【作者】 冯鹏；

【导师】 叶列平；

【作者基本信息】 清华大学 ， 土木工程， 2004， 博士

【摘要】 纤维增强复合材料(fiber reinforced polymer,简称FRP)是近年来在土木工程中开始应用的新型结构材料。FRP空心板是一种常用的FRP构件,可用于桥面、墙板和楼面,其中FRP空心桥面板是最具有前景的应用形式之一。本文提出一种新的构造方法,并以此设计制作出一种新型FRP空心桥面板,研究了其静力性能和疲劳性能,研究了其构造增强的机理。论文还对FRP受弯构件的设计理论进行了研究,建议了FRP空心板的设计步骤和方法。由于FRP具有各向异性、非均匀性等材料特性,在FRP空心桥面板中,各组件间连接和截面的构造形式成为影响其力学性能的主要因素。本文首先通过试验,研究了两种FRP空心板的变形性能和破坏特征,总结了文献中各种FRP空心板的破坏特征。在此基础上,提出了一种新的构造方法——外部纤维缠绕增强(outside filament-wound reinforcement,简称OFR),用以增强FRP空心桥面板中各组件间连接的受力性能。试验研究表明,OFR可明显改善其变形能力和承载力,并使破坏过程变缓。随后,通过对已有FRP桥面板构造的研究和对不同截面构造形式的FRP空心板的有限元分析,设计了一种新型FRP空心桥面板——HD板:由2块拉挤面板、4个缠绕芯管以及OFR构成,并经优化设计,最终研制成定型产品。论文进一步对带有不同厚度和不同角度OFR的HD板进行了静载和疲劳试验,试验研究表明:HD板在汽-超20级荷载下满足变形要求,承载力为设计荷载的4倍以上;经过200万次的疲劳加载,构件刚度的变化小于10%。论文还通过有限元分析,研究了OFR在FRP空心板中的作用,揭示了其局部增强和抑止组件间界面裂纹开展的机理。根据FRP与传统结构材料受力性能的差异,论文对受弯构件的性能指标和安全储备问题进行了研究。指出结构安全储备包括:变形储备和承载力储备,并提出4个适用于各类材料的受弯构件的性能指标,以统一考虑变形储备和承载力储备,使FRP构件与传统材料构件具有一致的安全储备。最后,基于本文的试验研究和理论分析,构建了FRP空心板设计分析体系,并为其中各步骤建议了相应的分析计算方法。更多还原

【Abstract】 FRP (Fiber reinforced polymer) is a new structural material in civil engineering in recent years. FRP hollow decks are the typical FRP structure elements, which can act as bridge superstructures, building floor slabs and walls. FRP bridge deck is one of the most promising applications among them. In this research, a new configuration is devised and an innovative FRP bridge deck with this configuration is developed and fabricated. The mechanism of the configuration is analyzed and explained. Furthermore, the design theory of the flexural members is studied. The design procedure for FRP deck is proposed, and the approaches for every step are also suggested.The behavior of FRP deck mainly depends on the connections between the components and the section configuration due to FRP material properties such as orthotropic and heterogeneous. Two types of FRP decks are tested firstly. Their deformation behaviors and failure characteristics are investigated. The failure characteristics of various FRP decks in literatures are also summarized. Based on the researches, the outside filament-wound reinforcement (OFR), a new configuration is put forward, which is expected to strengthen the connections between the components. It is shown in the comparison experiments that the OFR increases the deformation capacity and the strength of the FRP decks and also slow down the failure progress. The existing FRP decks in literatures are investigated, and the different section configurations are analyzed and compared with finite element program. Based on these, an innovative FRP deck with OFR, named HD deck, is developed. HD deck is composed of two pultruded surface plates, four filament-wound core tubes and OFR. The products are fabricated after optimization design. Then, three HD decks with different thicknesses or winding angles of OFR are tested under static load, and one under fatigue load. The tests show that the developed HD decks are satisfied the deformation limitation under the Truck-Load over 20 Degree and their strengths are more than 4 times higher than that of the design load; and further the stiffness of a HD deck after 2 millions of fatigue loading decreases no more than 10% of the original. Furthermore, the acting mechanism of OFR is analyzed with finite element program. It is shown that OFR can provide the restriction to the fracture in the interface of the bonded components and can stiffen the attached plates in local.Due to the differences between FRP and the conventional structural materials, the performance indices and the safety storage of the flexural members are studied. It is indicated that the safety margin are composed of the loading capacity and the deformability safety margin. Four performance indices are presented to describe the loading capacity and the deformability safety margin of various flexural members generally. Moreover by their use, the same safety margin for FRP members and the conventional materials members is obtained. Finally, the design procedure of FRP deck is proposed, and the approach for each step is suggested.更多还原