Call number:
ZSP-201-77/4
In:
CRREL Report, 77-4
Description / Table of Contents:
The ice booms on the St. Marys River at Sault Ste.Marie, Michigan and Ontario, were operated a second winter, 1976-77, under colder conditions, with less water flow, lower water levels, and 25% fewer ships in the river than during the previous year. The ice cover behind the booms remained frozen to shore for longer periods, and the loads registered in the booms were relatively unaffected by ship passages compared with the previous year's activity. As in the previous year, most structural load changes took place in the west ice boom and were due to movements of the ice cover immediately upstream of the boom. The cover broke free from shore on three occasions: the first and third occasions were minor events, but on the second occasion the cover cracked free, the timbers remained frozen to it, and the boom structure became damaged by the subsequent ice activity. Three anchor line assemblies broke over a period of about 4 hours; the two latter breaks occurred while a ship was operating in the ice. The first break was in an instrumented line and the measured load was unexpectedly low. The most important break was in the main shore anchor and this opened the boom. The maximum force at this anchor was estimated as less than 115 tons (1,023 kN). Some ice moved downstream without serious consequence and the boom was reconnected in two days. These events point out several factors to be considered in ice booms, such as designing the booms to withstand the action of the solid ice cover as well as the fragmented ice cover, keeping the structures and their assembly simple, and inspecting components and assemblies carefully.
Type of Medium:
Series available for loan
Pages:
vi, 26 Seiten
,
Illustrationen
Series Statement:
CRREL Report 77-4
URL:
https://hdl.handle.net/11681/9478
Language:
English
Note:
CONTENTS
Abstract
Preface
Summary
Introduction
Ice boom basic principles
General loading considerations
Design ice areas
Prediction of ice boom loads
Summary
Ice cover forces
Ice barrier reaction force
Ice forces in the structure
Analytical relationships
Design force summary
Special features
Extension of west ice boom
Pipe restraint structure
Diagonal anchor cables
Measurement systems
Measured anchor cable forces
Data records
Average and peak loads
Ice activity on or about 1 February 1976
C3W cable forces
Ship-induced leads
Ice cover load check
Conclusions
Recommendations
Literature cited
Appendix A. St. Marys River ice booms test data
Location:
AWI Archive
Branch Library:
AWI Library
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