New ultimate pile capacity prediction method based on cone penetration test (CPT)

2012 ◽  
Vol 49 (8) ◽  
pp. 961-967 ◽  
Author(s):  
Zhihong Hu ◽  
Michael McVay ◽  
David Bloomquist ◽  
David Horhota ◽  
Peter Lai
Keyword(s):  
Design Method ◽  
Prediction Method ◽  
Cone Penetration Test ◽  
Resistance Factor ◽  
Penetration Test ◽  
Cone Penetration ◽  
Pile Capacity ◽  
Promising Alternative ◽  
Resistance Factors ◽  
Pile Design

Our research evaluated current cone penetration test (CPT) pile design methodologies (Schmertmann, Laboratoire Central des Ponts et Chaussées (LCPC), etc.), modified one of these methods (Philipponnat method), and proposed a new one to improve future driven pile designs. This was accomplished by evaluating 14 pile-capacity-design methods based on CPT data. Furthermore, load and resistance factor design (LRFD) resistance factors for each method were calculated using 21 cases from Florida and 28 from Louisiana. The resulting resistance factors were not satisfactory for any of these methods. A new design method — the University of Florida (UF) method — was proposed taking into account cementation, soil type, and historical data. The LRFD resistance factor was also assessed for this new method. The proposed UF method provides better LRFD resistance factors for both Florida and Louisiana soils. It could be a promising alternative for improving pile design.

Full-scale pile tests in sand and development of a computer program for predicting load capacity

2007 ◽  
Vol 34 (10) ◽  
pp. 1222-1236 ◽  
Author(s):  
J K.C Shih ◽  
J R Omer ◽  
R Delpak ◽  
R B Robinson ◽  
C D Jones
Keyword(s):  
Computer Program ◽  
Scale Effects ◽  
Soil Mechanics ◽  
Load Capacity ◽  
Pressure Coefficient ◽  
Prediction Method ◽  
Cone Penetration Test ◽  
Load Test ◽  
Penetration Test ◽  
Cone Penetration

An interactive computer program GLAMPILE has been developed for predicting the static load capacity of single piles formed in any soil profile. A variety of well-known prediction methods have been incorporated into the program, including (i) soil mechanics based formulae; (ii) direct and indirect cone penetration test (CPT) based methods with and without accounting for scale effects of the cone on pile base capacity; and (iii) a new CPT-based method that considers the effects of “critical depth” and shaft resistance distribution, although the method has only been calibrated for relatively short piles. GLAMPILE can cope with different pile types installed with or without a permanent casing. The program has been applied to predict the axial capacities of 11 piles that were recently installed in sand and statically loaded to failure. Results from the soil mechanics procedures indicate increases, on the in situ value, of the earth pressure coefficient by up to 37%, which lies within the range 0%–100% recommended in the literature. The best CPT-based prediction method applied yields a mean (µ) and coefficient of variation (COV) of predicted to measured pile head capacity (Puh(p)/Puh(m)) of 0.83 and 0.12, respectively. Scale effects are shown to be nominal for the cases analysed. An improved method is recommended, which yields µ = 1.00 and COV = 0.10, implying higher accuracy and reliability compared with the other methods.Key words: piles, cone penetration test, static and dynamic load test, modular program.

Seismic cone penetration test and seismic tomography in permafrost

2004 ◽  
Vol 41 (5) ◽  
pp. 796-813 ◽  
Author(s):  
Anne-Marie LeBlanc ◽  
Richard Fortier ◽  
Michel Allard ◽  
Calin Cosma ◽  
Sylvie Buteau
Keyword(s):  
Seismic Tomography ◽  
Dynamic Properties ◽  
Cone Penetration Test ◽  
The Body ◽  
Body Waves ◽  
Reconstruction Technique ◽  
Seismic Velocities ◽  
Penetration Test ◽  
Cone Penetration ◽  
Seismic Cone Penetration Test

Two high-resolution multi-offset vertical seismic profile (VSP) surveys were carried out in a permafrost mound near Umiujaq in northern Quebec, Canada, while performing seismic cone penetration tests (SCPT) to study the cryostratigraphy and assess the body waves velocities and the dynamic properties of warm permafrost. Penetrometer-mounted triaxial accelerometers were used as the VSP receivers, and a swept impact seismic technique (SIST) source generating both compressional and shear waves was moved near the surface following a cross configuration of 40 seismic shot-point locations surrounding each of the two SCPTs. The inversion of travel times based on a simultaneous iterative reconstruction technique (SIRT) provided tomographic images of the distribution of seismic velocities in permafrost. The Young's and shear moduli at low strains were then calculated from the seismic velocities and the permafrost density measured on core samples. The combination of multi-offset VSP survey, SCPT, SIST, and SIRT for tomographic imaging led to new insights in the dynamic properties of permafrost at temperatures close to 0 °C. The P- and S-wave velocities in permafrost vary from 2400 to 3200 m/s and from 900 to 1750 m/s, respectively, for a temperature range between –0.2 and –2.0 °C. The Young's modulus varies from 2.15 to 13.65 GPa, and the shear modulus varies from 1.00 to 4.75 GPa over the same range of temperature.Key words: permafrost, seismic cone penetration test, vertical seismic profiling, seismic tomography, dynamic properties.

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