体育场大跨度拱式钢结构在多点地震激励作用下的反应分析

Response analysis of long-span arched steel structure of stadium under multi-support seismic excitations

以某体育场大跨度拱式钢管桁架结构为研究对象,采用ANSYS软件建立有限元模型,运用时程分析法对其进行了一致及多点地震激励作用的计算分析,通过对比一致及多点地震动激励得到的各杆件轴向应力最大值的平均值,了解其反应特点。研究表明:在多点地震激励作用下,拱结构各杆件的地震反应与一致激励作用下的情况差异较大,且变化特征较复杂。总体上看,拱架弦杆轴向应力大于一致激励下的情况,且杆件离支座越远,其应力水平越高,跨中附近的弦杆最大应力高达一致激励下应力水平的2倍左右;拱架撑杆的应力水平与一致激励下的情况接近;拱架各斜杆及竖杆的应力变化情况较复杂,但各杆总体应力水平远高于一致激励下的情况。抗震设计时尤其要注意对拱架跨中弦杆与腹杆的加强。

A study on the seismic response of a long-span arched steel structure of a stadium was carried out. Using ANSYS software to establish the finite element model, the multi-support time-history seismic responses of the mem- bers＇ axial stress were computed and compared with those of uniform seismic excitation. The study shows that, the multi-support seismic excitation responses of the arch structure are larger and more complex than the uniform seis- mic excitation responses. The arch chords＇ axial stresses are greater~ even to about 2 times, than those under uni- form excitation conditions. The arch braces＇ stresses are approximate to those under uniform excitation conditions. The oblique and the vertical members＇ stresses are more complex, and are much higher than those under uniform excitation conditions. In general, much more attention should be paid to the arch span chords and web members during the seismic design of such structures.