Bridges of PittsburghBridges of Pittsburgh

By Jonathan SkonerBy Jonathan Skoner

FactFact

– By the 1930s Pittsburgh in the valleys By the 1930s Pittsburgh in the valleys and hills of Allegheny County in western and hills of Allegheny County in western Pa had more bridges than any Pa had more bridges than any comparable place in the world.comparable place in the world.

Why does Pittsburgh have so Why does Pittsburgh have so many Bridges?many Bridges?

• Pennsylvania is really an ancient Pennsylvania is really an ancient plateauplateau

• It was carved away over hundreds It was carved away over hundreds and thousands of years by rivers that and thousands of years by rivers that were searching their way to the Gulf were searching their way to the Gulf of Mexicoof Mexico

Prime LocationPrime Location

• Because of the Mountains and the Because of the Mountains and the headwater of the Ohio River -- headwater of the Ohio River -- Pittsburgh was able to ship timber, Pittsburgh was able to ship timber, oil, coal, glass, iron, and steel to oil, coal, glass, iron, and steel to almost anywherealmost anywhere

• Because of Pittsburgh’s growth the Because of Pittsburgh’s growth the city became well known in Americacity became well known in America

• All over America - states, cities, and All over America - states, cities, and companies turned to Pittsburgh for companies turned to Pittsburgh for things neededthings needed

• Because of Pittsburgh’s growing industry, Because of Pittsburgh’s growing industry, Pittsburgh was able to supply America with Pittsburgh was able to supply America with steel to build thingssteel to build things

• Some things that contain Pittsburgh steel Some things that contain Pittsburgh steel are the Brooklyn Bridge, the Washington are the Brooklyn Bridge, the Washington Monument, the Eads Bridge crossing the Monument, the Eads Bridge crossing the Mississippi at St. Louis, the first Mississippi at St. Louis, the first skyscrapers in Chicago and New York, and skyscrapers in Chicago and New York, and in the railroads crisscrossing the American in the railroads crisscrossing the American WestWest

• During the various wars of the During the various wars of the country Pittsburgh quickly supplied country Pittsburgh quickly supplied the military with and endless supply the military with and endless supply of war materials all over the world. of war materials all over the world. Some of these products were -- Some of these products were -- cannons and cannon ballscannons and cannon balls

• After the 1850s railroads began to After the 1850s railroads began to appear in Pittsburghappear in Pittsburgh

• With the combination of railroads, With the combination of railroads, mountains, and bridges Pittsburgh mountains, and bridges Pittsburgh became the busiest industrial state in became the busiest industrial state in AmericaAmerica

• Because of Pittsburgh’s effort in bridge Because of Pittsburgh’s effort in bridge production Pittsburgh was recognized by production Pittsburgh was recognized by many famous companies for designing and many famous companies for designing and building bridgesbuilding bridges

• Between 1924 and 1932 Allegheny County Between 1924 and 1932 Allegheny County built 99 bridgesbuilt 99 bridges

• Also, Bridge Engineers were attracted to Also, Bridge Engineers were attracted to Pittsburgh from all over the world because Pittsburgh from all over the world because of the challenging terrain of Pittsburghof the challenging terrain of Pittsburgh

ChallengesChallenges

• Some challenges that engineers were presented with were – Some challenges that engineers were presented with were –

• Getting the first rope across the river to begin building Getting the first rope across the river to begin building

• In the older days a row boat was sometimes used or even shooting it across with a bow and arrow

• Today helicopters and cranes are used

• Another challenge was getting a strong foundation for bridges. When bridges were being built columns and piers were used as supports. The supports had to be dug down deep enough into the ground so that they had firm footing such as an underlying strata of rock, sand, or satisfactory soil

• Today Hollow cylinders are dropped into rivers and hydraulic pumps were used to dewater an excavation allowing workers to dig even deeper

AmbridgeAmbridge

• What was it named after?What was it named after?

