Ottawa’s Light Rail

TransitProject

OLRT Tunnel Geotechnical UpdateTechnical Briefing

December 21, 2010

John Jensen

Director

Rail Implementation Office

Presentation Overview

• Background

• Preliminary Engineering Overview

• OLRT Project Review

• Geotechnical Investigations Rationale

• Geotechnical Investigations Update

• Questions

BACKGROUND &

OVERVIEW

Project ReviewFunctional Design

The functional design of the OLRT project (approved by Council January 2010) described a downtown tunnel that:

• Is approximately 3.2km in length with 4 underground stations

• Has a western portal located just east of Lebreton Station, near Brick Hill Street

• Has an eastern portal located just south of Campus Station, near Mann Avenue

Council directed staff to continue to refine the OLRT project design and seek cost savings where possible

Project ReviewAlignment

• The Rail Implementation Office (RIO) last provided its quarterly update to Transit Committee in September 2010

• At that time, RIO advised Committee that Phase 1 geotechnical fieldwork had been completed and that Phases 2 and 3 were scheduled for fall 2010 and spring 2011, respectively

Background

• RIO’s intent was to provide a geotechnical report with data and analysis once Phase 3 investigations were completed

• Due to expressed interest, RIO will provide the preliminary data set as provided by the firm chosen to conduct the geotechnical investigations, Golder Associates

• This presentation is to review the Phase 1 geotechnical data set

Background

Preliminary Engineering Overview

• The City selected Capital Transit Partners, a joint venture involving four firms with international expertise, to conduct OLRT preliminary engineering

• Jacobs Associates• Morrison Hershfield Limited• STV Canada Consulting Inc.• URS Canada Inc.

• The Preliminary Engineering work will advance the OLRT design and generate specifications for final design and construction and will be complete in Q1 2012

• Golder Associates has provided the Phase 1 geotechnical data to the preliminary engineering team and will continue as the selected firm to conduct Phase 2 and 3 investigations

Preliminary Engineering Advancing Design

• As a result of data gathering and advancing the OLRT project design, preliminary engineering staff are exploring several design modifications including:

• Locating tunnel’s east portal on the existing transitway south of Laurier Avenue, and situating Campus station on the surface in its current location instead of in the tunnel

• Shifting the ORLT alignment at Train station slightly northward outside of the Train station frontage area to allow for planned development and Highway 417 pedestrian bridge

• Remaining on the transitway alignment at Bayview station and simplifying the station and phasing its’ construction

• Once design modifications have been fully explored staff will present them to Council.

Project ReviewTimetable

TIMING PROJECT ELEMENT

January 2010 Approved Functional Design

May – August 2010 Phase 1 geotechnical investigation fieldwork

September 2010 Preliminary Engineering Commences

October – December 2010 Phase 2 geotechnical investigation fieldwork

April - July 2011 Phase 3 geotechnical investigation fieldwork

Q1 2012 Preliminary Engineering completed

2012 - 2013 Procurement process underway

2013 Construction Contract Award

2013 Construction Begins

2019 System in Service

GEOTECHNICAL INVESTIGATIONS

Geotechnical Investigations Rationale

• The purpose of geotechnical investigations is to obtain information necessary to understand engineering characteristics of the ground

• For a tunnel designer and builder, the ground conditions set the construction environment

• Understanding the ground’s engineering characteristics are as important as the concrete and steel used to construct stations

Geotechnical InvestigationsRationale

• In keeping with industry best practices, more thoroughly investigated tunnels have better cost and schedule certainty

• The geotechnical investigations for the LRT project are being undertaken in phases with each phase building on what was learned in the previous phase

# of Boreholes Drilling Reporting

Phase 1 34 May to August2010 December 2010

Phase 2 90 October to December 2010 April 2011

Phase 3 TBD(≈ 100)

April to July2011 November 2011

Geotechnical Investigation Schedule

Geotechnical InvestigationsUpdate

Geotechnical InvestigationsUpdate

• Phase 1 of the Geotechnical and Hydrogeological Field Investigation was completed in August 2010 and was confined to the tunnel alignment

• Preliminary data indicates that nothing has been encountered that would affect the technical feasibility of the project

Geotechnical Investigation Update

• West tunnel portal (west of Bronson) to Laurier Ave – fill, glacial till and bedrock

• Laurier Ave to East tunnel portal (near Campus station) – fill, silty clay, sand, glacial till and bedrock

• Bedrock consists mostly of limestone although some eastern sections are mostly shale

• As anticipated, a number of seismically inactive faults have been inferred from the boreholes

Geotechnical Investigation Update

• The results of this investigation are generally consistent with the ground conditions indicated in the functional design

• Some variations were encountered along the alignment south of Laurier Avenue, where the bedrock was generally deeper than assumed in functional design

• The specific locations where the ground conditions differ are subject to further investigation in Phases 2 and 3 of the geotechnical work

• Data from Phases 2 and 3 of the geotechnical fieldwork will be provided on the OLRT website when available in April 2011 and November 2011

Key Messages

The results of this investigation are generally consistent with the ground conditions indicated in the functional design

Preliminary data indicates that nothing has been encountered that would affect the technical feasibility of the project or the project cost estimate

All ground conditions noted to date can be accommodated using standard engineering practices and contracting strategies

The preliminary engineering team continues to adapt and refine the project design to match our knowledge of the ground conditions

www.ottawalightrail.ca

QUESTIONS?