Multi-support And Multi-dimensional Seismic Response Analysis Of Long-span Spatial Structures

The seismic spatial effect should be considered in the seismic response analysisfor long-span spatial structures, of which the supports move out-of-step underearthquakeexcitation.Butthepresentmethodsofseismicdesignignorethiseffect.Soit is necessary to study the influence of seismic spatial effect. In this thesis, theseismic response analysis methods for long-span spatial structures under multi-pointand multi-dimensional stationary earthquake excitations were studied. The mainresearchworkcoversthefollowingaspects:(1)The pseudo excitation method was introduced to analyze the seismicresponse for long-span spatial structures. The random vibration approach forlong-span spatial structures under multi-point and multi-dimensional stationaryearthquakeexcitationusingpseudoexcitationmethodwasstudied.(2)The influence of partial coherence effect and wave passage effect onrandom seismic responses of long-span spatial structures was studied. Also, theinfluence of the direction of seismic wave transmission on random seismic responsesof long-span spatial structures was studied in detail, which may further complete thetheoryofrandomseismicanalysisforlong-spanspatialstructures.(3)Computerprogramsfortherandomvibrationanalysishavebeendeveloped.And random vibration analysis was performed for a long-span canopystructure undermulti-point and multi-dimensional stationery earthquake excitation. Comparisonswere made between multi-dimensional and single-dimensional excitation, uniformexcitation and considering wave passage effect and partial coherence effect, and theresponseswerealsocomparedwhenseismicwavetransmittedindifferentdirections.Some conclusions are given that after considering the wave passage effect ofearthquake motion, the seismic responses vary significantly with the variation of theground apparent wave velocities, and the variation law is very complicated when theapparent wave velocity is low. After the partial coherence effect is considered in therandom seismic analysis of the long-span spatial structures, the random seismicresponses of the partial members near the ground supports, taking pseudo-staticresponses as the primary ones, are increased significantly. But the random seismicresponses of the partial members far from the ground supports, taking the pseudo-dynamic responses as the primary ones, are reduced slightly. When theseismic wave transmits in different directions, the seismic response of the long-spanspatialstructuresisalsodifferent.