Return to index: [Subject] [Thread] [Date] [Author]

Re: Golf Course Bridge

[Subject Prev][Subject Next][Thread Prev][Thread Next]
What I do for checking simple span prestressed bridges is essentialy the
same; at any given point of the span, the maximum moment is when you
have a concentrated load above it. With this , you can create a
spreadsheet to check actual vs. allowable stresses, and modify thecable
trajectory. At the end, yoy check moments for demand/capacity ratios.

Effland, Greg wrote:
> 
> Correct, a good SHORT discussion on this is ASD 9th Edition page 2-310
> at the bottom "General Rules for Simple Span Beams Carrying Moving
> Concentrated Loads"... This theory may have to be expanded to true
> influence lines upon multiple uneven spans.  But it works good for
> simple span beams.
> 
> Greg Effland, P.E.
> KC MO
> 
>      -----Original Message-----
>      From: Cain, William [mailto:bcain(--nospam--at)ebmud.com]
>      Sent: Tuesday, June 05, 2001 12:36 PM
>      To: 'seaint(--nospam--at)seaint.org'
>      Subject: RE: Golf Course Bridge
> 
>      Brian-
>      Actually finding the maximum moment without a computer is
>      not all that difficult if one uses influence lines.  If you
>      place the midpoint between your heaviest load and the center
>      of gravity of all the loads that will be on the bridge at
>      the maximum point on the moment influence line, that will
>      produce the maximum moment in the girder.  Of course, since
>      the EIT after your signature on a prior posts indicates that
>      you have probably been educated since advent of the frequent
>      use of the computer for structural analysis, you may not
>      have learned influence lines.  Refer to most any text on
>      indeterminate analysis such as Norris and Wilbur or Kinney
>      for a discussion of this technique.  It will give you a much
>      better feel for the structure than reams of computer
>      printouts.
>      Regards,
>      Bill Cain, SE
>      Oakland CA
> 
>           -----Original Message-----
>           From: Brian M. McMahon
>           [mailto:brian(--nospam--at)ubsdesign.com]
>           Sent: Tuesday, June 05, 2001 9:43 AM
>           To: seaint(--nospam--at)seaint.org
>           Subject: Re: Golf Course Bridge
> 
>           Eric,
> 
>           Finding the maximum moment for the girder(s) with
>           the vehicle load is somewhat tricky, especially by
>           hand (without computer software).  If you use a
>           10K vehicle you can check me with the follow
>           equations:
> 
>           Assumption: Back wheel = 4K and front wheel = 1K
>           (Spacing between wheels is 5'-6" and wheel span is
>           11'-0")
> 
>           Hint: The CG of the vehicle is 1.1 ft left of the
>           center line of the span, L/2 (that would be the
>           rear wheel)
> 
>           M = 1.25*L + 6.05/L - 5.5 K*lbs
> 
>           R (left support) = 5 - 5/X - 11/L
> 
>           X is the distance from the left support to the
>           center of the back wheel.
> 
>           Make sure you prove these formulas before using
>           them.  It's been a while since I derived them.
>           But, I had them written down.
> 
>           Thanks to Bill he knew the word Bollards for those
>           metal posts at the end of the bridge.  Space them
>           as required.
> 
>           Don't forget to buy your AASHTO manual.  You'll
>           pay for it with your first bridge.
> 
>           Good luck!
> 
>           Brian McMahon
>           Timber Design
>           Universal Building Specialties, Inc.
>           Auburndale, Florida 33823
>           (863) 967-1131
> 
> 
> 
> 
> 
> 
> 
> 
>                ----- Original Message -----
>                From: T. Eric Gillham PE
>                To: seaoc list
>                Sent: Monday, June 04, 2001 7:55 PM
>                Subject: Golf Course Bridge
> 
>                I am designing two cart path bridges for
>                a golf course.  First bridge is 3 span
>                70'+50'+50', second bridge has a single
>                span of 70'.
> 
>                Wonder of wonders, the owner and the
>                contractor both want to minimize the
>                cost on the structures, and are asking
>                that I use the minimum live loading
>                possible.
> 
>                The largest vehicle used on the golf
>                course is a mower/utility vehicle with a
>                gross weight of about 2 tons, well below
>                H15 loading.  The bridges themselves are
>                to be 10 feet wide, and the approaches
>                are so hilly that it is unlikely that  a
>                truck could even get to the bridges.
> 
>                Soooo, my question is : Does anyone have
>                experience regarding the use of loads
>                substantially less than those required
>                by AASHTO for the design of NON-highway
>                bridges.  If so, are there standard
>                loads?  I was thinking of using 5 tons
>                as a minimum, and having the owner post
>                a permanent sign showing the weight
>                restriction.
> 
>                Also, does the AASHTO manual govern the
>                design of the bridges?  We are currently
>                under UBC94, soon to switch to the IBC,
>                but I am not all that familiar with
>                AASHTO requirements (not much bridge
>                work on Guam).  I would prefer to use
>                UBC94, LRFD 2nd Ed for the girders, and
>                refer to AASHTO for load distribution
>                (based on 5 ton total weight) and
>                seismic design.
> 
>                Any suggestions?
> 
> 
>                T. Eric R. Gillham PE
>                PO Box 3207 Agana Guam 96932
>                Ph:   (671) 477-9224
>                Fax: (671) 477-3456
>                Cel  (671) 687-7115
> 
>                teric(--nospam--at)gk2guam.com
>


* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org