- Site Characterization
- Pile Load Testing
- SPT Analyzer Testing
- Excavations and Shoring
- Slope Stability Analysis/Riverbank Stability
Site characterization is the first, and imperative, step to take prior to beginning design of any project that will ultimately go to construction. The objective of site characterization programs is to explore and sample the soil and groundwater conditions and assess variability across the site. Variability of subsurface conditions is not unusual but leads to potential project risks.
Our site characterization services include:
- Planning and implementing geotechnical investigations
- Supervising test hole drilling and collecting soil and bedrock samples for testing
- Soil classification and measuring groundwater conditions
- Observation of bore hole stability and groundwater seepage during drilling
- Installation and monitoring of geotechnical instrumentation
- Piezometers (standpipes, vibrating wire)
- Slope inclinometers
- Crackmeters and strain gauges
- Earth pressure cells
- Data collection
- Materials Testing
- Unified Soils Classification (USC)
- Moisture contents
- Unconfined compressive strength (UCS)
- Unit weight of Shelby tube samples
- Gradation analysis (hydrometer and sieve)
- Atterberg Limits
- Bedrock core sample logging
The design of foundations for structures needs to take into consideration the sub-surface conditions at the site, the type and magnitude of foundation loads (compressive, tensile, lateral, dynamic) and, in some cases, site constraints that limit the type of foundations that can be installed.
Our foundation engineering services include:
- Geotechnical site characterization
- Limit States Design and Working Stress Design
- Recommendations for design and construction of shallow foundations (footings, helical piles, thickened-edge slabs, rafts, mats)
- Recommendations for design and construction of deep foundations (cast-in-place concrete piles, driven piles, rock-socketed caissons)
- Recommendations for design and construction of underpinning piles
- Load-displacement (settlement) evaluation and down-drag assessment
- Numerical analyses (lateral loading of single piles and pile groups, wave equation analysis to evaluate driveability of piles)
- High-strain dynamic load testing (‘PDA testing’) with CAPWAP analysis
- Design of static load testing programs including bi-directional load cell testing for high capacity rock-socketed caissons
- Foundation installation monitoring
- Pile integrity testing
- Vibration monitoring
DRI has extensive experience with high strain dynamic testing (“PDA testing”) and CAPWAP analysis of driven pile foundations using the Pile Driving Analyzer® (PDA) equipment developed by Pile Dynamics Inc. Our experience includes timber piles, precast prestressed concrete piles and steel piles (HP and pipe) installed in a variety of soil conditions.
PDA testing is performed by attaching accelerometers and strain gauges to the sides of the pile to be tested and striking the pile with the pile hammer during initial driving to refusal or during a restrike test after the pile has been driven to refusal. The data collected during the test is used to evaluate the geotechnical capacity of the foundation. The data is also used to evaluate the pile driving stresses, pile hammer performance and pile integrity.
After the testing is completed, the data record(s) are analyzed using the CAse Pile Wave Analysis Program (CAPWAP®) to calculate the static geotechnical resistance and estimate the distribution of shaft and toe resistance. Piles can be re-tested to assess soil setup or relaxation effects.
In addition to traditional static load tests, DRI also has experience with bi-directional load testing programs and have designed testing programs for four project sites in Winnipeg, each site having two bi-directional load tests performed on full sized caissons. The results of this testing have provided valuable insight into the load-displacement characteristics and capacities of caissons socketed into limestone bedrock.
DRI’s geotechnical expertise has been trusted for major structures such as the True North Square development, Disraeli Bridges Project, RBC Convention Centre Expansion, Women’s Hospital Redevelopment Project, Manitoba Hydro’s Downtown Office Building and the James Armstrong Richardson International Airport Terminal Building, among other notable buildings.
DRI utilizes our Pile Driving Analyzer (PDA) equipment to perform dynamic testing of SPT hammers used by test hole drilling contractors to perform standard penetration testing. The SPT Analyzer measures the energy transferred into an instrumented SPT rod during a Standard Penetration Test (SPT) in accordance with ASTM D4633. The data permits the measured N-value to be adjusted to the normalized N60 for standard 60% energy transfer into the rods. Since there is widely variable efficiencies between different drill rigs and SPT hammer types, measuring the energy transfer for each drill rig improves the reliability of geotechnical design parameters determined from standard penetration testing.
Temporary excavations, including open cut excavations and shoring systems, are often required during construction due to the proximity of property lines to the project excavation limits and the need to protect surrounding infrastructure and property. The stability of temporary excavations is dependent on subsurface conditions, the size and depth of the excavation, and duration the excavation will be open.
Our services related to excavation and shoring include:
- Geotechnical site characterization
- Slope stability analysis
- Provide geotechnical recommendations for design of shoring systems
Slope stability is an important geotechnical consideration for temporary excavations and permanent structures such as bridges and buildings. In some cases, existing or proposed buildings may be situated near a riverbank or on a natural side slope.
DRI can provide the geotechnical engineering required to assess the stability of temporary excavations, riverbanks and naturally occurring slopes. Development offsets from riverbanks and natural side slopes are often required, and can be determined using slope stability analysis, to locate structures away from riverbanks/sideslopes so they will not be impacted by slope movements.