William F Williams

Design and Full-Scale Testing of Low-Cost Texas Department of Transportation Type T631 Bridge Rail for MASH Test Level 2 and 3 Applications

The purpose of this project was to design and test a low-cost bridge rail system that would be compatible with the Midwest Guardrail System (31 in. height) and minimized or eliminated deck damage when impacted by errant vehicles. The Texas Type T631 bridge rail developed for this project is a flexible, low-cost bridge rail system for Test Level 2 (TL-2) applications. The Texas Department of Transportation Type T631 bridge rail designed and developed for this project was evaluated under Manual for Assessing Safety Hardware (MASH) TL-2 in 2013. The bridge rail incorporated S3X5.7 steel sections designed to yield at the post baseplate. The post baseplate was designed to distribute the baseplate bearing and shear forces without causing damage to the 8-in.-thick reinforced concrete deck. The welds on the posts were designed such that the post yielded without tearing away from the top of the baseplate. The rail element consisted of a 12-gauge W-beam rail element. The rail element was attached to the post with a bolt of diameter 5/16 in. This bolt was designed to break away without adversely affecting vehicle performance. The posts were spaced 6 ft 3 in. on centers for TL-2. The post spacing was reduced to 3 ft 1½ in. on centers and evaluated for MASH Test Level 3 (TL-3) specifications in 2014. At the smaller post spacing, the T631 met all the performance requirements of MASH TL-3. Details of the design and testing of the T631 for MASH TL-2 and MASH TL-3 specifications are provided in this paper.

Retrofit Bridge Rail Design and Testing for a Historic Texas Steel Truss Bridge

The State Loop 481 steel truss bridge over the Llano River in Junction, Texas, is classified as a historic structure. The bridge is approximately 1,423 ft long and has a railing that attaches directly to the steel truss members and does not meet the current AASHTO Test Level 2 (TL-2) strength requirements. Many supporting truss members were not adequate to resist TL-2 crash force. The purpose of this research was to design a crashworthy retrofit bridge rail that met the current AASHTO TL-2 strength requirements without overstressing the supporting truss members. The new design maintains the historic appearance of the structure. This paper presents details of the new bridge rail design and an analytical procedure for determining the magnitude of force transmitted to the supporting truss members. Crushable-pipe blockouts located between the new retrofit rail design and the truss members were developed as part of this research and were used to minimize the crash force transmitted to the steel truss members. The new bridge rail design was successfully crash tested in accordance with the TL-2 requirements of NCHRP Report 350. A bridge rail expansion splice was developed for the new bridge rail design and was successfully crash tested in accordance with the Test Level 3 requirements of NCHRP Report 350. This paper presents the results of this research, details of the expansion splice, the new bridge rail design, the design procedure, and the results of the crash testing.

Design and Construction of Two New Retrofit Combination Steel and Concrete Bridge Rail Designs

The Florida Department of Transportation (DOT) has several bridges that were constructed in the early 1970s and use two parapet bridge railing systems that are combinations of metal and concrete. These railings use an aluminum post-and-rail system anchored to the top of a concrete parapet. Both systems are used on high-speed roadways. The rails are often damaged by vehicular crashes and nuisance hits. The damaged aluminum rail components are expensive to fabricate and replace. Rail 1 is 2 ft 9 in. high and uses a cast-aluminum post with a round-tube rail anchored to the top of a vertical concrete parapet. Rail 2 is 3 ft 3 in. high and uses a cast-aluminum post with a rectangular-tube rail anchored to the top of a concrete Jersey-shaped parapet. Both metal rails are anchored to the parapets by cast-in-place anchor bolts. This paper presents the designs and details of two retrofit steel railings that use adhesive anchoring systems. These new railing designs are less expensive and easier to repair than the aluminum post-and-rail system. The retrofit designs presented in this paper meet the strength requirements of Test Level 4 of NCHRP Report 350. Design information and full-scale strength testing data used to develop the Texas DOT T401 bridge rail were also used to design these two retrofit designs. These retrofit designs were successfully installed on six bridges in Florida (approximately 4,000 ft).

