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Development Of Preliminary Load And Resistance Factor Design Of Drilled Shafts In Iowa
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Book Synopsis Development of Preliminary Load and Resistance Factor Design of Drilled Shafts in Iowa by : Kam W. Ng
Download or read book Development of Preliminary Load and Resistance Factor Design of Drilled Shafts in Iowa written by Kam W. Ng and published by . This book was released on 2014 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Federal Highway Administration (FHWA) mandated utilizing the Load and Resistance Factor Design (LRFD) approach for all new bridges initiated in the United States after October 1, 2007. To achieve part of this goal, a database for Drilled Shaft Foundation Testing (DSHAFT) was developed and reported on by Garder, Ng, Sritharan, and Roling in 2012. DSHAFT is aimed at assimilating high-quality drilled shaft test data from Iowa and the surrounding regions. DSHAFT is currently housed on a project website (http://srg.cce.iastate.edu/dshaft) and contains data for 41 drilled shaft tests. The objective of this research was to utilize the DSHAFT database and develop a regional LRFD procedure for drilled shafts in Iowa with preliminary resistance factors using a probability-based reliability theory. This was done by examining current design and construction practices used by the Iowa Department of Transportation (DOT) as well as recommendations given in the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications and the FHWA drilled shaft guidelines. Various analytical methods were used to estimate side resistance and end bearing of drilled shafts in clay, sand, intermediate geomaterial (IGM), and rock. Since most of the load test results obtained from O-cell do not pass the 1-in. top displacement criterion used by the Iowa DOT and the 5% of shaft diameter for top displacement criterion recommended by AASHTO, three improved procedures are proposed to generate and extend equivalent top load-displacement curves that enable the quantification of measured resistances corresponding to the displacement criteria. Using the estimated and measured resistances, regional resistance factors were calibrated following the AASHTO LRFD framework and adjusted to resolve any anomalies observed among the factors. To illustrate the potential and successful use of drilled shafts in Iowa, the design procedures of drilled shaft foundations were demonstrated and the advantages of drilled shafts over driven piles were addressed in two case studies.
Book Synopsis Development of a Database for Drilled SHAft Foundation Testing (DSHAFT) by : Jessica A. Garder
Download or read book Development of a Database for Drilled SHAft Foundation Testing (DSHAFT) written by Jessica A. Garder and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drilled shafts have been used in the US for more than 100 years in bridges and buildings as a deep foundation alternative. For many of these applications, the drilled shafts were designed using the Working Stress Design (WSD) approach. Even though WSD has been used successfully in the past, a move toward Load Resistance Factor Design (LRFD) for foundation applications began when the Federal Highway Administration (FHWA) issued a policy memorandum on June 28, 2000.The policy memorandum requires all new bridges initiated after October 1, 2007, to be designed according to the LRFD approach. This ensures compatibility between the superstructure and substructure designs, and provides a means of consistently incorporating sources of uncertainty into each load and resistance component. Regionally-calibrated LRFD resistance factors are permitted by the American Association of State Highway and Transportation Officials (AASHTO) to improve the economy and competitiveness of drilled shafts. To achieve this goal, a database for Drilled SHAft Foundation Testing (DSHAFT) has been developed. DSHAFT is aimed at assimilating high quality drilled shaft test data from Iowa and the surrounding regions, and identifying the need for further tests in suitable soil profiles. This report introduces DSHAFT and demonstrates its features and capabilities, such as an easy-to-use storage and sharing tool for providing access to key information (e.g., soil classification details and cross-hole sonic logging reports). DSHAFT embodies a model for effective, regional LRFD calibration procedures consistent with PIle LOad Test (PILOT) database, which contains driven pile load tests accumulated from the state of Iowa. PILOT is now available for broader use at the project website: http://srg.cce.iastate.edu/lrfd/. DSHAFT, available in electronic form at http://srg.cce.iastate.edu/dshaft/, is currently comprised of 32 separate load tests provided by Illinois, Iowa, Minnesota, Missouri and Nebraska state departments of transportation and/or department of roads. In addition to serving as a manual for DSHAFT and providing a summary of the available data, this report provides a preliminary analysis of the load test data from Iowa, and will open up opportunities for others to share their data through this quality-assured process, thereby providing a platform to improve LRFD approach to drilled shafts, especially in the Midwest region
Book Synopsis Development of a Database for Drilled SHAft Foundation Testing (DSHAFT) by : Jessica A. Garder
