Bridging the gap in African infrastructure

Leading formwork manufacturers have secured some impressive contracts in Africa, as the continent’s transport infrastructure continues to improve at a rapid pace. Meanwhile, other bridgework equipment companies are also seeing their products in demand in Africa, as well as North America and Australia.
Road Structures / December 20, 2013
Doka Bouregreg Bridge  formwork SKE100
The Doka technicians planned an individual solution for the Bouregreg Bridge, based on Automatic climbing formwork SKE100, for each casting section
Leading formwork manufacturers have secured some impressive contracts in Africa, as the continent’s transport infrastructure continues to improve at a rapid pace. Meanwhile, other bridgework equipment companies are also seeing their products in demand in Africa, as well as North America and Australia. Guy Woodford reports

The centrepiece of an important new motorway bypass near Morocco’s capital Rabat, the Bouregreg Bridge is one of the world’s most spectacular current bridge construction projects. Due to be completed in August 2014, the 952m long cable-stayed structure symbolises the modernisation of Morocco’s infrastructure. Architecturally, it stands out for its two pylons – one 197m, the other 185m tall. Their artistic shape is also presenting some tough formwork design challenges. The solution devised by 203 Doka for joint venture contractors 5718 MBEC-2487 COVEC is based on the firm’s Automatic climbing formwork SKE100 system.

The Span between the two oval main piers, through which the deck of the eye-catching bridge will pass, is 376m long. The bridge pylons are each made up of four curved pillars, lending this massive structure a stylish and open aspect. Visually, the bridge deck separates the upward-tapering main piers half-way up, taking the roadway through between them. “For the Doka formwork experts, this meant uniting several different sectors, with differing layouts, into a single work of formwork planning”, said Daniel Maderthaner of Doka Engineering.

The SKE100-based Doka solution for the Bouregreg Bridge requires only minor modifications to the system, and makes efficient use of the equipment. Despite the great versatility of the climbing system and the fact that it allows rearward inclination, custom components and telescopic platforms were developed and fabricated to Deal efficiently with the continuous changes in inclination.

Combining this climbing system with versatile ‘Large-area formwork Top 50’ is said by Doka to have made for an efficient overall solution. The basic elements of the formwork stay the same in every casting section. A very few modifications to the construction are all it takes to manage complicated layouts.

The bridge pylons are each being formed with 40 units of Automatic climbing formwork SKE100 and around 220 elements of the Large-area formwork Top 50 system. MBEC-COVEC was looking for a system with which the desired construction progress could be achieved quickly, even in windy conditions. The 45 casting sections, each up to 4m high, are being completed in weekly cycles in some cases.

The high-performing crane-jumped Climbing formwork MF240 and Large-area formwork Top 50 are being used on the five piers in the foreland zone. This solution was also used on the concrete plinths for the pylons.
The formwork planning for this prestige project in Morocco was carried out in collaboration with experts from Doka headquarters in Amstetten, Austria. A team comprising staff from the Highrise and Pylons Competence Centre, from Doka Engineering in Morocco and from the Statics Department delivered detailed plans to make the challenging architectural concept workable in practice. Doka formwork instructors were on-site to help with correct assembly of the Top 50 and SKE100 elements, ensuring that the systems were assembled and erected at speed.

With the help of 3D planning, 298 PERI engineers have devised a project solution for the new Trans-Rhumel Bridge in Constantine, Algeria based on mainly rentable system components. The individually designed and flexibly adaptable superstructure formwork with intelligent cycle sequence is said to have saved valuable construction time.

The 750m long cable-stayed bridge – supported by two 130m high pylons and six bridge piers – is an integral part of a 6km long urban motorway project. This has helped to reduce traffic congestion in Constantine city centre which features a number of historical bridge structures. Four lanes, with sidewalks on both sides, Cross the gorge-like Rhumel Valley at a height of 80m. The single-cell hollow box Cross-section features an extraordinary width of almost 30m. For its realisation, a team of Algerian, Portuguese and German PERI engineers working in close collaboration developed efficient formwork and scaffolding solutions.

The systems used ranged from TRIO panel formwork for the abutments and VST heavy-duty shoring towers from the VARIOKIT engineering construction kit through to PERI UP working scaffold for the assembly of the cable-stays on the bridge pylons.
One of the project’s biggest challenges was said to be the bridge superstructure above the pier heads. The complicated geometry with differing Cross-section widths as well as varying longitudinal and transverse inclinations resulted in complex intersections. For this, PERI developed a 3D-based, technical concept which was said to be easy to understand and implement without any problems on the jobsite. The use of rentable system components, in connection with project-specific steel components, proved, said PERI, to be the most cost-effective option.

