July_1967 — Page 23

crypt, is in the region of £21⁄2 m. Overall cost since 1930 (including that of the site and the pre-war works) is some £4m.

Design Features

The 16 bays formed by the ribs of the lantern tower, each 66 ft. by 12 ft. wide, are filled by panels of colour- ed glass to a design by John Piper and Patrick Reyntiens.

Each window is a number of taper- ing rectangular sections containing concrete ribs forming irregular pat- terns. Under the method employed the external skin of coloured glass segments is jointed in epoxy mortar mounted on a frame of reinforced concrete. The largest panels weigh nearly two tons and incorporate about 100 separate pieces of glass.

Focal point for the beams of vari- coloured light transmitted from the lantern into the nave is the high altar. This is carved from a solid block of white marble, from Yugoslavia, weigh ing 8 tons and set on a recessed plinth of dove grey marble within the sanc- tuary.

Suspended above the sanctuary, the baldacchino, in the form of a 50 ft. diameter space frame of aluminium, fulfils both the liturgical requirement of a covering for the high altar and the functional needs of a mounting for heaters, lights, sound reinforcement equipment and а sound reflecting

canopy.

Construction of the nave floor is in grey and white marbles from Sicily with the addition of a lighter grey in the predella area,

The 90 ft. high main entrance porch and bell tower, forming an imposing introduction to the cathedral from the south, has as the central motif a de- sign, by William Mitchell, Des. RCA, AIBD, based on the three crosses and three crowns, carved into the Port- land stone face.

Solid sliding entrance doors, 12 ft. square and 2 ft. thick, are cast in a mixture including bronze powder and glass fibre backed by concrete, and incorporate a design by Mr. Mitchell based on the Gospel symbols.

From the main entrance porch the main axis of the cathedral terminates in the largest of the chapels, the Chapel of the Blessed Sacrament, seat- ing over 100, and with windows, re- redos and tabernacle designed by Ceri Richards. Above the entrance to the chapel is the organ

which is, in fact, a complex of six organs

and the north facade of this chapel pro- vides a background and canopy for an open-air altar facing the wide piazza formed by the new roof of the old crypt which merges indistinguish- ably with the podium area.

Contruction Methods

A start was made on the erection of the superstructure in 1962 by the installation of a Babcock-Weitz G. 280 B. tower crane, mounted on a portal- type base near the centre of the cathe- dral site. After having been a feature

Far East Architect & Builder July, 1967

of the Liverpool skyline for three years, it was dismantled from inside towards the end of 1965, in one of the first operations of its kind in Britain.

A major feature in the construction of the main frame of the building was the provision of falsework to support the structure. Structural steel towers and trusses were used, first to support the vertical columns and then to carry one end of the trusses supporting the buttresses. As re-uses of the false- work were possible the trusses then carried the main ribs and the towers to support the main ring beam.

The falsework also provided a basis for access to work in all elevated loca- tions. With the main structure com- plete. the supporting falsework was progressively released and the concrete frame became self-supporting. The trusses pivotted about their lowest points by screw threads at their upper points. The main ring beam was sup- ported on the steel towers by 128 specially designed screw jacks, which were progressively lowered until free.

Construction of the roof cone then proceeded with the erection of pre- cast concrete purlins spanning between the main ribs. On these were laid the roof slabs, also of pre-cast con- crete, incorporating an external sur- face of sheet aluminium with an in- sulating layer of foamed polyurethane between.

These slabs were manufactured on site under exacting temperature and pressure conditions. The pre-cast post-tensioned concrete pinnacles were also fabricated on site, using glass re- inforced plastic moulds.

Concrete mixes included 8,500 p.s.i. for the pinnacles; 5,500 p.s.i. for the lantern column and upper and main ring beams; and 4,500 p.s.i. for the bulk of other commitments.

Right: High altar-a solid block of white marble-above which the aluminium baldacchino, in the form of a 50 ft. space frame, is suspended from the base of the lantern tower

Below: View into baptistery from the nave

49