MOVING DAY. Riggers used hydraulic dollies to move the 700-ton sub over 1,000 ft in April.

...risk is that something is going to crack or weaken," says M. Richard Klarich, field engineer for Jones Lang LaSalle, the owner’s Chicago-based program manager.

Klarich has directed construction at the museum since 1992 and compiled years of plans for the U-505 effort. "He has encyclopedic knowledge of the building," says Joel Asprooth, the owner’s vice president of finance and administration.

Led by Chicago-based general contractor W.E. O’Neil Construction Co., pavilion workers installednsteel sheeting and a jet-grout wall to keep the 8-ft-deep water table at bay. To the west, the slurry wall of an existing 1,500-car parking garage provides additional protection.

GOING DOWN. Jacks, timber move 4 in. at a time.

Under the building are 9-in.-dia micropiles driven 60-ft deep into hardpan and supplemented with 40-ft-deep, hand-dug underpinning piers. Above them spans two 40-ft-long, post-tensioned concrete beams that are anchored to the old load-bearing masonry walls.

In the main exhibit room, W.E. O’Neil built 34-ft-tall concrete walls that recline back 10°. Ready-mix was pumped in from the bottom up for smooth consolidation and finish. Wall sections have two-directional reinforcement, are 3-ft-thick and span 30 ft between pairs of concrete buttresses that bear on concrete footings.

The canted walls give the space a "bunker" look and also help support the soil around them, says David Black, project executive and Jones Lang LaSalle senior vice president. "We now are building around the sub," Black says.

UP FOR AIR. Klarich, Black lead the team.

Norsar Services Inc., Everett, Wash., handled U-505 this past April. Riggers moved the sub 1,000 ft to the pit with 18 self-propelled dollies. Workers lowered the sub, four inches at a time, using wood cribbing and hydraulic jacks.

Moments before the descent, the sub waited on skids near the pit. As planned, the cantilevered south wall withstood the 700-ton surcharge. "That was a scary moment," Kaye recalls. Asprooth says the move was pulled off "like a ballet."

(Photo top and center courtesy of the museum of science and industry/Scott Brownell; bottom by Tudor Hampton for ENR)