Client                                    Royal Botanic Gardens, Kew, London, UK

Architect                               John Pawson Architects

M&E engineers                     AECOM

Lighting design                     Speirs + Major

acdc products                      Q

Structural Engineer & Project Management       Buro Happold

Electrical Engineer               Atelier Ten

Cost Consultant                   Jackson Cole

Main Contractor                   Balfour Beatty

Electrical Contractor            Pococks

Summary

The award winning lighting of the Sackler Crossing at the Royal Botanic Gardens, Kew enhances the experience of this elegantly designed structure after dark. The S shaped bridge designed by John Pawson Architects floats just above the surface of the lake playing with solidity and transparency. Constructed on a concealed steel frame the deck consists of 100mm granite planks with 30mm solid bronze cantilevered vertical uprights providing the balustrade. The gentle S shape allows the crossing to have many facets from giving it the appearance of it being solid and then transparent when viewed from on the bridge or when viewed from afar. The bridge reflects in the water of the lake, but also the water is reflected in the bronze of the uprights. The appearance of the bridge constantly changes.

Design Brief

The lighting was sensitively handled in relation to the context of the gardens. As the Royal Botanic Gardens remains mainly dark at night, the bridge softly shimmers in the darkness giving a moonlit effect and reflects in the water of the lake. The crossing was not seen in isolation with low level floodlighting to specimen trees on the adjacent island creating visual interest and focal point in the landscape allowing the bridge context after dark.

LED Design Solution Over 1000 discreet custom high output white LED fittings are recessed in the granite planks of the bridge deck at either side, between each bronze upright gently washing light up their inner surfaces. The fittings were developed with the light  emitting diodes set low down in the fitting  to minimise the visibility  of the light source and an additional frosted glass front top plate eliminates any bezel being seen. The fitting  has very clean and crisp appearance that complements the minimal design of John Pawson.

The LED uplights were developed with electrical wiring loom and plug and socket arrangement to aid the installation eliminating the need to wire each fitting. The final specification  of the fitting  was confirmed after prototyping both the fitting and installation method with careful consideration  taken over the selection of LEDs in regard to colour appearance and the finish of the additional glass front top plate.