两种碳纤维板锚夹具的锚固性能对比研究
发布时间：2019-01-09 09:34
【摘要】：碳纤维增强塑料(Carbon Fiber Reinforced Plastics简称CFRP),具有轻质、高强、耐腐蚀等优点,在国内外工程结构加固中得到了越来越广泛的应用。碳纤维板和碳纤维布在结构加固中比较常用,用量远大于其它类型的纤维材料。与碳纤维布相比,碳纤维板材具有质量好、性能稳定、施工便捷等优点,碳纤维布在结构加固中总是需要进行浸渍树脂的施工环节,而现场浸渍树脂的方法存在质量不稳定,缺陷较多的问题,故在预应力CFRP加固技术中,预应力碳纤维板是主要的研究对象。在预应力碳纤维板加固技术中,锚夹具的可靠性是该技术性能优劣或成败的关键。可靠的端部锚固是预应力碳纤维板加固方法的前提条件,也是提高碳纤维板材强度利用率必须首先解决的问题。不可靠的锚夹具由于不能实现对碳纤维板的可靠夹持和锚固,预应力张拉水平就很低,且碳纤维板的使用应力水平也不易达到较高的水平,或者因为碳纤维板在锚夹具内发生滑移而使碳纤维板剥离或者产生较大的预应力损失。预应力碳纤维板加固技术发展到如今,其锚夹具的种类有多种,但在我国桥梁加固工程中常用主要是楔形夹片式锚具(以下简称夹片锚)、平板类型锚夹具(以下简称平板锚)、波形齿夹具锚(以下简称波形锚),其中夹片锚和波形锚的性能比较稳定,本文针对这两种锚夹具进行了对比试验研究,对两种锚夹具的各项力学性能指标进行测试和对比,找出两种锚夹具的的性能的异同,为工程应用及选择提供依据。在本文中,参照《预应力筋用锚具、夹具和连接器GB/T14370-2007》对传统预应力筋的锚夹具性能检测方法,专门设计了波形锚-碳纤维板组装件、夹片锚-碳纤维板组装件进行静力破断试验,针对两种不同形式锚具的各项实测数据进行性能对比,得到了如下主要成果:①夹片锚从设计原理上是一种“越拉越紧”的结构,为避免产生过大的挤压应力(碳纤维板的抗挤压能力较弱),那么夹片设计角度不宜大,且夹片与锚杯之间存在角度差,故在“夹片锚-碳纤维板组装件”的静力拉伸中,实测滑移量大大高于“波形锚-碳纤维板组装件”。而滑移量小,对控制预应力张拉精度和控制预应力损失较为有利。②基于文献资料设计的夹片锚对低强度碳纤维板能提供较好的锚固,但对较高强度的碳纤维板不能提供可靠的锚固。③在组装件破断试验中,两种锚夹具在碳纤维板的最终破坏形态方面差异较大,“波形锚-碳纤维板组装件”中的碳纤维板都能出现“发丝状”的破断形式,没有局部或整体的碳纤维板滑移,而“夹片锚-碳纤维板组装件”主要是滑移和局部断丝。
[Abstract]:Carbon fiber reinforced plastic (Carbon Fiber Reinforced Plastics), referred to as CFRP), has been more and more widely used in strengthening engineering structures at home and abroad because of its advantages of light weight, high strength and corrosion resistance. Carbon fiber sheet and carbon fiber cloth are commonly used in structural strengthening, and the amount of carbon fiber sheet is much larger than that of other kinds of fiber materials. Compared with carbon fiber sheet, carbon fiber sheet has the advantages of good quality, stable performance, convenient construction, etc. In structural strengthening, carbon fiber sheet always needs the construction link of impregnated resin, but the method of field impregnating resin is unstable in quality. There are many defects, so the prestressed carbon fiber slab is the main research object in the prestressed CFRP reinforcement technology. The reliability of anchor fixture is the key to the performance of prestressed carbon fiber slab. Reliable end Anchorage is a prerequisite for the reinforcement of prestressed carbon fiber sheet, and it is also a problem that must be solved in order to improve the strength utilization ratio of carbon fiber sheet. Because the unreliable anchor fixture can not realize the reliable clamping and anchoring to the carbon fiber sheet, the prestressing tension level is very low, and the use stress level of the carbon fiber plate is not easy to reach a higher level. Or because carbon fiber sheet slips in the anchor fixture, the carbon fiber sheet is peeled off or has a large loss of prestress. With the development of prestressed carbon fiber sheet reinforcement technology, there are many kinds of anchors and clamps, but the wedge-shaped clamped anchors (hereinafter referred to as clamped anchors) are commonly used in bridge strengthening projects in China. The performance of plate type anchor fixture (hereinafter referred to as flat anchor), waveform tooth clamp anchor (hereinafter referred to as waveform anchor) is relatively stable. The mechanical properties of the two anchors are tested and compared to find out the similarities and differences of the two anchors, and to provide the basis for engineering application and selection. In this paper, the corrugated anchorage-carbon fiber plate assembly is specially designed with reference to the test method for the performance of traditional prestressed tendons anchors, clamps and connectors, which are called "Anchorage for prestressed tendons, fixtures and connectors". The static breaking test of clamped anchor and carbon fiber sheet assembly is carried out. The performance comparison of the measured data of two different kinds of anchors is carried out. The main results are as follows: (1) the clamping anchor is a kind of structure which is "more and more tight" in design principle. In order to avoid the excessive extrusion stress (the anti-extrusion ability of the carbon fiber sheet is weak), the design angle of the clamp should not be large, and the angle between the clip and the anchor cup is different, so in the static tension of the "clip anchor-carbon fiber plate assembly", The measured slippage is much higher than the "corrugated Anchor-carbon Fiber Plate Assembly". The slippage is small, which is beneficial to control the precision of prestress tensioning and controlling the loss of prestress. (2) the sandwich anchors designed based on literature data can provide better anchoring for low strength carbon fiber sheets. But the high strength carbon fiber sheet can not provide reliable Anchorage. 3 in the breaking test of the assembly, the difference between the two kinds of anchoring fixture in the final failure form of the carbon fiber sheet is great. In "corrugated Anchor-carbon Fiber Plate Assembly", there is "hair-like" broken form of carbon fiber sheet, and there is no partial or integral slippage of carbon fiber plate, while "clip anchor-carbon fiber board assembly" mainly consists of slippage and partial broken wire.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.72
