A favorite McLean shortcut into Washington closes Saturday.

Old Chesterbrook Road in the vicinity of the bridge  over Pimmit Run will close to traffic on Saturday and will re-open by Tuesday, September 4.

VDOT is building the emergency replacement of  the bridge. The project will replace the worn timber decking and steel beams with a more durable concrete superstructure.

Old Chesterbrook Road is a favorite shortcut for McLean residents (and taxi drivers) to get into Washington, D.C. or to Reagan National Airport.

The new bridge will have two lanes of traffic and a sidewalk, and edge-to-edge it will be a few feet wider. The road alignment and elevation will be slightly improved to match the bridge, according to the Virginia Department of Transportation.

Detour- Via Westmoreland Street, Chain Bridge Road, Old Dominion Drive and Birch Road.See maps.

After the bridge re-opens in September, some additional daytime lane closures may be needed to finish detail work. The entire project is expected to cost about $1 million and be complete in November 2012. For more details.

The existing bridge was built in 1978 and has been structurally deficient for several years, VDOT said.