Computer program to determine roots of polynomials by ratio of successive derivatives

High speed computing finds roots of polynomials with real number coefficients. Ratios of successive polynomial derivatives approach provides accurate roots-of-polynomial computer programs with very high reliability. With derivative ratio method, root analysis can still be done even though the polynomial and its lower order derivatives cannot be evaluated with sufficient accuracy

Soil-structure interaction during the San Fernando earthquake

Accelerograms obtained at two sites during the San Fernando earthquake of 1971 were analyzed to investigate the role of soil-structure interaction, using techniques developed by Bielak and others. Analysis of the data from the site of the Hollywood Storage Building, for which data from the Arvin-Tehachapi earthquake of 1952 are also available, showed evidence of soil-structure interaction in the way the transfer functions between parking lot and basement motion decayed with increasing frequency in the two lateral directions. It is concluded also that interaction probably had a small effect on the response near the EW fundamental frequency during the San Fernando earthquake. Although theoretical and experimentally determined transfer functions are broadly similar, they do not agree in detail. The lack of good agreement for reasonable choices of the parameters of the theoretical model indicates a need for some modifications of the theory or its application, and a need for more measurements at the site. A similar analysis showed no clear evidence of soil-structure interaction for the Millikan Library and Athanaeum buildings on the campus of the California Institute of Technology. If soil-structure interaction caused the major differences measured in the base motions of these two buildings, it is of a more complex form than that considered by present theories

Centrifuge liquefaction tests in a laminar box

The difficulties associated with instrumenting earthquake sites in order to record pore pressure changes in a future event led to the use of scaled model tests performed in a centrifuge. Both dry and saturated sands were employed, contained in a box constructed of aluminium laminae designed to move freely on each other. This would result in shearing distortions developing in the soil unimpeded by the container. Accelerometers, displacement transducers and pore pressure sensors were attached to the box and embedded in the soil at various elevations so as to record the response of the soil to an earthquake-like excitation supplied to the base of the container. A special apparatus was constructed to imitate earthquake motion. In some tests on saturated sand, the soil profile was liquefied. Test results of accelerations, lateral and vertical displacements and pore pressures against time for typical earthquake inputs are given. The data, obtained under controlled conditions, can be compared with the various calculation methods for dynamically generated pore pressures

Factors Associated with Tenderness of Three Beef Muscles

Tenderness is the prominent quality determinant and probably the most important sensory characteristic of beef steak and roast meat. Currently postmortem aging (storage of carcass at refrigerated temperatures for 8 to 14 days) appears to be the best method for producing tender meat. Although the improvement in meat tenderness as a result of postmortem aging is measurable both subjectively and objectively, the exact mechanism responsible for this improvement in tenderness is unknown. It is well known that different muscles within the same carcass react differently to postmortem storage; for example, tenderloin is tender to begin with and does not improve significantly with postmortem storage, while ribeye is the toughest muscle initially and improves greatly with postmortem storage. The purpose of these experiments was to attempt to answer the following questions: 1)Why are some muscles (e.g., tenderloin) tender at 24 hr postmortem and nonresponsive to postmortem aging? and 2) Why do some muscles (e.g., ribeye and tenderloin) respond differently to postmortem aging

Factors Associated with Tenderness of Three Beef Muscles

Tenderness is the prominent quality determinant and probably the most important sensory characteristic of beef steak and roast meat. Currently postmortem aging (storage of carcass at refrigerated temperatures for 8 to 14 days) appears to be the best method for producing tender meat. Although the improvement in meat tenderness as a result of postmortem aging is measurable both subjectively and objectively, the exact mechanism responsible for this improvement in tenderness is unknown. It is well known that different muscles within the same carcass react differently to postmortem storage; for example, tenderloin is tender to begin with and does not improve significantly with postmortem storage, while ribeye is the toughest muscle initially and improves greatly with postmortem storage. The purpose of these experiments was to attempt to answer the following questions: 1)Why are some muscles (e.g., tenderloin) tender at 24 hr postmortem and nonresponsive to postmortem aging? and 2) Why do some muscles (e.g., ribeye and tenderloin) respond differently to postmortem aging

Vibration Analysis of Rotating Fans Mounted on Adjacent Rectangular Foundation Blocks

