建筑隔震橡胶支座耐火性能和防火保护研究

Research on Fire Resistance and Fire Protection of Seismic Rubber Bearings for Buildings

隔震建筑是近三十年在我国大力发展的新型建筑结构形式.隔震橡胶支座为隔震建筑的重要组成部分,其与承重构件构成基础或层间隔震结构,可降低地震对建筑物的损坏.建筑隔震橡胶支座由钢板和橡胶叠合而成,橡胶为有机材料,所以其支座的持荷能力受温度影响较大.由于隔震支座通常位于柱端部或中部,其为结构关键的承重构件,因此对支座进行耐火性能及防火保护研究十分必要.针对建筑隔震橡胶支座耐火性能,按照《建筑构件耐火试验方法第7部分:柱的特殊要求》(GB/T 9978.7—2008)进行无防火保护支座承重耐火性能试验研究,同时进行数值分析,得到直径为520 mm的隔震橡胶支座的耐火极限时间82 min和耐火极限承载力,并通过极限承载力分析得到无防火保护支座满足耐火性能180 min的尺寸阈值为1000 mm;针对隔震橡胶支座防火保护措施,考虑支座的可动性以及工程适用性,设计两段式组合防火保护方案和柔性防火保护方案,并按照《建筑构件耐火试验方法第1部分:通用要求》(GB/T9978.1—2008)进行非承载的耐火试验研究和相应的数值分析,结果得到两种可动式防火保护方案均满足耐火性能180 min并且隔热性满足支座内部温度均小于橡胶保持力学性能高温阈值150℃的要求.

Isolated buildings are a new type of building structure that has been rapidly developed in China over the past three decades,in which seismic rubber bearings and load-bearing elements form the foundation or floor-isolation structure,which can reduce earthquake damage to the building.Seismic rubber bearings for buildings are composed of steel plates and rubber.As rubber is an organic material,the load-bearing capacity of the bearings is greatly affected by temperature.Seismic rubber bearings are usually located at the end or middle of columns,which are the key loadbearing elements of the structure.Therefore,it is necessary to better understand the fire resistance and fire protection of these bearings.To study their fire resistance,we conducted experiments on seismic rubber bearings without any fire protection or fire resistance,in accordance with GB/T 9978.7—2008 Fire resistance tests—Elements of building construction-Part 7:Specific requirements for columns.The test results and numerical analysis showed that the fire resistance limit time of seismic rubber bearings with a diameter of 520 mm is 82 minutes.We also determined the fire resistance ultimate bearing capacity,which indicated that to realize a fire resistance limit time of 180 minutes,the size threshold of the bearings without fire protection is 1000 mm.To study fire protection measures for seismic rubber bearings,we designed a two-part combined fire-protection scheme and a flexible fire protection scheme,considering the bearing mobility and engineering applicability.Then,we conducted experiments on the fire resistance of non-support bearings according to GB/T 9978.1—2008 Fire-resistance tests—Elements of building construction-Part 1:General requirements.The results of the corresponding numerical analysis showed that both movable fire protection schemes meet the fire resistance limit time of 180 minutes with an internal temperature from the insulation being less than 150℃,which is the threshold temperature of the rubber at which it maintains its mechanical properties.