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Source: istructure (ID: istructure2017)
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The column in the building has the function of architectural expression and structural stress
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As one of the important forms of column performance, the pursuit of fine design and ultra-thin column brings greater challenges to architects and structural engineers
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Le Corbusier put forward “five points of new architecture” around 1926, which had a far-reaching impact on modernist architecture
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The first one is “supporting of ground-level pilots, elevating the building from the earth under the standard to extended to space.”
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Columns are one of the key elements that need to be carefully designed by architects and structural engineers
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Villa Savoye, 1930, Wikipedia,) valueyou villa Savoye, 1930, designed by Le Corbusier, has an overhead open space on the first floor, only retaining the structural columns around the building
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The white concrete column spacing of Savoy villa is 4.75m, the column height is 3.13M, and the section diameter is 250mm
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The ratio of column length to diameter reaches 12.5, which is very simple and slender compared with the heavy column in classical architecture, showing a refined architectural performance
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With the development of engineering materials and technology, the building no longer relies on the thick and dense stone columns to support the load
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After architects and engineers constantly explore, try and innovate, there are three kinds of differentiation in the design form of columns
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1、 Pursue the effect of thin and light column section, namely thin column (slender column)
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The key problem of thin column structure is compression stability, and its material strength can not be fully utilized
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The critical stress of Euler stability is the limit which is difficult to break through
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In the works of the modernist architect Mies van der Rohe to realize his space concept “lessismore”, the “Mies column” often used is the typical thin column
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Taking Barcelona Pavilion (1929) as an example, the column is 3.1m high and the cross section is unusual
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From the perspective of structural stress, the “radius of gyration” of cross section is smaller than that of other sections, and the slenderness ratio of column is larger, so it is a thin column in the sense of mechanics
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[Note: the side length of the cross column (305 mm) of the German Pavilion of Barcelona International Expo is larger than that of the column of villa piavoy (250 mm), but the “radius of gyration” of the cross section is smaller, and the slenderness ratio of stability calculation is larger
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]Cruciform steel column of Barcelona Pavilion, 1929 ﹥ Wikipedia hanspeter Schaefer mushroom column of Johnson wax headquarters, Frank Lloyd Wright, 1939 ﹥ Libra ryofCongressbyCarolM.Highsmith 2、 The pursuit of a small number of columns, the column “condensation” into a small and thick column
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The image of the giant column is heavy and full of momentum
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Generally, there is no stability problem in its structure, and the material strength is given full play
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Therefore, the column design is more free, its section is not limited to square and round, can shape a variety of characteristic sections
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Take the Turin worker’s Cultural Palace designed by Pierre Neville as an example
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Huge columns and radial steel beams make up one umbrella after another
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Each “umbrella” is an independent unit, supporting a very open internal space (the column spacing is 38mx38m)
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The cross section of the lower section of the giant column is a cross section, and the upper section is gradually reduced to a circular shape, presenting a rough and straight image
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Palazzo del lavoro, Cultural Palace of Turin workers, 1959, Neville, source: www.stilemarete.it ”© stilemarete.it 3、 The column geometry is “discrete” into a number of branches, and the topological evolution forms bifurcation or weaving, which is collectively referred to as “tree column” or “bifurcation column”
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The tree column changes the load transfer from one point to many points, and provides more load transfer paths
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Tree column branches can reduce the span of the roof structure, which is conducive to the formation of larger span space
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Taking terminal T2 of Shanghai Pudong Airport as an example, a beam string roof structure supported by Y-shaped inclined columns is adopted to create a light and lively super large space
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The two-stage bifurcated tree column can effectively reduce the span of the beam string of the roof and improve the clear height of the building
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The designer has done fine processing to the tree column components and node details, and the architecture structure integration design makes the structure become the highlight of architectural expression
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Shanghai Pudong Airport Terminal T2 tree column / bifurcated column ﹣ Zhou Jian 2 thin column implementation method for the first classification of column design form – thin column, in order to pursue the exquisite design of columns, the ultimate slender, architects and structural engineers jointly meet the challenge
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The following is a brief analysis of several classic cases of using thin column technique, and summarizes several methods to realize the design of thin column
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The light load thin column is prone to failure under the structural pressure
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In order to prevent instability, it is necessary to reduce the axial pressure of the column, that is, to reduce the pressure load of a single column
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The Serpentine Gallery, designed in 2009 by meshima and Nishizawa, is supported by thin columns and continuous aluminum plates, which reflect the images of trees, ground and sky and echo the surrounding environment
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The thin column in the gallery only bears the weight of one layer of light roof (aluminum plate), and its load is only about 1 / 20 of the constant live load of ordinary concrete floor, which is about 1 / 5 of the constant live load of ordinary building light roof
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Moreover, the Serpentine Gallery is a temporary building, and the probability of encountering strong wind and earthquake during its use is very small
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The horizontal force is hardly considered in the design, so its columns are much thinner than those of ordinary buildings
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Autumn 2009 Serpentine Gallery, Sanaa, 2009 iwan.com In order to prevent the instability of thin columns, another way to reduce the axial force of columns is to increase the arrangement of columns, so as to reduce the pressure load on each column
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In the early design of the park cafe, MeiDao Heshi used 1.5 m x 1.5 m small column net to realize the design of thin columns
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In large buildings, dense columns may lead to cramped and messy space, so it is not common in design
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The more successful case is the Stade mat Atlantic designed by Herzog and de Mellon
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The Atlantic stadium in Bordeaux has a roof supported by slender, dense columns
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The pure white dense columns, like bright light or water drops, dissolve the huge rectangular sense of the stadium into invisibility, creating a dynamic space
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The fine lines of the columns also contribute to the open facade of the building.
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