STATRAPIDthe method of Rapid Pile Load Testing

Pile Load Testing

Allnamics is all about pile testing. With a wide range of testing techniques, Allnamics is capable to test any pile for its integrity, bearing capacity and stiffness. Being one of the pioneers in this field of pile testing, Allnamics founders, have contributed major knowledge to pile testing nowadays. Either Static, Dynamic or Rapid Load Testing. The latter is one of the innovations of Allnamics founders for pile testing. In 1990 the Statnamic method has been developed. Later followed by an alternative Rapid Load Testing: the StatRapid Load Test. That brings the total of testing techniques for bearing capacity to:
1. Static Load Testing
2. Bi-directional Load Testing
3. Dynamic Load Testing
4. StatNamic Load Testing
5. StatRapid Load Testing

All can be performed onshore as well as offshore.

RLT Statrapid Rostock
PDA Westermeerwind

PDA / PDM Pile Driving Monitoring

Foundation piles have been installed well since… well, Always! That implies Quality Assurance requires measuring during driving PDM or PDA (Pile Driving Monitoring or Pile Driving Analysis) to check the installation process e.g. pile stresses, blow counts and hammer performance. Both for impact hammers as vibratory hammers (VDM, Vibratory Driving Monitoring VDA Vibratory Driving Analysis).
After driving, the bearing capacity will increase in time (set-up). By measuring during a redrive, the static pile/soil behaviour and accordingly its static bearing capacity can be obtained by AllWave-DLT Signal Matching (DLT Dynamic Load Testing).

VDM / VDA – Vibratory Driving Monitoring

When piles are installed by means of a vibratory hammer, instead of an impact hammer, comparable measurements like with a PDM can be performed.
During Vibratory Driving Monitoring all information during installation are monitored, including performance and behaviour of pile, soil and vibratory hammer. Monitoring of pile stresses in relation to fatigue of the pile material, penetration speed, hammer frequency and efficiency, and more, are part of a total quality control for piles installed with a vibratory hammer. For foundations piles and large diameter monopiles. Onshore and offshore.

VDA Piletests
SLT paal met loadcell en vijzel Allnamics

SLT – Static Load Testing

Being the basis of all test, Allnamics performs static tests, both in compression and tension. Vertical, horizonal or under any slope.
With the equipment dedicated and designed for this type of test (see Allnamics Quad), high quality readings of load and settlements can be obtained.
The SLT is especially suitable for:
– Piles with relatively small capacity
– To determine design factors for shaft and toe resistance
– To determine load-displacement behaviour
– Trouble shooting

DLT – Dynamic Load Testing

After development started somewhere mid sixties, it was in the seventies and eighties of last century, that the Dynamic Load Test has been developed as a mature testing method. At that time offshore constructions were built for exploring oil at locations with, until then, unknown soil conditions. As an alternative for the Static Load Test, the Dynamic equivalent has positioned itself in the row of pile testing methods.

Allnamics founders are pioneers in this field. It all led to a series of monitoring systems starting with the FPDS (Foundation Pile Diagnostic System) up to Allnamics’ PDR nowadays.’
The mean reason to perform Dynamic Load Test is to obtain information about the pile behaviour during (static) loading. The Dynamic equivalent is much faster and less time consuming than Static Testing.

The application of DLT (internationally also known as PDA) is especially suitable for:
– Piles with high bearing capacities, where it’s hard to mobilise enough static force to load the pile statically up to failure, i.e. offshore piles
– Prefabricated concrete piles, able to resists the high impact stresses of the DLT
– Piles with a homogeneous cross section along the shaft
– Offshore and nearshore projects

For other piles, other methods are more suitable. For instance, applying DLT to cast in situ concrete piles, bored piles or CFA’s, the high impact loads leads to (too) high impact stresses with possible damage to the pile. Reduction of the impact load to limit the stresses to the concrete strength, leads for this type of piles to a low mobilised bearing capacity. Furthermore uncertainty in cross-section and concrete quality results in reduced accuracy of the analysis. These types of piles are preferably tested by Rapid Load Testing, StatNamic or StatRapid, for which which the maximum stresses during the test are significant lower.

PDA Bulgaria
RLT Utrecht

RLT – StatRapid Load Testing

Allnamics can choose to perform Rapid Load Tests with two different types of testing. For test loads up to 16 MN, StatRapid will be often used. For higher loads the Statnamic test method is available. With this test method loads up to 65 MN, and, in the near future, up top 150 MN, are possible.

