纤维增强复材筋增强纤维水泥基复材桥面连接板工作性能研究

INVESTIGATION OF WORKING PERFORMANCE OF FRP REINFORCED ECC LINK SLAB

桥面无缝化设计能够提高桥梁主体结构的耐久性能,是解决桥面伸缩缝维护难题的重要方法。结合高耐腐蚀纤维增强复材(FRP),充分发挥纤维水泥基复合材料(ECC)的高延性。对GFRP筋、BFRP筋和钢筋增强连接板的工作性能、裂缝发展、应变及变形能力进行对比研究,针对GFRP筋连接板设置低配筋率对照组,研究其对整体性能的影响。结果表明,正常服役状态下,连接板最大裂缝宽度均小于限值,满足裂缝宽度要求;钢筋增强连接板的残余变形量远高于FRP增强连接板;FRP筋与ECC较低的刚度差异使得ECC材料多裂缝充分开展;FRP筋连接板主体结构受连接板变形影响较小,且在大变形条件下工作性能良好。依据连接板正常服役筋材应力水平与筋材应力限值,定义连接板正常服役安全系数,定量反映结构构件安全程度。同等配筋率FRP筋增强连接板安全系数均远高于钢筋增强连接板,且GFPR筋配筋率的降低对安全系数影响较小。

The seamless design of bridge deck can improve the durability of the bridge.It is an important method to solve the maintenance problem of bridge deck expansion joints.Combine high corrosion-resistant FRP bars with ECC(Engineering Cementitious Composites)to improve the working performance,multi-crack development of the structure.The strain and deformation ability of FRP and steel bars reinforced link slab were compared,and the different reinforcement ratio of GFRP bars link slabs were conducted.Experiment results show that the maximum crack widths of the link slabs are less than 0.1 mm after the tests,which meet the crack width requirement.However,the residual deformation of the steel reinforced link slab is much higher than that of the FRP reinforced members.It is noticed that the FRP and ECC have the similar elastic modules,which makes the fully multi-crack develop of ECC.The FRP bars have advantages on the deformation of the link slabs due to the batter multi-crack of ECC.The Safety Factor of Link Slab(SFLS)was proposed according to the stress of the link slab reinforcing bars under normal service.Then the safety degree of the structural member is quantitatively reflected.The SFLS of the same reinforcement ratio is much higher than that of the steel reinforcement,and the reduction of the GFPR reinforcement has little effect on the SFLS.