Influence of the Willis Building on Recent Glass Curtain Walls

The collaborative realization of a frameless curtain wall became a foundation for Foster’s future work with manufacturers and engineers to develop previously untested glass details. He continues to push the technical limits of glass construction, completing notable glass buildings including the Reichstag addition in Berlin (1999), the Great Court of the British Museum (2000), and the Swiss Re Tower in London (2004). Moreover, the Willis Building challenged

FIGURE 3.21 Photos of the southwest side taken about an hour apart during dusk. The mechanical equipment on the ground floor slowly becomes revealed as the light inside becomes brighter than the exterior light, and the reflections of surrounding buildings become merged with the equipment.

Photograph: Author (2019).

the natural skepticism for frameless curtain walls, giving confidence to glass engineers and architects; its glass details became an impetus for a multitude of frameless curtain wall types. Martin Francis, a key collaborator on the Willis curtain wall and a member of Foster’s office for 20 years, co-founded Rice Francis Ritchie (RFR) with structural engineer Peter Rice and architect Ian Ritchie. RFR would become renowned for their suspended glass system using a two or four-point bolt connection commonly known as the “spider” fittings. In 1981, RFR began collaborating on the suspended glass wall of the three Serres (greenhouses) along the exterior of the Cité des Sciences et de l’industrie by Adrien Fainsilber at the Parc de la Villette in Paris (Figure 3.22). The architect referenced the Willis Building’s state of the art glass technology and proposed transparent rectangular volumes that serve as transition zones between the park and the museum. The wall comprises a two-meter square grid of glass panels suspended by four-point fittings attached to cable trusses, which are

FIGURE 3.22 Serres at Cité des Sciences et de l’industrie (1986) by Adrien Fainsilber, Paris.

Photograph: Carl Campbell.

tensioned against steel columns. The system accommodates greater movement in distance and angles than the Willis Building’s bolted glass panels, which are attached to a relatively rigid concrete frame. Peter Rice credits the Willis Building for the “know-how and the confidence necessary for suspended structural glass system.”³⁰ The bolted suspension system was further applied to the Louvre Pyramid (1989) and would become a symbol of high-tech glass architecture in the 1990s.

The perception of glass at the Serres differs from that of the Willis Building. The glass planes of the latter are made legible from the interior by the silicone joints and the reflective edges of the vertical glass fins. When viewing out from the interior of the Serres’s suspension system, the glass planes are defined by the series of points and lines of the metal fittings; the glass sheets by contrast are dematerialized by light shining in from the outside (Figure 3.23). When viewing from the outside in daytime, in both buildings the glass becomes visibly present by the reflections captured on the smooth surfaces. At both Serres and the Louvre Pyramids, the hardware of the suspension system visually dominates and, in some ways, makes the buildings less transparent. The glass and reflections appear to fall to the background, while the eyes are drawn to the dense field of jewel-like, precisely machined and polished metal hardware. By comparison, the patch plates of the Willis Building are finished in matte dark gray to merge with the glass tint and allow the effects on the glass to be foregrounded. The Willis Building has had an undeniable influence on the Grand Projets under François Mitterrand, as well as on other High Tech architecture worldwide.

FIGURE 3.23 Serres at Cité des Sciences et de l’industrie (1986) by Adrien Fainsilber,

Paris. When viewing out front the interior of the suspension system, the glass planes are defined by the series of points and lines of the metal fittings.

Hugh Dutton Associés.