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

 

Forestry: Man Charged After 2013 Death

Levin Police have arrested and charged a man with manslaughter in relation to the death of Lincoln Kidd who was killed during a tree felling operation on 19 December 2013. More>>

ALSO:

Smells Like Justice: Dairy Company Fined Over Odour

Dairy company fined over odour Dairy supply company Open Country Dairy Limited has been convicted and fined more than $35,000 for discharging objectionable odour from its Waharoa factory at the time of last year’s ”spring flush” when milk supply was high. More>>

Scoop Business: Dairy Product Prices Decline To Lowest Since July 2012

Dairy product prices dropped to the lowest level since July 2012 in the latest GlobalDairyTrade auction, led by a slump in rennet casein and butter milk powder. More>>

ALSO:

SOE Results: TVNZ Lifts Annual Profit 25% On Flat Ad Revenue, Quits Igloo

Television New Zealand, the state-owned broadcaster, lifted annual profit 25 percent, ahead of forecast and despite a dip in advertising revenue, while quitting its stake in the pay-TV Igloo joint venture with Sky Network Television. More>>

ALSO:

Insurers Up For More Payouts: Chch Property Investor Wins Policy Appeal In Supreme Court

Ridgecrest NZ, a property investor, has won an appeal in the Supreme Court over insurance cover provided by IAG New Zealand for a Christchurch building damaged in four successive earthquakes. More>>

ALSO:

Other Cases:

Royal Society: Review Finds Community Water Fluoridation Safe And Effective

A review of the scientific evidence for and against the efficacy and safety of fluoridation of public water supplies has found that the levels of fluoridation used in New Zealand create no health risks and provide protection against tooth decay. More>>

ALSO:

Scoop Business: Croxley Calls Time On NZ Production In Face Of Cheap Imports

Croxley Stationery, whose stationery brands include Olympic, Warwick and Collins, plans to cease manufacturing in New Zealand because it has struggled to compete with lower-cost imports in a market where the printed word is giving way to electronic communications. More>>

ALSO:

Prefu Roundup: Forecasts Revised, Surplus Intact

The National government heads into the election with its Budget surplus target broadly intact, delivering a set of economic and fiscal forecasts marginally revised from May to reflect weaker commodity prices and a lower tax take. More>>

ALSO:

Get More From Scoop

 
 
Computer Power Plus

Standards New Zealand

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