Cathedral gets a lift — hydraulically

The refurbishment of one of Western Australia’s oldest Catholic cathedrals received a boost recently with help from hydraulic technology and the skills of riggers.

The gentle delicate hoist of just millimetres at a time was taken so the upper levels and roof structure of St Mary’s Cathedral in Perth could be lifted clear of the lower levels to relieve the weight on columns, arches and structures as the cathedral was widened and walls removed while being refurbished as part of a $25 million restoration.

The Enerpac Flat-Jac 700 bar cylinders employed are the same compact type used for confined space lifts across a wide range of industrial applications, including mining, electrical and manufacturing machinery as well as bridges and buildings.

The St Mary’s Gothic Revival cathedral — the oldest part of which dates to 1865 — is being restored to maintain its structural integrity and heritage value while eliminating rising damp, structural weakness and a crumbling bell tower. The project will integrate parts of the cathedral built in the 19th and 20th century and provide additions so up to 1200 people can be accommodated.

“Naturally we had to take great care to preserve the integrity of this fine old building, which the Heritage Council of Western Australia says has been a landmark since the first part was built by the Benedictine brothers in 1865,” says Rob Nolan of Onsite Engineering (OSE) Pty Ltd.

OSE installed a temporary steel framework on which to place multiple Enerpac single-acting low height RSM 10 tonne cylinders to lift the upper structure so it could ultimately be located on a permanent steel structure. When this was in place, walls below could be cut out and the building reconfigured to accommodate a wider and larger roof span, where one old section joins into a new section. (The lift was undertaken just clear of the scaffolding line in the pictures attached, to open up the area below.)

Powered by a lightweight (15 kg), powerful and portable Enerpac PUJ 1200E electric pump, the compact cylinders were selected because they could be fitted into the sometimes confined spaces in which they were required to lift, being only 43 mm high before plunger extension.

The compact flat design of the 5–150 tonne capacity range is designed for use where most other cylinders will not fit, with starting heights ranging from 32–100 mm.

“We had to lift from 10–12 points at once, using the pump/cylinder and instrumentation combination to hoist to the point when we could pack beneath the cylinders to support the weight evenly, safely and securely,” said Mr Nolan. Great accuracy was required as some sections, points support greater weight, necessitating different pressure, while not overloading others.

“The permanent steel support structure was then constructed and the load transferred onto it by re-jacking with permanent packing and grouting for stability. The lifting operations were trouble free,” said Mr Nolan, who was supported by Enerpac WA territory managers Andrew Marsh and Michael Allfrey.

Electronic gauges with digital readouts were used so that lifts could be monitored and recordered.

Enerpac RSM/RCS series low height cylinders feature maximum power-to-height ratios for confined space lifts in construction, infrastructure, machinery and mining applications. Often used in combination with V series needle valves to control cylinder speed during lifting and lowering, they feature baked enamel finishes for corrosion resistance, hard chrome-plated steel plungers and grooved plunger ends requiring no saddle. The RSM Flat-Jac cylinders used on the St Mary’s project feature mounting holes to permit easy fixturing.