地震作用下抗震与隔震连续梁桥动力响应试验研究

针对某跨海连续梁桥的抗震和隔震性能,通过将其简化,并根据相似比1∶10制作该梁桥单墩抗震与隔震试验模型,采用铅芯橡胶隔震支座,进行抗震及隔震地震模拟振动台试验,研究分别采用120、600、1 200和2 400年一遇地震波输入时结构的加速度响应、隔震支座剪力、墩顶剪力和隔震支座滞回性能,并根据单墩低周往复加载试验结果,判别在不同地震波作用时抗震桥墩和隔震桥墩所处的状态。试验结果显示:隔震后梁桥上部结构地震加速度响应在120和600年一遇地震时减小为抗震结构加速度响应的54%和55%;随着结构响应的增加,隔震位移越大,隔震支座耗能能力越强;采用隔震后,在2 400年一遇地震时,隔震梁桥整个桥墩在弹性范围内,桥墩地震响应小于开裂荷载,而抗震梁桥在600年一遇地震时,桥墩已达到开裂荷载。

Experimental Study of Dynamic Response of Seismic and Isolated Continuous Girder Bridge Under Earthquake

For one pure continuous girder bridge across ocean, the seismic and isolated experimental model with the scale of 1:10 was designed and made in same material to actual model by simplifying continuous girder bridge as single pier model, and the shaking table test of seismic single pier model and isolated single pier model with Lead Rubber Bearing (LRB) were proceeded. Then the acceleration response, shear force of LRB, shear force at the top of pier and hysteretic performance of LRB were studied under inputting earthquake of 120-year, 600-year, 1200-year and 2400-year return period, and the state of seismic and isolated pier under different earthquake can be judged according the experimental result of low-period recycle test. Experimental results show that the acceleration response of superstructure of isolated bridge was reduced to 54% and 55% of seismic bridge under 120-year and 600-year respectively. With the increase of structural response, the displacement of isolated layer will become larger and the ability of energy dissipation of LRB will become stronger. The whole pier of isolated bridge was in the elastic state and the seismic response of pier was less the cracking load under earthquake of 2400-year return period. However, the pier of seismic bridge had been reached to cracking load of pier under earthquake of 600-year return period.