Cambridge Turnpike Improvement Project
Construction has continued during the COVID-19 crisis requiring the contractors to abide by the Governor’s March 23, 2020 Order regarding Essential Services.
Cairns & Sons completed the final paving on section 4 of CTIP Phase II on April 28, 2021. The phase II sections (Areas 2 & 4), constructed by Cairns & Sons, are substantially completed and are now under warranty until May 2022.
Project Identification Background
Cambridge Turnpike Improvement Project (CTIP) is one of the major projects going on in the Town of Concord. The project, as its name implies, is located on Cambridge Turnpike on the east side of Town focusing on the section of roadway from Routes 2 and 2A (Crosby’s Corner) to Lexington Road. This section of roadway traverses Mill Brook in two locations as identified on the map.
Portions of Cambridge Turnpike were originally identified as problem areas due to significant flooding from the rise in water elevation of Mill Brook during significant rain storms. The frequent road closures due to flooding were affecting the ability of the Town’s residents to use the road, especially the residents and businesses on the roadway. They had to deal with the flooding of their residences and facilities plus damage to their septic systems, the roadway, and the utilities in the road.
The Town, with recommendations from Concord Public Works (CPW) and the Public Works Commission (PWC) decided to undertake the CTIP to address the flooding, degradation of the roadway, and the associated utilities. The Town also decided to take this opportunity to integrate a multi-modal approach to the design of the new roadway. The design incorporated a corridor that is passable for motorists, pedestrians, and cyclists. The multi-modal improvements will complement the Town’s character and are in-line with Town initiatives to promote multiple means of transportation. Another important portion of the development is to protect the environmental and historical resources of the area while enhancing the experience of the residents using the resources.
Design and Permitting Background
To assist the Town in the challenges presented by the CTIP, Louis Berger Group (LBG) was selected by the Town and awarded the contract for the initial phase of project design. LBG came up with a conceptual design that addressed the roadway flooding, flooding of homes and businesses and the impacts to their septic systems, and roadway utilities. The primary design also included replacing and raising the two Mill Brook crossings by constructing a new bridge, new box culverts, and new retaining walls.
The Town with the assistance of the LBG Team implored involvement from the public/community and established a comprehensive public involvement program. The aim of this program was to acquire the concerns of the community and try to incorporate their input into the design. A questionnaire was provided to gather the community’s input. The information gathered was carefully considered in advancing the design to complete the draft Preliminary Design Report (PDR). After gathering the communities input the Town recognized that the community was also interested in the following:
- Environmental Impacts
- Traffic Safety and Intersection Congestion
- Roadway Width
- Historical Preservation
- Aesthetics - Landscaping, Structures
The public/community had additional opportunity to review the draft PDR and provide feedback to the Town which was incorporated into the design to the greatest degree practical. The PDR and subsequent design updates, along with Public Meeting information are available as links on this page.
The following was completed by LBG for the initial phase of the project:
- Flood study at the upper watershed of Mill Brook
- A site survey
- An initial evaluation of roadway and bridge alternatives
- Traffic studies and evaluations
- Conceptual intersection designs, and initial environmental permitting
Some information to note, as a result of the flood study the project team noticed that flood elevations for the upper Mill Brook watershed (from Main Street to Crosby Pond Dam) were too high, by approximately 3.5 to 4.5 feet for the 100-year flood. A Letter of Map Revision (LOMR) was filed with FEMA in order to correct the official flood plan elevation. A LOMR was issued by FEMA on August 16, 2015 to revise flood elevations for the Cambridge Turnpike area. These revised elevations were used as the baseline for the design, allowing the project’s impacts to be more accurately calculated to support the environmental permitting process.
After completion of the initial phase, the Town decided to advance the project to the development phase. CMA Engineers, Inc. (CMA) was selected by the Town and awarded the contract for advancing the CTIP through 100% design, permitting, project bidding, award, and provide resident engineering services during construction. Also during this time the Town contacted National Grid to inform them that significant construction was to be done on this roadway. Because of the flooding and the age of the gas main in Cambridge Turnpike, National Grid decided to replace the existing main. Additionally, the overhead electrical lines, telephone lines, and communication lines owned by CMPL, Comcast, and Verizon were to be relocated underground to the greatest degree practicable. This gas main and utility line replacement was incorporated into CMA’s design.
After the completion of the design and permitting, the Town and the CMA team decided to have the project bid as two separate construction contracts due to the unique requirements of each phase of construction. J. Tropeano Inc. was awarded phase I (identified as Areas 1 and 3 on the site map) of the contract, while George Cairns & Sons, Inc. was awarded phase II (Identified as Areas 2 and 4 on the site map). The construction was broken up in this way because Areas 1 and 3 were a more conventional roadway reconstruction while Areas 2 and 4 have to do with a bridge and large culverts to cross Mill Brook.