Analysis of bolted ultra-high performance concrete joints

Ultra-high performance concrete (UHPC) is a composite material which has a remarkable self-compacting ability and highcompressive strength. Currently, UHPC precast construction is considered as an interesting option to take into account for civil engineering projects, in order to make use of its exceptional material properties. Discovering a practical and reliable method of connecting UHPC elements with fasteners has been recognized as a crucial factor in future construction projects. In this paper, the stress concentrations in an UHPC joint to predict brittle failure modes is investigated. Experimental results are compared with an analytical solution, which estimates the stress concentrations using the elastic properties of the anisotropic material and the geometry of the joint. The impact of the end and edge distances and elastic properties on the development of failure is presented for a bolted UHPC joint. The analytical solution proposed here that is based on closed-form equations, can be used to evaluate stress concentrations. Laboratory results on UHPC joints with bolts agree well with the model predictions. A theoretical analytical model for mechanically fastened precast concrete joints is, without a doubt, the reference for any experimental or numerical study of bolted UHPC joints.