刘君+周朝阳+韩殿牧原+赵波涌+任达

摘要：针对传统纯粘贴纤维增强复合材料（FRP）抗剪加固钢筋混凝土梁技术中，FRP强度利用率低、端部极易发生剥离和被动受力等问题，自主研发了抗剪加固用U形纤维布条带预应力系统.它由锚固装置、张拉装置和转角圆钢3部分组成.详细给出了各部件尺寸的设计方法和预应力施工工艺.设计制作了适用于2层50 mm宽FRP的预应力系统，分别进行了1组直线条带的承载力试验和8组抗剪U形条带的预应力损失试验研究.结果表明：预应力系统能够有效锚固FRP并实现拉断破坏，使其强度利用率最大可达到96.1%；各部件尺寸设计方法是安全可靠的；施工工艺能够在确保FRP两侧应力的均匀性和对称性的基础上施加不同大小的预应力值；预应力系统适用于施加244.84 MPa以上预应力值的抗剪FRP，其长期预应力损失比约为15%.

关键词：预应力系统；U形纤维布；抗剪加固；锚固；预应力损失

中图分类号：TU375；TU317 文献标识码：ADesign and Experiment Study of Prestressing System

3. School of Civil Engineering， Guangzhou Univ， Guangzhou， Guangdong510006， China）Abstract： In the shear strengthened reinforced concrete （RC） beams by externally bonded fiber reinforced polymer （FRP） composite， there are some main shortcomings including low fiber utilization， premature debonding， and stress hysteresis of the FRP， etc. In order to address these problems， this paper independently developed a novel prestressing system for Ushaped FRP sheet in shear strengthening， which consists of three parts： anchor device， tension device， and steel angle. The design method of component size and the prestress construction technology were presented. Furthermore， a prestressing system for 2ply and 50mmwide FRP sheet was designed and manufactured. One bearing capacity test of linear FRP sheet and eight prestressing loss tests of shearstrengthened FRP strips were conducted in this system. The test results show that： the prestressing system can effectively anchor FRP and result in rupture failure； fiber strength increases up to 96.1%； design method of component size is safe and reliable； prestressing construction technology can exert different prestress values to FRP strip based on the uniformity and symmetry of the strip stress； the system is applicable to exert the prestress more than 244.84 MPa to the FRP； and the longterm prestress loss ratio is about 15%.

Key words： prestressing system； Ushaped FRP sheet； shear strengthening； anchorage； prestress loss

由于材料老化、環境侵蚀、设计失误、施工出错、功能改变等因素，当混凝土梁抗剪承载力不足，或抗弯加固后梁的抗剪承载力小于抗弯承载力时，就需要进行抗剪加固[1].采用纤维增强复合材料（FRP）片材对混凝土梁进行抗剪加固是目前最常用的形式之一.

湖南大学学报（自然科学版）2016年第11期刘君等：抗剪加固用U形纤维布条带预应力系统设计及试验虽然FRP传统纯粘贴方法简便易行且应用广泛[2-3]，国内外也制定了相关技术标准规范[4-5]，但是……