CAPWAP and Refined Wave Equation Analyses for Driveability Predictions and Capacity Assessment of Offshore Pile Installations

2009 ◽  
Author(s):  
Frank Rausche ◽  
Matt Nagy ◽  
Scott Webster ◽  
Liqun Liang
Keyword(s):  
Wave Equation ◽  
Bearing Capacity ◽  
Dynamic Monitoring ◽  
Capacity Assessment ◽  
Pile Driving ◽  
Soil Resistance ◽  
Driving Dynamic ◽  
Deep Foundation ◽  
Driving System ◽  
Equation Analysis

Open ended pipe piles have to be driven in the offshore environment primarily as platform support piles or as conductor pipes. In either case, deep penetrations have to be achieved. In preparation of these potentially difficult installations, equipment selection and stress control is done by a predictive wave equation analysis. During pile driving, dynamic monitoring combined with CAPWAP signal matching analysis is a preferred method for bearing capacity assessment. After the fact, if dynamic measurements were not provided during pile driving, a wave equation analysis can again help perform a post-installation analysis for bearing capacity assessment, assuming a variety of parameters. Wave equation analyses require a variety of input parameters describing hammer and driving system performance and the pseudo-static and dynamic behavior of the soil. Measurements taken during the installation yield immediate results about hammer and pile performance. Soil resistance parameters can be extracted by careful signal matching analysis. Unfortunately, the measurement and associated analysis results cannot be used without further modification in the wave equation analysis, because the wave equation approach requires simplifications in hammer, driving system and soil models. Thus, a final step is the so-call Refined Wave Equation Analysis which combines all results obtained and produces a best possible match between measurements and analyses. This paper describes the process of the three analysis phases utilizing typical offshore pile installation records. The paper also gives guide lines for this analysis process as well as a summary of limitations. An important part of the paper includes recommendations for and discussion of the modeling of the soil resistance near the open ended pipe bottom. Finally, the paper discusses how the results should be used for greatest benefit of the deep foundation industry.

Comparative Study on Prediction of Axial Bearing Capacity of Driven Piles in Granular Materials

2013 ◽  
Vol 61 (3) ◽  
Author(s):  
Ehsan Momeni ◽  
Harnedi Maizir ◽  
Nurly Gofar ◽  
Ramli Nazir
Keyword(s):  
Finite Element ◽  
Wave Equation ◽  
Bearing Capacity ◽  
Load Test ◽  
Dynamic Monitoring ◽  
Static Load Test ◽  
Element Analysis ◽  
Axial Capacity ◽  
Equation Analysis ◽  
Semi Empirical

Estimation of axial bearing capacity plays an essential role in pile design. A part from semi-empirical and numerical methods, axial bearing capacity of piles can be either predicted by means of a maintain load test or dynamic load test. The latter test is based on wave equation analysis and it is provided by Pile driving analyzer (PDA). Combination of wave equation analysis with dynamic monitoring of the pile can result in prediction of axial bearing capacity of the pile and its distribution. This paper compares the axial capacity of pile obtained from PDA records and  maintain load test (static load test) with predicted axial capacities obtained using analytical, empirical and finite element analysis. From the results it is observed that axial bearing capacity derived from numerical modelling with the aid of the finite element code, Plaxis, is in a good agreement with estimated axial capacity through analytical-empirical methods, PDA, and maintain load test.

Prediction of Static Bearing Capacity from Wave Equation Analysis

1970 ◽  
Author(s):  
Harry M. Coyle ◽  
Richard E. Bartoskewitz ◽  
Lee L. Lowery
Keyword(s):  
Wave Equation ◽  
Bearing Capacity ◽  
Equation Analysis

Analytical model for an innovative pile test

1992 ◽  
Vol 29 (4) ◽  
pp. 569-579 ◽  
Author(s):  
M. H. El Naggar ◽  
M. Novak
Keyword(s):  
Mathematical Model ◽  
Bearing Capacity ◽  
Model Parameters ◽  
Pile Driving ◽  
Driving Dynamic ◽  
Pile Capacity ◽  
Pile Test ◽  
Response Dynamic ◽  
Proposed Model ◽  
New Type

In recent years a new type of pile test employing a short-duration load was developed that became known as pile statnamic test. The paper describes a method of dynamic analysis specifically formulated for this test. The aim of the analysis is twofold: to calculate the pile load displacements in such a way that a satisfactory match with the data measured during the test is obtained; and using the model parameters established from this comparison to predict the bearing capacity of the pile. The mathematical model is one-dimensional and accounts for slip as well as energy dissipation in the far field. Unlike the empirical parameters of the Smith model for pile driving analysis, the parameters of the proposed model are, for the most part, directly related to standard geotechnical parameters. The case studies conducted thus far and described in the paper indicate that the proposed mathematical model works very well and that the statnamic test may become a useful tool for pile capacity prediction. Key words : piles, pile driving, dynamic response, dynamic tests, bearing capacity.

