Study On The Seismic Damage Characteristics Of Suspended Ceilings Of Exposed Runners And Mineral Wool Boards

This paper studies the seismic damage characteristics of suspended ceilings with exposed runners and mineral wool boards,which are commonly used in public buildings in China.The main research work is as follows:1)Based on the field investigation results in the 2013 Lushan earthquake,20ceiling specimens whose damage can be completely reconstructed were sorted out.Taking peak floor acceleration as engineering demand parameter,the fragility curves of the"rapid recovery"and"hard to recover"damage states of Chinese suspended ceilings with exposed runners were calculated.It can be known that the seismic performance of Chinese suspended ceilings is weak,and its damage usually happens at edges and corners.It is also pointed out that when the peak floor acceleration is about1.1g,there is a 50%probability that the ceilings will reach or exceed the"hard to recover"damage state.2)The seismic performance of suspended ceilings with exposed runners and mineral wool boards under simple harmonic vibration and ground motions were investigated by shaking table test,and the influence of vibration characteristics including peak acceleration,peak velocity,loading frequency and vertical loading were also investigated.It is found that there is no obvious relationship between peak acceleration or peak velocity and the falling ratio of ceilings.The horizontal floor acceleration response spectrum corresponding to S_ay?T_s=0.2s?and the vertical floor acceleration response spectrum value corresponding to S_az?T_s=0.1s?have a significant influence on the damage of ceiling specimens.Vertical vibration can significantly aggravate the destruction of ceilings,and grid failure mainly happens due to horizontal vibration.3)The influence of structural measures such as runner supporting condition,splay wires and suspension distance on the seisimic performance of ceilings was investigated in the shaking table test.When the ends of main runners were fixed,the damage of ceilings was obviously reduced.Splay wire didn't reduce the damage of ceilings,but aggravated the damage to some extend.The suspension distance has no obvious influence on the ceiling failure.4)The numerical model of ceiling specimens in shaking table test is built in OpenSEES.The friction and impact behavior between ceiling tiles and runners were considered in this model.Comparing numerical analysis results with test results,it is found that the model can accurately simulate the relative displacement of ceiling tiles,the relative displacement between ceiling tiles and main runners and the acceleration of the main runners.