APPENDIX F. Structural Design Report

Transcription

1 APPENDIX F Structural Design Report

2 CONSULTANT SERVICES FOR AN ENVIRONMENTAL ASSESSMENT (EA) STUDY OF WHARNCLIFFE ROAD WIDENING FROM BECHER STREET TO COMMISSIONERS ROAD CNR SUBWAY BRIDGE REPLACEMENT STRUCTURAL DESIGN REPORT November 2017

3 TABLE OF CONTENTS 1.0 INTRODUCTION PROJECT LOCATION EXISTING BRIDGE BRIDGE ALTERNATIVES CONSIDERED Two Span Bridge Single Span Bridge Through Plate Girder Options MAINTENANCE OF RAIL TRAFFIC Option A Rail Diversion Track Protection Away from the Bridge Track Protection at the Bridge Track Protection for Installation of Retaining Walls Option B Trestles Soldier Pile Installation Trestle Installation Track Protection for Installation of Retaining Walls Cost Estimate Construction Duration Preferred Option FOUNDATIONS BRIDGE ERECTION Erection for Rail Diversion Option Erection for Trestle Option PROPOSED BRIDGE... 9 Wharncliffe Road Widening from Becher Street to Commissioners Road MMM Group Limited November CNR Subway Bridge Replacement i

4 9.0 ALIGNMENTS AND CROSS-SECTIONS Horizontal Vertical Vertical Clearance Cross Sections UTILITIES MISCELLANEOUS Design Code Protection System at Existing Bridge Access to Site Drainage SUMMARY AND RECOMMENDATION APPENDICES Appendix A Key Plan Appendix B Site Photographs Appendix C Preliminary General Arrangement Appendix D Rail Diversion and Track Protection Concepts Appendix E Trestle, Track Protection and Lateral Slide Concepts Appendix F Minutes from January 22, 2016 meeting with CNR Appendix G Cost Estimates Appendix H Schedules Wharncliffe Road Widening from Becher Street to Commissioners Road MMM Group Limited November CNR Subway Bridge Replacement ii

5 1.0 INTRODUCTION The City of London has initiated an Environmental Assessment Study for the Wharncliffe Road South widening project. The study area, as shown on the Key Plan in Appendix A, is the Wharncliffe Road South Corridor extending from Becher Street to Commissioners Road West. The City of London has retained MMM Group Limited (MMM) to undertake the Environmental Assessment Study. As part of the City of London s 2030 Transportation Master Plan, the recommendation was made to widen Wharncliffe Road South from Becher Street to Springbank Drive from 2 lanes to 4 lanes as well as the possible widening of the Canadian National Railway (CNR) Subway. This report focuses on the CNR Subway at Mile Strathroy Subdivision. This report documents the alternatives considered for replacement of the CNR Subway. In addition, recommendations for track protection and the final structural configuration are provided. For the purposes of this report, the bridge is considered to be oriented in an east-west direction. 2.0 PROJECT LOCATION The CNR Subway is located on Wharncliffe Road South immediately north of Horton Street in the City of London. It is located at Mile of the CNR Strathroy Subdivision. A key plan is provided in Appendix A of this report. 3.0 EXISTING BRIDGE The existing bridge is a three (3) span bridge, carrying two CNR tracks, supported on concrete abutments and steel bent piers. The main span is m and the end spans are 4.34 m. The floor system consists of transverse floor beams framing into three (3) longitudinal girders. The girders are of riveted steel construction consisting of plates for the webs and angles for the flanges. The railway ballast is retained with concrete in-fill between the floor beams. The steel bent piers are comprised of rolled steel columns at each of the girders braced with horizontal and diagonal bracing. The pier foundations appear to be mass concrete spread footings. There is a trainman s walk on the south side of the bridge. Existing ducts run along both sides of the bridge. Photographs of the existing bridge are provided in Appendix B. Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

6 4.0 BRIDGE ALTERNATIVES CONSIDERED 4.1 Two Span Bridge A two span bridge with spans in the range of 16 m to 24 m was initially considered. The issue with any two span bridge, irrespective of structure type, was that a centre pier would reduce the sight distance (compared to the single span alternative) for southbound traffic on Wharncliffe Road South. The desire from a road operation and safety point of view was to have a single span structure. As a result, the two span alternatives were not carried forward for further consideration. 4.2 Single Span Bridge The following single span bridge types were considered: a) Cast-in-place post tensioned concrete; b) Precast, post tensioned, concrete girders; c) Deck plate girders; and d) Through plate girders. For preliminary design purposes, a span length of 34.5 m was selected to accommodate the required cross section of Wharncliffe Road South. For a single span cast-in-place post tensioned concrete bridge with a 34.5 m span length, the required deck thickness is approximately 2.35 m. This would result in a substantial lowering of the grade on Wharncliffe Road South and Horton Street in order to meet vertical clearance requirements. Compared to a through plate girder bridge, the post tensioned concrete bridge would require an additional grade lowering of 1.5 m which would result in significant additional costs. In addition, the construction duration for the cast-in-place post tensioned alternative would be longer than the other alternatives. On this basis, the option of using a single span cast-in-place post tensioned concrete bridge was not carried forward for further consideration. A precast, post tensioned, concrete girder option would require the same thickness as the cast-in-place option. Therefore, the same issue with grade lowering to achieve the required vertical clearance is present. The ability to transport the girders was assessed and found to be problematic. Also, the ability to lift the precast girders into place is a concern; there would be limited options for crane placement with such heavy girders. As a result, the precast, post tensioned, concrete girder option was not carried forward for further consideration. A deck plate girder option was also considered. The required superstructure depth (below the bottom of the ballast) is 3.1 m. Compared to a through plate girder, the deck plate girder would require an additional grade lowering of 2.2 m which would result in significant additional costs. As a result, this option was not carried forward for further consideration. The through plate girder bridge would have the least thickness (below the base of rail) of all the alternatives considered. For preliminary design purposes, the thickness has been assumed to be 0.9 m Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

