Seismic assessment of guyed towers: A case study combining field measurements and pushover analysis

Telecommunication structures are essential components of communication and post-disaster networks that must remain operational after a designlevel of earthquake. This study provides dynamic field measurements of 138 m guyed tower located at Qussia city, Upper Egypt. In situ measurements of ambient tower vibrations are used to determine the dominant natural frequencies of the tower. The measurements were made using a LMS SCADAS system and four wireless vibration sensors for recording the ambient vibrations of the mast. The tension in the guy wires was measured by mechanical equipment. The dynamic properties of the guyed mast (natural frequencies and mode shapes) were extracted from these measurements. Results of the eigenvalue analysis of numerical models of the tower were compared with the natural frequencies and mode shapes extracted from the in situ measurements. The field measurements were used to update the finite element model. The nonlinear static analysis based on the updated finite element model was carried out. Seismic assessment and comparison between the original and updated models taking into account the deterioration in elements are presented.