Effect of using bracing members in reducing thermal effects in long buildings

Abstract EN

The objective of this research is to know if a reinforced concrete one-story long building can be build in hot weather countries like Iraq without dividing it into segments by expansion joints.

Three case studies were chosen in this research, the first case represents an analysis of a building (150 m length with nearly equal spans) subjected to gravity loads.

This building is designed using the specification ACI- 318M-08.

In the second case study the same building is analyzed with two types of loads, the same gravity loads and thermal load by exposure the building in the same time for 19 0C (66 F) uniform temperature increasing.

Also, and to minimize the lateral deflection producing from temperature effect, bracing beams are added at external bays in the long direction of the building.

In the third case study, the applied load in the second case study is used to analysis the building but without bracing beams.

The analysis results show that the bracing beams have large effect on the structure, the axial forces in the beams are increased by 1775 %, the moments in the columns are reduced by 80 % and the lateral displacement of the building is reduced by 77 %.

In spite of the increase in the axial forces in the beams as a result of bracing and thermal load, the strength capacity for beams in the second case is adequate to resist the increase in axial loads with the same ratio of reinforcement required to resist the flexural moments for the beams in the first case.