Interesting Wind Test
Interesting Wind Test
(OP)
See the following link for an interesting wind test. Particulary, note the masonry wall failure... uplift, and a shear wall failure!
http://www.wbtv.com/story/20546899/commercial-buil...
http://www.wbtv.com/story/20546899/commercial-buil...






RE: Interesting Wind Test
The key is continuity of the structural components.
I saw my first engineered design fail because of the unpredictable loads that occurred. It was a reinforced masonry blast resistant structure that contained computers and instrumentation closely facing the direct blast of a rocket engine for a 5 to 7 minute engine test and it performed for daily tests for a month or two. The walls were partially reinforced 8" concrete block with many narrow 4 pane bullet/impact resistant glass for observation in addition to telemetry. One day during a normal purge of the fuel/oxidizer tanks about 300 feet away, a hydrogen "bubble" floated over the several bunkers and a static spark set off a blast several hundred feet above and blew the roof (2x12 at 12" on center with twp layers of 3/4" plywood, insulation and roofing on the top and one layer of 3/4" on the interior. the blast blew the roof down on top of 50 or more computer stations. The next day all other block houses had bracing installed on all other instrumentation boxes.
The company and the associated partners had all the money necessary to solve anything if it could possibly be predicted and there was no lack of support. WE even instrumented rocket test stands with accelerometer at every joint 24/7 for a month or so to determine the short term effects of rocket firing in addition the later seismic effects on a fully loaded stand (most loads down), and during a firing (highly variable vertical loads plus vibration from a gimballing engine) and unloaded stands. We got an airframe program from sister company to determine the reaction of the structure and then applied the reaction to the steel frame to the current AISC loading and allowables. - That was in the 1960's space race pioneering period and it was a pleasure to work in an environment that encouraged education and research in many areas. - It made me realize the importance of continuity and unpredictability of loads.
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Interesting Wind Test
RE: Interesting Wind Test
It was definitely the wall perpendicular to the wind, but I could be wrong about shear failure. I'd need to look at it again more closely. the diagonal cracks started forming, and then the entire wall blew out, probably from internal pressure + external suction. maybe it didn't keep moving because the building was still braced on three sides?
RE: Interesting Wind Test
If we designed a masonry building in Australia with a single bar in each corner and practically no tie down (fixings to tie the roof to the footings) we'd end up in Jail!
I've had houses I have designed stand up to 200+ km/h winds :)
RE: Interesting Wind Test
The only thing "common about that construction is that it was "common in older structures in the US prior to 1970 and in many second and third world countries now. It is not a "common" form of new construction where I practice.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Interesting Wind Test
Per the UBC's (1988 and 1994 that I checked) 90% of the country was 90 mph or less wind load and 25% at 70 mph.
The building that was damage, per the National Weather Service was hit by a microburst. How many engineers are designing small buildings to withstand a microburst? I am not, unless the owner requests it. Though, I do put verticals at 8' o.c. maximum for my masonry walls.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Interesting Wind Test
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Interesting Wind Test
Sorry, but I think that test may have been a waste of money for someone - but it is a dramatic example of how easy these buildings can go down when they may only be at the edge of a big wind.
A few years ago a local engineering firm who had been back east doing some investigations after Katrina had brought back pictures of school buildings damages. It was awful and some of us think that it criminal that these kind of buildings are still built.
The worst thing that still haunts me was a group of people taking shelter in a modern unreinforced concrete block church and the building came down around them. This is within that last ten years. Looking closely - no bar anywhere. That building was almost like the building that wasn't reinforced.
Sorry for the rant. It's 41 years today for the firm.
RE: Interesting Wind Test
Per the UBC's (1988 and 1994 that I checked) 90% of the country was 90 mph or less wind load and 25% at 70 mph."
Remember though, that was a new building. some deterioration of just the trim allows wind inside the fabric and hastens the destruction.
Michael.
Timing has a lot to do with the outcome of a rain dance.