Quote:
Originally Posted by craner
I'm just asking - they built separate structures for the LRT anyway, would it have cost a "fortune" to raise them above the road.
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There are three spans that were built for each track, 90-95m over Nose Creek / CPR, 110-120m over Deerfoot and 40-45m over the NB Deerfoot to EB Memorial ramp. Total about 250 m. In these cases, there were no major earthworks needed, since the interchange exists. The shortest span doesn't even need a support column. If a separate structure would have been built, it would have had to start shortly after the Zoo platform (to climb enough to be over the road), and would be back on solid ground somewhere parallel to 18 St SE. That's roughly 850m, over three times as long. Furthermore, the engineering would be a lot more difficult, since the columns that were built would be much higher; that is, instead of 6.5m to provide clearance on Deerfoot, the LRT bridge deck would be 13 m high to provide clearance over both the turn movement and Deerfoot below. If I remember my structures correctly (note - there's a reason I'm in transportation and not structural engineering), doubling a column length requires squaring the strength to avoid buckling. So that adds an additional measure of cost, on top of the structure being three times as long.
The two movements that cross the LRT are WB Memorial to SB Deerfoot and SB Deerfoot to EB Memorial.
Volumes (2011 count; 7AM-7PM) are:
Code:
NB Deerfoot to: WB Memorial - 3,100
NB Deerfoot - 42,200
EB Memorial - 14,300
SB Deerfoot to: EB Memorial - 7,100
SB Deerfoot - 38,800
WB Memorial - 10,200
EB Memorial to: SB Deerfoot - 5,800
EB Memorial - 14,000
NB Deerfoot - 3,200
WB Memorial to: NB Deerfoot - 10,900
WB Memorial - 17,700
SB Deerfoot - 7,800
About 15K vehicles 7AM-7PM, that's only 8.5% of all traffic, and around 20K vehicles per day. Roads with similar volumes include Ogden Road at the Bonnybrook waste water plant, 68 St NE south of McKnight and Elbow Dr. south of Heritage.