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The seismic performance of port structures has been well documented following recent earthquakes, and indicates that port structures are highly susceptible to earthquake-induced damages. These damages are primarily due to soil liquefaction and the associated ground failures. Sheet pile bulkheads provide vital intermodal and lifeline transportation links between water-side and land-side traffic, and are waterfront structures particularly vulnerable to liquefaction-induced damages. Due to the prevalence of liquefaction-induced damages, many ports are utilizing soil improvement techniques to mitigate these hazards. Many port authorities have proposed utilizing performance-based design criteria to limit potential earthquake-induced damages. The current design method for sheet pile walls (Mononobe-Okabe) is based on simple, limit equilibrium analysis techniques, which are poorly suited for performance-based design. Recent advancements in the seismic design of sheet pile walls have addressed some of the limitations of the current design methods, but are still inadequate for performing a complete, performance-based design for locations that contain potentially liquefiable soils and/or where soil improvement strategies have been instituted. This study has focused on conducting an empirical investigation and numerical modeling to determine the seismic performance of sheet pile walls, and the performancebased benefit of soil improvement through densification. A case history validated, nonlinear effective stress computer program was used to perform numerical parametric studies on various design parameters (earthquake properties, depth of sheet pile embedment, sheet pile wall stiffness, tie rod length, density of the backfill, and extent of soil densification). The results have been presented as a performance-based design method, and include a design chart that provides practitioners with a preliminary design tool that may be used to estimate the seismic deformations of sheet pile walls with or without soil improvement. The study has demonstrated that soil densification can greatly reduce the seismicallyinduced deformations, especially when the magnitude of soil improvement extends beyond the location of the anchor. The study has also demonstrated that the use of soil densification techniques for mitigating seismic hazards may not be adequate in limiting deformations to allowable limits, and that other methods of soil improvement (cementation, drainage, etc.) or structural improvements may also be required. / Graduation date: 1998

A series of lateral load tests were conducted on assemblies of four, 4 foot long U.S. Steel PS32 (regular strength) and PSX32 (high strength) straight web sheet pile sections. The instrumentation adopted in the testing program was geared toward monitoring the assembly displacements, load transfer characteristics, and interlock response. Average effective E-ratios over three different pressure ranges were computed, interlock force versus pressure relationships were derived, the stress states in the pile webs were examined, and interlock force versus interlock displacement trends were obtained from the resulting data. A total of 12 assemblies were tested, 6 each of the PS32 and PSX32 types. Three tests from each lot of 6 incorporated pretensioning of the assembly prior to application of the lateral pressure; whereas, the remaining tests initiated lateral loading of the assemblies while they were in a slacked state. The results from the tests were generally grouped according to assembly designation (PS32 or PSX32) and type of test (pretensioning or no pretensioning). The tabulation of E-ratios and pile web stresses, and interlock force versus pressure plots revealed consistent relationships among tests in a particular grouping over the 0-30 psi loading range. Interlock force versus interlock displacement trends were physically correct, but provided no conclusive information regarding the response at an interlock connection. / M.S.

Hot-rolled sheet piling has long-been believed to have a better flexural performance than cold-formed sheet piling based on a test conducted by Hartman Engineering twenty years ago. However, cold-formed steel can have similar strength to the hot-rolled steel This experimental program studied the flexural behavior of hot-rolled and cold-formed steel sheet pilings. This program quantified the influence of transverse stresses from soil pressures on the longitudinal flexural strength. Four cross-sections with two pairs of equivalent sectional modulus were investigated. Sheet-piling specimens were subjected to simulated soil pressure from an air bladder loaded transversely to their longitudinal axis. The span lengths were varied, while the loading area remains unchanged to examine the effect of different transverse stresses. Lateral bracings were provided at discrete locations to establish a sheet piling wall behavior and allow the development of transverse stresses. Load-pressure, load-deflection, load-strain, and moment-deflection responses were plotted to demonstrate the behavior of each specimen. The moment-deflection curves were then normalized to the corresponding yield stress from tensile coupon tests to make a meaningful comparison. The results indicate that transverse stresses influence the flexural capacity of the sheet pilings. The longer span length has less amount of transverse strains, resulting in a higher moment capacity. The hot-rolled sheet pilings have better flexural performance also because of less transverse strains. / Master of Science / Sheet piling wall is an essential structure used during the excavation process. Sheet piling can be hot-rolled and cold-formed. Hot-rolled sheet piling has long-been believed to have a better bending performance based on a test conducted by Hartman Engineering twenty years ago. However, cold-formed steel can have similar strength to hot-rolled steel. This experimental program studied the bending behavior of hot-rolled and cold-formed steel sheet pilings. This program quantified the influence of lateral loading from soil pressure on the moment capacity of the sheet piling. Four cross-sections with two pairs of equivalent bending properties were investigated. Sheet-piling specimens were set up as beam members and subjected to simulated soil pressure from an air bladder. The span lengths of the specimens were varied, while the loading area remains unchanged to examine the effect of different amounts of load. Lateral bracings were provided at discrete locations to establish a sheet piling wall behavior and allow local deflection of the cross-section. Load-pressure, load-deflection, load-strain, and moment-deflection responses were plotted to demonstrate the behavior of each specimen. The moment-deflection curves were then normalized to the corresponding material property of each specimen to make a meaningful comparison between different specimens. The results indicate that lateral loading of the soil pressure influences the bending capacity of the sheet pilings. The longer span length has less amount of transverse strains, resulting in a higher bending capacity. The hot-rolled sheet pilings have better bending performance also because of less transverse strains.

