Nonlinear Analysis and Design of Tensile Membrane Structures

Abstract

Membrane structures are one of spatial structures that allow for long span and light weight roofs. In many cases, the membrane roofs are supported with trusses or mats and prestressed together with cables to obtain a resistant shape for a given loading condition. For the design of membrane structures, nonlinear analysis is required. Besides, modeling of each membrane element and form-finding of the shape are of great importance in the design process. First, an equilibrium-finding analysis is conducted for the purpose of obtaining the optimal shape of the membrane structure, during which the initial stresses of the membrane and cables must be balanced. Next, the stress-deformation analysis is performed for the required loading condition. This analysis allows understanding the behavior of the structure and confirms that the design of the membrane satisfies the required safety factor for the construction.

In this research, a broad definition and explanation about spatial structures and in particular membranes are given. Then, the detailed procedure for the design and analysis of those is introduced with a complete explanation of the modeling and conditions to be considered. For a better understanding, two case studies are introduced and described where each step for the modeling, design and analysis is illustrated.

At the last part of this thesis, a parametric study on barrel vault shaped membranes is described. In this part, firstly regular membrane panels supported between arches are analyzed, leading to the development of a safe design aid for this type of membranes. Secondly, by adding one grade of irregularity, curved and inclined membrane barrel vault shaped panels are also studied, resulting on a similar safe design combination graph for each of this kind of panels. Finally, by the use of these design charts, simple design examples are illustrated to show the application of this study.