Lateral load performance of a reinforced concrete frame with pultruded GFRP box braces

Reinforced concrete buildings, which constitute most of the building stock in Turkey, should be examined in terms of earthquake resistance. Many studies have been carried out to increase the seismic resistance of reinforced concrete (RC) structures against earthquakes. In this study, a single-story, single-span RC frame stiffened with chevron steel braces was chosen as a reference frame and laterally loaded to failure. In the first step, the experimentally obtained static lateral load-deflection curve was verified by non-linear finite element (FE) analysis. Then, the uniaxial tensile properties of the selected glass fiber reinforced polymer (GFRP) materials were verified using FE analysis with the results found in the literature. In the second step, three different GFRP box braces with different axial stiffnesses were investigated and the results were compared with those of the steel chevron braces. Finally, the lateral load performance and expected buckling failure of the GFRP box braces in an RC moment frame have been presented and discussed in this study. Considering the lightweight of the GFRP sections, the lateral load capacity of the RC frame with GFRP braces was improved as much as the steel braces, and the maximum gain was about 47% more when the equal axial stiffness of steel brace was provided to GFRP brace. Ductility and story drift of the considered braced moment frames are presented.