UC Civil Engineers Test Post-quake Designed Bridge Columns

UC Civil Engineers Carrying Out Critical Tests On New Post-quake Designed Bridge Columns

June 6, 2013

University of Canterbury (UC) civil engineering researchers are carrying out critical tests on new design bridge columns to improve the quality of bridges so they stand firm in earthquakes.

Most bridge abutments and piers are constructed using cast in place construction techniques meaning the bridge’s piers are formed on site using poured concrete.

But UC civil engineers are working on precast concrete piers that are poured off site which increases construction speed and quality, reduces traffic disruption and increases construction safety.

The Ministry of Science and Innovation – New Zealand Natural Hazard Platform has granted more than $600,000 over four years for the stronger bridge building project.

The use of precast concrete for rapid bridge construction is known as Accelerated Bridge Construction (ABC).

The research is being supervised by Dr Alessandro Palermo with support from civil engineering master student Sam White.

``This ABC method can save up to 50 percent of construction time. ABC is critical and important as all the big construction companies gear up for the Christchurch rebuild and important national projects like Transmission Gully in Wellington cannot afford to be without ABC solutions.

``If all parts were manufactured in a factory, the labour required is far less than cast in place on site. This new ABC method will provide sustainability for New Zealand construction companies in carrying out big projects in Auckland, Wellington and Christchurch.’’

Bridges constructed before the earthquakes guaranteed life safety but, as we have seen, they can disrupt traffic. In Christchurch 10 to 15 percent of bridges have been closed or had traffic restriction for up to several months. This will not happen with the new ABC bridge constructions.

``Post-earthquake serviceability of bridges, especially those on main roads, is essential for mobilising earthquake rescue personnel. Moorhouse Avenue bridge in the Christchurch CBD was closed for a month and the Ferrymead bridge which carried 35,000 vehicles a day has had traffic restrictions for more than a year,’’ Dr Palermo says.

The UC testing continues on from previous research looking at precast connections using member socket connections and grouted duct connections to emulate cast-in-place connection behaviour.

Testing is being undertaken at UC to explore the performance of controlled damage connections in a half scale precast concrete bridge pier. Sam White is conducting a series of earthquake testing proving the superior performance of these connections compared to the currently designed cast in place bridge columns.

The test columns and footings weigh about seven tonnes with an additional 90 tonnes axial load being added through the use of tensioned steel bars.

UC recently jumped more than 30 places to be ranked 21st in the world in Civil and Natural Resources Engineering.

Photo, from left to right:  Dr Alessandro Palermo and postgraduates Sam White and Mustafa Mashal at the UC bridge testing site.

ENDS

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