Title: Design and simulation of two wooden-post W-beam guardrails to eliminate wheel snagging

Authors: A.O. Atahan, O.F. Cansiz

Addresses: Civil Engineering Department, Mustafa Kemal University, Serinyol, 31040, Hatay, Turkey. ' Civil Engineering Department, Mustafa Kemal University, Serinyol, 31040, Hatay, Turkey

Abstract: Recent crash tests on strong-post round- and rectangular-wood W-beam guardrail systems demonstrate that wheel snagging can be a serious concern for vehicle stability and impact severity. There are several methods that exist to minimise wheel snagging in strong-post guardrail systems. This paper aims to investigate the effect of one of those methods: the increased offset distance between post and W-beam rail. Extensive simulation studies are performed to determine optimum offset distances between the post and W-beam in both systems. Different designs with varying offset block depths are evaluated and their impact performances are compared. LS-DYNA, a versatile, nonlinear, large deformation, finite-element program is utilised to analyse different alternatives. Guardrail models previously validated against full-scale crash tests were used in the analysis. Simulation findings suggest that tendency to wheel snagging reduces with increased offset depths. 260-mm depth was determined to be the optimum offset distance between the wooden posts and W-beam. Simulation results show that when a nominal 260-mm offset distance is provided, wheel snagging and associated vehicle instability and impact severity can be alleviated in wooden-post guardrail systems.

Keywords: computer simulation; full-scale crash test; offset block; optimum offset; strong-post W-beam guardrail; wheel snagging; wood post.

DOI: 10.1504/IJHVS.2004.004031

International Journal of Heavy Vehicle Systems, 2004 Vol.11 No.1, pp.47 - 66

Available online: 27 Mar 2004 *

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