7 below the bottom of the ballast. This option would minimize the grade lowering of Wharncliffe Road South and Horton Street which would reduce the overall construction cost. As a result, the single span through plate girder option was carried forward as the preferred alternative. 4.3 Through Plate Girder Options The options for the single span through plate girder bridge that were considered are: a) Two separate single track through plate girder bridges; or b) One double track through plate girder bridge. The use of two single track through plate girder bridges would be more expensive compared to a double track through plate girder. The increased cost would be associated with a wider abutment and additional steel tonnage. In addition, there would be costs associated with changing the horizontal alignment to accommodate each of the single track through plate girder bridges (the track centre to centre spacing would need to increase). Due to these increased costs, the two single track through plate girder bridges were not carried forward. 5.0 MAINTENANCE OF RAIL TRAFFIC Two (2) options were reviewed for maintaining the rail traffic. The first option considered was to maintain railway traffic using a diversion. The second option considered was to maintain railway traffic on the existing curved alignment using trestles over the excavation for the new abutments (referred to as inplace construction). Both options may involve the installation of caissons and/or tieback anchors. The possibility of encountering old timber trestles buried in the railway embankment, used prior to construction of the current embankment, was identified during preliminary design. During detailed design, an effort should be made to locate the timber trestles through review of existing drawings and/or a ground penetrating radar survey. Locating any caissons or tieback anchors to avoid the remains of the timber trestles is recommended. 5.1 Option A Rail Diversion Conceptual sketches of the rail diversion and the required track protection have been provided in Appendix D. Reference to the sketch Sheet numbers has been provided in this section. For preliminary design purposes, it has been assumed that track protection will be required along Horton Street to retain the railway diversion embankment (see Section 3 on Sheet S3). Closer to the bridge, it has been assumed that a two sided track protection system is required to permit excavation for the new abutments (see Section 2 on Sheet S2). At Wharncliffe Road South, a two sided plug has been assumed for preliminary design (see Section1 on Sheet S2). The plug option would require the closure of Wharncliffe Road South for the duration of construction. Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

8 The option of using a temporary bridge at Wharncliffe Road South was considered. Wharncliffe Road South needs to be closed for a minimum period of approximately 6 months in order to complete the grade lowering on Horton Street. A detour bridge would allow Wharncliffe Road South to remain open during construction of the new bridge. One downside to keeping the road open is that the through plate girder superstructure would need to be constructed, in place, over traffic. There would be limited opportunity to stage traffic to avoid working directly over traffic. The cost premium associated with a detour bridge which would maintain traffic on Wharncliffe Road South, compared to a plug, was estimated to be approximately $425,000. The option of using the final through plate girder superstructure on the temporary alignment as a detour bridge and laterally sliding it into its ultimate location was also considered. The cost premiums associated with the temporary substructures and lateral slide for this option are $1,200,000 and $800,000, respectively. It is anticipated that the shoring for the detour alignment would be installed with CNR flagging, but without any track blocks. This should be confirmed during detailed design if the rail diversion is the chosen alternative Track Protection Away from the Bridge For the south rail detour, track protection is required away from the bridge to ensure that the proposed detour embankment does not encroach onto Horton Street. Solider piles with lagging and tiebacks have been assumed to be the method used for track protection (see Section 3 on Sheet S3). An alternative to solider piles with lagging is sheet piles. Sheet piles were not considered as a preferred alternative because an effective penetration depth, for resistance to lateral loads, may not be achievable in the dense native soils. The usage of sheet piles is discussed in the Geotechnical Design Report by Golder Associates dated December 2015 in Appendix I Track Protection at the Bridge At the bridge, the track protection concept developed during preliminary design is to use two shoring walls. See Section 2 and Plan on Sheet S2 for the conceptual details of this method. The north shoring wall would be installed first; temporary tieback anchors would be installed into the railway embankment. This would allow the material in front of the wall to be excavated. At this point, the south shoring wall could be installed and the horizontal anchors could also be installed. Then, backfilling of the detour and transferring of rail traffic to the detour could be completed. This would make the temporary tieback anchors redundant such that they could be removed and the new bridge could be constructed Track Protection for Installation of Retaining Walls It is envisioned that the retaining walls on the north side of the bridge would be constructed with rail traffic on the detour alignment. Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

