Numerical investigation on lateral movement and axial rotation of mullions in unitized curtain wall facades

Abstract

Most modern buildings are covered in lightweight, panelized, aluminum-framed façade structure composed of prefabricated panels, with the mullions serving as the main framing components. Transferring the lateral wind pressure on the skin materialto the primary structural frame is the mullion's primary purpose. Two of the three main causes of lateral movement in the main member are not taken into account by the current methods for analysing the stability of structural extrusions. They are the force produced by the pressurisation of the mullion's interior cavity and the moment transferred to the mullion from the wall's face material or mullion. This study analyses the various physical actions that cause a mullion's inner flanges to move horizontally or parallel to the wall, and the results have been compared to those generated using a finite element model. In the modelling approach Abaqus finite-element software is used to model the glass panel, aluminium glazing frame. It is found that the value of the lateral displacement obtained using numerical modelling for the male–female mullion combination is slightly lesser than the conventional method and new arithmetic expression by Adam et al.This study will show whether finite-element modelling is a viable approach for analytical evaluation of curtain walls. The simplification of the structural design process by Adam et al. will make it easier for the facade engineers to design the extrusions with maximum efficiency. The application of anti-buckling clip will help to reduce the lateral movement between the male and female mullions in unitized curtain wall. Since aluminium extrusion is a highly energy-intensive process, effective design of aluminium extrusions will reduce the amount of aluminium, resulting in significant cost savings. The reduction in mass of production will also substantially reduce greenhouse gas emissions.