The International Information Center for Geotechnical Engineers

The addition of a third structure, between the two existing bridge structures, carrying I-480 over the Cuyahoga River Valley near Cleveland, Ohio, required high pier loads and very deep foundations.

The Florida Department of Transportation (FDOT) initiated the construction of the new Little Lake Harris Bridge with the intention of conforming the bridge to meet current safety standards. GRL Engineers, Inc. was brought onto the project in December 2017, for dynamic pile testing and related service, as the specialty consultant member of the design/build team for the piling work.

 GRL performed a bi-directional static load test ("BDSLT") and provided Thermal Integrity Profiling (TIP) during the reconstruction of Russell Street Bridge in Missoula.

Tuesday, 15 May 2018 08:59

Static Load Testing by GRL

GRL performs both highly instrumented static load tests to meet the need of project design tests as well as basic load tests, for construction quality assurance.


SPT Energy Calibration consists of measuring the energy transferred by the Standard Penetration Test (SPT) hammer to the SPT rod. GRL Engineers take these measurements with the Pile Driving Analyzer® (PDA) and using an SPT rod instrumented with strain gages and accelerometers. GRL Engineers may also estimate soil setup by conducting a torque test on the instrumented SPT rod.

The Standard Penetration Test (SPT) is a widely used geotechnical test used to estimate soil strength. A SPT hammer drives a split barrel sampler at the bottom of a drive rod and recovers soil samples. The number of blows required to drive the last 300mm (12 inches) is the “N value”, and indicates soil strength. Several different types of SPT hammers are used to perform SPT tests, and this influences the N value.

The American Society for Testing and Materials (ASTM) recommends standardizing the measured N value by multiplying it by the ratio between the measured energy transferred to the rod and 60% of the theoretical potential energy of the hammer resulting in the N60 value. This compensates for widely variable efficiencies from different SPT hammer types and therefore improves the reliability of the estimates obtained from the test.

Source: GRL Engineers

The Deep Foundations Institute has announced that Dr. Frank Rausche, Ph.D., P.E., was selected as the DFI 2015 Osterberg Lecturer. Dr. Rausche will deliver this prestigious lecture on March 19, 2015 during the International Foundations Congress and Equipment Expo (IFCEE), with the theme “Load Testing of Deep Foundations: Developments, Applications, Results”.

Published in Other News

GRL Engineers has announced the opening of a Branch Office in Seattle Washington.   

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Over the course of the past several years GRL Engineers, Inc. (GRL) has introduced a series of six "APPLE" drop hammers. The devices are used in dynamic load testing of any type of deep foundation (ASTM D4945 Standard Test Method for High-Strain Dynamic Testing of Piles), in cases when a pile driving hammer or another suitable drop weight is not readily available at a job site. GRL has now added two more APPLES to the lineup. The APPLE VII is designed specifically to test helical piles. The APPLE VIII is a modular system with a maximum ram weight of 80 tons. That is double the maximum weight of the APPLE IV, previously the largest of GRL's drop hammers. With this addition, the APPLE devices now cover a large range of test loads, up to 8000 tons under ideal conditions.

The building that houses the headquarters of Pile Dynamics, Inc. (PDI) and GRL Engineers, Inc. (GRL) in Solon, Ohio, USA, is now LEED® Certified. The LEED program, established by the U.S. Green Building Council (USGBC) and verified by the Green Building Certification Institute (GBCI), is the United States preeminent program for the design, construction and operation of high performance green buildings. PDI and GRL are proud to be housed in the first - and so far only - certified LEED Green Building in the New Construction and Major Renovations category in the City of Solon.