9 For the retaining walls on the south side of the bridge and along Horton Street it is anticipated that rail traffic would be transferred back to the permanent alignment and that the shoring would be modified to allow for construction of the retaining walls. The retaining walls could be conventional reinforced concrete walls. Alternatively, permanent solider pile (with or without permanent tiebacks) and lagging walls with a concrete facing could be utilized. There may be some opportunity to utilize the shoring required for the detour alignment, along Horton Street, as the permanent retaining walls as well. This should be explored during detailed design. 5.2 Option B Trestles For this option, it has been assumed that a shoring system consisting of solider piles and lagging would be installed. Some of the solider piles would need to be installed from the existing railway embankment which would necessitate track blocks to complete the work. A temporary trestle would then need to be installed to maintain railway traffic while the permanent foundations and abutments are constructed under the active tracks. Further details on these components are provided in the following sections. Conceptual sketches for the track protection and trestle have been provided in Appendix E. Reference to the sketch Sheet numbers has been provided in this section Soldier Pile Installation It is anticipated that the soldier piles directly adjacent to the north and south track (lines 5, 6, 7, and 8 on the Plan on Sheet S4) would need to be installed with track blocks on one or both tracks. The remainder of the solider piles would be installed with railway flagging. The requirements for track blocks and flagging are outlined in Table 1 below. See Plan on Sheet S4 for the soldier pile numbering. Table 1 Anticipated Track Block and Flagging Requirements Soldier Pile North Track South Track A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4, Flagging D1, D2, D3, D4 A5, B5, C5, D5 Block (6 hrs. +/- per caisson) A6, A7, B6, B7, C6, C7, Block D6, D7 (6 hrs. +/- per caisson) A8, B8, C8, D8 Flagging A9, A10, B9, B10, C9, C10, D9, D10, E1, E2, Flagging E3, F1, F2, F3 Flagging Flagging Block (6 hrs. +/- per caisson) Block (6 hrs. +/- per caisson) Flagging Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

10 CN has previously confirmed that the existing train movement is 28 trains per day. Twenty two of these trains (passenger and freight) operate between 7:00 am and 11:00 pm. Six freight trains operate from 11:00 pm to 7:00 am. Approximately four passenger (VIA) trains operate in each direction each day. Both the north and south track need to be maintained for passenger trains with no interruption to service. Given the need to maintain the tracks for passenger trains, it is anticipated that daytime solider pile installation is not feasible. CN has previously confirmed that night (11:00 pm to 7:00 am) track blocks between 4.5 hours and 8 hours can be obtained with 6 weeks advance notice. The anticipated production rate for caisson installation is one (1) caisson per drill rig per night. It is anticipated that both tracks would need to be taken out of service for a total of 8 nights with one drill rig working. Alternatively, if two drill rigs were utilized, then both tracks would only need to be taken out of service for a total of 4 nights. For the remainder of the caissons, where only one track needs to be taken out of service, it is anticipated that a total of 8 nights is required if one drill rig was utilized Trestle Installation The total depth of excavation required to install each trestle is approximately 2.0m. Accordingly, the excavation required for trestle installation will extend into the influence zone for the adjacent track. Therefore, as a minimum, both trestles at one end of the existing bridge would need to be installed during a single closure period. CN has previously indicated that their preference is to install all the trestles during a weekend closure. A 36 hour closure has been previously suggested by CN (see minutes from January 22, 2016 meeting with CN in Appendix F). Ramps for access to the work area, for the permanent foundations, would need to be constructed at both the east and west abutments. It is anticipated that the access ramps would be installed on the north side of the bridge. The area available for access ramps on the south side of the bridge is more limited. See Sheets S5 to S8 for conceptual details of the trestle Track Protection for Installation of Retaining Walls It is envisioned that the retaining walls on the north side of the bridge would be constructed within the solider pile and lagging shoring system used for the trestle. For the retaining walls on the south side of the bridge and along Horton Street, permanent solider pile (with or without permanent tiebacks) and lagging walls with a concrete facing are recommended. An alternative to soldier pile walls would be to install a shoring system and construct cast-in-place walls. 5.3 Cost Estimate For the rail diversion (Option A) and the new bridge, the total estimated construction cost is $18,500,000 (including a 40% contingency). Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

11 For the trestle (Option B) and the new bridge, the total estimated construction cost is $15,600,000 (including a 40% contingency). A detailed breakdown of the costs for each option is provided in Appendix G. The unit prices utilized assume a base year of Any of the costs that CNR would pass along to the City, such as costs for railway flagging, are not included in the estimated construction costs. 5.4 Construction Duration For the rail diversion option (Option A), the estimated construction duration is 21.5 months. This excludes some paving and landscaping work which would need to be completed in favourable temperatures. For the trestle option (Option B), the estimated on site construction duration is 15 months. Gantt charts for Options A and B showing the critical activities are provided in Appendix H. 5.5 Preferred Option A meeting was held with CNR on January 22, 2016 to discuss the rail diversion and trestle options. CNR indicated that their initial preference is in-place construction using trestles (Option B). A copy of the minutes from the January 22, 2016 meeting is provided in Appendix F. 6.0 FOUNDATIONS A preliminary geotechnical report was prepared by Golder Associates which provides preliminary geotechnical recommendations (see Wharncliffe Road South CN Rail Bridge Replacement Preliminary Geotechnical Design Report by Golder Associates dated December 2015 in Appendix I). In general, the subsurface conditions at the site consist of the following layers: granular road base or topsoil, surficial layers of sand and silts, and an extensive stratum of silty clay. Glacial till was found in two boreholes close to the proposed bridge, at elevations ranging from m to m. The surface of the limestone bedrock was encountered in one borehole at an elevation of which is approximately 40 m below the existing ground surface. Groundwater was observed in the boreholes and measured in piezometers and found to be ranging from elevation m to m which is 1.9 m to 4.5 m below the existing ground surface. Spread footings or deep foundations (H Piles or Micropiles) were considered for this site. Spread footings were found to be impractical due to the relatively low bearing capacities of the Glacial Till and the depth of excavation required to found the bridge on the Glacial Till. For preliminary design purposes, deep foundations have been assumed. Micropiles have been assumed as the preferred foundation type on the preliminary general arrangement. Micropiles would allow the Contractor to complete the foundation work in a relatively confined area underneath a trestle using in-place construction techniques for the abutments. Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