Download or read book Development of a Database for Drilled SHAft Foundation Testing (DSHAFT) written by Jessica A. Garder and published by . This book was released on 2012 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drilled shafts have been used in the US for more than 100 years in bridges and buildings as a deep foundation alternative. For many of these applications, the drilled shafts were designed using the Working Stress Design (WSD) approach. Even though WSD has been used successfully in the past, a move toward Load Resistance Factor Design (LRFD) for foundation applications began when the Federal Highway Administration (FHWA) issued a policy memorandum on June 28, 2000.The policy memorandum requires all new bridges initiated after October 1, 2007, to be designed according to the LRFD approach. This ensures compatibility between the superstructure and substructure designs, and provides a means of consistently incorporating sources of uncertainty into each load and resistance component. Regionally-calibrated LRFD resistance factors are permitted by the American Association of State Highway and Transportation Officials (AASHTO) to improve the economy and competitiveness of drilled shafts. To achieve this goal, a database for Drilled SHAft Foundation Testing (DSHAFT) has been developed. DSHAFT is aimed at assimilating high quality drilled shaft test data from Iowa and the surrounding regions, and identifying the need for further tests in suitable soil profiles. This report introduces DSHAFT and demonstrates its features and capabilities, such as an easy-to-use storage and sharing tool for providing access to key information (e.g., soil classification details and cross-hole sonic logging reports). DSHAFT embodies a model for effective, regional LRFD calibration procedures consistent with PIle LOad Test (PILOT) database, which contains driven pile load tests accumulated from the state of Iowa. PILOT is now available for broader use at the project website: http://srg.cce.iastate.edu/lrfd/. DSHAFT, available in electronic form at http://srg.cce.iastate.edu/dshaft/, is currently comprised of 32 separate load tests provided by Illinois, Iowa, Minnesota, Missouri and Nebraska state departments of transportation and/or department of roads. In addition to serving as a manual for DSHAFT and providing a summary of the available data, this report provides a preliminary analysis of the load test data from Iowa, and will open up opportunities for others to share their data through this quality-assured process, thereby providing a platform to improve LRFD approach to drilled shafts, especially in the Midwest region
Book Synopsis Model Uncertainties in Foundation Design by : Chong Tang
Download or read book Model Uncertainties in Foundation Design written by Chong Tang and published by CRC Press. This book was released on 2021-03-16 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model Uncertainties in Foundation Design is unique in the compilation of the largest and the most diverse load test databases to date, covering many foundation types (shallow foundations, spudcans, driven piles, drilled shafts, rock sockets and helical piles) and a wide range of ground conditions (soil to soft rock). All databases with names prefixed by NUS are available upon request. This book presents a comprehensive evaluation of the model factor mean (bias) and coefficient of variation (COV) for ultimate and serviceability limit state based on these databases. These statistics can be used directly for AASHTO LRFD calibration. Besides load test databases, performance databases for other geo-structures and their model factor statistics are provided. Based on this extensive literature survey, a practical three-tier scheme for classifying the model uncertainty of geo-structures according to the model factor mean and COV is proposed. This empirically grounded scheme can underpin the calibration of resistance factors as a function of the degree of understanding – a concept already adopted in the Canadian Highway Bridge Design Code and being considered for the new draft for Eurocode 7 Part 1 (EN 1997-1:202x). The helical pile research in Chapter 7 was recognised by the 2020 ASCE Norman Medal.
Book Synopsis Load and Resistance Factor Design of Drilled Shafts Subjected to Lateral Loading at Service Limit State by : Minh Dinh Uong
Download or read book Load and Resistance Factor Design of Drilled Shafts Subjected to Lateral Loading at Service Limit State written by Minh Dinh Uong and published by . This book was released on 2018 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 2007, the American Association of State Highway Administration Officials (AASHTO) has made utilization of Load and Resistance Factor Design (LRFD) mandatory on all federally-funded new bridge projects (AASHTO, 2007). However, currently, there are no guidelines implementing LRFD techniques for design of drilled shaft subjected to lateral loads using reliability-based analysis. On a national level, the AASHTO LRFD Bridge Design Specifications (AASHTO, 2012) specify that a resistance factor of 1.0 be used for design of drilled shafts subjected to lateral loading at service limit state, which means reliability-based analyses for calibration of resistance factors have not been performed. Therefore, there is a need to create a LRFD procedure for drilled shafts subjected to lateral loading at service limit state that has reliability-based calibrated resistance factors applicable for future projects. The research focuses on the reliability-based analysis of drilled shaft subjected to lateral loading, characterize lateral load transfer model of drilled shafts in shale, probabilistic calibrate resistance factor and contribute to the development of design procedure using LRFD. The objective of this work is to improve the design of drilled shaft subjected to lateral loading using LRFD at service limit state by providing a more reliable design procedure than the current AASHTO LRFD procedure for drilled shafts subjected to lateral loading at service limit state.
