Oklahoma sits on hard surface rock, therefore basements are too expensive to dig.
Tornados will destroy a square or rectangular building, long before a spherical building.
Proposal:
Every school in OK should have a steel reinforced concrete spherical radius fallout shelter, that is anchored into the bedrock, with a capacity for 150% of the student and faculty population.
It would resemble a large contact lense, as opposed to a true radial dome ( low profile). In addition to anchors in bedrock, it would have 2 inch diameter twisted cable that draped over its apex, anchored at both ends in bedrock.
This design would dissipate vertical, horizontal and rotational forces.
Counter point:
Schools amazingly still do not require seat belts on buses, so children are viewed as perishable commodities
Good idea? Perhaps we could ask the parents of the 1st thru 3rd graders in OK that were forced into a lockdown in a school that had no basement …who are still missing
It doesn’t make sense to pour time and money into engineering and finding land for a special new type of structure when conventional box-shaped, below-grade concrete tornado shelters are proven and would likely be cheaper and easier to build. In other words, dig a freakin’ basement.
Now, where are we going to get the money for shelters (of any kind)? We already laid off the art & music teachers and the football team needs new uniforms.
July 13, 2004 in Roanoke, IL a F4 tornado hit and leveled a manufacturing plant. 140 people were in the building who where sheltered in three tornado shelters constructed above ground inside the building. the factory had a severe weather plan where spotters were used when severe weather threatened. the people got in the shelters and only minor injuries were had.
i think that more schools in those tornado areas have developed sheltered areas after tornadoes have impacted expanding populated areas in recent decades. tv news did have a comment by a student survivor that they were in a shelter area inside of the school.
If you want to pull this off, you’re going to have to make some adjustments:
instead of requiring all schools in Tornado Alley have it, instead require all new schools have it or something similar. Old schools may be grandfathered in.
find a way to pay for it that doesn’t local residents screaming about increases in property taxes or people in Florida and Washington screaming that it’s not their kids.
find a way to make it multipurpose. You simply cannot have a structure large enough to hold 150% of students, faculty, staff, and visitors in a school without using it for other activities. Make it an auditorium or a cafeteria as well. That opens it up for more funding, more use, and more adoption.
Building a structure like that in every school up and down “tornado alley” would be prohibitively expensive and the chances of any individual one ever being needed is very small.
I’m not saying it’s not worth spending money to make kids safer, but there are better ways of spending money to make kids safer.
As was pointed out hundreds of times yesterday in the media, there are very, very, very few basements or below grade structures in Oklahoma due to it resting on hard bedrock. What few that we’re built, required dynamite. Very expensive.
Yesterday’s events have proven that the current above ground designs have a fatal flaw in an EF4 or EF5.
Perhaps Zago ( I recall she’s an architect ) could offer her opinion. I work in smaller scale mech enrgr, and have used CAD CAE FEA, so I suspect architects have similar tools, where thy could model and test the concept with known EF5 loads.
Not for all of Tornado Alley. Just the geological regions that sit on hard bedrock, like Oklahoma , that make basements more cost prohibitive than a spherical anchored dome.
Indiana was hit by massive tornados last year, remember the kids on the school bus that was slammed into a diner ( the owner has since renamed it “Ed’s Bus Stop Diner”- no kidding). Massive injuries and deaths in that series of tornadoes, that also destroyed schools with kids under lock down.
The difference is, In Indiana I can shovel out my own basement with just a shovel
Carmel Indiana spent $ 11 million for a high school football stadium that benefits only 30 students during one semester.
I have to believe that an anchored spherical shaped shelter will withstand x,y and z axis loads from an EF5 direct hit, better than a rectangular shelter. And possibly, better than an underground shelter, if the floor above is sucked off.
Bonus points to anyone who can link to a study to this effect.
FEMA just paid or 2 above ground dome tornado shelters for mobile home courts, in Ohio.
Cost $400 k each
Capacity: 315 per dome
As I recall, the OKC schools, had fewer than 300 students and staff, at each school.
So a school like Carmel can afford $11 million for a football stadium for the benefit of 30 jocks, but not half a million for the lives of 315 nerds?
ok…Got it.
The spherical structural isn’t by itself going to help. You’re thinking in terms of efficient structure for load bearing. That is part of the problem which can be mitigated with reinforcement techniques like truss clips on current designs. tornadoes will tear down a house with flying debris such as 2x4’s which can easily punch through brick and cinder block.
There are already established engineered structures for the most powerful tornadoes.
They are incredibly energy efficient, as much as 50 % less to heat or cool, which ties into the suggestion above to make them multipurpose
They are less $ to buy and install than underground
They are FEMA rated at 300 mph winds which is 1/3rd more than FEMA requires (200 mph)
They are anchored using Hilti anchors.
I have used Hilti anchors in industry. They are the best. You drill a deep hole into the foundation then set a Hilti expanding bolt in place. Then you pour in 2 chemicals that react and get very hot, then it cools down and solidifies. Then you tighten the anchor bolt which expands width wise into the solid. It is now harder than the surrounding foundation.
Translation: that dome ain’t going anywhere in an EF5 direct hit.
Wait, do you mean to say that there are schools that don’t have tornado evacuation areas? Every school I’ve seen in Cleveland (off the main Alley, though we still get a few) has places for the students to go in the event of a tornado. Sometimes it’s the cafeteria/gym, sometimes it’s the windowless coatrooms adjoining the classrooms, but there’s always someplace. And these are ancient, poorly-maintained, underfunded schools.
Can’t answer your question without crunching the numbers. What is the square footage of the dome and what is it rated for? Does this include installation? Unlike Oklahoma which has a marbling problem with many locations which raises the cost of digging and maintaining a basement, Ohio does not. You could backhoe a hole next to every trailer and drop an oversized fiberglass structure in the ground pretty cheap to handle 4 people. You’re round structure holds true underground and requires less reinforcement.