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rete DeWitt Chestnut Apartment Building in Chicago. The most significant use of this system is in the twin structural steel towers of the 110story World Trade Center building in New York. Columndiagonal truss tube. The exterior columns of a building can be spaced reasonably far apart and yet be made to work together as a tube by connecting them with. Diagonal members intersecting at the center line of the columns and beams. This simple yet extremely efficient system was used for the first time on the John Hancock Center in Chicago, using as much steel as is normally needed for a traditional story building. Bundled tube. With the continuing need for larger and taller buildings, the framed tube or the columndiagonal truss tube may be used in a bundled form to create larger tube envelopes while maintaining high efficiency. The i10story Sears Roebuck Headquarters Building in Chicago has nine tubes, bundled at tile base of the building in three rows. Some of these individual tubes terminate at different heights of the building, demonstrating the unlimited architectural possibilities of this latest structural concept. The Sears tower, at a height of 1450 ft (442 m), is the world39。s present tallest (714 ft or 218m) lightweight concrete Building in Houston. Systems piling both concrete and steel have also been developed, an example of which is the posite system developed by Skidmore Owings 6 and Merrill in which an exterior closely spaced framed tube in concrete envelops an interior steel framing, thereby bining the advantages of both reinforced concrete and structural steel systems. The 52— story One Shell Square Building in New Orleans is based on this system. 指導(dǎo)教師審閱意見(jiàn) : 指導(dǎo)教師: 年 月 日