膠合竹梁橋蠕變及承載力試驗研究*
肖巖1,2，李磊1，楊瑞珍1，單波1，佘立永3
- 摘 要
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肖巖1,2，李磊1，楊瑞珍1，單波1，佘立永3（1 湖南大學土木工程學院現(xiàn)代竹木及組合結(jié)構(gòu)研究所， 長沙 410082； 2 南加利福尼亞大學土木工程系， 洛杉磯 CA 90089; 3 長沙凱森竹木新技術(shù)有限公司， 長沙 410082）［摘要］ 通過對足尺膠合竹梁橋試驗?zāi)Ｐ?/span>3年半時間的蠕變觀測，得到了10m跨膠合竹CFRP加強橋梁在均布荷載作用下的跨中撓度的長期量測數(shù)據(jù)，并進行了相關(guān)分析。試驗結(jié)果顯示，竹橋3年半的蠕變變形約為7.98mm，且高溫和潮濕氣候會增加其蠕變速率。對經(jīng)過3年多蠕變的橋梁進行了靜力加載短期破壞試驗，在185 kN的均布荷載下，橋梁發(fā)生了整體垮塌。試驗結(jié)果和相關(guān)分析表明，CFRP能提高竹梁受力性能，大跨度CFRP加強竹梁能充分滿足實際工程中強度和耐久性的需求，但是經(jīng)過長期受荷之后的竹梁強度和剛度均存在一定程度的下降。研究結(jié)果為竹結(jié)構(gòu)橋梁的設(shè)計提供了依據(jù)，對竹結(jié)構(gòu)橋梁的構(gòu)造措施也提出了相應(yīng)的設(shè)計建議。［關(guān)鍵詞］竹結(jié)構(gòu); CFRP加強; 橋梁; 長期蠕變試驗; 短期荷載破壞試驗中圖分類號：TU366.3, TU317.1 文獻標識碼：A 文章編號：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*國家自然科學基金重點項目（50938002）。作者簡介：肖巖，博士，長江學者特聘教授，博士生導(dǎo)師，Email：yanxiao@hnu.edu.cn。參考文獻［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］單波，周泉，肖巖. 現(xiàn)代竹結(jié)構(gòu)人行天橋中的研發(fā)和建造［J］. 建筑結(jié)構(gòu), 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］《木結(jié)構(gòu)設(shè)計手冊》編委會.木結(jié)構(gòu)設(shè)計手冊［M］.3版.北京:中國建筑工業(yè)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］諶潤水，胡釗芳. 公路橋梁荷載試驗［M］. 北京：人民交通出版社，2003［10］易偉建，張望喜. 建筑結(jié)構(gòu)試驗［M］. 北京：中國建筑工業(yè)出版社，2008.
