Study On The Response Of Point Supported Laminated Glass Under Blast Loading Based On Dynamic Coefficient And Equivalent Thickness

As a new building material, glass has attractive properties making it widely used in the modern architecture. While accidental explosion happens frequently in modern society, the antiexplosion design of glass curtain wall has gradually become an important part of the architectural design. For point-supported glass curtain wall, the glass curtain wall 102-2003 JGJ specification provides solution of static deflection and stress, but the calculation of dynamic deflection during blast still remains empty. Therefore, in this paper, we attempt to obtain the maximum dynamic deflection of the point-supported glass plate during blast impact by substituting the depth of PVB laminated glass with an equivalent thickness, and transforming the dynamic problem into the static one by considering a dynamic coefficient, and finally referring to the solution of static deflection according to the specification. For the dynamic coefficient of the point-supported single layer glass plate under blast loading, there is no study focus on the negative pressure part, while only qualitative analysis on the positive pressure part can be found, and specific calculation method remains empty heretofore. As to the study on the equivalent thickness of PVB laminated glass under blast loading, existing equivalent thickness formula has its limitation for neglecting the effect of PVB on the interlayer shear force transfer, the unequal thickness ratio of the upper and lower layers of glass, the change of PVB elastic modulus(influenced by temperature) and PVB thickness.Therefore, this paper studies the dynamic coefficient of single layer glass and the equivalent thickness of laminated glass based on the finite element calculation. The concrete research content is as follows:(1) Study the effect of geometry and load factors on the dynamic coefficient of the pointsupported single glass plate. In the aspect of impact load, some qualitative analysis on its influence on the dynamic coefficient and its influence range is conducted. The effect of the lasting time of positive pressure and the peak load on the dynamic coefficient is studied with specific calculation method. In the aspect of geometry, specific analysis on the effect of thickness, length width ratio, long length and the distance of the opening to the contrary on the dynamic coefficient is conducted. Finally, a dynamic coefficient empirical formula was obtained by curve fitting.(2) The effect of geometry and load factors on the equivalent thickness is studied. Through a lot of finite element calculations, it is found that boundary conditions of the upper and lower proportion of glass thickness as well as the area and the type of loading almost has no effect of the equivalent thickness coefficient, while on the contrary, the thickness ratio of the upper and lower glass has a great influence on it. Further, the original formula of equivalent thickness is modified, and the influence of the thickness of the glass, elastic modulus and thickness of PVB has been studied. Finally, an equivalent thickness coefficient empirical formula was obtained on the basis of the above research.With the combination of the method considering equivalent thickness, equivalent thickness coefficient and the dynamic coefficient mentioned above with the static calculation of point-supported glass curtain wall provided by the glass curtain wall 102-2003 JGJ specification, this paper can provide some reference for the calculation of the deflection of the point supported glass curtain wall under the explosion load.