Home Skip to main content

MPC
Research Projects (2004-05)

Identifying Number

MPC-234

Project Title

Impact Performance Testing of Roadway Safety and Security Barriers, Year 3

University

Colorado State University

Project Investigator

Dr. Richard Gutkowski
Colorado State University
(970)491-8291
gutkowsk@engr.colostate.edu

External Project Contact

N/A

Project Objective

The objective of the project is to develop and implement an impact test method to provide an affordable, logistically convenient preliminary performance test of roadway security barriers.

Project Abstract

A variety of portable safety and security barriers for directing traffic (public events, sports facilities, etc), and securing private and public locations against access (court houses, schools, etc.) have been developed. Some higher capacity systems have been developed for use on and around high speed automobile racing tracks. Generally, the barriers are hollow, plastic composite walls and use dead weight fill (sand, water) to resist impact without interconnection to the ground. Heavier solid systems, such as a concrete Jersey Wall type configuration, are used in highway construction as well. These are much more expensive and require heavy equipment to relocate them. Few of the filled, lightweight systems have been crash tested to meet federal standards, although some users have conducted their own impact tests. Typically, manufacturers are small businesses without the resources to conduct federal tests similar to crash tests of bridge guard rails. Thus, developing a comparable impact test method to conduct dependable preliminary tests has great merit.

Task Descriptions

Full-scale impact testing is the most effective method of realistically evaluating the safety performance of guard rails, median barriers, bridge railings, crash cushions, break away supports, work zone traffic control devices, and other hardware. NCHRP Reports 230 and 350 present specific impact conditions for vehicle mass, speed, approach angle, etc., for various vehicles. Impact speeds range from 20 to 60 mph and approach angles vary from 0 to 25 degrees. Dynamic tests include use of a gravitational pendulum, drop mass, or bogie vehicle. Procedures were devised to subject roadside safety features to serve vehicle impact conditions rather than to typical or average highway situations. Sometimes, static tests are used during the early stage of development when certain critical details and connections require strength/deflection evaluation.

CSU researchers have conducted preliminary performance static and dynamic pendulum tests of bridge guard rail systems. Indeed, one system subsequently survived a federal crash test done by other researchers. CSU also has the physical capability to include a bogie vehicle type of test at very high impact speed. Thus, these capabilities are being used to configure the needed impact test set-up and conduct physical tests of actual safety barriers.

A sequence of steps was planned over a two-year period. In Year 1 (Phase 1), CSU researchers configured a simplified, economic test configure which closely realized many of the recommendations of NCHRP 350. A surrogate test vehicle was used in an inclined flume on a steep incline and produce the Impact Severity test levels required by NCHRP 350 for Level 1-3 type vehicle approval. The performance of the surrogate vehicle and flume incline and track were acceptable. However, confinement limitations at the base of the flume constrained the physical set-up of the barriers themselves. Specifically, the angle of attack was nearly head on, not angular, and the vehicle could not approach on a horizontal plane. In addition, only 3 barriers or less could fit in the area at the base of the flume.

The objective of the Year 2 (Phase 2) continuation study was to improve the test by relocating outside the flume on a to be constructed inclined track, using real vehicles, and avoiding the physical constraints to allow setting up a much greater number of linked barriers, so true system performance is examined. An inclined hill side adjacent to the flume provides the embankment needed. A roadway at the base of the hill and adjacent open space allow for the placement of the multiple barriers needed. Beds of flat bed trucks are being used to build the ramp and a curve segment will be included to enable impact in horizontal plane, at the desired angle of attack. The hill side topography must be modified relative to original geometry and some intermediate soil braces added, due to soil and rock characteristics actually encountered. A short lifting ramp to more easily place the vehicle in position will be constructed as well. Performance testing will then be conducted on actual security barriers using trucks (without occupants) to be rolled in a guided manner down the ramp. The outcome of the use of test set-up will be assessed using the established criteria for safely and properly conducting the test. These criteria were established in Phase I.

  • Complete the topography of the site
  • Complete the additions to the ramp
  • Install a barrier system for testing
  • Conduct the impact test
  • Assess the performance of the ramp and test set up
  • Make necessary improvements
  • Compose an MPC report on the outcomes
  • Present findings to interested parties

Milestones, Dates

Starting Date: August 15, 2004
Ending Date: June 30, 2005

Yearly and Total Budget

$68,879

Student Involvement

One graduate student is the primary researcher on the project. Many graduate and undergraduate students assist in the construction activities of the construction team, and will be involved in conducting, observing, monitoring the test.

Relationship to Other Research Projects

An MPC project (MPC-235) on "Highly Flexible Crash Barriers" was conducted at CSU, independently by another researcher. It focused on basic research in regard to material response to high strain rates and numerical modeling of response of hypothetical system and possibly configuration of "soft" crash barriers for highways. That work is being continued by a larger grant from the National Science Foundation. Its outcome could lead to systems that could be tested in the impact test set-up devised in the work described herein on security barriers.

Technology Transfer Activities

Techniques for developmental performance testing will result. An MPC technical report will be developed and outcomes will be presented via the TEL8 teleconference system in the monthly MPC InfoX technology exchange series with regional transportation agencies. Publicity about all of the MPC projects is available through the MPC website maintained at NDSU. It is anticipated that industry will be involved in the performance test phase, to lend practicality to the tests and observe outcomes for use in practice.

Potential Benefits of the Project

Recently interest in portable barriers has heightened with concern about terrorists attacks creating nationwide security needs. Indeed, the Fort Collins Army Reserve began using one of the portable barrier systems as a safety shield for its facilities. That system has also been used by the City of Ft. Collins Justice Center, at the new Invesco Field in Denver, and the Platte River Power Authority's Rawhide Power Plant and its substations. A local manufacturer was also belatedly approached about potential use of portable barriers at the Salt Lake City Olympic Games site. Lack of credible performance data was a deterrent to immediate acceptance. Thus, a step toward more rigorously verifying impact performance at more affordable cost would help overcome that concern as well as encourage conduct of full federal crash tests, if needed.

TRB Keywords

Impact tests, performance tests, safety, security barriers

NDSU Dept 2880P.O. Box 6050Fargo, ND 58108-6050
(701)231-7767ndsu.ugpti@ndsu.edu