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Best of both world ds

CONCTRETE

Hybrid concrete construction, using a mixture of in-situ concrete and precast elements for building structural frames, is seen as the next big thing.But will it hold fast? Paul Thompson asks the experts

LIKE IT or not concrete has been haemorrhaging market share to steel frame for years.The rate may

have slowed over the past couple of years but nonetheless it is still bleeding and something is needed to stem the flow.

Not a miracle cure but some kind of treatment that will help a weakened, yet still kicking sector back on its feet.

Charles Goodchild and Andrew Minson are two concrete structure specialists who think they have found the answer to the concrete lobby's prayers.Now all they have to do is spread the gospel.

Using a mixture of both cast in-situ concrete construction techniques and precast concrete for the structural frame may hardly seem revolutionary to most but the fact is that the notoriously conservative UK construction industry has been slow to see the benefits, according to Mr Goodchild, principle structural engineer at the Concrete Centre.

'The theory behind hybrid concrete construction is not new by any means but many have been reluctant to take it on in the UK because there has been little guidance on how to go about it, ' he says.

Sure enough in south-east Asia and Australia use of the in-situ/precast mixture is commonplace and Mr Minson, the Concrete Centre's head of structural engineering, is one who has first hand experience in using HCC.

'It is used a lot all over Australia. It's an everyday thing, ' he says in his waning Brisbane lilt.

Maybe, but try telling that to contractors in the UK who already have well-established work methods.

'That is exactly why we needed to carry out this work.' he says.'Within the best practice guidance there are case studies that will help contract teams through a project.'

But a significant shift in project management, away from the traditional style of contract, is also needed for HCC to be successful. For anyone to fully appreciate the benefits of marrying the two materials the specialist suppliers and contractors need to be involved much earlier on in the project timetable, as early as the design stage.

And that will see clients having to stump up cash much earlier in the process, which is not a trait they are renowned for.

'The key to the whole process is to have real rather than token input from specialist contractors and precast suppliers and for that they will have to be paid, ' says Mr Minson.

'Look at it from the clients point of view: if you only get a free day's advice from a specialist would you be prepared to commit your design team to it?'

Less adversarial forms of contract will prove a boon to the eventual take up of HCC though, according to Mr Minson.

Design and build, PFI and all things Latham and Egan are music to his ears.

'The rise in design and build will be great for all early input and all the partnering initiatives are positive for the uptake of HCC.The process will be made easier once more examples of its use are available, and there will be more thanks to the number of PFI projects under way, ' he says.

The main thrust for its introduction though is coming not from the clients themselves but from in-situ frame contractors, claims Mr Minson.

They want to see quicker erection times on site and see HCC as the perfect method for that.

But it is not just the more common use of precast concrete columns for the frame that Mr Goodchild and Mr Minson want to promote.They want designers and clients to realise the sense in using more precast concrete throughout a project.

If precast edge beams were specified they could be manufactured with anchorage blocks for post-tensioning the slab already cast in, saving both time and money on site.

'That is why it is essential to get all team members together early on so that the full advantages of using precast are realised, ' says Mr Minson.

'Sure you would save time on site using precast elements anyway but, if the project is thought through and planned properly, then those gains keep on multiplying.'

And the list of gains is a long one, says Mr Goodchild. From speed of construction to increased leasable space, improved health and safety to buildability, all trip off his tongue as easily as the alphabet.

'These types of buildings offer great value for their clients.They get all the bonuses of using precast - speed of construction, buildability - wrapped up with the inherent benefits of thermal efficiency, such as resistance to fire and flexibility that in-situ concrete gives them.'

He waxes lyrical about the advantages of final finish that precast concrete can give and is more than happy with concrete's current renaissance with architects and designers.

'There have been some fantastic examples of HCC already, the Toyota Headquarters in Epsom, for one, has been praised for the quality of its build and finish, ' says Mr Goodchild.

And Mr Minson is keen to point out that it is not just architecturally significant buildings that can benefit from using HCC but standard industrial units can also reap the rewards.

'It is not just for major projects. Standard, ordinary schemes can get a real boost from HCC.This is known technology.All we are doing is putting in place the mechanism that will allow it to be used more regularly.'

Pinching market share

JUST what is the likelihood that the latest incarnation of the concrete frame sector will fend off steel frame and pinch back some market share?

According to Charles Goodchild and Andrew Minson of the Concrete Centre you should put your cash on a surge of interest from all sectors in precast/in-situ hybrid techniques.

'If clients recognise the huge advantages of working with hybrid concrete construction and put in place the process to allow it to work properly then we will take market share from steel, ' says Mr Minson.

According to Mr Goodchild changes in working practices with greater emphasis on long-term supply relationships and framework agreements will help boost HCC methods.

'I think the penny has dropped between frame contractors and precast suppliers that they can work well together.HCC is already creating a buzz in the industry. It will be competitive and it will steal market share, ' he says.

HCC best practice

CHARLES Goodchild, principal structural engineer at the Concrete Centre and main author of the guidance document, has been researching the use of HCC for years.

The whole project is part of the Department for Trade and Industry's Partners in Innovation programme and Mr Goodchild has spent four years helping to draft the final Best Practice Guidance for Hybrid Concrete Construction document.

But the research stems back further and builds on work that was carried out a Salford University in the mid-1990s.

'There was some initial research done on HCC for the UK which found that its users were very positive about it.They thought it looked good and worked well but the research revealed there were still some question marks over its 'buildability', ' he says.

Loughborough University's Dr Jacqueline Glass helped move the Salford work on by carrying interviews with clients, designers, contractors and precast producers to help map out the whole construction process from inception to completion.

'From there we could see where the different sectors meet and how to achieve best practice for all concerned, ' says Mr Goodchild.

Initially 13 schemes were looked at but these were whittled down to four by Mr Goodchild and his team.These would act as the basis of the document and be presented as case studies.

The four - Ipswich Town Football Club North Stand; Toyota (GB) headquarters; West Car Park, West Quay, Southampton; and Whitefriars, Canterbury - were chosen both for their diversity and their 'ordinariness'.

'It has helped us produce a document that will be of benefit to all involved in specifying HCC, ' says Mr Goodchild.