In earlier blogs I questioned why it was going to take as long to widen the spans as it was to widen the whole motorway, and why buses and trucks may not be allowed to use the bridge after April of next year until the work is finished.
That was explained very nicely by Peter Colacino of Transurban and a member of his team at the BCCT AGM the other day.
The problem is they have to build a new buttress to support the bridge, in between the two new roadways. They can only do that when the new east-going roadway is built. Meanwhile they have to dig out the bridge on that side before they can build that wider east-going roadway under it, and there will be a time when the eastern span is wider than the original designers intended, supported only by the existing buttress. Transurban engineers will decide before then what weight the wider span can carry and decide what weight limit to apply.
When the wider east-going lane is built, the new buttress can be built to support it, and the existing buttress can then be removed to allow the west-going lanes to be finished. Normal weight limits will hopefully then be restored.
A very complex planning process! Every step is interlinked with steps before and after. Thanks for the explanation, Peter.
(This post was prompted by a question in an email from Elise of MSB)
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