PROJECTS

The West Trunk Sewer Pipe (WTSP) is a 13.6 long tunnel, which runs mostly under Erin Mills Parkway in the City of Mississauga, Ontario. The permanent liner in the WTSP consists of 2,837m precast concrete segments, and 9,777m of 300mm thick plain concrete CIP liner. The CIP construction is complete and being coated with a chemical protective liner. The tunnel is 20 to 50m below ground level. 

 

The scope of work included the following:

• Perform site inspection of a 2,316m stretch of the Cast-In-Place (CIP) concrete liner between MH 5 and MH 6. The inspection has shown signs of structural distress in many areas along the CIP liner. The main cause of the structural distress in the CIP liner was the squeezing effects of the shale rock, where the flexural capacity of the plain concrete CIP liner was inadequate to resist the applied external pressure from the squeezing rock.

• Crack mapping and damage take-off.

• Strengthening of the CIP concrete liner using Carbon Fibre Reinforced Polymers (CFRP). A 2-layer composite system was designed to resist the applied tensile stresses at the inner face of the CIP liner. 

• Design of Glass Fibre Reinforced Polymer (GFRP) system to seal control joints and shrinkage cracks and prevent water infiltration to the tunnel. 

• On-site bond strength testing.

• Inspection of the CFRP and GFRP repair work. 

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During the warranty inspection of the Herridge Feedermain, many distressed pip segments were identified. In addition, some of the pipe segments which were strengthened in 2016 using Carbon Fibre Reinforced Polymers (CFRP) composite systems were found to fail in buckling due to inadequate pull-off strength of the deteriorated concrete. The structural strengthening work involved strengthening and renewal of additional 22 pipe segments. All pipe segments were renewed using stand-along CFRP systems. 

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The scope of work included the following:

• Perform site inspection of the CFRP repair work, which was carried out in 2016. 

• Perform pull-off testing of CFRP composites where signs of distress due to buckling were reported.

• Structural design of stand-alone CFRP systems to renew the deteriorated pipe segments.

• Testing of CFRP products to determine the long-term mechanical properties after 5 years in service inside the Herridge Feedermain. 

• Prepare of structural design drawings, design report, and as-built drawings.

• Final inspection and sign-off.

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The West Trunk Sewer Pipe is 13.6 km long, which runs mostly under Erin Mills Parkway in the City of Mississauga, Ontario, consists of two main sections. Section #1 extends from Manhole #1, Station 0+0 to Manhole #5, Station 3+387, with a total length of 3837 m. The liner in this section is made of precast concrete segments. Section #2, the CIP concrete liner, is 300mm thick, 2300mm clear inside diameter, and extends from Manhole #5, Station 3+837, to Manhole #12, Station 13+614, with a total length of 9,777 m.​

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The effects of Time-Dependent Deformation, different loading scenarios and mechanical properties of the rock medium were investigated through Analytical Method and Finite Element Method. The results of both analysis methods were compared for verification and compliance. 

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The scope of work included the following:

• Review of the available design drawings, geotechnical investigation, and project specifications related to the CIP liner.

• Review of the convergence pin monitoring reports. 

• Investigate the effects of different rock mechanical properties and water table levels on the internal forces in the CIP liner.

• Carry out structural analysis of the CIP liner and bedrock medium using analytical and finite element methods and compare the results for verification and compliance.

• Carry out the design check of the CIP liner.

• Structural assessment and recommendations for the current status of the CIP liner.

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A detailed design of the Carbon Fibre Reinforced Polymers (CFRP) work, required for strengthening of flat slabs in Defense Construction Canada (DCC) Office Fit-Up project, located in Ottawa, Ontario.  Many areas in the 5th, 6th, 7th, 8th, 9th, and 10th floors required strengthening due to change of loading conditions.

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The scope of work included the following:

• Carry out the structural design of the required CFRP system to reinforce the existing slabs as specified in the project’s specs.

• Prepare the shop drawings for the CFRP strengthening work.

• Coordination with other trades and site meetings.

• Construction follow-up, site visits, and inspection of the CFRP application.

• Final inspection and sign-off letter.

A detailed design of the Carbon Fibre Reinforced Polymers (CFRP) work, required for strengthening of the flat slab at the 6th floor of Dickson Building QEII in Halifax, Nova Scotia.

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Many areas in the flat slab at the 6th floor level required strengthening due to change of loading conditions. Opening were made in the flat slab for mechanical services, where some steel rebar were cut leading to loss in the structural capacities and required strengthening.

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The scope of work included the following:

• Carry out the structural design of the required CFRP system to reinforce the existing slabs as specified in the project’s specs.

• Prepare the shop drawings for the CFRP strengthening work.

• Construction follow-up and sign-off.

A vibration study for the Laundry Room in Basement 1 was carried out to determine the reasons behind the severe vibration in the floor slab when the 80 lb. washer extractor is run at a high extract speed.  

