Determination of the Length-of-Need for Guardrail without Anchorage (Task Order DZ)

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Problem Statement

The Roadside Safety Pooled Fund has prioritized their research needs for various barrier systems. In certain situations, it is required to leave a guardrail system installed without anchorage on one end. This is usually a temporary situation during a construction or repair phase, and it often occurs when constructing a guardrail installation off a bridge rail. The anchorage, however, is vital to the crashworthy performance of the system. Therefore, the Roadside Safety Pooled Fund has prioritized an effort to determine the required length-of-need for a guardrail system without anchorage on one end. This project has been split into two phases because of budgetary availability. Phase 1 covers the computer modeling and simulation effort, and Phase 2 involves the construction, installation, and full-scale crash testing. Following a failed crash test, the scope was expanded to include investigation of guardrail washers to minimize the required length-of-need for a guardrail system without anchorage.  

Objective

The primary objective of this study is to determine the required length-of-need for a guardrail system without anchorage at one end. This phase will construct and full-scale crash test the system developed in Phase 1. Following the initial crash test, the system will be improved and another crash test will be performed.  

Benefits

This project will benefit the members of the Roadside Safety Pooled Fund by providing the required length-of-need for a guardrail system without anchorage on one end. This will aid in determining construction and repair phases by providing safer stopping points to suspend work limits. 

Products

The TTI research team will provide a guardrail system without anchorage at one end, which has been full-scale crash tested according to MASH guidelines. TTI will prepare and submit a research report fully documenting all of the work completed within this phase. This report will be submitted to the technical representative of the Roadside Safety Pooled Fund for review and approval.  

Implementation

At the completion of this project, the Roadside Safety Pooled Fund will have the required length-of-need for a guardrail system without anchorage at one end. The Roadside Safety Pooled Fund will be able to specify the length-of-need and any additional hardware which is needed when leaving one end of the guardrail system without anchorage.  

Work Plan

The research team will first install the guardrail system without anchorage at one end, as developed in the Phase 1 effort. The research team will then full-scale crash test the system according to MASH guidelines. The current budget allows for two MASH 3-11 crash tests. The impact location and direction of these two tests was identified in the computer simulation effort during Phase 1. Following the initial crash test, the research team will improve the system by increasing the length-of-need and/or incorporating additional hardware to improve connectivity between the guardrail and the posts. 

REFERENCES

1. American Association of State Highway and Transportation Officials, Manual for Assessing Safety Hardware – Second Edition, AASHTO Subcommittee on Bridges and Structures, Washington, D.C., 2016.

2023-04-13