Pub Date : 2014-10-01DOI: 10.1179/1937525514Y.0000000010
L. Laloui, C. Olgun, M. Sutman, J. McCartney, C. Coccia, H. Abuel-Naga, G. A. Bowers
Abstract This paper focuses on the main issues discussed during a session on the impact of thermohydromechanical behavior of soils on thermoactive geotechnical systems, and how they could affect the performance of thermoactive geotechnical systems. Both soil behavior as well as soil–structure interaction behavior was discussed. The main observation from the session was that the thermohydromechanical behavior of saturated soils has reached a mature understanding, with several established constitutive models that can be used by engineers. However, there are still opportunities to enhance these constitutive models by considering issues such as unsaturated conditions, anisotropic stress states, cyclic heating and cooling effects, and changes in the preconsolidation stress during heating and cooling. Further there are still opportunities to improve our understanding of soil/concrete interface behavior, including the development of novel testing approaches.
{"title":"Issues involved with thermoactive geotechnical systems: characterization of thermomechanical soil behavior and soil-structure interface behavior","authors":"L. Laloui, C. Olgun, M. Sutman, J. McCartney, C. Coccia, H. Abuel-Naga, G. A. Bowers","doi":"10.1179/1937525514Y.0000000010","DOIUrl":"https://doi.org/10.1179/1937525514Y.0000000010","url":null,"abstract":"Abstract This paper focuses on the main issues discussed during a session on the impact of thermohydromechanical behavior of soils on thermoactive geotechnical systems, and how they could affect the performance of thermoactive geotechnical systems. Both soil behavior as well as soil–structure interaction behavior was discussed. The main observation from the session was that the thermohydromechanical behavior of saturated soils has reached a mature understanding, with several established constitutive models that can be used by engineers. However, there are still opportunities to enhance these constitutive models by considering issues such as unsaturated conditions, anisotropic stress states, cyclic heating and cooling effects, and changes in the preconsolidation stress during heating and cooling. Further there are still opportunities to improve our understanding of soil/concrete interface behavior, including the development of novel testing approaches.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125843015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-01DOI: 10.1179/1937525514Y.0000000011
C. Olgun, John S. McCartney, F. Loveridge, G. A. Bowers, C. Coccia, A. Bouazza, Kenichi Soga, J. Spitler, Duncan Nicholson, M. Sutman
Abstract The purpose of this paper is to provide a current state of affairs regarding the existing building codes in relation to thermoactive foundations, if any exist at all. This paper also explores regional incentives in the form of energy and carbon requirements for new structures as a potential driver for thermoactive foundation implementation. Two Green Certification programs, LEED and BREEAM, are discussed which both offer credit for shallow geothermal energy systems. The actual implementation of thermoactive foundation technology has proved to be challenging due to the complications arising out of the concept development stage and the coordination required among the various parties involved in the design stage. A discussion of these challenges and an outline of the deliverables needed of those in academia and industry in order to progress is included.
{"title":"Building codes, green certification and implementation issues, market challenges","authors":"C. Olgun, John S. McCartney, F. Loveridge, G. A. Bowers, C. Coccia, A. Bouazza, Kenichi Soga, J. Spitler, Duncan Nicholson, M. Sutman","doi":"10.1179/1937525514Y.0000000011","DOIUrl":"https://doi.org/10.1179/1937525514Y.0000000011","url":null,"abstract":"Abstract The purpose of this paper is to provide a current state of affairs regarding the existing building codes in relation to thermoactive foundations, if any exist at all. This paper also explores regional incentives in the form of energy and carbon requirements for new structures as a potential driver for thermoactive foundation implementation. Two Green Certification programs, LEED and BREEAM, are discussed which both offer credit for shallow geothermal energy systems. The actual implementation of thermoactive foundation technology has proved to be challenging due to the complications arising out of the concept development stage and the coordination required among the various parties involved in the design stage. A discussion of these challenges and an outline of the deliverables needed of those in academia and industry in order to progress is included.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130548468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-01DOI: 10.1179/1937525514Y.0000000006
T. Amis, J. McCartney, F. Loveridge, C. Olgun, M. E. Bruce, K. D. Murphy
Abstract This paper summarizes recommendations for best practice associated with the installation of geothermal loops within foundations to form thermopiles, based on experience gained over the past 10 years in the UK. The issue of paramount importance in constructing a successful thermopile installation is the early stage coordination with all parties that will encounter, install or test the geothermal loops. Several lessons learned from the installation and construction of thermopiles are described to help ensure a smooth installation process. As long as there is early coordination, the installation of geothermal heat exchange tubing is relatively simple and will have very little or no impact on typical deep foundation installation procedures. This, coupled with the fact that there are additional costs and implications associated with other geothermal heat exchange approaches, implies that thermopiles are an ideal economic solution to access a renewable energy source.
