Research Into The Structure Selection And Stability Performance Of Large-span Specially Shaped Suspendome

With the development of architectural design aesthetic and functional requirements,specially shaped construction venues with ellipse or ellipse-like horizontal projection have increased gradually.Application of efficient suspendome in emerging large-span specially shaped roof can better meet the requirements of economy and security.The bearing capacity of suspendome is mainly determined by overall stability,so the study of structure selection and stability performance of large-span specially shaped suspendome is significant.On the basis of engineering application,selection of suspendome structure was summarized.Based on the finite element software Midas Gen,structure selection of large-span specially shaped suspendome was analyzed.The paper mainly studied the influence of grid form and form finding of elliptic suspendome’s reticulated shell on structural performance.Paper also studied structure selection of ellipse-like suspendome and equilateral polygon suspendome.At present,overall stability analysis method of suspendome basically used stability analysis theory of single layer reticulated shell,and there was no reasonable specification or standard for overall stability analysis method of suspendome.Based on the finite element software ABAQUS,whole process analysis was analyzed to study the stability performance considering geometric nonlinearity and material nonlinearity.By whole process analysis,this paper tried to put forward initial geometric imperfection method which is suitable for suspendome and get stability safety factor considering geometric nonlinearity simply to quantify the influence of material nonlinearity on the stability bearing capacity.By whole process analysis,this paper studied the influence of horizontal projection shape,rise-span ratio,height of poles and cable prestress on elasto-plastic stability performance.The results showed that structural performance of elliptic paraboloid suspendome is better than ellipsoid suspendome when rise-span ratio is low.Kiewitt-lamella suspendome has better structure performance.When construction models have no special requirements,the reticulated shell forms of ellipse-like suspendome and equilateral polygon suspendome should adopt cut surfaces of sphere,ellipsoid,elliptic paraboloid and so on.From the perspective of engineering design,the N-order eigenvalue imperfection mode method which takes first 20 order’s minimum value as the stability bearing capacity is reasonable.The result applying the consistent mode imperfection method may not be safe.Elasto-plastic stability bearing capacity of suspendome is greatly influenced by rise-span ratio and height of poles,less affected by the cable prestress level.When the large-span flat suspendome is controlled by stability bearing capacity,it is appropriate to optimize design according to the safety factor of elasto-plastic stability bearing capacity which is 2.0 rather than the safety factor of elastic stability bearing capacity which is 4.2;otherwise it will cause large economic waste.