President, Ian Firth, continues his discussion of great structures celebrating anniversaries this year. This month, structures which are 60 years old in 2017.
So, after seven months we have now got down to structures which are roughly the same age as me! I'm not sure which is in better condition, but all of these structures are still in service and so am I, I'm glad to say! Mind you, I confidently expect all of these to outlast me thanks to the skill of the structural engineers involved in their creation.
As before, our structures this month come from all over the world – Ghana, Morocco, Italy, Germany and the USA – reflecting the wide dispersion of our members and the importance of structural engineering across the globe. Enjoy!
1. Adomi Bridge, Ghana
Of course we have to start with a bridge! This one spans the Volta River that drains into the Gulf of Guinea, south of the Akosombo Dam. Journey from the north of Ghana and one will have to go through the eastern corridor and finally use the Adomi Bridge. Accra, the capital of Ghana, is about 130km from Atimpoku and Tema is also 100km away.
It is a two-hinged steel truss-arch bridge with a main span of 245m and was completed in 1957 at a cost of a little under £0.7 million.
Wikipedia credits the design to Dr William Brown of Freeman Fox & Partners (although I doubt he did it on his own!) but the Ghanaweb web site mentions Halcrow, together with the contractors Dorman Long (who they call Norman Long!), so you never know. I suspect this was a case of concept design by Freeman Fox and detailed design by Halcrow for the contractor under a Design and Build contract. No doubt someone reading this will clarify for us.
Image: Wikimedia Commons, Nora Morgan
The bridge is a very important socio-economic and strategic link, opening up remote parts of Ghana to potential development and linking the central and northern parts of the Volta region with other parts of the country. It also provides access to Lome in neighbouring Togo to the east.
Before the bridge was constructed, a ferry at Senchi was the only mode of conveyance for goods, transport, and people in the region, which was dangerous and unreliable in more ways than one.
In 2014-2015, the bridge underwent substantial repair and upgrading works for about £10 million. All 23 sections of the bridge deck and over half of the suspender cables were replaced.
2 . Fedala Reservoir, Morocco
Image: Yoshito Isono, Structurae
This is a classic and beautiful example of a prestressed concrete shell structure by Eduardo Torroja. With a maximum diameter of 40m, the shell thickness varies from only 10 to 28cm, and the structure comprises a series of arched internal shells. I must admit that when I look at the section I reckon there must be a lot of hoop tendons to carry the bursting forces arising from the 3500m3
of water inside.
Eduardo Torroja (1891 – 1961) was one of the great Spanish engineers of his generation. Notable as a pioneer in the design of concrete shell structures, he graduated as an engineer in 1923 and initially worked with a contractor. He became a consulting engineer in 1927, and in 1934 he founded an experimental institute with José Maria Aguirre to develop new uses and theories for reinforced concrete.
Torroja's brilliant career was interrupted during the Spanish Civil War (1936 to 1939) during which some of his innovative structures were sadly destroyed. But we still see the influence of his work in thin-shell structures around the world today.
3. Palazzetto dello Sport (Little Sports Palace), Rome
From one great structural hero to another engineering genius – Pier Luigi Nervi – and his magnificent indoor sports stadium built for the 1960 Rome Olympic Games. This beautiful dome structure, also completed in 1957, has a span diameter of 61m and a rise of 21m, and it seats up to 5000 spectators.
Image: Wikimedia Commons, Mister No
The Palazzetto dello Sport was designed by architect Annibale Vitellozzi and its reinforced thin-shell concrete dome was engineered by Pier Luigi Nervi under the direction of Engineer Giacomo Maccagno. The venue hosted basketball, boxing and other sports during the 1960 Olympic Games.
The innovative ribbed reinforced concrete dome is formed from 1620 prefabricated concrete pieces, braced by concrete flying buttresses. Most of the structure was prefabricated, enabling the entire dome to be erected in 40 days. The lower half of the dome has a continuous ribbon of window the whole way around the circular stadium, beneath the elegantly ribbed, white-painted concrete ceiling, creating a really wonderful interior space.
Perimeter buttresses. Image: Wikimedia Commons, Blackcat
Interior roof detail. Image: Wikimedia Commons, Absurdicus
Pier Luigi Nervi was educated and practised as a "building engineer" in Italy. His artistic and elegant designs became famous all over the world and he was a much sought after engineering collaborator for many architects. He died in 1979.
4. House of the Cultures of the World, Berlin
From Italy, we move to Germany and this rather impressive arts venue in Berlin, previously known as the Kongresshalle and also known as the Benjamin Franklin Hall.
Image: Wikimedia Commons, Berthold Werner
The Haus der Kulturen der Welt (House of the Cultures of the World) is an arts venue, exhibition and cultural centre. Situated in the Tiergarten area, its varied all-year-round programme includes exhibitions, talks, lectures and seminars, concerts and festivals. John F. Kennedy spoke here during his famous June 1963 visit to West Berlin.
In 1957, an architecture exhibition, Interbau, brought international talent and new architectural visions to West Berlin. The Congress House, given as an American gift to West Berlin, was US architect Hugh Stubbins' contribution to the exhibition and was regarded as a technically revolutionary as well as creatively brilliant achievement. Its highly original parabolic roof was nicknamed – and known ever since - as the "Pregnant Oyster". Three levels accommodate a large reception hall, a cafeteria, a 400 seat theatre auditorium and additional rooms where seminars and talks take place. A huge auditorium seating 1250, has state-of-the art projection facilities and is a film screening venue during the International Film Festival Berlinale each February.
