Steel Structure Semi-rigid Connection Nodes Fire Resistance Performance Finite Element Analysis

Semi-rigid connection has significant advantages: a good seismic performance,convenient on-site installation and fast construction speed. The semi-rigid connectioncan accelerate the construction speed and shorten the construction period, reduce themanagement cost, so as to produce good economic benefit. Because many of theadvantages of the semi-rigid connection node is unmatched by other form ofconnection, the class node in the project application is bound to promote the steelstructure rapidly. However, the impact of fire on steel structures is fatal. Steel does notburn, but the steel mechanical property in high temperature is greatly affected bytemperature. Once the fire broke out, the steel easily damages. So fire resistance of thesteel structure of semi-steel connection node is extremely important.In this paper, connections of top-seat-angle with double web-angle are studied.Such nodes are generally considered as typical semi-rigid connection nodes. Using thefinite element ANSYS software, the three groups of finite element analysis model isestablished, two typical fire conditions to the nodes of the upper heat and the lowerheat as the fire conditions, the nodes are simulated by the hot-force coupling analysismethod. Through a large number of data identify and analysis, this paper concluded:(1)When the nodes temperature are more than600℃, Nodes upper warming affect thebearing capacity more than lower warming.(2) The angle steel is directly affected bythe fire in the state of upper part warming, lead its stiffness drop first, the angle steelcarrying capacity is also affected. Web angle steel in the middle of nodes, under thetwo conditions it is not directly affected by the fire, so the two conditions web anglecarrying capacity is not very different. At the same time the lower warming has a lesseffect on the bolt than the upper warming on it, compared with the upper warming, thelower warming is more beneficial for the bolt.(3) The upper angel steel yield first, thenotes continue deforming, the web angel steel yield too, eventually lead to the nodes failure. The nodes damage time is about10minutes or so, in such nodes design theupper angel steel should be well protected, try to avoid the angel steel by fire directly.(4) No matter in what condition under the role model, the nodes fire resistanceperformance can be significantly improved, and the internal stress redistribution ofnodes can also be improved, so that the nodes ministries by force are more reasonable.