ي نيروي پيش تنيدگي

CONCRETE STRUCTURE REHABILITATION USING CABLE SYSTEMS AND OPTIMIZATION OF THE CABLE SYSTEM FORM AND PRE-TENSIONING FORCE RANGE

In this paper, the use of cable systems is investigated, in order to rehabilitate buildings. The first system is a consistent cable system, in which pre-tensioned con­tinuous cables, with sliding connections at the floors of mid-stories, is used to increase structural lateral stiff­ness. At the end of each cable, a spring damper is used, in order to dissipate the energy. The next system in­volves X-form pre-stressed cables, which are used as X forms in one, or in multiple, span(s) of a frame. These systems can be replaced with other systems, due to the high tensile resistance of the cable, their ease of replace­ment, their high speed performance and economy, etc. They can also be used to rehabilitate existing buildings. The pre-tensioning force amount of the cables in these systems should be placed in a specific range. This range has been found for two concrete frames of three and six stories jir different cases. Using a consistent cable system, one can easily set the cable lateral stiffness at each story by changing the cable passing position from the story floor. The system was modeled using a SAP 2000 package and the optimum of the cable form was obtained. Comparing flexural frame results with the optimized case cable system showed that the most re­duction in relative lateral displacement occurred in the stories which had maximum displacement in the flexural frame system. Finally, comparison of the flexural frame with the cable system showed a considerable reduction in displacement and element internal forces