250 PARKS 



Man Hours per one hundred linear feet of trench excavated 



Depth of Average width Easy Average Tough Hard- 



trench of trench earth earth earth pan 



1 foot 12 inches 3.7 4.6 6.5 9.2 



2 feet 15 inches 9 n.6 16 23 



3 feet 1 8 inches 20.8 25 33 50 



4 feet 1 8 inches 33 39 50 77 



5 feet 21 inches 81 130 



6 feet 24 inches 122 



When restricted areas compel the disposal of excavation on one side 

 of the trench only, the man hours should be increased one-sixth to cover 

 the extra labor required to keep the material pushed back from the edge 

 of the trench. In any excavation work where it is necessary to handle 

 materials twice, always endeavor to shovel the material on planks in order 

 to decrease the cost of handling it the second time, as materials can be 

 handled at nearly half the cost if shoveled from planks. 



Trench excavation (shallow trench not over six feet deep, see Plate 108, 

 figures 2 and 3). 



Depth of excavation, 3 feet. 



Width of trench, 18 inches. 



Total length of trench excavated, 2,113 feet. 



Total excavation, 359 cubic yards. 



Total labor hours required, 722. 



Labor hours required per cubic yard of excavation, 2.01. 



Labor hours required per linear foot of trench, .342. 



Deep trenches. In excavating trenches more than six feet deep it will 

 be necessary to shovel the earth back from the edge of the trench even for 

 narrow trenches. Loose earth just thrown out of trenches is easily handled, 

 especially if that handling consists in merely pushing it back from the edge 

 of the trench. For trenches from six to eight feet deep, one-half of the 

 total excavation will be handled twice, the second handling costing only 

 one-third that of the first. The following rates in man hours per cubic 

 yard will cover the cost of initial materials handled for trenches six to eight 

 feet deep: 



Easy earth, 2 man hours. 



Average earth, 2.5 man hours. 



Tough earth, 2.75 man hours. 



Hardpan or wet clay, 4 man hours. 



Therefore the average cost per cubic yard in man hours for trenches 

 from six to eight feet deep will be: 



Easy earth, 2.33 man hours. 



