Research And Control On Entire Failure Modes Of Masonry Structure With Ring Beams

Masonry structure is one of the common structure forms in our country.According to the investigation of the damage in recent years, the common destruction of masonry wall is the failure mode of the wall between windows and the failure mode of the spandrel wall. The traditional structural design theory of masonry structure is the default mode of the wall between windows, which does not consider the damage of the spandrel wall and its benefits. Firstly, the failure of the spandrel wall can consume a part of the earthquake energy in advance, reducing the failure of the wall between windows. Secondly, the failure of the spandrel wall will not cause the collapse of the entire structure. It can delay the collapse of the structure, which is ductile failure.Furthermore, the damage of the spandrel wall has the advantages of rapid repair and convenient construction, but the failure mode of the spandrel wall is not considered in the structural design. Therefore, on the basis of the effect of ring beam on the seismic performance of masonry structures and failure, consider setting ring beam of masonry structure under the window wall failure mode design method, the main research work carried out as the follows:Based on researches and analysis of the earthquake damage of Wenchuan earthquake disaster area, three typical entire failure models of masonry structures are summed up by studying team.Through the comparison and analysis of various failure modes, an ideal failure mode that window belly wall with high energy dissipation and good ductility damage before window pier wall is put forward.By means of the finite element software ABAQUS, the wall dangerous point under seismic action first appeared in wall section core region and its vicinity and the shear failure occurred.By finite element technology, the effect of ring beam on seismic performance and failure modes of masonry structure wall is compared and analyzed,ring beam can not only improve the seismic performance but it also significantly delay window belly wall failure for masonry structure.In addition, analysis of failure mode and the difference of elasto-plastic time-history for masonry structure with or without ring beam is conducted, leading to a conclusion that ring beam can reduce the degree of structural failure and delay the moments of the emergence and serious damage of window belly wall damages, which fully reveals that the ring beam have an important influence on the seismic performance of masonry structure and failure pattern.Based on the delaying effect of ring beam on the failure modes of window belly wall for masonry structure, quantitative analysis that the impact of ring beam on shear bearing capacity of window belly wall is developed, the ring beam has played an indelible role in the bearing capacity of window belly wall.The basic form of seismic bearing capacity calculation formula of window belly wall with ring beam has been initially identified. The optimal values ofCη andc? are obtained by using the principle of least square method,and the seismic bearing capacity design method of window belly wall with ring beam has been initially identified.Based on the strong column and weak beam design idea, an ductile failure mode control method that window belly wall damage before window pier wall is put forward, which conforms to the seismic fortification goal of multiple lines according to the anti-seismic designing code.This method provides a reference for the improvement of the seismic design of masonry structures and the realization of the ideal failure mode under strong earthquake.