Nonlinear dynamic analysis based on experimental data of RC telecommunication towers subjected to wind loading

Marcelo A Silva,Reyolando M L R F Brasil

doi:10.1155/mpe/2006/46815

Marcelo A Silva, Reyolando M L R F Brasil

Open Access

https://doi.org/10.1155/mpe/2006/46815

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Abstract

The goal of this paper is to propose a nonlinear dynamic model based on experimental data and NBR-6123-87 to accomplish a nonlinear dynamic analysis of slender structures subjected to wind loading. At first we compute the static answer given by the mean wind speed. In this part of the problem we consider the concept of effective stiffness to represent the physical nonlinearity of material and aP-Delta method to represent the geometrical nonlinearity. Considering the final stiffness obtained in thatP-Delta method, we compute the dynamic answer given by the floating wind speed, according to the discrete dynamic model given by NBR-6123-87. A 40 m RC telecommunication tower was analyzed, and the results obtained were compared with those given by linear static and dynamic models.

Highlights

The models proposed by the Brazilian code NBR-6123-87 [2] to accomplish a dynamic analysis of structures-subjected wind loading are based on linear dynamic models
The Linear dynamic analysis (LDA) presented values of bending moment 1.3 times those given by the Linear static analysis (LSA), while the Nonlinear dynamic analysis (NDA) presented values 1.5 times those from LSA
In this work we propose a nonlinear dynamic model based on experimental data and the discrete dynamic model given by NBR-6123-87 [2]

Summary

Introduction

The models proposed by the Brazilian code NBR-6123-87 [2] to accomplish a dynamic analysis of structures-subjected wind loading are based on linear dynamic models. For the effects of the mean wind speed on structure, the authors consider a nonlinear behavior. The effective stiffness is given by Brasil and Silva [1] After this method of converging, we initiate the computation of the dynamic effects of wind given by the floating wind speed. The authors consider that the structure vibrates around an equilibrium position This position is that one given by the last iteration of the P-Delta method. The natural modes and frequencies of vibration are computed considering the effective stiffness given by the last iteration of P-Delta method. The sum of the static, given by P-Delta method with Brasil and Silva [1] curves, and dynamic components, provided by the discrete dynamic model of NBR-6123-87 [2], gives the structure behavior

Nonlinear dynamic analysis

Structure analyzed and numerical results

Conclusions