In boom times and flat times, construction is a dangerous
trade. And the greatest risk sometimes falls on the people
doing the dirtiest physical work. From the
Southampton, New York, Town News comes this sad
story:
"A construction worker died in Southampton Village on Monday
afternoon when a foundation wall at a work site collapsed,
pinning him underneath .... Facundo Gonzalez, 33, of
Farmingville was trapped beneath the fallen concrete wall
shortly before 3 p.m. while he was working at a construction
site at the southeast corner of North Sea Road and Willow
Street."
The Town News quotes local building official Jon Foster as
saying that Gonzalez was excavating beneath a recently poured
concrete wall to install footings that, according to code,
should have been installed before the wall was placed. Also,
said Foster, the wall lacked steel reinforcing that should have
been included, and might have prevented the structural
failure.
It's worth noting that in some cases, it's okay to pour a
basement wall without footings, and with just a minimum of
steel rebar. The latest authority for residential basement wall
design is an American Conscrete Institute standard called ACI
332-08, "Requirements for Residential Concrete Construction,"
available from the
ACI
bookstore for $58.50. The standard specifies footing widths
based on the load-bearing strength of the soil, and on the load
imposed by the foundation wall and the house. Sand or gravel
soil, such as you'd find on most of Long Island, New York, may
be strong enough to support some basement walls even if the
spread footing is no wider than the wall itself. The same could
be said of many coastal areas where sand and gravel soils
predominate — although, in low coastal areas, it's
also important to watch out for spots with soft or unstable
silt and clay soils, or even peat (and, of course, uncompacted
fill placed by people).
But even when the site soils are strong, it's a different story
when you undermine the wall, as happened in this case
— or if the wall has to span across a small area of
uncompacted fill. In such cases, the wall, with or without a
footing, needs horizontal steel reinforcement (which this wall
reportedly lacked).
There's a good discussion of basement walls and footings in the
archives of the Journal of Light Construction in two articles
written by engineer Brent Anderson, who helped write the ACI
332 standard. Anderson explains how to properly size footings,
and where to place rebar to maintain wall strength in order to
span localized zones of soft soil.
Detail from
"
Designing Concrete Basement Walls," JLC April
2002
Detail from
"
Footing Fundamentals," JLC October 2000
In hindsight, most catastrophes are preventable. A series of
events had to happen in order to cause the death of
construction worker Facundo Gonzalez. The wall had to be placed
without a footing and without reinforcement — a
decision that local building officials are looking into. Then,
Gonzales had to be given the dangerous task of digging
underneath the wall to retrofit a footing, with no measures in
place adequate to ensure his safety — an event that is
under investigation by New York OSHA. And in this case, the
death has also been reported to the Suffolk County, New York,
homicide squad, which Southampton Village Police said is
routine in any case of an unnatural death.
None of this, of course, will bring Facundo Gonzales back to
life. But for the rest of us, there is still time to learn the
lessons, and to be careful that the same thing does not happen
on one of our jobs.