Static and dynamic behavior of the dry and saturated Ottawa sand are studied in the constitutive modeling laboratory, by using cubical multiaxial device with servo-controlled loading system and high speed automatic data acquisition system. In this investigation, the multiaxial cubical device with servo-controlled loading system and high speed automatic data acquisition system is used to apply independently the three-dimensional loading and measure corresponding strains and stress. The cubical multiaxial device is modified to include the servo-controlled pressure system and automatic data acquisition system. To understand the cyclic behavior and post cyclic behavior, comprehensive laboratory tests have been performed on the dry and saturated Ottawa sand, covering a number of relative densities and confinements.

No description available.

<p>The construction of the consecutive weirs and excavation along the Nakdong River in Korea changed many channel characteristics such as longitudinal slope, cross-sectional area, water stage which led to changes in erosion and sediment transport patterns. It is now necessary to assess the sedimentation problem upstream of the weirs and seek a way to mitigate the problem. </p><p> The study site of Sangju Weir has been selected for this study because it is a representative site for these types of problems and because sufficiency and availability of data. The purpose of this research is to: (1) estimate incoming sediment yield, define the trap efficiency and estimate the reservoir sedimentation rates of weirs and low-head dams using the Flow-Duration and Sediment Rating Curve (FD/SRC) method, along with the Series Expansion of the Modified Einstein Point Procedure (SEMEPP) to determine the long-term sediment yield for Sangju Weir from suspended load concentration measurement; (2) find the B/C ratio and break-even point between hydropower production revenues and sediment excavation costs using a Benefit and Cost Analysis (BCA); (3) suggest new operation rules for Sangju Weir and propose a systematic analysis procedure to find a better operation rules for mitigating sedimentation problems using the Multi- Criterion Decision Analysis (MCDA) method. </p><p> First, in this study, the Integrated Reservoir Sedimentation Estimation Procedure (IRSEP) was proposed to estimate the reservoir sedimentation at weirs and low-head dams. IRSEP integrates all conventional methods related to reservoir sedimentation: (1) Flow-Duration (FD), (2) Sediment-Rating Curve (SRC), (3) Series Expansion of the Modified Einstein Point Procedure (SEMEPP), and (4) Trap efficiency (TE), in order to estimate reservoir sedimentation rate. Steps (3) and (4) constitute the new elements of this type of analysis. Through stream flow runoff modeling and channel geometry analysis, the trap efficiencies in accordance with certain stages were defined. The trap efficiency of Sangju Weir was calculated for each sediment size fraction as a function of the variables, sediment load at daily discharges and particle size distribution of the sediment transported by the Nakdong River. The trap efficiency is also dependent on channel geometry, inflow discharge and reservoir stage determined by the operation rules at Sangju Weir. Then, the amount of reservoir sedimentation was calculated by multiplying the annual sediment load with trap efficiencies, which vary with discharge and water stage. As a result, the reservoir filling rates were examined. Second, the B/C ratio and break-even point between hydropower production revenues and sediment excavation costs were estimated using a Benefit and Cost Analysis (BCA) method based on daily-modeling. It is essential to determine the effects of the reservoir operation rules using the Multi-Criterion Decision Analysis (MCDA) technique in order to seek improvement in the operation rules to mitigate sedimentation costs, simultaneously considering the other decision makers&rsquo; interests. Finally, new operational rules for Sangju Weir and a systematic analysis procedure were proposed. </p><p> The conclusions of this research are summarized as follows: (1) the total incoming sediment load and the average trap efficiency (TE) at the lowest (EL37.2m) and highest (EL47.0m) stages were estimated as 425,000 tons/year, 50.1 % and 78.1%, respectively; and the maximum annual amount of reservoir sedimentation at Sangju Weir was estimated as 332,000 tons/year (207,000 m³/year) which corresponds to 0.76 %/year of the total reservoir storage of Sangju Weir. On the contrary, the minimum reservoir sedimentation rate was 0.49 %/year, which was come when the water stage was the lowest (EL37.2m). (2) Since the operation rules of Sangju Weir affects significantly the trap efficiency, a Benefit and Cost Analysis (BCA) based on daily-modeling was performed in order to find the break-even point between hydropower production revenues and sediment excavation costs. For daily sediment transport modeling, historical and predicted reservoir stream flow data (2015&ndash;2034) were generated by Tank model using seventy-six daily precipitation data. The B/C ratio obtained 20 years of daily simulation was calculated as 2.28. Also, the discharge and stage thresholds, balancing both hydropower production revenues and sediment excavation costs, are found as 600 m3/s and EL43.6m, respectively. (3) based on the daily Multi-Criterion Decision Analysis (MCDA) modeling, the most favorable Sangju Weir operation rules to mitigate reservoir sedimentation were found in Alternative 5 after including seasonal management of stage control according to the magnitude of the upstream inflow. [table omitted]</p><p> The systematic analysis procedure, the combination of the Integrated Reservoir Sedimentation Estimation Procedure (IRSEP) and the Multi-Criterion Decision Analysis (MCDA) method, are deemed useful to find optimum operation rules of weirs and low-head dams, which can mediate the disputes among various decision makers who have different interests related to reservoir operation. The proposed methodology could be applied to the other weirs of the Four River Restoration Project, and elsewhere. (Abstract shortened by ProQuest.)</p>

