Static Stability Of Single-layer Wooden Reticulated Shell With Varax Joints

Large-span space wooden reticulated shells have excellent architectural performance,outstanding structural performance and privides comfortable internal environment,which make it a very viable structural form.Due to the non-weldability and anisotropy of wood,the joints of wood structure are usually semi-rigid and it's failure behavior is complex.Furthermore,the structural performance of single-layer reticulated shells are affected by the stiffness of joints.Research on overall stability of single-layer reticulated shells is not comprehensive yet at home and abroad.It is necessary to carry out relevant research on the joint performance and overall stability of wood reticulated shells,which provides theoretical basis for analysis and design of relevant engineering projects.In this paper,research is carried out on typical steel splint bolted connection hub joints of reticulated wood shells,and the joint details are designed referring to the actual size of Varax joints of Guizhou Bijie dome.A refined solid element model is established with ABAQUS,and the load-deformation curve of the joint is obtained.Furthermore,an analytical model based on component method is established to calculate the key performance parameters including bending stiffness,bearing capacity and rotation capacity,so as the load-deformation curve can be established for design purpose of a joint.It is found that the analytical model performes reasonably well and provide a basis for engineering analysis and design of reticulated wood shells.Based on the grid layout of typical wooden reticulated shells,PYTHON modeling program is developed by to realize parametric modeling in ABAQUS of the whole reticulated shells.Based on eigenvalue buckling analysis and non-linear stability analysis,the load-displacement curves of reticulated shells with different forms are obtained.In addition,the effects of section size,rise-span ratio,span,flexural behavior of joints,initial geometric imperfections and load distribution on the static stability of reticulated shells are studied.Wood reticulated shells usually take wooden slabs as its roof layers,which is connected by dense nailing to the main components and purlins of reticulated shells.The wooden roof panel provides lateral restraints for each wooden member and effectively restrains the in-plane torsional instability of the reticulated shell.In this paper,the in-plane restraint effect is simulated by using a beam-roof composite element which was proposed by Tongtoe,the UEL subroutine of whom was revised and used in the current structural modelling.For roof structure without reliable in-plane restraint effect,the improvement measures to refine triangular mesh of secondary beam are discussed and its actual effect is analyzed.