Retrofitting of telecommunication tower legs

Frequent technology upgrades in telecommunications have led to an increase in wind loading on the towers that hold this equipment. The legs of lattice towers are critical members to the structure’s integrity as they transfer large portions of compressive load through to the foundations. Through the increasing amount of compressive load, these members could eventually buckle due to insufficient strength, which could lead to the failure of the whole structure. This has raised the need to reinforce existing structures. Currently within industry, to retrofit new members onto the exiting legs is a common method to improve compressive strength. While this is widely used in practice there is currently little research that has been carried out to investigate the effectiveness of these retrofit methods. This research investigates the retrofit of a circular hollow section (CHS) that has been strengthened with two steel rods. This research aims to provide greater clarity on the effectiveness of the retrofit design through experimental and numerical analysis. The experiment will involve testing the design under a hydraulic jack to obtain the failure load. In the current paper, ABAQUS software has been used to undertake a preliminary numerical investigation to determine the critical elastic buckling load of the design. From the preliminary research conducted it has been found that the design can increase strength between 220%-230%, however the accuracy of this data still needs further investigation, due to the control models not aligning with predicted values. Through further investigation, a simplified design procedure can be formulated, and the true strength of the design can be determined. Overall, this research will improve the safety of this design, which will yield both economic and environmental benefits for the future of the industry.