Experimental and numerical study on shear behavior of a demountable CLT-concrete composite shear connection

Recently, there has been a growing interest in using Cross-Laminated Timber (CLT) in the construction industry, particularly as slabs and walls. This heightened interest is attributed to CLT's favorable mechanical properties, ease of prefabrication, and environmental advantages. Consequently, CLT-Concrete Composite (CCC) floor systems have gained more attention for their application in mid- and high-rise buildings. These CCC systems offer substantial advantages over standalone CLT slabs, including enhanced bending stiffness, increased load-bearing capacity, and improved dynamic performance. However, a notable research gap exists when it comes to the deconstruction of CCC slabs, a crucial aspect for enhancing sustainability and reducing the environmental impacts of these structural elements. This study investigates innovative demountable shear connections designed for a reusable prefabricated CCC floor system. A series of push-out tests were conducted on six different shear connectors to obtain the shear properties of the connection. The demountable shear connections exhibited a load-bearing capacity similar to conventional permanent connections. Moreover, these connections demonstrated a significantly higher stiffness than existing options. One specimen was examined in a reuse scenario test to evaluate its reusability, which revealed a notable increase in stiffness during its second use. A three-dimensional finite element model of the push-out test was validated and calibrated with the experimental results. This model was utilized to study the load-bearing behavior of the notched connections.