Friday, September 24, 2010

Last night's Sand Hill bridge meeting

Notes on this week's major meeting about the Sand Hill bridge project:

(NB: these notes are partial and incomplete, since I had to leave 90 minutes in)

Meeting occured in the East Middlebury Methodist Church. Two Vtrans engineers led the meeting; most of the pews were filled with East Middlebury and Ripton folk. Some stood.

Quick overview of Sand Hill bridge: it handles about 2000+ vehicles/day. It's an "arch bridge", and was built 1924. That 1924 date means mystery, at least in terms of what we know about the bridge's interiors. No plans survived, so engineers are not certain what lurks inside the arch.

Although Sand Hill has stood and served for decades, no one can determine its future safety with confidence, given the uncertainly surrounding its materials. A recent survey deemed its future "poor", adding urgency to plans for refurbishing or replacing it.

The two VTrans engineers presented their new plan. It involves maintaining the current bridge as an ornamental arch. New abutments will be added, on either side of the current bridge's ends; a new span will ride above the current bridge.

The new bridge includes a wider road, increasing the current width from 20 to 36 feet. This includes broadening the lanes, adding shoulders, and also adding on a sidewalk. Each lane will be 11 feet lane, and the shoulders stretch 3 feet from lane to edge.

Timeline: about one construction season, 3-4 months. VTrans thinks early construction incentives (cash) would help speed things along. May or June are likely starting months. Construction isn't likely to start anytime soon, as the VTrans engineers stated that they were back at square one for the project.

Many things need to be done for this to happen:

  • relocating utilities (electricity, maybe water)
  • stabilizing the East Middlebury side's slope. This could involve piling up rocks and dirt, or covering the slope with "geotextile", or even "soil nailing" (driving down longdowels).
  • adding extended retaining walls (maybe)

After these possible tasks were outlined, another then soaked up much discussion. This was the question of how to take care of traffic during contruction. Two options were presented.

  1. Setting up offsite detours was the VTrans preferred method. This means shunting heavy traffic (trucks) south to route 73. Lighter traffic (cares, buses, commuters) would have the choice of either taking North Branch Road, or the southern route through Lower and Upper Plains Roads. These offsite detours have the advantage of saving time.
  2. Building a temporary bridge, on either side of Sand hill. This would probably add a second season to the construction process, but have the advantage of allowing continued traffic without diversions.

Discussion followed with great intensity. To begin with, one speaker mentioned an emergency services problem, namely that the delay experienced by Middlebury EMS ascending the mountain along an alternate route could mean the difference between life or death. Fire support would probably never arrive in time to help.

Another speaker noted increasing safety problems likely to appear on an increasingly trafficked, even overcrowded North Branch Road (a very tricky, narrow road, compared with the Plains roads).

Others spoke in favor of diversions. One noted that the extra time required by the detours would probably not be that great, except for heavy traffic, and that Ripton was already used to the hardships of mountain life. VTrans argued that the extra time, expense, and effort involved in building a second bridge would be unduly burdensome.

At this point your humble notetaker had to leave the meeting, in order to put children to bed. He drove over the Sand Hill Bridge along the way.

Previous post about the meeting.


bill mckibben said...

Excellent report! Many thanks for this

Willem said...

Let's be clear about this detour business. For 3-4 months there will be signs at Route 7 (west end of the gap) and Route 100 (east end) reading "ROAD CLOSED - DETOUR OVER BRANDON GAP."

We will all find our way up and down and add about 2000 trips/day to upper and lower plans roads and the North Branch Road. I am concerned about the increased emergency response times, and the massive increase in traffic on those roads.

There are options including use of a temporary bridge or "phased construction." There will be a petition coming out shortly asking VTrans to consider the impacts of a long term closure carefully and to fully explore options that will keep this important east-west corridor open.

The Riptonites said...

Thanks, Bill.

Willem, would the detour signs specify only the 73 route, or would they also mention North Branch/Plains?