Effect of Pre-Cut Asphalt Fracture Planes on Highway Guardrail Performance

Effect of Pre-Cut Asphalt Fracture Planes on Highway Guardrail Performance

S.H. Lee E. Bakhtiary L.K. Stewart D. Scott D. White

School of Civil and Environmental Engineering, Georgia Institute of Technology, USA

| |
| | Citation



The preferred procedure for steel guardrails in the state of Georgia, USA for vehicle impact employs a post-installation machine to drive the posts through a layer of asphalt placed to retard vegetation growth around the system. However, in order to avoid undesirable restraint at the ground line, the AASHTO Roadside Design Guide recommends incorporating leave-outs. Using a leave-out in vegetation barriers is seen as less desirable because of issues including significantly higher expected costs, variability in the placement and spacing of posts, and the need for variable construction scheduling. In lieu of leaveouts, predetermined fracture planes, or “pre-cuts” were installed in the asphalt and evaluated in terms of ground restraint. An experimental program was carried out on an outdoor test site. Posts were installed in pre-cut asphalt and subjected to static loading to provide a better understanding of the behavior of a post restrained with an asphalt layer at the ground line. In parallel with the experimental program, a three dimensional finite element model was developed for a guardrail post installed through an asphalt layer. The model was refined using the experimental results from the test program as well as material testing. Results from the experimental program and finite element analyses indicate that certain pre- cutting configurations lead to significantly less ground restraint as desired.


asphalt, guardrail, pre-cuts, vehicle impact


[1] Georgia Department of Transportation, Standard Specifications: Section 641 - Guardrail.

[2] Georgia Department of Transportation, Construction Standards and Details: No.4381 and S-4.

[3] Scott, Static response of steel guardrail posts driven through asphalt vegetation barriers, 2015. Session 209, Transportation Research Board 94th Annual Meeting.

[4] Ray, M.H. & McGinnis, RG., Guardrail and median barrier crashworthiness. Technical Report No. project 20-5, NCHRP synthesis 244, 1997.

[5] Reid, J., Ls-dyna simulation influence on roadside hardware. Transportation Research Record: Journal of the Transportation Research Board, 1890, pp. 34–31, 2004. http://dx.doi.org/10.3141/1890-04

[6] Atahan, A., Vehicle crash test simulation of roadside hardware using LS-DYNA: a literature review. International Journal Heavy Vehicle Systems, 17, pp. 52–75, 2010. http://dx.doi.org/10.1504/IJHVS.2010.029623

[7] Atahan, Finite element simulation of a strong-post w-beam guardrail system, simulation. Transactions of the Society for Modeling and Simulation, 78(10), pp. 587–599, 2002. http://dx.doi.org/10.1177/0037549702078010001

[8] Borovinsek, M., Vesenjak, M., Ulbin, M. & Ren, Z., Simulation of crash tests for high containment levels of road safety barriers. Engineering Failure Analysis, 14(8), pp. 1711–1718, 2007. http://dx.doi.org/10.1016/j.engfailanal.2006.11.068

[9] Ren, Z. & Vesenjak, M., Computational and experimental crash analysis of the road safety barrier. Engineering Failure Analysis, 12(6), pp. 963–973, 2005. http://dx.doi.org/10.1016/j.engfailanal.2006.11.068

[10] Plaxico, C., Ray, M. & Hiranmayee, K., Impact performance of the g4(1w) and g4(2w) guardrail systems: comparison under nchrp report 350 test 3–11 conditions. Transportation Research Record, 1720, pp. 7–18, 2000. http://dx.doi.org/10.3141/1720-02

[11] LSTC, LS-DYNA keyword user’s manual-vol. 1-v971 build R8.0.0. LSTC, 2015.

[12] Plaxico, C., Patzner, G. & Ray, M., Finite element modeling and validation of a 3-strand cable guardrail systeminite element modeling of guardrail timber posts and the post-soil interaction. Transportation Research Record: Journal of the Transportation Research Board, 1647, pp. 139–146, 2007. http://dx.doi.org/10.3141/1647-17

[13] Wu, W. & Thomson, R., A study of the soil-structure interaction behavior of highway guardrail posts study of the interaction between a guardrail post and soil during quasi-static and dynamic loading. International Journal of Impact Engineering, 34, pp. 883–898, 2007. http://dx.doi.org/10.1016/j.ijimpeng.2006.04.004

[14] Tabiei, A. & Wu, J., Roadmap for crashworthiness finite element simulation of roadside safety structures. Finite Element Analysis and Design, 34, pp. 145–157, 2000. http://dx.doi.org/10.1016/S0168-874X(99)00035-9

[15] Bligh, R.P., Seckinger, N.R, Abu-Odeh, A.Y., Roschke, P.N., Menges, W.L. & Haug, R.R., Dynamic response of guardrail systems encased in pavement mow strips, fhwa/ tx-04/0-4162-2. Technical report, Texas Transportation Institute, 2004.

[16] Ross, H.E., Sicking, D.L., Zimmer, R.A. & Michie, J.D., Recommended procedures for the safety performance evaluation of highway features. Technical Report NCHRP Report 350, National Cooperative Highway Research Program, 1993.

[17] Sicking, D., Mak, K., Rohde, J. & Reid, J., Manual for Assessing Safety Hardware. AASHTO, 2009.

[18] Scott, D., White, D., Stewart, L., Bakhtiary, E. & Lee, S.H., Evaluating the performance of guardrail posts installed by driving through asphalt layers. Technical Report 13-21, Georgia Tech, 2015.

[19] Bligh, R., Seckinger, N., Abu-Odeh, A., Roschke, P., Menges, W. &Haug, R., Dynamic Response of Guardrail Systems Encased in Pavement Mow Strips. Technical report, Texas Transportation Institute, 2004.

[20] Coulomb, C., Essai sur une application des regles des maximis et min- imis a quelquels problemesde statique relatifs, a la architecture. Mem Acad Roy Div Sav, 7, pp. 343–387, 1776.

[21] Christensen, R. & Bonaquist, D.W., Evaluation of indirect tensile test (idt) procedures for low-temperature performance of hot mix asphalt. Technical report, NCHRP, 2004. http://dx.doi.org/10.17226/13775

[22] Pellinen, TK., Song, J. & Xiao, S., Characterization of hot mix asphalt with varying air voids content using triaxial shear strength test. 8th Conf. Asph. Pavements South Africa, 2004.