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EPICentre Seminar & Discussions: Use of Concrete Filled Tubes in Accelerated Bridge Construction

19 February 2020, 1:00 pm–2:00 pm

111

Event Information

Open to

All

Organiser

Arash Nassirpour

Location

Room 102
Chadwick Building
Gower Street
London
WC1E 6BT
United Kingdom

In urban regions, use of modular construction improves efficiency, reduces errors and costs of structural systems. Typical modular systems utilize primarily precast elements. Although precast systems are advantageous, they require specialized equipment and customized forms. Concrete filled steel tube (CFST) components can replace precast piers and piles with the advantage of simplifying construction (i.e., eliminates the need for a core reinforcing cage and formwork). In addition, for a given cross-section size CFSTs have higher strength and stiffness than RC counterparts. However, design of CFSTs have not been developed and validated to the same extent as other, more traditional construction systems. Shortcomings with current CFST design are: (1) lack of consistent design expressions for the strength and stiffness of CFSTs, (2) need for standard and reliable connections to precast and cast-in-place substructure and superstructure components, and (3) severe underestimate of the shear strength. The University of Washington has been investigating CFST properties and their connections over the past decade, resulting in new design expressions; these expressions that have been implemented in AASHTO specifications and the WSDOT Bridge Design Manual, and are under consideration for implementation by Caltrans. The presentation will provide an overview of the research results, the design methods and expressions and impact on constructability. A system-level, comparison of the seismic performance of CFT and RC bridges will be discussed and used to demonstrate the superior response and resilience of the CFT bridge.

About the Speaker

Prof Dawn Lehman

at University of Washington

Dawn Lehman is a Professor of Civil and Environmental Engineering at the University of Washington. She received her BS from Tufts University in 1989 and her PhD from U.C. Berkeley in 1989. She worked as a structural engineer in Boston MA between these degrees. She has been a faculty member at the University of Washington since 1999. Her research expertise lies in seismic engineering of structural systems. She has conducted research on a range of systems including reinforced concrete walls and frames, steel braced frames, concrete-filled tube frames, as well as concrete-filled-tube, precast and reinforced-concrete bridge systems. Her current research efforts include: 1) new structural systems for vertical evacuation structures in tsunami-prone regions, 2) conventional and new technologies to ensure seismic performance of concrete walls in regions of high seismicity, 3) new design approaches for concentrically chevron special concentrically braced frames, 4) advancing seismic design and construction of bridges and high-speed rail through used of concrete filled tubes and enhanced connections and 5) using real earthquake damage data to evaluate, improve and advance current US codes. She has published over 200 technical journal articles and papers. Her research has been supported by the NSF, Caltrans, WSDOT, Pankow Foundation, ACI, AISC and several other organizations. She is the recipient of numerous awards for her research publications and service to the University of Washington. Her research results have been implemented in codes, design manuals and provisional structural engineering recommendations, including AASHTO, AISC, WSDOT Bridge Design Manual, and ASCE 41.Dawn Lehman is a Professor of Civil and Environmental Engineering at the University of Washington. She received her BS from Tufts University in 1989 and her PhD from U.C. Berkeley in 1989. She worked as a structural engineer in Boston MA between these degrees. She has been a faculty member at the University of Washington since 1999. Her research expertise lies in seismic engineering of structural systems. She has conducted research on a range of systems including reinforced concrete walls and frames, steel braced frames, concrete-filled tube frames, as well as concrete-filled-tube, precast and reinforced-concrete bridge systems. Her current research efforts include: 1) new structural systems for vertical evacuation structures in tsunami-prone regions, 2) conventional and new technologies to ensure seismic performance of concrete walls in regions of high seismicity, 3) new design approaches for concentrically chevron special concentrically braced frames, 4) advancing seismic design and construction of bridges and high-speed rail through used of concrete filled tubes and enhanced connections and 5) using real earthquake damage data to evaluate, improve and advance current US codes. She has published over 200 technical journal articles and papers. Her research has been supported by the NSF, Caltrans, WSDOT, Pankow Foundation, ACI, AISC and several other organizations. She is the recipient of numerous awards for her research publications and service to the University of Washington. Her research results have been implemented in codes, design manuals and provisional structural engineering recommendations, including AASHTO, AISC, WSDOT Bridge Design Manual, and ASCE 41.