A Developmental Study on the Anchor Bolts with Filling Cement Mortar Installed in Cracked Concrete

作为本研究的成果，阐明了后安装混凝土锚在填充水泥砂浆的混凝土凹陷孔中的以下性能。(1)我们可以通过在裂缝处切割的项目面积来估计安装在裂缝混凝土构件中的这种锚的抗拉强度，而不是在现有标准和指南中的破坏锥的整个项目面积。但当裂纹深度小于锚埋深的1/3时，裂纹可以忽略不计。(2)这种锚安装在混凝土有裂缝的构件中，灌注环氧树脂后，其抗拉强度恢复到安装在无裂缝的混凝土构件中的抗拉强度。(3)当锚安装在劣化的低强度混凝土构件中时，为了提高这种锚的抗拉强度，用与锚埋深相同直径内的低强度混凝土代替高强水泥砂浆或在锚栓附近的圆柱格罗夫内注入环氧树脂是最有效的。(4)通过对安装了这些锚杆的开裂梁与加高墙组成的梁-墙节点的抗剪试验结果表明，如果安装了锚杆的梁开裂，其抗剪强度与未开裂梁相比降低15%，但根据裂缝的数量，其抗剪强度没有差异。在裂缝中注入环氧树脂后，梁的抗剪强度略有提高。

The following properties of the post-installed concrete anchor in a dented bore of concrete with filling cement mortar were clarified as achievement of this study.(1) We can estimate the tensile strength of this anchor installed in a cracked concrete member by using the project area cut at cracks instead of the whole project area of the failure cone in the present standard and the guide. But cracks can be neglected in the case in which the depth of each crack is less than 1/3 of the embedded depth of the anchor.(2) The tensile strength of this anchor installed in the concrete member with cracks injected with epoxy resin recovers to the one instalied in the concrete member with no crack.(3) In order to increase the tensile strength of this anchor when we force the anchor to install in deteriorated and low strength concrete members, To substitute the low strength concrete within the diameter equal to the embedded depth and the same embedded depth of the anchor for the high strength cement mortar or to inject the epoxy resin into the cylindrical grove near the anchor bolt are most effective.(4) From results of the shear test of beam-wall joints which are made from a cracked beam installed with these anchors and a increased wall, If the beam installed with anchors are cracked, the shear strength decrease 15% compared with non cracked beams, but these is no difference in shear strength according to quantity of cracks. Also the shear strength increase slightly when epoxy resin injected into cracks of the beam.