Ambassador Bridge
Coordinates: 42 ° 18 '43 " N , 83 ° 4' 27" W.
| Ambassador Bridge | ||
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| use | Road bridge | |
| Crossing of | Detroit River | |
| place | Detroit and Windsor, Ontario | |
| construction | Suspension bridge | |
| Longest span | 564 m | |
| Clear height | 46.33 m | |
| start of building | 1929 | |
| completion | 1931 | |
| planner | McClintic-Marshall Co. , Leon Moisseiff | |
| location | ||
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The Ambassador Bridge is a suspension bridge over the Detroit River that connects Detroit in the United States with Windsor, Ontario in Canada.
description
The four-lane road bridge is the busiest border crossing between the United States and Canada. There are large border control stations at both ends . Over 25% of the exchange of goods between the USA and Canada is carried over this bridge. The only other ways to cross the Detroit River are through the two-lane Detroit-Windsor Tunnel and the Michigan Central Railway Tunnel . There is also a ferry that only transports trucks and is intended for the transport of dangerous goods that are not permitted on the bridge or in the tunnel. The next road connection between the USA and Canada is the Blue Water Bridge, around 100 km further north, between Port Huron (Michigan) and Sarnia .
With a span of 564 m, the suspension bridge was the bridge with the largest span in the world when it opened on November 15, 1929, until it was replaced by the George Washington Bridge in 1931 . The bridge deck between the slender pylons , stiffened by diagonal struts, hangs on the two carrying cables and the vertical hangers attached to them. The lanes between the pylons and the huge structures for the rope anchors are on independent bridges that rest on narrow steel supports. In order to get to the clearance height of 46.33 m, there are also long ramp bridges on both sides. The name of the bridge is written in large letters on the 118 m high pylons. The letters are lit up at night; Fairy lights are attached to the suspension ropes.
The name of the Ambassador Bridge is based on an idea by its initiator Joseph A. Bower , who saw it as an ambassador between the two countries.
The toll-based Ambassador Bridge is owned by the Detroit International Bridge Company and its Canadian subsidiary The Canadian Transit Company via a company of the same name . These companies are controlled by entrepreneur Manuel J. "Matty" Moroun , who lives in the neighboring town of Grosse Pointe, Michigan and is counted among the richest Americans by Forbes Magazine .
Technical details
With a span of 564 m (1850 ft), the Ambassador Bridge has comparatively low lattice girders for stiffening on both sides of the carriageway , which, contrary to what was customary until then, had no cross struts above the carriageway. This makes it an early example of a suspension bridge that was influenced by Leon Moisseiff and constructed according to the deflection theory he developed further .
Its four-lane carriageway is 14.3 m (47 ft) wide; on the western side it has a 2.4 m (8 ft) wide sidewalk, which has been closed to traffic for a long time. Its clear height of 46.33 m (152 ft) is around 5 m higher than the traditional 135 ft that have been in place since the Brooklyn Bridge in New York. The slender pylons , stiffened by diagonal struts, are 118 m (386 ft) high and stand on concrete foundations that extend to the rocky ground 35 m (115 ft) below the surface. Only the middle section of the bridge is suspended from the suspension cables. The fields between the pylons and the anchor blocks are independent bridges with significantly higher trussed girders that rest on narrow trussed supports. However, they are not the same length. The bridge on the US side is 297 m (973 ft) long and that on the Canadian side is only 249 m (817 ft) long. The bridge structure between the anchors is 1109 m (3640 ft) long. This is followed by steel ramp bridges, with the ramp on the US side having a maximum gradient of 5% and being 436 m (1431 ft) long, while the ramp on the Canadian side has a maximum gradient of 3.25% and 734 m (2409 ft) long. Including the ramps, the bridge is around 2280 m long.
The suspension cables were manufactured using the air-jet spinning process from 7622 cold-drawn, galvanized wires, which were initially bundled in 37 strands with 206 wires each and combined in a hexagonal profile. Then they were pressed together by hydraulic rope presses to form a round cable and coated with corrosion protection. After the bridge deck had been installed and the resulting load on the cables with the bridge's own weight, insulating wire was wrapped around them as protection against corrosion. The anchors of the suspension cables were also lowered to the rocky ground. The structures for the anchors correspond to 16-story buildings, half of which are underground.
Second bridge project
Since around 2004 there have been projects for a second bridge, initially under the name Detroit River International Crossing (DRIC), later as New International Trade Crossing (NITC), which are to be built and operated by the public sector. The suggestions led to violent, also judicial disputes with Manuel "Matty" Moroun, who countered with the suggestion to build a second bridge himself. On April 12, 2013, the US State Department issued a presidential permit for the NITC. Further legal proceedings ended in February 2015 before the US Supreme Court , which allowed the construction of a second bridge.
