Standard penetration test energy measurements using a system based on the personal computer

1992 ◽  
Vol 29 (4) ◽  
pp. 551-557 ◽  
Author(s):  
Peter K. Robertson ◽  
David J. Woeller ◽  
Kofi O. Addo
Keyword(s):  
Energy Transfer ◽  
Test Procedure ◽  
Standard Penetration Test ◽  
Energy Calibration ◽  
Calibration System ◽  
Penetration Test ◽  
Reference Test ◽  
Time Record ◽  
Force Time

According to the International Reference Test procedure for the standard penetration test (SPT), in situations where comparisons of SPT results are important, calibrations should be made to evaluate the efficiency of the equipment in terms of energy transfer. However, equipment to measure the energy transfer of the hammer anvil system is not commonly available. Ten years ago a system was developed and made commercially available. However, this system is no longer available. An SPT energy calibration system is described that has been developed based on a microcomputer. The load cell to measure the compressive stress wave beneath the SPT anvil consists of a 0.5-m length of strain-gauged AW rod. Specialized software has been developed to record the force–time record for each hammer blow on a portable microcomputer. Examples of energy measurements are presented and discussed. Key words : standard penetration test, in situ, microcomputer, energy.

Standard penetration test (SPT): International reference test procedure

1990 ◽  
Vol 27 (2) ◽  
pp. A93
Author(s):  
L. Decourt ◽  
T. Muromachi ◽  
I.K. Nixon ◽  
J.H. Schmertmann ◽  
S. Thorburn ◽  
...  
Keyword(s):  
Test Procedure ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Reference Test ◽  
International Reference

Assessment of the range of variation of Nγ from 60 estimation methods for footings on sand

2013 ◽  
Vol 50 (7) ◽  
pp. 793-800 ◽  
Author(s):  
Edgar Giovanny Diaz-Segura
Keyword(s):  
Friction Angle ◽  
Standard Penetration Test ◽  
Estimation Methods ◽  
Penetration Test ◽  
In Situ Tests ◽  
Vertical Loading ◽  
Simplified Method ◽  
Bearing Capacity Factor ◽  
Range Of Variation

The range of variation of the bearing capacity factor, Nγ, was assessed using 60 estimation methods for rough footings on sand subjected to static vertical loading. The influence on the Nγ values of the use of correlations for the estimation of the friction angle, [Formula: see text], derived from in situ tests was also assessed. The analysis shows a marked dependency on the methods used to determine Nγ, showing differences for the same [Formula: see text] values of up to 267% between estimated values. Uncertainty in the estimation of [Formula: see text], due to the use of correlations with in situ tests, leads to a range of variation for Nγ higher than that seen using the 60 estimation methods. Finally, given the regular use of the in situ standard penetration test (SPT) on sands, and based on a series of analyses using finite elements, a simplified method in terms of the SPT N-values is proposed for estimation of Nγ in footings on sands.

scholarly journals PROPOSTA DE APLICAÇÃO DE RESULTADOS DE SONDAGENS COM MARTELO LEVE (DPL) NO CAMPO EXPERIMENTAL DA UNIFOR EM PROJETOS DE FUNDAÇÕES PARA PEQUENAS CARGAS [ Proposal for the Application of Dynamic Probing Light (DPL) Results in the Experimental Field of UNIFOR in Foundations Projects for Small Loads ]

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Marcos Fábio Porto de Aguiar ◽  
Fernando Feitosa Monteiro ◽  
Francisco Heber Lacerda de Oliveira ◽  
Yago Machado Pereira de Matos
Keyword(s):  
Bearing Capacity ◽  
Standard Penetration Test ◽  
Coefficient Of Determination ◽  
Deep Foundations ◽  
Penetration Test ◽  
In Situ Tests ◽  
Foundation Design ◽  
Experimental Field

RESUMO: Em meio aos diversos métodos utilizados no Brasil para determinação da capacidade de carga de fundações, a grande maioria parte do índice de resistência à penetração (NSPT). Para o caso de pequenas edificações, devido a fatores geralmente econômicos, a experiência ou a prática regional costumam prevalecer. Sendo assim, são elaborados, muitas vezes, projetos sem um procedimento de cálculo fundamentado em parâmetros comprovados por ensaios geotécnicos, podendo ocasionar problemas na edificação, como recalques excessivos, ou, até mesmo, comprometer a segurança da estrutura. Dessa forma, técnicas mais simples e de baixo custo, como o DPL (Dynamic Probing Light), podem ser uma opção para situações de pequenas cargas, viabilizando projetos fundamentados em ensaios in situ. Partindo de investigações com o DPL, este trabalho tem o objetivo de dimensionar fundações superficiais e profundas para edificações de pequeno porte através de algumas das principais metodologias disponíveis na literatura e verificar a sua eficiência. Por meio de resultados de campanhas de sondagens SPT (Standard Penetration Test) e DPL no campo experimental da Universidade de Fortaleza (UNIFOR), determinou-se a capacidade de carga de fundações superficiais e profundas fazendo aplicação dos índices NSPT e NSPT equivalente obtido pela correlação com o DPL. Identificou-se que essa correlação apresentou coeficiente de determinação satisfatório entre os parâmetros obtidos nos ensaios SPT e DPL para o terreno em questão, mostrando-se o DPL ser uma alternativa pertinente, em termos técnicos para projetos de fundações de obras de pequeno porte.ABSTRACT: Among the various methods used in Brazil of the determination of the bearing capacity on foundations, most part uses the standard penetration resistance (NSPT). For small constructions, due to economic factors generally, experience or regional practice usually prevails. Thus, projects without a reasoned calculation procedure in parameters supported by geotechnical tests are often designed, and may cause problems in the building, as excessive settlements, or even compromise the safety of the structure. In this way, simple and low cost techniques such as DPL (Dynamic Probing Light) may be an option for small loads situations, enabling projects based on in situ tests. This paper proposes to calculate the dimensions of shallow and deep foundations for small constructions and check its efficiency using DPL tests. Through the results of SPT (Standard Penetration Test) and DPL tests in the experimental field of the University of Fortaleza (UNIFOR), the determination of the bearing capacity in shallow and deep foundations was done using NSPT index and equivalent NSPT index obtained by the correlation with DPL. A correlation with satisfactory coefficient of determination was obtained between SPT and DPL tests parameters for the analyzed field, showing up the DPL as an appropriate alternative in technical terms for foundation design of small constructions.

