Development of LRFD Procedures for Bridge Piles in Iowa PDF Download

Author:
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 149

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Book Description
With the goal of producing engineered foundation designs with consistent levels of reliability as well as fulfilling the Federal Highway Administration (FHWA) mandate that all new bridges initiated after October 1, 2007 be designed according to the Load and Resistance Factor Design (LRFD) approach, the Iowa Highway Research Board (IHRB) sponsored three research projects on driven piles (TR-573, -583 and -584). The research outcomes are presented in three reports entitled Development of LRFD Design Procedures for Bridge Piles in Iowa, Volumes I, II, and III, and other research information is available on the project web site at http://srg.cce.iastate.edu/lrfd/. Upon incorporating the regional LRFD recommendations from the completed research into the Iowa DOT Bridge Design Manual (2010) as it is being rewritten under the new title of LRFD Bridge Design Manual (December 2011), and adopting the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications (2010), this Volume IV for driven piles in Iowa was developed. Following the layout of a design guide, the application of the LRFD approach is demonstrated using various pile design examples in three different tracks, which depend on the construction control method used for establishing the pile driving criteria. Piles are designed using the Iowa Blue Book method. The pile driving criteria are established using the Wave Equation Analysis Program (WEAP) and the Pile Driving Analyzer (PDA) with a subsequent pile signal matching analysis using the CAse Pile Wave Analysis Program (CAPWAP) in Track 3. The track examples cover various pile types, three different soil profiles (cohesive, non-cohesive, and mixed) and special design considerations (piles on rock, scouring, downdrag, and uplift).

Author:
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 286

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Book Description
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. As a result, there has been a progressive move among state Departments of Transportation (DOTs) toward an increased use of the LRFD in geotechnical design practices. For the above reasons, the Iowa Highway Research Board (IHRB) sponsored three research projects: TR-573, TR-583 and TR-584. The research information is summarized in the project web site (http://srg.cce.iastate.edu/lrfd/). Two reports of total four volumes have been published. Report volume I by Roling et al. (2010) described the development of a user-friendly and electronic database (PILOT). Report volume II by Ng et al. (2011) summarized the 10 full-scale field tests conducted throughout Iowa and data analyses. This report presents the development of regionally calibrated LRFD resistance factors for bridge pile foundations in Iowa based on reliability theory, focusing on the strength limit states and incorporating the construction control aspects and soil setup into the design process. The calibration framework was selected to follow the guidelines provided by the American Association of State Highway and Transportation Officials (AASHTO), taking into consideration the current local practices. The resistance factors were developed for general and in-house static analysis methods used for the design of pile foundations as well as for dynamic analysis methods and dynamic formulas used for construction control. The following notable benefits to the bridge foundation design were attained in this project: 1) comprehensive design tables and charts were developed to facilitate the implementation of the LRFD approach, ensuring uniform reliability and consistency in the design and construction processes of bridge pile foundations; 2) the results showed a substantial gain in the factored capacity compared to the 2008 AASHTO-LRFD recommendations; and 3) contribution to the existing knowledge, thereby advancing the foundation design and construction practices in Iowa and the nation.

Author:
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages :

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Book Description
For well over 100 years, the Working Stress Design (WSD) approach has been the traditional basis for geotechnical design with regard to settlements or failure conditions. However, considerable effort has been put forth over the past couple of decades in relation to the adoption of the Load and Resistance Factor Design (LRFD) approach into geotechnical design. With the goal of producing engineered designs with consistent levels of reliability, the Federal Highway Administration (FHWA) issued a policy memorandum on June 28, 2000, requiring all new bridges initiated after October 1, 2007, to be designed according to the LRFD approach. Likewise, regionally calibrated LRFD resistance factors were permitted by the American Association of State Highway and Transportation Officials (AASHTO) to improve the economy of bridge foundation elements. Thus, projects TR-573, TR-583 and TR-584 were undertaken by a research team at Iowa State University's Bridge Engineering Center with the goal of developing resistance factors for pile design using available pile static load test data. To accomplish this goal, the available data were first analyzed for reliability and then placed in a newly designed relational database management system termed PIle LOad Tests (PILOT), to which this first volume of the final report for project TR-573 is dedicated. PILOT is an amalgamated, electronic source of information consisting of both static and dynamic data for pile load tests conducted in the State of Iowa. The database, which includes historical data on pile load tests dating back to 1966, is intended for use in the establishment of LRFD resistance factors for design and construction control of driven pile foundations in Iowa. Although a considerable amount of geotechnical and pile load test data is available in literature as well as in various State Department of Transportation files, PILOT is one of the first regional databases to be exclusively used in the development of LRFD resistance factors for the design and construction control of driven pile foundations. Currently providing an electronically organized assimilation of geotechnical and pile load test data for 274 piles of various types (e.g., steel H-shaped, timber, pipe, Monotube, and concrete), PILOT (http://srg.cce.iastate.edu/lrfd/) is on par with such familiar national databases used in the calibration of LRFD resistance factors for pile foundations as the FHWA's Deep Foundation Load Test Database. By narrowing geographical boundaries while maintaining a high number of pile load tests, PILOT exemplifies a model for effective regional LRFD calibration procedures.