Image: Wikimedia Commons, Kernpanik
The roof is a pre-stressed concrete shell structure, and is supported at only two points. Sadly it has not enjoyed a happy life as it collapsed in May 1980 killing one person and injuring several others. I have not been able to find any details or explanations for the collapse, but it was re-built in the same form as before. I must say it looks uncomfortably unstable with only two supports, albeit fat ones. This is fine under symmetrical loading, but presumably they experience very large overturning moments otherwise.
5. Kingston – Rhinecliff Bridge, New York, USA
The Kingston–Rhinecliff Bridge or George Clinton Memorial Bridge is a steel truss bridge that carries the NY 199 highway across the Hudson River in New York State north of the City of Kingston and the hamlet of Rhinecliff. It was opened to traffic on February 2, 1957 and was built at a cost of $17.5 million. It has a total length of 2375m, with two main spans of 244m, one on each side of the river, providing a navigation clearance of 46m. It was designed by David Steinman and carries two lanes of traffic and approximately 17,000 vehicles per day.
Plans for building a bridge here to replace the unreliable and sporadic ferry service began in the early 1940's. A crossing was much needed as there were no other bridges over the Hudson for quite some distance in either direction. The site for the bridge was originally intended to be between Kingston Point and downtown Rhinebeck, and the design was initially for a suspension bridge. However, it became necessary to relocate the crossing about three miles to the north where ground conditions were unsuitable for a suspension bridge, so Steinman opted for the truss bridge instead.
Image: Wikimedia Commons, David Hermeyer & Samuel Wantman.
The Kingston-Rhinecliff Bridge celebrated its 50th anniversary in 2007 as the bridge has received new decking, deck reinforcement and continuous improvements for safety and reliability. In 2000, the bridge was renamed the George Clinton Kingston-Rhinecliff Bridge in honour of Clinton who served as the longest serving Governor of New York State (1777-1795, 1801-1804) and as Vice-President of the United States under both President’s Thomas Jefferson and James Madison.
6. Walt Whitman Bridge, Philadelphia, USA
The Walt Whitman Bridge is a single-level suspension bridge with a classic steel truss deck typical of most American suspension bridges (it pre-dates the first streamlined box girder at Severn Bridge by nine years), and carries Interstate 76 highway over the Delaware River from Philadelphia to Gloucester City, in Camden County, New Jersey. It has a main span of 610m, a total length of 998m, and provides a navigation clearance of 46.5m over the river. Construction began in 1953 and it opened to traffic on May 16, 1957.
The bridge carries seven lanes of traffic, three in each direction and a centre lane that carries peak tidal flow through the use of a "zipper" barrier installed on the bridge in 2000. This barrier is hinged every metre and can be shifted automatically by a machine that drives over the bridge moving the barrier from one side of the centre lane to the other. Thus roadway capacity can be optimised with four lanes in the peak direction and three lanes in the off-peak direction.
The bridge was designed by the great Swiss-American engineer, Othmar Ammann. Educated at ETH in Zurich, he moved from Switzerland to the USA in 1904 and spent most of his working life with the Port of New York Authority. He is well known as the designer of six of the big bridges in New York including the George Washington Bridge over the Hudson River and the Verrazano Narrows Bridge, whose main span of 1298m held the world record for the longest span until it was surpassed by England's Humber Bridge in 1981.
Image: Wikimedia Commons, Paul Luffel
Plans for the seven lane bridge were initially opposed by the mayors of Gloucester City and Camden, who proposed a four-lane tunnel alternative, arguing that it would not blight the surrounding area like the bridge would. Happily good sense prevailed, with the bridge option handling more traffic, costing $24 million less and taking one less year to construct.
The new crossing was called the Walt Whitman Bridge after the 19th century poet and author who spent the last 19 years of his life in nearby Camden. The naming of the bridge was itself a subject of controversy, being opposed by some church leaders local officials who campaigned against naming the bridge after Whitman because of his homosexuality.
Image: Wikimedia Commons, Elliot from Cherry Hill, NJ
After a delay caused by the Korean war, work started in 1953 with the concrete cable anchorages dug nearly 20 metres deep on both sides of the river and the tower foundations going down up to 30 metres. Work began on the two 115 metre high steel towers in mid-1954, involving over 10,000 tonnes of steelwork fabricated at the Bethlehem Steel works in Pennsylvania. Cable spinning started in 1955 using about 60,000 miles of 5mm diameter high strength steel wire to form the 0.6m diameter main suspension cables. The final stages of construction were delayed by a prolonged steel strike, but eventually, on 15th August 1957 the bridge was dedicated and it opened to traffic the following day. The four-year-long project had cost $90 million and eight lives.
The Walt Whitman Bridge was named "The Most Beautiful Structure of Steel of 1957" by the American Institute of Steel Construction. I can't help wondering what it was up against.
The bridge underwent a major rehabilitation and upgrade in the mid-1990's. This seems to be a regular pattern; it is not uncommon for a major bridge crossing to have significant improvement works after about 30 to 40 years, usually because of rapid growth in vehicle traffic. The bridge currently carries more than 120,000 vehicles per day, peaking about 150,000. The $130 million project included widening and repairing the decks, replacing the deck slab on the approaches, installing an auxiliary support system at the hanger pin locations, inspecting for structural fatigue, and rehabilitating the bridge to comply with current seismic engineering codes.
Then in July 2007, shortly after the Walt Whitman Bridge celebrated its 50th birthday, the Delaware River Port Authority announced plans for a second major rehabilitation that would replace the bridge's existing deck with a lightweight orthotropic deck weighing 5,000 tons less than the old one. After an evaluation of various alternative options, the work was eventually carried using a steel grid system partially filled with lightweight concrete and completed in 2013.