F-Shape Concrete Barrier with Slotted Drain Holes (405160-19)

F-Shape Concrete Barrier with Slotted Drain Holes (2009-LA/8) (405160-18)

To See Phase II

Problem Statement

The Louisiana Department of Transportation (LaDOT) currently uses a concrete cast-in-place concrete bridge rail on Louisiana bridges. The F-Shape bridge rail is 32 inches in height and 15 inches wide at the base. Presently, for bridges that use this concrete F-Shape bridge rail, drainage is provided only at the ends of the bridge since there no opening provided through the bridge rail. LaDOT has proposed the use of 6-inch high by 24-inch long open slots located 10 ft apart at the base of the rail to accommodate drainage through the railing. The purpose of this project will be review the current geometry and placement of the drainage slots to determine if the slots will impact the crash performance of the F-Shape concrete bridge rail.

Background

Adequate storm water drainage is necessary for safety on vehicular bridges. For bridges utilizing continuously cast-in-place concrete bridge rails with no openings, storm water drainage is provided typically on the ends if drainage scuppers are not provided. During heavy rainfall events, drainage water can accumulate on the bridge structure. Drainage through the bridge railing can provide better drainage of storm water, thus improving vehicular safety. The purpose of this project will be to evaluate the size and placement of drainage openings in the concrete F-Shape barrier used by LaDOT.

Objective

Evaluate the geometry and placement of the drainage slots on the LaDOT concrete F-Shape Barrier with respect to vehicle impact performance requirements for National Cooperative Highway Research Program (NCHRP) Report 350, Test Level 3 (TL-3) specifications.

Benefits

This project will provide LaDOT with a viable option to provide drainage through the cast-in-place concrete F-Shape bridge rail.

Products

TTI will provide drainage slot details for the LaDOT F-Shape bridge rail.
A copy of these details and a brief letter report explaining our evaluation of the details will be provided for each participating member state.

Implementation

As a result of this project, drainage slot details for the LaDOT F-Shape concrete bridge rail will be prepared for implementation on new F-Shape bridge rail construction for LaDOT.

Work Plan

Task — Evaluate F-Shape Barrier Drainage Slot Details

The researchers will review the proposed 6-inch x 24-inch drainage slot details and make any revision(s) as necessary to improve the crash performance of the F-Shape bridge rail with the drainage slots.
As part of this task, a brief letter report will be prepared and submitted summarizing our evaluation of the design along with any recommended details to improve the crash performance of the drainage slots on the F-Shape bridge rail.

Evaluation

F-Shape Concrete Barrier with Slotted Drain Holes

Executive Summary – 405160-19

FHWA approval letter F-shape with slotted drain B-218 March 2011