06-27-2021, 11:33 PM
(This post was last modified: 06-27-2021, 11:38 PM by danbrotherston.)
(06-27-2021, 10:27 PM)ijmorlan Wrote:(06-27-2021, 08:42 PM)danbrotherston Wrote: The proposed causeway is enormous, almost 1/4 of a km long. Leaving aside the expense, such a long distance takes away the opportunity to make recreation space in the green area, as well as a direct connection to Dutton Dr.
A bridge must be significantly higher because double large trucks use the highway, where as even a high airy human sized tunnel would be significantly smaller.
Whatever technique the bridge uses to reach ground level towards Northfield Station, it or a branch of the bridge can do the same to reach towards Dutton Drive. And I don’t see what the presence of the bridge has to do with use of the space for most recreational purposes — just run a ground-level path over from where the bridge starts.
The height of the bridge above the road won’t make much difference. It’s just a matter of how long the posts have to be — maybe 5m. One 50m up or something would be way more expensive of course. Digging for a tunnel is always going to be very expensive, especially given how wide it would have to be to make people comfortable. The floor of a tunnel would have to be at least maybe 3m below grade (guess) so getting back up to the surface would be a significant distance unless the ground slopes downwards away from the expressway.
That will almost double the cost of the bridge to do so, by building two ramps.
And yes, you could run a trail back from the end of the bridge, but having the trail move THROUGH the green space at ground level, I believe would significantly improve the connection to it.
The height of the bridge is what is driving the length of the causeway. The ground slopes slightly away from the expressway because of superelevation around the turn, but the biggest difference would be the height of the tunnel. A 3 meter rise would only take 36 meters (for an ADA compliant ramp), where the bridge approach shown in the renders is approximately six times longer. That would put ground level well within the greenspace for the ramp.