Geometry Meets Music

The Philips Pavilion was a temporary structure designed for Expo '58 in Brussels. The design was done by Le Corbusier in collaboration with the Greek composer Iannis Xenakis, an architect and engineer, who carried out most of the designing. 

The goal was to build the pavilion to demonstrate the sound and light possibilities of Philips' technologies in those days. The structure supposed to be self-supporting and column-free, a hollow structure with the acoustic qualities. Xenakis found a solution for the shape of the building in a series of conjoined curved planes forming a tent-like enclosure. 

The chosen design was a cluster of nine hyperbolic paraboloids with a stomach-shaped floor plan (shown on the model below). Over 500 spectators might have been accommodated inside the pavilion for an eight-minute spectacle of light and sound called Poème électronique, by composer Edgard Varèse. People were sitting and lying in the darkroom and watched visual effects along the walls of the pavilion.

Following video is a short presentation of the used design and its geometry. 

The final structure was 22 meters high and certainly pushed the limits of engineering of that time.

To build such a complex form, Xenakis proposed a structural system of prefabricated concrete panels hung in tension on the 7 mm wire cables, laid on both sides of the shell. An ingenious solution also included about 2000 precast 5 cm thick panels, built in a hangar shed on simple sand moulds that matched the curvature of the pavilion. The size of the precast slabs was about 1 square meter with a light reinforcement mesh to prevent breakage during transportation to the site.

Moulded sand hill for casting panels

The steel cables were positioned inside and outside of the shell, following the ruling lines of hyperbolic paraboloid geometry, and anchored to the concrete ribs and foundation beam that formed the base of the pavilion. The "Strabed " system used for mounting prestressing cables. Once the panels were erected, the entire structure had been post-tensioned, making a monolithic structure. The outside of the shells including the prestressing wires were covered with aluminium paint and the interior plastered with a sound-absorbent layer of asbestos felting.

The precast slabs had been placed in the position and filled with mortar. After that, the prestressing wires were tensioned with a special jack.

At the edges of each hyperbolic paraboloid shell (lines of intersection), were cylindrical concrete ribs, 40 cm in diameter, as the structural elements cast in situ. The scaffolding wooden beams followed the ruling lines of the hyperbolic paraboloid shells.

The image below shows the numerous prestressing wires of high-tensile steel, which were applied on both surfaces of the shell and left visible.

The original pavilion was demolished in 1959. In recent years, there have been attempts to rebuild the pavilion in the hometown of the Philips Company, Eindhoven, Holland.

This work of art represented a phenomenon through its synthesis of architecture, visual media and music, and left its mark on history.

The construction process of the pavilion is quite remarkable as detailed in the enclosed article. The used methods of construction were both material and labour intensive. At that time, almost 60 years ago, those methods were the only possible.

The thin concrete shells are not as popular as they once were, in the golden era of concrete shell structures prior to 1968. Recent advances in concrete technology should affect the cost of construction and may help revive the interest in this structural form, particularly the hyperbolic paraboloid form. 

Source: Construction of the pavilion in prestressed concrete, by H.C.Duyster 

Image Credit: ArchDaily

Note:

This post is a part of the larger post about one of my favourite geometric forms, hyperbolic paraboloid, or shorten - hypar, Magnificent Hyperbolic Paraboloid.