Studies On Stability Of Vertical Glass Fins Under Bending In Full Glass Curtain Walls

Full glass curtain walls, also known as fin supported glass curtain walls, are more and more widely applied in lobbies of important public buildings. Glass fins are the main structure elements in full glass curtain wall systems, which could become unstable under in-plane bending moment. Existing researches on flexural-torsional buckling of glass fins are not adequate to propose design formulas for technical code JGJ-102. This thesis studied on the stability carrying capacity of single-piece glass fins that connected to glass panels by structural silicone sealant and put forward a suggested design formula of stability checking calculation.First, bearing capacity experiments of single-piece annealed glass fins (6mm & 10mm thick) under in-plane transverse loads were carried out. Two kinds of restraint conditions were considered. The one was to neglect the lateral restraint of the glass panels, including 11 test specimens. The other was to connect the glass panels under glass fins by sealant, including 10 test specimens. The development progress of flexural-torsional buckling in glass fins was obtained. The broken locations and failure modes were recorded. The buckling mode, displacement and stress results were given, from which the role in shear transfer and lateral restraint of silicone sealant connecting glass panels and fins were analyzed.On the bases of experiment results, a finite element model involving large displacement effect was created in ANSYS, through which buckling modes under different boundary conditions were ascertained by approach of eigenvalue analysis and the influences of section thickness and span-depth ratio on critical buckling loads were studied. The relationship among displacements, stressed and loads was found out by means of nonlinear analysis. With these correlation curves, influences of initial imperfection were discussed.Then, critical buckling moments of glass fins under different restraints and load patterns were derived with energy methods in elastic stability theories. In the guidance of the formulas, it was proved how various geometric dimensions and equivalent stiffness of sealant effected critical moments. And the results of different restraints and load patterns were compared.Estimation formulas of sealant's equivalent stiffness were established. According to that, silicone sealant in experiments could be converted to string stiffness parameters and the results of all above including experiments, finite element models and formulas could be compared, verifying the correctness by each other.Finally, a proper theoretical formula was chosen and simplified under practical dimensions to form a practical design method for stability of single-piece glass fins. The method was compared to the original formula, ANSYS numerical analysis and Australian code to prove its accuracy. Fins in a practical project containing full glass curtain walls were calculated using the method as an instance.