Download or read book Resistance Analysis of Axially Loaded Drilled Shafts Socketed in Shale written by Terry Bryce Burkett and published by . This book was released on 2013 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation into the load-settlement behavior of two drilled shafts, founded in shale, is presented. The motivation for this research is to advance the understanding on how drilled shafts react under loading in stiff clays and shales. The objectives of the study are to measure the strengths within the subsurface material at the test site, estimate the unit side shear and unit end bearing of the shale-shaft interaction by running two axial load tests, and compare the results to the current design methods that are used to predict the axial capacity of drilled shafts. A comprehensive field investigation, performed by Fugro Consultants, provided strength profiles of the subsurface material at the test site. Through the cooperation of the Texas Department of Transportation (TxDOT), the Association of Drilled Shaft Contractors, and McKinney Drilling Company, two drilled shafts were installed at a highway construction site in Austin, Texas. The load tests were performed by Loadtest, Inc.; using the patented Osterberg-CellTM loading technique to axially displace the shafts. Ensoft, Inc. installed strain gauges at multiple levels within the shafts, making it possible to analyze the shaft mobilization during loading. Ultimate end bearing values of about 100- and 120-ksf were measured for Test Shafts #1 and #2, respectively. The current methods for estimating unit end bearing, developed by TxDOT and the Federal Highway Administration, provide fairly accurate predictions when compared to the measured information. The ultimate side resistance obtained near the O-CellTM in each test was about 20-ksf, however, the measured ultimate side resistance steadily decreased nearing the tip of the shaft. For the zones where the side resistance was believed to be fully mobilized, the TxDOT design method accurately predicts the side resistance. A limited amount of information is currently available for load tests performed in soils with TCP values harder than 2-in per 100 blows. Additional load test information should allow for a stronger correlation between TCP tests and unit resistances for very hard clay-shales, as well as, allowing for further evaluation of the shale-shaft interaction near the shaft tip. The results presented herein demonstrate the effectiveness of the current design methods for drilled shafts and the non-uniformity of side resistance within one- to two-diameters of the shaft tip.

Download or read book Analysis and Design of Axially Loaded Drilled Shafts Socketed Into Rock written by Lianyang Zhang and published by . This book was released on 1997 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Behavior of Axially Loaded Drilled Shafts in Clay shales written by Ravi P. Aurora and published by . This book was released on 1976 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Drilled Shaft Manual Construction procedures and design for axial loading written by Lymon C. Reese and published by . This book was released on 1977 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drilled shafts have been used on a limited scale for many years as an alternative to driven piles in a variety of foundation problems. However, uncertainty about the behavior of the drilled shaft has forestalled widespread adoption. The subject package, by Dr. Lymon C. Reese of the University of Texas, is intended for use by bridge engineers, geotechnical engineers, and builders of pile foundations. The manual contains rational procedures and practical guidelines for the design and construction of drilled shaft foundations. Volume I presents a rational design procedure for drilled shafts under axial loading and includes guidelines on construction methods, inspection, load testing, specifications, and cost estimates. Volume II presents alternative methods for computing the response of the shaft to lateral loading and presents the structural design of the shaft for axial and/or lateral loading.

Download or read book Drilled Shafts in Rock written by Lianyang Zhang and published by CRC Press. This book was released on 2004-05-15 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drilled shafts in rock are widely used as foundations of heavy structures such as highway bridges and tall buildings. Although much has been learned about the analysis and design of drilled shafts in rock, all the major findings are published in the form of reports and articles in technical journals and conference proceedings. This book i

Download or read book Analysis of Axially and Laterally Loaded Rock socketed Drilled Shafts with Steel Casings written by Thomas G. Lewis and published by . This book was released on 1991 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Drilled Shaft Design and Construction Guidelines Manual Construction procedures and design for axial loading written by Lymon C. Reese and published by . This book was released on 1977 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Drilled Shaft Manual Structural analysis and design for lateral loading by written by Lymon C. Reese and published by . This book was released on 1977 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drilled shafts have been used on a limited scale for many years as an alternative to driven piles in a variety of foundation problems. However, uncertainty about the behavior of the drilled shaft has forestalled widespread adoption. The subject package, by Dr. Lymon C. Reese of the University of Texas, is intended for use by bridge engineers, geotechnical engineers, and builders of pile foundations. The manual contains rational procedures and practical guidelines for the design and construction of drilled shaft foundations. Volume I presents a rational design procedure for drilled shafts under axial loading and includes guidelines on construction methods, inspection, load testing, specifications, and cost estimates. Volume II presents alternative methods for computing the response of the shaft to lateral loading and presents the structural design of the shaft for axial and/or lateral loading.

