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Re: Roof collapse

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> From: Chanel1096(--nospam--at)aol.com

> Roof Falls In on Fairfax City Firehouse

> Workers from Colbert Roofing Corp. and Bradco Supply Corp., both of 
> Springfield, were preparing to renovate the roof of the 22-year-old station
> at 10101 Lee Hwy. and had hoisted several tons of shingles and other supplies
> atop the building. Shortly after 10 a.m., the roof gave way, sending the

Several TONS of shingles!

> Jerry Colbert, president of Colbert Roofing, said that employees from both
> his company and Bradco were involved in hoisting materials to the roof and
> that he was unsure what caused the collapse. Bradco officials declined to
> comment.

Obviously, Bradco officials have already talked to their lawyers :-) 

What are the chances that Colbert or Bradco have (structural) engineers
on their respective staffs?

> Ok, this kind of thing happens and it seems pretty obvious what happened but
> my question is what if anything can we do to avoid this circumstance during
> construction.  Here at my office we include the standard Contractor 
> responsible for construction loads, etc.  How well does that really protect
> us?  What do others do to address construction loading, if anything?

At the NASCC in March, there were some comments with regard to the
new-fangled equipment that is being used to build roofs and the
techniques and loads that are applied. When was the last time that
anybody checked the wheel loads of a motorized, rubber tired, gravel
hauler on BUR against the tabulated three span UDL load tables for roof
decks. Is this the designer's responsibility or the contractor's?

Construction loads are 20psf for roofs, right? (he says innocently)

In a similar case; I'm currently developing a retrofit for an industrial
floor trench cover that was designed for a light warehouse tow-motor.
The designer forgot the 14 Ton forklift that would be bringing in the
process equipment.

-- 
Paul Ransom, P. Eng.
Civil/Structural/Project/International
Burlington, Ontario, Canada
<mailto:ad026(--nospam--at)hwcn.org> <http://www.hwcn.org/~ad026/civil.html>