Thursday, June 6, 2013

The Bomb Shelter

Part Three

I only needed one ready-mix load but I had four men helping with the pour. We backed the truck to within five feet of the bank, which gave us room for an extended chute, without loading the bank. We planked over the rebar and somehow spread our mass of concrete over and between the mass of slab rebar, vibrated it, tamped it, and rodded it to a rough level. I turned the slab over to the cement finisher with a sense of mission-part-accomplished, and climbed out of the pit. Forming and the main pour still lay ahead but, allowing an hour or so to set, my rebar structure would be based in concrete, no longer hanging in space.

The next week, I ordered out a concrete-cutting sub, who made short work of cutting a door opening through the basement wall and jack-hammering out the rubble. A sales engineer brought a layout plan for
the prefab forms that he had made from the floor plan I sent him. He climbed down into the pit and made the usual comment that he had never seen such a high pour against a dirt bank, and we went over his layout. Since his forms were, basically steel angle frames with inset plywood panels, they could not be cut. The entire form structure had to lock together like an erector set, each panel bolting through to the one beside or below it.

The pressure of a concrete pour increases with the height. I had three exterior walls 12" thick and two barrier walls 18" thick, all 8' tall, so there was heavy pressure, the greatest at the bottom, and a lot of concrete to lose if I had a blow out. Conventional wood forms depend, for their strength, on bolts or form ties that clamp one side to the other. Since I was forming only one side of the exterior walls, I had chosen this more expensive, steel-framed system.

I began forming the next weekend. I laid out 2x4's back of the form line and shot pins through them into the new slab. These would keep the form panels from blowing out at the bottom. I then began assembling the erector set, setting and plumbing panels, and bolting them together. The walls were formed by Sunday afternoon, and I called Sam, my superintendant, for a carpenter and a laborer the next day. On Monday, we built a system of wood posts and beams to shore up the roof-deck panels, then laid them out and bolted them to each other and to the intersecting wall panels. After more bracing inside what would be the shelter rooms, we had a form structure that I was confident would hold all the concrete pour pressures. Basically, the forms braced each other within each room.

The rebar sub sent an ironworker to install, tie, and brace the two mats of rebar - one over the other - that spanned across the roof deck, and to tie in the rebar bending out of the wall frame. An electrician followed setting conduit and boxes for the shelter's minimum light and power system. Sam came over Wednesday afternoon.

"Everything set for Friday?"
"Yeah. The City Inspector just signed it off. I've ordered the concrete and a pump."

Sam nodded and walked the planks lining the top of the bank. He peered down the darkened slots that would be the exterior walls.

"You've been lucky so far, but rain's predicted for next week."
"I know. Did you ever see such a forest of steel?"
"You're going to have trouble getting the vibrator into those roof mats."
"Can you be here? I'm still green when it comes to a pour like this."
"Yeah. We'd better put a man underneath pounding the panels with a hammer. That adds to the vibration. You don't want rock pockets."

The morning of the pour, we had three ready-mix trucks lined up, each scheduled to empty, return to the plant, and bring back additional loads. The pump operator was positioned on plank walkways over the rebar with his hose nozzle halfway down the wall form next to the house. The first truck's drum began to turn, the concrete poured into the pump's hopper, the hose started bouncing, and a steady flow moved out of the hose, spreading along the bottom. The operator moved the hose to keep the first level at two feet, and moved along the wall with the flow. Behind him came a laborer tamping with a rod, and another followed with the vibrator, stabbing its throbbing end down into the mix. I watched from the bank, feeling tension mount as the concrete flow rose in the walls. It rose the slowest in the 18" thick barrier walls. Finally, the walls were filled, and the flow was moving out over the roof deck, I could feel the tension draining out of me as the concrete moved like a lava flow over and around the deck rebar, gradually covering it and the deck-panel forms under. I could hear hammers below, banging the panels, and see the vibrator move from the walls to stabbing the deck concrete, Sam stood beside me.

"You're going to get good surfaces. The pump and the pea gravel were the answer. You'd have never got through that roof grid with one-inch rock. You may have a few rock pockets, but I doubt you'll have anything big."

The pumper finished and began cleaning up. The last concrete truck left, and two laborers began rodding the roof-deck slab to a plane.  Behind them another laborer was pounding the mix with a rock tamp to bring up a slurry for the finisher. Sam and I sat on what was left of my front porch with our beers.

