Thread: wood for building shoring
12-27-2000, 09:30 PM #1high angleFirehouse.com Guest
wood for building shoring
I was talking to some people about shoring up an building if it was hit by an vehicle They said if need to shore it up the would have the local lumber yard bring what they needed than the I ask the question of what type of wood do you use for these operation? Some of them said hardwood and some said soft woods. I prefe hard wood shoring operation. I like to hear the options from others.
12-28-2000, 08:07 PM #2JStrickTRT1Firehouse.com Guest
According to the FEMA Rescue Specialist Manual the preferred wood for structural shoring is clear, tight grained, southern pine or douglas fir. The author, Dave Hammond, the Lead USAR Engineer advises not to use pressure treated wood. Pine or Douglas fir will show a noticeable compression on the crossgrain, such as where a post rests on the wedges and sole plate on a vertical shore when exposed to an extreme load. Also, PT is usually moist, pine and douglas fir will yield with a cracking noise to give an audible warning before failure, PT may not do this. This is what we were taught at the FEMA Rescue Spec. Train the Trainer.
The National Utility Contractors Association recommends in their Excavation Instructor Manual Douglas Fir or Oak for trench shoring.
The following is my opinion only based on what I have experienced. It is not an easy task getting good clear wood in the South Florida area. Use whatever you can get when faced with an emergency operation. When we responded to Buga, Columbia for an eartquake the only wood was bamboo. Our Task Force engineers could find no tabulated data for bamboo. Via the Internet a testing source was found somewhere in Europe I believe. A piece of the indigenous bamboo was overnighted to the lab and compression tested. I don't have any documentation, but our engineers do. They were impressed at how strong it was. Once again, I am not a registered professional engineer, only a fireman that likes to play with cool stuff,
Any major structural shoring operation must be approved by one of our TF engineers whether at home or abroad. Remember, cities and counties have Building and Zoning Departments that must access an engineer. Meet these people beforehand to find out if they have any knowledge or experience in damaged structures. Just as medics and EMTs must have a Medical Director, it is nice to have a knowledgeable Registered Professional Engineer(the Doctor of the Building) to bounce things off of. And always maintain a posture of rigid flexibility.
Capt. J. Strickland
Miami-Dade Fire Rescue
Special Operations Division
12-29-2000, 11:32 AM #3rsqguruFirehouse.com Guest
I agree with the FEMA training guide offered and I will add that NASA AMES Research Center (part of CATF-3) structural collapse program uses southern yellow pine as a wood of choice. When I attended their training at Moffett Field, we used gantry cranes to load our dead braces made from yellow pine. The braces 6-8 feet tall, held up to 50 tons in testing on a direct reading dyno. attached to the crane.A 4x4 post six foot tall will hold approximately 12,000 lbs. in a straight compression load according to FEMA guides and Airshores manual on structural collapse shoring. The shores we built in CA. failed at the gussets and wedges due to cross-grain being the weak point in the system(the wedges). I have photos of the timbers leaking moisture from the pressue that was exerted on them during testing and at failure. Another important point was the use of the proper nailing pattern into the wood. Once again use the FEMA guide by Hammonds as a guide. Also don't forget, that pneumatic shores are a great asset for structual collapse shoring. They can be placed into a structure for rapid stabilization and then replaced by wood shoring as it becomes available. Here in NC, we use southern yellow pine for structural shoring and trenching operations. The wood has a 1350 psi rating according to the timber guide and meets OSHA specifications for timber shoring in a trench. As with any disicpline, research and education will offer many avenues and choices when deployed to a situation in the field of fire/rescue.
[This message has been edited by rsqguru (edited 01-05-2001).]
01-01-2001, 12:03 PM #4fyrfitr42Firehouse.com Guest
Where can the average Rescue Joe such as myself get a hold of this information? Building collapse and trench is an area that my team needs to research more. There are alot of things that we just take for granted with out knowing the "numbers" to support the theories. Being the sweaty palmed rope head rescue geek that I am, I ask "WHY?" alot. Please help me out.
-Sedgwick County Fire Dept
Tech. Rescue Station #37
-Hutchinson Comm. College
Tech Rescue Instructor
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