DSHCC加固钢筋混凝土梁抗剪性能试验研究

Experimental study on shear performance of strengthened RC beams with DSHCC

采用致密化方法对普通"应变硬化水泥基复合材料(SHCC)"进行改进得到的"致密应变硬化水泥基复合材料(DSHCC)"具有更高的抗压、抗拉强度和弹性模量。已有研究证明DSHCC比SHCC具有更加优异的抗弯加固性能。基于RC梁抗剪原理,抗拉强度较高的DSHCC对加固梁抗剪性能也将非常有利。为此,对剪跨比分别为3.2和2.2两组共6根试验梁进行试验研究。对比分析加固梁和RC基准梁剪切破坏模式、承载力、变形能力以及裂缝分布等方面的不同;结合有限元和桁-拱理论分析,推导斜截面极限承载简化计算公式,并用试验结果验证该简化公式的可靠性。研究成果将为DSHCC材料及其在桥梁加固方面的工程应用和推广提供理论依据和参考。

Useing the Densified Particle Packing(DSP) method,Strain Hardening Cementious Composites(DSHCC) is improved into Densified Strain Hardening Cementious Composites(DSHCC) which has a higher compressive strength,tensile strength and modulus of elasticity. Bending experiment has proved that the RC beams strengthened with the DSHCC have more excellent flexural performance. Based on the shearing mechanism of the RC beam,the high tensile strength of DSHCC is also beneficial to the shear performance of the strengthening beam. So in this paper,six test beams in two groups which are respective with shear span ratios of 3.2 and 2.2 are studied; the differences of the shear failure mode,bearing capacity,deformation and fracture distribution between RC beam and DSHCC strengthened beam are analyzed; Based on finite element analysis and the Truss-Arch theory,a simplified ultimate shear strength formula of the DSHCC strengthened beam is derived and verified by the test results. This investigation proves that the DSHCC is also an excellent material for shear strengthening and the proposed simplified ultimate shear strength formula will give reference for the design of DSHCC strengthened beams.