Traditional or modern: which bridge design will it be?
With the recent opening of the temporary Lagoon Pond drawbridge, called the Crooked Bridge by some, Islanders can now turn their attention to its permanent replacement.
The Lagoon Pond Drawbridge Committee wants Islanders to weigh in on two proposed designs for the permanent drawbridge, which include a traditional style, top, and a modern one.
Last week, MassHighway personnel and a design team from Parsons Corporation unveiled illustrations of the new permanent drawbridge, now at the 25 percent design and sketch phase, to the Lagoon Pond Drawbridge Committee (LPDC).
"I just want to say first of all, to our guests from Boston, that we are thankful and appreciative that we have a new bridge that's reliable and workable," LPDC chairman Melinda Loberg said in opening the meeting at the Martha's Vineyard Commission (MVC) offices.
For those who might harbor concerns about the temporary bridge's longevity, MassHighway project manager Steve McLaughlin cut right to the chase.
"Let me say this straight out: The temporary bridge is nice, it's working well, and we don't want to keep it there," he said. "So, I know you guys like it a lot, you want to keep it, but we want to replace it pretty soon. It is temporary."
Although the recent focus has been on the temporary drawbridge's construction, plans for the permanent bridge have been moving forward all along.
Parsons project manager Leslie Haines said the project reached an important milestone with the submission of a preliminary road plan in mid-December and bridge sketch plans in early January for state agency approvals.
Preliminary Landscape Design
"The next big stage is once the 25-percent highway plans get approved, we have the design public hearing, and then we go forward into final design and work out all the final details of the project," she said.
Based on comments from members of the LPDC and the public from past meetings, William H. Lockwood of Lockwood Architects proposed several bridge design concepts. Those were reduced to the two versions in illustrations accompanying this article, one modern and one traditional, presented at last week's meeting.
MassHighway landscape designer Andrew Schlenker also provided an illustration of the preliminary landscape design for the bridge area.
While the bridge and roadway are the same in both design versions, the difference is in materials used, types of railings, and the style of the bridge tender's hut.
"What we're hoping today is to come out with between these two options, one very traditional and one very modern, is an idea of what the committee wants to carry forward with the final design," Ms. Haines said.
The version the committee chooses will be "tweaked" for presentation at the public hearing, she added.
After getting the LPDC's feedback, Mr. McLaughlin said the goal is to schedule a public hearing to present the drawbridge design to a wider audience and accept comment for the record, probably at the beginning of March.
Before then, Ms. Loberg said the LPDC wants to hear from the Island community.
"What we'd like is for people to send commentary to Mark London via email or come to the drawbridge committee's next meeting on February 12, at noon, at the MVC offices," she said. "This meeting is really about the aesthetics of the new permanent bridge."
Mr. London's email address is London@mvcommission.org. Written comments may also be mailed to the MVC, P.O. Box 1447, Oak Bluffs, MA 02557.
After hearing from the public at the meeting, the LDPC will choose one of the two design versions, Ms. Loberg said. "We want to make comments to the state very soon, and then they can get into the 25 percent design public hearing," she said.
Based on the results of several studies, including a marine clearance study that tracked the number and height of boats going in and out of the Lagoon, Parsons Engineering presented a bridge type study report in 2008 from which the recommended design was derived.
Coming up with a design to eliminate the "dog leg" in the navigational channel proved challenging. Although the goal was to move the channel by 30 feet, given the old bridge's configuration, the Parsons design team determined that would require an 80-foot bascule (draw) span, which would affect the bridge profile and cost more.
Making the bridge higher also was not a good option, because the approaches would have to be longer and steeper and possibly encroach on the entrance to Eastville Beach.
Instead, the design team came up with the idea of using a 50-foot bascule span and moving it one span closer to Tisbury, so that it is completely outside the existing channel. The shift allowed for a second channel under the fixed part of the bridge.
At last week's presentation, Ms. Haines said there would be 15 feet of clearance in the channel near the bridge tender's hut and 19 feet of clearance in the channel under the draw span. That will allow more capacity for smaller boats to go in and out of the Lagoon with fewer drawbridge openings.
A video simulation of a boat going under the bridge and the drawbridge's opening and closing will be shown at the public hearing, Ms. Haines said.
In the 25 percent plan, approaching from Oak Bluffs the drawbridge consists of four 46-foot spans, a 50-foot bascule span, a small 20-foot counterweight span, and two 46-foot spans on the Tisbury side. Based on geo-technical investigations, Ms. Haines said all of the bridge's foundation would be on piles.
Illustrations of the two design versions were made by superimposing a three-dimensional image of the new bridge over a photo of the old drawbridge taken from the Vineyard Haven harbor side.
As Mr. Lockwood explained, the more traditional version features rusticated stone or form liners with a stone-like pattern on the abutments, retaining walls, and bridge tender's hut, while the modern version uses concrete.
Although sketch plans call for stone facing, Ms. Haines and Mr. McLaughlin recommended form liners instead, which are cheaper and faster to use, and come in many patterns and colors.
MVC executive director Mark London pointed out that form liners are being used on the Big and Little Bridges under reconstruction on Beach Road between Oak Bluffs and Edgartown.
The differences between the two design versions are most noticeable on the bridge tender's hut. The traditional design features a shingled hip roof, angled on all sides. The modern roof design is flat and sharply angled on one side to maximize the efficiency of solar panels on top.
Unfortunately, Mr. Lockwood said, it would not be possible to incorporate solar panels in the more traditional roof design because of its pitch.
Solar energy produced would probably be enough to power lights in the operator's hut and on some equipment, but not enough to power the bridge, Ms. Haines said.
Most of the LPDC's discussion focused on the multi-use pathway (MUP) and its access on both sides of the bridge.
To accommodate the MUP the bridge committee wants, Ms. Haines said it was necessary to change the design by raising the bridge's profile by three feet.
Additional survey was required to see where the multi-use path the LPDC wanted would fit. Based on survey results, Ms. Haines said the design team increased the bridge length from 338 ft. to 350 ft., which allowed room for paths in front of the abutments on both sides without encroaching into the water.
Design plans for the bridge roadway remain the same, Ms. Haines said. The increased bridge length does not impact the entrance to Eastville Beach.
The drawbridge project is scheduled for completion in 2013. The cost of the permanent bridge is estimated at $35.7 million.
The Lagoon Pond Drawbridge Committee wants Islanders to weigh in on two proposed designs for the permanent drawbridge, which include a traditional style, top, and a modern one.
Preliminary Landscape Design
