A curved enclosure formed by glazed steel ladder trusses
The building houses 12 courtrooms on two upper levels, separated by custodial stair and service towers, and constructed of cast in situ concrete frames with blockwork infill. The courthall, which gives access to the courtrooms, runs at the north side. In contrast to the solid construction of the courtrooms, it is a light and spacious curved enclosure formed by six glazed steel ladder trusses which spring from the upper ground floor, rise over intermediate floors and terminate at high level at the staircase towers.
Each ladder truss is formed of a pair of curved 193.7mm diameter CHS booms, which are pin-jointed to brackets at top and bottom connections.
Cross-frame members and projecting tapered struts to which the solid rod ties are connected, are welded to the CHS booms.The disposition of the struts and ties along the curve reflects the structural forces.
The trusses are glazed with faceted frameless doubleglazed units, supported by stainless steel arms which are fixed directly to CHS crossframe members. The glass edges are bonded to rigid insulated aluminium panels; the lower edge of each panel is curved to follow the line of the truss and is connected with a double extruded silicone gasket to the adjacent CHS boom. A series of 219.1mm-diameter CHS purlins run between the trusses to support insulated solid panels which follow the curve of the trusses. They are lined on the inside with semiperforated trapezoidal steel liner sheets with polyester powder-coated finish. On the outside, they are clad with terne-coated stainless steel.
The edge of each panel is connected to the adjacent CHS boom by a double extruded silicone gasket.