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Reed L. Mosher - One of the best experts on this subject based on the ideXlab platform.
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Sheet Pile Tensions in Cellular Structures
Journal of Geotechnical and Geoenvironmental Engineering, 2003Co-Authors: Kord J. Wissmann, Reed L. Mosher, George M. Filz, James R. MartinAbstract:Cellular structures constructed of interlocking steel sheet piles are used in marine environments as Cofferdams, bulkheads, mooring dolphins, and lock guide walls. In addition to providing safety against sliding, bearing failure, overturning, and tilting, cellular structures must also be designed to prevent sheet pile interlock rupture, which can lead to catastrophic failure if the cell fill is lost. Methods commonly used to estimate sheet pile interlock tensions were developed in the 1940s, 1950s, and 1970s. These methods are based on empirical observations, and they do not explicitly account for soil–structure interactions. This paper presents the results of finite element analyses and instrumentation measurements performed to examine soilstructure interaction effects on sheet pile tensions. The finite-element analyses were used to compute sheet pile tensions at five instrumented cells, and the results are compared with measurements. The calibrated finite-element model was then used to investigate the effects of varying cell geometry, interlock behavior, sheet pile penetration depth, and foundation stiffness on sheet pile tensions. The instrumentation measurements provide data for estimating changes in sheet pile tensions due to cell fill densification, cofferdam unwatering, and bulkhead backfilling.
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three dimensional finite element analysis of sheet pile cellular Cofferdams
This Digital Resource was created from scans of the Print Resource, 1992Co-Authors: Reed L. MosherAbstract:Abstract : The conventional design methods for sheet-pile cellular Cofferdams were developed in the 1940's and 1950's based on field and limited experimental observations. The analytical techniques of the day were unable to account for the complexities involved. The procedures used only rudimentary concepts of soil-structure interaction which do not exhibit the true response of the cofferdam for most circumstances. During the past decade it has been demonstrated that with proper consideration of the soil-structure interaction effects, the two-dimensional finite element models can be powerful tools in the investigation of cellular cofferdam behavior. However, universal implementation of the findings of these analyses was difficult to justify, since uncertainties remain about the assumptions made in arriving at the two-dimensional models. The only way to address these uncertainties was to perform a three-dimensional analysis. This investigation has focused on the study of the three-dimensional behavior of Lock and Dam No. 26 (R) sheet-pile cellular cofferdam. The work involved the development of a new three-dimensional soil-structure interaction finite element code for cellular cofferdam modeling, and the application of the new code to the study of the behavior of the first- and second-stage cofferdam at Lock and Dam No. 26 (R). The new code was used to study the cell filing process where the main cell is filled first with the subsequent filling of the arc cell.
D Waite - One of the best experts on this subject based on the ideXlab platform.
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THE DESIGN AND CONSTRUCTION OF SHEET-PILED Cofferdams
1993Co-Authors: B P Williams, D WaiteAbstract:This report brings together information from many sources, which is likely to be needed for the successful design and construction of steel sheet-piling Cofferdams up to ten metres deep. It recommends considering the use of Cofferdams at the initial project planning stage, so that site investigation can be arranged to provide the information necessary for their design. Other topics covered include: (1) the conceptual design of sheet pile Cofferdams; (2) wall designs; (3) support system designs; (4) the construction, maintenance, and removal of a cofferdam; (5) soil and water pressures on a retaining wall; (6) examples of UK safety regulations; and (7) dimensions and properties of steel sheet piles manufactured in the UK. Worked examples are given for: (1) the design of a sheet pile wall for a cofferdam; (2) the design of an internal frame for a cofferdam; (3) the use of a flow net diagram; and (4) earth pressures for layered ground with non-uniform slopes. The considerable effects of water pressures on cofferdam loadings are emphasised, and various methods of calculating these pressures are given. There are many checklists and comprehensive references to relevant literature.
