Progress and Challenges

June 2005 - A brief history and review of pending issues

The Central Artery/Tunnel Project was conceived in the early 1980s. After being approved on a state and federal level, construction began in 1991. Over the years, both the scope of the project and its cost have grown, but the price has remained steady at $14.625 billion since Matthew Amorello took over as Chairman of the Massachusetts Turnpike Authority in 2002.  Despite the many improvements the "Big Dig" has already delivered to the motoring public, it's important to keep in mind that THE PROJECT IS STILL UNDER CONSTRUCTION.  

Accountability

In addition to taking steps to successfully contain the cost of the project and keep it on schedule, Chairman Amorello has required that designers and contractors that are responsible for any errors be held accountable for their work, insisting that they deliver what they are being paid to deliver and live up to all their contractual obligations.

In addition to overseeing and completing the CA/T Project, Chairman Amorello has also worked to restore credibility to the Project following the well-publicized non disclosure of increases to the Project cost in the late 1990s. As part of that effort, the Turnpike Authority has tried to be as transparent as possible in its oversight of the "Big Dig" taking such action as posting the Project Management Monthly (PMM) Reports on our website; and following the breach in the I-93 North Tunnel last fall, the Chairman committed to weekly press briefings/updates to keep the public informed of the progress with ongoing inspections of all the slurry wall panels.

The initial panel inspections are now complete, though some follow-up inspections continue. In a continuing effort to keep the public informed, however, the Chairman has directed the Project to offer updates on water infiltration - which is a separate and distinct issue from defective slurry wall panels - and to offer insight into other issues that need to be resolved on the Project before the MTA accepts the final work from the contractors. These updates will include water management indicator reports, which are sent regularly to the Federal Highway Administration and the U.S. Department of Transportation's Inspector General so they can monitor the Project's progress with water management, and other reports that help explain remaining challenges and progress as we work toward completion.  There are currently more than 1,000 punch list items to either complete or correct before the MTA accepts the final work from the contractor.

How issues are addressed

*When an area of concern is identified by Project personnel to be an issue tied to construction, the first course of action is getting the responsible contractor to take care of the issue and complete necessary work that will provide a lasting product that is in full compliance with their contract. We direct the contractor to do the necessary work, if they refuse, we bring in other contractors to do the work and backcharge the original contractors for the cost.  In instances where the area of concern is the result of errors or omissions during the design phase, and the designer will not agree to cooperatively devise corrective action and absorb any extra costs the Project has incurred, the issue will be referred for potential cost recovery.

Over the course of the last eight months, the issue of water infiltration in the Central Artery tunnels has been a matter of great interest and scrutiny. Water infiltration occurs in various locations within the tunnels and is attributable to a variety of issues - many of them expected as part of ongoing construction. In fact, a significant amount of the water being removed from the tunnels via our pump stations is the result of either active construction work or regularly-scheduled tunnel washing activity.

Remember, this IS STILL A WORK IN PROGRESS, and there are areas of active construction where the tunnel roof is not finished, allowing water to get inside. 

These include:
-The future on-ramp from Essex Street to I-93 North.
-The future South Station exit from I-93 South.

In addition, there are various areas along the downtown corridor where waterproofing remains to be done.  There are also conduit lines and manhole covers that haven't yet been sealed, which also generate a significant amount of the water infiltration which we continue to deal with as we work to complete the Project. Again, those avenues for water infiltration will no longer exist after the Project is completed.     

Background on water management indicators

It is important to keep in mind that there are two different issues which are talked about in our Water Management Indicator Reports.  One is water infiltration, which will be resolved as a final phase of construction.  The other issue is defective slurry wall panels, an unacceptable construction element; neither of these impacts the structural integrity of the tunnels. 

