Journal of Waterway, Port, Coastal, and Ocean Engineering

This paper describes a reliability based formulation to determine earthquake LRFD parameters for conventional, steel, pile supported, tubular member platforms that is proposed as a basis for earthquake design criteria and guidelines for offshore platforms and that is intended to have worldwide applicability. The formulation is illustrated with application to platforms located in five areas: offshore California, Venezuela (Rio Caribe), the East Coast of Canada, the Caspian Sea (Azeri), and the Norwegian sector of the North Sea. The approach and proposed quantifications have been verified with site specific results from four locations. Good agreements have been developed between the site specific results and those based on these guidelines. The approach provides an important element of information sensitivity that allows the loading and resistance factors to be varied as a function of the desired reliability for a platform, the unique aspects of its seismic environment, and the primary uncertainties in the earthquake loadings and platform element capacities.

The development of a commercial port to its optimum capacity with minimum capital costs is basically contingent upon the efficient loading/unloading of ships. This function is dependent primarily on the number of berths in the port available to ship traffic and the cargo handling capacity. A port must be planned to satisfy prompt accommodation of ships with minimum waiting time in the port and with maximum use of berth facilities. This paper discusses the anchorage-ship-berth link at the river port utilizing queuing theory with bulk arrival. A general model of the terminal is developed. The process is described by the nonstationary, multichannel queuing system. This system has the following characteristics: waiting areas are finite and given, unit bulk arrival into the system is assumed, and arriving ships or barge tows are not allowed into the system if k > (n + m) − s, where k is the number of ships or barge tows arriving at the same time (bulk arrival). All of the main characteristics of the system are given.

To evaluate ex situ contaminated sediment remediation alternatives, an equation or algorithm for estimating the costs of environmental dredging is required. Simple estimators exist in which the total dredging cost is based on the volume of material dredged. Unfortunately, these empirical estimators cannot accurately predict the cost of an environmental dredging project where production rates are slower than normal. An equation was developed for estimating the costs of hydraulic dredging that contains variables to accommodate the lower production rate of environmental dredging and empirical cost coefficients that were derived from the actual costs of 18 navigational dredging projects in the U.S. and Canadian Great Lakes. A similar equation was developed for mechanical dredging based on 20 Great Lakes dredging projects. The sensitivity of the total dredging cost predicted by these equations with respect to the input parameters was determined. The cost predictions of these equations compared favorably with those of the simple empirical estimators for navigational dredging projects.

This paper presents a combined experimental and numerical effort to study solitary wave runup and rundown on beaches. Both nonbreaking and breaking solitary waves are investigated. A two-dimensional numerical model that solves both mean flow and turbulence is employed in this study. For the nonbreaking solitary wave on a steep slope, numerical results of the present model are verified by experimental data and numerical results obtained from the boundary integral equation method model, in terms of both velocity distribution and free surface profiles. The characteristics of flow patterns during runup and rundown phases are discussed. The vertical variations of the horizontal velocity component are large at some instances, implying that the shallow water approximation may be inaccurate even for the nonbreaking wave runup and rundown. For the breaking solitary wave on a mild slope, numerical results of the present model are compared with experimental data for free surface displacements. The present model is found to be more accurate than the depth-averaged equations models. Using this numerical model, the mean velocity field and turbulence distribution under the breaking wave are discussed.

A model has been developed and successfully applied to analyze a network of tidal ponds connected by culverts and bridges. Measured tidal fluctuations under normal and spring tide conditions at the seaward terminus of the tidal ponds were applied as boundary conditions. The model uses the secant modification of the Newton-Raphson method for solving a set of nonlinear differential equations. It was necessary to develop special conduit file generation and interpolation techniques to render the model feasible in terms of required computational time. The model adequately represented tidal fluctuations measured in the tidal ponds under existing conditions. The model was then applied to predict changes in tidal fluctuations resulting from replacement of one of the culverts with alternative bridge designs with and without freshwater runoff. The predictions enabled separate assessment of impacts on shore-side properties with individual septic systems and on water quality, flora, and fauna within the tidal ponds.

Analysis of a network of tidal ponds connected by hydraulically complex conduits requires special conduit file generation and interpolation techniques. Hydraulically complex in this context means that computer-intensive calculations are required to adequately determine flow through each connecting conduit for each combination of headwater and tailwater elevations (e.g., for unsubmerged culverts). Such file generation and interpolation techniques were developed for a specific application that enabled the successful analysis of a network of tidal ponds connected by culverts and bridges. The techniques decreased computational times of an otherwise optimized program by orders of magnitude. Without such techniques, such modeling would not be feasible in terms of required computational time. The computer run times (Pentium-133) of the final model runs ranged from about 10 h or 8.8 times real time to about 3 days or 0.67 times real time, depending on the tide conditions considered and the hydraulic complexity of the interconnecting conduits. The techniques are general and have application to other similar problems.