Contractors need to be able to count on reliable and durable construction equipment when building large structures – they know that technical failure and downtime can lead to delays and higher costs.
From dams on the River Nile to new sports stadiums in the Amazon, equipment manufacturers and contractors are working to ensure large projects stay on schedule.
As well as general earthmoving and lifting machinery, specialised construction equipment models are available to tackle big projects. Falsework and formwork manufacturer Doka, for instance, has launched new specialised formwork just for dam construction, while XCMG teamed up with Chinese petrochemical company Sinopec to develop a huge 4,000 tonne capacity crawler crane for extreme lifting jobs.
The XGC88000 crane made its debut lift at the Wanhua Industrial Park in Yantai, China, where it was tasked with hoisting a 118 m tall, 1,680 tonne propylene production tower into place. The crane’s 108 m boom and 33 m fixed jib were used in a 30 m operating radius.
Developing the machine is one thing, but delivering it onto a remote construction site is another question entirely. Co-ordinating the movement of materials and equipment around a large structure jobsite can be a major challenge, and a highly organised approach is crucial to keep things moving efficiently.
In South America, for instance, equipment from Terex and its sister brand Genie is supporting construction of the final stages of the 45,000 seat Arena da Amazonia Stadium in Manaus, the capital of the Brazilian state of Amazônia.
Set to host four matches during next year’s FIFA World Cup, the stadium is being built by a trio of contractors – Andrade Guitierrez, ENTEC, and Tomiasi – and was designed by GMP Architekten.
The stadium’s most striking feature is its self-supporting roof, construction of which is currently underway. Made from over 200 pieces of steel and weighing over 6670 tons (6500 tonnes), the roof structure will consist of mutually supporting cantilevers with steel hollow core girders. The largest individual components are 22 m long and weigh 30 tons (27 tonnes).
A fleet of Terex all-terrain cranes, previously used to place pre-cast elements during the initial construction phases, are lifting individual parts of the roof to form sub-assemblies, which in turn will be lifted and put into place with a Terex CC 2400-1 crawler crane. Finally, construction workers weld them together with the help of Genie Z 80/60 boom lists for access. Construction is scheduled for completion at the end of the year.
Once the parts arrive at the site, work is co-ordinated almost like an assembly line, according to Thiago Bezerra, construction and equipment engineer at contractor Andrade Guitierrez.
“The Genie booms were perfect for this project. The structures were very complex, as you and the ample freedom of movement of the Genie Z boom allowed us to work efficiently and safely. The technological advance of construction machines like these allow the increasingly complex and innovative to happen,” he said.
Similarly, RMD Kwikform needed to pool its resources in order to source equipment quickly to support the construction of a new water infrastructure project in Doha, Qatar.
Qatar Building Company (QBC) used a range of formwork and shoring equipment from RMD Kwikform to cast slabs on four large concrete reservoirs. Each circular reservoir is 8 m high with a diameter of 125 m, and the programme allowed just four months for the slab construction.
RMD Kwikform’s Alshor Plus and Rapidshor shoring tables were supplied, together with Superslim Soldiers and GTX timber beam supported formwork. The company sourced the formwork from across its Middle East businesses.
A QBC spokesperson said, “For this project it was all about time and scale. We had four months to get the job done and we knew we needed to source a significant amount of equipment, get it to site swiftly, erect it and get it offsite efficiently, once the job was completed.
“Having worked with RMD Kwikform for over five years and more recently on a similar water project, we knew they could design a solution to meet our needs. Having previously used Alshor Plus in particular, we knew our site staff would also be familiar with the product and therefore faster in the erection and dismantling processes.”
The spokesperson said that by erecting Alshor Plus and Rapidshor into 7.5 m high table sets, they had reduced the need for erection and dismantling, cutting up to -50% off the time from one pour to the next. In total, 550 tables were used to construct the main soffit slab for the project.
