Dian-Bin Cao

A concrete-filled steel tube (CFST) column permits convenient and fast construction, and its use for high-rise buildings is increasing. Meanwhile, the CFST structure has great potential for use in residence buildings, owing to its smooth evaluation. A connection for a flat CFST column has also attracted increasing attention from scholars. An innovative connection between a flat CFST column and an H beam was proposed and cyclically tested in this paper. The flat CFST column, with a width that is equal to the thickness of the partition wall, was adopted to avoid the protrusion of the column into the corner of the room. The configuration of the innovative connection was introduced, and three full-scale specimens, considering different relative positions of the beam and column, were tested under cyclic load to failure. The seismic performance, including the failure mode, ductility, etc., were revealed and evaluated. It was indicated that the plastic hinge of the connection was prominently removed outward, due to the reinforced short beam and the interior-diaphragm, verifying the reliability of the innovative connection. Furthermore, an elaborated finite element model was developed, and the results of the finite element simulation were compared with the experimental simulations. This comparison confirmed the reasonability of the developed finite element model.

Modular steel construction (MSC) consists of the off-site prefabrication of a fully finished module and the on-site assembling of the module unit. The popularity of MSC is on the rise, attributable to its technical advantages of speed and quality of buildings with repetitive units. Inter-module connection is critical for the overall stability and load-bearing capacity of MSC. An innovative, fully prefabricated liftable connection (FPLC) using standard corner fittings and long stay bolts is proposed in this paper. This paper focuses on the axial compressive behavior and design of FPLC. Five full-scale specimens were tested under axial compression. Local buckling of the column and shear of the long stay bolts were observed during the test. It can be concluded from the test results that the load-bearing capacity may decrease as the number and diameter of the stay bolts increase. A three-dimensional nonlinear finite element model (FEM) was developed and validated against the test results by general purpose finite element software ABAQUS. Furthermore, a parametric study was conducted using the verified FEM to provide a better understanding of the axial compressive behavior of the FPLC. The results of the parametric study indicated that the corner fitting can be up to 15% lighter for columns with thicknesses of 6 mm and 8 mm without substantial reduction of the axial load-bearing capacity of the FPLC. Moreover, the location of the column can be adjusted to achieve a uniform Von Mises stress and equivalent plastic strain (PEEQ) distribution of the connection. The presented research work provides an engineering-practical inter-module connection on its axial compressive behavior, which will provide helpful references for further application of MSC.