Structural Analyses, Design, and Testing of Retrofit Bridge Rail: Historic 794-ft Roy B. Inks Steel Truss Bridge in Llano, Texas

The Roy B. Inks steel truss bridge (listed in the National Register of Historic Places) over the Llano River in Llano, Texas, is approximately 794 ft in length with a posted speed limit of 40 mph. This bridge design is common to many of the historic bridges in the state. The bridge railing does not meet the current safety requirements of NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features (NCHRP Report 350) for Test Level 2 (TL-2). The railing used is attached directly to steel truss members. On the basis of structural analyses, many of these members are not adequate to resist TL-2 crash forces. The purpose of this research was to develop a retrofit bridge railing design that is crashworthy with respect to NCHRP Report 350 requirements and a design that can be used on similar historic steel bridges within Texas. Crushable pipe blockouts located between the new retrofit rail and the truss members were developed as part of this research and were used to minimize the crash forces transmitted to the steel truss members. The new rail design retains the historic appearance of the bridge. The retrofit rail design, along with a rail expansion joint developed for this project, was successfully crash tested with respect to NCHRP Report 350 TL-3 requirements. The results of this research, the new bridge rail design, and the crash test results for the new design are presented.

New Aesthetic Type T-1F Bridge Rail from the Texas Department of Transportation: Design and Test Level 3 Crash Testing

Aesthetic bridge railings that are Test Level 3 (TL-3) crashworthy have great appeal. As part of the project described here, the author worked closely with other designers from the Texas Department of Transportation to design, develop, and crash test an aesthetic and crashworthy bridge rail that meets NCHRP Report 350 TL-3 requirements. The aesthetic features of this bridge rail are easy to construct and repair. The bridge rail elements are mechanically attached to the posts and are not welded, to make the railing easier to construct and repair. The posts are fabricated from steel plate and are attractive and easy to construct. The rail elements, fabricated from high-strength aluminum, are attached to the steel posts after those are installed. The rail elements can be adjusted once in place and are also standardized highway barrier hardware. As a result of some simple and cost-effective curb reinforcement details developed as part of this project, damage to the concrete curb and deck was minimal from the crash testing. In addition, from previous testing, a TL-3 crashworthy transition had already been tested and approved for this new aesthetic bridge rail design. This bridge rail design is currently being implemented on new construction in Texas. This paper presents an overall review of the design of the aesthetic bridge rail, details of the design, aspects of construction, and results from the crash testing of the T-1F bridge rail.

Repair and retrofit anchorage designs for two Texas bridge rails

A project was focused on developing alternative rail anchorage systems for the Texas Department of Transportations T501 and T203 bridge rail systems. The project considered only epoxy adhesive anchoring systems for each of these railings for use in repair and retrofit situations. Full-scale testing was performed on both rail types, and strength data were obtained with instrumented strain gauges on the rail anchorage for both rail types. These data were analyzed and used to develop alternate rail anchorage systems for both T501 and T203 bridge rails. Long-term durability of epoxy anchoring systems was also considered. The retrofit-repair strengths from the dynamic and static testing for both the T501 and the T203 compared closely to the dynamic and static strengths of the current strengths capacities. In summary, the strengths of the retrofit designs were close to and in some tests exceeded the calculated capacities of the bridge rails. The static strengths were close to the dynamic 50-ms average strengths recorded from the bogie testing. The new retrofit-repair designs developed and tested for this project are recommended for implementation for use on any new or existing bridge projects. The use of the Hilti RE 500 adhesive anchoring system was successful in achieving the strengths needed to adequately anchor the retrofit-repair reinforcement for both the T501 and the T203 bridge rails. The information learned from this project can be used to retrofit and repair other bridge rail designs in the future.

Deception Pass Log Rail in Washington State

Washington State Route 20 (SR-20) in Northwest Washington passes through the Deception Pass State Park. The portion of SR-20 within the park was constructed by the Civilian Conservation Corps (CCC) in the mid-1930s. As part of this work, the CCC built a stone masonry bollard and log rail system to delineate the edge of the road and prevent early-model vehicles from leaving the roadway. Because of their age, quality of workmanship, and importance to the surroundings, the parks bridges and log rail are eligible for the National Register of Historic Places. Previous attempts to replace this rail with a crashworthy system were unsuccessful because of the concern that the aesthetic and historic integrity of the park be preserved. A new approach adopted by the Washington State Department of Transportation began with understanding the context of the highway and the concerns of the other stakeholders. In addition, the stakeholders were educated on the safety issues. As a result, a solution was developed and was acceptable to all. The primary solution involved the development of a new barrier that replicated the appearance of the original log rail. This barrier was crash tested in accordance with NCHRP Report 350 TL-2 criteria and is available for use at other locations at which an aesthetic barrier is desired.

Test Level 4 Bridge Rails

Design details and full-scale crash test results are presented for three bridge rails tested for compliance with NCHRP Report 350 Test Level 4 requirements. Designs of these rails are based on AASHTO LRFD Bridge Design Specifications. Each bridge rail consists of structural steel tubing rail elements mounted on wide-flange posts. The rails are generally stronger than many designs commonly used in the recent past. Full-scale crash test results demonstrated that all bridge rails meet NCHRP Report 350 safety performance requirements.