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the design and construction of sheet piled Cofferdams ciria special publication 95
1993Co-Authors: B P Williams, D WaiteAbstract:This report presents the latest good practice on the planning, design, construction, maintenance, and removal of steel sheet pile Cofferdams as used for the support of temporary excavations. The considerable effect that water pressures have on loading on the cofferdam wall is emphasized.
Velásquez Pérez Alejandro - One of the best experts on this subject based on the ideXlab platform.
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Influence of concrete material time-dependency and temperature on the performance of a cofferdam structure braced with braces with reinforces concrete ring beams
2017Co-Authors: Velásquez Pérez AlejandroAbstract:Asbstract: The lateral load resisting system of tall buildings is often made of reinforced concrete shear walls that are constructed using a cofferdam structure. The term cofferdam, often used in offshore applications, is employed in this research as a temporary watertight structure made of steel sheet piles and internally braced with steel or reinforced concrete ring beams to retain the surrounding soil. The soil removal inside of the cofferdam, necessary to install the foundations of the concrete core in rock or competent soil, is typically performed following a bottom-up excavation sequence. The performance of these type of systems in urban environments is critical as excessive excavation-induced ground movements can lead to significant damage of adjacent infrastructure. In this research, concrete material time-dependent and temperature-dependent effects of shrinkage, creep, and aging of concrete ring beam bracings are shown to have contributed to the lateral deformations of an urban cofferdam built for a structure that was projected as the tallest building in America. It is shown that because of the very low stiffness of perimeter steel sheet piles, the performance of these Cofferdams is highly influenced by the quality control and adequate curing of the concrete material of the ring beams used as the internal lateral bracing system of the cofferdam. It is also shown with actual performance data how the sequence and timing of cycles of excavation and lateral bracing highly impacted the performance. The concrete material time-dependent effects presented in this research have not been incorporated as an integral part of the analysis and design of these temporary structures in urban environments and ignoring these effects conceal the fundamental reason for the resulting lateral deformations of these structures. Keywords: Cofferdam, bottom-up construction, field performance, concrete time-effects, concrete temperature-effectsResumen: Los sistemas de contención para cargas laterales de edificios altos son comúnmente hechos con muros de concreto construidos a partir de ataguías. Las ataguías son normalmente usadas para aplicaciones costeras, la empleada en esta investigación fue usada como una estructura temporal impermeable construida con tablestacas de acero y arriostrada internamente por anillos de acero o concreto reforzado para soportar el suelo alrededor. El proceso de excavación dentro de la ataguía necesario para instalar las fundaciones del núcleo rígido de concreto en roca o suelo competente, es típicamente realizado a partir de una excavación descendente-ascendente. El desempeño de este tipo de estructura en un ambiente urbano es crítico, pues movimientos del suelo alrededor inducidos por la excavación pueden llevar a daños significativos en estructuras cercanas. En esta investigación se muestran como los efectos en el tiempo y de la temperatura del concreto: contracción, repteo y madurez han contribuido a deformaciones laterales en una ataguía urbana construida para el edificio proyectado como el más alto de América. Se muestra como por la baja rigidez del tablestacado perimetral de acero, las deformaciones de la ataguía son altamente dependientes del control de calidad y del curado del concreto reforzado empleado para el arrostramiento interno con anillos perimetrales. También se presenta con instrumentación de campo como la secuencia constructiva y los tiempos de los ciclos de excavación impactaron altamente el desempeño de la estructura. Los efectos del concreto, dependientes del tiempo y la temperatura que son tratados en esta investigación no son tenidos en cuenta de forma integral en los análisis y durante la etapa de diseño, ignorar estos efectos es la principal razón de las deformaciones laterales resultantes de estas estructuras. Palabras clave: ataguía, construcción descendente-ascendente, desempeño en campo, efectos del tiempo del concreto, efectos de la temperatura del concret
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Influence of concrete material time-dependency and temperature on the performance of a cofferdam structure braced with reinforced concrete ring beams
