Structural behaviour of post-installed reinforcement in wall-slab moment connections

Post-installed reinforcements (PIR) technology has wide engineering applications from new works to alteration and addition works. Not only does it help to support newly cast additions such as in modular units, but also facilitates structural rehabilitation as functioning as remedy for defective or misplaced couplers. However, the use of PIR has not been fully addressed in major reinforced concrete design codes worldwide. Based on the design philosophy and associated failure modes, the design of cast-in reinforcement can be extended to the qualified PIR systems with reference to the latest editions of AC 308 and EOTA EAD 330499/330087, in the USA and Europe, respectively. Hence, a review of the international codes such as ACI 318 and EN 1992-1-1 is envisaged. Although the traditional bonded anchor (BA) theory for fastening may apply to PIR, this design is only valid for short anchorage length. For longer design lengths or other failure modes, the strut and tie model (STM) and the Rebar Anchorage (RA) theory become more suitable. Various research has been done on the column-foundation connections of sub-structures. However, moment connections of wall-slab, commonly found in super-structures, are being overlook. Hence, the main theme of this PhD research is to incorporate these three theories into EN 1992 Part 1 and 4 with modifications to suit for the design of moment connections in wall-slab structures. Checking both existing elements and newly cast additions is suggested in design process. A series of full-scale experimental study is conducted to explore the structural behaviour of applying PIR bars that connect the wall and slab. The proposed STM, RA, and BA design methods are validated based on the experimental results. Design engineers may choose a suitable method to control the failure modes and the ductility performance of the PIR moment connections.