Book Synopsis Drilled Shafts by : National Highway Institute (U.S.)
Download or read book Drilled Shafts written by National Highway Institute (U.S.) and published by . This book was released on 1988 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document was written as a resource for participants in a short course covering the topic of construction and design of drilled shaft foundations for bridges and other structures. It is the second edition of a Federal Highway Administration workbook on construction and design of drilled shafts. The first edition was written in 1988 (FHWA-SA-HI-88-042). While introductory material from the 1988 edition was retained, the emphasis in this document is on providing relatively comprehensive information for engineers who already have some experience with drilled shaft construction and/or design. The initial chapters cover an overview of the characteristics of drilled shafts, site investigations for drilled shafts (to collect information for both construction and design), and details of drilled shaft construction. These chapters are followed by several chapters on the design of drilled shafts in soil and rock for both axial and lateral loading, with examples. Both allowable stress design and load and resistance factor design principles are addressed. Details of design calculations procedures are provided in the appendices.
Book Synopsis Load and Resistance Factor Design of Drilled Shafts in Shale Using Standard Penetration Test and Texas Cone Penetration Test Measurements by : Mark Daniel Pierce
Download or read book Load and Resistance Factor Design of Drilled Shafts in Shale Using Standard Penetration Test and Texas Cone Penetration Test Measurements written by Mark Daniel Pierce and published by . This book was released on 2013 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Missouri Department of Transportation (MoDOT) designers currently follow American Association of State Highway and Transportation Officials (AASHTO) design methods for design of drilled shafts in shale and other weak rock. These methods are generally based on Load and Resistance Factor Design (LRFD) methods that relate uniaxial compressive strength measurements of rock cores to the side and tip resistance for drilled shafts. However, shale and other weak rock can be notoriously difficult to effectively sample and test, which poses practical problems for those tasked with designing drilled shafts in such materials. The difficulty in sampling shale has lead geotechnical engineers to consider in-situ tests, such as the Standard Penetration Test (SPT) and the Texas Cone Penetration test (TCP), as surrogates for conventional coring and laboratory testing. In order to utilize results of in-situ tests for design of drilled shafts using Load and Resistance Factor Design (LRFD), it is necessary to correlate in-situ test measurements with side and tip resistance and to establish calibrated resistance factors that account for the reliability of the correlations and the in-situ test measurements. This thesis describes efforts undertaken to develop improved correlations among in-situ test measurements and drilled shaft capacity and to develop resistance factors that produce established target reliabilities for different classes of roadways.
Book Synopsis Drilled Shafts by : Michael W. O'Neill
Download or read book Drilled Shafts written by Michael W. O'Neill and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of Recommended Resistance Factors for Drilled Shafts in Weak Rocks Based on O-Cell Tests by : Xiaoming Yang (Writer on geotechnical engineering)
Download or read book Development of Recommended Resistance Factors for Drilled Shafts in Weak Rocks Based on O-Cell Tests written by Xiaoming Yang (Writer on geotechnical engineering) and published by . This book was released on 2010 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: From October 1, 2007, the new bridges on federal-aid funded projects are mandated to be designed to meet American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications. LRFD is a simplified form of reliability-based design. By multiplying calibrated factors to load and resistance components, the designed structure will maintain a specific level of reliability (or probability of failure). By concept, the load and resistance factors should be calibrated by large number of test data; however, they are often unavailable in geotechnical engineering. Significant efforts are needed to calibrate load and resistance factors based on test data of good quality. In this study, 26 O-Cell test data were collected from Kansas, Colorado, Missouri, Ohio, and Illinois. Seven methods available in the literature were selected to estimate the load capacities of 25 out of 26 drilled shafts. The "FHWA 0.05D" method was found to yield the closest and conservative predictions of the nominal resistances to the representative values; therefore, it was adopted in this study when calibrating the resistance factors for Strength Limit State design. These test data were analyzed and used to calibrate side and base resistance factors for drilled shafts in weak rock. Resistance factors were calibrated at two different target reliability indices: 2.3 (i.e., failure probability, Pf ~ 1/100) for shafts with greater redundancy and 3.0 (Pf ~ 1/1000) for shafts with less redundancy. Side resistance factors were calibrated from two different datasets of measured resistance: total side resistance and layered unit side resistance. The resistance factors calibrated from layered unit side resistance are considered more reliable, therefore, they are recommended for design. The recommended resistance factors from this study are compared with those in AASHTO specifications. Some of those calibrated resistance factors from this study are considerably lower than those in AASHTO specifications. The main reasons for such lower resistance factors are mainly attributed to the low efficiency of the FHWA design method and the limited quality and number of O-Cell test data. These resistance factors may be improved by increasing the size and the quality of the test data in the future. At present, field load tests on drilled shafts are recommended as an alternative to using lower resistance factors, which will also accumulate more test data for future improvement.
