Thermal-Mechanical Coupling Response of Modular Steel Structure under Fire

Modules of steel-structure modular buildings are usually connected semi-rigidly via welding or bolting, this connection method is between complete rigid connection and ideal hinge joint, therefore it's called semi-rigid connection.To accuracy simulate and analyze the fire resistance of steel structure under fire, it's necessary to study the connection node with self-locking and unlocking functions, model its bending moment-rotation angletemperature relations, and analyze the thermal coupling response.Existing studies haven't considered the difference between damaged and non-damaged nodes in terms of fire resistance duration and bearing capacity, or explored into the mechanical performance and deformation of connection node during the temperature drop stage in the later period of fire, and the analysis on the overall robustness of node during fire is not specific enough.To fill in these research blanks, this paper aims to give a thermal coupling response analysis on modular steel-structure under fire.At first, this paper performed finite element analysis on self-locking/unlocking connection node, analyzed the stress distribution, bearing capacity mechanism, and failure mode of the node under tensile force based on stress cloud map, figured out the effect of different parameters on the tensile-force bearing capacity and stress state of the node, and discussed the effect on the robustness of self-locking/unlocking connection node under fire.Then, this paper set a corner piece rotary connection node and a self-locking/unlocking connection node and performed static tensile simulation tests on them, then load-placement curves were attained and compared, and the bending momentrotation angle relation of self-locking/unlocking connection node under fire was derived.At last, experimental results of thermal coupling response of modular steel-structure under fire were given.