Dutra Dredging Company
1000 Point San Pedro Road
San Rafael, CA 94901
415 721 2131

                                                          Serial Letter No. 0161

August 12, 1996

Department of the Army
San Francisco District, Corps of Engineers
333 Market Street
San Francisco, CA  94105-2197

Attn:   Thomas Benero, Contracting Officer

Ref:    Contract No. DACW 07-95-C-0003

Subject:  Sewer Line Crossing

Dear Mr. Benero:
As you are aware from conversations at our weekly meetings and various correspondence, the sewer line crossing as now described is rift with unknowns and potential hazards.

There are unresolved queries regarding valves, the recent discovery that there are two existing pipelines across the channel and the very serious issue of stability at the Union Pacific Intermodal Site. This last issue is the focus of this letter.

Attached you will find copy of the Union Pacific's hired geotechnical firm, Shannon and Wilson, Inc., review of the proposed installation methods and their concern regarding slope stability.

As a result of the S&W report and my own visual examination of the the proposed area at Union Pacific where the pipeline would come up the slope, we engaged a local geotechnical firm to do a preliminary investigation of slope stability and potential solutions. The report from that firm, GEI Consultants, Inc., is also attached.

Our conclusion is that the best solution to the slope stability issue is to move the location of the sewer line at the Union Pacific site some 500 feet east of the present location. There is approximately 50' of open land from the existing rails to the waterline which could allow open cutting of trench without slope stability concerns.

This approach would require about 650 feet of additional pipe. While pipe cost would go up, that will be less costly than trying to solve a slope stability issue at the present planned location.

Department of the Army
San Francisco District, Corps of Engineers
Serial Letter No. 0161
Page 2

Because this issue is so sever and complex, we believe that we all need to put together a group involving the Corps, contractor, railroad and Port of Oakland to come up with solutions to the issues as we know them.

The time is rapidly approaching when the pipeline crossing could become a critical item. With that sense of urgency, we request assistance. We are willing to participate in any forum which will expedite resolutions.

If there are questions, please contact us.


Robert D. Johnston


GEI Consultants, Inc.
Roger Foott Associates
565 Commercial Street
San Francisco, CA 94111
415 989 1262

August 8, 1996

Dutra Dredging Company
1000 San Pedro Road
San Rafael, California 94901

Attention: Mr. Bob Johnston, P.E.

Subject: Oakland Harbor Sewer Crossing Installation Alternative Sewer Alignment Commentary

Dear Bob:

Following our August 5, 1996 meeting with you and your Project Superintendent, Jeffery McWilliams, at the Union Pacific Intermodal Yard on the Oakland bank, we have reviewed the project information that your provided. The data included a copy of a July 24, 1996 letter from Shannon & Wilson to Union Pacific Railroad Company that contained comments on your proposed plan for installing the new sewer pipe under the railroad track and through the adjacent jetty rock fill. The Shannon & Wilson comments included the need for contingency plans because of the potential for undermining/removal of lateral support and loss of ground that could result in instability and/or settlement of the railroad tracks during the installation of the the proposed shoring system. They also questioned what would be done if large jetty rock prevented driving shoring members to required depths.

We agree with the expressed concerns and expect that the subsurface conditions at the site are not compatible with a risk-free installation as presently designed.


Mr. Bob Johnston                      2                      August 8, 1996

These conditions indicate the waterfront slope may not have a high degree of stability and the planned construction is very likely to cause ground movement, even when construction is carried out in the most careful manner possible.

We understand that you may submit a proposal to relocate the sewer crossing further to the east, where the railroad track curves away from the waterfront, to avoid the risks of damaging or weakening the railroad track foundation at the design location. This alternative location would eliminate the need for the shoring to be installed in the jetty rock and would probably eliminate the need for any shoring on the waterside of the railroad track. The casing would still need to be jacked under the railroad track from a jacking pit. The jacking pit would be constructed the same as your present design, but oriented and located differently.

The additional space between the jetty and railroad track would allow the waterside excavation to have sloped sides that would not threaten railroad track stability and that would allow the jacked casing to emerge into the sloped excavation. This would eliminate the problems of getting the jacked pipe through a steel bulkhead and the related potential for loss of ground.

A sketch of this scheme is attached. Our sketch is a conceptual plan is not intended as a design or construction drawing. This alternative would add to the length of the pipe and would require a longer jacked section.

Thank you for asking GEI to assist you on this project. Please let us know if you have any questions about this letter or if we can be of further service.



Roy A. Bell, P.E., G.E.

Attachment: Sketch of Alternative Oakland Harbor Sewer Pipe Crossing


GEI Consultants, Inc.

                                                 Project:  96231
Client:   Dutra Dredging                         Date:  8/8/96    By:  Roy Bell

Subject:  Oakland Harbor Sewer Crossing

    [This sketch shows the railroad vertical on the left side of the page in an
    East/West direction, and curves northward at the bottom half of the page.

