Excavator Production Estimating in Pipe Applications    

ESTIMATING PURPOSES ONLY
 
  Excavator w/o Coupler  
Use tab key for data entry  
Trench Depth (ft.)       Calculations for Excavation Time (no pipe placement)  
        Stable Type Type Type Type "A" Type "B" Type "C"  
Trench Width at Bottom (ft.)   Rock A soil B soil C soil W/ T-box W/ T-box W/ T-box  
        Top Width (ft. =  
Trench Length Per Section (ft)   Cu.Yd. / section =  
        Cu.Yd. / day =  
Total Sections per Day                      
        Cycles / section =  
Bucket Capacity (cu. yd.)   Time/dig (min) =  
                     
Excavator Cycle Time (sec.)   Cycles / day =  
        Time/day (min) =  
Height of Trenchbox (ft.)     Time/day (hr.) =  
               
Time for Pipe Setting (min.) [Bedding and Joining Sections]   Time to Goal: Pipe Placement in Work Hours  
    Hrs. needed for Goal  
Hours Worked / Day     Feet inst. in Day.  
       
Minutes Worked / Hour           (Trench Length) X (Total Sections)= feet per day (Trench Goal)  
 
 
  Excavator with Coupler and Two Buckets  
  Calculation adds 2 min. for coupler/bucket swap (1 ea.)  
  Calculations for Excavation Time (no pipe placement)  
    Stable Type Type Type Type "A" Type "B" Type "C"  
Bucket Capacity (cu. yd.) Used for Top of Trench     Rock A soil B soil C soil W/ T-box W/ T-box W/ T-box  
    Cycles / dig =  
  Time/dig (min) =  
                     
  Cycles / day =  
Note: Even if job is planned using one bucket,   Time/day (min) =  
enter a larger bucket for the top of the trench   Time/day (hr.) =  
for comparison purposes. Total feet dug from        
the bottom should be height of trench box or   Time to Goal vs. Pipe Placement in Work Hours  
five feet (OSHA guideline).     Hrs. needed for Goal  
  Feet inst. in Day.  
 
Excavator Reach and Spoil Pile Volume  
 
    A   B  
  Volume Excavated IF Capability of Excavator  
Max. Dump Ht. (ft.)   Type Bank Volume Possible Total Adjusted Possible Adjusted    
  Soil yards in Spoil Exceeds Pile Spoil Pile Pile Pile    
Max Reach (ft.)     Excavated Pile Vol. (yd.) Setback Ht. (ft.) Base (ft) Base (ft)    
  Stable (cu. yd.) w/(swell)   calculated (ft.) calculated calculated calculated    
Swell Percent   Rock    
(See Table Below)   A    
B    
C  
A w/T-box    
B w/T-box    
C w/T-box    
  Note: Volumes are per linear foot.  
Example of wide-cut trench where amount of material plus swell to be excavated exceeds the largest possible volume of the spoil windrow.  
 
In excavations where Col. A (excavated volume) exceeds Col. B (maximum spoil volume possible), you have a problem, as illustrated in the diagram above. You need a longer reach or larger excavator. Even when A and B are equal, the operation is not efficient. It means that the excavator must swing a full 90 degrees and be at its max dump height. Of course the use of a trenchbox for wide/deep cuts permits the deployment of a smaller excavator and/or shorter cycle times.  
 
 
 
 
 
 
 
Swell Percentages Table  
 
  Material   Swell %   Material   Swell %  
  Caliche   81   Sand, Dry 12  
  Clay, Natural Bed 22   Sand, Moist 12  
  Clay, Dry   23   Sand, Wet 12  
  Clay, Wet 25   Sandstone 67  
  Clay & Gravel, Dry 18   Sand & Gravel, Dry 12  
  Clay & Gravel, Wet 18   Sand & Gravel, Wet 10  
  Earth, Dry Loam 25   Topsoil   43  
  Earth, Moist Loam 27    
  Gravel, Dry 12    
  Gravel, Wet 12    
  Gravel, Pit Run 12