•American Bridge CompanyAmerican Bridge Company

American Bridge CompanyAmerican Bridge Company

• Formed in the 1900s by the same interests that controlled the United States Steel Corporation Formed in the 1900s by the same interests that controlled the United States Steel Corporation • Was an attempt to monopolize the nation's bridge-building industry Was an attempt to monopolize the nation's bridge-building industry • Within years after its founding American Bridge Company was able to claim over half the structural-steel Within years after its founding American Bridge Company was able to claim over half the structural-steel

fabricating capacity of the countryfabricating capacity of the country• In its early years it depended on affiliated firms to erect its bridgesIn its early years it depended on affiliated firms to erect its bridges• After the 1920s the company was able to build bridges on its own without any assistanceAfter the 1920s the company was able to build bridges on its own without any assistance• After 1904 their company headquarters were located in PittsburghAfter 1904 their company headquarters were located in Pittsburgh• Now they have headquarters in: Bristol, TNNow they have headquarters in: Bristol, TN

Chicago, ILChicago, IL Coraopolis, PACoraopolis, PA Long Beach, CALong Beach, CA New York, NYNew York, NY Orlando, FLOrlando, FL Reedsport, ORReedsport, OR Tampa, FLTampa, FL Williamsburg, VAWilliamsburg, VA

“ “Although never in complete control of the bridge market, the American Bridge Although never in complete control of the bridge market, the American Bridge Company supplied a substantial portion of the steel bridges purchased by state Company supplied a substantial portion of the steel bridges purchased by state and local highway officials in the early 20th century, and there can be no doubt and local highway officials in the early 20th century, and there can be no doubt that the company was the single most important fabricator of the that the company was the single most important fabricator of the period.”(Notable Bridge Designers and Builders of Connecticut, Builders)period.”(Notable Bridge Designers and Builders of Connecticut, Builders)

IronIron

•The first iron was used in bridges in the late 18th century. One of the first iron bridges was built in Brownsville East of Pittsburgh

• John Roebling

• Inventor of iron rope/cable in the 1840s for the Pennsylvania Canal which crossed the Allegheny Mountains to reach Pittsburgh

• Roebling had figured out how to spin and wine wire into a tight rope

• The wire rope changed the technology of the suspension bridges forever

• The strength of the iron rope was much stronger that the fiber rope previously used and therefore led to the building long suspension bridges

• In the 1870s steel replaced the wire rope and made even more possible for longer bridges to be built.

AluminumAluminum

• Strong and Lightweight material that started to be used in the 1930s.

• Aluminum was important because it decreased the weight of bridges that were built

• In 1934 the Smithfield St. bridge was one of the first Bridges to use Aluminum--- It replaced its old wrought iron floor supports and installed new aluminum decking

COMPUTER-ASSISTED DESIGN (CAD)

•During the late 1960s CAD made it possible for bridge engineers to make electronic models of bridge designs

•The computer greatly influenced the building of bridges - The high speed analyzing of the computer was saved a lot of time when designing of bridges

The Fort Pitt and Fort Duquesne bridges were among the first bridges to ever be built with Computers

Bridge EngineersBridge Engineers

• John Roebling (1806 – 1869)John Roebling (1806 – 1869)

• The greatest bridge engineer of the 19The greatest bridge engineer of the 19thth century century• Famous for the Brooklyn BridgeFamous for the Brooklyn Bridge• Started his career in PittsburghStarted his career in Pittsburgh• It is believed that he got his thoughts on the wire rope after watching the It is believed that he got his thoughts on the wire rope after watching the

building of the Pennsylvania Canal. He saw many men die while they building of the Pennsylvania Canal. He saw many men die while they worked because of the rope they were using broke.worked because of the rope they were using broke.

