On Oct. 22, representatives from Vtrans presented findings from their Scoping Report for Cavendish ER BRF 0146 (13) Bridge #1 on VT Route 131 over Twenty Mile Stream prepared by T. Y. Lin International to the town of Cavendish.Members of the audience were invited to comment about the report and to identify concerns about the proposed bridge replacement.
The current bridge, built in 1947, is a 128 ft long, two-span, simply supported steel girder bridge, with a non-composite concrete deck. The bridge is set on a 45 degree skew, although the stream beneath is not well aligned with the substructure. During tropical storm Irene, the south abutment was significantly under minded. The abutment cracked vertically near the middle of the bridge in two locations between girder lines, with the east half of the abutment settling about 3 inches, causing the girders to pull away from the deck.
Because route 131 is such an important East/West corridor for the state, and the deficiencies are so significant, causing weight load restrictions, it was determined that the best option was to replace the bridge. As there are no significant issues around wetlands, habitats, agricultural soils, floodplains, archaeological issues or historic resources, the project was assigned to a newly formed “Accelerated Bridge Program.” The purpose of this program is to reduce the amount of time it takes to get a bridge replaced from five to two years.
Three primary options were considered: Temporary Bridge; phased construction-leaving one lane open so traffic could continue; or bridge closure and detour. According to the Scoping Report, the most viable option was to close the road and replace the bridge with a steel girder with precast deck panels. The costs were estimated to be $1,935,000, which was the least expensive of the three options considered. While phased construction was projected to cost $1,960,000, this was not selected as “Phased construction on the existing road is something that contractors prefer to avoid since it can create a more constrictive working condition, require earth retention systems for construction, and will increase the project duration since every task has to be performed at least twice and MOT operation need to be reset and maintained.” It was estimated that a phased construction approach would take 10 months, requiring two seasons to complete the project.
Because a lot of the work is precast, it will be done offsite, requiring a maximum of 35 days when the road would be closed and a detour would be in place. The public detour would be heading west, 106 to 10 to 103-adding 14.1 miles distance traveled. The local detour, which would not be posted for public use, would be Brook Road to Hoey to Center Road to Whitesville Rd to 131-adding 2.8 miles traveled.
Members of the audience brought up a variety of concerns, some of which were based in past experience when Route 131 was closed for two months following Irene. Trucks and thru traffic ignored the signs and used the local access routes creating significant issues for High Street residents.
There were concerns that Brook Rd was not going to be able to handle the increase in local traffic. It was noted that the Brook Rd Bridge currently has a weight restriction of three tons. This was to be replaced this year, but since the town is still waiting for FEMA funds, it has been postponed until the 2013 construction season.
Several heavy equipment contractors live in the Brook Rd area. At least one voiced concern about their ability to move their equipment because of the proposed detour.
The Vtrans representatives said that unlike Irene, there would be sufficient time for planning and there would be a dedicated signage approach. Further, Vtrans staff would work with the town to plan for the maximum 35-day closure. They also suggested that the town be given funds to help with local traffic control. Finally, the project would not take place until after May 15, 2014, which should be sufficient time to repair the Brook Rd Bridge.
Jeff Davis, Fire Chief for Cavendish Fire Department, was very concerned about response times for those living East of the bridge as well as being able to provide mutual aid to Weathersfield and Reading fire departments. Vtrans believed that the two adjacent town fire departments could provide coverage during the closure for those on the east side of the bridge. There was also the concern that if the phased construction approach was used, the weight restriction for the bridge would be further lowered and the fire trucks may no longer be able to use the bridge. However, no definitive numbers were given about what the weight restriction might be.
When asked how sure they were about the 35 times maximum for bridge closure, Vtrans explained that the contractor would be significantly penalized if they went beyond the 35 days and rewarded if they brought the project in under 35 days. The contractor would have the ability to run shifts 24/7 but activities creating significant noise would be done during the day and not at night.
In the next month, Vtrans will be finalizing recommendations for this project and the goal is to have a contract in place by Oct. 2013 with construction taking place in 2014, sometime after May 15.
A copy of the Scoping Report is available from the town office (226-7292), For those who would like to voice additional concerns about the proposed project, send them directly to:
Joshua K. Olund, P.E., Ph.D., Structural Engineer
12 Northbrook Drive
Building A, Suite 1
Falmouth, Maine 04105