PPC I beams vrs Steel
PPC I beams vrs Steel
(OP)
Has anyone come across a guide, ie. table, software, spreadsheet, that compares a steel beam, and its span length and spacing, to a precast prestressed concrete beam, or vice versa?
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
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RE: PPC I beams vrs Steel
RE: PPC I beams vrs Steel
Beyond the theory, however, it really depends on what the state is doing in that particular region that may dictate what is most feasible. For example, if a state does predominately steel in a certain area, it may be hard to find a pre-caster or better yet some one certified to do pre-cast concrete.
Items which raise the cost of steel are material and fabrication cost, framing (no less than 25') which leads to a lot of miscellaneous hand welding - labor cost, bearings are more expensive for steel girders, initial painting shop and field coatings, and finally the maintenance cost for painting etc.
Concrete has benefitted from the torsional properties by reduced framing. Material cost are lower as are fabrication cost. Bearings are usually nothing more than neoprene pads (no sole plates and bolts required) mainly becuase they are cast into a diaphragm monolithic with the deck. Little maintenance is required over the life of this type of structure.
Yet, given these items, Concrete is rarely used on standard applications beyond 100'-120' spans. Generally, steel plate girders are then used. Though, if the logistics are right (local pre-caster, contractor, engineer) then concrete may be used in excess of those lengths.