Timber bridges at breaking point

Loading has been shifted to the side of the bridge less impacted by decay.
Loading has been shifted to the side of the bridge less impacted by decay.

Heavier vehicles planning to cross Beaury Creek via the bridge on Tooloom Rd will need to find an alternative route for the time being as major structural problems have been discovered.

A 5 tonne temporary load limit was placed on the Beaury Creek bridge on Monday evening, September 25 following an inspection of the bridge by Tenterfield Shire Council’s chief operating officer Andre Kompler. He confirmed first hand that the extent of problems at the old 1934 three-span timber bridge are more extensive than indicated in a June 2017 independent bridge inspection.

These include a broken central girder, an outer compromised split girder and significantly reduced pile-bearing capacity at one of the trestle piers.

Council has shifted the loading to the side of the bridge less impacted, in order to centralise loading over the remaining two girders.

“After having observed the bridge’s response to loading by Rural Fire Service and council light trucks, council is of the view that the bridge should be trafficable in the medium term, if the community and businesses respect the five-tonne load,” Mr Kompler said.

The extent to which the load limit can change will be determined in October after independent non-destructive ‘mod shock’ testing is completed and recommendations given on both the revised load limit and cost-effective repair options, or recommendation on total replacement.

The extent of problems at the old 1934 three-span timber bridge are more extensive than advised.

The extent of problems at the old 1934 three-span timber bridge are more extensive than advised.

“While council is conscious that this action will impact logging business in the area, school bus routes and affect traffic to and from Urbenville, public safety is paramount, thus the load limit,” Mr Kompler said.

While council has close to $700,000 allocated to timber bridge repairs this financial year and limited capital expenditure funding to contribute to a number of small bridge replacements, Mr Kompler said available funding is unlikely to come even close to dealing with the long term needs at Beaury Creek.

In September council put forward submissions for bridge replacement assistance from the NSW State Government’s Fixing Country Roads grant program for another two poor-quality structures: Emu Creek Bridge on Hooton’s Road and Boonoo Boonoo bridge on Mt Lindesay Road. Their fate will not be known for some months.

Regardless, Mr Kompler said council will look at possibilities for limiting the impact on the community through possible reallocation of some of its current 2017/2018 financial year funding to explore temporary Bailey bridging (a type of portable, prefabricated truss bridge) or the like, along with ministerial representation for an emergency funding contribution towards a new structure.

“However it may well be that the duration of community inconvenience is protracted,” Mr Kompler said.

“With 58 old timber bridges in Tenterfield Shire at varying levels of condition, it does not take much to break the back of a bridge such as what has happened at Beaury Creek, so the challenge for council in the near term will be to get up-to-date structural assessments of load carrying capacity of its timber bridges and putting in place load limit restrictions at suspect bridges as soon as possible to ensure bridge assets remain functional until funding is available for long term bridge replacements.”

Council advises that traffic travelling between Tenterfield and Urbenville can travel Mt Lindesay Road to Woodenbong and then south via Clarence Way, an additional 16 kilometres of travel. For community and business south of the bridge around Paddy’s Flat Road and Wallaby Creek Road heading to Urbenville, the alternate route will be via Tooloom Road, Mt Lindesay Road to Woodenbong and south via Clarence Way, an extra 70 kilometres of travel.

 Load limit changes will advised when available.