H&H was selected by Chicago South Shore & South Bend Railroad to evaluate 13 existing bridges for their ability to carry 286K cars in the future. Project included bridges of various types, including a 272-foot through-truss span, deck-girder spans, and through-girder spans.  The lengths of the girder spans ranged from 22 feet to 150 feet.  The ages of the bridge varied up to 102 years.

H&H performed a physical inspection of the bridges to determine section loss; performed normal and maximum load rating calculations for Cooper loading, 286K cars, and GE Dash 9 locomotives; calculated remaining useful life for each bridge, and identified repairs that would be necessary to upgrade bridges to the desired rating level.

H&H provided a report to detail all of the findings including load ratings for each bridge based on the loadings indicated above for the original “as constructed” condition and the current “as inspected” condition. The report also presented the controlling member(s) for each rating scenario. Determinations of remaining useful life were based on current manifest traffic and on assumed numbers of 286,000 cars in multiple future scenarios.