Text A. Space frames and geodesic domes

As with the post and lintel or the arch, so the truss can be extended in three dimensions, forming a new type of structure. The truss extended in three dimensions becomes a space frame. It can be supported at any of the junctures of its members permitting large cantilevers, as in McCormick Place, Chicago, 1970-71 by CT F. Murphy and Associates. Sub­stantial three-dimensional trusses, built up of tubes of steel, have a clear span of 342 feet (104.2 meters) and carry the roof slung on their underside.

Just as the arch can be rotated to form a dome, so a truss can be curved in three dimensions to form the "geodesic dome". Like the truss, this is built up of small, light, easily handled steel members.

Shells

Another structural type employs shells. Typically constructed of concrete, shells can be very thick and heavy or extremely thin and light. The American architect Eero Saarinen was interested in shell forms and used a portion of a sphere cut to a triangular plan in his Kresge Auditorium at Massachusetts Institute of Technology.

He devised sweeping, reinforced concrete cantilevered shells for the Trans World Airline Terminal at Idlewild (Kennedy) Airport, New York, 1956-62. The total covered space is 212 by 291 feet (64.6 by 88.7 meters), with enormous cantilevers at the ends of 82 feet (24.9 meters). Typically the edges of such shells are subject to significant internal stresses and deformation so large beams run along the edges of such shells to stiffen them. The feet-shaped piers that support the cantilevered shells are packed with reinforcing rods to take up the tensile stresses generated by the 82-foot overhangs.

It is possible to build shells with much less material, as a Mexican architect Felix Candela demonstrated in a number of buildings in the 1950s and 1960s. A good example is his restaurant at Xochimilco, Mexico, 1958. The concrete is only about 4 inches (10.2 centimeters) thick. The rigidity of the structure is a function of its double curvature, for it is curved.

A shell may also be curved or folded in only one direction. A good example of this is an accordion-fold shell, as in the Minneapolis International Airport Terminal building, 1962-63 by Cerny Associates. A particularly interesting use of a folded shell is in the Assembly Hall at the University of Illinois Urbana, 1961-62, by Harrison and Abramovitz, with the engineers Ammann and Whitney. This dome consists of a folded plate, 394 feet (120 meters) in diameter, which rests on a series of radial supports reaching upward from a footing ring at the base. The enormous lateral forces are taken up by a belt of almost 622 miles (1,000 kilometers) of steel wire wound under tension around it.

Exercise 4. Translate the words:

arch, post, truss, dimension, structure, span (v., n.), cantilever (v., n.), roof, tube, dome, curve, rotate, form (v., n.), handle, steel, member, construct, triangular, reinforce, shell, rigidity, fold, base, stiffen, juncture, belt, double, edge, rest on, carry.

Exercise 5. Choose the right translation from A to B:

A: juncture, rotate, belt, rest on, edge, radial, double, design, curve, tube, enormous, curvature, shell, fold, employ, stiffen.

B: складка, вращаться, лента, проект, труба, край, опираться на, шов, радиальный, двойной, изгибать, применять, огромный, изгиб, оболочка, придавать жесткость.

Exercise 6. Are these meanings correct or incorrect? Correct the mistakes:

wire – проволока

edge – край

rest on – опираться на

design – дизайн

stiffen – армировать

belt – лента

arch – арка

employ – нанимать

fold – сгибать

double – двойной

roof – крыша

span – пролет

shell – раковина

Exercise 7. Translate the following word combinations:

post and lintel construction, footing ring, space frame, considerable distance, substantial three-dimensional truss, steel tube, easily handled steel member, shell form, triangular plan, reinforced concrete cantilevered shell, total covered space, significant internal stress, feet-shaped pier, reinforcing rod, tensile stress, double curvature, lateral force, steel wire.

Exercise 8. Translate the following words as nouns and verbs:

space, span, design, cantilever, form, concrete, stress, plan, fold, shape, support, function, use, reach, force, subject, place, mix.