134 



After the caissons were constructed on shore, the ends were sealed with timber 

 bulkheads, and they were launched and floated to the site. They were then sunk 

 into position, their lower ends resting in holes previously excavated in the mud down 

 to hardpan. The bottoms of these holes were covered with a layer of crushed rock. 

 Five piles were then dri\en in each of the three compartments, the cut-offs being 

 several feet above the bottom of the caissons. The bottoms were sealed by placing 

 about 12 feet of tremie concrete. The caissons were then pumped dry and filled solid 

 with concrete. 



Fig. 54. l)ii\iiig cylindrical forms, California-Hawaiian Sugar Refining Co. warehouse, Crockett. 

 Note outer hoops and rods for pulling wedge pins. 



LARGE MASS-CONCRETE CYLINDER PIERS CONSTRUCTED 

 IN OPEN REMOVABLE TIMBER CAISSONS 



The California-Hawaiian Sugar Refining Co. has developed a large mass-concrete 

 substructure pier, required because of the extremely heavy floor loadings of their 

 warehouses, at their Crockett refinery. The floor load in question is about 2,000 

 pounds per square foot. The concrete piers are 6 feet in diameter and are carried down 

 to hardpan, in some cases 60 feet below the wharf level. No reinforcement is used. 

 They are spaced at about 16 feet centers in both directions and support a floor system 

 of groined arches with a 9-inch floor slab. 



The sequence of construction is as follows: Cylinder forms, with an inside di- 

 ameter of 6 feet and lengths up to 50 feet, are made with 4, 6 or 8-inch redwood staves. 

 The individual stave pieces are held in position in the form by removable interior 



