Large Span Building Structures

Abstract

When a person thinks of an outstanding architectural space, the most likely image that comes in mind is a large-span structure. The recent renaissance in large span structures which has been centered on the creation of “GETTING OUT OF BOX” trend has given me immense encouragement to carry out my dissertation work on the same. The dimension and geometry of the structure such as span, radius and thickness can be used to define a large span structure. My entire thesis work was taken up with a view of keeping abreast with the rapid development in the field of large span structures. Complete documentation is developed step by step, clearly bringing out various important preparatory works. Relevant specifications and design checks are presented as and when needed. After reviewing the literature, a case of an existing roofing system of Iscon Arcade at C. G. Road, Ahmedabad, Gujarat, India has been selected to have better insight of large span structural systems. The existing system which is developed recently has been checked as per IS code requirements and design for the same system is carried out to procure the best way of working out the most economical system. This structural configuration is analyzed in STAAD-PRO 2003 for five different alternative systems listed below for dead, live, wind and earthquake loads. From static and dynamic analysis results, structural members are designed manually according to IS codes and all necessary checks are applied as and when needed. Chapter 1: Familiarizes with the ESSENTIAL CONCEPT of the large span structures, purpose of thesis and scope of work in brief. Chapter 2: Covers LITERATURE REVIEW in the form of historical development of large span structures in pre-nineteenth, nineteenth and twentieth century as well as various discretionary structural systems for large span building structures. Chapter 3: First step taken is to analyze and design the existing structural system with the use of Hollow Section members. TATA SHS and RHS HOLLOW Sections are employed in this study. General design criteria are discussed along with modeling and analysis results. ii Chapter 4: Considers the same structural system, but for having better insight of parametric study of the structure, VARIATION of SPACING in mainframe is accepted and the rest processes are repeated. Chapter 5: Introduces the analysis and design of the existing structural system with the use of N-Type TRUSS GIRDER made up from TATA SHS/RHS for main beams while purlins are analyzed as TATA SHS/RHS simply supported beams. Specifications of the truss girder are given in conjunction with analysis and design results. Chapter 6: Integrates the analysis and design of existing structural system with use of CONVENTIONAL ISMB Sections. Chapter 7: Last case digs deeper into the analysis and design of existing structural system with the use of CASTELLATED GIRDERS made up from conventional ISMB sections and analysis and design results are given in succession. More application of castellated beam and the behavior of open web beams are very well discussed in detail. Main beam of castellated section Chapter 8: Core of my work yields the study to optimization of structural systems in the vision of different parameters like comparison of axial force, shear force, bending moment, maximum deflection, natural frequency, forcing frequency, time period, mass participation factors and total weight of structure. It concludes major peculiarities of various systems adopted and their RESULTS COMPARISON in depth in order to achieve best way of obtaining most economical structural system. Chapter 9: Converses FUTURE PROSPECTS. References are attached at the end of thesis.