patersongroup consulting engineers memorandum to: Stantec - Mr. Tim Wilkie - tim.wilkie@stantec.com re: Grading Plan Review Proposed Commercial Development - Kanata Commons Campeau Drive Extension - Ottawa date: December 15, 2014 file: from: PG0909-MEMO.05R David Gilbert Further to your request, Paterson Group (Paterson) prepared the current memorandum to provide the results of our grading plan review from a geotechnical perspective for the proposed commercial development at the aforementioned site. The following memorandum should be read in conjunction with Paterson Report PG0909-2R dated October 28, 2014. 1.0 Preload Pile Monitoring Program A permissible grade raise restriction of 1 m was previously recommended for grading within 6 m of the proposed buildings based on our in situ shear vane results and consolidation testing results. However, a soil preload program is currently underway at the proposed buildings, which have finished grades that exceed our permissible grade raise recommendations. The preload pile areas are outlined in Drawing PG0909-4 - Test Hole Location Plan attached. The preload pile was placed in 2010, however, settlement monitoring plates were not installed until February 2014. A summary of our settlement monitoring data recorded over the past several months is presented in Figure 2 - Preload Monitoring Program attached. It should be noted that the preload program did not include the future la-z-boy building, since the original grade at the future la-z-boy building location has been recently cut to the current grades and original ground surface elevations within the building footprint vary between 95.2 and 95.5 m. Therefore, the proposed grade raise is within our permissible grade raise restriction and preloading is not required for the la-zboy building. Based on the current grading for the site, the existing ground surface at Pile A and Pile B is approximately 0.7 m and 1.1 m, respectively, above finished grade of the proposed buildings in the immediate area. Based on survey information recorded at the settlement plate locations, settlement of less than 40 mm has occurred at the settlement plate locations within Pile A since February 2014. Negligible settlement has occurred at the settlement plate locations within Pile B since February 2014.
Mr. Tim Wilkie Page 2 File: PG0909-MEMO.05R Based on our settlement monitoring data for the preload program and available soils information, it is recommended that the preload program continue for Pile A to ensure that sufficient settlement has occurred before building construction begins. It is anticipated that the sufficient settlement will occur within the next 6 to 12 months to allow for conventional building construction. Alternatively, a lightweight fill program could be designed for the subject buildings to compensate for the grade raise exceedance. Based on our monitoring data to date, greater than 90% of primary consolidation for the underlying silty clay deposit has been achieved within the Pile B area. For design purposes, it is expected that total and differential settlements associated with the combination of grade raises and footing loading conditions will be limited to 25 and 20 mm, respectively. It should be further noted that conventional construction methods are acceptable and no LWF is required from a geotechnical perspective for the proposed building within the Pile B area. 2.0 Grading Plan Review Paterson reviewed the following grading plan prepared by Stantec for the aforementioned commercial development: Project 160400591, Drawing GP-1 - Grading Plan Interim Condition, Revision 3 dated December 4, 2014 Based on the grading plan provided and preload program currently underway, the grading for the following proposed buildings (The Brick, Unit 1 and La-Z-Boy), access lanes and parking lots do not exceed our permissible grade raise recommendations and are acceptable from a geotechnical perspective. Based on previous experience with similar developments, it is expected that the proposed service pipes will tolerate the minor settlement associated with the proposed grade raises and continue to function satisfactorily. Two options are available for approval of the proposed grading from a geotechnical perspective at the proposed Bank building and the proposed building housing CRU1 to CRU4: Continue the preload program until settlement levels have stabilized, which is estimated to occur within 6 to 12 months, or Place lightweight fill as detailed in Paterson Memorandum PG0909-MEMO.06 dated December 8, 2014.
Mr. Tim Wilkie Page 3 File: PG0909-MEMO.05R We trust that this information satisfies your requirements. Best Regards, Paterson Group Inc. David J. Gilbert, P.Eng Paterson Group Inc. Head Office and Laboratory 154 Colonnade Road South Ottawa, Ontario K2E 7J5 Tel: (613) 226-7381 Fax: (613) 226-6344 Northern Office and Laboratory 63 Gibson Street North Bay, Ontario P1B 8Z4 Tel: (705) 472-5331 Fax: (705) 472-2334 St. Lawrence Office 993 Princess Street - Suite 102 Kingston, Ontario K7L 1H3 Tel: (613) 542-7381 Fax: (613) 542-8399
Cumulative Settlement (mm) patersongroup Ottawa Kingston North Bay Figure 2 - Preload Monitoring Program Kanata Commons - Campeau Drive Extension 50.0 45.0 40.0 35.0 30.0 Plate 1 Plate 2 Plate 3 Plate 4 Plate 5 25.0 20.0 15.0 10.0 5.0 0.0-5.0 Time (date)