2008 I moved cable stayed br. lecture up. Cable stayed has ... · A collection of Menn bridges to...
Transcript of 2008 I moved cable stayed br. lecture up. Cable stayed has ... · A collection of Menn bridges to...
2008 I moved cable stayed br. lecture up. Cable stayed has some Menn stuff in it but without the write context, they do not know ETH yet, they do not know the swiss story at all. So, the order is off they have already seen Sunniberg, but they don’t know why or who or how. need to fix that.
2012 I think Sunniberg is pulled from cable stayed and should come back here. but have not the time tonight to fix it.
A collection of Menn bridges to whet the appetite for exploring bridges today, then transition to Menn’s classic favorite.
14-01 landwasser viaduct_150dpi.jpg
We begin back in the Graubunden, Switzerland’s largest and least populous canton.This is the region where Maillart’s greatest works occurred and where, between 1957 and 1970, a new series of bridge forms would appear, crafted by the third of our Swiss structural artists, Christian Menn, a native of the Graubunden.Menn’s favorite structure in the canton is the landwasser viaduct, a stone structure of 1904 which essentially ends thousands of years tradition in the design of plain masonry structures. The bridge is light and elegant for its material and is free from extraneous decorationIt is also curved!!
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The Graubinden has long been a draw for artists, especially picturesque mountain towns like Davos
Davos also functioned as a tuberculosis refuge for Europe. The mountain airs could cure you.
14-04 tavanasa bridge_150dpi.jpg
Nearby at Tavanasa we find Maillarts first masterpiec of the hollow box form
14-07 maillart tavanasa designs_150dpi.jpg
Maillart proposed designs for Tavanasa after 1927 avalanche destroyed original version..Along with several other possibilities of more standard arches.The top looks quite similar to the valtschielback which was completed two years priorAnd the bottom is also deck-stiffened, but with a different approach treatment, though still retaining unnecesasry heavy piers at the abutment.
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Maillart lost the commission, but the actual bridge looks remarkably like his third design, except that the designer did not use the deck stiffness and so has an over heavy arch
14-09 tavanasa bridge_150dpi.jpg13-61 valtschielbach bridge_150dpi.jpg
Maillart lost the commission, but the actual bridge looks remarkably like his third design, except that the designer did not use the deck stiffness and so has an over heavy arch
photo SRA
It was in the next year, 1928 that Maillart won the commission to design and construct the Salginatobel
Where finally he completely frees himself from any vestige of stone tradtion.
His style in hollow boxes has matured
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The 1933 Thur bridge at Felsegg has an arch form which is broken at the apex.
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This is due to heavy live loads at the site which made him desire a deeper section at the quarter points.
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Greater width also led to lighter cross frames rather than the transverse walls of Salginatobel and multiple parralel hollow boxes
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In the Vessy bridgeof 1936, near Geneva, he used a very flat broken arch
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And in a competition for a bridge at Bern he again altered the form tomore clearly express the hinges by moving them out into the span.
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The 1940 Lachen Bruidge presents a more sculptural aspect because he used two hollow boxes to accommodate the skew crossing.
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And as at the Bern proposal Maillart more clearly expresses the presence of the hinge.
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And as at the Bern proposal Maillart more clearly expresses the presence of the hinge.
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Finally, in 1940 at Garstatt, the arch is so altered that it in some sense ceases to be an arch
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But rather a form of two triangles. The goal is strucural : deeped quarter points, and constructural : easier formingThe bridge looks heavier, and perhaps even appears through illusion to bulge downward, and is not as visually effective as Vessy and Lachen.It illustrates the directions in which Maillart may have been thinking at the end of his life, flatter forms with fewer curves. Do these presage prestressed concrete forms?
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As Maillart was continuing to hone his designs, others were proposing essntially sculptural solutions to the bridge problem, such as this by Paolo SaleeriA tubular concrete form which would have been very wasteful of materials.
wikipedia: Paolo Soleri (June 21, 1919, Turin, Italy) is an Italian-American visionary architect with a life-long commitment to research and experimentation in design and town planning. He established Arcosanti and the educational Cosanti Foundation. Soleri is a distinguished lecturer in the College of Architecture at Arizona State University and a National Design Award recipient in 2006. [BWS note: Arcosanti is a sort of dense urban utopia vision, that actually exists outside of Phoenix]
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We now spend a little time at VessyWe would like to illustrate how suprising and pleasing new forms can arise from the engineers creativity rather than from sculptural or architectural flights of fantasy.
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Here Maillart attacked the one part of the bridge he had not yet truly innovated with, typical of his piece by piece approach, the cross wallsThe X-form here is suggested by his calculation, but not so dictated. The X-s mimic the bending moment diagram for the walls under side loads.