    There is a line marked "Jetty" running East and West, on the South side of
    the railroad line, and is shown to be 15' from the South side track of the

    There is a "Jacking Pit" on the North side of the railroad with the South
    East corner of the pit shown to be 10' from the North side of the track at
    the approximate point where the track begins to curve Northward.

    There is another marking on the bottom of the page that seems to be
    identified as:  "Pipe ______ Harbor Crossing" and also "_____________ in
    about 10' deep ??/2:1 Side Slopes" - this seems to be another key aspect
    of GEI's conceptual design, but it is not clear what they have in mind.

    There is a note:  "This is a conceptual plan not intended to be a design
    or construction drawing."]

Geotechnical and Environmental Consultants
400 North 34th Street, Suite 100 [??]
P.O. Box 300309 [??]
Seattle, Washington 99103 [??]
206 632 6020 [??]

July 24, 1996

Union Pacific Railroad Company
Engineering Services Department
1416 Dodge Street, Room 1000
Omaha, Nebraska  68179-1000

Attn:  Mr. Kevan Ehrenreich [??]


We have completed our initial review of the geotechnical aspects of the above referenced shoring system. Documents provided for our review were an Executive Summary (2 sheets), Operation Plan (6 pages), Figure 1 (Oakland Bank Site Plan), figure 2 (Section E-E), and H-Pile/Plate Shoring Design Calculations (11 sheets). These were part of the report "-42-foot Navigation Improvements, Oakland Inner/Outer Harbor, Relocation of Navy Sewer Line, Permit to Construct Documentation for Union Pacific Railroad" prepared by Dutra Dredging Company (undated).

Based on this review, we offer the following comments:

  1. Section E-E shows a 42-inch diameter steel casing a telescoping sleeve and various angles for the pipeline to be constructed along the jetty slope.

    Firstly, Sections A-A and B-B that are located on Figure 1 were not included in the package and secondly the construction sequence of these casings and sleeve(s) particularly with regard to the connection at the shoring wall were not described in the Operation Plan (OP). Section A-A and B-B along the slope are necessary for our review in order to evaluate the potential impacts of the excavation on jetty slope stability. A more detailed description of the construction sequence for installing the sewer line within the jetty slope should be included in the OP. Items to be covered include: excavation slopes, bedding for the 42-inch diameter steel casing, bedding material gradation, telescoping sleeve construction, backfilling the casing and trench, backfill material gradation, and description of the connection between the slope steel casing and the horizontal steel casing beneath the railroad tracks, including the drawings of the connection.

Union Pacific Railroad Company                          SHANNON & WILSON, INC.
Attn:  Mr. Kevan Ehrenreich
July 24, 1996
Page 2

  1. There are no drawings, details or a description of how the jacked 42-inch casing pipe penetrates through the steel place shoring wall. How will loss of ground be prevented as the steel shoring plates are being cut for the steel casing?

  2. The calculations indicate that both a 30- and a 42-inch diameter steel casing will be used. The location and purpose of the two different size casings are unclear.

  3. Calculation sheets 8 through 11 illustrate a vertical HP section with turn buckles connected to the beam/plate shoring wall. The purpose of this system is unclear. More detailed cross section s including the casing(s) on both sides of the shoring wall and excavation grades should be provided. A construction sequence for this system is needed.

  4. The contractor should present contingency plans for maintaining slope stability if the wide flange beams can not penetrate through the riprap fill. It is understood that the large rocks will be removed prior to driving piles. Is there a plan if this initial rock removal results in slope instability and movement of the railroad tracks? What are the contingency plans if the steel sheets encounter obstructions above the base of the excavation? How will the plates be lowered or placed without causing loss of ground beneath the railroad tracks?

  5. We recommend the steel casing be backfilled along the slope above the rock jetty in accordance with Figures 11 and 12 (copies attached) from our January 1993 geotechnical report. The purpose of the backfill will be to prevent wave action from eroding fine material along the steel casing and beneath the railroad tracks.

  6. The earth pressures presented in the design calculation section are reasonable.
Shannon & Wilson, Inc., has prepared the attached "Important Information About Your Geotechnical Report" to assist you and others in understanding the use and limitations of our report.

Union Pacific Railroad Company                          SHANNON & WILSON, INC.
Attn:  Mr. Kevan Ehrenreich
July 24, 1996
Page 3

If you have any questions please call me at 206 633 6801.



Thomas M. Gurtowski, P.E.
Senior Associate


Enclosures:  Figures 11 - Typical Slope Protection Design Cross-Section
             Figures 12 - Transition Zone Grain Size Distribution
             Important Information About Your Geotechnical Report

Figure 11 Typical Slope Protection Design Cross-Section January 1993 W-6202-01 (???) Union Pacific Railroad Company Jetty Evaluation at T.O.F.C. Yard Oakland, California Shannon & Wilson, Inc. [Figure 11 shows a cross section as described above, including 3 foot thick rip rap layer an 2 foot thick transition layer.]
Figure 12 Transition Zone Grain Size Distribution Recommendations January 1993 ?????? Union Pacific Railroad Company Jetty Evaluation at T.O.F.C. Yard Oakland, California Shannon & Wilson, Inc.