This bridge is now called the International Bridge in memory of the famous ice hockey player Gordie Howe . It is to be built by the Windsor-Detroit Bridge Authority (WDBA) as a public-private partnership . In January 2016, three prequalified bidders were named. Construction is now expected to begin in 2019 at the earliest and completion in 2023.
To everyone's surprise, Matty Maroun received planning permission from the Canadian government in September 2017 for a new bridge to replace the Ambassador Bridge.
history
Project planning
Suggestions for a bridge have been made again and again since 1872, including by Gustav Lindenthal . Shortly after the First World War , Charles Evan Fowler developed plans for a suspension bridge with four railroad and two tram tracks, six vehicle lanes and two wide sidewalks. The plans led to the establishment of the Canadian Transit Company and the American Transit Company , which also received licenses to build the bridge from the Canadian Parliament and the American Congress, but the project failed. John W. Austin, a Detroit businessman who was pursuing the paint job for a future bridge and was one of its great proponents, approached CD Marshall, one of the owners of McClintic-Marshall Company , a prestigious Pittsburgh steel construction company , who helped him Introduced by Joseph A. Bower, a Detroit-born financier from New York . After reviewing various American and European bridge projects, Joseph A. Bower took over the two companies with the licenses in 1924, turned the American company into the Detroit International Bridge Company , appointed John W. Austin as head of finance and commissioned McClintic-Marshall with the planning and planning the construction of what was then the longest suspension bridge in the world. Despite the tunnel construction being pursued from another side, Bower arranged the financing of the project and was able to obtain the various approvals for the project, among others from the President of the United States, the Governor-General of Canada, the US Department of War, the Canadian Minister of Railways, the State of Michigan, the Province of Ontario, various shipping authorities, the affected Canadian community and its district administration and - after raising the planned (and customary since the Brooklyn Bridge in New York) clearance height from 41.15 m (135 ft) to 46 .33 m (152 ft) - also of the Detroit City Council. Only the Mayor of Detroit, John W. (Johnny) Smith, concerned about his re-election, vetoed the bridge, spoke out against the bridge and called for a referendum. After public discussions and various press campaigns, the population voted for the bridge with a large majority on June 28, 1927. Shortly thereafter, Smith also lost his re-election.
Construction phase
The construction work had started on May 7th, 1927 with a ceremonial first test drilling, otherwise the license for the bridge construction would have expired a few days later. On July 20, 1927, the final construction contract was signed, according to which McClintic-Marshall had to complete the bridge by August 16, 1930. In the event of a delay, the company would have had to pay the interest accruing during the period; in the event of early completion, it was entitled to half of the toll income.
The planning of the bridge came from McClintic-Marshall, who, as usual, was supported by a number of consulting engineers, including the structure of the suspension by Leon Moisseiff , who made a name for himself through the application of the deflection theory and the lighter constructions it made possible had made. He was responsible for the omission of cross struts above the roadway, a reduced height of the roadway girder and the use of steel alloys with silicon , which made the slender pylons possible.
Joseph A. Bower and the Detroit International Bridge Company as the client commissioned Ralph Modjeski to advise on all construction-related matters as well as construction supervision and technical acceptance.
The construction went smoothly at first. The four ropes for the catwalks were first lowered from boats to the bottom of the Detroit River and simultaneously pulled up to the pylon tops on August 8, 1928 in a short time. Joseph A. Bower turned this technically insignificant process into a large, media-effective event in which invited guests and 4,000 spectators celebrated the Lifting of the Cables . After completing the catwalks, he staged the First Public Crossing on September 15, 1928 , during which some courageous guests and press representatives were allowed to venture out on a catwalk.
The specifications stipulated the use of the usual cold-drawn wires for the suspension cables . In the meantime, heat-treated wires made of high- carbon steel had come on the market, which were supposed to be stronger and cheaper. These wires were already used in the construction of the Mount Hope Bridge , led by David B. Steinman , which was also built by McClintic-Marshall at the time. Further tests and a factory tour etc. a. by Modjeski and Moisseiff were positive, so that these wires were also used for the Ambassador Bridge for the production of the suspension cables, which took place between September 24 and December 27, 1928.
Due to the progress of construction, it was considered to open the bridge on July 14, 1929. At the end of February, however, there was information about broken wires at the Mount Hope Bridge, whereupon the construction manager of McClintic-Marshall stopped work on the Ambassador Bridge on March 1. Investigations of the ropes and Steinman's decision to replace the ropes on Mount Hope Bridge led to the decision to replace the ropes at the Ambassador Bridge at the end of March. This meant the dismantling of around 100 m of the bridge deck on both sides, the removal of the hangers, the piece-by-piece removal of the supporting cables and their anchors set in concrete - all activities for which there were neither models nor tried-and-tested work processes. Nevertheless, in mid-June 1929, the spinning of the new ropes started on newly laid catwalks, which were completed within two months.
