Troubled bridges hang in City Council balance
Bond project includes replacing Red Bud Isle bridges.
The two low-slung bridges, joined by Red Bud Isle in the middle and leading to the Colorado River’s east and west banks, stand as a relic from another time.
The 68-year-old bridges’ two lanes and slender sidewalk on the south side, measuring just 28½ feet in width, are stressed by a daily load of 13,000 cars, some nervy cyclists and a dozen or so heavy sludge trucks serving Austin’s Ullrich Water Treatment Plant up the hill to the west.
The bridges, engineers decided long ago, are functionally obsolete, and they’re rated as being in “fair” condition, based on twice yearly inspections. While they consider the bridges — named for West Lake Hills founder Emmett Shelton — to be safe for traffic and have imposed no load restrictions, City of Austin officials have been looking to replace them for at least a decade.
“Despite this seemingly acceptable rating, we are concerned that the somewhat cursory visual inspections performed are highly overrating the structural capacity” of the bridges, engineers said in a September 2017 city report.
This fall, it appears Austin voters will get a chance to launch a long-delayed $50 million project to replace what longtime Austinites have always called “the low water bridge,” situated just downstream of Tom Miller Dam. In August, the City Council will vote to call an election on what at this point amounts to $925 million in
potential borrowing through bonds, presenting voters with up-or-down decisions in six subject areas.
Subject to further changes by the council, that would include a $160 million bond proposition for transportation projects. That ballot measure would include $50 million for bridges and culverts, and all that slice, offi- cials said, would go toward replacing the Shelton bridges unless the city lands state or federal grants for a portion of the work.
West Lake Hills, Austin city officials said, is unlikely to be a financial contribu- tor. West Lake Hills Mayor Linda Anthony could not be reached for comment Thursday.
The new bridges would be 55 to 60 feet wide, Austin Public Works Director Rich- ard Mendoza said, with two vehicle lanes, wide shoulders, a broad concrete path for cyclists and pedestrians, and a piece for the water and wastewater mains that now hang from the bottom of the existing bridges. The new bridges would be as much as 20 feet higher above the water, according to published early designs.
The city still doesn’t know the path of the replacement bridges, however. Mendoza said three potential align- ments remain in the mix, two north of the existing bridges and a third slightly south. The southerly route would require gouging out — or blasting away — a new pathway into the cliff on the river’s west side.
That promontory is home to a number of large houses, including one just 100 yards or so south of where the new road cut might go. The two northern options are farther away from development.
“I can’t rule out explo- sives,” Mendoza said, “but there are other excavation means and methods. We would be sensitive to the community.”
All three bridges would connect to Red Bud Trail at a much higher elevation than the current road,
and eliminate much of a S-curve leading to the cur- rent bridges that, according to a city report, was the site of 81 vehicle accidents over a 12-year period.
“That S-curve was designed 70 years ago, and that degree of sharpness would never be designed into a current road with this degree of traffic,” Mendoza said.
Assuming voters approve the bonds, Mendoza estimated the new bridges would be open to traffic in four to five years, including up to three years of construction. The existing bridges would remain open to traffic during construction, he said, and the final design would include access to the popular off-leash dog park on Red Bud Isle.
Austin City Council Member Alison Alter, whose District 10 includes the bridges, said the commitment of $50 million is necessary so engineers can complete an engineering and environmental study and then build the project. The study so far has been funded with $3 million approved in a 2012 bond election.
With a completed study in hand, Alter said, the city could then compete for grants, potentially allowing at least a significant portion of the $50 million to go to other bridge or culvert projects. The city, for instance, also would like to widen the Barton Springs Road bridge over Barton Creek.
“You have to have your pretty pictures and designs to bring other people along in the process,” Alter said Thursday. “The bridge is a really critical way in and out of that area. For the water plant to function, which serves over a third of the city, that requires a level of access.
“We have to make investments in our infrastructure. Unfortunately, sometimes it’s way more expensive than we hope or think it ought to be.”