{"title":"Identifying best practice, installation, laboratory testing and field testing","authors":"T. Amis, J. McCartney, F. Loveridge, C. Olgun, M. E. Bruce, K. D. Murphy","doi":"10.1179/1937525514Y.0000000006","DOIUrl":"https://doi.org/10.1179/1937525514Y.0000000006","url":null,"abstract":"Abstract This paper summarizes recommendations for best practice associated with the installation of geothermal loops within foundations to form thermopiles, based on experience gained over the past 10 years in the UK. The issue of paramount importance in constructing a successful thermopile installation is the early stage coordination with all parties that will encounter, install or test the geothermal loops. Several lessons learned from the installation and construction of thermopiles are described to help ensure a smooth installation process. As long as there is early coordination, the installation of geothermal heat exchange tubing is relatively simple and will have very little or no impact on typical deep foundation installation procedures. This, coupled with the fact that there are additional costs and implications associated with other geothermal heat exchange approaches, implies that thermopiles are an ideal economic solution to access a renewable energy source.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"431 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132529922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-01DOI: 10.1179/1937525514Y.0000000013
P. Bourne-Webb, Jean-Michel Pereira, G. A. Bowers, T. Mimouni, F. Loveridge, S. Burlon, C. Olgun, J. McCartney, M. Sutman
Abstract This paper presents a review of current design tools used for thermoactive geotechnical systems, along with validation efforts. The capabilities of available analytical methods used for the thermal and thermomechanical design of these systems are evaluated and shortcomings of the existing methods are identified. Although the analytical methods permit accurate prediction of the thermal stress and strain response of thermoactive piles from readily available soil and concrete properties, current shortcomings consist of the ability of the methods to simulate cyclic heating and cooling effects, transient pore water pressure generation and dissipation, and the effects of radial stress changes. Recommendations are provided on how to properly address the current design requirements and the efforts to overcome shortcomings with the development of constitutive relationships from further full scale and laboratory scale experimental studies on thermoactive piles. Furthermore, the need for the development of both simplified analytical tools and advanced finite element models is emphasized. In addition, the existing analytical tools should be validated using field data from recently available case studies of thermoactive piles in varying soil deposits. An urgent need for an extensive design guide for energy geostructures was identified. The guidelines should be targeted towards practitioners and include field observations and measurements, as well as laboratory and numerical studies.
