Abstract:
In the recent Abstract: past, considerable number of tower failures happened in
telecommunication sector and power transmission sector in Sri Lanka. However, no lessons were
learnt and there is still a vacuum in strength assessment of towers. The objectives of this research are
conducting data survey on failed towers in Sri Lanka and identifying causes, analysing failed electric
transmission towers using finite element analysis and finding the causes for the failures and
developing simple methods to check tower capacity based on available simplified models. Four
telecommunication towers and a transmission tower were considered to identify the failure reasons.
Structural analysis of a transmission tower was done using a finite element analysis package,
SAP2000. A manual method to analyse 3D trusses was developed by combining unit load method and
tension coefficient method. To ensure the validity of proposed analysis methods, a simple tower
model was erected, structural analysis was done using both SAP 2000 package and manual method,
failure loads were predicted using SAP 2000 package, loading was conducted and results were
analysed. It is concluded that preliminary structural analysis with a specialised or a common
structural analysis package, has to be incorporated into prevailing steel tower design procedures.
Frequently admitted reason for telecommunication tower failures is tornados. However, nowadays
towers are being overloaded with antennas without proper consultation. Therefore it is essential to
carry out a detailed technical failure analysis to identify the reasons of failures. All these procedures
and results obtained are discussed in detail in this paper.
Citation:
Baskaran, K., Jeneevan, G., Jayasinghe, J.P.L.M. & Hettiarachchi, H.H.A.N.C. (2011). Strength assessment of steel towers. In N. Ratnayake (Ed.), Proceedings of the Civil Engineering Research for Industry Symposium 2011 (pp. 21-26). Department of Civil Engineering, University of Moratuwa.