Latest technology for building large structures

The complexity of large-scale construction projects can pose some unique challenges, but it is crucial for contractors to stay on top of safety, costs and the programme while grappling with these issues.
The development of building information modelling (BIM) is one tool being used to manage the construction process, and it is increasingly trickling down to smaller projects from the large civil and oil & gas sectors where it was pioneered.

According to a survey of infrastructure experts commissioned by law firm Pinsent Mason, two thirds of respondents said the key benefits of using BIM were improvement in the design process (63%), risk mitigation and health and safety monitoring (57%), while 47% believed that its usage brought greater transparency for clients.

Rob Charlton, managing director of architectural services company Space, believed computer modelling had been hugely influential for large-scale construction development.
He said, “BIM is being adopted increasingly across the globe. Initially its adoption was confined to particular sectors or geographies, but it is now universal to a greater or lesser extent.”

Among US companies adopting advanced 3D modelling for construction is Rafael Vinoly Architects, whose latest
US$ 1.2 billion project, the super-slim 432 Park Avenue Tower in New York, is nearing completion.

The 424 m, 104 luxury apartment block has been billed as the largest residential tower in the Western hemisphere and has attracted global headlines over its property prices of up to
US$ 95 million for its sky-high penthouse.

Building contractor Roger and Sons teamed with Doka formwork to deliver the distinctive building, which also used latest GPS-based vertical alignment systems from Leica to ensure the accuracy of its construction at great height.

The main core of the building features an advanced automated formwork system from Doka. One of its major cost-saving elements is the fact that climbing on the exterior walls has not required a crane. The Xclimb 60 automatic climbing formwork transports the steel formwork custom-made to clients’ specifications.

The formwork includes a total of five levels dedicated to different tasks from pouring to hydraulic lifting and installation.
Another eye-catching construction venture that has made extensive use of BIM design is the UK’s Crossrail project – which is believed to be a first for a nationally significant infrastructure undertaking.

The UK£ 15 billion (US$ 24 billion), 100 km route connecting Heathrow in West London through to South East London is expected to increase the city’s rail capacity by 10%.

As the only element of this huge infrastructure project to run directly beneath the River Thames to link-up with the existing underground network, the UK£ 200 million (US$ 320 million) North Woolwich tunnel has encountered a number of technical challenges during its construction.

With some 300 construction staff on-site at any one time, the joint venture between Hochtief and Murphy spans 2.5 km in length.

This required the efforts of two 7.1 m diameter Herrenknecht tunnel boring machines (TBMs) operated by crews of 20 workers on shift-patterns 24-7 for nearly 18 months from May 2012.
Project manager Neil Murray explained that delivering it safely on time and on budget were the key elements to the scheme, describing completion of the tunnelling work as a “key milestone.”

He said, “We are delighted with the way the two tunnel portals have been formed at North Woolwich and Plumstead. We’re also extremely pleased with the tunnelling – they are finished to a very high quality and it has been done safely.”

The issue of following strict health and safety guidelines has been of particular importance. Everything from maintaining an exact log detailing how many people are working below and above ground at any one time, to ensuring construction workers are equipped with advanced breathing apparatus in the event of a gas leak.

In terms of the tunnelling itself, the TBMs– known as Sophia and Mary (named after 19th century engineer Isambard Kingdom Brunel’s wife and mother), have been built to cope with the testing geological conditions below the River Thames.

Clearly, using such immense machines requires considerable expertise. What were the biggest challenges?

The project manager added, “The ground strata varied depending on the depth and location - combination of sand and gravels and as we got deeper, we entered chalk – when you go from one sub-strata to the next, that’s where the trickiest part of the operation is, but we tackled this head on and we were successful getting through each layer to the finish.”

Hong Kong

One region that has seen a particularly steep level of growth for major construction projects has been Hong Kong.
As Noel Kennedy, country director of RMD Kwikform, enthused, the expansion of the construction sector had prompted the company to review its strategies and approaches to its major projects.

These include the Kowloon rail terminus and the UK£ 6.5 billion (US$ 10.47 billion) Hong Kong - Zhuhai - Macau Bridge, which was first mooted in the early 1980s and is finally coming to fruition.
It will include a 12 km link road, boundary crossing facilities for government officials and their respective departments, in addition to further infrastructure development.

At 29 km in length, the bridge is one of the largest schemes of its kind in the world and is expected to foster greater economic ties between Hong Kong and China. Work began in 2009 and its sheer scale has required some innovative approaches.

As part of the overall pier formwork solution, RMD Kwikform engineers designed integrated access platforms to support the erection teams whilst they were working on the complex linkage sections of the formwork.

These included void spaces and protruding sections, each created at different angles to allow for the precast bridge segments to be mounted to the piers. It is due for completion in 2016.