Vibration analysis was conducted for large rotating fans mounted on adjacent rectangular concrete foundation blocks, 66 ft x 22 ft x 10 ft depth, with the adjacent long sides 10 ft apart. The blocks were embedded in medium dense sands and gravels with a variable shear-wave velocity profile. The purpose of the analysis was to determine whether (1) the dynamic interaction of the blocks through the surrounding soil would cause unacceptable vibratory response of the fans, and (2) the foundation stiffness criterion set by the vendor was satisfied. Solutions were obtained using the 3-D dynamic version of the FLAC computer program, which was first used to compute the response of a single block-fan system. The introduction of the second block-fan system into the model resulted in less than 10% amplification in dynamic response of the two-block system relative to the single block-fan response, when the excitation forces of both fans were in phase (i.e. 0° lag). However, a maximum amplification of 100% was computed when the phase-angle difference in forces was between approximately 90° and 120°. The results ultimately demonstrated that the vibration and foundation stiffness criteria could be met, which would have been more difficult without the use of a 3-D numerical modeling code

Engineering studies of the San Fernando earthquake

A number of accelerograms obtained during the San Fernando earthquake were analyzed to investigate the nature of the strong motion. The particular features studied were soil-structure interaction and the relative influence of local site conditions versus the source mechanism and travel paths of earthquake waves. Evidence of soil-structure interaction in the EW fundamental mode of the Hollywood Storage building is seen in the earthquake data. General agreement exists up to - 5 c.p.s. in both lateral directions between theoretical, base to free field transfer functions and transfer functions derived from accelerograms obtained in the basement and adjacent parking lot. There was no evidence of soil-structure interaction in the Millikan Library and Athenaeum buildings on the Caltech campus, and this effect could not account for the major differences in their accelerograms. Accelerogram, Fourier Amplitude Spectra, and Response Spectra data were compared from a group of six tall buildings close together near Wilshire Blvd. and Normandie Ave. in Los Angeles and from seven surrounding buildings, two to three miles away. The data indicated that local site conditions and soll-structure interaction were not major contributors to the observed differences in the response at these sites. There was correlation between the degree of similarity in the response at two sites and their distance apart. A simple wave superposition model with numerical examples confirms this correlation

Model Identification and Seismic Analysis of Meloland Road Overcrossing

This report presents the results of research directed toward model identification and seismic analysis of the MRO. This research has been implemented to meet the requirements of Tasks 4 and 5 of the UNR-D&M research program (Sec. 1.1.3) and also to provide a basis for developing improved bridge modeling procedures as required under the D & M research program on SBOs (Sec. 1.1.4). The scope of this research effort consisted of our development of a finite element model of the MRO whose parameters were estimated through the application of state-of-the-art system identification methods to the MRO's recorded motions from the Imperial Valley Earthquake. These estimated model parameters were also checked for consistency with an overall range of model parameter values computed using established engineering procedures. This model was then used in a series of parametric dynamic analyses of the seismic response of the MRO which enabled us to evaluate the effects of uncertainties in the various model parameters on the demand forces and moments in the structural members and the foundation springs. Maximum foundation spring forces and moments obtained from these analyses were used as input to nonlinear static analyses of the MRO's pile foundations in order to compute the demand forces and moments within the piles. The demand forces and moments within the MRO's structural and pile elements were then compared against the capacities of these elements. These analysis results have been interpreted to assess the seismic performance and design of the MRO, and also to provide an important basis for our development of improved modeling and seismic evaluation procedures for short bridge overcrossing structures. The above efforts have focused on the modeling and analysis of the MRO's translational and rotational response to transverse horizontal input motions; i.e., the bridge's response to vertical and longitudinal input motions was not included in this research. This focus on the MRO's response to transverse horizontal input motions was adopted because: (a) this response will lead to more severe earthquake-induced internal forces and moments, particularly in the central pier which is the element of an SBO that is typically most vulnerable to seismic excitation; and (b) our past evaluations of the MRO's recorded motions have shown that its response to transverse horizontal input motions is strongly affected by SSI, whereas SSI has only a negligible effect of the MRO's response to vertical and longitudinal input motions (Werner, et. al., 1987)