Izzet Ataol, sales manager for RMD Kwikform said the main challenge was the huge amount of equipment needed for the job. “Logistically we had to work very quickly to co-ordinate the delivery of equipment. We then liaised with the QBC team to ensure we delivered the right amount of equipment to site, when it was needed.”
Access lift and hoist manufacturer Geda, meanwhile, is supporting construction of another large structure – the US$ 18.5 billion Stantos liquefied natural gas (LNG) plant in Queensland, Australia.
The project aims to convert gas extracted from coal seams into LNG and is a joint venture between Santos (30%), Petronas (27.5%) and Kogas (15%). Contractor Bechtel has been tasked with building the LNG tanks on Curtis Island, and drafted in two Geda PH 2032 650 single hoists to help with access on the project.
Each hoist boasts a 1.55 m by 3.20 m platform that has a capacity of 2,000 kg – this means a maximum of 25 people and/or a range of construction materials. The hoists feature overload protection as standard.
Geda said 260 individual steel components are being delivered to Curtis Island from all over the world to build the LNG tanks. It said construction work was on schedule and the first LNG is on course to be exported worldwide in 2014. By 2015, the plant is expected to be operating at the maximum production level.
Meanwhile, falsework and formwork manufacturer Meva said calls for better worker safety on large structures from international contractors are increasing. It said that while regulations differ from country to country, fall protection is common
“Often however, makeshift arrangements are pieced together on the site from whatever material is lying around. This method proves penny-wise but pound-foolish in contrast to all-in-one, tested safety systems, especially when costs for consumables and tedious assembly are compared,” the company said.
Meva said its SecuritBasic equipment answered demand for a simple, cost-effective worker safety system. It is a modular system with integrated non-slip working platform as well as side, front and guard railings, access hatch with ladder, inside corner and filler platforms.
The system was put to use by contractor Erne in Switzerland. The company required safety equipment that would meet SUVA (the Swiss national occupational health and safety authority) standards for a CHF 500 million (US$ 553 million) project to build new production facilities for pharmaceutical group in Stein.
Meva’s Mammut 350 panels (2.5 m wide, 3.5 m high) were stacked up in fours to accomodate the 14 m pours required to build the factory walls. Meva said SecuritBasic could be assembled on the ground and moved as a complete unit together with the formwork in a single crane. It said a lifting arm and standard crane hook were all that was required to move the SecuritBasic system, saving time and keeping worklflow smooth.
Machine control technology can also be useful when it comes to co-ordinating equipment at work on large projects. The South-North water transfer canal development in northern China certainly falls into this category – it is one of the largest infrastructure projects currently underway in the country.
The project began in 2002 and is due to be completed in 2050, with the running cost standing at US$ 27 billion in 2012. After completion, up to around 45 billion m3 of water are to be diverted annually through the new canals, bringing water from the south to Beijing in the North.
The construction companies involved with building the 1,200 km middle section are Sinohydro Bureau 11 and Military Police Hydroelectricity, and have equipped their excavators with Moba’s Xsite Link system to monitor and measure earthworks.
“When constructing the canals, the correct slope must be maintained as early as in the earthwork stage, both when working on the river bed and on the embankments. For this reason, we use the Link excavator system – with it, you can see exactly how deep and at which incline work is done,” said Zhang Gong, section chief of Sinohydro Bureau 11’s equipment department.
The sensors of the excavator system are attached to the bucket, stick, boom and chassis and record the respective incline angle. They calculate the excavation depth, the incline and the range of the bucket.
“With the system, I can help new excavator operators become qualified employees without a long training period”, Mr Gong continued. “We work faster and much more productively. In the same amount of time, we can do about +30% more work.”
Together with co-ordinating the delivery and maintenance of materials and equipment, safety is clearly another crucial aspect for any contractor to consider when building large structures. It will be interesting to see how contractors and manufacturers continue to work together to keep work progressing efficiently and safely in the future. SOURCE: KHL