Institute of Fundamental Technological Research

The paper deals with a nonlinear analysis of a tall tower, with Circular Flange Bolted Connections (CFBC), in which friction and contact effects are taken into account. Due to these nonlinearities, a detailed dynamic model of the whole structure would lead to very complex computational problem, unable for practical solutions. To overcome these difficulties a reduced order model of CFBC is proposed. Such a model enables the simulation of the whole tower including nonlinearities in connections. The paper is illustrated with an example of model reduction and dynamic calculations for a contemporary telecommunication tower. The tower is assembled of 4 truss segments, of triangular cross section, interconnected with CFBCs. Finally, the influence of the number of modes, included in the reduced order model, on the accuracy and computational effect, is discussed.

Reduced order modeling, Circular flange-bolted connections, Dynamic substructuring, Nonlinear contact and friction effects, Telecommunication towers

A substructuring method for the prediction of the dynamic response of footbridges subjected to loadings induced by a pedestrian is presented. The dynamic system is composed of two independent subsystems. The first one is the model of the suspension footbridge, and the second one is the model of a pedestrian. The former is obtained using the standard finite element method, while the latter is created by applying a two-step identification approach. The first step is an inverse kinematics based on an experimental human motion analysis. The second one relies on Proper Orthogonal Decomposition extracting a number of most important modes, describing the motion of the pedestrian. The presented methodology will be demonstrated by a numerical example of the pedestrian-footbridge interaction.

dynamic substructuring, human-structure interaction, suspension footbridges