Experimental studies of the seismic behavior of double-layer lattice space structures I: Experimental verification

Abstract

Abstract Double-layer lattice space structures were found in a severe state of damage following the 2013 M7.0 Lushan earthquake in China. The failure of this kind of structure can result in huge damage and extensive repair costs. Therefore, the accurate definition of degrees of structural damage in double-layer lattice space structure is of high interest, in particular to give a better understanding of failure mechanisms and more accurately implement performance-based designs of these structures. In this paper, typical failure patterns of two gymnasiums are summarized, and possible reasons are broadly discussed. The seismic behavior of a double-layer lattice space structure with a lower supporting structure was then investigated using a shaking table test. To this end, a 1/10 scale model of a double-layer lattice space structure corresponding to the prototype structure with span of 40.8 m was designed. The dynamic characteristics including structure frequencies and damping ratio were obtained through the results under the input excitation of white noises with different amplitudes. Furthermore, two representative earthquake records were used to evaluate the performance and different damage degree by a 5 m × 5 m shaking table. The seismic responses including the acceleration and displacement placed at different height of the model as well as the strain gathered at the members were discussed. Results of the test indicate that the seismic effect is underestimated without considering the dynamic amplification effect of the lower supporting structure, which leads to the failure of structures. Therefore, the lower supporting structure should be considered as an integrated model with the upper structure when conducting seismic analysis and evaluation, rather than considering the lower supporting structure as rigid.