Download or read book Drilled Shaft Design and Construction Guidelines Manual written by Lymon C. Reese and published by . This book was released on 1977 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of Side Shear Stress Development for Drilled Shafts in Very Weak Porous Limestone Using Axial Load Transfer Analyses written by Matias R. Frediani and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a series of axial load transfer analyses performed to investigate the mobilization of side shear stresses of drilled shafts installed in a very weak, porous limestone formation in Puerto Rico (PR). The numerical analyses presented are predictions of two axial load tests carried out on instrumented drilled shafts installed in very weak, porous limestone at a test site located in northwest PR. The field test component was performed by a former MS student of the research group of Dr. Pando when employed by the University of Puerto Rico at MayaguÌ8ez. The test site involved an outcrop of a very weak, porous, and highly weathered limestone with a representative unconfined compressive strength (UCS) of 2.7 MPa, and an average rock quality designation (RQD) of 34%. Descriptions of the test site and the rock characterization are provided in this MS thesis. The main objective of this thesis was to investigate the mobilization of the side shear stresses of the two test drilled shafts installed in this unique very weak, porous limestone and assess whether load transfer analyses are suitable to predict the observed experimental behavior. The first focus of this study was to evaluate whether existing static methods could reasonably predict the measured ultimate side shear stresses, also referred to as unit shaft resistance. A total of 10 static methods were evaluate and the range of predictions of the unit shaft resistance was found to be very large, highlighting the need to improve our capability of predicting this important design parameter. Furthermore, the measured ultimate side shear stress values at the PR test site were found to be above the upper bound of the range of predicted values using the selected static methods. The higher measured unit shaft resistance values are attributed to limitation of the selected static methods that are solely based on only the intact rock UCS, and do not incorporate other important variables such as the surface roughness of the rock socket walls or stiffness ratio between drilled shaft and surrounding rock mass. The second focus of this MS thesis was to evaluate the ability to capture the axial load transfer mechanisms of the test drilled shafts and the experimental axial load versus settlement curves using load transfer analyses. The load transfer analyses behavior of the axial load tests was simulated using 1D finite element models of the deep foundation and springs using nonlinear T-Z curves to represent the development of the side shear stresses as a function of level of relative movement between the foundation and the rock. The literature review identified two T-Z curves formulations for very weak limestone. One formulation is from McVay and Niraula (2004) who proposed T-Z curves developed from centrifuge tests on simulated Florida limestone. The second formulation is a model developed by Asem and Gardoni (2019) based on a comprehensive database of drilled shaft load tests on very weak to weak rock. These two T-Z formulations were used to predict the experimental load-settlement curves. The predictions using the McVay and Niraula (2004) were much stiffer than the observed behavior. A modified T-Z formulation, based on the Asem and Gardoni (2019) was found to yield the best predictions and exhibit more flexibility because it depends not only on the unit shaft resistance but also on the stiffness or modulus of deformation of the rock mass. The modified load-transfer model was found to be reasonably adequate to predict the measured experimental behavior of the two test drilled shafts installed in the unique, very weak, porous limestone rock from the karst formation in northwest PR.

Download or read book Design of Rock Socketed Drilled Shafts written by Jamal Nusairat and published by . This book was released on 2006 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project was aimed at evaluating and developing design methods for laterally loaded drilled shafts socketed in rock. Five lateral load tests on rock socketed drilled shafts with full range of instrumentation were conducted in Ohio. Detailed instrumentation included the use of vibrating wire strain gages, inclinometers, dial gages, and load cells. P-y curves representing site-specific lateral shaft-rock interaction were deduced from strain data. Field testing included the use of a borehole pressuremeter/dilatometer to obtain measurements that were correlated with rock mass strength and deformation parameters as well as with p-y curves. A comparison was made between the baseline p-y curves deduced from strain data of lateral load tests, the p-y curves predicted by using Reese's interim criterion, and the p-y curves from the pressuremeter tests in rock. A new hyperbolic p-y criterion for rock is proposed based on the field test data and extensive theoretical work. Validation of the proposed p-y criterion of rock was carried out by comparing the predictions of shaft deflections and bending moments using the hyperbolic p-y criterion against actual lateral load tests results. Based on the findings of this study, a complete solution for the design of drilled shafts socketed in rock or intermediate geomaterials under lateral loads is provided.

Download or read book Load and Resistance Factor Design of Drilled Shafts in Shale for Lateral Loading written by Andrew Boeckmann and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A research project involving 32 drilled shaft load tests was undertaken to establish LRFD procedures for design of drilled shafts subjected to lateral loads. Tests were performed at two Missouri Department of Transportation (MoDOT) geotechnical research sites. All shafts were founded in shale. Shafts were instrumented to measure the displacement of the shaft head, and the structural response of each shaft was interpreted from strain gage data as well as from ShapeAccelArray (SAA) data. The load tests achieved significant displacement of the top of the shaft, and successfully transferred load into the rock layers.

