（1 建发房地产集团有限公司， 厦门 361008； 2 上海市建筑科学研究院上海市工程结构安全重点实验室， 上海 200032；  3 东南大学建筑设计研究院有限公司， 南京 210096）

［摘要］通过2组7根胶合木梁三面受火后力学性能的对比试验，研究了不同表面处理和不同受火时间后胶合木梁的破坏形态、剩余承载力和应变的变化规律。研究表明，胶合木梁剩余承载力随受火时间增加而明显降低，受火20～40min后剩余承载力显著降低；表面有阻燃涂料处理试件剩余承载力略大于无阻燃涂料处理试件。未受火对比试件和受火后试件跨中截面应变分布均符合平截面假定；相同荷载作用下，受火后试件梁底和梁顶的应变均大于未受火对比试件。采用基于ABAQUS二次开发的木材本构模型，能准确预测木材内部温度在100℃左右时的平台段，且距离受火面越远平台段越长；水平和竖向炭化深度模拟值与试验值误差为8.6%～14.0%，能较准确地模拟胶合木梁的炭化深度； 胶合木梁受火后剩余承载力模拟值与试验值吻合较好，可用于胶合木梁三面受火后剩余承载力的评估。

［关键词］木结构； 胶合木梁； 三面受火；  阻燃涂料； 炭化深度； 剩余承载力

中图分类号：TU352-5， TU366-3文献标识码：A文章编号：1002-848X(2020)16-0087-07

Experimental study of the mechanical behavior of glulam beams exposed to three-side fire

HU Xiaofeng1, CHEN Lingzhu2, XU Qingfeng2, HAN Chongqing3, LENG Yubing2

(1 C&D Real Estate Corporation Limited, Xiamen 361008, China;2 Shanghai Key Laboratory of Engineering Structure Safety, SRIBS, Shanghai 200032, China;3 Architects & Engineers Co., Ltd. of Southeast University, Nanjing 210096, China)

Abstract:The failure mode, residual bearing capacity and strain of 7 glulam beams in 2 groups after exposed to three-side fire were experimentally studied under different fire retardant coating and exposed time. The results show that the residual bearing capacity of glulam beams decreases obviously with the exposed time increasing from 20 minutes to 40 minutes, and the residual bearing capacity of glulam beams with fire retardant coating is slightly bigger than that of exposed specimens without fire retardant coating. The strain distribution in middle cross-section of unexposed and exposed specimens accord with the plane section assumption. Under the same load, the strain at the top and bottom surface of exposed specimens are bigger than the unexposed specimen. Through the secondary development of wood constitutive model based on software ABAQUS, the phenomena that the temperature of wood had a slow growth platform at around 100℃, and the longer the distance from the exposed surface, the longer the platform was can be accurately predicted. The horizontal and vertical charring depth can be accurately predicted, and the error between simulated and test results were 8.6%~14.0%. The simulated results of residual bearing capacity of glulam beams agree well with the test results. The model can accurately evaluate the residual bearing capacity of glulam beams after exposed to three-side fire.

Keywords:timber structure； glulam beam; exposure to three-side fire; fire retardant coating; charring depth; residual bearing capacity

*国家自然科学基金（51808339），上海市青年科技启明星计划项目（17QB1403400）。

通讯作者：许清风，博士，教授级高级工程师，Email: xuqingfeng73@163.com。