Abstract:
Pile quality verification engineering for drilled piles has traditionally been implemented by way of low tech and completely manual measurements, with a minimal number of recorded metrics such as drilled depth, toe elevations and inclination at the pile head only. Prior to production installation, test programs for piles are often limited to static load testing, with little consideration for the greater effects of construction methodologies of elements near or around the piles.
For some project scopes this may be sufficient, especially where foundations are greatly overdesigned with large factors of safety. However for projects with stricter tolerances, either due to budget considerations, high risk construction, or high value/high profile jobs, greater attention should be given to all aspects of the foundation construction.
The Parliament Hill Centre Block Rehabilitation Project in Ottawa ON is the largest and most complex heritage building rehabilitation project in Canada’s history. As such great care is being taken in all aspects of construction, including special attention to foundation design and construction. Hundreds of pipe piles are being installed using percussive drilling techniques, and conformance to specifications is extremely important due to the priceless nature and historical importance of Parliament Hill.
The purpose of this paper is to outline the advanced techniques being used to verify conformance to contract specifications, and how the information gathered can be used to inform future design decisions as the project progresses. Additionally, the paper presents the state of the art instrumentation and monitoring solutions employed to gather data during pile test programs.
With respect to pile quality verification, a summary of the techniques and equipment used to verify pile inclination direction and magnitude are presented. Methodologies for verifying threaded casing integrity and verifying the performance of post drilling construction steps are reviewed.
On test pile programs, topics include instrumentation types and installation techniques, data acquisition during test pile programs, and review of data with the implications for future design and construction mythology for the project. This includes instrumentation deployed along side traditional static load test techniques as well as custom instrumentation programs designed to monitor and assess the effect of related construction operations on the foundation piles through a mock pile test program.
Lastly, a discussion on the use and application of the techniques utilized on this project for future projects, and how these techniques assist in mitigating risk for the contractor/owner while providing avenues for value engineering and cost savings.