Author: Matthew Garry Stuckmeyer
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 132
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Book Description
"A static pile load test program was initiated by the Missouri Department of Transportation (MoDOT) to evaluate the use of pile load tests in Missouri LRFD guidelines. The program's approach involves two phases to achieve the appropriate levels of reliability for driven piles in the state of Missouri. This thesis focuses on the data collection efforts of Phase 1. Two quick static pile load tests were performed to failure on test piles in the Southeast Lowlands geologic region of Missouri. The piles were dynamically monitored during installation and subsequent restrike tests performed. The results of the static and dynamic pile testing were evaluated and interpreted. Overall, the nominal resistances predicted by dynamic tests (CAPWAP) at beginning of restrike (BOR) compared well to the results of the static load tests evaluated using Davisson's method (at these specific sites). A comparison of the load transfer distributions from the dynamic and static load tests provided mixed results. The effects of pile set-up after driving are a significant factor to consider in determining the need for a restrike. The additional resistance available following pile setup can have a substantial effect on the nominal resistance determined using dynamic methods. When BOR capacities are measured using dynamic methods they can be used with confidence for the calibration of resistance factors with respective pile types and geologic units. Available pile load test data sets from Missouri's neighboring states and previous efforts conducted in Missouri were compiled as well. Two recently available pile load test databases were evaluated and considered for the upcoming phase to conduct calibration of resistance factors."--Abstract, page iii.
Author:
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages :
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Book Description
This research studied the use of pile load tests for the development of resistance factors in the LRFD design specifications currently adopted by the Missouri DOT. To this end, three (3) bridge sites were identified to conduct a pile load test in conjunction with the normal bridge contracting activities. This allowed a side by side comparisons with production piles and the impact to the design. Since most of the issues with pile driving and pile capacities are for friction piles that require dynamic testing, the pile load tests locations were selected in geologic regions with relatively deep firm ground or bedrock. In this way, an end bearing condition was avoided. Two sites were selected in the Southeastern Lowlands region and one in the Northern Glaciated Plains region. The pile load tests yielded high resolution data for both the load capacity and load transfer distributions. The different pile and soil types produced different degrees of pile setup and these conditions were examined with a series of restrikes, as necessary. Full displacement piles in overconsolidated clays had unexpected results and the highest restrike capacities comp ared to the other sites. All the static and dynamic pile load tests produced capacities higher than the ones estimated by the design engineers. The resistance factors back calculated based on the pile load test data generated higher resistance factors than the 0.65 suggested by AASHTO LRFD specifications. Additionally, pile load tests data from other sources in Missouri and the neighboring states were collected and compiled for future use by the Missouri DOT.
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.
Author: Dan A. Brown
Publisher: Transportation Research Board
ISBN: 0309143357
Category : Technology & Engineering
Languages : en
Pages : 518
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Book Description
TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 418: Developing Production Pile Driving Criteria from Test Pile Data provides information on the current practices used by state transportation agencies to develop pile driving criteria, with special attention paid to the use of test pile data in the process.
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: Mulugeta Abay Kebede
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 270
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Book Description
"Over the past two decades the load resistance factor design (LRFD) has been accepted by the American Association for Transportation and Highway Officials (AASHTO) for the design of bridges. This approach is now gaining widespread popularity in the United States for substructure bridge design, including the design of driven pile foundations, as the states calibrate the geotechnical resistance factors for local geological conditions and practices. This study presents the geotechnical resistance factors calibrated for axially driven pile using the first-order reliability method (FORM) for the target reliability index of 2.33 and 3.0 based on 64 end-of-drives (EOD) and 22 beginning-of restrike (BOR) pile driving analyzer (PDA) test data from nine bridge sites in Missouri. Three static pile capacity prediction methods were used, i.e. the Nordlund, Meyerhof and Beta methods. The work investigated the efficiency of each method based on the bias factor, the ratio of the measured to the predicted capacity of the pile, ([lambda] = R[subscript m]/R[subscript p]), the coefficient of variation (COV), and efficiency factor or the ratio of the resistance factor to the bias factor, ([phi]/[lambda]). It verified that the Beta and Nordlund methods provide better predictions than the Meyerhof method. In addition, a comparison of the resistance factor in current AASHTO LRFD with the calibrated resistance factor shows that validating the resistance factors in the AASHTO may result in less reliable design. Finally, the recommended resistance factors for LRFD design are provided for use in Missouri. In addition, further refinement of the developed resistance factors is recommended to improve the resistance factors using large quantity and high quality of data that cover wide areas the glaciated plain and southeast lowland geological regions"--Abstract, leaf iii.
Author: Aaron S. Budge
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 514
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Book Description
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:
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:
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: Robert Y. Liang
Publisher:
ISBN:
Category : Piling (Civil engineering)
Languages : en
Pages : 244
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Book Description
Driven piles are widely used as foundations to support buildings, bridges, and other structures. In 2007, AASHTO has adopted LRFD method for foundation design. The probability based LRFD approach affords the mathematical framework from which significant improvements on the design and quality control of driven piles can be achieved. In this research, reliability-based quality control criteria for driven piles are developed based on the framework of acceptance-sampling analysis for both static and dynamic test methods with the lognormal distribution characteristics. As a result, an optimum approach is suggested for the number of load tests and the required measured capacities for quality control of driven piles. Furthermore, this research has compiled a large database of pile set-up, from which the reliability-based approach of FORM is employed to develop separate resistance factors for the measured reference (initial) capacity and predicted set-up capacity. This report also provides a Bayesian theory based approach to allow for combining the information from the static pile capacity calculation and dynamic pile testing data to improve pile design process. Specifically, the results from dynamic pile tests can be utilized to reduce the uncertainties associated with static analysis methods of pile capacity by updating the corresponding resistance factors. This research has also developed one-dimensional wave equation based algorithm to interpret the High Strain Testing (HST) data for the estimation of the shaft and toe resistance of driven piles. The closed form solution is obtained for determining the Smith damping factor and the static soil resistance. Finally, a set of new wireless dynamic testing equipment (both hardware and software) is developed for more efficient dynamic pile testing.
