Supercell-India

FAQ

SUPER CELL

Super Cell patented Super Cells are truly a revolutionary aspect of foundation piling equipment and pile capacity tests used today. Unlike conventional cells that are essentially the combination of a group of hydraulic jacks, Super Cells are inflated, and split the foundation pile unit into two parts. Each part can be measured with the other part as a reaction from the soil or rock system that the foundation is set in. They are able to withstand large pile and load capacities, and fulfill the current need for bi-directional load tests and pile load tests. They are easy to use, bear larger load capacities, and offer increased concrete flow and reliability.

Super Cells are made in flexible structures, and include (but not limited to) the following types:
* Donut-shaped Super Cell – Usually applicable to friction pile with max. 1.2m diameter.
* Multiple Super Cell – Usually applicable to large pile diameter (>1.2m) and large load, flexible combination.
* Solid Super Cell – Usually applicable to measure end bearing.

Advantages

Light weight, easy construction The Super Cell has a lightweight assembly, enabling it to be easily transported to and handled on site. It can be readily secured inside the rebar cage without the use of bearing plates.

Higher load capacities The Super Cell design utilizes a much greater cross-sectional area of the pile, enabling larger loads to be applied using the same low hydraulic pressures.

Improve concrete flow The Super Cell design incorporates flow guides, which can help to remove any risk of laitance build-up that may occur during installation. They also improve the concrete flow, at the cell location, and also between the upper/lower section of the pile.

Improved reliability The Super Cell is constructed entirely out of steel. An all-welded, hermetically sealed construction, where the cell’s increase in height is supported by expandable steel bellows. This feature removes the large sliding seals used by other BDSL methods, and allows for improved reliability of the fully sealed Super Cell.

SUPER CELL LOAD TEST

The new best way for testing pile load, improved method of static load tests and foundation load tests!

Bi-directional load test (or otherwise named Osterberg test or O-cell test) utilizes the hydraulically operated ‘Super Cell’ load cells, embedded within the concrete of the pile shaft for load and pile capacity testing. Before installing the foundation piles, soil investigation reports has to be done, to find the most optimal location for Super Cell installation.

The embedded Super Cells are specially designed with built-in Super-jacks. Hydraulic pressure is applied to the load cells by hydraulic pumps on the ground, through flexible hoses pre-installed along the reinforcement cages. The pressure in the load cell is measured by pressure gauges (pressure sensors); the displacements of the upper/lower parts of the pile shaft are measured by displacement transducers, which are connected to the load cell by embedded telltale rods.

When loaded, the Super Cell would expand and push the upper shaft upwards, and the lower shaft downwards. This sequence mobilizes the side resistance and base resistance of the upper and lower lengths of the pile. By analyzing the relativity between the movement and load force/time (S-lgt, s-lgQ curves, etc.) the carrying capacities of both upper and lower portions of the piles can be determined. The total carrying capacity of the pile can be found by adding up the modified side resistance of upward pile shaft, and the base resistance of downward pile shaft.

Advantages

Unlimited test load Any desired load force may be applied to fully mobilize the piles for testing when Super Cells are installed. The test load exceeds traditional pile load tests, static load tests, and foundation load tests.

Improved safety ‘Super Cell’ load cells are unlike other static load tests, reaction systems are not required. Large quantities of girder beams and concrete blocks are not used to eliminate base toppling – an improved safety feature the Super-Cell Super Cell has.

Limited work area required Next to existing buildings, under overpasses, highway median strips, and even offshore; much less space is required compared to traditional static load tests. Super Cells offer even more convenience for load test and pile capacity testing.

Time-efficient A considerable amount of time can be saved compared to static load tests with test blocks, since pile build up or strip down is not necessary. Promptly after installation, testing can be done.

Piles with deep cut-off levels For basement piles, load test can be performed below ground, eliminating the pile extension to ground level.

Test for working piles With advanced post-test grouting techniques, testing of working piles can also be done.

GEOTECHNICAL ENGINEERING

Geotechnical Engineering involves the application of soil and rock mechanics as well as engineering geology to solve engineering roblems such as design of foundations, retaining walls, slopes, excavations, dams, tunnels and other Civil, Mining and Environmental engieering projects relating to the mechanical response of the ground, and the water within it. Our geotechnical engineers have rich experiece in giving the most suited solutions for geotechnical problems and are well acquaint with almost every combination of rock, soil and ater known on earth.

