Outer Drive Bridge

Outer Drive Bridge
Outer Drive Bridge

The double-decker Outer Drive Bridge across the Chicago River
Carries Motor vehicles, pedestrians
Crosses Chicago River
Locale Chicago
Design Double-leaf, double-deck, fixed counterweight, trunnion bascule bridge
Coordinates 41°53′18.3″N 87°36′50.6″W / 41.888417°N 87.614056°W / 41.888417; -87.614056Coordinates: 41°53′18.3″N 87°36′50.6″W / 41.888417°N 87.614056°W / 41.888417; -87.614056

The Outer Drive Bridge, also known as the Link Bridge was started in 1929 and completed in 1937 as part of Ickes’s Public Works Administration in Chicago. It was planned by the Chicago Plan Commission, using Hugh E. Young as the consulting engineer, was designed by the Strauss Engineering Company, built by the American Bridge Company, and erected by Ketler and Elliot Company.



The building of this bridge was meant to create many jobs for Chicagoans and ease traffic flow on Michigan Ave and in the Loop. The Outer Drive Bridge runs along the shore of Lake Michigan from the far South Side of the city to the Loop, across the Chicago River, and connects the south to the north side of the city. In 1937 it was the longest, widest, and heaviest bascule bridge in the world.


While the completion of the Outer Drive was considered one of the most important projects in the PWA it took many years to complete. A main issue was funding. Due to a lack of provided security by Chicago Park Districts, the allotment for the bridge was revoked until the districts were all in position to comply. The total cost of the Outer Drive is estimated at $11,563,000.

Economic Justification

Calculations based on a traffic flow of 40,000 vehicles per day on a saving of eight minutes between Oak St. and Seventh St., made possible by the use of the bridge rather than Michigan Ave and on a delay cost estimated to be one cent per car per minute show that the saving in vehicle operation should amount to $584,000 per annum, which, capitalized at 5% would indicate that $23,360,000 could properly be spent to eliminate this delay. This shows that the Outer Drive bridge project is economically reasonable, showing a possible saving of $11,797,000.

Bridge Operation

According to Engineering News-Record “Each leaf is to be operated by two sets of gear trains, consisting of four sets of gear reductions. Each gear train is connected to two 100-hp. main operating motors, only one of which is to be used at a time. The time required for opening or closing the bridge against a 28-m.p.h. wind is stated to be 57.6 sec, of which 10 sec. is for acceleration and 2.86 sec. for deceleration. The main operating racks are bolted to the underside of the outside trusses, the pitch radius being 20 ft. The operating pinion, with a pitch diameter of 40 in, is mounted on a shaft of the gear train.

Heavy locking devices are provided at the center of the bridge and at the rigid in its closed position. The center lock in addition to holding the leaves together in their closed position, also transmits live load shear from one leaf to the other. This center lock consists of a set of four female castings bolted to the river end of one leaf, and a second set of four male units bolted to the river end of the other leaf, all castings being on the centerlines of the trusses. The male unit consists of two castings forming a toggle.

Heel or rear locks are necessary to prevent the leaves from opening when live loads pass over the part of the bridge between the trunnions and the rear break in the floor. Each leaf is provided with two pairs of rear locks, each pair being placed between the inside and outside trusses. The four locks of a leaf are connected by shafting, and operation by means of two 15-hp. motors set either side of the centerline of the bridge” (April 22, 1937).


External links

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Outer Drive East — General information Type Residential condos Location 400 E Randolph St …   Wikipedia

  • Bridge and tunnel — (often abbreviated B T) is a disparaging neologism for people who travel to Manhattan from surrounding communities.DefinitionThe term applies to those who visit from elsewhere in the New York Metropolitan Area, especially from New Jersey and Long …   Wikipedia

  • Outer Ring Road System — The Outer Ring Road System is coloured red in this map. The Outer Ring Road System, or more commonly known as ORRS, is a network of major arterial roads in Singapore that forms a ring along the towns outside the city. The ORRS is a semi… …   Wikipedia

  • Outer barrier — The outer barrier, also known as the Long Island and New York City barrier islands, refers to the string of barrier islands that divide the lagoons south of Long Island from the Atlantic Ocean. These islands include Coney Island, Long Beach… …   Wikipedia

  • Outer Banks — North Carolina s Outer Banks separating the Atlantic Ocean (east) from Albemarle Sound (north) and Pamlico Sound (south). Orbital photo courtesy NASA. The Outer Banks (also known as OBX) is a 200 mile (320 km) long string of narrow barrier… …   Wikipedia

  • Outer Harbor railway line — Outer Harbor Line Railways in Adelaide Trams in Adelaide …   Wikipedia

  • Outer Metropolitan Ring Road — The Outer Metropolitan Ring Road is a proposed freeway in Melbourne, Australia connecting the Hume Freeway at Kalkallo north of Melbourne, to the Princes Freeway south west of Werribee. The concept was announced as part of the Victorian Transport …   Wikipedia

  • Outer Hebrides — Eilean Siar and Western Isles redirect here. The term Na h Eileanan Siar (Western Isles), which redirects here, can also refer to the whole of the Hebrides. For the Scottish Parliament constituency, see Western Isles (Scottish Parliament… …   Wikipedia

  • Lake Shore Drive — Infobox road highway name = Lake Shore Drive marker alternate name = length mi = 15.83 length round = 2 length ref = cite web |author=Illinois Technology Transfer Center |url=http://www.dot.state.il.us/gist2/select.html |title=T2 GIS Data… …   Wikipedia

  • BP Pedestrian Bridge — Infobox Bridge bridge name = BP Pedestrian Bridge caption = The BP Bridge viewed from The Buckingham in Lakeshore East (2008 06 12) official name = carries = Pedestrians crosses = Columbus Drive locale = city state|Chicago|Illinois (Cook County)… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”