Coherency Model For Spatially Varying Ground Motions And Influence On Single-layer Reticulated Domes

With the rapid development of economy in our country, a large number of long-span space structures have been built, which are regarded as landmarks and sheltersafter the earthquake for the cities or areas. Therefore, their safety and anti-seismiccapacity has attracted special attention of researchers. In current anti-seismic analysis,simple support excitation is widely adopted to solve the seismic response of thestructures, which is unreasonable for long-span structures. Although multiple supportexcitations considering spatial correlation is in line with the actual seismic waves input,theoretical system about multiple support excitations has not formed yet. Starting withthe research on the coherency function which can well describe spatially varying groundmotion between two points, this thesis simulates non-stationary ground motion andanalyzes the influence of multiple support excitations on long-span space structures.The thesis consists of the following sections:1. Based on a large number of practical dense array records obtained by LSST andSMART-1array, spatial variability for three components of ground motion wasanalyzed. Coherency model for the distance range of3m to4000m was built up throughstatistical regression, which is suitable to describe ground motion spatial variabilitywhen the distance between the adjacent supports of span structures is smaller.Considering the impact of source characteristics, the selection principle of coherencymodel was put forward.2. On the basis of coherency function model established in this paper, the non-stationary ground motion was simulated, and its reliability was verified throughcomparative analysis with the actual ground motion. Then using whole process analysismethod in the load domain, time history analysis of Kiewitt8single-layer reticulateddomes with a span of80m under simple support excitation and multiple supportexcitations in one dimension, and under simple support excitation and multiple supportexcitations in three dimensions was completed. The result shows that spatial variabilityhas a great influence on the single-layer reticulated shells, so it is dangerous for seismicdesign using simple support excitation.3. Ground motion respectively considering incoherence effect, wave-passage effectand their coupling effects was simulated, and the structural responses under groundmotion input above were derived. The influence that different effects under multiplesupport excitations had on the structure was analyzed in comparison with the structuralresponse under simple support excitation.