变形补偿型拉索支撑加固钢筋混凝土框架抗震性能试验研究OA

To improve the seismic performance of existing RC frame structures,a deformation-compensated cable bracing retrofitting technique was proposed.In this system,steel cables with deformation compensation devices are arranged diagonally in the plane of the frame;both ends of the steel cables are anchored to the core zones of beam-column joints,and prestress is applied to the cables to convert them into inter-story lateral bracing structures.Meanwhile,the existing RC beam and columns are retrofitted using either steel jacketing or section enlargement.To verify the effectiveness of this retrofitting method,four planar frame specimens were designed,fabricated and subjected to quasi-static tests,including one was an unretrofitted frame,one was retrofitted with conventional cable bracing,and the remaining two were retrofitted with the deformation-compensated cable bracing.The test results show that both the conventional and deformation-compensated cable bracing retrofitting methods significantly improve the cracking load,yield load and bearing capacity of reinforced concrete frame structures.Compared with the unretrofitted specimens,the specimens retrofitted with deformation-compensated cable bracing exhibit increases of 197%-286%in cracking load,261%-333%in yield load,and 356%-386%in bearing capacity.Moreover,under the same horizontal displacement,specimens retrofitted with deformation-compensated cable bracing experience less damage than both the unretrofitted specimen and the specimen retrofitted with conventional cable bracing,and their post-earthquake self-centering capacity is significantly enhanced.When subjected to large lateral displacements,the cable stress increment of the specimen retrofitted with conventional cable bracing is extremely high,posing a risk of cable fracture;in contrast,the cable stress increment of the specimen retrofitted with deformation-compensated cable bracing is relatively small.This ensures that the cables remain in an elastic state even under rare earthquakes,thereby preserving their self-centering capacity.Numerical simulation results further indicate that increasing the initial cable prestress can effectively enhance both the bearing capacity and self-centering performance of the retrofitted structure.