Survarnabhumi International Airport Bangkok - Structure and form-finding

The terminal’s roof A 570 ? 200 metre roof spans the completely glazed terminal and covers, in addition, with its end segments, two large gardens. The roof rests on eight pairs of columns. Each pair supports a primary truss. The primary trusses are connected by the secondary trusses, which support the sun protection elements. All trusses were three-chord trusses of thick welded steel. The elevation of the trusses demonstrates a horizontal upper chord and a haunched lower chord, the geometry approximating the moment curve of a single-span girder with cantilever. Only in the area surrounding columns are there divergences from this principle. The section of the trusses was designed so that two chords are in compression, the third in tension. As a result of these considerations, the trusses received their characteristic, highly complex yet lucid form. Deflection along both the vertical and horizontal axes, as well as stability concerns could be dealt with optimally by the truss geometry, whereby the amount of steel required was kept small. The terminal’s facade Forty-metre-high guyed vertical struts which are connected by pre-tensioned horizontal tension-cables, constitute the primary structural members. The glazing is point-fixed to the horizontal tension cables. The concourses The concourses are made up of typical bays, a total of 104 identical three-chord trusses of varying depth. The membrane roof spans the 27 m between the trusses, alternated with glazing. For the membrane roof a team, including Werner Sobek Engineers, Transsolar, Laboratorium für Dynamik und Akustik, and the Murphy/Jahn Architects developed a three-layer membrane which could contend with the high thermal and acoustic demands. At the ends, intersections, and where the concourses dock onto the terminal, special types came about, with more than 4000 m2 of free spans.