Analysis Of Hub-Shape Inlay Joint And Its Influence On The Stability Of Single-Layer Lattice Domes

As lattice domes used more and more in constructions, the joints system have became various and many new forms have came out. The hub-shape inlay joints system is a kind of them which is suitable for single-layer lattice domes. It was developed by Chinese scholars and was widely used in large scale steel structures. The hub-shape inlay joint has capacity of bearing partial bend in the direction perpendicular to the dome surface but it can not transfer bending moment among members in the dome surface. Therefore, it is a typical kind of semi-rigid joint between rigid joint and hinge joint. The researches on loading capacities and its influence on the stability of domes are very important for structure safety, but these are rarely reported. So in this dissertation, following works have been done:1. Two kinds of hub-shape inlay joints were design according to related codes and corresponding finite element models were established with ABAQUS. The ultimate loading capacities and failure modes of the joints under different loading conditions were determined. It is verified that the capacities of hub-shape inlay joints can be replaced with that of the minimum section. So the calculating of capacities was simplified.2. To investigate influence exerted on the stability of domes by the stiffness of joints, a link element, Matrix27, in ANSYS was utilized as the element model to simulate the joints based on space beam element. Initial bending stiffness of the joints obtained from moment-rotation curve was brought into the models to make precise analysis of static behavior and stability of two single-layer lattice domes with hub-shape inlay joints. Geometric nonlinearity and initial imperfection of the structure were also considered in the analysis. Load-displacement curves and critical load of domes were obtained and were compared with those of domes with rigid joint and rigid-pin joint. The influence exerted on the stability of domes by the stiffness of joints was determined.In this dissertation, the simplified method of calculating hub-shape inlay joints'ultimate loading capacities was given, which provide a reference for joints designing. The influence on the stability of domes brought by the stiffness of hub-shape inlay joints was determined. This is very important in the designing of single-layer lattice domes and structure safety.