Aeroelastic Response of Suspended Pedestrian Bridges Made of Laminated Wood and Hemp

Fabio Rizzo

doi:10.3390/infrastructures5070060

Abstract

The work described in this paper investigated, by calculating critical flutter speed, the aeroelastic response of suspended pedestrian bridges made of a laminated wood structure and hemp cables and compared them to bridges with a steel structure and harmonic steel cables. Critical flutter speed was estimated using a numerical two degree of freedom (2-DOF) generalized deck model based on finite-element modal analysis. The critical flutter speeds of two sets of 25 different structural configurations, obtained by varying the deck chord and the permanent deck loads, made of steel and of laminated wood respectively, were estimated using experimental flutter derivatives obtained from 30 wind tunnel experiments. One of the most significant results was that pedestrian bridges made of laminated wood and hemp have a higher torsional frequency than those made of steel and that this affects critical flutter speed. A case study was performed and discussed by analyzing the structural and aeroelastic response of a 250 m pedestrian bridge with a 12 m deck chord and two approximately 32 m tall towers.

Highlights

Advances in materials science and building technology permit the evaluation of new ecological solutions to reduce the environmental impact of constructions
Pedestrian bridges made of laminated wood and hemp are lighter and stiffer than those made of steel
The aeroelastic response of pedestrian bridges made with steel and with laminated wood was compared by varying the deck chord and the deck loads

Summary

Introduction

Advances in materials science and building technology permit the evaluation of new ecological solutions to reduce the environmental impact of constructions. This is common practice, made mandatory by codes in the field of energy saving. Together with stone, dominated bridge construction materials for many years It was only in the latter half of the 19th century that timber and stone encountered competition in the form of steel, with concrete becoming increasingly common later on. These new materials allowed bridges to be made longer, stronger, and more durable

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