FREE BOOKS

Author's List




PREV.   NEXT  
|<   3   4   5   6   7   8   9   10   11   12   13   14   15   >>  
rged gang planks, were used to connect the caissons. The pier was originally laid out as a letter "L," with a main leg of 300 ft. and a short leg of 36 ft. The pier head consisted of eight caissons in close contact, and was intended to form a breakwater, in the angle of which, and protected from the wave action, was to be moored the float and boat landing. After the first bids were received, the owner wished to reduce the cost, and every other caisson in the pier head was omitted, so that, as built, the pier contains eight caissons and five 53-ft. trusses. The caissons supporting the trusses are 8 ft. wide and 12 ft. long, and those in the pier head are 12 by 12 ft. On account of the shoal water and the great height of the outer caissons in comparison with their cross-section, it seemed advisable to mould them in two sections. The reinforcement in the side walls consisted of round 1/2-in. rods horizontally, and 3/8-in. rods vertically, spaced as shown on Fig. 1, together with cross-diaphragms as indicated. The caissons were reinforced for exterior pressures, which were to be expected during the launching and towing into position, and also for interior pressures, which were to be expected at low tide, when the water pressure would be nothing, but the filling of the caissons would be effective. The corners were reinforced and enlarged. In order to secure a proper bedding into the sand foundation, a 12-in. lip was allowed to project all around the caisson below the bottom. In the bottom there was cast a 3-in. hole, and this was closed by a plug while the lower section was being towed into place. The question of the effect of sea water on the concrete was given much thought. The writer is unable to find any authoritative opinions on this subject which are not directly controverted by equally authoritative opinions of a diametrically opposite nature. He thinks it is a question that this Society might well undertake to investigate promptly and thoroughly. There can be no question that there are many distressing instances of failures due to the action of sea water and frost on concrete, and that many able and experienced engineers in charge of the engineering departments of the great transportation companies have simply crossed concrete off their list of available materials when it comes to marine construction. It is a subject too large in itself to be discussed as subsidiary to a minor structure like the one herein desc
PREV.   NEXT  
|<   3   4   5   6   7   8   9   10   11   12   13   14   15   >>  



Top keywords:
caissons
 

question

 
concrete
 

section

 
trusses
 
bottom
 
authoritative
 

caisson

 

opinions

 

reinforced


subject

 

expected

 

pressures

 

consisted

 

action

 

planks

 

writer

 

connect

 

unable

 

nature


thinks

 

Society

 

opposite

 

diametrically

 
directly
 
controverted
 

equally

 

thought

 

letter

 

closed


effect

 
originally
 
undertake
 

marine

 

construction

 

materials

 

simply

 

crossed

 

structure

 
discussed

subsidiary
 
companies
 

distressing

 

project

 
investigate
 

promptly

 

instances

 

failures

 

charge

 
engineering