Study On Tensile Properties Of Bonded-metal-anchor Group For Post-installed Fastenings In Concrete Structures

Post-installed Fastening is a means of anchorage on existing buildings, includingexpansion anchors, undercut anchors, bonded metal anchors and bonded rebars. For itsreasonable load delivery, fast construction and other advantages, bonded metal anchors arewidely used. Anchor group is the most common form in practice, with greater differencesin mechanical properties compared with single anchor. Therefore, it is of greatsignificance on the study of anchor group.With the opportunity of modification of the Technical specification for post-installedfastenings in concrete structures, two groups of single anchor, double anchors, fouranchors, six anchors were tested and numerical simulated, which were described in detailas follows.(1)Research status at home and abroad was summarized, and the main factorsinfluencing the post-installed fastening system were analyzed, including the strength,reinforcement, thickness and cracks of the base material, anchoring depth, edge distanceand spacing, stiffness of fixture and so on.(2) The calculation method of tensile bearing capacity in different failure modeswere summarized, which were compared with the specifications at home and abroad, andcompared Fischer with HILTI product standards.(3)Test system of bonded metal anchor group was designed and two group of singleanchor, double anchors, four anchors and six anchors were tested. The failure mode,tensile bearing capacity and displacement of anchors were obtained.(4)The test results were analyzed and found that with the increasing of thickness ofthe base material, stiffness of fixture, quality of anchors and edge distance, the tensilebearing capacity of single anchor on average and the displacement of anchors wereincreased as well, and characteristic of ductile damage was more visible. Furthermore, theuneven coefficient of anchor force and the improvement coefficient of anchor force causedby stiffness of fixture were obtained. (5)With the help of ANSYS software, anchor group was numerical simulated. Theresult of numerical simulation was anatomized well with the results of tests.