الفهرس | Only 14 pages are availabe for public view |
Abstract At present, the symbol of leadership and economic power is the skyscrapers. Therefore, engineers have developed many structural systems, which are efficient for tall buildings as shear walls, core perimeter frame, tube-in-tube, spin walls, and core-outriggers with or without belt truss,… etc. Among these systems, core with outrigger system is considered as one of the most effective systems for tall buildings. This study concerns with the topology and size optimization of the outrigger system. In this research, a commercial reinforced concrete structure of 42-stories with 3m story height is considered as a base of different cases of studies. The building consists of a central RC core, exterior columns and marginal beams. The reinforced concrete structure was provided by two outriggers at their optimum locations using different five topologies of trusses to find out the optimum choice among them. The structure was subjected to lateral loads as wind and earthquake loads. Earthquake loads were calculated according to different codes as ECP 2012, EC8 2004, and ASCE 2017 to compare the results between them. Five structural models, in addition to the structure without outrigger, were analyzed using ETABS software and many mathematical models were developed by MATLAB for optimization the dimensions of the outrigger system. The results of ECP and EC8 were very close. The equivalent static force wasn’t sufficient for high rise building in all codes especially in ASCE 2017. The topology A (x-shaped) was the optimum topology. Using belt truss reduces the lateral displacement at the top of the building by about 2.5%. Increasing marginal beam thickness from (70 to 100) cm enhanced the resistance of the lateral loads and reduced the lateral displacement at the top by 9.3 %. The optimized dimensions of the outrigger system were decreased when the grade of strength of concrete and the number of outriggers increased. |