• Roebling’s first success was in building a replacement bridge for the old Roebling’s first success was in building a replacement bridge for the old canal bridge that crossed the Allegheny River at Eleventh Streetcanal bridge that crossed the Allegheny River at Eleventh Street

• He finished the bridge in 1844 after only a stunning 6 month constructionHe finished the bridge in 1844 after only a stunning 6 month construction• Other major bridges that he built with his wire rope were the second Other major bridges that he built with his wire rope were the second

Monongahela St. Bridge in 1846 and the suspension bridge at 6Monongahela St. Bridge in 1846 and the suspension bridge at 6thth street street• Best known for the Brooklyn Bridge in New York. However, he died during Best known for the Brooklyn Bridge in New York. However, he died during

the construction due to injury and his son finished building.the construction due to injury and his son finished building.

Bridge EngineersBridge Engineers

• Gustav Lindenthal (1850 – 1935)Gustav Lindenthal (1850 – 1935)

• Famous for the Simthfield St. BridgeFamous for the Simthfield St. Bridge

• A.K.A.A.K.A. “Dean of bridge engineers” “Dean of bridge engineers”

• The National Historic Landmark – Smithfield St. Bridge was his first major The National Historic Landmark – Smithfield St. Bridge was his first major bridgebridge

• The Smithfield St. Bridge of 1881 – 1883 is known today as the oldest steel The Smithfield St. Bridge of 1881 – 1883 is known today as the oldest steel bridge in the United Statesbridge in the United States

• Lindenthal’s second most famous bridge is the 7Lindenthal’s second most famous bridge is the 7thth St. Bridge of 1884 – 1927 St. Bridge of 1884 – 1927 where he used a double set of wire cableswhere he used a double set of wire cables

• Just as Roebling did Lindenthal moved on to larger and stronger bridgesJust as Roebling did Lindenthal moved on to larger and stronger bridges

• In 1907 he designed the Queensboro Bridge that crosses the East River in In 1907 he designed the Queensboro Bridge that crosses the East River in New York City New York City

Bridge EngineersBridge Engineers

• George Richardson (1896 – 1988)George Richardson (1896 – 1988)

• A key piece in Allegheny Bridge building from 1924 – 1937 – A large growth A key piece in Allegheny Bridge building from 1924 – 1937 – A large growth time for Alleghenytime for Allegheny

• A draftsman with American Bridge Company and later joined the county A draftsman with American Bridge Company and later joined the county works departmentworks department

• He helped on many of the major bridges in Pittsburgh by assisting in the He helped on many of the major bridges in Pittsburgh by assisting in the design of themdesign of them

• Some works of his were – McKees Rocks and West End Bridges, Some works of his were – McKees Rocks and West End Bridges, Westinghouse Memorial Bridge, Liberty Bridge, the second Point Bridge, Westinghouse Memorial Bridge, Liberty Bridge, the second Point Bridge, the South Tenth Street Bridge, and the Homestead High Level Bridgethe South Tenth Street Bridge, and the Homestead High Level Bridge

• Later started his own company called “Richardson, Gordon and Associates” Later started his own company called “Richardson, Gordon and Associates” which later became part of “HDR Engineering Inc.”which later became part of “HDR Engineering Inc.”

• Started trend of using acronyms as names of companiesStarted trend of using acronyms as names of companies

International Bridge Conference International Bridge Conference AwardsAwards

• The three awards given out each year The three awards given out each year at the conference are the:at the conference are the:

• George S. Richardson Medal – single recent, outstanding George S. Richardson Medal – single recent, outstanding achievmentachievment

• John A. Roebling Medal – lifetime achievement in bridge John A. Roebling Medal – lifetime achievement in bridge engineeringengineering

• Gustav Lindenthal Medal – a bridge with an aesthetic merit Gustav Lindenthal Medal – a bridge with an aesthetic merit component erected within the last 100 yearscomponent erected within the last 100 years

Underground BridgeUnderground Bridge

• Built in 1897 crossing the St. Pierre’s Built in 1897 crossing the St. Pierre’s Ravine to get people to the entrance of Ravine to get people to the entrance of the Carnegie Librarythe Carnegie Library

