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bridge type selection

bridge type selection

bridge type selection

(OP)
I'm sure this has probably been discussed before, but I can't find it. What are the pros and cons of AASHTO pre-cast girder bridge vs box beam bridge vs superbox culvert "bridge"

RE: bridge type selection

(OP)
ok, I'll start and assuming very little skew and no horizontal curvature and assuming relatively short overall span, perhaps a few hundred feet...

AASHTO pre-cast girders are
easier to design
shorter span lengths
taller supperstucture / higher overall bridge profile
faster to construct
cheaper

boxed beam bridge
harder to design
longer span lengths
narrower superstructure / lower bridge profile
takes longer to fabricate
more expensive

superbox culvert
less hydraulic capacity than a true bridge
lowest overall profile
more impact on riverbed


 

RE: bridge type selection

AASHTO pre-cast girders
+ allow easier deck forming system ~ PCP's or PMD's
  allow less work on-site than forming Bridge class box culvert
- more $ goes to supplier instead of the contractor and local economy

box beam bridge
+ faster construction on-site
- more $
- normal lengths are 100 LF and less

Bridge class culvert
+ more $ to be made (or lost) by the contractor on-site and the local economy
(takes the supplier out of the equation)
- takes considerably longer to construct (in most cases)
- seasonal and more weather dependant
 

RE: bridge type selection

(OP)
if I go from 6 span AASHTO Type 4 at approx 100 ft per span (600 foot total length) to 5 span AASHTO Type 6 with 120 ft span I am saving a lot of money on a proposed bridge. Anybody want to venture a guess how much?

RE: bridge type selection

cvg


Off the top of my head with no verification.

The type 6's we have seen... utilized inverted-T (interior) caps...so the cap(s) are more $.
The 6's obviously cost more. (than 4's)
Eliminating a span (8?) of beams, as well as a bent of foundations, columns, and cap.

A little more labor utilizing the 6's.
They are significantly more unstable.
Bracing will be a little more.

Assuming the design for the foundations, columns, and caps would change a little...appears that it would be cheaper to go with the Type VI Design.

So ...... how much cheaper?
 

RE: bridge type selection

(OP)
104' wide bridge with superelevation

would be eliminating 1 set of drilled shafts, pier caps, piers and approximately 18 girders.

Circular/multi-column piers with dropped-type pier caps or hammerhead piers are recommended at the pier locations. Inverted tee pier caps can be used; however this type of pier cap was not recommended due to increased cost. drilled shafts are the recommended foundation type.

RE: bridge type selection

So ...... how much cheaper?
 

RE: bridge type selection

(OP)
thats my question

RE: bridge type selection

$12,667.21  

RE: bridge type selection

I am looking for some help on assessment of post tensioned box beam bridge.I have modelled it as a 2D Grillage.How can i analysis the web & diaphragm stressess in it?

Any help will be appreciated.
 

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