7163 Pilosio has won an order worth around US$2.39 million with fellow Italian firm CMC of Ravenna to provide its formwork systems to aid the construction of a key motorway junction in the South African port city of Durban, Kwazulu-Natal - the N2-M41 Mount Edgecombe Interchange. 

More than two thirds of Pilosio’s equipment for the works will be tailor-made and deployed in the creation of two imposing viaducts through the ‘casting’ system, thereby avoiding any interference with the traffic below. One of the viaducts will be 26m high by 947m long – making it the longest in South Africa. The other will be a still impressive size of 18m by 443m. The entire CMC construction project is valued at $111.06 million.

Pilosio will supply 200m² of P300 formwork for foundations and trusses, 500m² of special steel formwork divided into five sets for the construction of the viaducts' pile shafts, an additional 350m² of special steel formwork made up of three sets for the construction of the pier caps, two sets of Maximix model formwork and some custom-made products. Additionally, the Omnimode shoring system with customised solutions will be used for the creation of the suspended work platforms to be used in the installation phase of the roadway ashlars. 

The tailor-made elements of the Pilosio systems supplied to CMC will be required for the constructions of the piles, the pier caps and the base of the roadway. Pilosio said its technical office produced a “swift and highly qualified” response to the various critical areas of the construction site, with the emphasis on rapid supply times, good coordination with the various organisations involved in the project (especially the firm VLC for the roadway ashlar casting technology), and designing a formwork system for the piles that could be adapted to two different sizes and for the roadways of the viaducts, making best use of installation technology with buttresses. The motorway interchange to be constructed by CMC will also include junction works such as slip roads and underpasses that will mostly be constructed with Pilosio’s equipment.  

Winning this contract is said to be only the first part of Pilosio’s wider strategy in the African continent. A company spokesperson added, “South Africa is the perfect hub for serving all the neighbouring sub-Saharan countries, many of which have some of the highest growth rates in the world. The CMC commission marks an important step forward for Pilosio in the company’s design expertise, given the technical complexity of the structures constructed ad hoc for the client.”

Barin has strengthened its presence in the Australian bridge inspection unit market by delivering its new AB 10.5 COMBI unit to Lincoln Hire based in Darra, Queensland.
Lincoln Hire is among the biggest rental companies in Australia and the country’s sole distributor of 1481 Barin inspection units.

Fitted with a bucket that can be launched from the right and left side of the vehicle, the AB 10.5 COMBI is due to be put to work on the railways network in Western Australia.

Barin says the standard three-axle 759 Scania truck which mounts the equipment is fitted with railway axles to switch the unit between railway and road-based bridge inspections. When the AB 10.5 COMBI is configured for road usage, the truck's suspension is locked to ensure stability to the unit.

The unit boom’s launch does not take place in a horizontal Plan, preventing interference during railway work with the aerial electric line up to 4.5m.

The railway axles are fitted with a self-propelling and self-steering hydrostatic device, allowing the unit to move on the railway at different speeds, depending on the application.

There are many safety devices installed on the AB 10.5 COMBI. These include thermic protection of the electric circuit, an interlocking device which prevents simultaneous manoeuvres from the turret and main platform control panels, an inclinometer system which arrests the translation manoeuvre during work in Case the unit reaches critical slopes of +/- 2% longitudinal and transversal on either the road or railway-based applications. The AB 10.5 also has a device that allows vehicle movements to be controlled from the cabin, if the platform is not in a folded position.

For road bridge applications, the AB 10.5 unit has a maximum horizontal underbridge reach of 10.5m, an overhead reach of up to 14m, a maximum underbridge vertical depth of 14m, and a 3.8m limit for overcoming lateral barriers.

For railway applications, the unit has a 10.5m maximum horizontal underbridge reach, a 13.3M overhead reach, a vertical depth underbridge of 13.5m, and can overcome lateral barriers up to 3.8m.

The Cascadia fault line sits below hundreds of cities, stretching from Northern Vancouver Island in Canada to Northern California in the U.S. Experts predict the next major earthquake caused by the fault could register 9.0 or greater on the Richter scale and could happen tomorrow or in 200 years.  To prepare, cities along the fault line are upgrading roads and bridges to handle such an event, and in many cases concrete removal by the way of mechanical hammers is necessary.
Concrete removal is a major concern on bridges, where vibrations from equipment like jackhammers could cause inadvertent damage to surrounding concrete and affect the integrity of the structure, but some cities are finding other, better ways to do the job.

The Granville Street Bridge in Vancouver, British Columbia is one example where contractors are using different tools. The bridge is currently undergoing upgrades including installation of new seismic isolation bearings and expansion joints. It’s one of the largest bridges in the city with eight lanes of traffic and a Span of 731.5m. When awarding the contract for upgrades to 6821 Graham Construction and Engineering, Vancouver City Commission specified the use of only one type of mechanical hammer for the job – a Brokk remote-controlled demolition robot.

