APPENDIX K CULVERT INSPECTION MEMO

Transcription

1 APPENDIX K CULVERT INSPECTION MEMO

2 McCORMICK RANKIN CORPORATION 2655 North Sheridan Way Mississauga, Ontario, L5K 2P8 Tel: (905) Fax: (905) Website: MEMO TO: FROM: Trevor Small, P.Eng. Chris Metaxas, E.I.T. DATE: November 2, 2009 COPIES: OUR FILE: SUBJECT: Introduction: Shahram Zavieh, P.Eng., Doug Dixon, P. Eng. Town of Milton / Halton Region ; Culvert Inspection McCormick Rankin Corporation (MRC) has been retained by Halton Region to complete the Class Environmental Assessment (Class EA) for the widening of Tremaine Road from Derry Road to Britannia Road in the Town of Milton. A part of MRC s Class EA assignment includes providing recommendations for the widening of the Tremaine Road culvert at Indian Creek, approximately 575m south of Derry Road. A visual inspection of the existing Tremaine Road culvert at Indian Creek was performed by two (2) members of MRC s structural department (S. Zavieh, P.Eng and C. Metaxas, EIT) on October 29, The purpose of the investigation was to assess the condition of the culvert and appurtenances, which may be incorporated into the widening of Tremaine Road, and assess site conditions. This memorandum has been prepared to document the findings of the visual inspection. Structure Description: The existing culvert is comprised of two lengths of 4200 x 1800 precast concrete box culvert sections separated by the east ditch of Tremaine Road. The west section of the culvert is perpendicular to Tremaine Road and was constructed in 1994 (see Photographs 1 and 2). The west section is 13.2 m long and comprises seven (7) units of equal length. The west section of the culvert was manufactured by Armbro (Lafarge) and labelled as a 4267 x 1829 precast concrete box culvert. Field measurements established that the culvert opening is 4280 x 1610 (reduced height measured due to sediment build up on the culvert bottom), with a top wall thickness of 405mm and side wall thickness of 305mm on the north and south walls. A 200mm high concrete head wall is located on the east and west ends of the west culvert. The water height on the day of the inspection was measured 1210mm from the soffit of the west culvert. The east section starts at the east limit of the Tremaine Road road allowance and extends 8.0 m easterly. The east culvert is comprised of five (5) units of varying length, ranging from 1220mm to 1930mm. The east culvert manufacturer could not be determined on site. The east culvert is Culvert Inspection Memo.doc

3 Memo To: Trevor Small Date: November 2, 2009 Page 2 labelled as a 4200 x 1800 precast concrete box culvert. Field measurements confirmed that the culvert opening is 4200x1670. A concrete retaining wall is located at the inlet (east end) of the east section. In general, the retaining wall parallels Tremaine Road, and connects to a berm and north and south of the structure. The east retaining wall is approximately 37.2m in length (measured along the face of the wall) and ranges in height (exposed) from 0 to 2.9m. Field measurements generally confirmed the design dimensions (G.D Jewell, July 2008), with the exception of the thickness of northern panel of the east retaining wall. The field measurement of 205mm is 32% less than the design dimension shown (300mm) on G.D. Jewell, Drawing S3 (July 2008). The east section of culvert, retaining wall and berm were constructed this year. The east section of culvert, retaining wall, and berm was designed for the Hawthorne Village on the escarpment, Phase 4 subdivision. Plans of the east culvert section, berm, and retaining wall are available, entitled Hawthorne Village on the escarpment, Phase 4 subdivision plan by G.D. Jewell Engineering Inc. for Mattamy Limited, Drawing S3, Project , July Plans of the west section of the culvert are not available. The gap between the east and west section of the culvert is 3.27m, which provides an inlet to the west section of culvert for the east side ditch of Tremaine Road. West Culvert Observations: In general, the west culvert was found to be in good condition, except for approximately 0.55m 2 of spalls on the inside soffit of the box culvert and wide gaps between the precast units. In addition, the spalls are located at the edges of the units and appear to be the result of rough handling with chains during installation. A summary of each units condition is described in the Table below. For record purposes Unit 1 is the located at the outlet (west end) and Unit 7 is located at the east end (inlet) of the west culvert section. Unit (Photographs) 1 2 (P3 & P4) 2 3 (P5 & P6) 3 4 (P7 & P8) 4 5 (P9 & P10) 5 6 (P11, P12 & P13) WEST CULVERT CONDITION Spalls / Delamination Staining due to Water Penetration 0.2m 2 spalls on soffit at Stains on soffit and gap between units; walls due to leaks at gap exposed reinforcing bar between units at spall. 0.05m 2 spalls on soffit at edge between units Stains on soffit and walls due to leaks at gap between units Gap between Units 10mm 15mm 10mm 15mm None. None. 15mm 30mm None. None. 30mm 50mm 0.1m 2 spall on soffit at edge between units. Stains on soffit and walls due to leaks at gap between units 25mm 30mm

