Seismic Performance Of Key Joint In Mineral Wool Board Suspended Ceiling

In recent years,seismic damages have occurred frequently all over the world.Even if the structures are sound after the earthquakes,there are still serious direct and indirect economic losses caused by the damages of the non-structural elements.Partial or complete interruption of the functional parts of important buildings will hinder rescue and relief work.Therefore,it is important to study the seismic performance of the non-structural elements.Suspended ceiling is a typical non-structural element of buildings.It not only has the function of decorating the indoor space and improving the indoor environment,but also acts as the hidden layer for the pipelines of devices,such as illumination,ventilation,fire protection,etc.If a suspended ceiling is damaged in earthquakes,not only the non-structural elements connected to it will be affected,but also the crowds will be panic and emergency rescue will be influenced.In this study,the mineral wool board suspended ceiling has been investigated.It has been mainly used in public places,such as schools,hospitals and stores.So far,there has been little research specifically on the seismic performance of the mineral wool board suspended ceiling.In an earlier investigation of earthquake damage,the seismic damage of the mineral wool board suspended ceiling was found to be extremely serious,it is necessary to study its seismic performance.Hence,the tasks of this study are as follows:1.Through a summary of seismic damage data of the suspended ceiling,this study identifies the common seismic damage types of mineral wool board suspended ceilings.On this basis,the test results of domestic and overseas suspended systems are analyzed,and the main factor to cause the severe seismic damage of suspended ceilings.Furthermore,this study analyzes the failure mechanism and identifies the seismic vulnerable spots combing the construction technology of mineral wool boardsuspended ceilings.2.According to the identified seismic vulnerable spots that are easy to fail,a testing program has been formulated.The seismic performance test has been conducted on the main-cross runner joints in the horizontal direction and the main runner-hook joints in the vertical direction.Based on the results,it has been concluded that the failure load of the main-cross runner joints is highly dependent on the bending degree of the cross runner connection end and the probability that the lugs on the connection end are stuck together.And the failure load of the main runner-hook joints is highly dependent on the length and path of cutting line of the hook and the connection end of main runner webs.3.According to the analysis results of the seismic performance test of key joint in mineral wool board suspended ceiling,the detail structures of the ceiling grids joints in the test has been improved.The probability that the lugs on the secondary joist connection end of main-cross runner joints that are stuck together has increased,and the eccentricity and torsion effect of hook in the main runner-hook joints have decreased.Further,the joint strengthening construction measures that are easy to process and install are recommended to be used as the main(cross)runner-Closure angle joints.The seismic performance of mineral wool board suspended ceiling joints has improved through the rational and effective seismic construction measures.Hence,the losses caused by seismic damage of mineral wool board suspended ceilings have reduced.