It is the sheer scale and speed of the construction achievement at Scotland's biggest shopping and leisure centre that impresses. In slightly more than two years, the #230m Braehead development has bulldozed new life across a 200-acre site. Where once there was dereliction and waste, now stands landscaped economic vitality.

At its centre is the huge steel, glass and aluminium structure housing the integrated shopping and leisure facilities. Around it are retail and business parks, the

maritime heritage centre and

picnic and walkway areas along the River Clyde.

From a distance the impression is gained of a shiny new kid on the block, amid the cranes and the shipyards, boldly elbowing out room for himself at the table

of commercial and maritime


Harry Downie, project director for Bovis on a design, manage and construct contract for all but the retail park area, says: ''I am immensely proud to have been part of all this. It is the biggest project of this nature Bovis

Scotland has ever carried out, and I don't see anything quite of this size coming forward again in the foreseeable future.

''The dimensions of the shopping/leisure centre and the timescale involved represent a considerable achievement for

the entire team, which includes ourselves, project managers MPM Adams, the Building Design

Partnership (architects), structural engineers Beattie Watkinson, Cyril Sweett (quantity surveyors), Roberts and Partners (building services engineers), sub-contractors, and local authority planning and building control officials.''

There are many unusual features about the Braehead development. If the buildings are set in concrete, the plans never could be. Buildings like this evolve as they are constructed and the flexible nature of the contract is designed to accommodate this.

So there is considerable satisfaction that the deadline for opening day last week was achieved despite 450 design changes during the course of the work, including a major alteration involving lifting the curling rink from the ground to the first floor to enable more retail provision underneath. In fact, the entire leisure complex expanded dramatically in scope over the period, as the recreat-ional opportunities of the three ice and general entertainment areas was appreciated.

Another unusual element was that the builders had to deal with two planning authorities - the site straddles the boundary between Glasgow and Renfrew. Glasgow was given the lead role in building control but both authorities were closely involved in the detail of planning approval.

Bovis says the co-operation and help afforded by both authorities significantly assisted the entire programme.

The magnitude of the shopping and leisure centre is what makes many elements of the job ''diff-erent''. It is staggering to think that the entire steel frame building - with 102,000sq m of concrete floor space - is suspended above the ground, built on what the layman might describe as stilts, although they are not visible.

Before construction could start, many tonnes of earth and topsoil had to be removed to rid the area of old industrial contaminants. The ground then had to be refilled. Time was of the essence.

To avoid compacting and

waiting for settlement, Gilmour suggested the enormous ground floor concrete slab could be suspended off the ground on concrete piles driven into the earth to a

distance of between 10 and 20 metres. Not an unusual cons-

truction technique, but the proportions are exceptional. A total of 11,500 foundation piles were employed.

Close to the river, the high water table had to be countered to prevent water penetration. Matt Collins, Bovis's assistant project manager, says the ground floor slab was covered in self-sealing, clay-like, waterproofing material, which has the ability to heal itself even if damaged.

Joe Public may be interested to know that if the shopping and leisure facilities don't make the earth move, then the building might, just a little.

The sophisticated techniques employed to calculate and accommodate the natural movements of a steel-framed building of this size are fascinating.

There is a built-in tolerance for expansion or contraction of up to 30mm in either direction, relat-ively speaking a fair movement, but then everything is on a grand scale at Braehead.

Structural movement and field limitation joints have been introduced at a number of locations. Walk along the mall and you might come across the occasional metal plate, covering the joints where the movement takes place as the building heats and cools down. Even the handrails and other finishes are designed accordingly, and the tiles which make up the Terrazzo flooring are on the small side so that cracks go round rather than through them.

The statistics from the site make interesting reading: 13,500 tonnes of structural steel was required, the metal roof areas stretch to 46,492sq m and glazed roofing extends to 5650 sq m. There was 170,000sq m of landscaping, and 2000 new trees were planted.

Collins says: ''What we had here were challenges of scale. I have to say that we would look at this as being one of the most

satisfying jobs we have ever been involved with.''