Entre 1852 y 1860, se importaron a Lima un grupo de veinte esculturas bajo financiamiento del estado peruano, pasando por dos presidencias: se idearon con la de Rufino Echenique (1851-55) y se ejecutaron con la de Ramón Castilla (1855-62). Dieciocho de ellas fueron dispuestas en la Alameda de los Descalzos, una en la Plaza de la Constitución, y otra en la Alameda Nueva (o de Acho). Respectivamente, y en orden de arribo, corresponden dichos emplazamientos a la Serie de los doce meses o Serie del zodíaco (1858-59) más una Serie de seis dioses griegos (1857) en la portada de ingreso; a la Estatua ecuestre de Simón Bolívar (1859); y a la Estatua conmemorativa de Cristóbal Colón (1860). A excepción del Bolívar que fue hecho en bronce, todas eran esculturas de mármol; y su repentina aparición en suelo limeño, supuso un novedoso quiebre con la tradición de innumerables imágenes de madera policromada de las iglesias coloniales. Acostumbrada la población a un arte cuyo acceso dependía en su mayoría de la liturgia, el concepto de lo público cambió de inmediato al invadir, las esculturas, las plazas y paseos de la ciudad. Ya no eran imágenes de devoción, sino de exaltación republicana, y en ellas se debía sintetizar la cotidianidad de la ciudadanía. Es difícil imaginar el grado del impacto generado, pero algo del mismo nos ha llegado hasta estos días, aún a través del desconcierto de personajes perdidos en la historia, aún entre la desconsiderada población de obras mediocres que inundan nuestro imaginario, y aún a pesar de la iconoclastia grafitera. Las esculturas traídas a Lima en la década de 1850 se pierden en el desorden del tiempo, y por sobre ello, siguen guardando celosamente sus espacios privilegiados. Ningún otro lugar de Lima ostenta tantas esculturas juntas como la Alameda de los Descalzos, y su bandalización sólo puede conmover con ese encanto de ruina al que tan cerca se encuentran. Y hasta hace poco, el Colón ostentaba una pinta de tono libertario contra su papel histórico, revelando de ese modo, al ser víctima del desprecio, que se la sigue considerando, todavía hoy, como un símbolo vivo. Pero su gestación y arribo no fueron fáciles, como tampoco es simple desentrañar la riqueza simbólica con la cual se las encargó; y es responsabilidad del historiador del arte poner tales condiciones en realce. Así, la sorprendente pervivencia de las estatuas, a través de dos gobiernos y dos guerras civiles sucesivas (1854-55 y 1856-57), pone en relieve su importancia cultural, dándose que la fuerte insistencia política por el proyecto estatuario se revele como una incógnita, por lo que el problema principal al que se enfrenta el presente trabajo es: ¿qué significó la inversión gubernamental en estatuas públicas para la ciudad de Lima de la década de 1850? Para dar respuesta, el estudio propuesto acá, desde la perspectiva disciplinaria y desde las herramientas metodológicas de la Historia del Arte, abarca el análisis formalista e iconográfico de tales estatuas que se idearon, crearon e importaron entre los dichos años, para finalmente ser colocadas en los distintos puntos públicos de la ciudad de Lima ya mencionados. Asimismo, el estudio demanda una exploración en los aspectos políticoculturales de la