Becker and standard penetration tests (BPT–SPT) correlations with consideration of casing friction

1994 ◽  
Vol 31 (3) ◽  
pp. 343-356 ◽  
Author(s):  
Alex Sy ◽  
R.G. (Dick) Campanella
Keyword(s):  
British Columbia ◽  
Energy Transfer ◽  
Stress Wave ◽  
Standard Penetration Test ◽  
Energy Output ◽  
Rational Approach ◽  
Stress Wave Propagation ◽  
Penetration Test ◽  
In Situ Tests ◽  
Foundation Design

The Becker penetration test (BPT), through correlations with the standard penetration test (SPT), is widely used for foundation design and liquefaction assessment in gravelly soils. Most of the existing correlations, however, do not adequately account for the variable energy output of the diesel hammer used in the Becker system, and shaft friction on the Becker casing is ignored. An alternative and more rational approach to BPT–SPT correlations is presented, based on experimental and numerical studies conducted at the University of British Columbia. The research involves performing SPT, BPT, and other in situ tests at several sites in British Columbia and includes dynamic measurements of energy transfer in the SPT and BPT. Stress-wave measurements and wave-equation analyses are used to evaluate the effect of friction on the BPT blow count. New BPT–SPT correlations are proposed that consider the energy transfer in both tests and explicitly consider casing friction in the BPT. A recommended procedure for estimating equivalent SPT N60 from BPT blow count is presented. Key words : Becker penetration test, standard penetration test, dynamic measurement, pile driving, stress-wave propagation.

scholarly journals ANÁLISE DE PERFIS DE SONDAGEM SPT E CARACTERIZAÇÃO GEOTÉCNICA DE SOLOS DO MUNICÍPIO DE NATAL

2007 ◽  
Vol 1 ◽  
pp. 38
Author(s):  
Kadson Ranniere da Rocha Câmara ◽  
Alexandre da Costa Pereira
Keyword(s):  
Standard Penetration Test ◽  
Penetration Test

O presente trabalho tem como objetivo a caracterização geotécnica de solos do município de Natal para fins de obtenção de parâmetros de resistência ao cisalhamento e de deformabilidade do material. Quatro zonas foram definidas para a compilação de resultados de relatórios de sondagens tipo SPT (Standard Penetration Test), buscando-se destacar aspectos que diferenciem geotecnicamente as zonas consideradas. Campanhas de ensaios de laboratório foram relizadas para a idendificação de características geotécnicas (perfil de umidades e granulometria, densidade das partículas e deformabilidade) de solo definido como referência para as análises. Parâmetros de resistência ao cisalhamento e de deformabilidade dos solos encontrados foram determinados mediante emprego de equações empíricas. Os resultados encontrados indicam haver importante variabilidade nas propriedades geotécnicas dos solos analisados, tanto para solos pertencentes a uma mesma zona como para solos de zonas distintas. O posicionamento das unidades geotécnicas e o estado de compacidade das mesmas consistem em variáveis destacadas no estudo realizado. Palavras-chaves: Mecânica dos Solos; Ensaios In Situ; Perfis SPT; Caracterização Geotécnica.

scholarly journals Effect of Hammer Shape on Energy Transfer Measurement in the Standard Penetration Test

2004 ◽  
Vol 44 (3) ◽  
pp. 103-114 ◽  
Author(s):  
Jiin-Song Tsai ◽  
Yean-Jhe Liou ◽  
Fu-Chen Liu ◽  
Chin-Huei Chen
Keyword(s):  
Energy Transfer ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Transfer Measurement

Evaluation of overburden stress effects on liquefaction resistance at Duncan Dam

2012 ◽  
Vol 49 (9) ◽  
pp. 1052-1058 ◽  
Author(s):  
Ross W. Boulanger ◽  
I.M. Idriss
Keyword(s):  
Standard Penetration Test ◽  
Triaxial Testing ◽  
Penetration Test ◽  
Liquefaction Resistance ◽  
Stress Effects ◽  
Cyclic Resistance ◽  
Evaluation Procedures ◽  
Direct Simple Shear ◽  
Overburden Stress

The cyclic resistance of sand unit 3c at Duncan Dam in British Columbia for overburden stresses of about 2 to 12 atm (1 atm = 101.325 kPa) was evaluated previously using cyclic undrained direct simple shear (DSS) and cyclic undrained triaxial testing of samples obtained using frozen sampling techniques. The in situ standard penetration test (SPT) and laboratory testing results provide a unique set of data for evaluating how the effects of effective overburden stress are accounted for in liquefaction evaluation procedures. The present study re-examines the cyclic resistance of these sands based on the field and laboratory test data for the unit 3c sands underlying Duncan Dam relative to the site-specific procedures developed by Pillai and Byrne and the liquefaction triggering evaluation procedures presented by Idriss and Boulanger, Youd et al., and Cetin et al. The differences in the results and the reasons for the differences are discussed.

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