Located in the City of London, New Street Square Bridges play a key part of the ongoing improvement and expansion of Deloitte’s central London “campus”.  The new bridges connect Nos. 1 and 2 New Street Square, which built 15 years apart, are different in design with a change in levels between them.  The brief was to connect two different client facing areas on the respective first floors of each building, and two staff-only areas, including the main restaurant, on the 7th floor.  The design responds imaginatively to multiple constraints; the level change, the interface with contrasting building faces, the need to provide adequate step free access, the desire to provide more than a transitional space on the bridge itself and a planning requirement stipulating lightness of appearance and transparency.

The team, including engineers Eckersley O’Callaghan, came up with the concept of a switchback ramp on each bridge that dealt with the level change entirely within the bridge environment itself. An inclusive arrangement of steps and ramps, different for each bridge, resolves accessibility requirements as simply as possible, avoiding the need for a platform lift and loss of valuable floorspace within either building. The ramp also allows for breakout areas on the bridge itself, creating spaces to sit, talk or work, turning these otherwise transitional environments into part of the wider office. The result leaves the bridges feeling as an extension of the floorplates at both levels rather than just a bridge between them. 

The bridges are articulated as linked monocoque structures with stepped steel bridge floors - gaining far greater strength, through increased rigidity, than a conventional flat section. The glazing of the bridge walls is also stepped to create inherent strength, allowing glass panels to support the lightweight roof without the need for structural mullions.  Each façade has been carefully adapted to receive the bridges in a unique way; they appear to float through No.1 Street Square however they abut No.2. Localised heating, cooling and ventilation is provided via a series of ‘trench’ units recessed into the floor of each bridge and positioned to help offset cold downdraughts and solar gains.

Principal external materials – glass and stainless steel – were selected to complement the adjoining buildings and reduce the need for frequent maintenance. Self-finished and naturally robust, both materials can withstand harsh conditions without corrosion and neither degrades under UV light. The bridge roofs are formed from carbon fibre and incorporate skylights to improve the internal bridge environment, and further reduce the bridges’ apparent mass to the observer. Other materials and finishes, such as polished mirror on the underside of the decks, have been carefully selected to give the bridges a shimmering transparency when viewed from the street, and reflect back impressions of the surrounding townscape.