石灰膏抹面木梁受火后受力性能静力试验研究  

Static experimental research on mechanical behavior of timber beams with lime putty finishing after fire

作　　者：许清风[1,2] 李向民[1,2] 穆保岗[3] 张晋[3] 徐明[3] 李帅希[3] 

机构地区：[1]上海市工程结构新技术重点实验室,上海200032 [2]上海市建筑科学研究院,上海200032 [3]东南大学土木工程学院,江苏南京210096

出　　处：《建筑结构学报》2011年第7期73-79,共7页Journal of Building Structures

基　　金：上海市科委青年科技启明星计划(07QB14031);上海市科委青年科技启明星跟踪计划(11QH1402100);国家"十一五"科技支撑计划(2006BAJ03A10-02)

摘　　要：木梁受火后由于炭化作用将使其有效截面减少、承载能力降低。通过2组11根木梁三面受火后力学性能的对比试验研究,分析了石灰膏抹面对木梁火灾性能影响。研究结果表明:对比木梁、三面受火无石灰膏抹面木梁和三面受火有石灰膏抹面木梁的破坏形态基本相似;三面受火30min的石灰膏抹面木梁由于含水率降低且木材未遭受炭化损伤,其承载力反而有所提高;石灰膏抹面三面受火木梁的跨中截面变形基本符合平截面假定;石灰膏抹面能显著延缓三面受火木梁内部温度的升高速率,降低外部火场温度的不利影响;有效降低三面受火木梁初始炭化时间,显著降低炭化速度;石灰膏抹面能有效提高三面受火木梁的耐火极限。The effective cross-sectional area and the bearing capacity of timber beams exposed to fire will drop because of the charring of wood.To learn the benefit of lime putty finishing to fire performance,two groups of 11 timber beams were experimentally studied.It is found that the failure modes of the control specimen,the timber beams exposed to 3-side fire and the timber beams with lime putty finishing exposed to 3-side fire are almost the same.The bearing capacity of timber beams with lime putty finishing exposed to fire for 30min is obviously increased because of the decrease of the moisture content and no charring.During the loading phase,the strain profiles of the mid-span cross-section of exposed timber beams are nearly linear.The lime putty finishing can obviously reduce the increase gradient of the temperature inside the timber beams,effectively delay the beginning time of charring and decrease the charring rate.The fire duration will extend after lime putty finishing is burnt up.

关 键 词：木梁 石灰膏抹面 受火试验 静力试验 力学性能 炭化速度 

分 类 号：TU366.2[建筑科学—结构工程] TU317.1