基于新型预应力CFRP技术梁板柱关键结构研究

Research on Key Structures of Beams,Slabs and Columns Based on New Prestressed CFRP Technology

CFRP(碳纤维复合材)材料轻质高强,抗拉强度可达3000MPa及以上,并且具有良好的抗环境性能,而且施工操作比较简单,近年来在土木工程梁、板、柱结构的加固中获得了广泛应用。普通粘贴CFRP片材不能发挥材料的抗拉强度,这不仅缘于混凝土梁的裂缝限制,也受到挠度的限制,还受到在裂缝两侧、CFRP片材两端的高粘结剪应力导致的剥离破坏的限制。由于粘贴操作时不做卸载处理或难以进行卸载,正常使用状态下粘贴的CFRP布并不参与受力,因此对改善结构使用性能几乎不起作用。普通粘贴的CFRP布只有在超载条件下才会参与受力,但由于应变滞后以及弹性模量与钢筋相当或低于钢筋等原因,裂缝宽度限值条件下CFRP片材能发挥的应力水平一般只有材料强度标准值的1/20左右或略高。本项目提出的高效后张CFRP板预应力桥梁结构加固系统,以CFRP板为预应力加固材料,通过预张拉,使CFRP板在正常使用状态下即处于较高应力状态(不低于1000MPa),从而改善桥梁结构正常使用性能水平;通过预张拉,减小各种载荷条件下的粘结剪应力,降低剥离破坏风险,确保CFRP板与基体混凝土结构协同工作;在承载能力极限状态下,能够充分发挥材料的抗拉强度,提高材料利用率;利用CFRP板端部锚具,彻底解决CFRP材料端部剥离破坏现象,确保CFRP板加固的可靠性;通过完善锚具设计和张拉工艺设计,使CFRP板预应力加固在房屋、桥梁等梁、板、柱关键结构研究领域获得广泛应用,推动技术进步和生产力发展。新型预应力CFRP碳纤维板(CFRP)复合材料,可以使得抗震防灾及工程结构安全可靠度领域中大量房屋、桥梁、边坡、地下工程等重要工程结构的系统性安全产生科学有效的保障效应。

CFRP(carbon fiber composite)material is lightweight,high strength,tensile strength can reach 3000MPa and above,and has good environmental performance,and the construction operation is relatively simple,in recent years in the reinforcement of civil engineering beam,slab,column structure It has been widely used.Ordinary paste CFRP sheet can not exert the tensile strength of the material,which is not only due to the crack limitation of the concrete beam,but also limited by the deflection,but also by the peeling damage caused by the high bonding shear stress on both sides of the crack and the CFRP sheet at both ends limits.Since the unloading process is not performed or it is difficult to uninstall during the pasting operation,the CFRP cloth pasted under normal use does not participate in the force,so it has little effect on improving the structural performance.Normally attached CFRP fabrics will only participate in the stress under overload conditions,but due to strain hysteresis and the elastic modulus is equal to or lower than that of steel bars,the stress level of CFRP sheets under crack width limits is generally only The material strength standard value is about 1/20 or slightly higher.The high-efficiency post-tensioned CFRP board prestressed bridge structure reinforcement system proposed in this project uses CFRP board as the prestressed reinforcement material.Through pre-tensioning,the CFRP board is in a higher stress state(not less than 1000MPa)under normal use.In order to improve the normal use performance level of the bridge structure;through pre-tensioning,reduce the bonding shear stress under various load conditions,reduce the risk of peeling damage,and ensure that the CFRP board and the base concrete structure work together;under the limit of the bearing capacity,Can fully exert the tensile strength of the material and improve the utilization rate of the material;use the end anchor of the CFRP plate to completely solve the peeling and destruction phenomenon of the end of the CFRP material to ensure the reliability of the CFRP plate reinforcement;through the perfect anchor design and tensile process design In order to make CFRP plate prestressed reinforcement widely used in the field of research on the key structures of beams,slabs and columns such as houses and bridges,and promote technological progress and productivity development.The new prestressed CFRP carbon fiber board(CFRP)composite material can make the systematic safety of a large number of important engineering structures such as houses,bridges,slopes,and underground projects in the field of earthquake resistance and disaster prevention and engineering structure safety and reliability have a scientific and effective guarantee effect.