Mr Kennedy said, “In practical terms, this has highlighted the importance of strong links between our on-the-ground support teams and our solution design engineers. For example, the main bridge and the Boundary Crossing Facility section, currently part way through construction, required formwork and shoring solutions for both land and marine structures.

“These consisted of designs for numerous land piers and portal beams, with specialist pier forms for the marine sections. With a large amount of standard equipment and bespoke elements required for the project, we engaged with a number of local suppliers to fast track the fabrication of special elements.

Bosphorus Bridge

Another significant bridge currently under construction is the Yavuz Sultan Selim Bridge in Turkey, which will provide a third crossing over the Bosphorus for the heavily congested city of Istanbul, Turkey. The IC Ictas and Astaldi consortium behind the US$ 2.3 billion project signed an initial financing deal for the scheme last autumn, with a total of seven banks providing the capital.

The 59 m wide bridge will carry eight traffic lanes and two railway tracks over a central span of 1,408 m and will form part of the new 260 km North Marmara Motorway.

Formwork is being supplied by Peri, which says the ambitious project will include the tallest concrete bridge pier in the world. The suspension bridge will feature two A-shaped pylons around 330 m in height. The main formwork for this will be Peri’s ACS self-climbing system and Vario GT 24 girder wall formwork.

For the inclined surfaces of the A-shaped pylon legs, the adjustable version of the ACS V self-climbing formwork is being used, which can be adapted to suit the sloping sides of the pylons. The ACS climbing units also include sheet cladding, which offers fall protection as well as additional wind and weather protection for workers.

Udinese

Tackling major renovations to football stadium in Udine, Italy has proved a rewarding task for formwork maker Pilosio. It has been involved in the upgrade of the Stadio Friuli multi-purpose stadium that includes gymnastics, athletics, and martial arts facilities and is also home to the Udinese Calcio football team.

The project involves remodelling the present seating arrangement of 41,652 capacity, which has required a complete rebuild of its north and south stands. Its west stand, which was already covered, will be refurbished as part of the works that have included Pilosio providing P300 formwork for casting foundations and walls, plus a modular system for scaffolding and service stairs.

Meanwhile, Alsina has demonstrated its flexibility in taking on a particularly unusual large-scale construction task. It is involved in building an internal security forces camp in Doha, Qatar, which has posed a number of challenges – not least working in the extreme heat of the country.

The company has supplied its Mecanoconcept formwork for the first time in the country, having successfully used it within Spain for the past 40 years.

According to its developers, the system’s use has boosted productivity. Mechanical Mecanoconcept formwork is said by the company to be simple to work with. It allows recovery of up to 80% of the formwork equipment used within three days of concreting, so that it can be reused for shuttering higher slabs.

Hydroelectric scheme

Hydroelectric power schemes are proving a growing phenomenon around the world and the 1,285 MW Xayaburi dam and power plant in northern Laos is among the most notable.

A total of 19 Potain tower cranes have been employed on the site, operating 24/7 on the eight-year project, which will create an 820 m long dam across the Mekong River.

Their primary task is to place roller compacted concrete at a rate of 250 m3 per hour. Handling much of this work are two Potain MD 1600s.

These giant 64 tonne capacity tower cranes are fitted with Potain’s top-belt concrete placing system, which combines the benefits of a powerful crane with a concrete conveyor belt, which extends 25 m beyond the jib end, enabling each crane to pour up to 600 tonnes of concrete per hour at a radius of up to 105 m.

The concrete placing system was one of the main reasons Potain cranes were chosen for the demanding project.Manitowoc – Potain’s owner – and partner Nippon Conveyor created the solution, combining Nippon’s belt conveyor system and the high capacity Potain MD cranes.

The dam is owned by Xayaburi Power Company, and is due to enter service in 2019.

Meanwhile sustainability has been a core feature of the One Airport Square development in Accra, Ghana, which is due to be completed this month.

According to its development team, Laurus Development Partners, the site is the country to have obtained the highest level of environmental certification for its construction and operating standards.

These have included the incorporation of natural ventilation and light, to minimise energy consumption, and enable rainwater harvesting. Overall these sustainable features will reportedly result in up to 40% reduction in energy usage.

According to the company, logistical challenges were some of the most testing encountered during the construction phase. Its design team was based in two separate locations, the UK and Italy, with the contractor based in Ghana.
Materials were sourced and, in some cases, fabricated at different

locations around the world, with the majority of the bespoke formwork having come from South Africa and Italy. Ensuring effective and timely communication across each stakeholder spectrum has been a vital element of the project’s success.

With the flow of major multi-billion dollar construction projects continuing to enter development around the world, it is clear that breakthroughs in technology are helping deliver these schemes faster, larger and with higher-specifications than ever before.