当复合材料FRP(Fiber Reinforced Polymer/Plastics)筋或拉索应用到斜拉桥的拉索体系时,黏结式锚具和夹片式锚具均有其自身的局限性。对此,根据普通拉索锚固体系的特点,并结合CFRP筋夹片式锚具和黏结式锚具的研究成果,提出了锚固CFRP筋的复合式锚具。复合式锚具由楔紧锚固端和黏结锚固端组成,其中楔紧锚固端包括锚杯、带有凹齿的夹片、铝套管以及塑料薄膜,黏结锚固端包括钢套筒和黏结介质活性粉末混凝土RPC(Reactive Power Concrete)。静载试验研究了锚杯长度、钢套筒长度、夹片预紧力、筋材预张拉力等试验参数对复合式锚具锚固性能的影响。试验结果表明,复合式锚具的试件极限荷载最大为208kN,相应的锚固效率系数为104%,大于95%,满足规范要求。复合式锚具两种锚固形式的锚固长度较合理组合为:对不预张拉锚具,锚杯长度40mm,黏结锚固长度100mm;对预张拉锚具,锚杯长度60mm,黏结锚固长度60mm。提出的复合式锚具极限荷载计算式具有较好的适用性。
When composite material FRP(Fiber Reinforced Polymer/Plastics) tendon is employed in cable-stayed bridges,usage of wedge-type anchor and bond-type anchor for FRP tendons is limited due to their shortcomings. Based on the characteristics of conventional anchorage systems for steel/strands with wedge and bond media,a wedge-bond anchor comprised of wedge anchorage and bond anchorage for CFRP tendons is presented. The wedge anchorage end includes smooth indented wedges,conical barrel,a plastic film,and an aluminum soft metal sleeve,and the bond anchorage end contains steel sleeve and bond medium RPC (Reactive Power Concrete). A series of tests are conducted to comparatively study the bond performance of the anchorage system for CFRP tendons,with different test parameters,including conical barrel length,steel sleeve length,wedge presetting load and pretensioning load. The test results show that the anchorage system can perform well and the ultimate load capability is 208 kN,with the related anchorage efficiency of 104% being larger than 95% and satisfying the code requirements. As for the rational anchor length of the general wedge-bond anchor,the conical barrel length is 40 mm,and the bond length is 100 mm. As for the rational anchor length of the pretensioning wedge-bond anchor,the conical barrel length is 60mm,and the bond length is 60mm. It is demonstrated from the test results that the theoretical solutions for predicting the ultimate capacity of wedge-bond anchors for CFRP tendons are feasible.