The classical use of 0.3 for the static coefficient of friction for sheet pile interlocks was investigated in this study. The effects of cyclic displacements on the coefficient of friction of the interlocks was also examined. A broad range of values for the coefficient of friction was observed for over 2000 observations of the shear force required to initiate interlock displacement. The mean observed value of the coefficient of friction was greater than 0.3 for low interlock stress. The mean coefficient of friction decreased with increased interlock stress. At interlock loads of five kips per inch the mean coefficient of friction was approximately equal to 0.3. The relationship between interlock stress and the coefficient of friction was found to be nonlinear. An exponential model to predict the coefficient of friction for interlock loads between 1 and 5 kips per inch was developed. To study the effects of cyclic displacements on interlock friction the specimen interlocks were displaced approximately one hundred times. No significant effect on interlock friction was observed. / M.S.

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 filling process where the main cell is filled first with the subsequent filling of the arc cell. The finite element results show that interlock forces in the common wall were 29 to 35 percent higher than those in the main cell which are less than those calculated by conventional methods and compare well with the observed values. After cell filling, the new code was used to model the cofferdam under differential loading due to initial dewatering of the interior of the cofferdam and changes in river levels. The finite element analysis results show that increasing differential water loads cause the confining stresses in the cell fill to increase which results in a decrease in the level of mobilized shear strength in the cell fill. This explains why the cellular cofferdam can withstand extremely high lateral loads and lateral deformations without collapsing. / Ph. D.

A finite element program is developed to depict the behavior of a sheet pile interlock connection in an axial pull test. Two types of sheet piles, PS32 and PSX32, are considered. The thumb and finger in the interlock of a sheet pile will provide three contact points for connection with another sheet pile. The problem is highly nonlinear in nature which involves large deflections and rotations, elastic-plastic material response, and a nonlinear boundary effect due to multi-contact surfaces. The Updated Lagrangian formulation is adopted in this study. When the response is in elastic range the Updated Lagrangian with Transformation is used while the Updated Lagrangian with Jaumann stress rate is employed when the element starts to yield. An elastic-plastic with isotropic strain hardening material model is used. The yielding of an element is detected by the Von Mises yield criterion. The finite element formulation also includes a moving contact algorithm to incorporate with both geometric and material nonlinearities. Incremental potential of contact forces for a discretized system is constructed such that geometric compatibilities are maintained between contacting bodies. A method to calculate contact tractions from residual load of internal element stresses is employed. The incremental equilibrium equation is solved by a Newton-Raphson technique. Convergence criteria based on incremental displacement, incremental internal energy of the system, and the changes in contact forces can be chosen to advance or terminate the iteration process. / Ph. D.

A nonlinear movmg contact algorithm has been implemented to model the sticking-sliding inelastic behavior in the interlocks of steel sheet pile sections subjected to axial tension. Previously, numerical instabilities were encountered during the solution process while conducting a series of verification problems for the algorithm by the Newton-Raphson method. In an attempt to identify the cause of these instabilities, an in-depth study of the effect of fineness of the finite element mesh on the convergence of the solution has been undertaken. The solution process credited to Riks and Wempner has been used to find the postbuckling equilibrium path of shallow reticulated domes. This algorithm, with some modifications, is used to move from one load step to another step in this study. As in most nonlinear problems, the size of the load step influences the rate of convergence. In addition, in the moving contact problem nodes can move along the sides of an element on the contact surface. Thus, the mesh refinement also affects the rate of convergence. To study the effects of both of these parameters, a series of test problems was run with variable load steps and mesh refinements. The modified Riks-Wempner algorithm, which automatically adjusts the load step size as the solution process advances, successfully solved all the inelastic and large displacement problems attempted. From the mesh refinement studies two conclusions were reached: for curved boundaries use curved elements and avoid the use of irregularly shaped elements. Finally, the improved solution algorithm is applied fo sheet pile interlocks loaded in axial tension. Results for progressively increasing load show the spread of yielding in the thumbs and fingers of the interlocks and the sliding of one past another as the deformations increase. / Master of Science

The main purpose of this thesis is to describe in detail the processes of selected parts of the construction technology project for the construction of the department store Galéria Lučenec, based on the project documentation provided by the principal engineer. It is a large-scale new building with a cast-in-place reinforced concrete load-bearing structure with steel elements located in the center of Lučenec. The diploma thesis consists of the main parts such as the technical report of the construction technology project, a detailed coordination situation of the construction site, and a detailed time and financial plan of individual buildings. Within the main building, a study of the main technological stages of construction, elaboration of the project site equipment together with the associated design documentation and the technical report, design of the main construction machines and mechanisms, time schedule of the main building processes, and an item budget are described. Within the technological regulation and the control plan, the diploma thesis is focused on the cast-in-place structures of the superstructure. In the final part of the project, there are chapters devoted to topics such as occupational health and safety on the construction site, evaluation of LEED 2009 certification, the procedure for securing the construction pit, and the assessment of the main vertical lifting mechanisms.