Our expert professional team can perform complete soil investigation for all your needs, starting from planning, conducting field program, laboratory testing and finally report writing with recommendation. We add values to your project by providing expert geotechnical engineering service:

* Geotechnical Investigation
* Foundation design for infrastructures
* Pile foundation including static and dynamic load testing
* HDD for underground services
* Slope stability studies and Retaining wall design, including, geosynthetic reinforcement and structural systems
* Excavation shoring using soil nailing and other systems
* Soft-ground engineering and mitigation using wick drains, preloading, lightweight fill
* Geotechnical Instrumentation

FOUNDATION TESTING & EVALUATION

WAVE EQUATION ANALYSIS & DERIVABILITY ASSESSMENT FOR PILE FOUNDATION

In a most basic form, dynamic pile testing encompasses visual observations, measurement of the hammer stroke and pile penetration at the time of pile driving. In late 1930’s, engineers analyzed these measurements using energy formulations based on the Newtonion physics of rigid body impaction cushion stiffness, hammer stroke and other driving system parameters that optimize blow counts and pile stresses during pile driving.

Wave Equation Analysis of pile driving has eliminated many shortcomings associated with dynamic formulas by realistically simulating the hammer impacts and pile penetration process. It offers a rational means of establishing a relationship among the static capacity, stresses and blow count at the time of pile driving for a particular hammer in a given soil condition.

GRLWEAP computer program can be used to perform driveability analysis. A driveability analysis produces a safe prescription for pile installation, including recommendations on cushion stiffness, hammer stroke and other driving system parameters that optimize blow counts and pile stresses during pile driving.

HIGH STRAIN DYNAMIC PILE TESTING USING PILE DYNAMIC ANALYZER- PDA® (ASTM D4945) FOLLOWED BY CASE PILE WAVE ANALYSIS PROGRAM (CAPWAP®)

Dynamic pile testing and analysis are routine procedures in modern deep foundation practices. Dynamic Pile Monitoring is based on the Case Method of pile testing and is known as High Strain Method. It is covered by ASTM D4945 Standard Test Method for High-Strain Dynamic Testing of Piles.

Dynamic testing measures strain and acceleration near pile head under a hammer impact provides the basis for a complete analysis of the driving system-pile-soil condition. When the pile driving hammer impacts the pile top, accelerometers and strain transducers attached to it obtain data that is converted to velocity and force readings. Force and acceleration measurements taken near the top of a pile provide necessary information to determine:

* Mobilized pile capacity followed by further data analysis using CAPWAP
* Hammer performance
* Maximum driving stresses
* Pile integrity

During WEAP analysis various assumptions are made regarding hammer performance and soil parameters (available geotechnical information). These assumptions are verified using PDA and CAPWAP results; hence re-calibration of WEAP analysis is performed.

"... Before the project started, I was unconvinced that the use of PDA would be a cost-effective benefit to the project. It turned out to be well worth the cost as it frequently provided key evaluations at times when very costly situations required immediate decisions." Walter Grantz Chief Engineer of the Chesapeake Bay Bridge and Tunnel Project.

LOW STRAIN PILE INTEGRITY TESTING OR PULSE ECHO INTEGRITY TESTING - PIT (ASTM D5882)

The Pulse Echo Test, also known as Pile Integrity Test, Sonic Echo Test and Low Strain Test, is normally performed after pile installation and curing. Pulse Echo Integrity Testing is a non destructive pile testing method that evaluates the integrity of auger cast-in-place (CFA) piles, drilled shafts, driven concrete piles, concrete filled pipes and timber piles. It detects potentially dangerous defects such as major cracks, necking, soil inclusions or voids and, in some situations, can determine unknown lengths of piles that support existing bridges or towers.

If major defects exist, the test estimates their magnitude and location; it may also estimate pile length. The impact of the hand held hammer at the pile head generates a compressive stress wave in the pile, and an accelerometer placed on top of the pile monitors the motion associated with this wave. The stress wave propagates down the pile shaft, and is reflected when it encounters either the pile toe or a non-uniformity of the shaft. These reflections cause a change in the acceleration signal measured on the pile top, which is picked up and processed by the Pile Integrity Tester (PIT) equipment and interpreted.

It provides following benefits:
* Minimal Pile Preparation
* Simplicity
* Speed of Execution
* Low Cost
* Can be performed on 100% of the piles on a given job sit

QUALITY ASSURANCE AND QUALITY CONTROL

Third Party Quality Assurance And Quality Control

Although the Quality Control (QC) during the construction is preferable for the deep foundations, there are many instance when it is necessary to resort to Quality Assurance (QA) methods if, for various reasons, QC is not possible. Non destructive Testing (NDT) methods for the deep foundation are indirect approaches, i.e. in complex situations they do not provide complete information and need to be augmented by additional testing and/or analysis.

