Prestressed Concrete Beam Type TL-2 Guardrail System at 31-inch Rail Height (600771)

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Problem Statement No. 2014-WV-67
Final Report:  Pre-stressed Concrete Beam Type TL-2 Guardrail System at 31-inch Rail Height

TTI Research Supervisor:
William F. Williams, P.E.
Associate Research Engineer
Texas A&M Transportation Institute
Texas A&M University System
3135 TAMU
College Station, Texas 77843-3135
(979) 862-2297
[email protected]
Pooled Fund Technical Representative:
Donna J. Hardy, P.E.
Mobility and Safety Engineer
West Virginia Department of Transportation
Traffic Engineering
Building 5, Room A-550
1900 Kanawha Bouldvard E.
Charleston, WV 25305-0430
(304) 558-9576
[email protected]

ABSTRACT

The West Virginia Department of Transportation (WVDOT) currently uses a side-mounted bridge rail system on pre-stressed concrete beam bridges that are designated for Test Level 2 impact conditions.  This bridge rail system uses a W6x25 post with a welded side bracket.  Each post with welded bracket is anchored to the side of the pre-cast/pre-stressed beam elements using four threaded inserts cast into the side of the beam element. The rail element for the system consists of a single HSS8x4x3/16 tube member with a 12 gage w-beam rail element attached to the front face of the tube. The current height of the rail system is approximately 28.375 inches in height.  The purpose of this project is to review the current geometry and design features of the bridge rail system with the height of the rail increased to the 31-inch height.  Details of the current system are shown in Figure 1.

Figure 1.  Current West Virginia Side Mount Bridge Rail Design (6-ft-3-inch Post Spacing).

Engineering strength analyses were performed on the post to determine if the new post size and anchoring details meet the strength requirements of MASH TL-2 impact conditions. The modified design is shown below in Figure 2. The design shown below meets the strength requirements of MASH TL-2. The post and steel block out have been modified such that these two components can be bolted together. Some adjustment (+4 inches) can be accommodated in this connection. Details of the proposed design developed for this study are shown in Figure 2.

Based on the analyses results, the details presented herein were recommended for implementation on bridges for MASH TL-2 applications

Figure 2.  Modified Pre-Stressed Concrete Beam TL-2 Guardrail
(6-ft-3-inch Post Spacing) at 31-1/8-inch Height.


2017-04-07