Advanced Steel Construction

Vol. 17, No. 4, pp. 349-355 (2021)


 ENERGY DISSIPATING MODES AND DESIGN RECOMMENDATION OF

H-SHAPED STEEL BAFFLES SUBJECTED TO BOULDER IMPACT

 

Lei Zhao 1, Li-Jun Zhang 1, Zhi-Xiang Yu 1, *, Jian-Wei He 2 and Xin Qi

1 School of Civil Engineering, Southwest Jiaotong University, Chengdu, China

2 Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China

* (Corresponding author: E-mail:This email address is being protected from spambots. You need JavaScript enabled to view it.)

Received: 22 December 2020; Revised: 10 April 2021; Accepted: 15 May 2021

 

DOI:10.18057/IJASC.2021.17.4.3

 

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ABSTRACT

Flexible barriers are one of the most effective protective structures, which have been widely used for the mitigation of rockfalls. As the only compression members in a flexible barrier system, steel posts maintain the integrity of the interception structure to keep the function of the system. Due to the random trajectories of rockfalls, steel posts may be impacted by boulders directly. The impact scenario may result in the failure of the post and even the collapse of the system. In this paper, firstly, steel baffles were proposed to be an additional structural countermeasure to avoid the direct impact of posts. Secondly, numerical method was adopted to study the structural behaviour of steel baffles under direct boulder impact. Then, an available published experimental test of H-shaped steel beams under drop weight impact loading by others was back analyzed to calibrate the finite element model. Finally, numerical simulations were carried out to investigate the energy dissipating modes and energy dissipating efficiency of the H-shaped steel baffles. The simulation results show that there are three typical energy dissipating modes of H-shaped baffles subjected to boulder impact, namely flexural, local compression buckling and shear buckling. Local compression buckling is the most efficient energy dissipating mode. The thickness of the web of an H-shaped baffle is suggested to be 4 mm and 6 mm for the rated dissipating energy of 50 kJ and 100 kJ, respectively.

 

KEYWORDS

Steel baffle, Flexible barrier, Boulder impact, Energy dissipating mode, Design recommendation, Numerical simulation


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