Graham turned to Cheeseman’s Concrete Removal. Cheeseman’s is an all Brokk company, maintaining three models in its fleet and using them every day of the week. For the Granville Bridge, Cheeseman’s is using the compact Brokk 50 – which is only 58.42cm wide by 93.98cm tall – with a hammer attachment to remove the concrete around expansion joints.

Graham said it specifically chose the Brokk machine because it could remove the concrete with little vibration, as strong vibrations, like those created by jackhammer, cause micro-cracks in surrounding concrete. Over time these cracks grow and weaken the structure, which could lead to detrimental damage. Also, because the Brokk operates with less vibration and bouncing than a jackhammer it is more precise, allowing Cheeseman to excavate without damaging existing rebar. The hammer can also be placed at any angle necessary to excavate with minimal damage to surrounding concrete.

In addition to minimising damage to bridges, the machine also increases worker safety. Operators holding jackhammers absorb the vibrations from the machine, and over time they can suffer from repetitive strain injuries, disabling numbness, tingling and pain in hands and arms.

Prolonged exposure can even cause carpal tunnel syndrome or nerve damage. By comparison, users operate Brokk’s demolition robot with a remote control, eliminating the risk of these types of injuries altogether. The operator also can stand a safe distance from the demolition work, while maintaining a clear view. 

It might not be this year, or years from now, but the threat of Mother Nature unleashing the ‘big’ earthquake on the Cascadia fault is real. Municipalities like Vancouver are preparing, but when armed with the wrong tools they can create hazards that could be just as disastrous. Brokk says that by turning bridge projects into ‘Brokk jobs’ –as Cheeseman’s did on the Granville Street Bridge – workers will remain safe and bridges sound.

MOOG’s Tanzania first

724 MOOG has secured its first order from Tanzania for one of the firm’s underbridge inspection units.
The customised MBL 1200 underbridge unit was sold to the Road Service of Tanzania (RST) – with the groundbreaking Deal making local German news.

The Tanzania-ordered unit will be located and used in the Lake Victoria area of the East African country. The lake is the largest lake in Africa and the third largest lake worldwide.

As specified by the customer, the machine has a horizontal range of 12m and an over-bridging of sidewalks up to 3.8m. This over-bridging can be achieved by a moving carrier plate, which helps make it possible to move the upper structure. @With a lowering depth of 15.5m and a working height of 16m, the unit can be used as an aerial platform as well. The vehicle complies with the Tanzanian Regulations regarding axle loads, overall weight and all other maximum measurements.

The unit has a 1.25m x 1.25m bucket and a maximum load of 280kg. It is equipped with and supported by a Deutz diesel generator, making it possible to use electrical tools while working in the bucket. The boom rotation area of 180° allows for erection from either side of the unit of up to 230m² and provides for the highest flexibility.

Handling and operating the unit is very easy because of the clear arrangement of the operating Controls. For work in the dark, the boom and the operating Controls are equipped with night lights to enable safe access and use of the unit. The Tanzanian unit is also equipped with an additional platform mounted to the bucket arm. With the help of this platform, small, intricate repair work can be done much more easily. Telescoping of the boom is locked out if using the additional platform and also the payload inside the bucket is reduced to 100kg. The payload of the platform is 200kg.

RST staff expected to use the underbridge inspection unit were trained on its operation and maintenance during a one-week training session led by a MOOG instructor.



Stirling Lloyd’s microsite for urban bridges

2314 Stirling Lloyd, the leading UK manufacturer of high performance waterproofing coatings for the protection of infrastructure and buildings globally, has launched a new website focused on urban bridges, one of its major growth markets.

The new micro site, http://www.bridgedeckwaterproofing.com/urbanbridges identifies the specific challenges facing modern day road bridge decks including traffic congestion, pollution, higher vehicle numbers and heavier transport loads, all of which increase the importance of planned and ongoing maintenance programmes including waterproofing and repair.

Focusing on its Eliminator advanced deck waterproofing system, Stirling Lloyd highlights a solution to the requirement for improved and sustained structural integrity and longevity of urban bridge stock, while helping to keep the traffic flowing through the maintenance period.

This advanced, spray-applied waterproofing system has an unparalleled track record of success spanning over four decades. It has been used to protect concrete and steel bridges of every design, type and size, in all climates and carrying every type of traffic on projects around the world including the most trafficked bridge in the world, the George Washington Bridge, New York and the busiest bridge in Europe, the Bosphorus II Bridge, Istanbul.

Development of this dedicated urban bridges microsite is part of a broader marketing campaign by Stirling Lloyd to reinforce its pedigree and products in this sector and develop new global opportunities in what continues to be one of its significant growth markets.


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