4 Memo To: Trevor Small Date: November 2, 2009 Page 3 Unit (Photographs) 6 7 (P14, P15 & P16) WEST CULVERT CONDITION Spalls / Delamination Staining due to Water Penetration 0.2m 2 spalls on soffit at Stains on soffit and edge between units. walls due to leaks at gap between units Gap between Units 60mm 70mm at soffit tapering to 10 mm at floor. The gaps between the west culvert units were generally larger than the recommended tolerance (10mm). Grouting was present in the vertical joints between some units, however no grouting was present on the soffit between units. A summary of the grout locations is provided in the Table below. WEST CULVERT CONDITION GAP CONDITIONS BETWEEN UNITS Unit Grout Locations General Condition of Grout 1 2 North side full height of wall; Good South side full height of wall 2 3 North side no grouting; South side half height of wall Fair to Good (South side medium spall) 3 4 North side no grouting; South side full height of wall Fair to Good (South side small to medium cracking) 4 5 North side no grouting; South Good side 3/4 height of wall 5 6 None n/a 6 7 None n/a Other items noted during the inspection of the west culvert are as follows: The top surface of the culvert is buried approximately 400mm below the road and no distribution slab was found; Armour stone retaining walls are located at the west end (outlet) of the culvert; Gabion (wire basket) retaining walls are located at the east end (inlet) of the culvert. The bottom gabion basket at the northeast corner has a large hole and the rock fill is spilling out. The baskets also appear to be leaning to the east. See Photograph 17; The existing concrete box culvert was found to have approximately 300mm of fine sediment build up on the floor; Due to the depth of sediment on the floor slab we were unable to confirm whether or not cut-off walls were provided at the inlet and outlet; and A 200mm 300mm deep scour hole was noted at the west end of the culvert.

5 Memo To: Trevor Small Date: November 2, 2009 Page 4 East Culvert Observations: The east culvert was recently constructed (see Photographs 19, 20 and 21). In general, the culvert is in excellent (new) condition with no evidence of leakage, staining, delamination, or spalling. Other notable findings of the inspection of the east culvert are as follows: A minimum cover of 500mm was provided on the culvert, which is retained by an armour stone retaining wall/head wall at the west end and concrete headwall at the east end (see Photograph 19). The depth of cover rises uniformly to 1.0m at the east headwall; No sediment build up was noted on the bottom of the concrete box culvert. In addition, no river stone was noted as shown on the drawings by G.D. Jewell (July 2008); and Gaps between the units ranged from 10mm to 25mm. West Culvert Summary and Recommendations: The west culvert units are generally in good condition except at the unit edges, which appear to have been damaged during installation by rough handling. The installation of the units is also characterized by gaps between the precast units up to 70 mm wide. Some of the wide gaps have been filled with grout at the walls, but the wide gaps in the soffit were not grouted. In general, the grout is in fair to good condition. The leaks occurring at gaps between the units of the west culvert section is depositing chloride laden road drainage over extensive areas of the soffit and walls of the culvert. These leaks and ingress of chlorides into the concrete is expected to significantly shorten the remaining service life of the west culvert if no mitigation was undertaken. Also, the cover over the west culvert section is less than 600 mm, which indicates a distribution slab is required. However, no signs of distress due to load were evident. It is recommended that a distribution slab be constructed on the west culvert, which will seal the leaks at the gaps between the units, and improve the load capacity and durability of the structure. Roadside barriers comprise three-cable guide rail. Three-cable guide rail is not adequate roadside protection because this system deflects up to 3 m, which is well beyond the edges of the west culvert. Other recommendations include: removal of the existing three-cable guide rail system and replacement with steel beam guide rail with channel located a minimum of 0.6 m from the east and west edge of the culvert, to improve roadside safety;

6 Memo To: Trevor Small Date: November 2, 2009 Page 5 replacement of the gabion retaining walls at the east end of the culvert; and additional investigation to determine whether or not cut-off walls were provided at the inlet and outlet. East Culvert Summary and Recommendations: In general the east culvert is in excellent condition as it is less than 1 year old. We recommend that a guard in accordance with the Ontario Building Code be provided at the top of the retaining wall/headwall at the east end of the culvert for public safety reasons.

7 Photograph 1. West elevation of the West Culvert; facing north Photograph 2. Typical condition of the West Culvert panel; north wall McCormick Rankin Corporation November 2009 Page 1 of 12

8 Photograph 3. Condition of north wall joint between Units 1 and 2 Photograph 4. Condition of south wall joint between Units 1 and 2 McCormick Rankin Corporation November 2009 Page 2 of 12

9 Photograph 5. Condition of north wall between Units 2 and 3 West Culvert Photograph 6. Condition of south wall between Units 2 and 3 West Culvert McCormick Rankin Corporation November 2009 Page 3 of 12

10 Photograph 7. Condition of north wall between Units 3 and 4 West Culvert Photograph 8. Condition of south wall between Units 3 and 4 West Culvert McCormick Rankin Corporation November 2009 Page 4 of 12

11 Photograph 9. Condition of north wall between Units 4 and 5 West Culvert Photograph 10. Condition of south wall between Units 4 and 5 West Culvert McCormick Rankin Corporation November 2009 Page 5 of 12

12 Photograph 11. Condition of north wall between Units 5 and 6 West Culvert Photograph 12. Condition of south wall between Units 5 and 6 West Culvert McCormick Rankin Corporation November 2009 Page 6 of 12

13 Photograph 13. Spall on soffit between Units 5 and 6 West Culvert Photograph 14. Condition of north wall between Units 6 and 7 West Culvert McCormick Rankin Corporation November 2009 Page 7 of 12

14 Photograph 15. Condition of south wall between Units 6 and 7 West Culvert Photograph 16. General condition of West Culvert Unit 7; south wall McCormick Rankin Corporation November 2009 Page 8 of 12

15 Photograph 17. East elevation of West Culvert including north side gabion baskets Photograph 18. General condition of north spillway and ditch between culverts McCormick Rankin Corporation November 2009 Page 9 of 12

16 Photograph 19. West elevation of East Culvert Photograph 20. General condition of East Culvert; north wall looking east McCormick Rankin Corporation November 2009 Page 10 of 12

17 Photograph 21. East elevation of East Culvert Photograph 22. General site condition looking south McCormick Rankin Corporation November 2009 Page 11 of 12

18 Photograph 23. General site condition looking north McCormick Rankin Corporation November 2009 Page 12 of 12