摘要
木材是可燃性材料,研究木构件的抗火性能具有重要意义。由于缺乏木结构耐火性能的系统研究,我国现行国家标准《建筑设计防火规范》和《木结构设计规范》基于试验方法,仅给出了各类木构件耐火极限的要求,未给出其计算方法。分别介绍了欧洲规范、美国规范、澳洲规范和加拿大规范的木梁耐火极限计算方法,对比发现各国规范中木梁耐火极限计算方法均基于剩余截面法,但其中木材炭化速度的计算方法不同,且考虑角部倒角效应及温度影响区的范围不同。通过将各国规范耐火极限预测值与试验结果对比,发现基于剩余截面法的木梁耐火极限计算方法能较好地预测木梁的耐火极限,考虑密度对炭化速度影响的欧洲规范和澳洲规范与试验结果更接近,因此建议我国规范中木梁耐火极限计算采用考虑密度影响的剩余截面法。
Timber is combustible material. Study on the fire performance of timber members is of great significance. Due to the lack of the systematic study on the fire performance of timber structures, current codes, Code for fire protection design of buildings （GB 50016-2014） and Code for design of timber structures （GB 50005-2003）（2005 version） in our country are based on the tests, only the required fire rate of each type of timber members is stated in these code and the calculation methods to determine the fire rate of these members are missing. This paper introduces the calculation methods for fire rate of timber beams in Eurocode, American code, Austral- ia code and Canadian code. It was found from the comparison between these codes that all these methods are based on residual cross-section method, but the ways to calculate the charring rate and the effect of corner roundings and thermal influence zone are different. Comparisons between the predicted fire rate from these codes and test reults show that the calculation methods for fire rate of timber beams based on residual cross-section method are able to predict the fire rate of timber beams with high accuracy, and the predictions of Eurocode and Australian code which include the effect of density of wood species are closer to test results. Thefore, the calculation methods based on residual cross-section method considering the effect of density of wood species was recommended to employ in Chinese code.
出处
《防灾减灾工程学报》
CSCD
北大核心
2016年第3期399-404,共6页
Journal of Disaster Prevention and Mitigation Engineering
基金
上海市优秀技术带头人计划项目(15XD1522600)
国家自然科学基金项目(51178115)
上海市工程结构安全重点实验室开放课题项目(2013-KF04)资助
关键词
木梁
耐火极限
剩余截面法
防火设计
炭化速度
timber beams
fire rate
residual cross-section method
fire design
charring rate
