许清风^1,2，张晋³，商景祥³，李向民^1,2，李维滨³

（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（集团）有限公司，上海 200032；3 东南大学混凝土及预应力混凝土结构教育部重点实验室，南京 210096）

 

[摘要] 受火木梁耐火极限判别需综合考虑跨中挠度和跨中挠度变化率。通过2组共7根木梁三面受火的对比试验，研究不同截面尺寸、不同持荷水平、是否采用防火涂料的三面受火木梁的耐火极限。研究结果表明，根据跨中挠度和跨中挠度变化率综合判定，试件B100P25，B100P37.5，B100P50的耐火极限分别为23，17，12min，试件B150P50，B150PC50的耐火极限分别为37，48min。即随着持荷水平增加，三面受火木梁耐火极限明显降低；随着截面尺寸增加，三面受火木梁耐火极限显著增加；在木梁表面涂抹防火涂料后，三面受火木梁耐火极限亦明显提高。

[关键词] 木梁；三面受火；耐火极限；跨中挠度；变化率

中图分类号：TU366.2，TU352.5     文献标识码：A     文章编号：1002-848X(2012)12-0127-04

 

Xu Qingfeng ^1,2, Zhang Jin³,  Shang Jingxiang³,  Li Xiangmin ^1,2,  Li Weibin³

(1 Shanghai Key Laboratory of New Technology Research on Engineering Structure, Shanghai 200032, China; 2 Shanghai Research Institute of Building Sciences (Group), Co., Ltd., Shanghai 200032, China; 3 Southeast University, Key Laboratory of C & RC Structures of Ministry of Education, Nanjing 210096, China)

 

Abstract: The fire endurance of timber beams is determined not only by the mid-span displacement, but also by the changing rate of mid-span displacement. To learn the effective factors of fire endurance such as load level, cross-section and fire retardant coating, 7 specimens of 2 series were experimentally studied. The results show that, according to mid-span displacement and changing rate of mid-span displacement, the fire endurances of B100P25, B100P37.5 and B100P50 are 23, 17, 12min respectively, and the fire endurances of B150P50 and B150PC50 are 37 and 48min. The fire endurance of the timber beam exposed to three-side fire has an obvious decrease when the load level increases, has a prominent increase when the corss-section increases, and also has an obvious increase when the fire retardant coating is used.

Keywords: timber beam; three-side fire; fire endurance; mid-span displacement; changing rate

*上海市科委青年科技启明星跟踪计划（07QB14031,11QH1402100），国家自然科学基金（51178115）

作者简介：许清风，博士，高级工程师，Email:qingfengxu@yahoo.com.cn

 

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