"I'm going to coat the roof deck Sunday."
"How?"
"I'll pour a cold tar emulsion over it, lift the plastic off the bank, and fold it over the roof. When that sets, I'll pour another coating of emulsion over the plastic. That should wrap the whole shelter in a watertight envelope."
"Below the deck, the plastic is laminated to the concrete."
"Right."
"Might work. Below-grade waterproofing is always iffy, whatever you do. How is the water going to get out of the concrete?"
"Inside. Through the forms."
"It'll be slow. But you'll get a better cure. You could wind up with 5,000 pound concrete."

That night I had my first good night's sleep in two months.

The deck coating and overlayment went down as planned. and we had rain two days later. It was now into September - my Summer project had extended into Fall, mainly due to my treating so much of it as a do-it-yourself project - and the rain was the leading edge of a tropical storm from the Pacific. The storm lasted two days, and left a lake, nearly a foot deep, over the shelter roof deck. The three feet of remaining dirt banks, no longer covered by plastic, had sloughed down over the deck and were now sloped rather than vertical. Sam came by for payroll checks the next day.

"If you hadn't poured last Friday, you'd have mud walls now, a foot or two high."
"We'd be stripping forms and cleaning rebar."
"Starting all over and having to form the back side where the bank had sloughed off. In the rainy season. Only an ex-plasterer would take the chance you took. Or an ex-anything but carpenter."
"I told you when we started that I had some learning to do."
"Yeah, but you don't listen well. Okay, you came out smelling like a rose, but are you planning to build other shelters this way?"
"No, I've learned that lesson. We'll over-excavate, form both sides, waterproof the back side,  and backfill."
"Good, but it's going to cost more. You did pick the cheapest way, even if it was crazy."
"I know. I've already decided that the standard shelter can't be more than 10' by 10.' This one will make a good model, but we'd need a rich clientele to sell it into."

Sam opened another beer.
"I haven't been reading much about shelters lately."
"They haven't been in the headlines, and headlines are all I've had time to read. Who knows? Krushchev will probably cut off the water to West Berlin or we'll do something; they'll have another summit and yell at each other. Kennedy will come back and tell us all to build shelters again."
"So you've got a market that runs on panic."
"I don't like to put it that way, but that's about it."
"My wife told me there's going to be a story about shelters on TV."
"Yeah? What channel?"
"Whatever channel that carries Twilight Zone."

* * *

We didn't do much the next three weeks. I wanted the concrete to cure to its full strength before I pulled out the shores, stripped the forms, and brought back enough dirt to cover the top. Inside the shelter, there was a constant dripping of water out of the concrete, soaking the forms, and covering the floor slab with a wading pool. I did manage to dig a shaft next to the escape hatch, bolt on and seal the hatch-panel, then fill the shaft with sand. Whatever time I could spare from my construction business was spent in developing a smaller shelter plan, budgeting its cost, and establishing a sales price. Bystanders had, by now, decided that I was building a shelter, and several asked what one would cost to buy. They usually gasped when I replied.

"$13,000! That's more than I paid for my house! Just two years ago."
"My standard shelter is smaller - ten by ten - It's only $9,950."
"Only? What's in that thing, anyway?"

I explained that it was not just a fallout shelter; inside, you could survive the blast from a 25 megaton bomb three and a half miles away. For some reason, blast effect seemed to disturb them more than fallout. They had seen pictures of Hiroshima and from the Pacific atoll tests, all showing destroyed landscapes. They saw fallout ash as snow, radioactive at first but decaying by half-lifes in the weeks following a detonation. It bothered them when I reminded them that fallout was no danger to smashed corpses lying in crumpled-up fallout shelters. What was fallout but blast effect anyway, the remains of untold thousands of people, pets, toys, furniture, streets, windows, and whatever had been in the crater of the blast, floating down in undistinguishable flakes of ash? The usual answer was mumbled - you're probably right - I'll get back to you - followed by an unsteady walk to the car. I could see that I needed a more nuanced sales pitch.

