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許清風(fēng)^1,2，張晉³，商景祥³，李向民^1,2，李維濱³

（1 上海市工程結(jié)構(gòu)新技術(shù)重點(diǎn)實(shí)驗(yàn)室，上海 200032；2 上海市建筑科學(xué)研究院（集團(tuán)）有限公司，上海 200032；3 東南大學(xué)混凝土及預(yù)應(yīng)力混凝土結(jié)構(gòu)教育部重點(diǎn)實(shí)驗(yàn)室，南京 210096）

 

[摘要] 受火木梁耐火極限判別需綜合考慮跨中撓度和跨中撓度變化率。通過2組共7根木梁三面受火的對(duì)比試驗(yàn)，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極限。研究結(jié)果表明，根據(jù)跨中撓度和跨中撓度變化率綜合判定，試件B100P25，B100P37.5，B100P50的耐火極限分別為23，17，12min，試件B150P50，B150PC50的耐火極限分別為37，48min。即隨著持荷水平增加，三面受火木梁耐火極限明顯降低；隨著截面尺寸增加，三面受火木梁耐火極限顯著增加；在木梁表面涂抹防火涂料后，三面受火木梁耐火極限亦明顯提高。

[關(guān)鍵詞] 木梁；三面受火；耐火極限；跨中撓度；變化率

中圖分類號(hào)：TU366.2，TU352.5     文獻(xiàn)標(biāo)識(shí)碼：A     文章編號(hào)：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啟明星跟蹤計(jì)劃（07QB14031,11QH1402100），國家自然科學(xué)基金（51178115）

作者簡(jiǎn)介：許清風(fēng)，博士，高級(jí)工程師，Email:qingfengxu@yahoo.com.cn

 

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