2016Co-Authors: Velásquez Pérez AlejandroAbstract:The lateral load resisting system of tall buildings is often made of reinforced concrete shear walls that are constructed using a cofferdam structure. The term cofferdam, often used in offshore applications, is employed in this research as a temporary watertight structure made of steel sheet piles and internally braced with steel or reinforced concrete ring beams to retain the surrounding soil. The soil removal inside of the cofferdam, necessary to install the foundations of the concrete core in rock or competent soil, is typically performed following a bottom-up excavation sequence. The performance of these type of systems in urban environments is critical as excessive excavation-induced ground movements can lead to significant damage of adjacent infrastructure. In this research, concrete material time-dependent and temperature-dependent effects of shrinkage, creep, and aging of concrete ring beam bracings are shown to have contributed to the lateral deformations of an urban cofferdam built for a structure that was projected as the tallest building in America. It is shown that because of the very low stiffness of perimeter steel sheet piles, the performance of these Cofferdams is highly influenced by the quality control and adequate curing of the concrete material of the ring beams used as the internal lateral bracing system of the cofferdam. It is also shown with actual performance data how the sequence and timing of cycles of excavation and lateral bracing highly impacted the performance. The concrete material time-dependent effects presented in this research have not been incorporated as an integral part of the analysis and design of these temporary structures in urban environments and ignoring these effects conceal the fundamental reason for the resulting lateral deformations of these structures.Resumen: Los sistemas de contención para cargas laterales de edificios altos son comúnmente hechos con muros de concreto construidos a partir de ataguías. Las ataguías son normalmente usadas para aplicaciones costeras, la empleada en esta investigación fue usada como una estructura temporal impermeable construida con tablestacas de acero y arriostrada internamente por anillos de acero o concreto reforzado para soportar el suelo alrededor. El proceso de excavación dentro de la ataguía necesario para instalar las fundaciones del núcleo rígido de concreto en roca o suelo competente, es típicamente realizado a partir de una excavación descendente-ascendente. El desempeño de este tipo de estructura en un ambiente urbano es crítico, pues movimientos del suelo alrededor inducidos por la excavación pueden llevar a daños significativos en estructuras cercanas. En esta investigación se muestran como los efectos en el tiempo y de la temperatura del concreto: contracción, repteo y madurez han contribuido a deformaciones laterales en una ataguía urbana construida para el edificio proyectado como el más alto de América. Se muestra como por la baja rigidez del tablestacado perimetral de acero, las deformaciones de la ataguía son altamente dependientes del control de calidad y del curado del concreto reforzado empleado para el arrostramiento interno con anillos perimetrales. También se presenta con instrumentación de campo como la secuencia constructiva y los tiempos de los ciclos de excavación impactaron altamente el desempeño de la estructura. Los efectos del concreto, dependientes del tiempo y la temperatura que son tratados en esta investigación no son tenidos en cuenta de forma integral en los análisis y durante la etapa de diseño, ignorar estos efectos es la principal razón de las deformaciones laterales resultantes de estas estructuras
James R. Martin - One of the best experts on this subject based on the ideXlab platform.
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Sheet Pile Tensions in Cellular Structures
Journal of Geotechnical and Geoenvironmental Engineering, 2003Co-Authors: Kord J. Wissmann, Reed L. Mosher, George M. Filz, James R. MartinAbstract:Cellular structures constructed of interlocking steel sheet piles are used in marine environments as Cofferdams, bulkheads, mooring dolphins, and lock guide walls. In addition to providing safety against sliding, bearing failure, overturning, and tilting, cellular structures must also be designed to prevent sheet pile interlock rupture, which can lead to catastrophic failure if the cell fill is lost. Methods commonly used to estimate sheet pile interlock tensions were developed in the 1940s, 1950s, and 1970s. These methods are based on empirical observations, and they do not explicitly account for soil–structure interactions. This paper presents the results of finite element analyses and instrumentation measurements performed to examine soilstructure interaction effects on sheet pile tensions. The finite-element analyses were used to compute sheet pile tensions at five instrumented cells, and the results are compared with measurements. The calibrated finite-element model was then used to investigate the effects of varying cell geometry, interlock behavior, sheet pile penetration depth, and foundation stiffness on sheet pile tensions. The instrumentation measurements provide data for estimating changes in sheet pile tensions due to cell fill densification, cofferdam unwatering, and bulkhead backfilling.