12 The Preliminary Geotechnical Report indicates that H Piles or Micropiles would be founded in the very dense sandy silt glacial till below elevation 234 m to 235 m. This would result in piles which are approximately 5 m in length. 7.0 BRIDGE ERECTION The options for erection of the through plate girder bridge were reviewed during preliminary design. 7.1 Erection for Rail Diversion Option For the rail diversion option, conventional erection in-place is the most feasible and cost effective alternative. The bridge could also be moved into place using self-propelled modular transporters or by using a lateral slide approach. Either of these two options would be more costly, but would reduce the overall construction duration. 7.2 Erection for Trestle Option For the trestle option, a number of options for bridge erection were considered. The option of using cranes to lift the entire bridge into place, as a unit, during a weekend closure was reviewed. This option is not recommended due to the weight of the through plate girder superstructure and the limited area for the footprint of the large cranes required to lift the span. The option of using self-propelled modular transporters (SPMT s) to move the bridge into place, during a weekend closure (track block), was also considered. There would be a considerable amount of work that would need to occur to ensure a reasonably level surface for the SPMT s to drive on. During the weekend closure, this work would entail removal of the existing abutments/sidewalk and significant grading work. There would not be enough time, during a weekend closure, to complete this work and move the bridges using SPMT s. Therefore, the option of using SPMT s was not considered further. The option that is most feasible is to laterally slide the bridge into place, from temporary supports to the final position, during a weekend closure (track block). The bridge could be erected on temporary supports on either side of the existing bridge. There is more working area available on the north side of the existing bridge for cranes and construction equipment to erect the new bridge span on temporary supports. Based on MMM s assessment of the alternatives, we have concluded that the new bridge would be erected north of the existing bridge. To ensure appropriate vertical clearance to Wharncliffe Road South, the bridge could be built higher than the final required elevation and jacked down (prior to the lateral slide) using an incremental jacking scheme. See Sheet S9 in Appendix E for conceptual details of the lateral slide option. Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

13 8.0 PROPOSED BRIDGE The recommended new bridge consists of a 34.5 m through plate girder bridge with reinforced concrete abutments. The span length was determined such that the final configuration of Wharncliffe Road South can be accommodated. The width of the through plate girder bridge has been assumed to be 11.1 m (centre to centre of the girders). This will ensure that the standard railway clearance envelope can be achieved on the exterior portions of the bridge. It is recommended that the new bridge superstructure be coated and that galvanized bolts are used. This will avoid issues with rust staining of components below the bridge due to the use of atmospheric corrosion resistance structural steel. Coating and illumination may be used to improve the appearance of the finished bridge. The existing cross section of the north and south tracks is super-elevated due to the curved horizontal track alignment. The preferred alternative is to adjust the profile over the bridge such that the low rail for both tracks is at the same elevation. This would ensure that the bridge can be installed level. The steel plate girders can still be utilized if the existing configuration of superelevation is maintained. The assumed top of footing elevation is m (+/-) which has been set such that that the new sidewalks can be constructed. For preliminary design, micropiles have been assumed as the deep foundation solution. Wingwalls parallel to the railway alignment, 8.75 m in length, have been assumed for preliminary design. The use of an H-Pile foundation is an alternative to micropiles for the Rail Diversion option where headroom isn t an issue. During detailed design, the impact of any vibrations on the underground utilities would need to be confirmed. Retaining walls are required north of the new bridge along Wharncliffe Road South. In addition, retaining walls are required along the north side of Horton Street to avoid impacting the railway embankment. A preliminary General Arrangement is provided in Appendix C. 9.0 ALIGNMENTS AND CROSS-SECTIONS 9.1 Horizontal The proposed horizontal alignment for Wharncliffe Road South at the new CNR Subway is on tangent. The proposed horizontal alignment of the north and south CNR tracks is on an approximately 1 degree curve in the vicinity of the new CNR Subway. Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

14 9.2 Vertical The proposed vertical alignment for Wharncliffe Road South at the new CNR Subway will be a sag vertical curve with K = 8.00 and initial and final grades of approximately 3.6% (see Profile of Wharncliffe Rd on Sheet S1 in Appendix C). The vertical alignment for the north and south CNR tracks is proposed to be a crest vertical curve in the vicinity of the bridge. 9.3 Vertical Clearance The existing CNR Subway has a posted vertical clearance of 4.2 m. The minimum vertical clearance required under the proposed bridge is 5.0 m. 9.4 Cross Sections The proposed cross section for Wharncliffe Road South (see Elevation on Sheet S1 in Appendix C) is as follows: Variable width east sidewalk (minimum 2.0 m wide) 3.0 m boulevard Two, 3.5 m northbound lanes 1.5 m median 3.5 m southbound left turn lane Two, 3.5 m southbound lanes 3.3 m southbound right turn lane 3.0 m boulevard Variable width west sidewalk (minimum 2.0 m wide) The proposed cross section for the CNR tracks will not be changed from the existing cross section. Currently, the centre to centre spacing of the tracks varies and is approximately 3.92 m. The 11.1 m spacing of the girders, shown on Section 1 on Sheet S1 in Appendix C, will provide for a future track centre to centre spacing of 4.27 m UTILITIES There may be cables in the ducts running along either side of the existing bridge. They will need to be relocated off the existing bridge prior to commencing construction of the new bridge. There are buried sanitary and storm sewers under Wharncliffe Road South in the vicinity of the proposed CNR Subway. In plan, these buried utilities are outside of the limits of the new proposed bridge foundations. The use of micropiles will mitigate any impacts associated with vibration on the utilities that may have occurred with the use of conventional steel pile driving. Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

