Geodesic Dome Structural Analysis and Design

1 University of Southern Queensland Faculty of Health, Engineering and Sciences Geodesic Dome Structural Analysis and Design A dissertation submitted by Zhuohao Peng in fulfilment of the requirements of ENG4111 and 4112 Research Project towards the degree of Bachelor of Engineering (Honours) (Civil Engineering) Submitted October, 2016 i Abstract Geodesic dome is one of the simplest forms of structure which has a very unique spherical or partial-spherical shape. The skeleton of the structure consists a number of unequal and straight Structural members to form its many stable triangular elements in order to provide resistance to the gravitational, wind and seismic loads.

2 The Geodesic dome has the capacity to achieve large span without any form of internal posts, load bearing walls or deep beams or trusses, the load is evenly distributed through the surface of the dome. On the other side, a conventional building would require more material and space to achieve larger span, and deflection control and bracing requirement may become a challenge for the conventional form. Whereas, the Geodesic is very effective in limiting deflection, and it is self-braced through its stable triangulated elements.

3 Geodesic domes can be constructed from various materials, ( timber, steel) and a very light PVC cover is applied to the outside of the main structure to shield the dome from weathering. It provides a strength-to-weight ratio that many others could not compete. The fast speed of erection, competitiveness in material costs and its resilience to natural disasters have made dome construction applicable to many agricultural, commercial applications. The purpose of this report is to present the background information about Geodesic dome, also to verify a designing methodology and to develop Design procedure based on the most critical loading, that is wind load for this type of structure.

4 The aid of computational Analysis has been considered as the key tool to obtain Design data from the complex 3D dome model, and then manually checked against steel structure standards AS 4100-1998. In addition, an Excel spreadsheet was developed using finite element Analysis method to extract the forces for each element, then the results were compared against the outcomes from computational Analysis method for validation purpose. The spreadsheet was aimed to standardize the Design procedure and to reduce the time required for Analysis and Design in the future, and sensitivity Analysis could also be conducted easily and quickly using the spreadsheet.

5 Ii University of Southern Queensland Faculty of Health, Engineering and Sciences ENG4111/ENG4112 Research Project Limitations of Use The Council of the University of Southern Queensland, its Faculty of Health, Engineering & Sciences, and the staff of the University of Southern Queensland, do not accept any responsibility for the truth, accuracy or completeness of material contained within or associated with this dissertation. Persons using all or any part of this material do so at their own risk, and not at the risk of the Council of the University of Southern Queensland, its Faculty of Health, Engineering & Sciences or the staff of the University of Southern Queensland.

6 This dissertation reports an educational exercise and has no purpose or validity beyond this exercise. The sole purpose of the course pair entitled Research Project is to contribute to the overall education within the student s chosen degree program. This document, the associated hardware, software, drawings, and other material set out in the associated appendices should not be used for any other purpose: if they are so used, it is entirely at the risk of the user. iii Certification I certify that the ideas, designs and experimental work, results, analyses and conclusions set out in this dissertation are entirely my own effort, except where otherwise indicated and acknowledged.

7 I further certify that the work is original and has not been previously submitted for assessment in any other course or institution, except where specifically stated. Zhuohao Peng Student Number: 0061056711 iv Acknowledgements I would like to express my appreciations to everyone that has been involved in assisting me prepare and complete this project. The following people and organisations that I would like to make special mention of for without their support I would not have been able to complete this project.

8 Dr Sourish Banerjee for instructive supervision, guidance and suggestions, as well as his valuable time and effort. Bentley sponsorship of a free license of Microstran V9 over the period of the project. Strata Group Consulting Engineers for providing the idea of the project and supporting me completing the project. Family for selfless supports over the years in many ways to encourage and support me. ZHUOHAO PENG v Table of Contents Abstract .. i Certification .. iii Acknowledgements.

9 Iv Table of Contents .. v List of Figures .. viii List of Tables .. x Nomenclature .. xi Novel Aspect .. xiv 1. Introduction .. 1 Background Information .. 1 Project Aim and Objectives .. 2 Scope and Limitation .. 3 2. Literature Review .. 4 Introduction .. 4 Shell Dome .. 4 Geodesic dome .. 5 History .. 5 Geometry .. 6 Coordinate System .. 9 Strength and weakness .. 10 Structural Analysis of dome .. 10 Failure 11 Loading .. 12 Wind Load .. 12 Seismic load .. 13 Self weight and imposed loads.

10 14 vi Snow load .. 14 3. Model Generation and Loading .. 15 Geodesic Model Generation .. 15 Loading .. 16 Wind .. 16 Self-Weight and Imposed 21 Load Combination Cases .. 22 Assumptions .. 23 4 Excel Spreadsheet Development .. 24 Introduction .. 24 Flow Chart and Spreadsheet Structure .. 24 Data Input .. 25 Nodal Coordinates and Strut Information .. 25 Loading .. 25 Member Stiffness Matrices Construction .. 27 Global Stiffness Matrices Construction .. 31 Solution Procedure.