The Effects Which Semi-rigid Node Has On The Stability Of Portal Steel Tube Formwork Supports

In order to explore the mechanical performance of portal frame steel tube formwork supports, based on the full scale test of it and semi-rigid full scale node force performance experiment, the thesis analyzes the effects which semi-rigid node has on the stability of portal steel tube formwork supports. The main content is as follows:(1) The full scale test of semi-rigid node in which the mechanical performances of both semi-rigid nodes with a bolt on one end and ones with a bolt on both ends are studied under the pressure of varying eccentricities, with a contrastive study of steel tube with no bolts, gives the data of horizontal displacement, ultimate bearing capacity, instability mode, etc. of node center under the eccentric pressure.(2) In light of the experimental data from the full scale test of node, M-θ relation curve is obtained, and initial rotational stiffness of both semi-rigid nodes with a bolt on one end and ones with a bolt on both ends is explored.(3) The stability analysis of Model steel tube template stents is carried out, using steel frame stability analysis theory, considering the features of model steel tube formwork supports.(4) With the data of initial rotational stiffness from the full scale test of semi-rigid node, finite element analysis software ANSYS10.0is utilized to simulate semi-rigid node connection, the overall model of steel tube formwork supports is constructed, the effects that semi-rigid nodes have on the ultimate bearing capacity of portal model supports are analyzed, and a contrastive study of theoretical results and experimental ones is made.(5) The influencing factors on stable bearing capacity of portal steel tube formwork supports are:different node connection stiffness, different set-ups of level reinforcement bars and bridging, the disposition or absence of bottom horizontal tube and sealing tube.