连梁装置在地震序列作用下的作动分析

Unseating Prevention Devices Under the Excitation of Earthquake Sequence

地震荷载是一种随机荷载,桥梁结构受到罕遇或超预期地震作用时,抗震措施能够有效地减小地震荷载的破坏程度。连梁装置是公路桥梁防落梁系统中的最终安全保护措施,用于避免桥梁上、下部结构相对位移过大、支座丧失支承功能后发生落梁。结合国内外连梁装置的相关设计标准,对设拉索式连梁装置的结构进行罕遇地震及强震序列动力时程分析,得出连梁装置的防落梁效果及内力随其拉索长度、设计位移量的变化规律。在地震作用下,经合理设计的连梁装置起到防落梁效果,增大结构的整体性、提高结构的抗推刚度,使地震荷载在各墩间平均分配。连梁装置在整个强震序列激励过程中均起到防落梁作用,可保证有损结构的通行能力,达到"大震不倒"的抗震设计原则。

Earthquake load has the character of random. The uses of anti-seismic measures have been proved to be effective on the reduction of bridge seismic damage when the bridges encounter with rare earthquake or unexpected earthquake. Unseating prevention devices are the ultimate security installment in the collapse-proof system, which used to protect the substructure falling down from piers as the supports lose their effectiveness. Based on relational design standards at home and abroad, time-history analysis has been conducted on the structure with cable-unseating prevention devices under rare earthquake and strong earthquake sequence. The variation laws involving the collapse-proof result of unseating prevention devices and effect of collapse-proof changing with both cable length and designed value for displacement have been obtained. Under rare earthquake, the rational unseating prevention devices could provide the ultimate security to the structure, increase the integrity and anti-pushing rigidity of the structure, and make the seismic load to be well- distributed among the piers. The unseating prevention devices are able to provide the ultimate security for the damaging structure under the strong earthquake sequence; and achieve the request that there is no collapse when strong earthquake occurs.