Analysis of influence of structural global seismic capacity induced by infills subjected to Wenchuan earthquake

According to the actual survey by seismic damage assessment program for building structures in Dujiangyan City after Wenchuan earthquake, it was found that infills got badly damaged. So firstly, several typical damaged modes of infills and failure mechanisms of infilled frame are introduced and summarized, respectively. Secondly, combining the designed 3 types of infilled frames and actual damaged characteristics of infilled frame in the disaster area, functions and influence of infills to the structure are detailed and emphasized with correlative research. The results show that infills can increase the global bearing capacity, lateral stiffness and deformation capacity of frame structures. However, infills can also lead to weak layer failure and torsion failure due to stiffness effect and short column damage due to confinement effect, which would cause badly damaged to the structure and even collapse. Infills are usually damaged more quickly than frame because of their brittle materials, which can absorb earthquake energy in advance. Therefore, an idea of infills as the first line of defense for the building is advised in the end.