15 In addition, there are existing overhead utilities in the vicinity of the new CNR Subway which will be relocated prior to commencing construction MISCELLANEOUS 11.1 Design Code The design will be completed in accordance with the latest version of the A.R.E.M.A. Manual and CN Guidelines for Design of Railway Structures Protection System at Existing Bridge Depending on the selected staging configuration, a protection system at the existing bridge may be required in order to lower Wharncliffe Road South to the desired elevation Access to Site Access to the site would be via southbound or northbound Wharncliffe Road South Drainage The longitudinal grade of the bridge will be 0.5%. Horizontal drainage pipes shall be embedded in the ballast. The pipes will drain to the abutments and will be connected to a vertical drainage system behind the abutment walls SUMMARY AND RECOMMENDATION It is recommended that the new CNR Subway be built in place. This recommendation is based on the construction cost, construction duration, and CNR s preference. Trestles would be used behind the existing abutments to maintain railway traffic and allow for construction of the abutments. It is proposed to laterally slide the new CNR Subway into place from temporary supports constructed north of the existing bridge. It is recommended that the abutments for the existing bridge be cored vertically and horizontally prior to detailed design. This will allow the designer to confirm the thickness of the abutments, the presence of a footing, and the composition (i.e. rubble, solid concrete) of the abutments. In addition, the location of any shoring relative to the back face of the existing abutments can be confirmed by coring. Also, it is recommended that investigations of the embankments be undertaken for signs of timber bents (from old wooden trestles). Wharncliffe Road Widening from Becher Street to Commissioners Road CNR Subway Bridge Replacement MMM Group Limited November

16

17 APPENDIX A Key Plan

18 Key Plan CNR Subway

19 APPENDIX B Site Photographs

20 Photograph 1 South Elevation Photograph 2 Girders, Soffit and Floor System

21 Photograph 3 Northeast Wingwall Photograph 4 East Pier

22 Photograph 5 West Abutment

23 APPENDIX C Preliminary General Arrangement

24

25 APPENDIX D C Rail Preliminary Diversion Cost and Estimates Track Protection Concepts

26

27

28 APPENDIX E C Trestle, Preliminary Track Protection Cost Estimates and Lateral Slide Concepts

29

30

31

32

33

34

35 APPENDIX F Minutes from January 22, 2016 meeting with CNR

36 MEETING MINUTES Date of meeting: Friday, January 22, 2016 Location: Time: Purpose: CN Office 1 Administration Road Concord, ON L4K 1B9 10:30 a.m. Project: Wharncliffe Rd CNR (Strathroy Sub) Grade Separation Project Number: Author: Bob Rook To review and update CNR on the Environmental Assessment Study to Grade Separate the CN (Strathroy Subdivison) and Wharncliffe Road. Attendees: Title Company: Phone: Stefan Linder Manager, Public Works CNR stefan.linder@cn.ca (905) Vincent White Engineering Assistant CNR Vincent.White@cn.ca (905) Josh Ackworth Technologist, Transportation City of London jackwort@london.ca (519) x 7348 Doug Dixon Senior Project Manager, Structure MMM Group / WSP DixonD@mmm.ca (905) x 1236 Chris Suffern Project Engineer, Structure MMM Group / WSP SuffernC@mmm.ca (905) x 1527 Bob Rook, P. Eng., Senior Project Manager, Municipal MMM Group / WSP RookB@mmm.ca (905) x 1249 Distribution: All attendees above and the following: Ted Koza Transportation Design Engineer City of London tkoza@london.ca (519) x 5806 Michael Chiu Vice President MMM Group / WSP ChiuM@mmm.ca (905) x 1243 Gillian Thompson Project Manager MMM Group / WSP ThompsonG@mmm.ca (905) x 1285 Jay Goldberg Designer MMM Group / WSP GoldbergJ@mmm.ca (905) x 1284 Item Details Action By 1.0 Existing Condition Bob Rook provided an overview of existing conditions. Wharncliffe Road, a four lane urban roadway, north and south of CN crossing. At the CN structure, a 3 span structure provides an opening for a single lane northbound and two lanes southbound. Immediately south of the rail corridor is a major east/west four lane roadway, Horton Street. The intersection is signalized. Left turn movement from Wharncliffe Road onto Horton Street is not provided. Southbound left turn lanes turn onto Stanley Street while northbound left turn lanes turn onto Springbank Drive. Both streets are residential. Land use on Wharncliffe Road is a mixture of single family residential and commercial. The CN corridor has 2 main line tracks and carries approximately 28 trains per day. This includes 4 VIA trains in each direction. Vertical clearance at the underpass (road under rail) is substandard at 4.2 metres. Any omissions or errors in these notes should be forwarded to the author immediately North Sheridan Way, Suite 300, Mississauga, ON L5K 2P8 t: f: w:

