Structural assessment of a guyed mast through measurement of natural frequencies

The structural investigation of 90 m. guyed communication tower was conducted using experimental and numerical analyses. Being unused for more than one decade, the structural evaluation was needed for recent loading configuration. As part of the investigation plan, a vibration based finite element model was built to predict the measured natural frequencies of the mast. The structural integrity of the tower was studied under expected dead and wind loading through non-linear analysis. The provisions of ANSI/TIA-222-G standards were employed to apply loadings and perform members’ checks. The field inspection and vibration measurements of the natural frequencies provided real properties of the full-scale mast. This improved the accuracy of the produced 3D finite element model of the existing guyed mast. The significant parameters in calibrating the model were the inertial properties of the mast members and the modulus of elasticity of pre-tensioned guy cables. Successful structural rehabilitation strategy was finally developed based on the analysis results. This paper presents an exceptional study for the experimental identification of the dynamic properties of a full-scale guyed mast in terms of its natural frequencies. The dynamic behavior of the guyed mast was conceived through the spectral analysis of the measured ambient response and the finite element model calibration. The final reliable finite element model enhanced an effective structural assessment.