Download or read book Analysis of Laterally Loaded Drilled Shafts in Rock written by Ke Yang and published by . This book was released on 2006 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drilled shafts socketed into rock are widely used as foundations for bridges and other important structures. Rock-socketed drilled shafts are also used to stabilize a landslide. The main loads applied on the drilled shafts are axial compressive or uplift loads as well as lateral loads with accompanying moments. Although there exist several analysis and design methods especially for rock-socketed drilled shafts under lateral loading, these methods were developed with assumptions without actual validations with field load test results. Some of the methods have been found to provide unsafe designs when compared to recently available field test data. Therefore, there is a need to develop a more rational design approach for laterally loaded drilled shafts socketed in rock. A hyperbolic non-linear p-y criterion for rock is developed in this study that can be used in conjunction with existing computer programs, such as COM624P, LPILE, and FBPIER, to predict the deflection, moment, and shear responses of a shaft under the applied lateral loads. Considerations for the effects of joints and discontinuities on the rock mass modulus and strength are included in the p-y criterion. Evaluations based on comparisons between the predicted and measured responses of full-scale lateral load tests on fully instrumented drilled shafts have shown the applicability of the proposed p-y criterion and the associated methods for determining the required input of rock parameters. In addition to the development of a hyperbolic p-y criterion for rock, a method for predicting lateral capacities of drilled shafts in rock and/or soils is developed for assessing the safety margin of the designed shafts against the design loads. A computer program LCPILE is developed using VC++ to facilitate computations. An elastic solution based on a variational approach is also developed for determining drilled shaft elastic deflection due to applied lateral loads in a two-layer soil layer system. The computational algorithm was coded in a Mathematical file for easy application. Finally, Briaud's method for deriving p-y curves of rock from pressuremeter or dilatometer test results is evaluated using available field test data. A modification to the Briaud's method is recommended for applications in rocks.

Download or read book Analy s is and Design of Drilled Shafts in Rock written by Lianyang Zhang and published by . This book was released on 1999 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Drilled Shaft Design and Construction Guidelines Manual Reese L C and Allen J D Structural analysis and design for lateral loading written by Lymon C. Reese and published by . This book was released on 1977 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calibration of Resistance Factors for Drilled Shafts for the New FHWA Design Method written by Murad Yusuf Abu-Farsakh and published by . This book was released on 2013 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a continuing effort to implement the Load and Resistance Factor Design (LRFD) design methodology for deep foundations in Louisiana, this report will present the reliability-based analyses for the calibration of the resistance factor for LRFD design of axially loaded drilled shafts using Brown et al. method (2010 FHWA design method). Twenty-six drilled shaft tests collected from previous research (LTRC Final Report 449) and eight new drilled shaft tests were selected for statistical reliability analysis; the predictions of total, side, and tip resistance versus settlement behavior of drilled shafts were established from soil borings using both 1999 FHWA design method (Brown et al. method) and 2010 FHWA design method (O'Neill and Reese method). The measured drilled shaft axial nominal resistance was determined from either the Osterberg cell (O-cell) test or the conventional top-down static load test. For the 30 drilled shafts that were tested using O-cells, the tip and side resistances were deduced separately from test results. Statistical analyses were performed to compare the predicted total , tip, and side drilled shaft nominal axial resistance with the corresponding measured nominal resistance.

Download or read book Improvement of the Geotechnical Axial Design Methodology for Colorado s Drilled Shafts Socketed in Weak Rocks written by Naser Abu-Hejleh and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As a part of the construction requirements for the T-REX and I-25/Broadway projects along I-25 in Denver, Colorado, four Osterberg (O-Cell) load tests on drilled shafts were performed in 2002. The bedrock at the load test sites represents the range of typical claystone and sandstone (soft to very hard) encountered in the Denver metro area. To maximize the benefits of this work, the O-Cell load test results and information on the construction and materials of the test shafts were documented, and an extensive program of simple geotechnical tests was performed on the weak rock at the load test sites. This includes standard penetration tests, strength tests, and pressuremeter tests. The analysis of the test data and information and experience gained in this study were employed to provide: 1) best correlation equations between results of various simple geotechnical tests; 2) best-fit design equations to predict the shaft ultimate unit base and side resistance values, and the load-settlement curve as a function of the results of simple geotechnical tests; and 3) assessment of the CDOT and AASHTO design methods.