This Week's Featured Presentation
Seismic Rehabilitation—From Analysis to Practical Application (ACI Fall 2018 Convention, Las Vegas, NV) This presentation will provide an overview on an ongoing NIST funded project that is managed by the Applied Technology Council (ATC), concerning benchmarking of existing buildings evaluation methodologies. The objectives of this project are to: (1) benchmark ASCE 41 evaluation procedures with respect to the data recorded for reinforced concrete buildings subjected to actual earthquakes or tested experimentally on a shake table, and (2) compare the evaluation results predicted by ASCE 41 with Eurocode 8-Part 3, ATC 78, and New Zealand guidelines on evaluation of existing buildings. A suite of eight reinforced concrete buildings including moment frames and shear wall buildings, are identified where detailed design information as well as data from laboratory testing or field reconnaissance data of damaged buildings are available. The response of these buildings is assessed using the available evaluation methodologies, and the damage predictions from each methodology is compared against observed damage. The results will be used to identify strengths and weaknesses of each evaluation methodology in simulating the real performance of the building. The outcomes of this project would lead to recommendations for improving evaluation procedures in ASCE 41. This presentation will be followed by three case studies that are under development as part of this project.
January 27 - February 2
Rehabilitation of Longitudinal Joints of Double-Tee Girder Bridges
by Lucas M. Bohn, South Dakota State University; Mostafa Tazarv, South Dakota State University; and Nadim I. Wehbe, South Dakota State University
Seismic Repair and Retrofit of Concrete Bridges (ACI Spring 2018 Convention, Salt Lake City, UT) Prestressed precast double-tee (DT) bridges are the most common type of bridges on South Dakota local roads. They are also common in the neighboring states. Longitudinal girder-to-girder joints of many of DT bridges have deteriorated after a few years of service mainly due to insufficient detailing. Twenty joint rehabilitation alternatives were developed and two were selected for bridge system testing: (1) a continuous joint reinforced with wire mesh and filled with latex modified concrete (LMC), and (2) discrete pockets reinforced with steel bars and filled with ultra-high performance concrete (UHPC). A 50-ft long full-scale conventional DT bridge was constructed and tested under AASHTO fatigue loadings. The longitudinal joint of the bridge was subsequently rehabilitated using the two detailing, each was incorporated on one-half of the bridge length. Fatigue and ultimate testing of the rehabilitated bridge showed that the both proposed joint rehabilitation methods are structurally viable.
The presentation highlights the detailing and performance of both conventional and rehabilitated DT bridges, and a summary of findings will be presented.