{"title":"Design tools for thermoactive geotechnical systems","authors":"P. Bourne-Webb, Jean-Michel Pereira, G. A. Bowers, T. Mimouni, F. Loveridge, S. Burlon, C. Olgun, J. McCartney, M. Sutman","doi":"10.1179/1937525514Y.0000000013","DOIUrl":"https://doi.org/10.1179/1937525514Y.0000000013","url":null,"abstract":"Abstract This paper presents a review of current design tools used for thermoactive geotechnical systems, along with validation efforts. The capabilities of available analytical methods used for the thermal and thermomechanical design of these systems are evaluated and shortcomings of the existing methods are identified. Although the analytical methods permit accurate prediction of the thermal stress and strain response of thermoactive piles from readily available soil and concrete properties, current shortcomings consist of the ability of the methods to simulate cyclic heating and cooling effects, transient pore water pressure generation and dissipation, and the effects of radial stress changes. Recommendations are provided on how to properly address the current design requirements and the efforts to overcome shortcomings with the development of constitutive relationships from further full scale and laboratory scale experimental studies on thermoactive piles. Furthermore, the need for the development of both simplified analytical tools and advanced finite element models is emphasized. In addition, the existing analytical tools should be validated using field data from recently available case studies of thermoactive piles in varying soil deposits. An urgent need for an extensive design guide for energy geostructures was identified. The guidelines should be targeted towards practitioners and include field observations and measurements, as well as laboratory and numerical studies.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132216843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.1179/1937525514Y.0000000003
A. Stuedlein, S. C. Reddy, T. M. Evans
Abstract Instrumented static loading tests present an effective tool for appropriate engineering of piled foundations. Whether instrumented or not, considerable effort can be expended to determine the interpreted failure load developed during the loading test, and the determination of an appropriate capacity is often subject to regulatory review and discussion, which may be complicated by the large number of interpretation methods available and the large range in interpreted capacities that could result. This paper focuses on the differences in the interpreted failure load for augered cast in place (ACIP) piles and seeks to determine which methods are suitable and which methods are inappropriate for the interpretation of ACIP piles. First, a review of various capacity interpretation methods is provided with emphasis on those methods cited in the International Building Code (). Then, an ACIP pile case history database used to illustrate differences in interpreted capacity is described, followed by the presentation of the resulting differences. Recommendations for and against the use of several failure load interpretation methods are made. This paper emphasizes the importance of both the interpretation of the failure load as well as the consequence of a particular methodology on displacement – a critical performance measure.
{"title":"Interpretation of augered cast in place pile capacity using static loading tests","authors":"A. Stuedlein, S. C. Reddy, T. M. Evans","doi":"10.1179/1937525514Y.0000000003","DOIUrl":"https://doi.org/10.1179/1937525514Y.0000000003","url":null,"abstract":"Abstract Instrumented static loading tests present an effective tool for appropriate engineering of piled foundations. Whether instrumented or not, considerable effort can be expended to determine the interpreted failure load developed during the loading test, and the determination of an appropriate capacity is often subject to regulatory review and discussion, which may be complicated by the large number of interpretation methods available and the large range in interpreted capacities that could result. This paper focuses on the differences in the interpreted failure load for augered cast in place (ACIP) piles and seeks to determine which methods are suitable and which methods are inappropriate for the interpretation of ACIP piles. First, a review of various capacity interpretation methods is provided with emphasis on those methods cited in the International Building Code (). Then, an ACIP pile case history database used to illustrate differences in interpreted capacity is described, followed by the presentation of the resulting differences. Recommendations for and against the use of several failure load interpretation methods are made. This paper emphasizes the importance of both the interpretation of the failure load as well as the consequence of a particular methodology on displacement – a critical performance measure.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131041958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.1179/TBC14Z.0000000005
K. Ng
Abstract For bridges or buildings that may be subjected to large vertical and lateral loads, drilled shafts offer an economical foundation solution. While current drilled shaft design practices are considered adequate, a performance based approach to drilled shaft design can be more cost effective and produce a more dependable response. This study examined a performance-based design concept using load test data from 24 usable drilled shafts from several states. The process identified a challenge: the Osterberg (O-cell) load test method was unable to characterize the full top load–displacement response. When a typical single O-cell is utilized in a drilled shaft test, depending on the location of the O-cell and the geomaterials present along and beneath the shaft, the load test result typically quantifies either the side resistance or the end bearing reaching the maximum load–displacement curve but not both. This limitation hinders the determination of a suitable shaft resistance as a function of target top displacement. To overcome this challenge, a procedure is proposed for establishing the full load–displacement curve based on data gathered from one O-cell. The method is presented for three different cases (i.e. side resistance reaches the maximum value during the test, end bearing reaches the maximum value during the test and neither component reaches the maximum value). Because it allows characterization of the full load–displacement curve, the proposed procedure enables a performance based design of drilled shafts with due consideration to settlement while satisfying Load and Resistance Factor Design requirements.
