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

 

Housing Policy: Auckland Densification As Popular As Ebola, English Says

Finance Minister Bill English said calls by the Reserve Bank Governor for more densification in Auckland’s housing were “about as popular in parts of Auckland as Ebola” would be. More>>

ALSO:

Crown Accounts: NZ Government Deficit Smaller Than Expected In First Half

The New Zealand government's operating deficit was smaller than expected in the first six months of the financial year, as the consumption and corporate tax take rose ahead of forecast in December, having lagged estimates in previous months. More>>

ALSO:

Fruit & Veg Crackdown: Auckland Fruit Fly Find Under Investigation

The Ministry for Primary Industries (MPI) is investigating a find of a single male Queensland fruit fly in a surveillance trap in the Auckland suburb of Grey Lynn... MPI has placed legal controls on the movement of fruit and some vegetables outside of a defined circular area which extends 1.5km from where the fly was trapped in Grey Lynn. More>>

ALSO:

Scoop Business: Westpac NZ Reaches $2.97M Swaps Settlement

Westpac Banking Corp’s New Zealand unit has agreed to pay $2.97 million in a settlement with the Commerce Commission over the way the bank sold interest rate swaps to farmers between 2005 and 2012. More>>

ALSO:

Going Dutch: Fonterra Kicks Off $144M Partnership With Dutch Cheese Maker

Fonterra Co-operative Group, the world’s largest dairy exporter, has commissioned a new dairy ingredients plant in Heerenveen, in the north of the Netherlands, its first wholly-owned and operated ingredients plant in Europe. More>>

ALSO:

Scoop Business: NZ Retail Sales Beat Estimates

New Zealand retail sales rose more than expected in the fourth quarter, led by vehicle-related transactions, food and beverages, adding to evidence that cheap credit and a growing jobs market are encouraging consumers to spend. More>>

ALSO:

Delivery Cuts Go Ahead: 'Government Money Grab' From NZ Post

"It's a money grab by the Government as the shareholder of New Zealand Post" says Postal Workers Union advocate Graeme Clarke about the changes announced by NZ Post. More>>

ALSO:

Get More From Scoop

 
 
Standards New Zealand

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