Exclude lane loading?
Exclude lane loading?
(OP)
I am a recent grad, entry level structural engineer. A problem recently came up at work, where a client wants to drive a 6-axle, 180k drill rig over a 75ft span single lane bridge (with ends fixed in concrete headwall).
Is it ok to analyze this bridge assuming a single pass of the drill rig with no other applied loadings (i.e. do i have to apply the 640plf lane load specified in aashto lrfd)? I was under the impression that this lane load is for cases involving a train of hs-20 trucks, one after another. However a single vehicle making a single pass would only require one wheel line traveling on top of one girder (multiplied by a load distribution reduction factor). Is this correct?
I have found the girder to be over capacity with the lane load applied, and under capacity without the lane load, which is why i ask.
Thanks for all your help!
Is it ok to analyze this bridge assuming a single pass of the drill rig with no other applied loadings (i.e. do i have to apply the 640plf lane load specified in aashto lrfd)? I was under the impression that this lane load is for cases involving a train of hs-20 trucks, one after another. However a single vehicle making a single pass would only require one wheel line traveling on top of one girder (multiplied by a load distribution reduction factor). Is this correct?
I have found the girder to be over capacity with the lane load applied, and under capacity without the lane load, which is why i ask.
Thanks for all your help!





RE: Exclude lane loading?
RE: Exclude lane loading?
We have done this before, but I have never had to analyze a bridge for such a heavy vehicle.
The bridge has no posted weight limit, and finding a detailed inspection report is proving difficult. I think the bridge should be fine, but obviously I would like to prove this.
Thnx for your response.
RE: Exclude lane loading?
RE: Exclude lane loading?
RE: Exclude lane loading?
RE: Exclude lane loading?
Thanks again for all your help. Feel free to offer any more suggestions!
RE: Exclude lane loading?
Before you doing anything creative, make sure the code likes the artwork you are trying to wow the world with.
RE: Exclude lane loading?
RE: Exclude lane loading?
In Russia building design you!
RE: Exclude lane loading?
RE: Exclude lane loading?
Also: "but some codes will also allow a reduction in the dynamic load allowance if speeds are limited to certain amounts."
In MD that limiting value is 5 mph.
There is a reason Maryland his an 8% structural deficiency rating...
In Russia building design you!