Do you want to know more about StatNamic testing? Contact Peter Middendorp at middendorp@allnamics.eu

Bi-directional test (O-Cell)

The Bi-directional test is an alternative for the Static Load Test for bored concrete piles. Characteristic of this type of pile testing is that the load is applied somewhere halfway in the pile, instead of at the top of the pile.
By casting a device, the cell, into the concrete, somewhere halfway or near the pile toe, force and settlements at this level can be measured. The upperpart is pushed upward, being the counter force for the downward test load on the lower part. After the test, the measured results are used to construct the load-settlement graph comparable to that of a Static Load Test.
The Bi-directional test will be applied for piles with higher capacities, with significant shaft friction to mobilise enough counter force to mobilise the shaft and toe resistance of the lower part.

Sisterbars for RLT Sonate Allnamics
SIT-USB Testing Allnamics

Pile Integrity Testing (Sonic Integrity Testing)

The Sonic Integrity Test has been developed by the engineers of Allnamics, in the seventies of last century.
The test determines imperfections in concrete piles: Cracks, changes in cross sectional area, soil inclusions, voids and other imperfections.
The Pile Integrity Test or Sonic Integrity Test is the first, fast and rough, check on the quality of cast in situ piles.

Sonic Logging

Sonic Logging is performed by lowering sensors in cast in tubes. By sending a sonic signal through the concrete by the transmitter to the receiver, information about possible defects and concrete area over the cross sectional area will be obtained.
Sonic Logging is mainly used for bored piles with large diameters and diaphragm walls.

Piletests

PAPERS AND ARTICLES

Allnamics has made many contributions to international conferences. These publications are available via the Allnamics database. A selection can be found below:

Static and Dynamic Load testing of steel tubular piles in chalk for the offshore wind farm Baltic 2

Probebelastungen von Stahlrohren in Kreide für den Offshore-Windpark Baltic 2 Auteur(s): MBA BSc Thomas Lahrs Dipl.-Ing.; Kurt Fredrich Year: 2013 Language: German Where: Pfahl-Symposium 2013, Braunschweig, Deutschland INTRODUCTION: Die EnBW Erneuerbare Energien GmBH, Hamburg, plant in der südlichen Ostsee die Errichtung des offshore-Windparks Baltic 2 mit 80 Anlagen der 3,6 MW-Klasse. Das Bau-feld befindet sich […]

Re-evaluation of the method to determine pile damage using the Beta Method

Auteur(s): G. Verbeek; G. Goble Year: 2012 Language: English Where: Proceedings of the IS-Kanazawa, Japan INTRODUCTION: In 1979, a paper was published by Rausche and Goble describing a method to determine damage in driven piles using the Beta Method. Over the years this method has become the standard for pile damage assessment in many parts […]

Pile foundation testing of a hurricane resistant jetty

Auteur(s): Middendorp, P., Plooy, P.J., Kruit,D.B Year: 2008 Language: English Where: 8th Int. Conf. Application of stress-wave theory to piles, Lisbon INTRODUCTION: To prevent pile driving problems during the construction of a jetty at Grenada a proof testing approach was applied whereby test pile driving was performed at several places where the jetty was to […]

At the cutting edge of pile driving and pile testing

Autor(s): Middendorp, P., Verbeek, G. Year: 2012 Language: English Where: 9th International Conference on Testing and Design methods for Deep Foundations; Kanasawa, Japan INTRODUCTION: The worldwide challenges to achieve a greener planet, better communications, cost effective and fast means of transportation, and the protection against natural hazards (such as earthquakes, floods, tsunamis and hurricanes) continually […]

Tailor made solutions for the realization of pile load tests under water

Maßgeschneiderte Lösungen zur Realisierung von Pfahlprobebelastungen unter Wasser Auteur(s): Merzenich, Benecke, Fischer Year: 2015 Language: German Where: Pfahlsymposium INTRODUCTION: Der spanische Energiekonzern Iberdrola ist derzeit in der Planungsphase des Offshore-Windparks (OWP) Wikinger in der Deutschen Ostsee. In Wassertiefen von ca. 40 m sollen 70 Windturbinen über Jackets und Pfähle fest im Meeresboden verankert werden. Zur […]

Modeling and Observations of Pile Installation using Vibro Hammers in Fraser River Delta soils

Autor(s): David Tara, Peter Middendorp, Gerald Verbeek Year: 2014 Language: English Where: Modeling and Observations of Pile Installation using Vibro Hammers in Fraser River Delta soils INTRODUCTION: There has been significant recent interest in the use of vibratory drivers/vibro hammers to install piles in offshore and nearshore applications around the globe. Recent experience using vibratory […]

Pile Driving Analysis & Vibro Hammers A Viable Combination

Autor(s): Verbeek G.;Middendorp P.; van Dorp R.; Tara D. Year: 2013 Language: English Where: Presentation SuperPile 2013, Minneapolis, MN INTRODUCTION: Presentation held at the SuperPile 2013 conference in Minneapolis, MN DOWNLOAD: You can download the entire article here, after entering your name and e-mail address. .

