• Mahmoud Alhalaby

Student thesis: Phd


Transmission towers are crucial assets for power systems worldwide. The most common transmission towers design is steel lattice towers. Other alternatives exist such as steel pole and Concrete Filled Double Skin Steel Tube (CFDSST) cantilever pole transmission towers. Given the serious technical challenges to conduct experiments, this project was conducted numerically using FEM in ABAQUS to investigate the static and dynamic behaviour of CFDSST transmission towers. In the current research study, three major parametric/case studies for the CFDSST transmission tower have been conducted. These are: static second-order effects, case studies for dynamic analysis and vibration serviceability, and the effect of foundation flexibility on the structural behaviour in particular due to the static second-order effects. The results and outcome of the parametric studies led to original contributions and findings. Three major and novel contributions to knowledge have been achieved after thorough analysis and processing of the parametric studies results. Firstly, a proposal of a simplified design method for estimating the second-order moments in CFDSST transmission towers which could be adopted in the design code. Secondly, the results of the full scale dynamic response of the CFDSST transmission tower confirmed the severe shortcomings of BS EN 50341 for the vibration serviceability and dynamic design. Thirdly, the foundation flexibility investigation was a fruitful investigation which proved that the rigid foundation assumption as advised by BS EN 50341 is not appropriate for CFDSST transmission towers. Simplified design methods have been proposed to circumvent the problem and accurately predict the additional magnification in second-order moments due to the foundation flexibility of the CFDSST transmission towers. The aforementioned novel contributions have the potential to influence the future publications of the electrical transmission towers design codes worldwide in particular BS EN 50341. Also, the methodology, contributions, and recommendations of the current research are highly relevant and unique to the following research areas and literatures: composite structures (CFST, CFDSST,etc..), electrical transmission towers, response and behavior of slender structures in particular the second-order effects and dynamic response. The current research study is a perfect example for the aforementioned research areas which often lack a practical objective and perspective in order to improve their usefulness and relevance to the industry and practicing professional engineers.
Date of Award31 Dec 2020
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorPeter Stansby (Supervisor), Sunday Oyadiji (Supervisor) & Lee Cunningham (Supervisor)

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