In-Plane Strength of a New Self-aligning Bolted Connection for Precast Concrete Wall Panels

The modular construction industry has seen significant growth in recent years owing largely to its faster construction, improved quality, and lower costs. The need for a design that can help manage tolerance errors has been identified. To address this, a new self-aligning bolted connection for use between precast wall panels in total precast construction projects was developed. The connection is made of a u-shaped insert which is bolted to a frame embedded within the wall panel. A z-plate connects adjacent u-shaped horizontally while a flat bar connects the u-shapes at vertical connections. The z-plate and long flat bar are then bolted in place. In-plane, tensile, system testing was conducted on the horizontal connections. Four 2 m × 2 m × 200 mm reinforced concrete wall panels were built with the connections in place. The u-shaped inserts were attached to the internal frame of the wall panels using varying anchorage methods. A total of 16 connections were tested, six of which used no additional anchorage when connecting to the frame. This was compared to four connections using three anchor bolts, and another four connections using five anchor bolts. Two of the connections were in double configuration where two u-shaped inserts were connected to the frame at a location, compared to the single connections that only used one. One of these used ten anchor bolts and the other used six that connected into a steel plate. The single connection with no anchorage failed either at the internal frame or the z-plate depending on the configuration of the internal frame at the location. The singles with three and five anchor bolts exhibited similar behaviour and failed at the z-plates and the doubles were found to have nearly double the capacity of the singles. The failure of the z-plates was shear tear-out failure of one of the main structural bolt holes.