Advanced Steel Construction

Vol. 14, No. 2, pp. 115-141(2018)


A SIMPLE ANALYTICAL METHOD FOR EVALUATION OF FLEXIBLE ROCKFALL BARRIER

PART 1: WORKING MECHANISM AND ANALYTICAL SOLUTION

 

Z.X. Yu1,2, Y.K. Qiao1, L. Zhao1, H. Xu1*, S.C. Zhao1,2 and Y.P. Liu3

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

2National Engineering Laboratory for prevention and control of geological disasters in land transportation, Chengdu, China

3Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China

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

Received: 4 January 2017; Revised: 25 May 2017; Accepted: 5 June 2017

  

DOI:10.18057/IJASC.2018.14.2.1

 

ABSTRACT:

The flexible rockfall barrier system exhibits large deflection and complex contact behaviors such that sophisticated finite element method and full-scale test are widely used to design this kind of structures, which causes inconvenient for most engineers. In this paper, a simple analytical method is proposed for fast evaluation of the performance of the flexible rockfall barrier system on the basis of system deflection characteristics observed in the full-scale impact tests and, the component deflection characteristics from component tests such as the puncturing deflection of steel wire-ring net, elongation of energy dissipating device, sliding movement of supporting rope and rotation of support structure. The equation for prediction of large deflection of flexible rockfall barrier system was established. The overall deflection is contributed by its components and therefore the analytical solutions for calculation of component deflections were derived based on the space geometry analysis and verified by component tests. The analytical solution for steel wire-ring nets were validated by 17 puncturing tests and the maximum difference was less than 7.4%. Using the discrete ring net model, an explicit dynamic method was employed to simulate the nonlinear behaviors of flexible rockfall barriers with different design energies, i.e. 2000 kJ, 3500 kJ and 5000 kJ. The deflection of each component and the overall deflections from analytical solutions were compared with the numerical simulations with the maximum difference less than 7.9%. Thus, the proposed analysis solution for evaluation of large deflection of flexible rockfall barrier system is valid and ready for engineering design. A companion paper is presented in part two separately with full-scale test for further verification of the proposed method.

 

Keywords:

flexible rockfall barrier, impact, buffer performance, large deflection, analytical solution, full-scale test