The performance of bridges during large-magnitude earthquakes generated by the Cascadia Subduction Zone is an essential feature of the resilience of communities along the U.S. West Coast because bridges will be needed for pre-tsunami evacuation, emergency response, and economic recovery. This project developed a three-dimensional, nonlinear model of a typical bridge and subjected it to sets of simulated magnitude 9.0 earthquake ground motions to investigate the performance of bridges with a variety of structural characteristics.

Local, state, and federal engineers and emergency managers need reliable estimates of bridge performance after an earthquake so that they can plan pre-event mitigation, post-event response and mobility, and long-term recovery. This project provided improved predictions of the post-earthquake functionality of bridges in Western Washington following a Cascadia Subduction Zone magnitude-9.0 earthquake.

While expansion joints are a necessary component of bridges, they also contribute to noise pollution. This study investigated the design and feasibility of strategies to mitigate noise caused by modular expansion joints on Washington state’s Evergreen Point Floating Bridge (SR 520 bridge) over Lake Washington.

The Cascadia Subduction Zone is capable of producing large-magnitude, megathrust earthquakes that will affect the performance of every new and existing bridge in the western half of Washington state. This project evaluated the impacts on bridges of a magnitude 9 (M9) earthquake to help agencies prioritize earthquake retrofit efforts and to support the development of emergency response plans.

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.

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.

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.

In this study, recycled glass fiber reinforced polymer composites from end-of-life wind turbine blades were evaluated as a replacement for sand in cement mortar. In the last two decades, glass-based materials in the form of powder or fibers from recycled bottles and other products, and more recently recycled glass fiber reinforced polymer (GFRP) composites from end-of-life products or industrial waste, have been incorporated into cement-based mixtures in various proof-of-concept designs. To understand better how GFRP would affect the properties of mortar, researchers conducted a feasibility study to compare different GFRP sizes and percentages.

In past decades, many state departments of transportation and the Federal Highway Administration have begun working with ultra-high performance concrete (UHPC), an advanced cementitious material. WSDOT has not used UHPC in highway bridge applications, such as connection joints for precast concrete decks and girders, because of the concrete’s high cost and because of general lack of experience with it. The goal of this project was to develop a UHPC mixture using materials available locally and domestically as an alternative to commercially available, pre-packaged UHPC products.

For seismically active areas, designers must consider how bridge foundations will respond to ground liquefaction, particularly lateral spreading of the soil. Current design procedures generally rely on simplified analytical methods based on a two-dimensional description of the site geometry. However, numerous bridges affected by lateral spreading during past earthquakes have displayed three-dimensional soil deformation that cannot be captured in a two-dimensional analysis, and an analysis that assumes 2-D conditions may be overly conservative, leading to unnecessarily expensive design solutions. The objectives of this research were to identify and quantify the mechanisms that may result in potential reductions in the bridge foundation demands that develop during lateral spreading by considering the 3-D geometry of the bridge site.