An 80 magnitude earthquake attacked the northwestern margin of the Sichuan Basin on May 12

2008. A large number of buildings suffered damage to different degree in the epicenter regions. Sichuan University reconnaissance team investigated the performance of residential masonry structure buildings with ground R.C. frame for commercial purpose following the Earthquake. This kind of structure style is widely taken in the epicenter area. Many of them suffered severe damage or even collapsed totally

however

some of them had perfect performance during the Earthquake. Many structural deficiencies and mistakes were highlighted

which including excessive horizontal displacement in the ground

more severe damaged transition layer (the first masonry structure layer)

ground with farraginous structure

and poor construction quality. Finally

lateral stiffness ratio of the second to ground story in masonry buildings with RC frame structure at the bottom will be optimized following difference of materials between the ground floor and the upper floors. The strength and the ductility of transition layer

as well as shear walls in the ground floor

are crucial to keep the building standing during large earthquake. 