Static Stability Analysis Of Cross-ribbed Single-layer Steel Reticulated Shell

With the booming economy,the form of single-layer reticulated shells is becoming more diverse.Lvliang New City Sports Center Stadium,the upper roof has a length and width dimension of 204×160m,and the center point is 48m high.It adopts a middle large-opening single-layer reticulated shell with high-narrow H-shaped steel rib beam members and prefabricated concrete shell surfaces,and a steel arch with a large cross section is used as the edge member.It is a relatively novel single-layer reticulated form.The unique structural form poses a challenge to the design:the structural form of the reticulated shell makes it difficult to form a typical shell stress mode,and the concrete shell cannot provide in-plane stiffness during the construction phase,and the overall stability problem is prominent under the external load;The force-carrying mode of the shell also causes the rib beam member to be subjected to the bending moment,so that the beam height of the rib beam member is large,forming a cross-sectional form of the slender member,which is liable to be unstable when the static force acts,thereby leading to the overall shell shape.Instability,in order to ensure the overall stability of the reticulated shell and the stability of the rib beam members,the following work is done:Introduce the engineering background and general situation,expound the structure selection process and some design results of the Lvliang New City Sports Center Stadium,and introduce the static stability problem to be solved in the project.Using a combination of theory and finite element analysis,considering the distribution pattern of the initial defects of the reticulated shell by the consistent defect mode method.The arc-length method is applied to the nonlinear analysis of the whole process load-displacement curve of the large open-cell single-layer reticulated shell.The ultimate load factor is analyzed by analyzing the effects of material nonlinearity,initial geometric imperfections,bearing constraints and steel arch size on the stability of large open-cell single-layer reticulated shells.The analysis results show that under each parameter,the ultimate load factor of the reticulated shell of the project can meet the requirements of the regulations.Considering the initial defect distribution form by consistent defect mode method,the nonlinear stability analysis of single high-narrow H-shaped steel rib beam members by arc length method,and the bending moment-turn curve is obtained.Analyze the influence of web height-thickness ratio and flange width-thickness ratio on the stability and failure modes of rib beam members.Analyze the influence of stiffener arrangement on the stability and failure modes of rib beam members,and obtain the stress ratio at the limit of stability.Compared with the strength-to-stress ratio of the construction stage,the influence of the lateral support of the upper flange concrete shell on the stability and failure modes of the rib beam members is obtained,and the stress ratio at the time of stability limit is obtained,and the ratio of strength to stress in the normal use phase is compared-Through the above analysis results,a reasonable rib beam member section and stiffener arrangement are selected to ensure that the stability stress ratio of the rib beam member is higher than the strength-stress ratio to ensure the stability of the rib beam member.The stability of the high-narrow H-shaped steel rib beam member under the influence of the joint in the local substructure of the actual restraint of the reticulated shell is analyzed,and compared with the single rib beam member;without changing the geometrical dimensions of the joint,by increasing the wall thickness of the joints,the influence on the stability of the rib beam members is analyzed.The analysis results show that the increase of the wall thickness of the joint pipe can strengthen the restraining effect on the rib beam member,and thus the ultimate bearing capacity of the rib beam member.In this paper,the static stability analysis of large-opening single-layer reticulated shells and high-narrow H-shaped steel rib beam members can provide certain design guidance for the Lvliang New City Sports Center Stadium Project,and provide reference for similar structures and component forms in the future.