Slurry wall defects

First we look at the issue of defective slurry wall panels which we became acutely aware of after the breach of September 15 th  2004.  This event provided the footage of water pouring out of a tunnel wall, which has been a fixture on television newscasts for months. This was one of two breached panels in the 2,000 slurry wall panels in the I-93 tunnels, and by far the most significant.  To put this into perspective, the September 2004 incident produced about 250 gallons of water per minute, while the other breach had a flow of about 5 gallons per minute [it is important to note: we have 11 pump stations in the CA/Tunnel network and each station can handle an average of approximately 1,000 gallons per minute, so there was no concern of flooding from these incidents]. Chairman Amorello was outraged after the September breach and ordered a full inspection of all 2,000 panels to determine if there were additional issues.  During those inspections 167 other panels were found to have less serious defects, and ALL are being repaired. [The second panel deemed to be a breach occurred in January of 2004 when water on the roadway caused icing.  This event was not classified as "a breach" until the internal Project investigation that followed the September event found similarities between the two events.]  

The inspections of the slurry walls have been done by Bechtel/Parsons Brinckerhoff, the Project's Management Consultant at their time and their expense, and the panel repairs are being performed at the expense of the responsible contractor.

Water Management/Injection Grouting

The water management program deals with water infiltration which currently can be characterized as trickling and dripping. This is what has been alluded to in media reports saying the Project has "hundreds of leaks."  These areas are nothing of the caliber of the breached or defective panels talked about above, and grouting them is a normal part of construction. 

This year, as in past years, we have been conducting an inspection of the I-93 tunnels to monitor the progress of the Project's water management program.  More than 9,000 of the 9,500 [94%] roof girder bay ends [where tunnel walls meet the roof] have been inspected and 820 have been found to have wet [trickling or dripping] areas.  Since March 30 th the Project has been using the 820 figure as the baseline to measure the progress of the water management/grouting program and we will continue to do so during 2005.  As of the end of May that count has been reduced to 550 and while this is a good indicator of how the contractor's production/effectiveness is monitored, another yardstick is the volume of water entering the tunnels at these locations; the volume appears to be lessening as well with continued injection grouting and as additional sources of water related to construction such as open roof sections and conduit bays are sealed.  In addition to the wet areas there are more than 1,600 other roof girder bay ends where the 2005 inspection has shown what we refer to as "seeps" in our reporting and this means there is dampness [the Project criteria for classifying a roof girder bay end as seeping is: "Sheen is visible having a shining appearance, when wiped away, the sheen reappears, but no water is running or dripping"].  As grouting continues those damp areas that are near or against steel take priority over those that are not.  While "substantial completion" of road construction is slated for the fall of this year, the remainder of the work, which will include the injection grouting of some of these areas, will continue through the following months as has been planned.  This water management program is used to monitor the contractor's progress in meeting their contractual obligation in completing the grouting work.  *As noted in the section above: We direct the contractor to do the necessary work, if they refuse, we bring in other contractors to do the work and backcharge the original contractors for the cost.    

It is important to note that there will always be/and was always expected to be a water management element to the maintenance plan for the CA/T system, as there would be with any tunnel system, particularly those of slurry wall construction. 

 I-90 Tunnels

With regards to the I-90 portion of the Project, we are monitoring and inspecting areas in the Ted Williams and Fort Point Channel Tunnels as well.  In particular we have been monitoring an area near the Fort Point Channel since repair work was done after the tunnel opened in 2003.  Crack gauges were subsequently placed on a flexible pavement joint in that area to monitor its movement.  This past winter the joint expanded more than in the past, and this spring more water flow was found. It was determined the fix was not performing as anticipated.  The joint is too reactive to temperature changes, which have caused water infiltration and stress cracks in tiles and in a concrete column.  This is not a safety issue, as this column continues to perform its designed role. In fact, this column could be removed completely and it would not affect the structural integrity of the tunnel. 

Also on the I-90 portion of the Project we have experienced an inflow of approximately
4-8 gallons of water per minute at each of two immersed tube tunnel joints.   While this appears to be is less of an issue as the temperatures warm, a long-term solution is being developed to allow these joints to perform in the way they were expected to.  This water is piped directly from the two locations to a pump station.  The water is not on the roadway and is a very manageable amount for the pump station to handle.  That being said, while neither of these issues is one of safety, they are both UNACCEPTABLE and we will hold the responsible party or parties accountable to the full extent of their contract to insure these issues are resolved.