012925 CSCE Dinner Meeting at the University of Hartford - Earn 1 NYS PDH

Please join CSCE on Wednesday, January 29, 2025, for its monthly dinner meeting at the University of Hartford to hear David Jacobs, Ph.D., P.E., F.ASCE, give a presentation on Live Load Impact on Railroad Bridges. This meeting is co-sponsored by the CT Chapter of the ASCE Structural Engineering Institute and the ASCE Student Chapter at the University of Hartford and attendees can earn 1 NYS PDH at this event.

The rating section of the American Railway Engineering and Maintenance of Way Association’s (AREMA) Manual for Railway Engineering (MRE) gives a formula for a curvilinear reduction in the design impact factor based on train speeds below 60 mph (96.6 km/h). A novel study to measure the actual change in dynamic impact force produced by modern passenger equipment as a function of train speed was conducted by measuring the deflections, strains and accelerations of several truss and floor system members from live loads. The test structure was a 120-year-old open deck through truss bridge. Data were recorded from two different types of electric passenger trains with speeds ranging from approximately 5 to 40 mph (8.1 to 64.4 km/h).

Test results indicate that the impact reduction relationship relative to speed for the types of vehicles used in the study is significantly different from that called for in the MRE’s reduction formula. This result, and reasons for it, which will be discussed, could have significant ramifications for extending the service life of existing, very old railroad bridges, where the predominant live load is passenger equipment, such as on Amtrak’s Northeast Rail Corridor between Washington, D.C. and Boston, MA.