Research News

Investigation of Ultra-High Performance Concrete for Longitudinal Joints in Deck Bulb Tee Bridge Girders

Many state departments of transportation have used ultra-high performance concrete (UHPC) in bridge construction because of its advanced mechanical properties. In this study, researchers tested a new UHPC mix, developed at Washington State University, for its structural performance when used in a reinforced spliced connection between adjacent concrete deck bulb tee (DBT) bridge decks. Because DBT bridges can be constructed quickly, WSDOT is interested in using them on major highways. Use of UHPC could make DBT bridges more suitable for the heavier traffic loads on such roadways.

Safe from Crime at Location-Specific Transit Facilities

Puget Sound transit agencies want to ensure the safety and security of transit riders. Transit operators have long monitored crime and are aware of high incident locations. However, they lack data-driven tools to readily match crime events with the locations of individual transit facilities and with transit service periods. This pilot project explored the use of data-driven tools to identify concentrations of criminal activity near transit facilities and illustrated how novel sets of disaggregated data on both crime and transit ridership can serve the development of models to assess the safety of transit riders at specific locations.

Benchmarking and Safety Assessment for Modified Lateral Spreading Design Procedure Using Three-Dimensional Nonlinear Finite Element Analysis

Liquefaction-induced lateral spreading is a critical design consideration for many bridges in highly seismic regions of the Pacific Northwest, with broad impacts on safety for the general public. The current design procedures used to estimate liquefaction-induced lateral spreading in bridge-foundation-soil systems are often overly conservative, with the result that the construction of bridges may be more costly than necessary. This project sought to verify the current modified simplified design procedure and to develop a database and benchmarking framework useful for future evaluations.

Improved Methodology for Benefit Estimation of Preservation Projects

This project evaluated WSDOT’s current process for calculating highway preservation project costs and benefits and then developed an improved approach. To quantify the regional economic benefits associated with its transportation investment projects, WSDOT uses software developed by the Federal Highway Administration known as the Highway Economic Requirements System—State Version (HERS-ST). The researchers developed a tool to supplement the HERS-ST for benefit and cost estimation processes. The improved method, combining the new HERS-ST-BAT tool with HERS-ST, will allow transportation agencies to more accurately and flexibly estimate changes in their own and user costs resulting from proposed pavement projects and to more effectively consider different investment alternatives.

Developing Extended Strands in Girder-Cap Beam Connections for Positive Moment Resistance

This project sought to increase the seismic safety of the state’s bridges by improving the connections among bridge components. A typical Washington state concrete bridge bent consists of cast-in-place piers, precast, pre-stressed girders, and a cap beam. Successful interaction among all three components must be achieved to transfer induced loads effectively and provide adequate resistance to seismic shaking. The cap beam comprises a precast crossbeam and a cast-in-place diaphragm, flush with the girders. To create the tension connection between the bottom girder flange and the cap beam, it is common to extend some of the bottom steel strands into the cast-in-place diaphragm, where they are anchored with strand vices and bearing plates. The goal of this project was to create a reliable, effective, and practically applicable way of anchoring strands extended from the girder into the cap beam.

A Data-Driven Safety and Operations Assessment of Various Left-Turn Phasing Strategies

Because drivers respond differently to different signal phasing sequences, engineers need to evaluate how drivers interpret the message that each phasing sequence is trying to convey. This research evaluated the safety and operational impacts of different left turn movement treatments at signalized intersections by using crash, video, and survey data. The results should help decision makers select more suitable signal phasing plans under various operational conditions.

Development of Surface-Mounted Smart Piezoelectric Modules for Bridge Damage Identification and Safety Monitoring

The goal of this study was to develop viable tools that utilize ultrasonic smart piezoelectric material (lead zirconate titanate, PZT) to assess the condition of concrete bridges. Existing non-destructive testing methods for inspecting concrete structures all suffer from limitations in accuracy, cost, maneuverability, in situ capability, and implementation. The researchers determined that the surface-mounted PZT system tested was effective in determining the wave modulus of elasticity of concrete structures and is a promising alternative nondestructive technique for assessing concrete properties.

Confounding Factors of Commercial Motor Vehicles in Safety Critical Events

When determining the causes of freight-related accidents, researchers need to disentangle the complex interactions among a range of causal and confounding factors, such as hours of service, time of day, traffic density, roadway type, environmental conditions, and driver behavior and characteristics. This study sought to uncover relationships between driver hours of service and a set of potential confounding factors related to time of day.

Safety Data Management and Analysis: Addressing the Continuing Education Needs for the Pacific Northwest (Phase 2)

Road safety is an evolving field, and preparing both students and practitioners with expertise in road safety is important. This project sought to respond to gaps in delivering transportation safety education and to develop introductory curriculum materials for both academicians and practitioners.

Evaluation of Motorcyclists’ and Bikers’ Safety on Wet Pavement Markings

Pavement markings such as single and double divider lines, edge lines, crosswalks, and bike lane markings are critical in guiding roadway users. However, pavement markings can also lead to catastrophic crashes for motorcyclists and bikers when they are wet or icy. This study evaluated three different pavement marking materials in dry, wet, and icy conditions, in the laboratory and in the field, to help improve rider safety.

Washington State Transportation Center