Knowledge Core Collection:https://hdl.handle.net/11681/464712024-03-28T13:57:55Z2024-03-28T13:57:55ZAnalysis of data from instrumentation program, Port Allen LockSherman, Walter C.Trahan, Charles Curtishttps://hdl.handle.net/11681/470202024-03-26T14:29:53Z1968-09-01T00:00:00ZTitle: Analysis of data from instrumentation program, Port Allen Lock
Authors: Sherman, Walter C.; Trahan, Charles Curtis
Abstract: Port Allen Lock is a reinforced concrete U-frame structure located on the west bank of the Mississippi River near Baton Rouge, La. The lock chamber was designed for a trapezoidal distribution of base pressure. This distribution was determined by a trial method in which the plastic and elastic deformation of the base slab and the corresponding deformation of soil foundation were computed for various assumed base pressure distributions until the desired agreement between structure and soil deformations was obtained. The lock chamber was instrumented to obtain engineering data for use in design of similar structures and to determine the validity of the design assumptions. Measurements were made of earth and hydrostatic pressures beneath the base slab and along the walls of the lock and of stresses and strains within the base slab and walls of the lock. The settlement of the lock was determined at various locations, and deflections of the walls were determined by means of wall deflection pipes and a deflectometer. Observed rebounds were greater than those predicted in design: observed settlements were less than those predicted in design. Observed base pressures differed from the total structure load, and the difference was attributed to frictional soil forces acting on the outer sides of the lock. Computations of base pressures and moments from theoretical consideration of a beam on an elastic foundation were in poor agreement with actual base pressures and moments computed from observed loads.
Description: Technical Report1968-09-01T00:00:00ZInvestigation of plane strain shear testing. Report 1, WES high-capacity plane strain shear apparatusAl-Hussaini, Mosaid M.https://hdl.handle.net/11681/216452023-02-15T19:13:09Z1971-03-01T00:00:00ZTitle: Investigation of plane strain shear testing. Report 1, WES high-capacity plane strain shear apparatus
Authors: Al-Hussaini, Mosaid M.
Abstract: Abstract: The stress-strain conditions in many practical problems, such as retaining walls, embankments, and bearing capacity problems, can be approximated by plane strain conditions. In order to gain fundamental understanding of the behavior of soil or to analyze and predict the stresses within such structures, laboratory tests should be conducted under conditions similar to those existing in the field, i.e., plane strain conditions. Thus there is a need for plane strain apparatus that can simulate field conditions; this need formulates the basis of this study. The immediate concern of this study was to review and evaluate plane strain apparatus used by previous investigators and to design and construct a plane strain apparatus that incorporated outstanding features of previous apparatus. The new plane strain apparatus tests soil specimens 16 in. long, 5 in. high, and 2 in. wide under plane strain conditions with complete ability to apply and measure principal stresses. It also enables measurement and control of strains in the directions of principal stresses. With this apparatus the specimen can be consolidated under isotropic or anisotropic stress conditions and can be sheared under drained or undrained conditions with measurement of pore water pressure. Two series of tests on crushed Napa basalt were conducted in the new plane strain apparatus. In the first series, the initial relative density of the specimen was 70 percent, while in the second series, the initial relative density was 100 percent. Each series consisted of two tests: the specimen of the first test was consolidated under Kₒ condition; the specimen of the second test was consolidated isotropically; and both were sheared under drained conditions at a confining pressure of 60 psi. Calibration and demonstration testing indicate the WES high-capacity plane strain shear apparatus to be precise, flexible, and efficient in operation. It is believed to represent a significant addition to the capability of the U. S. Army Corps of Engineers for testing soils under conditions more closely simulating in situ conditions.1971-03-01T00:00:00ZGround shock calculation parameter study. Report 2, Effects of various bottom boundary conditionsBaladi, George Y.https://hdl.handle.net/11681/216442023-02-15T19:05:18Z1972-11-01T00:00:00ZTitle: Ground shock calculation parameter study. Report 2, Effects of various bottom boundary conditions
Authors: Baladi, George Y.
