Texas cone penetrometer foundation design method: Qualitative and quantitative assessment

This paper presents a qualitative and quantitative evaluation of the predictive validity of the Texas Cone Penetration (TCP) foundation design method. Allowable loads were determined using both strength-based and serviceability-based models and were further compared to predicted allowable loads using the TCP foundation design charts. The predictive validity of the TCP method was evaluated using a final dataset consisting of 60 full-scale load tests comprising 33 driven piles and 27 drilled shafts, all founded in soil materials. The qualitative evaluation consisted of a visual assessment of the scatterplot compared to the equal prediction line. In the case of the quantitative assessment, regression models were fitted to the dataset, and the accuracy and precision of the models were evaluated based on statistical analyses. Results show that the predictive validity of the TCP-based foundation design method is accurate with low precision. The qualitative evaluation of the strength-based data showed slight data scatter around the equal prediction line. In the case of the serviceability-based model, data points indicated the same slight scatter with major concentration above the equal prediction line in the conservative prediction region. With a p-value <.05, results from the quantitative analyses showed a statistically significant relationship between the proposed models and the allowable loads predicted using the TCP. The R-square value for the models was between 0.776 and 0.814.

[1]  John Turner.  Rock-Socketed Shafts for Highway Structure Foundations , 2006 .

[2]  Rozbeh B. Moghaddam,et al.  Evaluation of the TxDOT Texas cone penetration test and foundation design method including correction factors, allowable total capacity, and resistance factors at serviceability limit state , 2016 .

[3]  John J. Bowders,et al.  Engineering Policy Guidelines For Design Of Drilled Shafts , 2011 .

[4]  Rodrigo Salgado,et al.  Resistance Factors for Use in Load and Resistance Factor Design of Driven Pipe Piles in Sands , 2009 .

[5]  Yong-Seok Park,et al.  Prediction of End Bearing Capacity for Pre-Bored Steel Pipe Piles Using Instrumented Spt Rods , 2013 .

[6]  Priyantha W. Jayawickrama,et al.  Side-by-Side Correlation of Texas Cone Penetration and Standard Penetration Test Blowcount Values , 2018, Geotechnical and Geological Engineering.

[7]  L K Moulton,et al.  Tolerable movement criteria for highway bridges , 1981 .

[8]  James G. Surles,et al.  Implementation of LRFD geotechnical design for deep foundations using Texas Cone Penetrometer (TCP) test. , 2015 .

[9]  Garland Likins,et al.  Geotechnical Engineering Circular No. 12 – Volume IIDesign and Construction of Driven Pile Foundations , 2016 .

[10]  L C Reese,et al.  DRILLED SHAFTS: CONSTRUCTION PROCEDURES AND DESIGN METHODS , 1999 .

[11]  Anil Misra,et al.  Performance-Based Design of Deep Foundation Systems in Load and Resistance Factor Design Framework , 2010 .

[12]  Farrel Zwerneman,et al.  Insights into Using the 22nd Edition of API RP 2A Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms - Working Stress Design , 2012 .

[13]  M. Davisson.  High capacity piles , 1972 .

[14]  L K Moulton,et al.  TOLERABLE MOVEMENT CRITERIA FOR HIGHWAY BRIDGES. FINAL REPORT , 1985 .