{"title":"Towards performance based design of drilled shafts","authors":"K. Ng","doi":"10.1179/TBC14Z.0000000005","DOIUrl":"https://doi.org/10.1179/TBC14Z.0000000005","url":null,"abstract":"Abstract For bridges or buildings that may be subjected to large vertical and lateral loads, drilled shafts offer an economical foundation solution. While current drilled shaft design practices are considered adequate, a performance based approach to drilled shaft design can be more cost effective and produce a more dependable response. This study examined a performance-based design concept using load test data from 24 usable drilled shafts from several states. The process identified a challenge: the Osterberg (O-cell) load test method was unable to characterize the full top load–displacement response. When a typical single O-cell is utilized in a drilled shaft test, depending on the location of the O-cell and the geomaterials present along and beneath the shaft, the load test result typically quantifies either the side resistance or the end bearing reaching the maximum load–displacement curve but not both. This limitation hinders the determination of a suitable shaft resistance as a function of target top displacement. To overcome this challenge, a procedure is proposed for establishing the full load–displacement curve based on data gathered from one O-cell. The method is presented for three different cases (i.e. side resistance reaches the maximum value during the test, end bearing reaches the maximum value during the test and neither component reaches the maximum value). Because it allows characterization of the full load–displacement curve, the proposed procedure enables a performance based design of drilled shafts with due consideration to settlement while satisfying Load and Resistance Factor Design requirements.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129324074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.1179/1937525514Y.0000000002
R. Lautkankare, V. Sarola, H. Kanerva-Lehto
Abstract Energy piles are fairly new solutions and have gained significant traction around the globe. Since the twenty-first century, geothermal energy collector pipes are being frequently installed, finding its most common implementation in newly constructed buildings. Much less studied is the application of energy piles in existing buildings and older constructions. The biggest challenge in the utilization of energy micropiles in underpinning projects is related to the through holes for geothermal energy collector pipes in the load transfer structures. In the FIN-C2M project (Case 2 Micropile Research Project in ISM collaboration), several technical solutions were investigated to identify the most suitable options to accommodate the utilization of energy micropiles with minimum interference of the load transfer structures. At the moment there are 13 known load transfer structure cases and energy micropiles can be used with nine of them. In general, they cannot be used with jet grouting. In five of the studied cases, the through holes for the collector pipes can be constructed as found in new buildings. In the other four cases, where pretensioning is achieved by jacking directly above the micropile, the construction of through holes requires further development, for which limited suggestions exist, however; the challenge is to bypass the jack. This paper will present all nine cases along with construction details and recommendations for the utilization of energy micropiles in existing buildings.
{"title":"Energy piles in underpinning projects – through holes in load transfer structures","authors":"R. Lautkankare, V. Sarola, H. Kanerva-Lehto","doi":"10.1179/1937525514Y.0000000002","DOIUrl":"https://doi.org/10.1179/1937525514Y.0000000002","url":null,"abstract":"Abstract Energy piles are fairly new solutions and have gained significant traction around the globe. Since the twenty-first century, geothermal energy collector pipes are being frequently installed, finding its most common implementation in newly constructed buildings. Much less studied is the application of energy piles in existing buildings and older constructions. The biggest challenge in the utilization of energy micropiles in underpinning projects is related to the through holes for geothermal energy collector pipes in the load transfer structures. In the FIN-C2M project (Case 2 Micropile Research Project in ISM collaboration), several technical solutions were investigated to identify the most suitable options to accommodate the utilization of energy micropiles with minimum interference of the load transfer structures. At the moment there are 13 known load transfer structure cases and energy micropiles can be used with nine of them. In general, they cannot be used with jet grouting. In five of the studied cases, the through holes for the collector pipes can be constructed as found in new buildings. In the other four cases, where pretensioning is achieved by jacking directly above the micropile, the construction of through holes requires further development, for which limited suggestions exist, however; the challenge is to bypass the jack. This paper will present all nine cases along with construction details and recommendations for the utilization of energy micropiles in existing buildings.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124101011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.1179/TBC14Z.0000000001
M. Hajali, C. Abishdid
Abstract Cross-hole sonic logging (CSL) has over recent years become the standard method for evaluating the integrity of bridge drilled shafts. The CSL method is based on measuring the speed of ultrasonic waves traveling between probes in parallel tubes placed inside the drilled shaft. Several existing studies have proposed methods that rely on the arrival time and wave speed to evaluate concrete integrity of drilled shaft foundations such as cross-hole tomography. In this study, a processing method for a three-component wide band CSL data is presented. This method named frequency tomography analysis (FTA) is based on the change of the frequency amplitude of the signal recorded by the receiver probe at the location of anomalies. The signal’s time domain data are converted into frequency domain data using fast Fourier transform (FFT); the distribution of the FTA is then evaluated. This method is employed after a CSL test has determined a high probability of an anomaly in a given area and is applied to improve location accuracy and to further characterize the features of the anomaly. Two drilled shaft samples were built in Florida International University (FIU)’s Titan America Structures and Construction Testing (TASCT) Laboratory. Cubic foam pieces were placed inside the rebar cage before casting of concrete and throughout the length of the shaft. FTA was then utilized after the CSL tests to detect their location. The technique proved to have a very high resolution and was able to clarify the location of any artificial or planed discontinuities through the length of the drilled shaft.