época, debido, primero, a que el ente promotor de las estatuas fue el Estado, durante dos gobiernos enfrentados, el de Rufino Echenique y el de Ramón Castilla; y segundo, a que el carácter de las esculturas fue cívico, puesto que estuvieron dirigidas, dentro de un proyecto de consolidación nacional, hacia la exaltación y formación de los valores ciudadanos. Cabe identificar, además, y de manera rápida, que las estatuas hunden sus raíces en el neoclasicismo del siglo XVIII. Los autores son Adamo Tadolini (Simón Bolívar) -1788 a 1868-, discípulo de Canova, y el más joven Salvatore Revelli (Cristóbal Colón) -1816 a 1859-, discípulo de Tenerani quien a su vez lo fue de Thorwaldsen; y para la Alameda de los Descalzos, aparece un abanico de otros artistas en su mayoría ligados a Thorwaldsen. La Serie de seis dioses griegos es anónima pero denota un claro origen neoclásico. El meollo formalista del asunto está, entonces, en el desarrollo de la escultura neoclásica italiana hacia la tendencia del Purismo de las décadas de 1840 hasta la de 1850. Y aparentemente de manera paralela, pero más bien con constantes cruces, el carácter del ideario iconográfico parte del Romanticismo, pues, como se verá, en algunos casos rastrear sus raíces será remontarse de manera directa a la Edad Media, y porque también las estatuas limeñas se establecen siempre como direccionadas hacia la conformación de una identidad nacional. La relación entre el Romanticismo y el desarrollo inmediatamente posterior al Neoclasicismo, es compleja1. Hilda Barentzen (2006) al respecto del gusto neoclásico y el Romanticismo, ha señalado: “[d]os conceptos enlazados al igual que la práctica de sus estilos. Es lugar común referirse al neoclasicismo como un movimiento romántico por las idílicas aspiraciones de cientificismo, orden y mesura que aparentemente lo caracterizaron, pero desde sus orígenes, tanto el gusto neoclásico como el romanticismo parecen fundirse en una extraña relación que Catlin y Grieder califica de paralela. De otra manera, también podemos decir que neoclasicismo y romanticismo son como una serpiente que se muerde la cola y cuyo cuerpo está compuesto por una abigarrada multitud de elementos que lentamente van definiendo su color. En la simultánea persistencia de ambos estilos se explicarían también las controvertidas posturas políticas de ambos períodos” (Barentzen 2006, pp. 77-78). Un texto más concentrado en tal problemática es Honour (1994). Sin embargo, identificadas esquemáticamente las líneas de estudio, uno se encuentra con que un poco más de ciento cincuenta años después de la colocación de las estatuas en suelo limeño, una revisión acerca de su presencia como fenómeno cultural está a la espera. Estudios detallados de sus raíces iconográficas y la justificación temporal de sus aspectos formales, brillan por su ausencia. A lo dicho, se suma la constante reubicación urbana del Colón y los cambios constantes del aspecto de los espacios públicos. Así, la exigencia de imaginar a las estatuas en su espacios primeros, tal cual eran, y teniendo en cuenta que la Alameda Nueva ya desapareció como tal (por lo que incluso las fotografías de la época son una ayuda parcial), genera más incógnitas de las que se han tratado siquiera de resolver.

