We understand that openings in concrete barriers often occur and need to be patched or spanned with different materials that are readily available. Materials such as w-beam guardrail, thrie beam guardrail, and steel plates are often used to span localized gaps in concrete barrier. These materials that are often used, provide a temporary measure by maintenance when concrete barrier is damaged by collisions. It is desirable that these repairs have a low-cost to install and are simple and easy to construct in the field. The purpose of this project is to determine the maximum gap/span that can be made in a concrete barrier using standard/readily available hardware that still meets the requirements of MASH Test Level 3. This project will be investigated using engineering and LS-DYNA computer simulations only for this Phase 1.

Objective

The purpose of this project is to determine the maximum gap/span that can be made in a concrete barrier using standard/readily available hardware that still meets the requirements of MASH Test Level 3. This project will be investigated using engineering and LS-DYNA computer simulations only for this Phase 1.

Benefits

The retrofit design that can span an opening in a concrete barrier (maximum span limit) that meets the performance requirements of MASH Test Level 3.

Products

A retrofit design using a maximum span distance in an opening in a concrete barrier that meets the performance requirements of MASH Test Level 3.

Work Plan

The objective of this project is to determine the maximum gap in a concrete median barrier. For this project, the TTI research team proposes the following work plan to accomplish this objective:

 

Task 1: Literature Review

The research team will perform a brief literature review to see if any available research has been performed on similar repairs/retrofit design(s) for gaps in concrete barriers. This survey will include a search of available databases and will not include a comprehensive survey of state DOT’s. All information gathered from this literature review will be considered and used for this project.

 

Task 2: Engineering Design and Detailing

Engineer design and detailing on a retrofit bridge gap design will be performed for this task. Design details will be developed using the Ontario Tall Wall Median Barrier. Cross section details of the Ontario Tall Wall are shown in Figure 1 below.

At this time, details will be developed using a 12-gage thrie beam (single not nested) guardrail spanning across a gap in the F-Shape concrete barrier. A 6-inch anchored steel strap plate will be used across the gap at the base of the barrier. A photo of the designs that will be considered for this project are shown in Figure 2.

After review of all available data from Task 1 and the results of the engineering design(s) developed for this task, A recommended design for LS-DYNA simulations will be recommended for Task 3.

 

The bridge gap design developed in Task 2 will be simulated using LS-DYNA. Simulations will be performed using MASH 3-10 and 3-11 specifications. Simulations will be performed on a range of gap widths until a critical/maximum width is determine that exceeds the MASH TL-3 specification criteria for MASH Tests 3-10 and 3-11. Gap widths of 18, 24, 36, 48, 60, 72” etc. until the limits of MASH Tests 3-10 and 3-11 are exceeded will be investigated. Based on these simulations, a maximum gap width using the design developed for this project will be recommended for full-scale crash testing in Phase 2 to be performed under a different project.

 

A brief technical memo will be generated and submitted for this task. This brief technical memo will summarize the recommend retrofit bridge gap design and the maximum recommended width based on the simulation results from Task 3.

 

Time Schedule

Started: February 2024
Time frame: 12 months

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January 23, 2025