摘要
提出一种由冷弯薄壁C型钢托梁-轻质配筋蒸压加气混凝土板(ALC板)组合楼盖,并设计完成了6片该类组合楼盖足尺模型耐火试验,考察了吊顶类型、填充层、荷载水平等因素对组合楼盖耐火性能的影响。研究结果表明:1)当组合楼盖空腔岩棉填充层不依靠吊顶板材即可固定于相邻托梁龙骨之间时,填充层对组合楼盖耐火起有利影响;带35 mm厚岩棉填充层的组合楼盖试件在2.0 k N/m2荷载水平下,耐火极限较类似构造的无填充层楼盖延长10.6%,达到83 min。2)组合楼盖耐火极限随荷载水平降低呈增大趋势,其中,采用双层防火石膏板吊顶的冷弯薄壁型钢组合楼盖试件,当荷载水平由5.0 k N/m2降至2.0 k N/m2时,耐火极限由65 min延长至75 min。3)组合楼盖的托梁龙骨受火屈曲破坏模式与楼盖荷载水平及吊顶构造无明显关联,表现为半波长为螺钉间距的跨中上翼缘高温畸变屈曲同时伴随相邻腹板、卷边高温局部屈曲破坏。4)玻镁板具有明显优于防火石膏板的耐火性能,空腔无填充层的单层15 mm玻镁板吊顶的组合楼盖试件在2.0 k N/m2荷载水平下,耐火极限达到84 min。组合楼盖试件均满足我国规范的多层民用建筑耐火极限要求。
A new CFS C-shape joists-ALC（ autoclaved lightweight concrete） composite floor was developed. A detailed experimental investigation on six full-scale composite floor assemblies was carried out. The effects of different type of ceilings,insulation and load levels etc. were also investigated. The results show that： 1） the existence of insulation would improve the fire performance of composite floors if the insulation which is laid between the adjacent joists can keep its position during the construction without falling off and the helping of ceiling panels; the fire resistance of present floor assembly under the load level of 2. 0 k N / m2 is extended by 10. 6% and reaches 83 minutes by the utilization of 35 mm rock wool insulation; 2） the fire resistance time of composite floor would increase with the decreasing of load levels; the fire resistance of present floor assemblies changes from 65 minutes to 75 minutes by the decreasing of load level from 5. 0 k N / m2 to 2. 0 k N / m2; 3） the failure modes of CFS joists seems to have no correlation with the ceiling configuration and load levels of composite floors under fire conditions; during the fire experiments,the distortional buckling of top flange combined with local buckling of adjacent lip and web occurred at the mid-span of joists; 4） the fire performance of bolivian magnesium board is superior to that of the fire resistant gypsum plasterboard,the assembly ceiled with only single layer of 15 mm bolivian magnesium board and no cavity insulation reaches 84 minutes under the load levels of 2. 0 k N / m2. All the present composite floor assemblies has met the fire resistance requirement for mid-rise buildings in China.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2015年第8期108-115,共8页
Journal of Building Structures
基金
国家科技支撑计划(2011BAJ08B04)
中国矿业大学土木工程环境灾变与结构可靠性江苏省重点实验室开放基金项目(JSKL2014K04)
关键词
冷弯薄壁型钢组合楼盖
玻镁板
吊顶构造
荷载水平
足尺耐火试验
耐火极限
cold-formed steel composite floor
bolivian magnesium board
ceilings configuration
load level
full scale fire experiment
fire resistance time