Abstract: Abstract: A parametric study of the effects of rigid, roller, and transmitting bottom boundary conditions on high-explosive airblast-induced superseismic ground shock calculations was conducted using a U. S. Army Engineer Waterways Experiment Station-modified version of the two-dimensional (2D) axisymmetric LAYER code developed by the firm of Paul Weidlinger, Consulting Engineer. The constitutive relation used was a nonlinear, elastic-plastic, hybrid-type model. The constitutive properties used were those of the two-layered soil profile employed in Report 1 of this series. Seven different calculations were performed to study the effects of the depth to the bottom boundary and the differences in ground shock resulting from the use of different types of boundaries at a given depth. Results of this study showed that the transmitting boundary provides an adequate simulation of an elastic medium beyond the calculation domain for a large class of finite difference 2D nuclear ground shock boundary value problems in elastic, inelastic, and layered media under superseismic conditions. Variations in the depth to this boundary within the bottom layer had a very small effect on the results. Use of the transmitting boundary at a shallow depth resulted in a major reduction in computer requirements and calculation cost. The study also showed that both the roller and the rigid bottom boundaries result in significant spallation phenomena and that calculation results using these two boundaries located at shallow depths provide upper and lower bounds to the radial motions calculated using a shallow transmitting boundary or a very deep bottom boundary (i.e. semi-infinite simulation). Two rigid bottom boundary prescriptions (Rigid Bottoms I and II) were investigated. It was shown that there are two differences between the Rigid Bottom I and II calculations : (A.) a difference in depth of a half box, and (B.) an actual difference in the numerical treatment of the same physical condition. However, Rigid Bottom II, which was coded by using an antisymmetry condition, satisfied all the theoretical requirements. Therefore, it should be used in future rigid bottom calculations.1972-11-01T00:00:00ZEarth vibration effects and abatement for military facilities. Report 2, The particle motion field generated by the torsional vibration of a circular footing on sandHeller, Lyman W.https://hdl.handle.net/11681/216432023-02-15T18:26:14Z1972-04-01T00:00:00ZTitle: Earth vibration effects and abatement for military facilities. Report 2, The particle motion field generated by the torsional vibration of a circular footing on sand
Authors: Heller, Lyman W.
Abstract: Abstract: Over the past few years, it has been demonstrated that the self-excited vibratory motion of a circular footing on various types of soil can be successfully predicted by a mathematical model derived by assuming that the foundation soil is represented by a homogeneous elastic half-space. This finding suggested that the same model, or variations thereof, might be useful for predicting the particle motion generated within a soil foundation by a vibrating footing. The objective of this study was to test the hypothesized utility of the half-space model for predicting the motion field generated in a natural soil deposit by the forced torsional vibration of a circular footing. The test involved the computation of half-space motion, the measurement of soil motion, and a comparison of the computations to the measurements. A 5-ft-diam footing was vibrated at 5 different frequencies on a natural sand deposit with a shear modulus that varied from about 1,800 psi at a depth of 1 ft to about 23,000 psi at a depth of 35 ft. Resultant particle motions were measured on the footing and at radial distances to 90 ft and at depths to 35 ft. Homogeneous half-space particle motions were computed using a shear modulus of 9,480 psi. The average measured particle displacement, neglecting damping, was between 1/3 and 1/4 of the computed displacement. The measured displacements were 1/10 of the calculated displacements at the deeper locations and 3 times the calcu1ated displacements near the ground surface. Near the footing, the displacements were in good agreement. Recent literature on the stress conditions in a nonhomogeneous elastic half-space suggested that the particle displacements in a homogeneous half-space could be used to determine the particle displacements in a nonhomogeneous half-space. When the sand deposit was considered as a nonhomogeneous half-space and damping was neglected, the displacements were in good agreement near the footing, the average measured displacement was 60 percent of the computed displacement, and the measured displacements were 1/4 to 2-1/2 times the computed displacements. The material damping effect on the propagating body waves agreed with previous determinations for this effect on surface waves at a similar test site. The correlation between the ratio of the computed displacement to the measured displacement and the cone bearing capacity of the sand deposit at various depths suggested that a more accurate and detailed determination of the shear modulus of the sand would improve the correspondence between measured and computed results. Because the accuracy of the particle displacement predictions was adequate to classify transmitted vibrations as either undetectable, readily apparent, or intolerable, the elastic half-space model, adjusted for nonhomogeneous site conditions, was considered a potentially useful analytical representation of a natural soil deposit subjected to torsional footing vibrations.1972-04-01T00:00:00Z