Yjung,
Is this procedure outlined in the manual you're referring to? Could you please share the reference information for the manual.
I don't have a problem with conservative approaches. But that wasn't my question. I'm just trying to see if anyone can tell me exactly what the code wants us to...
Rowe,
Consider a 200ft span. More than one truck could theoretically fit onto this span. Here are the max. moments:
One HS20 truck: 3322 k.ft
Lane loading : 4100 k.ft
Two HS20 trucks : 5855 k.ft
By AASHTO table : 4100 k.ft
Hence it is clear that the AASHTO table has considered only one truck per...
Rowe,
Your para 2 statement - ("as many truck loads (aka axle loads) shall be placed ALONG a 12 foot lane (in the longitudinal direction) to produce the maximum stress for whatever component you're designing.") - doesn't gel with AASHTO max. moment and shear tables (App.A).
In the...
I've found the easiest way is probably to discretize the beam into sufficient number of straight segments, and run it on the computer. Avoids complicated equations that you don't understand and can't rely on. Make sure you get the support conditions right.
Qshake,
I appreciate and accept your clarification, and that you meant well; and there may even be people here who need and have the time for your advice on ethics, but I only visit this website for serious technical discussion, and to learn from the technical knowledge others may have.
So...
Aside of qshake ("For the maximum load on the pier you would load each span simultaneously to arrive at the max reaction. This isn't to much of a strech to visualize assuming, of course, the spans will accomodate the trucks length."); and rowe ("I would place a truck load on each...
Friends, 2 trucks per lane doesn't gel:
If its only one truck per lane for continuous spans, then why not for simple spans? How does the loading know whether the structure is simple or continuous?
If we had a pier that was designed to support 2 continuous spans of 75', and the spans needed...
Lets say we have established the Inventory and Operating Level Ratings for HS20 trucks. For example, lets say they are 1.1 and 1.8.
Now, there is a construction project which needs a heavy crane to be placed on the bridge. This crane causes effects equal to 1.7 times those caused by HS20...
Thanks for responding once again, Qshake. However, you don't seem to be addressing the questions asked.
In evaluating an existing bridge to determine if a certain construction equipment may operate on it, can one use the Operating Rating Level? This would allow a live load factor of 1.3, as...
It seems, Koodi, you're really concurring that there is no need to consider 2 HS20 trucks in the same lane.
To summarize, the maximum reaction on the pier beam should be computed by considering, in each lane, the larger of a)lane load of 640 lb/ft (times tributary length) plus the appropriate...
Can anyone suggest a reference which will provide clear guidance on circumstances in which one may use the Operating Rating Level?
The AASHTO Manual is not quite clear. It seems to be saying that the O.R.L. should be used for an extreme circumstance. Can construction loads from heavy rigging...
Qshake,
About the end-to-end trucks. As you say, the lane loading is intended to cover that possibility. So, assuming one is considering the lane loading case, as required by AASHTO, then does one additionally look at the HS20 trucks back to back in each lane?. If so, what would be the minimum...
For a highway bridge pier supporting simple spans on either side, should the pier be designed for one HS20 truck per lane (positioned right above the pier for maximum total reaction), or for the sum of the maximum reactions from the spans on two sides?
The latter implies two trucks being...
