Experimental and numerical investigation on precast CECFST column-to-column connections subjected to axial and eccentric compression

Concrete-encased concrete-filled steel tube (CECFST) is a new type of composite member featuring superior structural performance and high construction productivity. This form of structural members has been increas-ingly used as columns in high-rise buildings and as piers in long-span bridges. Recently, to promote the appli-cation of CECFST columns in countries short of labour, e.g., Singapore, North America and Europe, an advanced precast CECFST column-to-column connection with rapid construction and excellent tensile performance was developed by the authors. However, behaviour of the developed precast connection subjected to axial and eccentric compression has not been studied so far. In this paper, an experimental programme including five connection tests was conducted to investigate compression performance of the developed precast connection. The test results showed that compression resistance of the precast connection could achieve that of CECFST columns, indicating that it is feasible to connect CECFST columns by the newly proposed precast connection to enhance construction productivity. Furthermore, an extensive finite element (FE) modelling programme was carried out to generate more numerical data by conducting parametric studies. The experimental and numerical results showed that connection configuration plays a pivotal role in load-carrying capacity of the precast connection. Based on EN 1994-1-1, one simplified strength prediction model was proposed for the proposed precast CECFST column-to-column connection. Compared with experimental and numerical results, the pre-dicted strength was conservative and consistent, indicating that the proposed approach can be used in the design of the precast connection.