I watched Shelter on Twilight Zone on a Friday night in late September, still waiting for the concrete to cure. I had come back tired from Sam's job on a stalled freeway, and I barely stayed awake through the episode. The panicked neighbors broke open the shelter door and swarmed in on the doctor-owner, thereby destroying the fallout protection, . Since they were too many for the shelter's air and water supply, they essentially destroyed his family's chance for survival because they hadn't provided for their own. Then the all-clear sounded, giving the virtuous doctor an opportunity to weigh in on the savagery imbedded in all of us. My reaction was scornful. They had torn down his sheet-metal shelter door by using a steel pipe for a battering ram, like opening a can. He had zero blast protection. If their home had been so far that the blast effect had only smashed in the door and not killed them, they would have been wide open to the fallout that would follow.  I would defy any mob to break through my door, braced to the top with solid timber.

However, the media idolized Twilight Zone and wasn't concerned about the door. Their articles and features had first promoted the idea of shelters, then derided the first, con-artist builders for their collapses, and now began to explore the morality issues raised by the Shelter episode. I decided to ignore their fevered imaginings and get on with more important business.

The curing time was past, and I pulled in a laborer to help me remove forms. We mopped out the last of the water, and began stripping the shoring, beams, and form panels. However, many of the form panels stuck to the deck underside after we stripped out all support. We had to crowbar them out and, being heavy, they hit the floor slab with loud clangs that brought my wife racing down to the basement entrance. To her, we looked like spectral images in the dust-filled, dimly lit interior, standing in a jumble of panels, posts, and beams, like a scene from Dante's Inferno. I realized, after stripping was done, why so many panels had stuck. We had massaged that concrete pour to the extent that it had partially glued to them. We had no rock pockets and no cracks, and we wouldn't have to sack the stripped surfaces, a repair process common after most concrete pours.

The shelter was now fully accessable, and we brought in a certified welder for its vents.  I had picked up the necessary lengths of 6" diameter pipe, 3" pipe, and large-bend ells.  The engineer had specified schedule 80 steel pipe, and this meant pipe with 1/2" thick steel walls. Three of us had been needed to lift out and carry the 6" thick lengths. Because of their wall thickness, the pipes had been cut square at the plant, and we had to build a wood shoring system to hold them in exact alignment. The welder had been recommended to me as expert, and his welds reflected his ability. I was getting continued reminders that a blast shelter was like a chain in every one of its aspects - as good as its weakest link. The pipes would have to stand as trees against any blast.

I had cast pipe sleeves into my  deck slab before the concrete pour, and he welded a seven foot extension standing up from each sleeve. Then he welded double bends - two welded ells - to the tops so that air could enter from the down-turn end while fallout particles would drop past to the ground. I had wondered why the suction from a hand pump pulling in air would not pull in the light, radioactive ash as well, but I never went beyond wonder. I planned to sell these shelters, not live in one. The two 6" pipes served as main intake and exhaust vents. One of the 3" pipes would serve for toilet exhaust and the other was tied in to a bacteriological filter to serve as an alternate intake. Another of the extra goodies I would sell - "You're concerned about poison gas or germ attack? Buy this filter system - you just screw the cap on the free-air pipe inside and screw the pump hose to the filter pipe."

After the pipework, I called the dirt broker for my dirt return and Al, my earthwork-equipment supplier, for a track loader.

"Don't send that last guy. He's afraid of a cave-in, which isn't going to happen."
"I know. We've heard that before."
"You want to see the plans? I've even got pictures of the steel in this thing."
"No, you and Sam know what you're doing, but some of my guys have had hairy experiences. I'll send Wild Bill, he'll try anything."

We brought in 6 dump truck loads, and Wild Bill circled the pit, grading the dirt and compacting it. When the last load arrived, I told the driver to back his truck over the shelter, before he dumped. Bill's loader was already over it, and he squinted at me.

"Aren't you overdoing it? You trying to prove something?"
"I'm going to take pictures. They'll be in my sales brochures, along with your smiling face. You'll be famous."

I took several pictures, then told them to wait, I was going to go down and check for any cracks or signs of deflection. That was too much for even Wild Bill.

"Are you crazy? What if this thing does go?"
"Hey, do you have problems standing under a concrete bridge when trucks drive over?"

I went down and satisfied myself that I really had built a bridge. We dumped the last load of dirt, Bill finished the grade, and the shelter was essentially completed.

I could now turn my full attention to sales and advertising.


Jack Eiden

2 comments:

  1. I wonder how many fallout shelters from that era still remain throughout the country. It doesn't seem to be a topic on many people's minds anymore.

    I remember that Twilight Zone episode.

    Lee
    Tossing It Out

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  2. If they were built like mine, they're still down there. Too many people remembered that episode. Thanks for the comment

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