Bridge Description

On Sam White Lane over I-15 in the city of American Fork in Utah County, 30 miles south of Salt Lake City

Tier 1 (within 1 day)

ABC: overnight closure of I-15 (8 hrs); Conventional: Six additional full nighttime I-15 closures

Reduced onsite construction time; reduced traffic impacts; improved work-zone safety; improved site constructability; improved material quality and product durability

354-ft long and 76.8-ft wide two-span continuous steel plate-girder bridge (177 ft – 177 ft) roll-in; 48º skew; 1,910-ton self-weight

65800

Traffic management alternative, if constructed conventionally: would have impacted I-15 traffic (extended use of multiple lane closures)

The existing four-span bridge was 325 ft long and 34 ft wide with a minimum vertical clearance of 14 ft-7 inch. It was demolished in 2008 after being severely damaged by a collision.

The Sam White Bridge is the longest bridge in the US to be moved into its final location using self-propelled modular transporters (SPMTs). It crosses I-15 at a high skew and on a sharp vertical curve. The bridge has two 12-ft-wide traffic lanes in each direction, a 14-ft-wide turn lane, and a 12-ft-wide shoulder and 6-ft-wide sidewalk on each side. The 7-ft-deep cross-section consists of six steel plate girders at 13.5-ft spacing with 4.67-ft overhangs and a 10-inch-thick cast-in-place lightweight concrete deck. It has a 17.25-ft vertical clearance above I-15.

From August 2010 to March 2011, the bridge was built on the east side of I-15 approximately 500 ft from the bridge location. The abutments and interior support were constructed conventionally with concrete-filled pipe pile foundations. The interior support consists of six individual 4-ft-square cast-in-place concrete columns spaced at 20 ft. Each girder was set directly on a column. Each girder was connected to the column with an over-sized interlocking sole plate on a steel-reinforced elastomeric bearing pad; the connection accommodated setting tolerances during the bridge move as well as subsequent loading due to girder rotation and movements due to temperature and seismic effects. Saturday EveningOn March 26, I-15 was closed at 11 pm. At the bridge temporary location the two-span unit was lifted off the temporary supports on four lines of self-propelled modular transporters (SPMTs) (two lines per span), and moved 500 ft across eight lanes of I-15 to the final bridge location.Sunday MorningThe bridge was set in place at approximately 4 am. I-15 was re-opened at 7 am, three hours ahead of schedule. The abutments were made integral after the move, and a thin-bonded polymer overlay was placed.

Lightweight concrete deck, 70 ksi high performance steel (HPS) in girder flanges over the interior support