In the last three decades, advanced technologies such as structural control and health monitoring techniques have developed to the point where they have been applied in a few full scale structures. The focus of this research program is the development of innovative and implementable means for mitigating the devastating consequences of severe natural and man-made hazards through structural control and health monitoring. Specifically, the structural control research focuses on the use of magnetorheological (MR) fluid dampers, because they are particularly suited to civil engineering applications. The current research program examines a number of important issues which need to be addressed before this technology is widely accepted and routinely implemented for seismic resistant structural design. Ultimately, the goal of this research is to develop guidelines which can be used by design engineers to employ these devices in new construction and retrofit applications. Furthermore, Structural Health Monitoring based on dynamic behavior has been a topic of interest for researchers who are looking for alternative solutions to the current techniques for structural inspection. We have developed a new technique based on changes in the dynamic characteristics of the structure and performed some successful numerical studies on a bridge model. Large structures such as cable-stayed bridges would likely be the first structures in implementing these techniques because of their importance and cost, although these methods could be applied to a wide variety of structures. The Washington University Structural Control and Earthquake Engineering Laboratory was developed to experimentally verify the systems with the greatest potential.

The effects of soil-structure and fluid structure interaction for lock structures and their critical components during seismic events is not well understood. Fluid-structure interaction is currently being ignored in the design of lock structures. These interactions can have catastrophic impacts on the continued-operation of such a structure after an earthquake. The loss of operation of a lock structure for even a short period of time can be an economic disaster. Each barge that cannot pass through the lock in a timely manner is estimated to cost the GNP approximately $40,000/hour. Critical components to be examined and assessed for seismic vulnerability are the lock walls, lock slab, miter gates, lift gates, and guide walls. Current design tools use very crude and simple models to account for seismic effects. Advanced tools including soil-structure interaction and fluid structure interaction need to be developed to have a true sense of the applied seismic loads and their effects. Use of the most recent experimentally measured behavior will be compared to current and proposed analytical solutions. Research results will be used to enhance current theory, modeling assumptions, and design procedures and to implement these enhancements within the current assessment tools used for the analysis and design of lock structures. This work is being conducted in conjunction with researchers at the U.S. Army Corp of Engineers and undergraduate researchers would attend periodic meetings at the USACE-WES facilities and tours of the regional lock and dam structures with the research team.

Prof. Tom Harmon - Clifford Murphy Professor & GAANN Advisor

There have been many significant improvements in the technology of reinforced concrete in the last several decades. Two of the most important are the use of non-metallic reinforcements and the use of self-compacting concrete. The most significant use of non-metallic reinforcements has been the application of fiber reinforced plastic (FRP) reinforcement for retrofit and refurbishment of existing structures. Recently, carbon reinforced plastic (CFRP) grid has found application in new construction in precast concrete cladding panels, wall panels, and other products. The use of self-compacting concrete together with grid makes the production of very thin and lightweight panels practical. Furthermore, development of very lightweight concretes using waste materials for a significant portion of their volume adds the possibility of making still more economical precast concrete panels. The use of lightweight concrete panels in applications such as single and multi-family housing and wall panels for metal buildings become economically viable. Therefore there is a need to develop an understanding of the behavior of these new materials and to develop design procedures and standards as well as further improvements in the materials themselves. Specific topics include: Fatigue – Fatigue of FRP reinforced concrete is critical because little is know about this topic. In addition, CFRP Grid has additional concerns that are not an issue with CFRP rebar. These include the dependence of cross-shear strength for bond, development, and splices, as well as local curvature at cross-over points which could lead to reduced fatigue strength; Durability – Durability of CFRP grid should be similar to other types of FRP reinforcement with the exception that cross-shear strength is a resin property and will be more susceptible to durability issues than normal rebar; Shear – Grid can be used both for shear transfer in composite panels and shear reinforcement for thin walled sections. Appropriate design methods are needed; Connections – Connections of thin lightweight CFRP grid reinforced precast panels must be developed and tested. Appropriate design methods must be developed; Panel systems – Panel systems for floors, walls, and roofs that can be used for a variety of applications such as cladding metal buildings and for complete precast single family and multi-family housing need to be developed and tested. ICC approval needs to be obtained.

Prof. Gudmundur Ulfarsson - Assistant Professor & GAANN Advisor

Roadside hardware is meant to prevent fatal injuries from collisions with more dangerous fixed objects such as utility poles, and trees, however, they themselves contribute to fatality and disabling injury risks. Significant work has been done in the area of controlled crash-testing of roadside hardware to assess their effectiveness in run-off-the-road crashes; still, there remains the need for further research on the in-service performance of roadside hardware. Much uncertainty remains on how the combination of factors often encountered in-service, results in injury severities. For example, collision angles, roadway characteristics, variations in driver characteristics, environmental conditions at the time of the crash, as well as hardware condition and its interaction with vehicle type may contribute to inferences not normally available from controlled crash testing. This proposal attempts to provide a complement of knowledge from an in-service perspective to roadway engineers. Perhaps, when critical mass is achieved in both areas (crash-testing and in-service analysis), roadway engineers may be in a position to identify gaps in roadside design, and improve public safety while minimizing hardware lifecycle costs.

The research facilities available to support the ongoing research programs include: