Grant: Collaborative Research and Development Grants

The use of precast/prestressed structural concrete components offers several advantages over their cast-in-place counterparts including ease and speed of construction, achieving more efficient and complex shapes, long spans, high levels of fire resistance, enhanced durability and sustainability. However, it is essential that these individual structural components be assembled and connected to form an integral structure that can resist different types of load combinations during its service life. This research proposal focuses on the assembly and connection of two common types of precast structural elements. The first type is the assembly of adjacent bridge box girders that are butted against each other to form the bridge deck through transverse post-tensioning (TPT). The current practice is to apply the TPT through discrete transverse diaphragms, which does not prevent the cracking and differential deflection between girders, but rather interrupts utility lines and results in additional costs particularly in skewed bridges. The first objective of this research is to investigate the feasibility of providing uniformly distributed TPT through the top flange of box girders and evaluate cracking, deflection and load sharing capacity between girders. The second type of connection to be studied is the one between hollowcore slabs and supporting elements in buildings, which ensures the integrity of the structure. This connection is intended to resist horizontal in-plane loads. The current practice is to use reinforcing steel bars as anchors for such connections. However, no design guidelines are available to predict the capacity of such a connection or its mode of failure. The second objective of the proposed research is to evaluate, characterize and develop models to predict the strength of such connections. Full- and large-scale laboratory testing and analytical investigations will be performed to assess the performance of assembled precast elements to assess specific problems related to their application in bridges and buildings. This will lead to safe and new structures with improved performance, better durability, less construction cost and cutting the maintenance cost for infrastructure owners such as the Ministries of Transportation, Municipalities and Public Works.