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

 

Trade Agreements: TPP Minus US Starting To Gain Ground

The Japanese government is picking up the pace on reviving the Trans-Pacific Partnership trade and investment deal, with talks scheduled next month among the 11 countries left in the pact after the withdrawal by the US after the election of president Donald Trump. More>>

ALSO:

PACER:

Prices Up 2.2%: Annual Inflation Highest In Over Five Years

"Rising petrol prices along with the annual rise in cigarette and tobacco tax lifted inflation," prices senior manager Jason Attewell said. "Petrol prices in New Zealand are closely linked to global oil prices, and cigarettes and tobacco taxes rise in the March quarter each year". More>>

ALSO:

Undertaxed? NZ Income Tax Rate Second Lowest Among Developed Nations

New Zealand workers pay the second smallest portion of their income to the government among developed nations and less than half the average ratio of their Organisation for Economic Cooperation and Development peers. More>>

ALSO:

Cyclone Cook: Round Up Of This Week’s Weather

One of the significant impacts this week was flooding due to excessive rainfall amounts. Rainfall amounts topped out at 350mm over the past 60 hours in parts of northwest Nelson, with 200mm+ measurements recorded about Coromandel Peninsula, and between 150-200mm in the Kaimai Ranges. Rainfall amounts of between 30-50mm were commonplace elsewhere. More>>

ALSO:

Earlier: Batten Down The Hatches For Cyclone Cook

Although fast-moving, Cyclone Cook will be destructive and MetService Expert Meteorologists have issued Severe Wind Warnings for the whole of the North Island apart from Northland... More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news