Section III., 1914 [29] Trans. R.S.C. 



The Expansive Force of Ice. 

 By H. T. Barnes, J. W. Hayward and Norman M. McLeod. 



(Read May 27, 1914.) 



The expansive force of ice is a matter of very great importance 

 in engineering work. In the design of concrete dams the amount of 

 allowance for the thrust of the ice sheet, is as yet a somewhat uncertain 

 factor. Engineers are divided as to the amount to be allowed. 



C. A. Mees gives some of the values which are assumed by various 

 authorities in the design of dams. He gives the following: 



G. P. Stearns (Wachusett Dam) — 47,000 lbs. per linear foot. 



Board of Experts (Quaker Bridge Dam) — 43,0001bs. per linear foot. 



J. D. Van Buren (Tran. Am. So. CE.)— 40,000 lbs. per linear foot. 



S. M. Gray (Columbus, Ohio) — 34,000 lbs. per linear foot. 



He works out, from data on the modulus of elasticity of ice by 

 taking the crushing strength of ice as 400 lbs. per square inch, values 

 similar to these. He admits that according to his references, the 

 case of a failure of a dam, which he studied, was caused not by pure 

 temperature expansion, but more probably by a change in water 

 level. 



A more recent paper by Mr. Walter H. Sawyer (Proceedings 

 Maine Society of Civil Engineers, Vol. I, p. 27, 1911) — gives a very 

 clear and satisfactory account of his direct observations of the ice 

 thrust on several large lakes. He gives also some very valuable 

 measurements of the expansion coefficient of ice at different tempera- 

 tures. He cites authorities as follows: — 



Wegmann (Croton Dam) 43 , 000 lbs. 



Morrison and Brodie 47 ,000 " 



In his own work on the construction of the Azicohos Dam on 

 the Magalloway River he was obliged to select a value for the ice 

 thrust, but owing as he says, "to the meagre information on this 

 subject," it was difficult to arrive at any definite conclusion. Experi- 

 ments were therefore undertaken by Mr. Sawyer to determine the 

 thermal expansion and contraction of ice at different temperatures, 

 the crushing strength of ice, and the tensile strength. 



Mr. Sawyer's first observations were made of the expansion 

 ridges or "wrinkles" on some of the Maine lakes which were observed 