37 Page 2 The City of London has acquired 3 residential properties, north of CNR corridor on the west side of Wharncliffe Road. Golder Associates have completed a geotechnical investigation for the grade separation project. A copy of the draft report was provided to CN (CD file). Wharncliffe Road is founded on layers of sand and silt, which is undertaken by silty clay and glacial till. The glacial till is very dense material. Limestone bedrock was encountered at 40m depth. It is expected that groundwater can be handled by pumping. Stefan Linder inquired if the project team was aware that fill embankments were constructed around timber trestle components which may be present in the rail corridor. MMM/WSP had received photos from their geotechnical consultant, Golders that identified the possibility of conflicts with the timber piles, if caissons or tie backs were installed through the fill embankment. Stefan will review CNR construction files. If necessary, a ground penetrating radar (GPR) investigation may be considered. Doug Dixon noted that it would be beneficial to have construction plans for the existing structure if CN is considering in-place construction. Coring of the abutments will still be required in the design phase of the project. Stefan Linder will review the availability of asconstructed bridge plans. 2.0 Preliminary Alternatives In the preliminary design phase, the project team reviewed 4 alternatives for Wharncliffe Road including two span and single span structures. East and west side widenings were considered along Wharncliffe Road. Copies of the preliminary options were provided in PDF. CNR CNR Wharncliffe Road would be reconstructed as a four lane roadway with left turn and right turn lanes at Horton Street. Provisions were provided for a future 1.5m on-street bike lane. Sidewalks are provided on both sides of Wharncliffe Road. Due to the proximity of Wharncliffe Road to Horton Street, the two span alternatives with a centre median pier was considered undesirable. The pier was a safety concern as well as restricting sight visibility. A single span structure is recommended. To minimize structure depth, a through plate girder bridge is proposed. Two alignments for Wharncliffe Road are still under consideration. The east side widening is recommended for in-place construction of the rail bridge. A west side widening is recommended if CN decides to construct a rail diversion. The road profile for Wharncliffe Road will result in a lowering of the existing road grade. At the rail crossing, a 0.8m profile lowering is required. At Horton Street, the lowering is 1.8 metres. 3.0 Track Profile Bob Rook noted that the City has completed a survey of the CN rail embankment including top of rail elevations (20m interval) from approximately 300m east to 300m west of Wharncliffe Road. Any omissions or errors in these notes should be forwarded to the author immediately North Sheridan Way, Suite 300, Mississauga, ON L5K 2P8 t: f: w:

38 Page 3 In reviewing the track profile, the rail tracks are in super-elevation. The Super-elevation is approximately 125mm. The track grade is relatively flat west of Wharncliffe Road. East of Wharncliffe Road, the track profile grade increases to 0.9%. At the rail structure, the track profile is locally depressed. To improve the vertical clearance (i.e. reduce road cut), MMM/WSP is recommending that the low rail for both tracks be the same. This will result in the floor beams being level and maintain a minimum ballast depth (400mm) under the low rail for each track. Opportunities are also available for a very nominal profile grade raise at Wharncliffe Road. An exaggerated profile (20:1 exaggeration) is provided in PDF. CN was requested to review the raising of the north track profile. 4.0 Horton Street Reconstruction Horton Street plan and profile was reviewed. The grade lowering extends from 200m west of Wharncliffe Road to 250m east of Wharncliffe Road. Horton Street will provide a four lane urban roadway with left turn and right turn lanes at Wharncliffe Road. Horton Street has been shifted to the south to minimize encroachment onto CN right-of-way. Immediately east and west of Wharncliffe Road, there is a nominal encroachment of the sidewalk into the CN right-of-way. This may be further reduced by reducing the boulevard width. CN was requested to review the feasibility of the sidewalk encroachment into the CN right-of-way. CNR CNR To maintain grading on the CN right-of-way, a retaining wall is required along the rail corridor. 5.0 Rail Diversion A preliminary rail diversion was developed on the south side of the CNR right-of-way. The existing track is presently on a continuous curve from ±300m east to ±700m west of Wharncliffe Road. The curve is approximately a 1.0 degree curve. To shift the rail track to the south, a tighter curve (1.75 degree) would be required. This may result in a lower design speed for passenger trains (i.e. 60 miles/h). Encroachment of the fill embankment on Horton Street would result in temporary track protection (shoring) to support the fill embankment. 6.0 CN Structure Doug Dixon provided an overview of the preferred structure general arrangement, which is a single span through plate girder (T.P.G.) supported on concrete abutments. The TPG structure will carry two (2) CNR tracks over Wharncliffe Road. The span length is 34.5m. The structure would be supported on piles, micropiles or caissons. The piles would be founded in the glacial till. The deposit exhibits end values ranging from 11 to greater than 100 blows per 0.3m. A very dense, grey sandy silt glacial till was encountered below the silty clay glacial till. Depth of pile is expected to be approximately 10m. Stefan Linder noted that trainmen walks would likely be required on both sides of the TPG bridge (to be confirmed). CNR Any omissions or errors in these notes should be forwarded to the author immediately North Sheridan Way, Suite 300, Mississauga, ON L5K 2P8 t: f: w:

