The busy 10600 South interchange on Interstate 15 is closing for 16 days to allow a relatively quick installation of a new underpass that crews will slide into place.

The Utah Department of Transportation plans to close most of the interchange beginning Friday at 9 p.m., and it will not reopen until Sept. 25 at 5 a.m.

10600 South will be closed in both directions over I-15. Drivers will still be able to exit from southbound I-15 onto westbound 10600 South, and will be able to take eastbound 10600 South onto southbound I-15 — but all other ramps will be closed.

UDOT recommends using 9000 South and 11400 South as alternate routes to cross I-15 or to enter or exit the freeway.

During the closure, UDOT says more than 10,000 man-hours of work are scheduled — with crews on site 24 hours a day — to install a new underpass that will connect the northbound I-15 off-ramp with Monroe Street to allow drivers to directly access South Town mall while avoiding traffic signals.

Next Tuesday, crews are scheduled to slide a prebuilt, three-sided underpass into place over six hours — the first time in Utah that a three-sided bridge will be slid into place.

(Rick Egan | The Salt Lake Tribune) A pre-constructed underpass for 106th south. UDOT will close 106th South interchange for 3 weeks for work to slide the new underpass into place. Thursday, September 7, 2017.

Once the underpass is placed, crews will work around the clock to fill in dirt around it, pave over the top of it to connect to 10600 South; and repair pavement on the 10600 South bridge over I-15.

When that work is completed, the interchange will reopen. However, the underpass will not open to drivers until next year. Crews still need to pave the bottom of the underpass and build a connection to the northbound I-15 off-ramp.

UDOT, working with Sandy and local businesses ”determined that a shorter full closure would be much easier on everyone rather than several months of lane closures and extra delays,” said Lisa Zundell, project manager.

Once the underpass opens, UDOT expects it handle about 4,800 cars per day — providing easier access to downtown Sandy and reducing traffic delays and congestions on 10600 South.

UDOT released some statistics about the project:

• The underpass is 183 feet long, about as long as the Leaning Tower of Pisa is tall.

• It is 40 feet wide, twice as wide as the Lincoln Tunnel in New York City.

• It is 22 feet high, tall enough for a double-decker London bus (15 feet high), with several feet to spare.

• It weighs 3 million pounds, equivalent to about 750 cars.

• It will slide about 150 feet in six hours, for an average speed of 25 feet per hour.