Central Victorian councils highlight the importance of maintaining bridge networks

HEAVY LOAD: One of the bridges located at the Ravenswood Interchange. Picture: NONI HYETT
HEAVY LOAD: One of the bridges located at the Ravenswood Interchange. Picture: NONI HYETT

Councils across central Victoria have emphasised the importance of maintaining their bridge networks as the structures become aged, and traffic and vehicle loads increase.

Routine inspections must be carried out on the hundreds of bridges to ensure their structural integrity is suitable for modern usage.

City of Greater Bendigo

City of Greater Bendigo manager of engineering Brett Martini said all bridges within the city underwent three levels of safety inspections.

“First is an annual visual inspection which looks at any maintenance issues and highlights if any further works or investigations are required,” Mr Martini said.

“Second is a more detailed analysis of the particular structural elements of the specific bridge.

“The third level of testing involves detailed electronic testing of any deflection and movement in elements of the bridge.

Despite truck load weights increasing, one of the major factors for engineers when looking at bridge load weights is analysing how the weight is distributed across the structure.

“It’s not only about the total mass of the vehicle, it comes down to the configuration of the wheel axis and how the load is spread across the bridge,” Mr Martini said.

The COGB has very few timber bridges remaining out of the approximate 240 within the city.

However, a timber bridge north of Axedale will receive some maintenance work over the next two years to improve its strength, while retaining its historical significance.

Campaspe Shire Council

BRIDGES: The bridge on Fox Island Bridge Road, Gunbower is one of the many in Campaspe Shire that will be replaced. Picture: SUPPLIED

BRIDGES: The bridge on Fox Island Bridge Road, Gunbower is one of the many in Campaspe Shire that will be replaced. Picture: SUPPLIED

The Campaspe Shire Council will be progressing an inspection program throughout the shire where a specialist engineer will undertake inspections to assess the structural integrity of all the council-owned bridges.

Campaspe Shire mayor Adrian Weston said they were in an unusual position of owning numerous bridges constructed prior to 1976.

“Prior to 1976 bridges were designed to carry loads of 33 tonnes, with today’s bridges designed to carry loads of 160 tonnes,” Cr Weston said.

“Modern trucks and commercial vehicles have increased in size and weight over the years, stressing older bridges beyond their capacity.

“In recent years design guidelines have changed to address the structural needs and materials have improved to support structural demands.”

According to Campaspe Shire the general life span of a bridge was 80-100 years.

However, an increase in load and levels of traffic using the bridges has escalated beyond its capacity, having a negative impact on the network. 

“This has resulted in load limits placed on a number of bridges to date, however as further structural assessments are completed it is evident there will be many more to come,” Cr Weston said.

“We must take actions now or face many of our bridges closing, which will not only affect larger transport users, but the wider community for regular vehicles access.

Load limits have recently been placed on Groves Bridge near Colbinabbin and Floodway Bridge near Stanhope.

“If we ignore restrictions, bridges will eventually close temporarily or permanently and we want to avoid this,” Cr Weston said.

Mount Alexander Shire Council

The Mount Alexander Shire Council has 229 bridges and culverts across the shire which are inspected annually by trained council officers who assess the structures for any potential hazards.

A spokesperson for the council said every four years a qualified consultant provided a detailed report which included any plans for potential maintenance or renewal.

“We have just finished the most detailed condition assessment of our bridges and we are currently reviewing the data, which helps us prioritise bridges for replacement and maintenance,” the spokesperson said.

“This may flag the need for a load limit to be applied to the bridge in order to extend the life of the structure.

“Most bridges with load limits are on the program for replacement and will be assessed against a number of other criteria to further prioritise the works.”

There are 19 bridges within Mount Alexander Shire with active load limits.