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Article
The markets: Civil infrastructure (2015)

Aging infrastructure offers a potentially huge market for composite material, but the pace of adoption is halting, at best, due to continuing budgetary concern about the upfront cost of composites.

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Posted on: 1/12/2015
Source: CompositesWorld

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SkyPath

Although composites in bridges for trains and other motorized forms of transportation have yet to gain widespread application, composites are aa growing force in pedestrian and bike-trail bridges. One of the more celebrated is SkyPath, an addition to the existing Aukland Harbour Bridge in New Zealand. Construction crews this year will attach this enclosed, composite walking/cycling path, which features components made from composites. The 1.1-km-long pedestrian throughway will be fabricated, in part, with modular composite sandwich decking manufactured by Core Builders Composites (Warmouth, New Zealand). Scheduled completion date is by the end of 2016. Source: Gurit

                                                Cape Town Ship Pier 1

In South Africa, the Transnet National Ports Authority of Cape Town had a safety problem at its main container ship pier: A raised cable tray more than 1,200m long contains electrical cables that power rail-mounted gantry cranes used to load and unload ships. It was a trip hazard for dock workers. Cape Town-based composite materials supplier Aerontec proposed this raised composite deck solution, which weighed less and was finished faster than a poured concrete deck, and offered a much longer useful life under exposure to saltwater (see next photo). Source: Aerontec

                                                Cape Town Ship Pier 2

Aerontec partnered with South African fabricator MMS Technology (Centurion, South Africa) to manufacture and waterjet cut 1,161 panels of varying sizes. The total weight of all the composite panels was just 226 metric tonnes (500,000 lb) — within the cantilevered pier's weight-bearing constraint. Read more about this unusual civil engineering project by clicking "Quay cable tray: Composites upgrade container ship terminal," under "Editor's Picks," at top right. Source: Aerontec

                                                Cork park canopy

The term "civil infrastructure" typically conjures up images of bridges, roadways and dams. But structures for parks and public entertainment qualify as well. In that category is this most unusual pavilion canopy in Cork, Ireland’s Mardyke Gardens, the centerpiece of the city’s Fitzgerald Park. Constructed of glass-reinforced epoxy and designed to stand up to high wind loads and strong weather, the all-composite structure eliminated steel superstructure that would be subject to corrosion. The canopy's straightforward sandwich construction and simple internal supports allowed the fabricator, Isle of Wight, UK-based AM Structures Ltd., to build it offsite, using materials supplied by Gurt UK (Isle of Wight). That saved money, and reduced the canopy's weight, easing transportation and assembly time. Read more about this unusual project by clicking on "Pavilion canopy: Graceful lines, strength of steel," under Editor's Picks," at top right. Source Gurit Ltd.

Aging infrastructure offers a potentially huge market for composite materials. According to a report by the coalition Transportation for America (Washington, DC, US), titled The Fix We’re In For: The State of our Nation’s Busiest Bridges, there are 69,223 structurally deficient highway bridges in the U.S. alone — 11.5% of all U.S. highway bridges — that require rehabilitation or replacement. These numbers have stimulated development of a number of composites-enabled technologies.

The early deterioration of concrete due to the corrosion and failure of steel rebar has been well documented. Conventional repairs could cost billions. In many locales, the useful life of corrosion-prone steel-rebar-reinforced concrete is limited to 25 years, rather than the 75 to 100 years once promised by its advocates. Therefore, the lifecycle cost advantages, not to mention the safety benefits, of using composite rebar continue to overcome resistance among change-averse municipalities. That said, once significant activity among composites fabricators looking to replace entire bridge structures has quieted, replaced by a more conservative focus on replacing vulnerable, corrosion-prone concrete bridge decks with robust composite replacements on steel truss bridges.

Progress is still halting. Faced with limited annual budgets, state and local transportation executives have the choice to replace a certain number of bridges with concrete that could last 30-40 years at best, or half as many using composites that could last up to 100 years. In both cases, their careers will be long finished before anyone will hold them to account, so the easy answer is twice as many low-cost bridges.

Scott Reeve, president of Composite Advantage (Dayton, OH, US), says the day cannot be won on the lifecycle-cost argument alone. Reeve, whose company is among the most successful fabricators of composite bridge decks, particularly for pedestrian bridges, confirms that the “upfront cost” problem still exists. “A composite vehicle deck is about twice the price of a concrete deck. Even accounting for lower installation costs, we are probably 1.8 times the traditional solution. Until we can get that differential down to around 15%, market penetration will remain slow.”

Although numerous contractors use composite wraps for remediation of concrete bridge decks and columns, it doesn’t help fabricators of composite structures, says Reeve. Composites can capture vehicular bridge deck replacements where composites bring immediate value over concrete — for example, being able to reuse the existing structural elements, which would not otherwise be able to support the weight of a concrete deck, or the addition of a sidewalk where one did not previously exist. Integrated properly, composites can enable replacement of a bridge over a single weekend, clearly a benefit in congested cities.

Despite the resistance posed by economics, Reeve is a long-term optimist regarding the potential for composite bridge decks. “It took 30 years for steel to replace wood in bridge structures, so the opportunity to change the mindset is still there.”

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Quay cable tray: Composites upgrade container ship terminal

When the Cape Town, South Africa, Transnet National Ports Authority began a 12-month effort to expan...

Pavilion canopy: Graceful lines, strength of steel

All GFRP design eschews steel framing but can withstand wind and elements.


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