I am trying to analyze a prestressed girder dated about 1960. The company wants to upgrade the bridge crane from 50 tons to 85 tons.
Does anyone have any information on the prestress used then? How about load tables? I have a copy of a 1971 PCI handbook. The concrete tests showed about 5000 psi.
Design the (assumed) new 85 ton crane such that it imparts the same loads onto the runway system as the existing 50 ton. ie; more end truck wheels spaced farther apart, restrict hoist approach to runway beams (assists with vertical load only). We have successfully put a 30 ton crane on a runway designed for 10 tons by doing this. Additionally. You will find that a new 85 ton hoist will weigh the same or less than and “older” 50 ton. Hoist weight contributes to lateral load into runway beam.
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