39 Page 4 Doug Dixon noted that fiber optic cables were present on the existing rail structure and would be relocated. Temporary relocation options may include aerial relocation or supported in a U shape steel beam between the piled trestles. The cables would ultimately be enclosed in a duct structure and attached to the TPG. 7.0 Track Protection for Rail Diversion If a trestle system is proposed (i.e. build in-place alternative), micropiles would be used. For the rail diversion option, track protection details (Drawing S8) are proposed to support the existing railway embankment while excavating to install and support a continuous sheet pile or soldier pile wall. A second row of solider piles or sheeting would be installed with horizontal anchors to support the 2 track diversion. Golders report noted that driving sheeting to a suitable depth may be difficult in the dense till material. A soldier pile wall with shoring was detailed on Drawing S9 to support the widened fill embankment. 8.0 In-Place Construction Drawings S2 to S6 provides details for installation of concrete caissons for construction of soldier pile wall to support temporary trestles for each track at both abutment locations. Installation of caisson would require 8 night time closures (both tracks) for 8 hours. In addition, 8 night time closures of a single track for the remainder of the caissons would be required with CN flagging. For the trestle installation, MMM/WSP identified 2-12 hours closures (both tracks) at each abutment. Stefan Linder noted that his preference would be a longer weekend closure to complete the 4 trestles rather than 2 closures. (Suggested 36 hour closure, which includes CN removal and reinstatement of track). Doug Dixon noted that for the installation of the TPG superstructure, the project team reviewed a number of alternatives including lifting the superstructure in-place, sliding in place from a temporary concrete structure north of the permanent bridge (schematic S7) and transporting superstructure by rail and using Western Mechanical to slide in-place. The project team has reviewed the alternatives with Western Mechanical. Lifting in-place is not recommended due to the heavy load for a double track TPG and the limited work area for the size of cranes which would be required. The track closure time for a lateral slide alternative was estimated at 48 hours. Stefan Linder noted that his initial preference would be in-place construction. This would require agreement with CN Operations and Signals staff. Stefan will undertake a review with CN staff. Doug Dixon noted that MMM/WSP project team reached the same conclusion which is summarized in a comparison table between a rail diversion option and in-place construction. 9.0 Construction Staging Bob Rook provided an overview of a rail diversion and in-place construction schedule. The length of contract and road closure period for Wharncliffe Road was reduced for the inplace construction method. Any omissions or errors in these notes should be forwarded to the author immediately North Sheridan Way, Suite 300, Mississauga, ON L5K 2P8 t: f: w:

40 Page 5 Bob Rook noted that if the in-place construction was the selected method the east side widening alternative would be the preferred. This option would require relocation/removal of the private home at 100 Stanley Street. Josh Ackworth noted that this option may result in a Part II request in the EA process Stefan Linder noted that to respond to the preferred staging option, encroachment onto CN right-of-way and raising the track profile would take approximately 4 to 6 weeks for CN review Josh Ackworth noted that the City is proposing to proceed with construction of the grade separation in The 1200mm dia sanitary sewer that presently crosses the CN right-ofway along Wharncliffe Road would be relocated and the existing crossing abandoned. To abandon the sewer, the City would likely fill the sewer with grout. The City would review the schedule of both projects to minimize impact on Wharncliffe Road traffic Stefan Linder asked if the option of a jacked box would be considered at this crossing. Doug Dixon noted that the structure span would require a significant top slab depth, which would lower the road profile. This would have greater property impacts. City The foregoing represents the writer s understanding of the major items of discussion and the decisions reached and/or future actions required. If the above does not accurately represent the understanding of all parties attending, please notify the author within 48 hours of receiving these minutes at Minutes Prepared By: Bob Rook, P.Eng. Senior Project Manager Transportation Municipal Road Design 2655 North Sheridan Way, Suite 300 Mississauga, ON Canada L5K 2P8 t: x1249 f: c: RookB@mmm.ca Any omissions or errors in these notes should be forwarded to the author immediately North Sheridan Way, Suite 300, Mississauga, ON L5K 2P8 t: f: w:

41 APPENDIX G Cost Estimates

42 Part 1 Option A Rail Diversion Main Structure ITEM DESCRIPTION UNIT QTY PER UNIT AMMOUNT ROADWAY PROTECTION LS 1 $ 200, $ 200, EARTH EXCAVATION FOR STRUCTURE m $ $ 209, GRANULAR B BACKFILL TO STRUCTURE m $ $ 58, PILE DRIVING, MOBILIZATION AND DEMOBILIZATION LS 1 $ 70, $ 70, SUPPLY & PLACE HP310 X 110 m 648 $ $ 168, SUPPLY AND INSTALLATION OF CAST IN PLACE CONCRETE IN ABUTMENT FOOTINGS m $ $ 163, SUPPLY AND INSTALLATION OF REINFORCING STEEL IN ABUTMENT FOOTINGS t 32 $ 2, $ 70, SUPPLY AND INSTALLATION OF CAST IN PLACE CONCRETE FOR ABUTMENTS AND WINGWALLS SUPPLY AND INSTALLATION OF REINFORCING STEEL FOR ABUTMENTS AND WINGWALLS SUPPLY AND INSTALLATION OF COATED REINFORCING STEEL FOR ABUTMENT FOOTINGS, ABUTMENTS AND WINGWALLS m $ 1, $ 645, t 22 $ 2, $ 48, t 8 $ 2, $ 22, PERMENANT SOLDIER PILE AND LAGGING RETAINING WALLS m $ 2, $ 2,800, FABRICATION OF THROUGH PLATE GIRDER SPAN t 480 $ 3, $ 1,872, DELIVERY OF THROUGH PLATE GIRDER SPAN t 480 $ $ 216, ERECTION OF THROUGH PLATE GIRDER SPAN t 480 $ $ 465, COATING STRUCTURAL STEEL LS 1 $ 60, $ 60, SUPPLY AND INSTALLATION OF BEARINGS each 4 $ 17, $ 69, REMOVAL OF EXISTING STRUCTURE LS 1 $ 100, $ 100, WATERPROOFING OF BRIDGE DECK m $ $ 125, SUBTOTAL CONTINGENCY (40%) TOTAL $ $ $ 7,364, ,945, ,310,062.00

