【摘要】 该文以地震下、修复中以及修复后遭遇地震的钢筋混凝土框架的动力特性为研究目的,进行了框架模型的初次振动台试验、震损后修复和再次振动台试验。试验对象为相似比1/4的双跨8层混凝土框架。在初次振动台试验中,框架模型经过31个工况地震波和5次白噪声的输入,结构破坏明显。其后,对框架损伤区域的裂缝进行压力注胶修补,并通过地脉动法和撞击荷载法监测修复过程中结构动力特性的变化。修复后,再次进行工况相同的振动台试验。试验结果表明:框架模型的频率随输入地震动幅值的加大而明显降低,阻尼比则随之明显增大;修复过程中,结构的频率和阻尼比逐步恢复,第一自振频率达到甚至超过模型的原有水平;修复后的再次振动台试验中,模型的频率降幅及阻尼比的增幅均低于初次振动台试验。结合两次试验中结构的变形幅度可知,结构动力特性与其抗震性能有密切的关系。通过动力特性指标的变化,能有效反映框架结构在震损及修复中的抗震性能。更多还原

【Abstract】 A 1/4-scale two-bay eight-storey reinforced concrete frame was tested on shaking table.After the initial shaking table test,the damaged frame was repaired using epoxy injection technique,and then subjected to the same acceleration record input selected for the initial tests.The variations of dynamic characteristics were investigated experimentally,such as the natural frequency and the damping ratio throughout the whole process by micro-tremor test,impact test and white noise test.The test result indicated a characteristic decrease of natural frequency and an increase of structural damping in the damage process,while the situation was opposite in the retrofitting process.Compared with the initial test,the decline of natural frequencies and the growth of damping ratios were smaller in subsequent test.According to the response of the frame in two shaking table tests,the dynamic characteristics have close relationship to the seismic resistance capability.With the variation of the dynamic characteristics,the earthquake resistance capability of damaged/repaired frame can be predicted effectively.更多还原