Analysis and Design of Cable Roofs

Abstract

Applications of Cable structure in building have gained high popularity during twentieth century. Advancement in form finding and high speed computer applications, as well as rapid growth in construction technology has led its way to find economical and simpler design using cables for large span structures.

Present study is carried out with an objective to understand the various forms, geometry and structural behaviour of cable systems. Various types of cables, connections, anchorages, stabilizers and fittings for cable roof systems are studied.

Approximate methods used in the numerical analysis of single, double cable roof truss and saddle shaped cable net structures that provide preliminary design is described. These structures are usually very light and flexible and require an analysis method, which takes their non-linear behaviour into account. Exact methods of nonlinear analysis on which the software’s are based are presented.

Parametric study of change in cable forces for different sag/span ratios is presented. Study of effect of change in sag, span, pre-tension, method of analysis i.e. approximate, linear or nonlinear method, static and dynamic wind is discussed.

It is observed that iterative procedure is required to find optimum solution for minimum breaking strength, area and pre-tension value of cable force. In order to prevent slack of cables, pre-tensioning is essential in cable structures.

Design and detailing of saddle shaped cable net roof is carried out to understand and explain the various parameters that are critical in the design and selection of shape and material of cable roofs.