Steel 101 : An Enormous Erection

Sorry, I couldn't help myself on the title. As the basement took shape and the first layer of floor and walls were finished, it was time to start placing the new steel girders that would form the skeleton of the new/old building. This phase was like being a kid with a big erector set. I didn't actually have any role to play in the making or assembling of these parts but I was on hand to watch it go together and it was a cool process to witness.

The first giant I beams that were placed first were all verticals. Some 50' or slightly longer. Each base flange has holes pre-drilled that fit the pattern of the bolts that were previously buried in the cement foundation. When the foundation was poured, they used surveyor's tools to place these in the exact position they needed to be. Nonetheless, it was still amazing to watch these giant beams come floating in and line up perfectly with the bolts that had been cemented into place 6 months before!

As the beams were being lifted off the truck and over the wall, the workers placed a stack of a dozen large steel washers on each upright bolt or a layer of tin squares(shims) under the flange. When the I beam flange slides onto the bolts, it compresses the steel washers/shims slightly. They then add washers and bolts to the top side of the flange, and using a large pneumatic torque driver, they cinch the bolts down while carefully watching a plumb level. The washers act as a compressible spacer so that correctly torquing the bolts into place, locks the I beam perfectly plumb. The footer for the I beam is sunk into the basement floor about 12 inches. After they have the steel in place, welded and bolted to all the other adjacent pieces of steel. The general contractor and the steelworkers confirm that the structure is correctly bolted into place and squared up using modern technology, they start welding all the joints and add-on structures to the heavy duty frame itself. That old building is as strong as any modern one, possibly more so because of the very thing brick walls. All the holes in the basement floor where the verticals were bolted down get filled with high pressure concrete. Encasing the flange and the base of the vertical I beam and leaving a very smooth finish around the steel. The entire design involved concrete floors that were treated with and acid wash for color and was otherwise smooth and easily cleanable. There was a very utilitarian mindset in the fundamentals of the new design. 800 drunk and rowdy college kids can be kinda tough on a building. Multiply that times 250 nights a year and you get the idea. The new Georgia Theatre was going to be nice, but it was also going to be a lot harder to break things as well as a lot easier to clean!

During the design phase, each member and piece of steel is assigned a number. This seems obvious if you think about it. They need to know what piece goes where. No two pieces are exactly the same! Each load of steel that was delivered, had been loaded in a specific order, anticipating the correct sequence they would need to take them off and place them. It's really remarkable how precise this process has to be. All these steel parts and pieces are fabricated in a factory and then shipped to the job site. Some pieces and sub-structures have to be built, disassembled for transportation, and then reassembled on the job site before being installed.

All of the steel in the building is bolted, cemented, and welded into place. The real strength of the building comes from the fact that the entire structure is welded/bolted together, including the brick walls that were further strengthened by the concrete and rebar that spans the floors, and fills all the spaces and gaps in the cinderblock walls internally.

In the pictures below, the workers are placing the very first piece of new steel. This was a very exciting day for all of us. It felt like we were making great progress and we were! But it was fall 2010 and winter was just around the corner, with all the surprises a Georgia winter can bring.