And here is a study prepared by FOUR engineering firms for the Virginia Department of Rail and Public Transit...which pretty much completely disagrees with that self-serving ASCE fantasy.
http://www.dullesmetro.com/pdfs/LBT_PDF_Report_Only_02.26.2007_000.pdf
A brief extract:
Proposed Schedule
The LBT alternative has not been through the required public selection processes for consultants and bidders, environmental studies, public hearings, design completion and independent reviews, nor ongoing FTA reviews and sign-offs to be eligible for federal support. The 54-month project schedule indicated in the Proposal does not include these activities, nor does it incorporate the time required for additional drilling and geotechnical analyses.
In addition, the 54-month schedule is highly compressed. It is based on an overly optimistic average advance rate for the tunnel work and a 7-day work week. Using a more reasonable average advance rate and considering a 5-day work week produces a significantly longer construction schedule of 70 months. The 54-month schedule assumes concurrent tunneling activities for the stations, which represents a major risk to the proposed construction schedule.
Proposed Costs
The Proposal does not have a detailed, bottom-up cost estimate. It uses portions of the April 2006 estimate for the aerial alignment, which are not current. Therefore, the results cannot provide an “apples-to–apples” comparison of the aerial and large bore tunnel alternatives. The cost information provided indicates assumptions of contingencies of 15% for the New Austrian Tunneling Method (NATM) Tunnel and 10% for the TBM Tunnel, which are low for this stage of project design. In addition, using a more reasonable average advance rate could increase tunneling costs by 14%, not including additional escalation from the longer construction schedule.
The overall conclusion is that the proposed single-bore tunnel through Tysons Corner may be technically feasible; however there are significant risks that the construction costs and schedule durations stated by Tysons Tunnel, Inc. will be exceeded. Underground construction presents unique risks that are not typically encountered on other types of heavy civil construction. It is industry practice to evaluate any tunnel project’s viability within a risk-based framework. This has not been done for the Tyson’s LBT and it is not accounted for in Tysons Tunnel Inc.’s project planning and scheduling.
Additional findings are as follows:
1. The proposed single-bore tunnel through Tysons Corner appears technically feasible, although underground construction is considered higher risk than construction above ground.
2. There is sufficient information on the Proposal schedule to assess the overall proposed sequencing and some overall activity durations. However, at the Preliminary Engineering level, a much more detailed schedule would be expected.
3. There are significant risks that the project costs and schedule durations stated by Tunnel at Tysons, JV will be exceeded.
4. While substantial, the level of effort put forth by Tysons Tunnel, Inc. does not meet the 30% level of design completion for Preliminary Engineering of a project of this scale and complexity. While this level of completion accurately describes certain sections of the documents, such as architectural drawings, other sections such as utility relocation drawings are in a conceptual stage. As such, there are many questions and issues that must be addressed before these documents can be issued to the construction industry for bid.
5. There is a significant risk that the project cost of a Large Bore Tunnel would not meet the FTA’s Cost Effectiveness ratio criteria, which could compromise federal funding for the project.
6. FTA’s most recent written comment is “as we noted in our meeting in September 2006, there are scheduling and environmental review consequences that should be considered if the Commonwealth decides to undertake additional study of a tunnel option.” Once the large bore tunnel had completed all requirements to be fundable under federal guidelines in a minimum of 2 years, it could be considered for support.
7. The project design and construction program carry significant risks that need to be mitigated. While these can likely be addressed through additional subsurface exploration and testing, additional design, and additional construction planning, it is probable that doing so would cause the project cost and schedule estimates stated in the Proposal to be exceeded.
8. Given the many risks identified in the current project design and construction program and the inadequate geotechnical data, the contingencies incorporated in the Proposal’s cost and schedule estimates are unrealistically low.
9. The Proposal’s cost bases for non-tunnel components are out of date and incorrect.
10. The TBM advance rates upon which the Proposal’s cost and schedule estimates are based are unlikely to be achievable given the anticipated subsurface conditions. A more realistic advance rate and production schedule would increase tunnel construction costs 14% or more, and increase the overall project construction schedule of between 7 and 16 months.
11. There are questions about the appropriate tunnel technology for this project. Once geotechnical investigations are completed, determining the technology is more feasible.
12. The Proposal assumes the use of EPBM technology but a letter states reuse of one of the SMART tunnel machines, which are slurry machines. Due to the required increase in diameter for the Tysons tunnel, and a prior rebuild of these machines, a detailed review of the feasibility is needed.
13. The Proposal design is based on a number of assumptions that do not conform with certain WMATA and national standards. A number of the assumptions, if brought into conformance, would cause an increase to the size of platforms, stations, and possibly even the main tunnel, increasing construction costs and construction schedule.
14. There are a number of additional items in the Proposal, including Visual and Noise benefits, Right of Way costs, construction staging requirements at the two tunnel portals, and transit vehicle storage savings, with which the reviewers take issue. A number of these items could cause an increase to the Proposal’s stated cost and schedule, or both.
So feel free to shut the fuck up now...Mr. "I'm an Engineer Too"