Analysis Of Tension Structure

Abstract

Cable supported structures have inspired and fascinated people for many decades. During the past two decades a number of large roofs have been built in the forms of cable-supported in which the main load-carrying elements are steel cables. These are subjected to tensile forces only, thus there are no stability problems and it is therefore natural to use high tensile steel rods or high tensile steel cables. Today, cable structures are recognized as unique and innovative structural solutions that create new and dramatic forms, while efficiently enclosing large volume spaces and providing new opportunities for transparency and natural light. While cable-supported structures are not new, the three-dimensional configuration of this structural system with multiple levels of forestay cables that splay and support loads in three opposing directions makes this structure the first of its kind. The structural system for this problem is a masted cable-stayed roof system of masts that are sloped and stabilized by 15 cables (nine fore-stay cables and six back-stay cables) on both sides which in turn support both side inclined roof girders. The behaviour of the Cable-supported roof is highly non-linear due to the presence of pretensioned cables. The non-linearity is due to the geometry and material. The large displacements due to the heavy loads are responsible for the geometric non-linearity and the stress-strain behaviour of the prestensioned cables is responsible for the material nonlinearity. In this work only the geometric non-linearity is considered. STAAD.Pro, a stiffness based software has been used to do the linear static and geometric non-linear static analysis. The results of linear and non-linear static analysis, displacements from STAAD.Pro, forces in masts girders and cables are compared. The design guidelines are given for the whole sequence of works and finally concluding remarks are made at the end of the work. Chapter 1 includes the introductory part of thesis, the classification of tension structures with different forms, phase of beahviour during their deployment, prestressing and service phase and objective of study. iv Chapter 2 describes the literature review based on cable-supported roof in which linear and nonlinear analysis published by different authors. Chapter 3 includes geometric configurations of cable mast, girders and anchorages. It also includes types of cable and their structural properties. Also includes fundamental criteria for the structure design. Chapter 4 includes core theory of non-linear analysis. It also includes different types of non-linear solution procedures like incremental method, Newton Raphson method or Modified Newton Raphson method and mixed methods. Chapter 5 includes 3-D modeling tips for cable-supported roof in STAAD.Pro 2003. It also includes how to done modeling of cable in STAAD.Pro. It also includes how to perform cable analysis static linear as well as static non-linear. Chapter 6 includes different types of load and load combination for the analysis of cable-supported roof. It includes dead load, live load wind load with gust factor and dynamic analysis of earthquake forces. Chapter 7 includes the results obtained from STAAD.Pro of static linear analysis. Also includes mode shape of the frame. Chapter 8 includes the results obtained from STAAD.Pro of static non-linear analysis. And compare force and deflection of static linear and static nonlinear results. Chapter 9 includes basic design of cable, main girder and mast of the cable supported roof. Chapter 10 includes the summary, conclusion and further scope of work.