14-25 leipheim bridge_150dpi.jpg
Vessy is contrasted with the Leipheim bridge of 1937 which was an admitted copy of Maillarts three hinged style. The final form finding here was done by an architect, and the structure lacks the visual surprise of Maillart’s efforts.Even the details seem clunky
14-28 leipheim bridge section_150dpi.jpg14-29 vessy bridge section_150dpi.jpg
And the cross section at Leipheim is much heavier, by a factor of three
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Profiles of the structures demonstrate that the leipheim effort, while nice, is lacking (really? Vessy is pretty intense) True enough. This is not an obvious comparison, but nonetheless a good one for discussion.
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This form has deep symbolic affinity with the geometric creations of the painter Paul Klee
Who was, like Maillart, from Bern, and who had his studio in Bern at the same time Maillart was designin there
Klee was deeply involved with buildings, having taught at the German Bauhaus in the 1920’s
He died in the same year as Maillart, 1940
wikipedia: Paul Klee (IPA: kleː) (December 18, 1879 to June 29, 1940) wasa Swiss painter of German nationality.[a] He was influenced by many different art styles in his work, including expressionism, cubism and surrealism. He and his friend, the Russian painter Wassily Kandinsky, were also famous for teaching at the Bauhaus school of art and architecture. Today (2007), a painting by Paul Klee can sell for as much as $7.5 million. A museum dedicated to Paul Klee was built in Berne, Switzerland, by the
Italian architect Renzo Piano. It opened in June 2005 and houses a collection of about4000 works by Paul Klee.
14-37 salginatobel bridge scaffolding_150dpi.jpg
Meanwhile, as the scaffolding was up at salg. A mathematics teacher in the town which sponsored the bridge, Schiers, decided to leave his school and study himself, to become a civil engineer
14-38 pierre lardy_150dpi.jpg
He earned a Doctorate at ETH, and it is thus that, in 1945 Pierre Lardy became next in the line of great teachers at ETH, in the tradition of Culmann and Ritter.At ETH Lardy would train a remarkable run of students, among them Christian Menn and Heinz Isler, who would become premier structural artists in the same way that Ammann and Maillart did from Ritter a generation earlier
14-39 salginatobel bridge_150dpi.jpg
Menn first learned of Maillart and his designes from Lardy and would mimic his forms in his early bridges.Salg would be a model for
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Menn’s own deck-stiffened effort at Crot in 1960
Menn’s early work was all in his home canton of the Graubunden
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And Menn’s crestiwald, seen here undergoing a load test, or a traffic jamThe traffic jam here is caused by Swiss army artiller practice
14-47 valtschielbach bridge_150dpi.jpg
And deems it worthy of his complete trust despite its fifty years of Swiss winters
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And the scaffolding of the first of his 100 meter spans, the Reichenau
SGB to BWS: “It is a photo of a framed picture. Reflection from glass. It is in The Development of the Long Span Bridge by Tom Peters and others published by ETH based on an exhibit circa 1979.”
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Similar form, but not lengthening in span!
Seen here as completed in 1964 span 98 metres compare salg 89 metres, tavanasa 51 metres
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Similar form, but not lengthening in span!Seen here as completed in 1964 span 98 metres compare salg 89 metres, tavanasa 51 metresNarrow polygonal, widely spaced verticals
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With a roadway curved only at the approaches. (recal Valtschielbach vs. Schwandbach)
14-53 reichenau bridge_150dpi.jpg
Here we see high up on the arch the holes which are there two receive the dynamite to destroy the bridge should the countrybe invaded.All Swiss bridges and tunnels are so equipped, the thinking being that the Swiss will have a natural advantage in the hard to travel mountains without proper roads.
14-54 reichenau bridge_150dpi.jpg
The verticals at Reichenau can be more widely spaced because of the advent of presetressing, and the savings is in labor costsThe decks are themselves hollow box prestressed concrete girders (the hollow box and the deck stiffener arch combine!)This sparse design allows arches of very great thinness, and decks which are themselves lighter than Maillart’s RC designs as we see here in the Nanin and Cascella bridges of Menn also in the Graubunden.
14-57 the palace at 4am by albert giacometti_150dpi.jpg
One can perhaps envision a connection to the sculptures of Alberto Giacometti who also prized lightness
Unsursrisingly, Giac. Is from the Graubunden, where the landscape itself is sparse
wiki: Alberto Giacometti (October 10, 1901 – January 11, 1966) was a Swiss sculptor, painter, draftsman and printmaker
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And where Menn’s Salvanei bridge seems to fit well with the landscape
14-58 salvanei bridge_150dpi.jpg
And where Menn’s Salvanei bridge seems to fit well with the landscape
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In 1970 Menn won an international competition for a crossing of the Aare river outside of Bern
14-60 felsenau bridge section_150dpi.jpg
He designed a prestressed concrete, hollow box cantilever for the Felsenau crossing
14-61 cantilever girder design_150dpi.jpg
The shape of which is influenced again by the shape of the bending moment diagram of a cantilever.
