Structural Ice Control Review of Existing Methods

Structural Ice Control

Review of Existing Methods

ANDREW M. TUTHILL

INTRODUCTION

of application. Within each category, examples

then illustrate a variety of structure types. A

Structural solutions exist for a wide range of

conclusions section then summarizes the current

river ice problems. This report reviews a variety

state of knowledge in the field of structural ice

of structural ice control methods in use today,

control, pointing to areas where new methods or

focusing on recent performance. A main goal is

applications might be possible. The conclusions

to determine which areas of structural ice con-

also assess the applicability of selected structural

trol are well developed and understood at

methods to various confluence ice situations.

present, and which ice problems do not lend

The typical hydraulic conditions of channel

themselves to a solution by current structural

depth and water current velocity for different

methods. It is also hoped that the information

types of structures are also considered in the

assembled through this work will provide guid-

conclusions. Finally, Appendix A, an inventory

ance in selecting and adapting structural ice con-

of structures, serves as a database, containing

trol methods for specific confluence ice prob-

tabular information on design, construction ma-

lems.

terials, hydraulic conditions and recent perfor-

Ice control research and development during

mance.

the last three decades has concentrated on sheet

ice retention methods. Much of this work is de-

BACKGROUND

scribed by Perham (1983) and Appendix B of the

Ice Engineering Manual (U.S. Army Corps of

The last three decades have seen much devel-

Engineers 1985). The difficult problem of break-

opment in the field of structural ice control. The

up ice control has received less attention, partic-

following is a brief summary of the general liter-

ularly on larger rivers. This report serves as a

ature on structural ice control methods. Litera-

supplement to Perham's 1983 review, emphasiz-

ture relating to single structures will be cited

ing recent developments in structural ice control

where appropriate later in the report.

as well as methods that could be applied to ice

"Winter Regime of Rivers and Lakes" by

problems characteristic of river confluences. Few

Michel (1971) provides good background on

constraints have been placed on geographic

river ice processes affecting the design of dams

location, scale or structure type. Locations

and booms to control frazil and breakup ice.

include sites in the northern United States, Can-

During the sixties and seventies, the navigation

ada, northern Europe and Japan.

and hydropower interests, along with various

A background section summarizes past re-

government agencies in the U.S. and Canada,

views on structural ice control. Structures are

fostered the successful development of sheet ice

then placed in three categories according to their

retention methods on the St. Lawrence River

main purpose: sheet ice retention, breakup ice

and the connecting channels of the Great Lakes.

control or ice diversion. The ice control objec-

Perham (1983) and Appendix B of the Ice Engi-

tives of each category are discussed, along with

neering Manual (U.S. Army Corps of Engineers

general design considerations and typical ranges

1985) provide descriptions of many of these