Trinity Episcopal Church used to sit on short concrete piers, about 4 feet above grade and 14 feet above sea level in Pass Christian, Miss. But when Hurricane Katrina devastated the Gulf Coast in August 2005, the 26-foot-deep storm surge left Trinity under more than 12 feet of water — enough to wash away the walls and another two buildings on church grounds, and enough to destroy the middle school across the street. Somehow, the building’s floor system, laminated arch framework, and roof survived virtually intact.
After the storm, an engineer who checked out the building feared that the frame had been too badly racked to be repaired, and he recommended that the church be demolished. But members of the church’s building committee weren’t so sure and asked my company to take a closer look. It was true that all but one of the arches were out of plumb, but my laser measurements showed they were off by different distances — from 1/2 inch to 1-1/4 inches in 16 feet — and in different directions. After inspecting the timbers and the connections, we concluded that the frame had already been out of plumb after being rebuilt following Hurricane Camille in 1969, but that it was still structurally sound.
The congregation wanted to salvage as much of the church as possible, and the decision was made to rebuild again around the existing arch frame. To make the church more hurricane-resistant and to qualify for LEED certification, project architect Leah McBride specified SIPs for the walls and roof. And to meet local codes and FEMA’s new base-flood elevation (BFE) recommendations — and thereby qualify for significantly lower insurance rates — we would raise the church another 10 feet above its former elevation, to 14 feet above ground level. That would put the finish floor of the new church about a foot above the area’s new 23-foot BFE. My company was hired to be the general contractor for the project.
Lifting the Building
Before lifting the building, we used plywood gussets to repair a number of floor joists; they had cracked lengthwise where they’d been improperly notched to fit the steel brackets tying the floor system to the original foundation. We also replaced some termite-damaged lumber, then resheathed the entire floor with 3/4-inch Edge Gold T&G panels (888/453-8358, ilevel.com).
Raising a 3,000-square-foot, 66-ton building more than 10 feet was a terrifying prospect, but I was reassured when I learned that the lifting contractor — Davie Shoring of New Orleans — had 150 other buildings in the air at the same time. It took the shoring crew only a couple of days to place the two 100-foot-long main steel I-beams and ten 30-foot-long cross beams, install cribbing for the hydraulic jacks, and break the building loose from the old foundation (see slideshow).
The actual lift took about 11 hours, spread out over the course of two days in May 2009. The 10 jacks were connected to a diesel-powered hydraulic pump, which raised them simultaneously at a rate of 10 seconds per 6-inch lift. Then the crew would take about an hour to install more cribbing, lower the building onto the new cribbing, reposition the jacks, and repeat the process. By the time the building reached its final position, movement over its 100-foot length was less than 3/8 inch, a virtually flat lift.