scholarly journals ANALYSIS OF 42-TON DOLOS MOTIONS AT CRESCENT CITY

1988 ◽  
Vol 1 (21) ◽  
pp. 158 ◽  
Author(s):  
Thomas R. Kendall

Photogrammetry has been applied to make precise measurements of post-construction displacements of 38.2-metric ton (42-ton) dolosse on the outer breakwater at Crescent City, California. Data from two storm seasons are currently available from this monitoring program which was initiated in November 1986 and which is expected to continue at least through the next three winters. Supplemented by conventional land surveys, wave measurements, aerial inspections, and side scan sonar underwater imagery, observations from the photogrammetric monitoring have led to several preliminary conclusions regarding regions of relatively large dolos movement, dolos nesting, the dependency on breakwater slope of uprush or drawdown dominated armor unit movement, and the relative importance of armor unit movement and boundary conditions in dolos breakage. This paper describes the methods used for, and results obtained from, this monitoring effort along with the application of these results to a Corps study (Howell, 1988) Whose objective is to develop structural design criteria for the dolos concrete armor unit.

1988 ◽  
Vol 1 (21) ◽  
pp. 174 ◽  
Author(s):  
Gary L. Howell

In-situ measurements of the structural bending moments and torque about the shank-fluke interface of the dolos armor unit have been made for 42-ton (36-metric tonne) dolosse at Crescent City, California jetty. The measurements include the static loads on the dolosse as well as wave induced forces. The data were obtained from internal strain gages cast into the dolos during construction along with a special data acquisition system. The measurement system was also capable of capturing impact forces caused by dolos rocking or movement. Measurements were made during the winter storm seasons from January 1987 through May 1988. Coincident with the structural measurements, wave height and period were measured at several water depths approaching the breakwater, including a site directly in front of the dolos test section. The Crescent City jetty is a shallow water breakwater with depth limited waves in about 10 meters of water depth. The structural measurements were made from 14 dolos units arranged in a rectangular section on the top layer of the trunk portion of the jetty. Four of these dolosse are also instrumented with an accelerometer platform to measure motion with six degrees of freedom. In addition, there are three instrumented dolosse on the bottom layer of the breakwater. These dolosse measure the static stress due to the units placed on top of them, as well as pulsating forces. The structural and wave measurements, reported here, are supplemented with hydrostatic pore pressure measurements in the core material of the breakwater, and by aerial photogrammetric motion analysis (Kendall, 1988), land based surveys, boudary condition surveys, hydrographic surveys, and side scan sonar surveys.


Shore & Beach ◽  
2020 ◽  
pp. 102-109
Author(s):  
Syed Khalil ◽  
Beth Forrest ◽  
Mike Lowiec ◽  
Beau Suthard ◽  
Richard Raynie ◽  
...  

The System Wide Assessment and Monitoring Program (SWAMP) was implemented by the Louisiana Coastal Protection and Restoration Authority (CPRA) to develop an Adaptive Management Implementation Plan (AMIP). SWAMP ensures that a comprehensive network of coastal data collection/monitoring activities is in place to support the development and implementation of Louisiana’s coastal protection and restoration program. Monitoring of physical terrain is an important parameter of SWAMP. For the first time a systematic approach was adopted to undertake a geophysical (bathymetric, side-scan sonar, sub-bottom profile, and magnetometer) survey along more than 5,000 nautical miles (nm) (excluding the 1,559 nm currently being surveyed from west of Terrebonne Bay to Sabine Lake) of track-line in almost all of the bays and lakes from Chandeleur Sound in the east to Terrebonne Bay in the west. This data collection effort complements the regional bathymetric survey undertaken under the Barrier Island Comprehensive Monitoring (BICM) Program in the adjacent offshore areas. This paper describes how a study of this magnitude was conceptualized, planned, and executed along the entire Louisiana coast. It is important to note that the initial intent was to collect bathymetric data only for numerical modelling for ecosystem restoration and storm surge prediction. Geophysical data were added for oyster identification and delineation. These first-order data also help comprehend the regional subsurface geology essential for sediment exploration to support Louisiana’s marsh and barrier island restoration projects.


2004 ◽  
Vol 329-333 ◽  
pp. 1615-1618 ◽  
Author(s):  
G.M Kalinin ◽  
B.S Rodchenkov ◽  
V.A Pechenkin

2017 ◽  
Vol 42 (1) ◽  
pp. 24-46 ◽  
Author(s):  
Alexander McKelvie ◽  
Johan Wiklund ◽  
Anna Brattström

We investigate the relative importance of external market knowledge acquisition and internal knowledge generation in new venture innovation. We argue that the effectiveness of externally acquired knowledge is less important in environments that are perceived as highly dynamic. To test our model, we examine 316 new ventures in one singular, high-growth sector. We find that managers have different interpretations of dynamism within this single sector and that these perceptual variations have important implications for how new ventures develop knowledge in pursuit of innovation. In so doing, we illustrate important within-sector mechanisms and boundary conditions behind new venture knowledge development and innovation.


1955 ◽  
Vol 59 (530) ◽  
pp. 120-126 ◽  
Author(s):  
V. Cadambe ◽  
S. Krishnan

The minimum weight approach to structural design was introduced by F. R. Shanley with reference to narrow and wide columns and shells subjected to bending, and was later dealt with more comprehensively in a book by the same author. This was further extended to structures like tapered round thin-walled columns and frames. In this paper expressions giving optimum sectional dimensions for long thin walled cells of circular, semi–circular, rectangular and triangular shapes and uniform wall thickness have been derived. The design criteria used to obtain the minimum necessary conditions are (1) failure by local buckling and (2) a limit on the twisting deformation of the cells. Working curves from which the optimum sectional dimensions can be read for given torque and limiting twist have been plotted. And finally, a method of approach to the problem of combined bending and torsion has also been indicated.


1974 ◽  
Vol 1 (14) ◽  
pp. 143
Author(s):  
C.S. Fang ◽  
G. Parker ◽  
W. Harrison

A hydrothermal monitoring program has been designed and deployed to gather data on the temperature distribution in the tidal James River near the outfall of the Surry Nuclear Power Plant at Surry, Virginia, U.S.A. Monitoring to date has included two years of background data (1971 and 1972) taken prior to plant operation, and one year (19 73) of data with the plant in operation. The results of the first year post operational monitoring effort has been compared with the pre-operation background data and with the thermal effects that were predicted from studies by Carpenter and Pritchard on the James River Hydraulic Model at Vicksburg, Mississippi.


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