Book Synopsis Drilled Shaft Design and Construction Guidelines Manual by : Lymon C. Reese
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:
Book Synopsis Development of a Rational Design Approach (LRFD Phi) for Drilled Shafts Considering Redundancy, Spatial Variability, and Testing Cost by : Johanna Karina Otero
Download or read book Development of a Rational Design Approach (LRFD Phi) for Drilled Shafts Considering Redundancy, Spatial Variability, and Testing Cost written by Johanna Karina Otero and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: New designs move toward larger single shaft; thus the need to improve LRFD resistance factors, and [phi] for nonredundant shaft. In general, geotechnical design practice involves analysis using representative values of design parameters (like strength, recoveries, etc.), usually an average or lowest value obtained from field and laboratory test results. It is followed by an application of a suitable factor of safety. In nature, soil parameters vary horizontally and vertically, so our research used the same soil boring parameters, but this time used information obtained from sites localized close to the design site instead using the whole site average. Random soil models were created based on geostatistics analysis using soil parameters. The created random soil models were used on a finite element program that modeled a 3-foot-diameter, 20-foot-long drilled shaft, giving the drilled shaft capacity for each random soil model and a suitable [phi] factor.
Book Synopsis Load and Resistance Factor Design of Drilled Shafts in Shale for Lateral Loading by : Andrew Boeckmann
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.
Book Synopsis Drilled Shaft Manual: Structural analysis and design for lateral loading by by : Lymon C. Reese
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.
Book Synopsis Drilled Shaft Design and Construction Guidelines Manual: Construction procedures and design for axial loading by : Lymon C. Reese
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:
Book Synopsis Load and Resistance Factor Design (LRFD) Resistance Factors for Tip Grouted Drilled Shafts by :
Download or read book Load and Resistance Factor Design (LRFD) Resistance Factors for Tip Grouted Drilled Shafts written by and published by . This book was released on 2019 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: University of South Florida researchers established Load and Resistance Factor Design (LRFD) resistance factors for postgrouted end bearing drilled shaft piles.
Book Synopsis Drilled Shafts by : Michael W. O'Neill
Download or read book Drilled Shafts written by Michael W. O'Neill and published by . This book was released on 1999 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document was written as a resource for participants in a short course covering the topic of construction and design of drilled shaft foundations for bridges and other structures. It is the second edition of a Federal Highway Administration workbook on construction and design of drilled shafts. The first edition was written in 1988 (FHWA-SA-HI-88-042). While introductory material from the 1988 edition was retained, the emphasis in this document is on providing relatively comprehensive information for engineers who already have some experience with drilled shaft construction and/or design. The initial chapters cover an overview of the characteristics of drilled shafts, site investigations for drilled shafts (to collect information for both construction and design), and details of drilled shaft construction. These chapters are followed by several chapters on the design of drilled shafts in soil and rock for both axial and lateral loading, with examples. Both allowable stress design and load and resistance factor design principles are addressed. Details of design calculations procedures are provided in the appendices.
Book Synopsis Load and Resistance Factor Design of Drilled Shafts at the Service Limit State by : Thanh Thuy Vu (Engineer)
Download or read book Load and Resistance Factor Design of Drilled Shafts at the Service Limit State written by Thanh Thuy Vu (Engineer) and published by . This book was released on 2013 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: A practical and efficient procedure for evaluation of drilled shafts at the service limit state is proposed. The procedure uses Load and Resistance Factor Design (LRFD) concepts to achieve target probabilities of failure without requiring case-specific probabilistic analyses. Proposed resistance factors are primarily dependent on four parameters: the normalized load, the coefficient of variation of the geomaterial strength, the target probability of failure, and the shaft length-to-diameter ratio. The proposed procedure can be implemented using several charts or analytical equations provided.