<p> This thesis presents the construction sequence of a liquefaction tank for simulating liquefaction for observation and laboratory testing. The project consists of constructing an acrylic tank to hold sand, a water reservoir, casting a porous stone to allow even water distribution, installing a pipe system and pump for water flow, manufacturing lateral support braces, and modifying a steel cart to install the whole assembly. </p><p> Sand collected from Junipero Beach within the city of Long Beach is used as the testing media in the tank. Sand collected at this location shows favorable liquefiable gradations and is located within a liquefaction hazard zone. Laboratory testing using the proposed liquefaction tank demonstrated that this apparatus is functional and able to induce liquefaction on the sample of Long Beach sand.</p>

<p> Cofferdams are often employed as temporary watertight structures made of sheet piles and internally braced with steel or reinforced concrete ring beams to retain surrounding soil. For urban cofferdam excavations, soil removal is performed following a bottom-up performance and concrete shear walls and foundations are installed in rock or competent soil. The main goal of this study is to compare the observed performance of two cofferdams projects and conduct a series parametric analysis to study the effects of installation activities of steel ring beams. The first case history is the One Museum Park West (OMPW) and the second is the construction of a cofferdam of a structure projected to be the tallest building in America and the deepest basement built in the city. These two cofferdams evidence the need of a strict deformation control plan applicable to every construction stage, including those considered as ancillary.</p>

Potentially high risk medical procedures are performed in hospital operating rooms (ORs) across the country on a daily basis. There are detailed and stringent procedures in place for routine practices, such as handwashing and instrument sterilization, and for the HVAC (heating, ventilation and air conditioning) systems, such as controlling humidity and ventilation rates. To maintain the sterile conditions, ventilation rates, measured in air changes per hour (ACH), are understandably higher than any other hospital space. While the highest air change rates may be required to provide a quality indoor environment to minimize the risk of surgical site infections (SSIs), there are significant capital and operating costs associated with these requirements. The ventilation requirements for ORs have increased over the past 10 years with minimal data to support that more air provides cleaner conditions. We hypothesized that a test of the air quality utilizing dynamic, surgical procedures would provide evidence showing increased ventilation does not necessarily provide cleaner conditions. The costs were estimated based on actual energy usage, while the air quality metrics were Environmental Quality Indicators (EQIs). This enabled a comparative analysis of the costs and benefits of different air change rates in an operating room to assist in defining the optimum air change rates. To compare the air quality in ORs under realistic conditions, a testing protocol using EQIs was developed and implemented by an interdisciplinary team, including medical clinicians, air quality experts and engineers experienced in ORs. The testing included a âmockâ surgical procedure directed by a Board certified surgeon in three actual operating rooms using standard gowning and sterilization practices with experienced staff to simulate actual conditions. The results showed that the air quality was significantly better at 20 ACH than at 15 ACH, but did not significantly improve at 25 ACH. The additional operating costs for 5 ACH at the typical facilities tested was approximately $4000 per year per operating room. For academic medical centers and hospital systems with many ORs, this could be significant savings, but the cost must be weighed against the risk of potentially increasing surgical site infections (SSIs).

<p> Reliability based analysis is a well-established tool in probability-based structural design. The load equation from the ACI Code along with several others ACI design methods are analyzed in order to verify that the reliability index using limit state functions are consistent across both determinate and indeterminate beams. This research provides an in-depth analysis and comparison of reliability indices for types of structures. Literature review describes the different probabilistic models used in the analysis. Several different probabilistic models are used in order to determine the reliability index of determinate and indeterminate structures. Standard reliability methods, such as the first-order reliability method (FORM), modified Rackwitz-Fiessler method, and Monte Carlo Simulations, are used in order to evaluate the reliability index of determinate beams and indeterminate beams designed with moment redistribution. </p><p> The research also presents the methodology and results of the reliability index of structures using different analysis methods. Reliability analysis methods are used to verify the safety of structures under different loading conditions for both determinate and indeterminate structures. The key outcomes of the research outlined in this Master&rsquo;s thesis are the following: </p><p> 1) Reliability index a. Closed-form solution is independent of the structure type b. Remains consistent across range of live load to dead load ratios 2) Reliability index did not vary greatly, regardless of: a. Structure b. Loading type c. Moment redistribution 3) The closed-form solution is more conservative and results in a lower reliability index. The refined method using the ACI design results in a higher reliability index.</p>