Installation of Monopiles by Vibrohammers for the Riffgat Project

Autor(s): L. de Neef, P. Middendorp, J. Bakker Year: 2013 Language: English Where: Pfahlsymposium, Braunschweig INTRODUCTION: The successful installation of 22m diameter steel tubular piles/caissons by vibratory hammers in China in 2011 resulted in a strong interest in the application of vibratory hammers to install steel tubular monopiles for wind turbines, especially offshore. The first […]

Skin friction models for sand from static and dynamic laboratory load tests

Auteur(s): Middendorp,P., van Brederode, P.J. Year: 1984 Language: English Where: 2nd International Conference on Stress Waves, The Hague, Netherlands Proceedings INTRODUCTION: The behaviour of a foundation pile during impact loading can be measured or it may be simulated by computerized calculation. Although today measuring techniques and computer algorithms have reached high levels of accuracy, the […]

A digital approach to sonic pile testing

Auteur(s): Reiding, F.J., Middendorp, P., P.J. van Brederode Year: 1984 Language: English Where: 2nd International Conference on Stress Waves, The Hague, Netherlands Proceedings INTRODUCTION: Paper regarding digitizing of SIT measurements. DOWNLOAD: You can download the entire article here, after entering your name and e-mail address .

Hydroblok and Improved Pile Driving Analysis

Auteur(s): Voitus van Hamme, G.E.J.S.L. Jansz, J.W. Bomer H.,and Arentsen, D. Year: 1974 Language: English Where: De Ingenieur Vol. 86, no. 8 INTRODUCTION: In a previous article, a description of a number of features of the Hydroblock has been given, in particular, the properties of the hydroblock have been compared with those of other types […]

Rapid Pile Load Testing in Barcelona

Pruebas de carga rápida de pilotes en Barcelona Auteur(s): Moscoso del Prado Mazza; Fernández Tadeo; Bielefeld; Year: 2018 Language: Español Where: Obras Urbanas sept – oct 2018 nr 71 INTRODUCTION: The first Rapid Load Tests in Spain were conducted in 2017 in the port of Barcelona. This modern method, standardized worldwide, is a step forward […]

Recent advances of rapid load testing in Asia and Europe

Autor(s): Chew, S.H.; Middendorp, P.; Bakker J.; Chua G. Year: 2015 Language: English Where: Procedings XVI European Conference on Soil Mechanics and Geotechnical Engineering, Edinburgh, Scotland INTRODUCTION: Rapid Load Testing (RLT), by which a quasi-static load is applied to a foundation pile, is used increas- ingly as an alternative to static load testing (SLT) and […]

StatRapid, a new development for rapid load testing

StatRapid, eine Neuentwicklung für Rapid-Load-Testing Autor(s): P. Middendorp, L. de Neef, R. van Dorp, A. Lambo Year: 2013 Language: German Where: Pfahlsymposium Braunschweig Einführung: In der Vergangenheit reifte die Erkenntnis, dass die Ermittlung der Widerstände von Pfählen mit dynamischen Probebelastungen (DLT) in Kombination mit Signalanpassungstechniken wie CAPWAP, TNOWAVE und AllWave-DLT eine breite Streuung der Ergebnisse […]

How a dieselhammer works – Voitus van Hamme

Autor(s): Voitus van Hamme Year: 1981 Language: Dutch Where: Technical University Delft, The Netherlands INTRODUCTION: This Dutch thesis with English summary describes the operation of the diesel hammer and the theory of pile driving. Field measurements are also shown and analyzed. The process of the diesel block is divided into 8 phases: 1. fall and […]

From very small to gigantic piles

Autor(s): Middendorp P.; van Dorp R.F. Year: 2012 Language: Dutch Where: Geotechniek Funderingsdag 2012 special INTRODUCTION: The theme Foundations in Motion has been the practice for Allnamics in the short period of its existence since 2010, both literally and figuratively, for several national and international projects in the field of Mini- to Giga-piles. It is […]

Renovation of pile foundations for homes in Zaanstad

Om en om renovatie van paalwoningen voor woningen in Zaanstad Autor(s): Ad Offenberg Year: 1981 Language: Dutch Where: Polytechnisch tijdschrift, editie bouwkunde, wegen en waterbouw INTRODUCTION: In this (dutch) article a description is given of the way how a wooden pile foundation was completed with concrete piles at a renovation in Zaandam the Netherlands. Because […]

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