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Time-History dynamic analysis was carried out for the flat slab in Basement 1 to estimate the magnitude of displacement, velocity, and acceleration of the slab and compare it with the maximum allowable limits. Recommendations were given to reinforce the slab under the washer extractor in order to mitigate the vibration problem and reduce the magnitude of vibration to be within the acceptable limits.

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The scope of work included the following:

• Carry out site inspection of the Laundry Room to check the layout of the existing equipment and take site measurements.

• Review of the available structural design drawings and technical documentations of the washer extractors.

• Perform vibration study for the floor slab in Basement 1 under the effects of the dynamic loads exerted by the two 80 lb. washer extractors.

• Give general structural assessment of the main framing system and give recommendations for the required repair and strengthening measures to mitigate the magnitude of vibration and reduce it to the acceptable limits.

• Construction follow-up and sign-off. 

Structural design for CFRP renewal of Hamilton 1050mm Forcemain was required for the 42” in diameter mild steel Forcemain, running 248 m horizontally in a concrete tunnel and 48m in a vertical concrete shaft. The pipe is more than 50 years old, and used for the supply of potable chlorinated water at an average temperature of 23 °C. The pipe exhibits various degrees of steel corrosion and deterioration in its concrete saddles (supports). 

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The scope of work included the following:

• Carry out the CFRP design for the Forcemain as a stand-alone CFRP system.

• Perform a structural design check of the existing steel pipe.

• Carry out the CFRP design for the Forcemain as a composite system, where the CFRP laminate shares the host pipe in resisting the applied loads. Different extent of loss in the steel of the pipe wall shall be investigated.

• Give general structural assessment and recommendations for the required repair work including a rough estimate for the cost of CFRP renewal of the Forcemain.

The Odour Control Pipe (OCP) is a Reinforced Concrete Sewer Pipe, 1650 mm in diameter, 317.05 m long, buried in a clayey and sand-clayey silt. The top of pipe is approximately 1.0 to 1.5 m below existing grade level. Due to additional loads from the extra soil fill and the related traffic loads, and considering the deterioration in the existing RCP, Carbon Fibre Reinforced Polymers (CFRP) was considered as an option for the rehabilitation and upgrading of the OCP.

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The scope of work included the following:

• Review of available documents and drawings related to the CFRP design for the GE Booth OCP.

• Structural design of the CFRP liner as a stand-alone system to resist all the applied loads.

• Structural design of the CFRP liner as a composite system with the existing concrete pipe. 

• The design of CFRP liner as a protective coating against aggressive environmental conditions.

• Prepare design drawings, bill of quantity, and tender documents.

SIFTO Goderich Truck Scale # 1 is a more than 50 years old cast-in-place concrete structure exhibiting severe signs of concrete deterioration and corrosion of steel rebar. Structural design check of the main framing system was carried out in three phases:

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Phase 1: Site investigation and structural analysis of the structure as per the available design drawings

• Perform full structural analysis of Truck Scale #1 framing system based on the information shown in the available design drawings.

• Perform structural design check and code compliance of the framing system as per Ontario Building Code OBC-2012.

• Give general structural assessment of the main framing system and determine any vulnerable areas with high potential to be affected by concrete deterioration.   

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Phase 2: Investigating the structural capacity of the main framing system assuming different levels of corrosion in the reinforcing steel bars.

• Investigate the effect of an assumed 25% and 50% loss in the steel rebar area in all members of the main framing system.

• Perform structural design check and code compliance of the framing system as per Ontario Building Code OBC-2012.

• Give general structural assessment of the main framing system and determine any vulnerable areas with high potential to be affected by concrete deterioration.   

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Phase 3: Service life estimate of the structure after rehabilitation of the main framing system using Carbon Fibre Reinforced Polymers techniques

• Perform a site visit to check the “as-is” conditions of the main framing system in Truck Scale # 1.

• Carry out a design check for the Girders, Cross Beams, and the West Wall considering the installed CFRP systems.

• Give an estimate for the remaining service life of the main framing system.

The 1500mm Herridge Feedermain is a Prestressed Concrete Cylinder Pipe (PCCP), approximately 6 km long, exhibiting signs of deterioration and requiring rehabilitation. Based on the degree of deterioration, the renewal CFRP systems were designed either as a stand-alone or as a composite system with the concrete inner core of the PCCP.

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The scope of work included:

• Review of the design documents and specifications for CFRP strengthening work as a third-party peer reviewer.

• Investigation of alternate CFRP materials and feasibility study for the competent materials.

• Developing automated design tool for CFRP strengthening of beams and slabs as per AWWA standards and ASTM F1216.

• Preparing and issuing detailed reports and site instructions.

• On-site supervision and quality control of the application of CFRP material in the confined space environment.