14-62 felsenau bridge prestressing tendon layout_150dpi.jpg
Here we see in red the prestressing tendons, more of which are necessary near the supports, where moment is highest
14-64 revolution of the viaducts by paul klee_150dpi.jpg
We might be reminded of another Klee work, the revolution of the viaducts
14-65 felsenau bridge construction_150dpi.jpg
In the hollow box under construction we see the plain reinforcement and the conduits to hold the prestressing tendons.
14-66 christian menn at felsenau bridge construction_150dpi.jpg
Herr Menn is there overseeing the work looking out on his creation
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And now the cantilevers have almost met in their progressing construction.
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The completed bridge shows the evolution of the prestressing idea from the plain boxes of Finsterwalder etc.Here Menn takes the single hollow box, and makes it deeper but narrower at the piers to lend stability. The resulting is a 3D interplay of shapes which makes the structure attractive.note also the two walled towers rather than hollow box.Als deck is cantilevered out from the hollow box
14-70 landwasser viaduct_150dpi.jpg
In perhaps a similar way to Menn’s favorite structure, the landwasser viaduct.
This example of remarkably light use of stone in the Graubunden and its great sculptor
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Giacometti, who was able to minimize even the human form in some of his work
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Menn’s Ganter bridge completed in 1980 illustrates how a striving for efficiency and economy can lead to entirely new forms in structural art
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Not only is the final form striking, but the bridge under construction presentd an interesting profile to the countryside during the three year construction
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Being supported only by a light scaffold and seeming to reach towards one another
photo SRA
And finally reach, giving us a brand new form in Presetressed concreteThe stays are there to shorten the cantilever spans, whichg would have been much longer than FelsenauThe tall tower is due to local conditions which provided the only solid bedroxk thereThe roadway is curved so the stays need to be encasedThe towers are hollow boxes due to height, but very widely spacedMenn wanted something above the roadway to balance the aesthetics
photo SRA
As the curious triangular walls/stays present a strange perspective.
As with all great bridges, different perspectives provide different views, not all of which are equally light at all times.
photo SRA
The valley has been altered by engineering, whether for the better or worse is for you to decide, but for a road I think we did not badly here
14-83 salginatobel bridge_150dpi.jpg
Menn realized that he had actually buitl a Maillart bridge upside down, having earlier copied him right side up
http://is-beton.epfl.ch/Photos/Small/I/I34/I34-12.jpg
Chandoline over the Rhone 1989 – C. Menn
140m main span, slight horizontal curvature necisstitated the out-of-plane stays at the ends.
All concrete – including concrete trussing of deck
Tower/mast shape interesting but logical?
The epiloge is that Ganter inspired Menn to investigate cable stayed forms further such as here at Sunniberg
photo SRA
photo SRA
Ben: the towers are quite low, the cables quite vertical – what is the difference between low and high towers? A horizontal cable is pre-stressing – a cable going to a tower is cable-stayed... Where is the dividing line?
JSE Billington article
Pier, pylon, cables, and deck each designed to satisfy technical requirements and aesthetic requirements.
Pier(below road), pylon(above road): pier and pylon are integrated. Pier shape expresses the pier bending demands for live loading on one span.
Pylons are flared: (1) visually interesting, (2) allows cables to remain straight as deck curves (3) resists bending due to curvature for LL on 1 span
Cables: low slung = high tension, deck thickened near piers to resist compression there.
Deck: continuous thin line, no expansion joints, breathes laterally as needed
In the same valley as Salginatobel.
mentioned briefly in the sable-stayed lecture we touchdown in Boston again briefly to see how Menn’s ideas faired in this situation
http://www.deuring.ch/christian-menn/english/projekte_e/zakim_e.htm: “The new Leonard P. Zakim Bunker Hill Bridge is the only one of its kind ever built. In addition to being the widest cable-stayed bridge in the world, the bridge will be the first "hybrid" cable-stayed bridge in the United States, using both steel and concrete in its frame. The main span consists of a steel box girder and steel floor beams, while the back spans contain post-tensioned concrete.”
lost in translation??
Engineering is always creative, otherwise it is not engineering. – troyano recently compiled a tome on bridges
14-85 marie-claire blumer maillart with christian menn_150dpi.jpg
Here is Menn describing something to Maillart’s daughter on the bridge looking good
Give some time at the end of class to start organizing groups. Also try to ease their fears about group work.
The epiloge is that Ganter inspired Menn to investigate cable stayed forms further such as here at Sunniberg
14-28 leipheim bridge section_150dpi.jpg
And the cross section at Leipheim is much heavier, by a factor of three
14-49 reichenau bridge scaffolding_150dpi.jpg
And the scaffolding of the first of his 100 meter spans, the Reichenau
SGB to BWS: “It is a photo of a framed picture. Reflection from glass. It is in The Development of the Long Span Bridge by Tom Peters and others published by ETH based on an exhibit circa 1979.”