{"title":"Cross-hole sonic logging and frequency tomography analysis of drilled shaft foundations to better evaluate anomalies locations","authors":"M. Hajali, C. Abishdid","doi":"10.1179/TBC14Z.0000000001","DOIUrl":"https://doi.org/10.1179/TBC14Z.0000000001","url":null,"abstract":"Abstract Cross-hole sonic logging (CSL) has over recent years become the standard method for evaluating the integrity of bridge drilled shafts. The CSL method is based on measuring the speed of ultrasonic waves traveling between probes in parallel tubes placed inside the drilled shaft. Several existing studies have proposed methods that rely on the arrival time and wave speed to evaluate concrete integrity of drilled shaft foundations such as cross-hole tomography. In this study, a processing method for a three-component wide band CSL data is presented. This method named frequency tomography analysis (FTA) is based on the change of the frequency amplitude of the signal recorded by the receiver probe at the location of anomalies. The signal’s time domain data are converted into frequency domain data using fast Fourier transform (FFT); the distribution of the FTA is then evaluated. This method is employed after a CSL test has determined a high probability of an anomaly in a given area and is applied to improve location accuracy and to further characterize the features of the anomaly. Two drilled shaft samples were built in Florida International University (FIU)’s Titan America Structures and Construction Testing (TASCT) Laboratory. Cubic foam pieces were placed inside the rebar cage before casting of concrete and throughout the length of the shaft. FTA was then utilized after the CSL tests to detect their location. The technique proved to have a very high resolution and was able to clarify the location of any artificial or planed discontinuities through the length of the drilled shaft.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114267141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.1179/1937525514Y.0000000001
M. El Gendy, I. A. El-Arabi, M. Kamal
Abstract This paper presents a series of comparisons of the load settlement behaviors of single large diameter bored piles, for two international codes (, 1990, and ) in addition to the Egyptian code (). The ultimate bearing capacities calculated by those codes for 38 pile case studies located in the Nile Delta and Port Said regions in Egypt are evaluated by the modified method. The main objective of this research is to compare the performance of the Egyptian code design methodology for large diameter bored piles, with the other international codes. Extensive comparisons are made between the calculations of the different codes regarding the total ultimate pile load as well as the individual contributions of the tip and skin resistances. Finally, an empirical simplified load settlement model deducted from code calculations of the ultimate load of large diameter bored piles is proposed. This model could simplify the analysis of piled raft as it can easily predict the pile settlement. The study assured that the pile load test is an irreplaceable process to estimate the ultimate pile capacity.
