01784493

Monograph

http://www.trb.org/Main/Blurbs/182548.aspx

The objective of this project was to develop proposed selection guidelines to assist bridge engineers and highway designers in selecting an appropriate test level (TL) for bridge railings based on specific site and traffic conditions. The focus of the study was on TL2 through TL5 railing. TL1 bridge railings involve very low volume and low speed applications which are not widely encountered and are generally not considered practical except in some special situations like park roads. At the other end of the spectrum, TL6 bridge railings are presumably intended for locations where the severity of a penetration or rollover would be exceptionally catastrophic. A TL6 bridge railing would be warranted to maintain public support for the highway project, even if the barrier is not necessarily cost effective. In addition, there is only one crash tested TL6 bridge railing available at this time. It requires specially designed deck details to support the impact loads and additional dead load of the barrier. The vast majority of bridge railings that will be practical for use are, therefore, in the TL2 through TL5 range. The basic approach used in this project was a risk-based approach where the frequency and severity of crashes with bridge railings are estimated and the risk of observing a serious or fatal injury crash calculated. The third version of the Roadside Safety Analysis Program (RSAP) was developed to perform cost-benefit analysis, but was expanded during this research effort to perform risk-analyses as well. This report documents the research conducted to populate the RSAP database, run the RSAP simulations, and present the resulting selection guidelines for the selection of MASH TL2 through TL5 bridge railings. The literature reviewed and a survey of practitioners are presented in the first several chapters. The data gathered and the analysis conducted are presented alongside a discussion of the decisions made throughout the research in subsequent chapters. Finally, the proposed selection process and selection tables to accompany the process are presented at the end of the document with accompanying discussion and alternative selection tables for use in the establishment of policy. The recommendations are presented in their entirety in Appendix B for a quick reference.

Submitted March 2015.

NCHRP Project 22-12(03)

English

214p

2021

NCHRP Web-Only Document

9780309268844

Final Report

Digital/other

Appendices; Figures; Photos; References; Tables

Bridge railings; Crash severity; Guidelines; Risk analysis; Testing

AASHTO Manual for Assessing Safety Hardware; Roadside Safety Analysis Program

Bridges and other structures; Design; Highways

TRIS, TRB, ATRI

Oct 5 2021 9:35AM