While the challenges are varied for the different deep foundation type and the different test methods they are the same in many different countries. Experience of the testing engineer is often mentioned as being most important for the best possible measurements and complete construction documentation for a meaningful data interpretation are minimum requirements for the successful test outcome. Another problem is the widely varying cost of the QA test. For that reason the specifying engineer or authority has to be aware of what can reasonably be expected so that technically feasible specifications can be written for optimal cost and minimal construction delays. QC and QA of deep foundations are much more difficult than other construction element because any potential defect are well buried deep in the ground.

Obviously, QA and QC are not free and the question often arise as to who bears the cost. Ultimately, all parties involved in a construction project benefit from a quality foundation and as such a certain amount of the funds should be available for monitoring and testing. Further, more progressive codes and specification allow reduced factor for LFRD, which reduced overall foundation cost and easily justify the testing cost.

"Our engineers working together in professional manner to get the center of the objective and develop the most adoptable solution. We strongly believe on human-centered approach to technology, is what makes the difference for your need."

GEOTECHNICAL INSTRUMENTATION

The engineering practice of geotechnical instrumentation involves a strong bondage between the capabilities of measuring instruments and the capabilities of engineers. There are two general categories of measuring instruments. First category is to use in situ, to determine the soil and rock properties i.e. permeability, compressibility and strength etc during design phase of the project. The second category is to monitor the performance, normally during construction phase of the project that may involve groundwater pressure measurement, stresses, deformation, load or strain etc. For major projects, an automatic data acquisition system helps in Real-Time Monitoring, Alert System and making the right decision which has impact on site safety.

We are equally experienced in designing instrumentation at designing stage and monitoring performance during construction phase. Our team is capable in the following type of geotechnical instrumentation.

* Vibratory Wire Piezometers/Standpipe Piezometers
* Settlement Cells
* Slope Inclinometers (SI)
* In-Place Inclinometers (IPI)
* Shape Accel Array (SAA)

Vibratory Wire Piezometers/Standpipe Piezometers: Piezometers are used to monitor the pore water pressures, which help engineers to determine initial site conditions, monitoring the effectiveness of drainage systems, determining safe rates for fill placement and ensuring slope stability etc. Multi level VW Piezometers can be used in series to monitor pore pressure at multiple zones or soil strata. VW Piezometers can be attached to the data logger and may be monitored remotely.

Settlement Cells: By using settlement cells, we can measure the vertical deformation in soil. This helps engineer to verify soil consolidation as plan, to correct or verify the rate of foundation loading, to verify the performance of engineering design and to determine the need and timing for corrective measures etc. Multi level settlement cells may be used to find the settlement among different zones or soil strata. Settlement Cells can be attached to the data logger and may be monitored remotely.

Slope Inclinometers: Slope inclinometers are used to monitor the lateral/subsurface deformations. This helps engineers to evaluate the stability of slopes/embankments, also performance and safety of structures can be verified. A special purpose, grooved pipe is installed in the borehole that passes through suspected zones of movement. Slope inclinometers are installed at toe/accessible places to get the manual readings.

In-Place Inclinometers: The mechanism of Slope Inclinometers and In-Place Inclinometers is same except that In-Place Inclinometer systems are used when continues monitoring is required for construction or safety. The system may consist of one or more dedicated sensors connected to data logger, hence can be monitored remotely.

Shape Accel Array (SAA): SAA is consisting of tri-axial MEMS (micro-electro-mechanical systems) gravity sensors. It can be used vertically to track magnitude and direction of lateral deformation and horizontally to track vertical deformation or settlement.

RESIDENTIAL COMMERCIAL INDUSTRIAL GRADING SURVEY

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General information on lot grading

WHAT IS LOT GRADING
By Lot grading, we mean sloping the land within a lot to direct the flow of surface water away from a building’s foundation. The sloping helps in directing water towards a suitable outlet where it can be discharged safely and according to the approved lot grading plan without negatively affecting adjacent properties.

PURPOSE OF LOT GRADING
* To ensure surface drainage away from structures;
* To provide for controlled surface drainage discharge points and rate of flow entering the public roads and storm sewer system;
* To minimize the amount of infiltration from surface run-off entering the sanitary sewage system

LOT GRADING APPROVAL REQUIREMENT :
At two stages during construction, the builder or homeowner is required to have the lot inspected for grading approval. To make sure the house and lot are constructed in accordance with all requirements, one should be familiar with the procedure for both the rough grade and final grade stages.

