Auckland's harbour bridge clip-ons could be candidates for "orthopaedic surgery" which would enable walking and cycling paths to be added and could improve their longevity.
The Transport Agency has been given a proposal by engineering consultants working with the Getacross campaign to find ways of adding walking and cycling links without shortening the life of the 40-year-old clip-ons.
The proposal from the award-winning Holmes Consulting Group - for two "orthopaedic diaphragm" beams to be slung under the main arch section of the bridge to support the clip-ons running along both sides of the structure - is being examined by the agency's bridge engineering specialists in New Zealand and Britain.
It features a load-sharing mechanism by which the main truss bridge would support proportions of peak loads on the clip-ons, reducing metal fatigue by limiting their vertical movements.
Getacross spokesman Bevan Woodward said last night that he understood the diaphragm beams would cost no more than about $10 million to install, although he acknowledged that would be in addition to the price of adding extra structures on both edges of the bridge for walking and cycling.
NZ Herald report 20/08/09