Analysis of factors influencing dynamic characteristics of building structures on slope

The most outstanding characteristic of the building structures on slope is that the structure is supported on foundations with different horizontal levels. The mechanical properties of this type of structure are different from those of the structure supported on foundation within same horizontal level. The dynamic characteristics of such building structures were studied in this paper. Considering the lateral story stiffness, story masses, and story numbers between different foundation levels, the natural frequencies, natural mode shapes, modal participation factors and modal participating mass ratios were analyzed. The influences of the three factors above-mentioned on the dynamic responses were investigated by comparing the seismic responses of four prototype frame structures on slope. The results show that, for building structures on slope, the first vibration mode mainly influences the responses of the upper Stories, while the higher modes have more contribution to the responses of the lower stories. As a result, more vibration modes should be considered in such structural seismic design to avoid underestimating structural responses.