Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Investigation: Earthquake Impact On Chch Pedestrian Bridges

Investigations Into The Earthquake Impact On Christchurch’s Pedestrian Bridges
November 1, 2012

Many Christchurch pedestrian bridges were damaged in the Canterbury earthquakes and more than 50 percent of the bridges in the city will need to be repaired.

Bridges, such as the Dallington pedestrian bridge which crosses the Avon, were damaged by the lateral spreading of the river banks crushing the bridge deck.

Others, such as the South Brighton Road bridge and the Anzac Drive bridge, were respectively damaged by movement of the abutments (which support each end of the bridge) and also severe bending of the bridge piers which caused concrete cracks and spalling (the cracking/expulsion of the concrete cover which protect bars from corrosion) to occur on the bridge piers.

For a final research project, a University of Canterbury (UC) civil engineering student, Royce Liu, is investigating how to mitigate such damage in future and also to research new technologies which can be used to aid the achievement of less damage to bridges.

``I am especially interested about seismic structural engineering and how that can apply to bridges which are very important for the transport of goods and allowing people to safely cross rivers. Next year I'll work on this project with classmate Matthew Henden under Dr Alessandro Palermo's supervision.

``We will be studying technologies which could reduce damage caused by earthquakes on bridges as well as the effect that the shape of the bridge deck has on its seismic performance. A technology that we will be looking at is the use of rocking bridge piers.

``These piers are different to normal bridge piers because they are made up of concrete segments held together by a pre-stressed steel cable and have replaceable short steel rods which connect each block from one to another. The reasoning for having such a system is that in an earthquake, the blocks which make up the bridge pier can move relative to one another reducing the stresses created in the concrete and stopping large cracks from forming.

``Also the movement of the blocks is resisted by the short steel rods which are deformed as the blocks move past one another and dissipate the energy given to the blocks by the earthquake (this is very similar to bending a paper clip back and forth which creates a resistance to the bending motion and dissipates the energy you put in by deforming and heating up). Finally the pre-stressed steel cable pulls all of the blocks back into line so that the bridge piers are as they were before the earthquake.''

This type of technology was most applicable to large highway bridges, such as the Port Hills highway overbridge in Christchurch, and could reduce damage and cost of repair to bridge piers as well as reducing the down time of the bridge. The technology has been already implemented in buildings and NZTA is now looking with interest in possible application for bridges.

UC’s Dr Alessandro Palermo has just presented two days ago as invited speaker at the first national conference on bridges in Wellington.

Photo: Royce Liu


website: www.canterbury.ac.nz

ENDS

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Sky City : Auckland Convention Centre Cost Jumps By A Fifth

SkyCity Entertainment Group, the casino and hotel operator, is in talks with the government on how to fund the increased cost of as much as $130 million to build an international convention centre in downtown Auckland, with further gambling concessions ruled out. The Auckland-based company has increased its estimate to build the centre to between $470 million and $530 million as the construction boom across the country drives up building costs and design changes add to the bill.
More>>

ALSO:

RMTU: Mediation Between Lyttelton Port And Union Fails

The Rail and Maritime Union (RMTU) has opted to continue its overtime ban indefinitely after mediation with the Lyttelton Port of Christchurch (LPC) failed to progress collective bargaining. More>>

Earlier:

Science Policy: Callaghan, NSC Funding Knocked In Submissions

Callaghan Innovation, which was last year allocated a budget of $566 million over four years to dish out research and development grants, and the National Science Challenges attracted criticism in submissions on the government’s draft national statement of science investment, with science funding largely seen as too fragmented. More>>

ALSO:

Scoop Business: Spark, Voda And Telstra To Lay New Trans-Tasman Cable

Spark New Zealand and Vodafone, New Zealand’s two dominant telecommunications providers, in partnership with Australian provider Telstra, will spend US$70 million building a trans-Tasman submarine cable to bolster broadband traffic between the neighbouring countries and the rest of the world. More>>

ALSO:

More:

Statistics: Current Account Deficit Widens

New Zealand's annual current account deficit was $6.1 billion (2.6 percent of GDP) for the year ended September 2014. This compares with a deficit of $5.8 billion (2.5 percent of GDP) for the year ended June 2014. More>>

ALSO:

Still In The Red: NZ Govt Shunts Out Surplus To 2016

The New Zealand government has pushed out its targeted return to surplus for a year as falling dairy prices and a low inflation environment has kept a lid on its rising tax take, but is still dangling a possible tax cut in 2017, the next election year and promising to try and achieve the surplus pledge on which it campaigned for election in September. More>>

ALSO:

Job Insecurity: Time For Jobs That Count In The Meat Industry

“Meat Workers face it all”, says Graham Cooke, Meat Workers Union National Secretary. “Seasonal work, dangerous jobs, casual and zero hours contracts, and increasing pressure on workers to join non-union individual agreements. More>>

ALSO:

Get More From Scoop

 
 
Standards New Zealand

Standards New Zealand
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news