Wave Equation Analysis Of Instrumented Test Pile

1973 ◽  
Author(s):  
Harry M. Coyle ◽  
Robert Foye ◽  
Richard E. Bartoskewitz
Keyword(s):  
Wave Equation ◽  
Equation Analysis ◽  
Test Pile

Discussion of “Pile-Driving Analysis by the Wave Equation”

1962 ◽  
Vol 127 (1) ◽  
pp. 1171-1189
Author(s):  
L. O. Soderberg ◽  
Marvin Gates ◽  
E. Jonas ◽  
A. A. Eremin ◽  
G. M. Cornfield ◽  
...  
Keyword(s):  
Wave Equation ◽  
Pile Driving

Improving the Predictability of Hiley Pile Driving Formula in the Quality Control of the Pile Foundation

2011 ◽  
Vol 261-263 ◽  
pp. 1292-1296
Author(s):  
Hamayon Tokhi ◽  
Gang Ren ◽  
Yi Min Xie
Keyword(s):  
New Technologies ◽  
Dynamic Testing ◽  
Poor Performance ◽  
Pile Driving ◽  
Testing Methods ◽  
Pile Capacity ◽  
Equation Analysis ◽  
Pros And Cons ◽  
Recent Method ◽  
Major Factors

Pile Dynamic Formulas are the oldest and frequently used method to determine bearing capacity of piles. The more recent method is based on the Wave Equation analysis and different formulations such as Case Mathod, TNO, CAPWAP and TEPWAP which were developed for pre-driving analysis and post-driving measurements applications. The major factors for the common use of the dynamic formulas have been due to their simplicity, cost effectiveness and applicability in various piling situations. However, in some literature the energy approach have been given an unfair reputation as being unreliable and less accurate than the more analytical or dynamic testing methods. One of the issues due to the poor performance of the dynamic formulas is that, historically, the hammer energy and the energy trasferred to pile had to be assumed. Nevertheless, with the advent of computers, new technologies are emerging with the advancement in construction industry. This has produced gradual improvements that have resulted in the dynamic method to be used on many projects with greater reliability. In this paper, a review of the different testing methods as well as pros and cons of the pile driving formulas are discussed. Also, an approach to improving the widely used Hiley dynamic equation is presented. This approach enables evaluation of the pile capacity to be made more accurately.

scholarly journals Effect of Pile Spacing on Group Efficiency in Gypseous Soil

2019 ◽  
Vol 5 (2) ◽  
pp. 373 ◽  
Author(s):  
Bilal Jabbar Noman ◽  
Safaa H. Abd-Awn ◽  
Hassan O. Abbas
Keyword(s):  
Bearing Capacity ◽  
Load Condition ◽  
Soil Mass ◽  
Deep Foundation ◽  
Collapsible Soil ◽  
Floating Pile ◽  
Group Efficiency ◽  
Gypsum Content ◽  
Group Pile ◽  
Gypseous Soil

As a matter of fact, the gypseous soil is usually considered as collapsible soil, such type of soil illustrates high resistance to settlement and high bearing capacity when it is dry, but it loses these characteristics when it is inundated and collapses excessively because of the sudden decrease in the volume of the surrounding soil mass. It is founded in the arid and semi-arid regions of the world in Asia, South Asia (Iraq, Syria, Jordan, Yemen, and Iran), North Africa, North America, moreover, it covers more than (31%) of the surface area in Iraq. Gypseous soil is one of the most difficult problems facing the process of building any project because of the difficulty of preventing leakage of water to the soil in practice. Deep foundation (piles) are one of the most common types used in collapsible soils which penetrating problematic soil layers and reaching more hard ones (end bearing piles) or transfers loads depending on skin friction (floating pile). The current work is directed to study the behavior of single and group driven pile of square pattern (4 piles) in case of floating pile (friction pile) with different spacing (2D, 4D, 6D) and length to diameter (L/D) ratio of (20) in this special medium dense soil (gypsum content 30% and 61%) under axial load condition. The investigation was carried out to measure the soil collapse before and after inundation. The results showed that the group efficiency for spacing 2D is less than one while for spacing 4D and 6D are more than that value. In addition, the spacing 4D was more efficient to carry 4 group pile in both dry and soaked cases, in addition, the result showed a high reduction in the bearing capacity at inundation state of group pile of (82% in gypsum content 30%) and ( 87% in gypsum content 61%) with respect to dry state.

scholarly journals A model for ultimate bearing capacity of piles in unsaturated soils under elevated temperatures

2020 ◽  
Vol 205 ◽  
pp. 05003
Author(s):  
Sannith Kumar Thota ◽  
Farshid Vahedifard
Keyword(s):  
Bearing Capacity ◽  
Unsaturated Soils ◽  
Elevated Temperatures ◽  
Skin Resistance ◽  
Ultimate Bearing Capacity ◽  
Temperature Dependent ◽  
Deep Foundation ◽  
Energy Applications ◽  
Temperature Dependent Model ◽  
Pile Resistance

Geo-energy applications such as energy piles can expose unsaturated, deep foundation soils to elevated temperatures. This paper presents a closed-form equation for the ultimate bearing capacity of piles in unsaturated soils subject to elevated temperatures under drained conditions. For this purpose, a temperature-dependent effective stress model was incorporated into calculations of skin resistance and end bearing resistance of piles. The proposed temperature-dependent model is an extension of the modified β method for determining the ultimate pile bearing capacity of unsaturated soils under drained conditions. Employing the proposed model, a parametric study was carried out to evaluate the ultimate pile bearing capacity for hypothetical clay and silt soils at temperatures ranging from 25 °C to 55 °C. For both clay and silt, the results indicated that the ultimate pile bearing capacity varies with an increase in temperature. Different trends with temperature were observed for clay and silt. A monotonic increase in pile resistance was observed in clays. For silt, the pile resistance increased at relatively low matric suction whereas it decreased at higher matric suctions.

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