43 Part 2 - Option A -Rail Diversion - Detour ITEM DESCRIPTION UNIT QTY PER UNIT AMMOUNT EARTH EXCAVATION FOR STRUCTURE m $ $ 103, GRANULAR 'B' BACKFILL BEHIND SHORING WALLS m $ $ 184, SUPPLY & PLACE SHORING WALLS, C/W TIMBER LAGGING LS 1 $ 1,233, $ 1,233, TRACK & SHORING MONITORING LS 1 $ 50, $ 50, SUPPLY & PLACE 1200mm CHAIN LINK FENCE ON SHORING WALLS m 320 $ $ 35, SUPPLY & PLACE TRAINMEN'S WALKWAY $ - A) TRAINMEN'S WALKWAY FOR PRECAST CONCRETE SPANS LS 1 $ 20, $ 20, B) RAILING FOR TRAINMEN'S WALKWAY LS 1 $ 10, $ 10, GRADING WORK (RAILWAY EMBANKMENT, INSTALLATION OF TRACKS) LS 1 $ 4,000, $ 4,000, REMOVE DETOUR STRUCTURE AND CUT SHORING LS 1 $ 200, $ 200, SUBTOTAL $ CONTINGENCY (40%) $ TOTAL $ GRAND TOTAL PART 1 AND 2 $ 5,835, ,334, ,169, ,480,042.00

44 Option B - Trestle Option ITEM DESCRIPTION UNIT QTY PER UNIT AMMOUNT SUPPLY AND INSTALLATION OF TEMPORARY SHORING AND TRACK PROTECTION LS 1 $ 1,427, $ 1,427, ROADWAY PROTECTION LS 1 $ 200, $ 200, EARTH EXCAVATION FOR STRUCTURE m $ $ 135, GRANULAR B BACKFILL TO STRUCTURE m $ $ 57, SUPPLY, INSTALLATION, GROUTING AND TESTING OF MICROPILES m 920 $ $ 644, SUPPLY AND INSTALLATION OF CAST-IN-PLACE CONCRETE IN ABUTMENT FOOTINGS m $ $ 142, SUPPLY AND INSTALLATION OF REINFORCING STEEL IN ABUTMENT FOOTINGS t 28 $ 2, $ 70, SUPPLY AND INSTALLATION OF CAST-IN-PLACE CONCRETE FOR ABUTMENTS AND WINGWALLS SUPPLY AND INSTALLATION OF REINFORCING STEEL FOR ABUTMENTS AND WINGWALLS SUPPLY AND INSTALLATION OF COATED REINFORCING STEEL FOR ABUTMENT FOOTINGS, ABUTMENTS AND WINGWALLS m $ 1, $ 709, t 22 $ 2, $ 55, t 7 $ 2, $ 19, PERMENANT SOLDIER PILE AND LAGGING RETAINING WALLS m $ 2, $ 2,800, SUPPLY AND INSTALLATION OF TEMPORARY SUPPORT FOR THROUGH PLATE GIRDER LS 1 $ 1,179, $ 1,179, FABRICATION OF THROUGH PLATE GIRDER SPAN t 480 $ 3, $ 1,872, DELIVERY OF THROUGH PLATE GIRDER SPAN t 480 $ $ 216, ERECTION OF THROUGH PLATE GIRDER SPAN t 480 $ $ 465, COATING STRUCTURAL STEEL LS 1 $ 60, $ 60, SUPPLY AND INSTALLATION OF BEARINGS each 4 $ 17, $ 69, MOVE NEW BRIDGE INTO FINAL POSITION USING LATERAL SLIDE LS 1 $ 800, $ 800, REMOVAL OF EXISTING STRUCTURE LS 1 $ 100, $ 100, WATERPROOFING OF BRIDGE DECK m $ $ 125, SUBTOTAL CONTINGENCY (40%) TOTAL $ $ $ 11,148, ,459, ,607,620.00

45 APPENDIX H Schedules

46 Wharncliffe Road South CNR Subway Project Schedule Option A Rail Diversion WBS Task Start End Work Days 2019 Mar 2019 Apr 2019 May 2019 Jun 2019 Jul 2019 Aug 2019 Sep 2019 Oct 2019 Nov 2019 Dec 2020 Jan 2020 Feb 2020 Mar 2020 Apr 2020 May 2020 Jun 2020 Jul 2020 Aug 2020 Sep 2020 Oct 2020 Nov 2020 Dec 1 Grading Work on Horton Street & Installation of Detour 4-Mar-19 2-Dec Reconstruct and lower south side of Horton Street 4-Mar Jun Construct rail diversion, install shoring, reconstruct Horton Street Jun Oct Install track and ballast Oct Nov Transfer rail traffic to diversion Nov-19 2-Dec Construct New Bridge In Place 3-Dec-19 6-Aug Remove Existing Bridge Dec-19 9-Dec Excavation Dec Dec Drive Piles Dec Jan Construct footings Jan-20 6-Feb Construct abutments and wingwalls Feb-20 6-Mar Backfill Mar Mar Delivery of Steel Girders Mar Mar Install bearings Mar Mar Erect TPG Mar Jul Waterproofing Jul Jul Place subballast and ballast Jul Jul Install tracks Jul-20 5-Aug Divert rail traffic to new bridge Aug-20 6-Aug Remove Detour Alignment 7-Aug Sep Remove diversion Aug Sep Finishing Works 0-Jan-00 0-Jan Construct retaining walls on Wharncliffe and Horton Sep Dec Open Wharncliffe to Base Asphalt Dec Dec-20 1