On November 11, 1929, the opening ceremony took place as part of a large event with military parades, brass bands, speeches on both sides of the bridge and a total of around 150,000 spectators. Regular traffic over the bridge began on November 15, 1929 - still nine months before the contractually agreed completion date.
Operating time
About two months before the opening, the stock market crash in New York , which led to the Great Depression , which particularly affected the industry in Michigan. In 1930 1,600,000 vehicles had crossed the bridge, in 1934 the low point was reached with 586,730 vehicles. The bridge company made losses for years. In 1938 she had to apply for bankruptcy protection in the USA and Canada. The restructuring measures essentially consisted in converting the bonds issued by the bridge company, including the accrued interest claims, into shares in the company.
Despite all the financial difficulties, the bridge had always been properly operated and maintained.
After some initial improvement, the beginning of the Second World War brought new problems. Canada participated in it from the beginning and reduced border traffic. When the United States entered the war, gasoline was rationed there, but trucking traffic was less affected.
In 1945, more than 1 million vehicles drove over the bridge for the first time. Although the situation improved from then on, there were still problems: Canada introduced an austerity program in 1947 and later a ban on transferring Canadian dollars. The US Customs Service demanded payment for overtime worked on the bridge; the Detroit-Windsor tunnel continued to be serious competition; the depression of 1957-1960 left its mark, there were years of disputes with the US customs, who were not ready for 24-hour clearance and otherwise in no way cooperative, and the new Interstate 75 also led directly past the exit of the clearance area, without the bridge company ever talking about it.
The management of the bridge, which changed over the years, carried out numerous renovations and improved the arrival areas. The original black of the bridge was retained for a long time during the painting work, as the lighter colors quickly became unsightly due to the air pollution in Detroit. The access ramp on the US side was originally paved with large granite stones in order to achieve better adhesion. When the road surface was renewed, this granite pavement was removed; With the approval of Canadian customs, the community of Windsor received the paving stones to decorate parks and green spaces.
The current blue color was only introduced in the last few decades with a paint renovation. In 1981 the fairy lights were installed along the suspension cables. The name of the bridge on the pylons, on the other hand, dates back to the early years.
Change of ownership
Joseph A. Bower, the initiator of the bridge, and his family had control of the Detroit International Bridge Company and its Canadian subsidiary, The Canadian Transit Company , for decades . After his death in 1977, the Bower family also withdrew from the business. In 1979 the majority of the bridge company was acquired by the Central Cartage Company , a family company headed by Manuel J. Moroun.
literature
- Philip P. Mason: The Ambassador Bridge - a monument to progress. Wayne State University Press, Detroit, Michigan, 1987, ISBN 0-8143-1840-1
Individual evidence
- ↑ a b Ambassador Bridge Crossing Summary on the Federal Highway Administration website
- ^ MDOT - Michigan Department of Transportation
- ^ "I thought of the bridge as an ambassador between two countries, so that's what I called it. I want it to symbolize the visible expression of friendship of two peoples with like ideas and ideals. "(Quoted from Philip P. Mason: The Ambassador Bridge , p. 97)
- ↑ Manuel Moroun & family on forbes.com
- ↑ The technical details are based on Philip P. Mason: The Ambassador Bridge
- ↑ The proposed new US-Canada bridge: Guide to the controversy Detroit Free Press, July 12, 2012
- ↑ US grants permit to build 2nd Detroit-Canada bridge Detroit Free Press, April 12, 2013. On USA Today
- ^ Top US court rejects appeal in challenge to 2nd Detroit-Windsor bridge. February 23, 2015. On CTV News
- ^ Gordie Howe International Bridge on the WDBA website
- ↑ WDBA Announces Short-Listed Respondents for Gordie Howe International Bridge on the website of WDBA
- ↑ Gordie Howe bridge project faces another delay, pushing back completion to 2023. Article of August 22, 2017 in Windsor Star
- ↑ 7 things to know about Moroun's new Ambassador Bridge span. Article dated September 7, 2017 in the Detroit Free Press
- ↑ The information on the story is largely based on Philip P. Mason: The Ambassador Bridge
- ↑ Ambassador Bridge - History (PDF; 437 kB) on ambassadorbridge.com
- ^ A b Philip P. Mason: The Ambassador Bridge , p. 89 f
- ↑ Petition for relief according to section 77 (b) of the then National Bankruptcy Act of the USA
Web links
- Ambassador Bridge official website