<p> This dissertation attempts to develop simple and direct approaches to estimate the vehicle queue length and travel time along signalized arterial links for real-time traffic operations. This dissertation is the first to demonstrate a process using vehicle trajectory data to generate detector volume, speed and time occupancy data, along with the generalized flow rate, density and space mean speed data. This approach minimizes detector over-counting and miss-counting issues. The detection zone can be of any shape or size and at any location along the trajectory. The relationships among detector volume, speed and time occupancy along signalized arterials are analyzed theoretically and experientially. If the generalized definitions of flow rate, density and space mean speed are used, the fundamental relationship, <i>v</i> = <i>ds</i>, holds valid in a signalized arterial environment. The fundamental relationship diagram plotted using field signalized arterial data has not been seen in any of the literatures reviewed.</p><p> Within the defined time-space region, the scatter diagram of the generalized density and the detector time occupancy presents a strong linear correlation. Simply converting detector volume counts within one data collection time period to use as the generalized flow rate introduces estimation errors. There are two major reasons. The first is that vehicles don&rsquo;t completely cross the detector during the data collection time period. The second is that it assumes vehicles would evenly spread across the data collection time period when crossing the detection zone. Traffic flow intensity is introduced and defined within the time-space regions to provide much more accurate description of the traffic flow arrival and departure conditions.</p><p> This dissertation attempts to make improvements to the input-output technique for queue estimation along signalized links. Based on analyses of the theoretical and experiential cumulative input-output diagrams, also known as the Newell Curves, two major improvements are proposed to improve the performance of the input-output technique. The improvements take into account vehicles stop on top of detectors in the estimation, make necessary adjustments to detector vehicle counts, and introduce a reset mechanism to remove the accumulated estimation errors during a long time period. The improvements are tested using two sets of field data. One set of data are 10-second queue and virtual detector data generated using the Federal Highway Administration Next Generation Simulation Peachtree Street dataset. The other set of data are field manually collected 20-second queue, and loop detector vehicle count and time occupancy data at metered on-ramps. It is concluded that both improvements help to produce estimation results far better than the original input-output technique. With adjusted detector vehicle counts, the performance of the Kalman Filter queue estimation model is also improved.</p><p> A simple conservation law approach is developed to estimate travel time along signalized arterial links. Inputs used include the traffic flow intensity at input and out detectors, plus the initial vehicle queue. The estimated travel time is tested with the field travel time data to evaluate the performance of the estimation. The developed model is also compared with the NCHRP Project 3-79 model and the Little&rsquo;s Law queueing theory model. The developed model performs much better for per short interval travel time estimation. </p><p> The proposed travel time estimation approach only uses the detector volume and time occupancy data. It does not rely on signal timing data to estimate the control delay or a delay model to estimate the queueing delay. In addition, neither roadway geometry nor vehicle length data are used.</p>

<p> The objective of this study is to create and evaluate if finite element modeling is a feasible approach to modeling different wedge geometries of post tensioned systems by comparing the experimental data from two wedges to analytical data. The motivation to develop an accurate finite element model of a wedge, tendon, and anchor system is to better understand the internal stresses the system is subjugated to and the interactions between components. By not fully understanding what is occurring within the anchor, the most efficient anchor cannot be designed. This can lead to premature failures of the strand which can result in total collapse of the structure. In recent years the applications of post tensioned strands have grown rapidly. Some of these applications require the strand to withstand higher strains than can currently be reached. An example of one of these applications is a shear rocking wall in earthquake prone areas. To date there is some experimental data on strand testing, but very little research has been conducted examining a modified geometry wedge. There is even less in depth literature on finite element modeling of the interactions between the components. One reason for this lack of research is because of the great variability in anchor and wedge configurations. Therefore, the focus of this research is to develop the interaction laws for one type of anchorage from one manufacturer. Once these laws are established and considered scientifically sound, the most efficient anchor wedge mechanism can be designed. </p><p> This thesis presents one of the stepping stone models needed to help converge on the interaction laws. The experimental component of this report evaluated two different wedge geometries. In the experimental trials the modified wedges preformed more efficiently than the standard wedges. The modified wedges were able to reach much higher strains. These geometries were modeled in a finite element program and the experimental results were replicated by adjusting the interaction relationships. The starting point for the relationships were based off of the studies found in the literature review. The results from analytical model of the standard wedges matched the experimental results very accurately. The analytical model of the modified wedge requires refinement. The results of the analytical model did not match the experimental observations as well as they should. However, the results still support the theory that the computer software can differentiate between standard and modified wedge geometries.</p>