Michael J. Briggs

Probability assessment for deep-draft navigation channel design

This paper describes a method for assessing the probability of a ship accident in an entrance channel for different recurrence intervals using model data. This new method includes a rational criteria for evaluating various channel configurations and depths for a range of realistic environmental (i.e., wind, wave, and current) conditions and annual number of ship calls. This four-component climatology-interactive model includes a Poisson probability law for number of ship arrivals, a Bernoulli probability law for grounding in a single random ship arrival, an estimation of the probability parameter in the Bernoulli law from model tests, and a determination of recurrence intervals or return periods. A remote-controlled model of a C9 containership was used to evaluate the navigability of existing and proposed harbor and entrance-channel configurations for a range of environmental conditions in a three-dimensional physical model of Barbers Point Harbor, Oahu, HI.

RISK-BASED PREDICTIONS FOR SHIP UNDERKEEL CLEARANCE

This paper describes two new risk-based models for predicting ship underkeel clearance (UKC) in deep-draft entrance channels. In the first model, recurrence intervals are estimated for the number of years between accidents or groundings using Poison and Bernouilli probability distributions for ship arrivals and groundings. The second model predicts channel accessibility based on an acceptable level of risk for different wave, ship, and channel combinations by modeling the uncertainty in these parameters using Gaussian and Rayleigh distributions. Comparisons between both methods are presented

RUNUP OF TSUNAMIS WITH TRANSIENT WAVE PROFILES INCIDENT ON A CONICAL ISLAND

Based on the linear long wave theory, analytical solutions are obtained for the propagation of tsunamis with an arbitrary incident wave profile around a conical island. The validity of the theory is verified through comparisons with two laboratory datasets. Effects of incident wave profile on the distribution of runup height and on the maximum runup height along the coastline of an island axe discussed on the basis of this theory.

RESONANT FORCING OF HARBORS BY INFRAGRAVITY WAVES

A special reflecting wall 12 m long and 2.1 m high was built off the beach at Reggio Calabria, and 30 wave gauges were assembled before the wall and were connected to an electronic station on land. It was possible to observe the reflection of wind waves generated by a very stable wind over a fetch of 10 Km. The experiment aimed to verify the general closed solution for the wave group mechanics (Boccotti, 1988, 1989), for the special case of the wave reflection.Significant features on Wadden Sea wave climate are evaluated in respect of the state of the art. Main emphasis was laid on an analysis of the governing boundary conditions of local wave climate in island sheltered Wadden Sea areas with extensions being sufficient for local wind wave growth. Explanatory for significant wave heights a reliable parametrization of local wave climate has been evaluated by using generally available data of water level and wind measurements.

THE EFFECT OF WAVE DIRECTIONALITY ON NEARSHORE WAVES

Tanah Lot Temple is situated in Tabanan Regency - Bali, on the coast of the Indonesian Ocean. Due to continuous wave attack, wind force, and weathering of the rock bank where the Temple stands, abrasion has occured which is more and more threatening the existence of the Temple. Considering that Tanah Lot Temple is a sacred place for the Hindu Balinese people and a place of high cultural value, and also an important tourism, steps to save the Temple are imperative. The Central as well as the Regional Authorities, and also the Bali nese community are very much interested in the effort to keep the Temple intact. Measures have been undertaken to protect both the seaside and land-side banks of the Temple rock bank. This paper only discusses counter measures of the sea —side bank of the Temple.

PROBABILISTIC MODEL FOR PREDICTING SHIP UNDERKEEL CLEARANCE: FIELD AND LABORATORY VALIDATION

This paper presents validation comparisons between field and laboratory measurements and a new probabilistic model for predicting ship underkeel clearance (UKC). Prototype ship motions and environmental data were obtained in May 1999 in the deep-draft entrance channel at Barbers Point, HI. These field measurements were reproduced in controlled laboratory studies in 2000 and 2002 with a model of the World Utility (WU) bulk carrier. These measurements constitute some of the data being used to validate the Corpss Channel Analysis and Design Evaluation Tool (CADET), a suite of programs to determine the optimum dredge depth for entrance channels. In general, the CADET predictions matched the field and laboratory measurements within cm-accuracy for wave heights that ranged from 45 cm to 75 cm.

Jetty modification study for Kalaeloa Barbers Point Harbor, Hawaii

A series of laboratory experiments were conducted for a range of model ships, irregular waves, wave-induced longshore currents, and jetty lengths to optimize the length of a proposed entrance channel jetty at Kalaeloa Barbers Point Harbor, Hawaii. Eleven jetty configurations were studied on both sides of the entrance channel, with lengths varying from no jetty to incremental lengths up to 137 m (450 ft). Wave-induced ship motions were obtained for 392 inbound and outbound transits with 1:75 scale models of a C9-Class containership, a bulk-cargo carrier, and an ocean-going barge. In this paper, only the containership results are presented. A 114 m jetty (375 ft) on the north side of the channel and the 61 cm (2 ft) depth transition location inside the harbor were recommended. Copyright 2010 ASCE.

WAVE-CURRENT INTERACTIONS IN INLETS

A study of alternatives including a shoreline evolution numerical modelization has been carried out in order to both diagnose the erosion problem at the beaches located between Cambrils Harbour and Pixerota delta (Tarragona, Spain) and select nourishment alternatives.