Impact included in deflection calculation

[EngSD]

When checking a support beam over a rail unloading pit for deflection should I be including the impact factor? I can't find anything in AREMA or the IBC.

Thanks you for any help.

 

[DST148]

Impact is to be used for the strength limit state. For serviceability, in general, unfactored loads without impact is used for checking deflections.

 

[MiketheEngineer]

Usually with a 2X factor - at least in my book

 

[paddingtongreen]

No. The impact is of such short duration, the forces don't have enough time to follow the load paths before they are removed.

Many years ago, my boss checked a railroad bridge by measuring it's deflection. The bridge had been rated for 5MPH by the worried owner, my boss ran a locomotive over it a 5MPH and recorded the deflection (It said the bridge was good). Just to see the effect, he had them run the locomotive over at 30MPH. The deflection gauge didn't see a thing, the load was gone before it had time to stress all the material.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[EngSD]

Thanks everyone for your help!