抄録
A simultaneous crack extension pull-out model for post-installed anchor is presented. The anchor is such that used in various strengthening techniques for reinforced concrete structures. The properties of the infill material used for post-installed anchor are characterized by a nonlinear interface between the surrounding concrete and the anchor. This is a new type of anchor-infill assembly in which the infill material is divided into two layers for the purpose of providing a larger failure path length resulting in increase of energy absorption and pull-out load capacity. The mechanical properties of the infill layer are different from the surrounding concrete. Therefore, the existing pull-out model of deformed bars cannot be applied directly in this case. The interfacial de-bonding is examined by the strength criterion expressed in terms of interfacial shear stress. Pre-existing cracks representing artificial notches are assumed at the top of infill layers for identifying crack location and stabilizing its propagation direction. All the possibilities associated with two-cracks in the close vicinity have been investigated in detail. The objective of the analysis is to predict a set of material properties which result in simultaneous crack extension at the two interfaces and also to identify a simultaneous crack extension length which results in increasing the pull-out load capacity, energy absorption and failure path length, achieved at lowest increase in pull-out deformation. Limiting the pull-out deformation is desirable from the point of view of limiting damage. From the analysis, using proposed material properties and dimension parameters, simultaneous crack extension length, Ld equal to 0.3 is identified as the ideal length which results in increasing the pull-out load capacity by 31%, increasing the failure path length by 30% and increase the energy absorption capacity by 47% achieved at an limited increase in pull-out displacements of 20%.
