Application of high-strength strain-hardening cementitious composites (SHCC) in the design of novel inter-module joint

Abstract

The adoption of modular buildings has been promoted around the world in recent years, especially in densely populated areas such as Hong Kong that require a large number of new housing units to be quickly constructed. In modular construction, it is important to minimize the cast-in-place joints between prefabricated modules for a variety of reasons, including lowering the height of the building to reduce wind loads, as well as improving on-site construction efficiency. Combining the use of high-strength fiber-reinforced cementitious composites (HSFRCC) and steel plate confinement, the authors proposed a novel inter-module joint connection method and demonstrated that it can greatly enhance the bond strength and reduce joint size. In this study, the feasibility and effectiveness of using an alternative material – high-strength strain-hardening cementitious composites (SHCC) – is explored. Compared with HSFRCC, high-strength SHCC can attain similar compressive and tensile strengths while achieving considerably superior ductility. It also provides better capability in energy absorption and crack control. Tensile pull-out tests were performed to investigate the bond behavior between rebar and high-strength SHCC. It is reported that high-strength SHCC achieved enhanced bond performance compared to high-strength concrete, but the improvement was not as pronounced as HSFRCC. 3D models were built in a finite element program, and the simulations agreed well with test results. Parametric studies were conducted using the FE models to identify the main influencing factors of bond strength and to determine their relative importance. Design calculation methods were then developed to facilitate the engineering application of the novel joint connection.