The retail gap between road, rail and sea

A development in Aberdeen will fill a gap in the UK’s oil capital’s retail market but its confined site has meant complex negotiations and technical challenges. By Mark Alexander

Project:Union Square retail and leisure development
Client:Hammerson
Main contractor:Miller Construction
Total investment: 250 million
Contract duration: 104 weeks
Contract type: Guaranteed maximum price (GMP)
Piling subcontractor:Stent
Steelworks subcontractor:Severfield Reeve

Scotland’s third largest city is also its closest to the valuable reserves of black gold under the North Sea. Aberdeen ’s location may be remote, but it has certainly brought it wealth.

As its economy has flourished, Aberdeen has emerged as one of the wealthiest municipalities in the UK. But while Aberdeen has enjoyed the riches of the oil industry, its facilities have often been found wanting.

According to real estate developer Hammerson, the retail market gap in the city is worth 936 million. With typical household incomes exceeding the UK average by 58 per cent, it’s easy to see why the company has decided to invest 250 million in a 700,000 sq ft retail-led regeneration development in the city’s centre.

“In simple terms, the ratio of cash in Aberdeen and the number of ABC1 category consumers compared to the equivalent level of quality shopping available is poor,” says Hammerson’s project manager, Nick Fey. “We’ve identified a gap in the retail market, hence we’re building a shopping centre.”

More than a mall

To describe Union Square simply as a shopping centre would be to simplify matters. The 56 retail units, up to 12 catering units, 10-screen cinema and 203-bedroom hotel ensure its facilities will be extensive.

But while there are architectural flourishes that link the retail and leisure – the main atrium entrance will be striking – they aren’t going to make the development exceptional.

What will is the number of transport modes that converge on the site, seemingly from all directions. Aberdeen’s main railway and bus stations occupy key parts, while the city’s harbour is a stone’s throw away.

The site is also bordered by Guild Street to the north and Market Street to the east – two of Aberdeen’s busiest thoroughfares. If ever a site deserved to be called a transport hub, this is it.

“I don’t think I’ve ever worked between a live bus station, a railway station and a harbour,” says main contractor Miller Construction’s operation’s director, Richard Gallagher.

“This is a site where you can look at boats, trains and cars all at the same time.”

The concentration of transport options is certainly being pushed as a key selling point to attract potential tenants to Union Square, but it also presented a series of construction challenges that Miller and Hammerson had to overcome.

Network connections

Although the origins of Union Square can be traced back to 1988, it wasn’t until 2006 that Hammerson finally secured ownership of the scheme. Previously, much of the site had belonged to Network Rail which resulted in a drawn-out agreement process prior to construction, as Mr Fey explains.

“Parts of the site were under the ownership of Network Rail so there was a myriad of agreements we had to go through to get to the point where everyone was happy,” he says.

This included a 25 million contract of enabling works that involved creating two new goods yards, and upgrading Network Rail’s infrastructure to the organisation’s exactingstandards.

The extent of these appeasement measures even extended to the colour of the PPE which, rather than being yellow, was orange to match Network Rail’s policy.

Site management

Since the 528,000 sq ft Union Square site was made up of a number of land parcels, not all of them were made available when work started on site in November 2006. A sequenced approach was needed to progress the job, starting with the new bus station being built in the north east corner, which would replace the existing one found in a more central plot that would become the shopping centre’s main entrance.

“Under normal circumstances you’d be able to plan because the site would already exist,” says Mr Gallagher. “This is a compilation of sites where we had to finish one bit to get to another, but we didn’t always get things when we planned – some things slipped while
others came forward. So we had to adopt a flexible approach to the programming of the job.”

This piecemeal approach also meant Miller had to react to unforeseen issues that arose when the land eventually became available. “When the bus station moved out, we had to demolish the old premises and that’s when we found some asbestos,” says Mr Gallagher. “Because it was a live building site, there was a limit to how much you could prepare before the demolition.”

The team also discovered the building was resting on a set of platforms which also had to be excavated.

Action stations

One of the most complex issues was working alongside Aberdeen’s railway station which will ultimately become part of the final shopping centre. The station has an A-listed status (that roughly equates to a Grade 1 ranking). The station would form an integral component of the shopping centre by forming one side of an atrium entrance.

Initial work included creating new offices and a new travel centre alongside the sandstone fa硤e, which was to be incorporated into the plans to create an atrium entrance to the centre. Public access and safety was maintained throughout by a series of covered walkways.

Unlike the rest of the rest of the site where pre-cast driven piles were used, piling contractor Stent used continuous flight auger piling, to address Network Rail’s concerns that piling would worry the public.

“We used a CFA piling system because it would have been more alarming if we had hammered,” Mr Gallagher explains.

“We had to go through a series of approvals with Network Rail in terms of the methodology we were going to use, although interestingly I don’t think they even noticed when the piling started. There was someone working on the other side of the wall where the piling rig was and he didn’t know it was working.”

Similar efforts to reduce disturbance were made during the construction of the eight-storey hotel which sits on top of two retail floors on the north edge to the centre.

“The hotel’s location, up tight against the bus station, a live railway station and Guild Street, meant building it was technically quite challenging,” says Mr Fey.

“Basically Miller had to erect it from inside the site without interfering with the traffic and pedestrians.”

And if that wasn’t difficult enough, they did it all without the luxury of a tower crane.

“Tower cranes are much higher and Network Rail have requirement that if a cataclysmic collapse occurred, the crane wouldn’t fall onto live rails. By using mobile cranes it wasn’t a concern,” says Gallagher.

“We had to be mindful at all times of what Network Rail’s view might be. We developed that kind of mentality to make things easier for ourselves.”

While the project is currently at various stages of completion with cladding work taking place and M&E starting, Union Square is due to complete in October.

What crunch?

Aberdeen’s history may be inextricably linked to the North Sea but its future may lie elsewhere.

Alongside the 250 million investment being made by Hammerson, others are keen to cash in on the Granite City’s bright future. Donald Trump, for example, is building a 1 billion golf course, just north of the city, while a 115 million golf development at Blairs College is
taking place to the west.

The University of Aberdeen recently unveiled plans for a 28 million sports centre and a 57 million library, while Peacock Visual Arts is planning a 13 million contemporary arts centre.

The Wood Group building its new 55 million headquarters there.

With all this development, many have called Aberdeen the city the credit crunch forgot.

Steely entrance

The steelworks that form the centre’s main north and south entrances will be a key architectural component of the centre.

As well as including a large atrium roof, the north entrance will also encompass the original sandstone facade of the railway station – the only such building in the city.

In addition to providing access to the shopping centre from the railway station, the facade and the adjoining steelwork will also link the past with the present.

“One of the most interesting aspects of the job is the erection of the north atrium steelworks,” says main contractor Miller Construction’s operation’s director, Richard Gallagher.

“Because it’s a cantilever structure that has to be safe throughout its erection, there are a number of temporarily erected structures we had to put up to hold it in place. It’s essentially two large girders that cross each other but it’s going to be a big feature of the scheme.”

The highest point of the atrium’s timber curved soffit reaches over 15 m. The atrium itself is 29 m wide and 40 m long.

Along with four columns, more than 250 tonnes of steel were required during its construction.

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