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New Piers

Launch Slideshow

Rebuilding a Church

Extending the piers

Rebuilding a Church

Extending the piers

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    The rebar for new grade beams and pier extensions was epoxied to the original piers.

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    Formwork for the pier extensions stopped a foot shy of the raised building to allow for setting the anchor bolt-studded cap plates and pumping the concrete.

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    Diagonal steel rods provide lateral bracing for the exposed portions of the piers; note the cold joint at the base of each pier between the old pier and the pier extensions.

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    Steel brackets welded to the cap plates anchor the transept framing to the foundation.

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    Cantilevered steel plates (left) welded to the cap plates and existing steel framing brackets in the original floor system provide support for the glulam rim joists (right) that support the new SIP walls.

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    With the glulam rims secured to the original structure and the new transept floor framing completed, the building is ready for wall A and roof panels.

While the lift was quick, we had to wait two months for the foundation contractor to complete the iron and concrete work needed to build the new pier foundation. Needless to say, I was anxious to get the building bolted down before the next storm season started. The shoring company reinforced the existing piers with grade beams and extended them with new rebar dowelled and epoxied into the old concrete (see slideshow). The crew also built new concrete piers for the two transept additions to the main building.

Steel work. To anchor the building to the piers, workers embedded 1/2-inch-thick steel plates into the concrete at the top of each pier during the pour. Each plate had four 3/4-inch by 12-inch J-bolts welded to it to strengthen the connection between the concrete and the steel.

We also bored holes through the forms and inserted short lengths of conduit so that later we could through-bolt steel brackets to the piers. These brackets accommodate 1-1/8-inch-diameter diagonal steel rods and steel tubing that reinforce the tall piers (see drawing "Pier Connection Details" on page 4 of the PDF).

Around the perimeter of the building, ironsmith Craig Campbell welded 1/2-inch-thick steel plates to the steel framing brackets that the shoring company had cut loose from the old piers. These new plates extend out over the tops of the piers 5 inches from the original wall plane, and help support the 5-inch by 15-inch glulams that hold up the SIP walls.

A few days after the pour, we measured the strength of the new concrete. It registered at over 3,000 psi, which meant the building could finally be lowered onto the piers. Campbell then spent a couple more days welding all of the metal plates together, using shims as necessary. He also cut bolt holes in the plates, and we sprayed the steelwork with Rust-Oleum’s Cold Galvanizing Compound (800/323-3584, rusto leum.com) to protect against corrosion.

Then we bolted the big perimeter glulams to the steel plates with 1-inch all-thread rod and to the framework of the church with 3/4-inch bolts 16 inches on-center. To account for the thickness of the panels’ inner OSB skins, we shimmed the glulams out from the framing with 5/8-inch plywood shims.