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SHEETPILE CELL FILLING: FINITE ELEMENT MODEL VERIFICATION FOR TWO CASE HISTORIES
Transportation Research Record, 1995Co-Authors: Kord J. Wissmann, James R. Martin, George M. FilzAbstract:Cellular sheetpile structures are used as temporary Cofferdams to keep construction activities dry and as permanent bulkheads. Successful design ensures that allowable sheetpile interlock tensions are not exceeded during cell filling operations. For two cellular cofferdam case histories, axisymmetric finite element analyses were performed to estimate main and arc cell fill pressures and arc cell tensions. Results of the analyses are compared with field strain gage data and conventional predictions of main and common wall interlock tensions.
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A study of the effects of differential loadings on Cofferdams
1990Co-Authors: James R. Martin, G. Wayne CloughAbstract:Abstract : Recent studies have suggested that most existing design methods are excessively conservative. This investigation is directed toward providing a data base through the documentation and comparing five case histories where instrumentation was used to monitor the behavior. Primary consideration was given to the response of the Cofferdams under differential loading. In the course of the investigation, the response of each cofferdam was documented and dissected in terms of the behavior at each stage of the differential loading. A strong correlation is found to exist between the lateral cell deflection and the level of differential loading, with the exact nature of the correlation depending on certain key parameters including cell foundation, cell fill material, cell width to height ratio, presence of a stabilizing berm, and nature of loading. It is found for conservatively designed cells that the response falls into a predictable pattern which can be characterized in terms of nondimensionalized parameters for both normal and more severe levels of loading. In addition to deformations, information is provided on interlock tensions where available. The results are believed to provide a baseline for cofferdam behavior that can be useful in gaging the expected behavior of other Cofferdams and for verifying the accuracy of new forms of predictive tools such as the finite element method. (jhd)
B P Williams - One of the best experts on this subject based on the ideXlab platform.
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THE DESIGN AND CONSTRUCTION OF SHEET-PILED Cofferdams
1993Co-Authors: B P Williams, D WaiteAbstract:This report brings together information from many sources, which is likely to be needed for the successful design and construction of steel sheet-piling Cofferdams up to ten metres deep. It recommends considering the use of Cofferdams at the initial project planning stage, so that site investigation can be arranged to provide the information necessary for their design. Other topics covered include: (1) the conceptual design of sheet pile Cofferdams; (2) wall designs; (3) support system designs; (4) the construction, maintenance, and removal of a cofferdam; (5) soil and water pressures on a retaining wall; (6) examples of UK safety regulations; and (7) dimensions and properties of steel sheet piles manufactured in the UK. Worked examples are given for: (1) the design of a sheet pile wall for a cofferdam; (2) the design of an internal frame for a cofferdam; (3) the use of a flow net diagram; and (4) earth pressures for layered ground with non-uniform slopes. The considerable effects of water pressures on cofferdam loadings are emphasised, and various methods of calculating these pressures are given. There are many checklists and comprehensive references to relevant literature.
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the design and construction of sheet piled Cofferdams ciria special publication 95
1993Co-Authors: B P Williams, D WaiteAbstract:This report presents the latest good practice on the planning, design, construction, maintenance, and removal of steel sheet pile Cofferdams as used for the support of temporary excavations. The considerable effect that water pressures have on loading on the cofferdam wall is emphasized.