Surge Load Research Articles

Response Sensitivity for Probabilistic Damage Assessment of Coastal Bridges under Surge and Wave Loading

The susceptibility of coastal bridges to damage during hurricane-induced storm surge has been illustrated along the U.S. Gulf Coast in several hurricane events. This factor poses a significant threat to the safety of nationwide transportation systems, effectiveness of postevent emergency response and recovery activities, and socioeconomic stability further afforded by functioning transportation infrastructure. Nationwide risk and loss assessment packages currently lack any reliable input models of bridge fragility to assess the risk to the transportation infrastructure posed by hurricane-induced storm surge and wave. However, these tools are essential for comparing the vulnerability of different bridge types, conducting regional risk assessment or loss estimates, and supporting decision making on risk mitigation activities. As a first step in the development of probabilistic models of bridge vulnerability subjected to hurricane scenarios, sensitivity studies are conducted to assess the significance of varying hazard and bridge parameters on the dynamic response of coastal bridges. Three-dimensional nonlinear finite element models are used to assess these demands under varying input modeling parameters, and an analysis of variance is conducted to evaluate the significance of each parameter. The sensitivity study reveals that the potential variation in wave parameters has the most statistically significant impact on the response of the bridge. Additionally, a second-level sensitivity study reveals that the most critical structural parameter is the deck mass followed by connection modeling parameters. The results of this study provide insight into modeling parameters that should receive careful treatment in probabilistic analysis of bridge vulnerability.

Wave Impact Study on a Residential Building

Recent natural disasters around the world including both tsunamis and hurricanes, have highlighted the inability of wood buildings to withstand wave and surge loading during these extreme events. Little is known about the interaction between coastal residential light-frame wood buildings and wave and surge loading because often little is left of the buildings. This leaves minimal opportunity for forensic investigations. This paper summarizes the results of a study whose objective was to begin to better understand the interaction between North American style residential structures and wave loading. To do this, one-sixth scale residential building models typical of North American coastal construction, were subjected to tsunami wave bores generated from waves of heights varying from 10 cm to 60 cm. The lateral force produced by the wave bores were, as expected, found to vary nonlinearly with parent wave height.

Integrated Power Converter Design to Meet Uninterruptible Supply and Short Surge Load Demands

This paper generalises the design of AC/DC switching power converters for applications with power factor correction, short surge load and uninterruptible power supply demands. The design focuses on achieving better utilisation of the DC bus voltage, fast transient response and provision of backup power. A number of new designs have been identified. Experimental results of a selected converter topology design are provided to verify the effectiveness of the proposed power supply design concept.

Observations of Structural Damage Caused by Hurricane Katrina on the Mississippi Gulf Coast

The loads associated with Hurricane Katrina led to the destruction or severe damage of approximately 130,000 homes and over 200 deaths in the state of Mississippi. This paper discusses the results of a field inspection of structural damage along the state's Gulf Coast area caused by this hurricane. It was found that reinforced concrete, steel frame, and heavy timber structures generally performed well, with minimal structural damage. Precast concrete, light frame wood, and bridge structures generally performed poorly. Nonstructural components of all building types, in particular facades and interior partitions subjected to storm surge, were typically destroyed. For various structures, the primary cause of failure was found to be insufficient connection strength. A comparison of Katrina's storm surge and wind loads is made to those specified in current design standards. It was found that Katrina's forces exceeded those specified in design standards in many parts of the state.

Utility of ambulatory blood pressure monitoring in children and adolescents

Diagnosis of hypertension is critically dependent on accurate blood pressure measurement. "Accurate" refers to carefully following the guidelines for blood pressure measurement laid out for children and adults to minimize observer and subject errors that commonly occur in clinical blood pressure measurement. Accurate blood pressure measurement is more important in children and adolescents as the misdiagnosis of hypertension may have a life-long adverse impact on insurability and employment. Automated blood pressure measurement offers multiple advantages in achieving high-quality blood pressure determinations by reducing observer errors. The most commonly used form of automated blood pressure measurement is 24-h ambulatory blood pressure measurement (ABPM). Information on ABPM in children has grown exponentially over the last decade. Normative data exists for diagnosis of hypertension in children using ABPM including a novel method for determining normal values with the LMS method. There is further information about the utility of different determinants of 24-h blood pressure such as dipping status, morning surge and blood pressure load. ABPM has been able to detect significant differences in blood pressure in many disease states in children including chronic renal failure, polycystic kidney disease, solitary functioning kidney, and after renal transplantation. Increasingly nonambulatory automated blood pressure determinations have been used in management of hypertension in children. Although nonambulatory automated readings lack information about nocturnal blood pressure or blood pressure during daily activity, studies have suggested that home automated blood pressure measurements are a helpful adjunct to the usual office blood pressure reading.

Optimization of Loads in Piping Systems by the Realistic Calculation Method Applying Fluid-Structure-Interaction (FSI) and Dynamic Friction

To reduce costs and to extend the lifetime of piping systems their design loads due to valve action have to be optimized. To get the best effect the results of the fluiddynamic and structural calculations should be realistic as far as possible. Therefore, the calculation programs were coupled to consider the fluid structure interaction and the effect of dynamic fluid friction was introduced to get realistic results of oscillations due to pressure surges. Detailed modeling of check valve behavior allows minimizing the pressure surge loading by improving the valve function and adapting it to the system behavior. The method was validated at measurements of load cases in power plant piping systems. Results with different load cases show the effectiveness of reducing the fluid forces on piping. Examples are given to prove the reduction of supports.

Development and successful testing of MCP BSCCO-2212 components for a 10 MVAresistive superconducting fault current limiter

The German government funded resistive superconducting fault current limiter project CURL10 is based on bulk material and aims at the development of a three-phase prototype for themedium voltage level (10 kV, 10 MVA). The key element of the project is the development ofsuitable robust superconducting components. On the basis of the well known melt castprocess (MCP) for BSCCO-2212, these are manufactured by cutting superconductingtubes to bifilar coils. At the operation temperature of 65 K a current density of4000 A cm−2 was achieved. In order to protect the superconductor during limitation the component wasequipped with an electrical shunt contacted on its entire length.Single-phase tests with nine of these components in series, corresponding to a protectedload of 1.2 MVA, have been successfully accomplished and are described in detail. Thesetests include different types of short circuits as specified by the utilities within the projectand included lightning surge loads up to 75 kV.