{"title":"Comparative analyses of large diameter bored piles using international codes","authors":"M. El Gendy, I. A. El-Arabi, M. Kamal","doi":"10.1179/1937525514Y.0000000001","DOIUrl":"https://doi.org/10.1179/1937525514Y.0000000001","url":null,"abstract":"Abstract This paper presents a series of comparisons of the load settlement behaviors of single large diameter bored piles, for two international codes (, 1990, and ) in addition to the Egyptian code (). The ultimate bearing capacities calculated by those codes for 38 pile case studies located in the Nile Delta and Port Said regions in Egypt are evaluated by the modified method. The main objective of this research is to compare the performance of the Egyptian code design methodology for large diameter bored piles, with the other international codes. Extensive comparisons are made between the calculations of the different codes regarding the total ultimate pile load as well as the individual contributions of the tip and skin resistances. Finally, an empirical simplified load settlement model deducted from code calculations of the ultimate load of large diameter bored piles is proposed. This model could simplify the analysis of piled raft as it can easily predict the pile settlement. The study assured that the pile load test is an irreplaceable process to estimate the ultimate pile capacity.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130674775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-01DOI: 10.1179/dfi.2013.7.2.004
A. Stuedlein, S. C. Reddy
Abstract Owing to an increasing demand to manage risk and maximize cost-effectiveness, preference for reliability-based design (RBD) over traditional deterministic design procedures has increased for deep foundation elements. In this study, factors affecting the reliability of augered cast-in-place (ACIP) piles under axial compression at the serviceability limit state (SLS) are addressed using a simple probabilistic hyperbolic model and a database of static loading tests conducted on ACIP piles in cohesionless soils. The aleatory and model uncertainty in a selected two-parameter load-displacement model is statistically characterized for use in reliability simulations. Reliability simulations incorporating the correlated bivariate model parameter distribution were generated using a statistical translational model and various parametric and non-parametric correlation coefficients to assess the effect of correlation coefficient type on the reliability simulations. The first-order reliability method (FORM) was used to determine the effect of sample size on the stability and uncertainty of the serviceability limit state reliability index. Sample sizes greater than about 40 provided relatively consistent estimates of the reliability index; however, its uncertainty continued to decrease with increasing sample sizes. A parametric study was conducted in order to determine the variables (i.e. allowable displacement, predicted pile capacity, slenderness ratio) which govern reliability. In general, the uncertainty in the model used to predict pile capacity had a more significant impact on foundation reliability compared to the uncertainty in allowable displacement; this finding illustrates one advantage of having an accurate capacity prediction model. The slenderness ratio had the largest effect on foundation reliability at the SLS, and illustrates the importance for accounting for the pile geometry in reliability assessments.
{"title":"Factors Affecting the Reliability of Augered Cast-In-Place Piles in Granular Soils at the Serviceability Limit State (DFI 2013 Young Professor Paper Competition Winner)","authors":"A. Stuedlein, S. C. Reddy","doi":"10.1179/dfi.2013.7.2.004","DOIUrl":"https://doi.org/10.1179/dfi.2013.7.2.004","url":null,"abstract":"Abstract Owing to an increasing demand to manage risk and maximize cost-effectiveness, preference for reliability-based design (RBD) over traditional deterministic design procedures has increased for deep foundation elements. In this study, factors affecting the reliability of augered cast-in-place (ACIP) piles under axial compression at the serviceability limit state (SLS) are addressed using a simple probabilistic hyperbolic model and a database of static loading tests conducted on ACIP piles in cohesionless soils. The aleatory and model uncertainty in a selected two-parameter load-displacement model is statistically characterized for use in reliability simulations. Reliability simulations incorporating the correlated bivariate model parameter distribution were generated using a statistical translational model and various parametric and non-parametric correlation coefficients to assess the effect of correlation coefficient type on the reliability simulations. The first-order reliability method (FORM) was used to determine the effect of sample size on the stability and uncertainty of the serviceability limit state reliability index. Sample sizes greater than about 40 provided relatively consistent estimates of the reliability index; however, its uncertainty continued to decrease with increasing sample sizes. A parametric study was conducted in order to determine the variables (i.e. allowable displacement, predicted pile capacity, slenderness ratio) which govern reliability. In general, the uncertainty in the model used to predict pile capacity had a more significant impact on foundation reliability compared to the uncertainty in allowable displacement; this finding illustrates one advantage of having an accurate capacity prediction model. The slenderness ratio had the largest effect on foundation reliability at the SLS, and illustrates the importance for accounting for the pile geometry in reliability assessments.","PeriodicalId":272645,"journal":{"name":"DFI Journal - The Journal of the Deep Foundations Institute","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134088260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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