• In 1913 the ravine was filled and the In 1913 the ravine was filled and the bridge was covered because the city bridge was covered because the city wanted a parking area between the newly wanted a parking area between the newly built Forbes Field and the Carnegie Librarybuilt Forbes Field and the Carnegie Library

• The dirt and rocks that were used to fill The dirt and rocks that were used to fill the ravine was from the removal of the the ravine was from the removal of the hump on Grant Streethump on Grant Street

• The bridge is still thereThe bridge is still there

The First Smithfield St. Bridge The First Smithfield St. Bridge 1818 – 1845 (a.k.a. 1818 – 1845 (a.k.a. Monongahela St. Bridge)Monongahela St. Bridge)• Built in 1818Built in 1818

• Designed by Lewis WernwagDesigned by Lewis Wernwag

• The first bridge in the city of PittsburghThe first bridge in the city of Pittsburgh

• 1500 feet long and had 188 foot spans1500 feet long and had 188 foot spans

• Had tool booths at both ends of the bridgeHad tool booths at both ends of the bridge

• Covered bridgeCovered bridge

• Burned down in the Great fire in April of 1845Burned down in the Great fire in April of 1845

The Second Smithfield St. The Second Smithfield St. BridgeBridge1846 - 18431846 - 1843• Built in 1846 on the same piers of the earlier Smithfield St. Built in 1846 on the same piers of the earlier Smithfield St.

BridgeBridge

• Bridge engineer – John RoeblingBridge engineer – John Roebling

• Wire Cable Suspension BridgeWire Cable Suspension Bridge

• Took 7 months to buildTook 7 months to build

• Came down in 1883 when its replacement was openedCame down in 1883 when its replacement was opened

The Third Smithfield St. BridgeThe Third Smithfield St. Bridge1883 – Present Day1883 – Present Day

•Built from 1881 – 1883Built from 1881 – 1883•Built By Gustav Lindenthal who Built By Gustav Lindenthal who

also designed the Seventh St. also designed the Seventh St. Bridge (1884 – 1925)Bridge (1884 – 1925)

•One plaque that is on the South One plaque that is on the South Portal of the bridge: Portal of the bridge: PITTSBURGH PITTSBURGH OUTSTANDING ACHIEVEMENT AWARD 1994 - OUTSTANDING ACHIEVEMENT AWARD 1994 - SMITHFIELD SMITHFIELD STREET BRIDGE REHABILITATION PROJECT STREET BRIDGE REHABILITATION PROJECT

South Twenty-Second South Twenty-Second Street Bridge (Brady Street Street Bridge (Brady Street Bridge)Bridge)

• Built from 1895-96Built from 1895-96

• Built by the Schultz Bridge and Iron Co. of Built by the Schultz Bridge and Iron Co. of Pittsburgh Pittsburgh

• steel-riveted, through-highway bridge steel-riveted, through-highway bridge

• the second to be owned by the city and the first the second to be owned by the city and the first free bridge in Pittsburgh free bridge in Pittsburgh

Veterans Bridge Veterans Bridge

• Bridge Type: Steel, welded girder Bridge Type: Steel, welded girder

• Built from 1986 – 1987Built from 1986 – 1987

• Built by PennDotBuilt by PennDot

THREE SISTERS BRIDGESTHREE SISTERS BRIDGES

• Bridge Types: Self-anchored Suspension Bridge Types: Self-anchored Suspension bridgebridge

• Roberto Clemente BridgeRoberto Clemente Bridge• Built from 1925 – 1928Built from 1925 – 1928• Built by Allegheny CountyBuilt by Allegheny County• Seventh St. BridgeSeventh St. Bridge• Built from 1925 – 1926Built from 1925 – 1926• Built by Allegheny CountyBuilt by Allegheny County• Ninth St. BridgeNinth St. Bridge• Built From 1925 – 1928Built From 1925 – 1928• Built by Allegheny CountyBuilt by Allegheny County

• site conditions did not allow for typical site conditions did not allow for typical anchorages. anchorages.