New to AASHTO and Bridge design, please help me

[saruncivil]

Hi engineers,

I need your help to do my job in right way.
I got one bridge design (my 1st bridge design job), which is curve steel bridge. I had chosen the AASHTO specification for design. I had calculated the dead load, live load due to vehicle, construction load and still what are the forces I have to consider and how to calculate, please advice.
I am doing the analysis and design of bridge with the help of STAAD PRO V8i, I had tried the modeling and design, I got this warning “ **WARNING** EITHER FLANGE WIDTH-THICKNESS RATIO OR WEB HEIGHT-THICKNESS RATIO” what I wanna do please advice.
Please advise me in common about bridge design, please engineers.
Looking ahead for your help and guidance.

Arun S M.E
saruncivil@gmail.com

 

[msquared48]

These are questions that you should be asking your supervisor. Don't you have someone who can mentor you on something as complicated as this? Seems like a pretty complicated structure for no mentoring help first time out of the chute...

Mike McCann
MMC Engineering

 

[engidude]

FHWA GUIDES and eaxmples: FHWA-IF-12-052, FREE TO DOWNLOAD.

I have not done a curve steel bridge yet.

 

[saruncivil]

engidudu, thank you for your reply with useful materials and i had downloaded and reading.

msquared48, you are right. this is the 1st bridge job to our office and no one aware about this so only i look all of your kind guidance and help, so that i can learn and gain knowledge from experienced and world class engineers like you.

 

[engidude]

It is big task for a fresh hand to do a curved steel bridge.
we could have done one two years ago in MISSISSIPPI, but managed to avoid it in the lay-out stage after coordinating with roadway guys.
it was a long bridge, with two steel spans in the middle, two opposite direction horizontal curves and vertical curves. we avoided horizontal curves on steel spans knowing that it would be much easier to deisgn steel spans

 

[bridgebuster]

I don't have my AASHTO with me, and I never used STAAD for bridge design, but it sounds like you're model doesn't comply with the geometric requirements in AASHTO.

Curved girder design is nothing to be afraid of. Although if the bridge is being constructed in stages it can be tricky.

 

[VoyageofDiscovery]

Your situation seems crazy to me, if you are designing a bridge you need someone experienced in bridges to oversee and take responsibility. Though codes today make it seem cookbook, it is not, as there are things not obvious! For example, just to scratch the surface, to correctly model a low radius curvature it will require FEM as oppose to 2D analysis.