本文编号：2405450
[Abstract]:Carbon fiber reinforced plastic (Carbon Fiber Reinforced Plastics), referred to as CFRP), has been more and more widely used in strengthening engineering structures at home and abroad because of its advantages of light weight, high strength and corrosion resistance. Carbon fiber sheet and carbon fiber cloth are commonly used in structural strengthening, and the amount of carbon fiber sheet is much larger than that of other kinds of fiber materials. Compared with carbon fiber sheet, carbon fiber sheet has the advantages of good quality, stable performance, convenient construction, etc. In structural strengthening, carbon fiber sheet always needs the construction link of impregnated resin, but the method of field impregnating resin is unstable in quality. There are many defects, so the prestressed carbon fiber slab is the main research object in the prestressed CFRP reinforcement technology. The reliability of anchor fixture is the key to the performance of prestressed carbon fiber slab. Reliable end Anchorage is a prerequisite for the reinforcement of prestressed carbon fiber sheet, and it is also a problem that must be solved in order to improve the strength utilization ratio of carbon fiber sheet. Because the unreliable anchor fixture can not realize the reliable clamping and anchoring to the carbon fiber sheet, the prestressing tension level is very low, and the use stress level of the carbon fiber plate is not easy to reach a higher level. Or because carbon fiber sheet slips in the anchor fixture, the carbon fiber sheet is peeled off or has a large loss of prestress. With the development of prestressed carbon fiber sheet reinforcement technology, there are many kinds of anchors and clamps, but the wedge-shaped clamped anchors (hereinafter referred to as clamped anchors) are commonly used in bridge strengthening projects in China. The performance of plate type anchor fixture (hereinafter referred to as flat anchor), waveform tooth clamp anchor (hereinafter referred to as waveform anchor) is relatively stable. The mechanical properties of the two anchors are tested and compared to find out the similarities and differences of the two anchors, and to provide the basis for engineering application and selection. In this paper, the corrugated anchorage-carbon fiber plate assembly is specially designed with reference to the test method for the performance of traditional prestressed tendons anchors, clamps and connectors, which are called "Anchorage for prestressed tendons, fixtures and connectors". The static breaking test of clamped anchor and carbon fiber sheet assembly is carried out. The performance comparison of the measured data of two different kinds of anchors is carried out. The main results are as follows: (1) the clamping anchor is a kind of structure which is "more and more tight" in design principle. In order to avoid the excessive extrusion stress (the anti-extrusion ability of the carbon fiber sheet is weak), the design angle of the clamp should not be large, and the angle between the clip and the anchor cup is different, so in the static tension of the "clip anchor-carbon fiber plate assembly", The measured slippage is much higher than the "corrugated Anchor-carbon Fiber Plate Assembly". The slippage is small, which is beneficial to control the precision of prestress tensioning and controlling the loss of prestress. (2) the sandwich anchors designed based on literature data can provide better anchoring for low strength carbon fiber sheets. But the high strength carbon fiber sheet can not provide reliable Anchorage. 3 in the breaking test of the assembly, the difference between the two kinds of anchoring fixture in the final failure form of the carbon fiber sheet is great. In "corrugated Anchor-carbon Fiber Plate Assembly", there is "hair-like" broken form of carbon fiber sheet, and there is no partial or integral slippage of carbon fiber plate, while "clip anchor-carbon fiber board assembly" mainly consists of slippage and partial broken wire.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.72
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，本文编号：2405450
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