ROUGH GRADE STAGE
The rough grade stage is the responsibility of the builder. The lot is graded by the builder (contractor) to City/County requirements. Upon completion of the grading, the builder contacts an accredited Alberta Land Surveyor/Professional Engineer to survey the site and prepare and certify the rough grade certificate. Original copy of the rough grade certificate is submitted to the City/County for approval. Upon receipt of the rough grade certificate an inspection is conducted by the City/County's Lot Grading Inspector. If the inspection passes, a copy of the stamped approved grading certificate is sent to the builder or applicant.

FINAL GRADE STAGE
Final grade stage is the responsibility of the homeowner. Once the topsoil has been placed and grading completed (according to the applicable lot-grading guidelines), the homeowner must contact an accredited Alberta Land Surveyor/Professional Engineer to provide an as-built survey (or final lot grading certificate). Upon survey completion, Final Lot Grading Certificate fully stamped by Land Surveyor/Professional Engineer is submitted to the City/County for approval. Once received, a lot grading inspection is conducted by the City/County's Lot Grading Inspector. If the grading passes inspection, approved stamped copies of the grading certificate are sent to the homeowner (or the applicant). The homeowner is then able to proceed with landscaping the property. If the inspection fails, the homeowner is notified of the deficiencies (a new survey may be required) and a re-inspection can be scheduled upon correction of the deficiencies.

NOTE
These are general information regarding lot grading. For detail procedure, please read the instructions given on respective City/County web sites. For reference following are the web addresses of City of Edmonton, City of Leduc, City of Spruce Grove, Town of Beaumont, Strathcona County and City of St. Albert respectively.

http://www.leduc.ca
http://www.stalbert.ca
http://www.sprucegrove.org/services/permits_licences/lot_grading.htm
http://www.edmonton.ca/for_residents/flooding_sewers/lot-grading-approvals-residential.aspx
http://www.town.beaumont.ab.ca/pages.php?pg1=1005&pg2=2006&pg3=3006&pg4=4009 http://www.strathcona.ca/lot-grading-res.aspx

OTHER TESTING SERVICES

STANDARD PENETRATION TEST (SPT) ENERGY CALIBRATION

SPT is an in situ dynamic penetration test designed to provide information on geotechnical engineering properties of soil. The number of blows required to penetrate the last 12" is the “N value”, which is related to soil strength. The quality of the test result depends on various factors, such as actual energy delivered to the head of drill rod, dynamic properties of drill rod, the method of drilling and borehole stabilization. The actual energy is one of the factor which affects the reliability of SPT. Therefore as per codes, it is utmost important to check the performance of hammer periodically.

The Pile Driving Analyzer® (PDA) measures the energy transferred by the SPT hammer to the SPT rod which is instrumented with strain transducers and accelerometers gauges.

We perform this service in accordance with following standards:
ASTM D4633 : Standard Test Method for Energy Measurement for Dynamic Penetrometers
ASTM D1586 : Standard Test Method for Penetration Test and Split-Barrel Sampling of Soils,
ASTM D6066 : Standard Practice for Determining the Normalized Penetration Resistance of Sands for Evaluation of Liquefaction Potential.

BECKER HAMMER ENERGY MEASUREMENT

The Backer Penetration Test (BPT or Backer Drill Tests) is used in geotechnical investigation for coarse grained soils that are too hard to be tested with SPT. The test is particularly useful when liquefaction is concern in earthquake-prone areas. A diesel impact hammer drives a hefty double walled pipe into the ground. As in the SPT test, the number of blows required to drive the last 300 mm in record. This number is corrected to SPT blow counts to assess soil strength.

The energy output of the Becker Drill diesel hammer varies depending on the air-fuel mixture, temperature, pressure, soil resistance and hammer performance. In order to account for this variability, the hammer energy must be measured. The most reliable way to determine the energy is by force and acceleration measurement and processing by the Pile Driver Analyser®. For an accurate assessment to know how much of the resistance occurs at the pile toe. Only by knowing the end bearing component can the BPT blow count be reliably used.

Our engineers use Pile Driving Analyser to measure the energy transferred into Becker casing instrumented with strain transducers and accelerometers. Further analysis for the resistance distribution can be obtain by performing CAPWAP analysis.

This test is complaint with ASTM D4633-10 Standard Test Method for Energy Measurement for Dynamic Penetrometers.

ASTM D6066-96(2004) Standard Practice for Determining the Normalized Penetration Resistance of Sands for Evaluation of Liquefaction Potential.