Hello,
I was hoping that someone could point me in the right direction. I am a one man show engineering firm and my main focus is temporary works for bridge construction.
Because AASHTO Temporary Works rarely (if at all) requires LRFD, I have never learned how to do LRFD. This hasn't been a...
More great questions. The bridge was originally designed to handle a Link-Belt 218 crawler crane (see attached drawings). The contractor now wants to deliver concrete via the bridge. The beam spacing was originally designed to accommodate the crane, therefore the beam spacing needs to remain...
Great questions. Attached is sketch. Concrete trucks will drive across this temporary bridge. The liability is mine.
I am aware that I could easily double the mats, or place timbers (or even steel plates) longitudinally under the wheel paths. The cost of the materials gets very high very...
Spanning 4' and using ¾" Class 1 Plyform, Fb=1500± psi, the maximum load you'd want to place on the plyform would be around 20 psf which isn't much if you are moving equipment over it.
You would most likely need joists or some other support under the plywood and space it at whatever your load...
Hello,
I am performing a design check on timber crane mats that will be used in a bending application. In the literature provided by the material supplier (attached), Fb is not given.
The properties given are Static Bending Properties, ie, Modulus of Rupture, Modulus of Elasticity, Work to...
The timbers are made primarily from oak. I am familiar with NDS, but didn't trust it for this application because the numbers differ greatly between NDS and what the supplier says the mats are made of (attached).
For instance, the values in NDS for shear parallel to the grain for oak is...
Here's the other attachmenthttp://files.engineering.com/getfile.aspx?folder=2708504a-2ba3-436d-bf6d-a54972cb000a&file=Chap_4_-_Strength_Properties__-_partial.pdf
The paper was outstanding. Thank You!
I have another question if you can help me...
For checking bending stresses, I would typically compare the actual bending stress, fb=M/S to the allowable, Fb. However, in the literature that I was given from the material supplier (attached), Fb is not...
That's a great point. If the timbers are bolted together, the mat would act as a unit distributing the half axle (tire) load over two 12" timbers.
Thanks for the help!
Thanks a lot! That's a huge help.
Actually, I designed the bridge to handle a Link-Belt 218 crawler crane. The sideframes are centered over each girder pair (so there is(was) only compression on the timbers). I wasn't worried about the timbers until the contractor mentioned to me that he...
I am checking the adequacy of 12" x 12" timber crane mats being used as the deck for a temporary construction work bridge. I am not sure how to apply the tire loads to the deck.
This is my first post, so I will attempt to attach a sketch.
The tire load is 12,000 lbs (concrete truck). The tire...
