Study On Static Stability Of Single Layer Lattice Steel Cooling Tower With Semi-Rigid Joints

With the increasing scale of new cooling towers,the limitations of reinforced concrete cooling towers are becoming more and more prominent.Steel cooling towers are becoming the main direction of large cooling towers selection and research because of their outstanding advantages of high material recycling rate,high installation accuracy,short construction period and easy industrialization of buildings.As an important part of the steel cooling tower,the joint has a significant impact on the stability of the steel cooling tower.At present,there is no assembled joint used in steel cooling towers at home and abroad,and there is no research on the static stability of semi-rigid steel cooling towers.The single layer latticed shell steel cooling tower is simple in structure and easy to realize assembly production,so this dissertation mainly focuses on the research and development of semi-rigid joints for the single layer latticed shell steel cooling tower,the research of bending behavior of joints and static stability of structures.The main contents of this dissertation includes:?1?A series of new assembled joints?HCR,CHR,HCP?for single-layer latticed shell steel cooling towers were proposed.Static tests were carried out to study the anti-rotation performance of joints in the direction of strong axis under bending and shearing loads.The effects of connection mode,bolt row number and thickness of joints on moment-rotation curves and failure modes of joints were analyzed.The three types of joints?HCR,CHR,HCP?all have high initial stiffness K_ini and ultimate bearing capacity M_sup.?2?Based on ABAQUS finite element software,the joint finite element model is established considering the installation gap between plates,plates and bolts.By comparing the bending moment-rotation curve,failure mode and stress-bending moment curve obtained from numerical simulation and test,the numerical model can simulate the joint's mechanical performance well.On this basis,the static performance of the joints under bending-shearing,bending of fixed axis force and eccentric loads is analyzed.The moment-rotation curves,the initial stiffness K_ini,the ultimate bearing M_sup and the failure mode of the joints are obtained.?3?Based on ANSYS finite element analysis software,the stiffness of joints is substituted into the structure to simulate semi-rigid joints,and the cooling tower model of single-layer reticulated shell steel structure is established.Considering the joint mode and stiffness,height and mesh size of the cooling tower,the dual non-linear stability performance of the single-layer latticed shell steel cooling tower is analyzed by parameter analysis.The influence rules of each parameter on the structural stability performance are obtained,Three main instability modes of the single-layer latticed shell steel cooling tower are summarized.The stiffness distribution of joints in the structure is obtained.The stability analysis method of semi-rigid steel cooling tower considering the stiffness of eccentrically loaded joints is proposed,and the influence rules of the stiffness of eccentrically loaded joints on the stability performance of the structure is obtained.