Seismic Damage Analysis And Design Suggestions On Brick Masonry Buildings

A violent earthquake with the seismic intensity of 8.0 happened in May 12 2008, known as Wenchuan earthquake in Sichuan Province. A large number of buildings were damaged during the earthquake, especially the masonry buildings .The damage area of masonry buildings accounts for 80% of the total damage area, which brings great difficulties to the rescues.Code for seismic design of buildings (GB50011-2001) stipulates that for long-span structure, long cantilever structure, chimney and similar structure in the seismic area of 8 and 9 degree, high-rise building in the seismic area of 9 degree, the effect of vertical earthquake should be considered. But for masonry structure, it is not clear. In order to solve this problem, this paper sorts and concludes the typical damage of masonry structure in Wenchuan earthquake and explains the importance of the role of consideration on vertical seismic in the process of masonry structure design by analyzing the cause of damage.Based on the acceleration records got from the Wenchuan Earthquake as well as domestic and abroad earthquakes happened in the recent ten years, the relationship between vertical earthquake acceleration and horizontal earthquake acceleration under different seismic fortification intensity and classification of design earthquake are given. According to the relationship, the value of vertical earthquake force under different seismic design intensity is figured out by adopting the impulse method. And the analysis for vertical seismic force distribution as well as its impact on the masonry structure is operated. Moreover, in order to avoid collapse of building and the local compression damage at a certain floor, the ultimate axial compression ratio of the masonry wall is given. It will play a positive role on improving the masonry structure's earthquake resistance.According to ultimate axial compression ratio of the masonry wall, the actual axial compression ration for the existing building is checked, and the corresponding measures are given to those houses that can not meet the requirements. As to the masonry buildings damaged in the earthquake but still having the value of repairing, the residual carrying capacity is given based on different damage conditions. The reinforcement measures are given after considering the effect of vertical earthquake, which not only ensure that the building meets the requirement of service, but also ensure the safety of the building under the rare earthquake after reinforcement.