胶合竹梁桥蠕变及承载力试验研究*
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肖岩1,2，李磊1，杨瑞珍1，单波1，佘立永3（1 湖南大学土木工程学院现代竹木及组合结构研究所， 长沙 410082； 2 南加利福尼亚大学土木工程系， 洛杉矶 CA 90089; 3 长沙凯森竹木新技术有限公司， 长沙 410082）［摘要］ 通过对足尺胶合竹梁桥试验模型3年半时间的蠕变观测，得到了10m跨胶合竹CFRP加强桥梁在均布荷载作用下的跨中挠度的长期量测数据，并进行了相关分析。试验结果显示，竹桥3年半的蠕变变形约为7.98mm，且高温和潮湿气候会增加其蠕变速率。对经过3年多蠕变的桥梁进行了静力加载短期破坏试验，在185 kN的均布荷载下，桥梁发生了整体垮塌。试验结果和相关分析表明，CFRP能提高竹梁受力性能，大跨度CFRP加强竹梁能充分满足实际工程中强度和耐久性的需求，但是经过长期受荷之后的竹梁强度和刚度均存在一定程度的下降。研究结果为竹结构桥梁的设计提供了依据，对竹结构桥梁的构造措施也提出了相应的设计建议。［关键词］竹结构; CFRP加强; 桥梁; 长期蠕变试验; 短期荷载破坏试验中图分类号：TU366.3, TU317.1 文献标识码：A 文章编号：1002-848X(2013)18-0086-06Experimental study on creep and loading property of laminated bamboo bridgeXiao Yan1,2, Li Lei1, Yang Ruizhen1, Shan Bo1, She Liyong3(1 Institute of Modern Bamboo Timber and Composite Structure, College of Civil Engineering, Hunan University, Changsha 410082, China; 2 Department of Civil Engineering, University of Southern California, Los Angeles CA 90089, USA; 3 Advanced Bamboo and Timber Technologies Ltd., Changsha 410082, China)Abstract: By monitoring the creep behavior of a full-scale laminated bamboo (glubam) bridge model for three and a half years, the mid-span deflection of 10m CFRP-reinforced glubam girders under evenly distributed loads were obtained and analyzed. The results indicate that the average creep deflection of the girders after three years’ loading is approximately 7.98mm. In addition, the increase in temperature and humidity may contribute to creep. The model bridge was then loaded with evenly distributed load until collapse at an ultimate total load of 185 kN. By analyzing the experimental results, it is realized that CFRP-reinforced glubam girders have sufficient capacity to meet the strength and durability requirements for practical usage. Although CFRP layers could improve the performance of glubam girders effectively, there is a certain degree of decrease in strength and stiffness when considering the long-term performance. The research may contribute to developing future design guidelines of glubam bridge structures, and construction measures were suggested for the bamboo bridge according to the results of the experimental and analysis results.Keywords: bamboo structure; CFRP-reinforced; bridge; long-term creep test; short-term load test*国家自然科学基金重点项目（50938002）。作者简介：肖岩，博士，长江学者特聘教授，博士生导师，Email：yanxiao@hnu.edu.cn。参考文献［1］XIAO Y, ZHOU Q, SHAN B. Design and construction of modern bamboo bridges［J］. Journal of Bridge Engineering, 2010, 15(5): 533-541.［2］单波，周泉，肖岩. 现代竹结构人行天桥中的研发和建造［J］. 建筑结构, 2010, 40(1): 92-96.［3］LEICHTI R J, FALK R H, LAUFENBERG T L. Prefabricated wood composite I-beams: a literature review［J］. Wood and Fiber Science, 1990,22(1): 62-79.［4］TRIANTAFILLOU T C, DESKOVIC N. Prestressed FRP sheets as external reinforcement of wood members［J］. Journal of Structural Engineering, 1992, 118(5): 1270-1284.［5］《木结构设计手册》编委会.木结构设计手册［M］.3版.北京:中国建筑工业出版社,2005.［6］ ASTM D6815-2002a Standard specification for evaluation of duration of load and creep effects of wood and wood-based products［S］. West Conshohocken, PA, USA, 2002.［7］BINDA L. Learning from failure, long-term behaviour of heavy masonry structures［M］. Southampton: WIT Press, 2007.［8］CLOUSER S W. Creep of small wood beams under constant bending load［R］. Forest Products Laboratory Report ，1959.［9］谌润水，胡钊芳. 公路桥梁荷载试验［M］. 北京：人民交通出版社，2003［10］易伟建，张望喜. 建筑结构试验［M］. 北京：中国建筑工业出版社，2008.