Author:
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 207

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Book Description
In response to the mandate on Load and Resistance Factor Design (LRFD) implementations by the Federal Highway Administration on all new bridge projects initiated after October 1, 2007, the Iowa Highway Research Board sponsored these research projects to develop regional LRFD recommendations. The LRFD development was performed using the Iowa Department of Transportation Pile Load Test database. To increase the data points for LRFD development, develop LRFD recommendations for dynamic methods, and validate the results of LRFD calibration, 10 full-scale field tests on the most commonly used steel H-piles were conducted throughout Iowa. Detailed in situ soil investigations were carried out, push-in pressure cells were installed, and laboratory soil tests were performed. Pile responses during driving, at the end of driving, and at re-strikes were monitored using the Pile Driving Analyzer, following with the CAse Pile Wave Analysis Program analysis. The hammer blow counts were recorded for Wave Equation Analysis Program and dynamic formulas. Static load tests were performed and the pile capacities were determined based on the Davisson's criteria. The extensive experimental research studies generated important data for analytical and computational investigations. The SLT measured load-displacements were compared with the simulated results obtained using a model of the TZPILE program and using the modified borehole shear test method. Two analytical pile setup quantification methods, in terms of soil properties, were developed and validated. A new calibration procedure was developed to incorporate pile setup into LRFD.

Author: Chong Tang
Publisher: CRC Press
ISBN: 0429655959
Category : Technology & Engineering
Languages : en
Pages : 497

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Book Description
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.

Author: Kam W. Ng
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 232

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Book Description
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.

Author: Iowa. Highway Research Board
Publisher:
ISBN:
Category : Highway research
Languages : en
Pages : 106

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Author: Aaron S. Budge
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 514

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Driven piles are the most common foundation solution used in bridge construction (Paikowsky et al., 2004). Their safe use requires to reliable verification of their capacity and integrity. Dynamic analyses of driven piles are methods attempting to obtain the static capacity of a pile, utilizing its behavior during driving. Dynamic equations (aka pile driving formulas) are the earliest and simplest forms of dynamic analyses. The development and the examination of such equation tailored for MnDOT demands is presented. In phase I of the study reported by Paikowsky et al. (2009, databases were utilized to investigate previous MnDOT (and other) dynamic formulas and use object oriented programming for linear regression to develop a new formula that was then calibrated for LRFD methodology and evaluated for its performance. This report presents the findings of phase II of the study in which a comprehensive investigation of the Phase I findings were conducted. The studies lead to the development of dynamic formulae suitable for MnDOT foundation practices, its calibrated resistance factors and its application to concrete and timber piles. Phase II of the study also expanded on related issues associated with Wave Equation analyses and static load tests, assisting the MnDOT in establishing requirements and specifications.

Author: Fei Han
Publisher:
ISBN: 9781622604043
Category :
Languages : en
Pages :

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Pile group foundations are used in most foundation solutions for transportation structures. Rigorous and reliable pile design methods are required to produce designs whose level of safety (probability of failure) is known. By utilizing recently developed, advanced, two-surface plasticity constitutive models, rigorous finite element analyses are conducted. These analyses are for axially loaded single piles and pile groups with several pile-to-pile distances in various group configurations installed in sandy and clayey soil profiles. The analyses shed light on the relationships between the global response of the pile-soil system (development of shaft and base resistances) and the behavior of local soil elements (e.g., shear band formation). The influence of the group configuration, pile-topile spacing, soil profile, and pile head settlement on the group effects are studied. Mechanisms of pile-soil-pile interactions in pile groups are revealed. Pile efficiencies for individual piles and the overall pile group are reported for use in pile group design. The instrumentation, installation, and static and dynamic testing of a closed-ended, driven pipe pile in Marshall County, Indiana is documented. The test results along with two other case histories are used to verify the new Purdue pile design method. Probabilistic analyses are performed to develop resistance factors for the load and resistance factor design, LRFD, of vii pile groups considering both displacement and non-displacement piles, various soil profiles, and two target probabilities of failure. The pile design equations, pile group efficiencies and resistance factors together form the LRFD pile design framework. Two step-by-step design examples are provided to demonstrate the LRFD pile design procedures for single piles and pile groups.

Author: Joseph Ronson Cravens
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 332

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Book Description
"The Missouri Department of Transportation (MoDOT) has recently migrated from allowable stress design (ASD) to load and resistance factor design (LRFD) of driven piles. This transition was initiated when the Federal Highway Administration (FHWA) issued a policy stating that all new bridge designs shall be designed in accordance with the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications to eliminate the difference in design methodologies for bridge superstructures and bridge substructures. However, the resistance factors for driven piles specified in the AASHTO LRFD specifications are based on nationwide pile data, consisting of a wide range of different geologies, subsurface conditions, and installation procedures. For MoDOT to fully benefit from the transition from ASD to LRFD, resistance factors based on MoDOT's local practices and geologic conditions must be developed. The presented research was dedicated to collecting pile load test data to allow the calibration of resistance factors for ultimate limit state design for predictive methods used by MoDOT to determine pile capacity, as well as to develop related reliability-based quality control criteria of driven pile foundations. MoDOT's current state of practice was evaluated and all available pile load test data was collected. However, MoDOT has records for only 10 pile load tests. Therefore, the search was extended to Missouri's eight neighboring states by distributing questionnaires to surrounding state transportation administrations in hope of gathering pile data. Surrounding states have different geologic conditions, but any collected pile data could be matched to similar soil and rock formations in Missouri's geologic regions. Only five out of eight states responded to the questionnaire, and there was no pile load test data obtained from the states that responded. Therefore, the calibration of resistance factors could not be performed based on the research approaches. The deformation behavior of MoDOT bridge pile foundations was also evaluated at the serviceability limit state by modeling pile foundations in FB-MultiPier. The results indicated that pile displacement is an important factor for the development of serviceability resistance factors for pile foundations. Lastly, recommendations for future MoDOT practice and future research efforts regarding driven piles are provided"--Abstract, leaf iii.