TRANSACTIONS OF SECTION G. 799 



2. Louisville and New Albany Bridge. 

 By T. C. Clakke and C. Macdonald. 



The paper confined itself mainly to a consideration of novel features in the super- 

 structure of this cantilever bridge recently built by the Union Bridge Co. of New 

 York over the Ohio River. 



The structure consists of two main cantilever spans, 480 ft. and 483 ft. long 

 respectively, from centres of piers, joined by a continuous span of 360 ft., two 

 anchor spans of 260 ft. each, a swinging span 370 ft., and a fixed span at the New 

 Albany end 240 ft. long, making a total length of 2,453 ft. between centres of 

 abutment cylinders. 



After describing a number of accompanying photographs, mention was made of 

 the fact that, in consequence of the current in what is known as the ' Canal Chan- 

 nel ' which passes under the 483 ft. span being at an angle of 60° to the axis of the 

 bridge, it was thought necessary to construct skew piers for this span, with their 

 faces parallel to the direction of current, the details being thereby much com- 

 plicated. 



Normally all river traffic passes under this span, but at high water the 480 foot 

 span is use4. 



The several dimensions of the bridge, total width of which is 49 feet, were then 

 given. Open hearth steel was employed in its construction, and, for compression 

 members, sample bars f in. in diameter were required to show an elastic limit of 

 not less than 50,000 lbs. per sq. in., an ultimate strength of 80,000 lbs., elongation 

 of 15 per cent, in 8 inches, and reduction of area at point of fracture of 35 per 

 cent. The carbon ranged from 0-34 to 0'42 per cent., and phosphorus was under 

 O'lOO. Full-sized bars were allowed an elastic limit of 35,000 lbs., and ultimate 

 strength of 65,000 lbs. The wrought iron plates had an elastic limit for standard 

 sample bar of 24,000 lbs., ultimate strength of 47,000 lbs., elongation of 10 per 

 cent., and reduction of area of 15 per cent. 



The structure is designed to carry 1,200 lbs. per foot on the roadway and side- 

 walks as well as the following load on the railway — a train weighing 2,240 lbs. 

 per foot drawn by two locomotives and tenders, weighing 356,000 lbs, together. 

 Wind strains resist a force at right angles to the axis of 450 lbs. per foot of span on 

 lower lateral system, and 150 lbs. on the upper. 



In connection with the work of erection it was pointed out that the Ohio River is 

 subject to extraordinary floods, when quantities of ice and drift are carried down by a 

 current of more than six miles per hour. On one occasion during erection the river 

 rose 57 feet in six days, and frequently to a height of 25 or 35 feet. 



The work was commenced in the spring of 1885, and after a satisfactory series 

 of tests had been made in June last the bridge was thrown open to the public. 



The total weight of metal in the bridge is 6,000,000 lbs., or at the rate of 

 1'09 tons, or 2,446 lbs., per lineal foot. 



3. Freezing as an Aid to the Sinking of Foundations. By 0. Reichenbach. 



After referring to the extended use that has been advantageously made of 

 caissons as a means of founding the supports of bridges at great depths, especially 

 in India over the Sutlej and Ganges, the author referred to the difficulties experienced 

 when, adopting this method, obstructions or boulders are met with far below the 

 surface, or where the piers are finally founded on rock of an imeven surface. 

 Whereas piers have been founded at depths of 140 feet below water-level by this 

 method, the pneumatic method, to which preference was given in the case of the 

 St. Louis Bridge over the Mississippi, is limited in its application to depths of 

 about 120 feet. An instance of well-sinking in 1862 by freezing the ground was 

 mentioned. A method of sinking foundations was patented by Mr. F. Poetsch in 

 1883. It consists in freezing the water contained in the siuTounding groimd, and 

 thus providing a watertight lining, which enables the necessary excavations to be 



