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Masonry Stands Up to High Winds
Strong winds can occur just about anywhere. Whereas coastal regions
see hurricanes, the middle of the country can be hit with tornadoes.
Few regions are without risk. This month’s Extreme Masonry
series continues with several examples of high wind events and stories
about the structural performance of buildings affected by hurricanes
and tornadoes.
Hurricanes are classified according to the Saffir-Simpson Scale
as categories 1 to 5. Tornadoes are defined by the Fujita Tornado
Scale from F0 to F6. F0 and F1 tornadoes are called weak tornadoes;
F2 and F3 are called strong; and F4 and F5 are called violent.
|
Hurricanes |
Tornadoes |
| Category |
Wind Speed,mph |
Damage* |
Class/Type |
Wind speed, mph |
Damage* |
| |
|
|
F0, Gale |
40 to 72 |
light |
1 |
74 to 95 |
minimal |
F1, Moderate |
73 to 112 |
moderate |
2 |
96 to 110 |
moderate |
F2, Significant |
112 to 157 |
considerable |
3 |
111 to 130 |
extensive |
F3, Severe |
158 to 206 |
severe |
4 |
131 to 155 |
extreme |
F4, Devasting |
207 to 260 |
devasting |
5 |
more than 155 |
catastrophic |
F5, Incredible |
261 to 318 |
incredible |
| |
|
|
F6+, Inconceivable |
319 to 379 |
wind speeds are not expected to reach F6 levels |
| *For more description of
the effects of damage, see Hurricane
Categories and Tornado
Statistics |
Hurricanes are not unusual in Florida; they have their own season.
The last ten years have given us many seasons to remember, and many
names, too. Andrew in 1992 (Category 4), Opal in 1995 (Category
3), Georges in 1998 (Category 2), Irene in 1999 (Category 1), and
Charley in 2004 (Category 4), to name a few.
 Charley
went through Port Charlotte, but this home that was under construction
shows no apparent damage, other than a few missing and damaged shingles
on its roof. The concrete masonry building is topped with wood trusses
and clay roof tile. (Photo courtesy of The Masonry Society.)
 The
Twin Cinemas in Van Wert, Ohio, were struck by an F4 tornado on
November 10, 2002. As the left side of the photo shows, much of
the building was ripped apart by the tornado. Luckily for the patrons
in the building at the time, the theater manager moved them into
the concrete masonry restroom areas for safety before the wind hit.
Such incidents have prompted many homeowners and builders to construct
“safe rooms.”
Reinforced concrete masonry is a natural for such construction.
(Photo courtesy of The Masonry Society.)
Masonry walls, especially those that are reinforced, stand up well
to high wind forces. They have the ability to resist wind blown
debris when solidly grouted. Investigations have identified specific
recommendations to improve building performance. Notably, strengthening
the roof to wall connections in masonry structures, use of reinforced
masonry, and adherence to design and construction criteria of ACI
530/ASCE 5/TMS 402 would allow buildings to weather high wind events
with minimal damage.
Further Reading
Performance
of Roof Materials
Hurricane
Andrew (PL363)
Hurricane
Fran (PL371)
Hurricane
Opal (PL370)
Hurricane
Opal TMS report
Further TMS
Reading:
| Title |
Authors |
Published In |
| Failures of Unreinforced Masonry Structures During Hurricane
Hugo |
Walkowicz and Snyder |
Proceedings of the Sixth North American Masonry Conference,
Vol. 2, June 1993 |
| Hurricane Alicia Tests Materials in (Materials in) Houston’s
Skyline |
J.G. Borchelt and F.S. Pongette |
TMS Journal, Vol. 3 No. 2, July-December 1984 |
| Masonry Foundation Wall Systems Under Combined Uplift and
Shear Forces |
W.M. McGinley and M.J. Scolforo |
TMS Journal, Vol. 15 No. 2, December 1997 |
Performance of Masonry in Hurricane Fran,
September 5, 1996 |
W.M. McGinley and R.D. Thomas |
TMS Journal, Vol. 17 No. 1, November 1999 |
| Alabama, Ohio, and Tennessee Tornadoes - 2002 |
|
TMS News, Vol. 16 No. 1 January/February 2003 |
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