Pricing Excavation and Backfill Chapter 10 Pricing Excavation and Backfill

Objectives Upon completion of this chapter, you will be able to: Describe the job factors and the labor and management factors that influence the price of excavation and backfill operations Use historic productivity rates to calculate the unit price of labor and equipment for excavation and backfill work

Objectives (cont’d.) Calculate the price of gravels and other backfill materials Calculate trucking requirements for hauling excavated material and gravels Complete the recap and pricing of excavation and backfill work using manual methods Use Excel spreadsheets to price excavation and backfill work

Excavation Equipment and Methods Specialized excavation contractors Concentrate on a single construction type: Vast array of excavation equipment Wide scope of work Common activities: Site cut and fill operations Basement-type excavations Trench excavations Pit and sump excavations

Excavation Equipment and Methods (cont’d.) Equipment transportation expenses: Priced on an item-by-item basis Site cut and fill operations: Equipment depends on project scale Basement excavations: Often performed with a track backhoe Large basements: one or more track loaders

Excavation Equipment and Methods (cont’d.) Trench excavations: Smaller trenches: trenching machines Larger trenches: backhoes Pit and sump excavations: Mostly performed using backhoes Hand excavation: Rarely used

Excavation Productivity Job factors: Type of material excavated or backfilled Moisture condition of materials Weather conditions expected Site access and project size/complexity Distance to haul materials for disposal Availability of gravels and fill materials Wage and price levels at the job location

Excavation Productivity (cont’d.) Labor and management factors Quality of job supervision Quality of job labor Motivation and morale of workers Type and quality of tools and equipment Experience and records of similar past projects

Excavation Work Crews Labor price per unit of excavation work Elements to consider: Number of workers that comprise the work crew and their trades Wage rates of trades involved Probable productivity rate of crew or equipment they are operating Productivity time factor

Productivity Rates Sources: Provided in publications (e.g., Means Building Construction Cost Data) Use with caution: general reflect ideal conditions Also available from manufacturers May be compiled from contractor’s own projects

Figure 10.3 Productivity of Hydraulic Excavators (Delmar/Cengage Learning)

Figure 10.4 Sample Data Record (Delmar/Cengage Learning)

Excavation Materials Mostly comprise gravels and fill materials: Required to meet designer’s specifications Backfilling Base courses under slabs and paving Pricing components: Supplying material to the site Spreading and compacting

Swell and Compaction Factors Excavated soil or gravel: Less dense Swell factor: Occupies more volume Compaction factor: Allowance for extra material required to fill volumes with compacted material

Calculating Trucking Requirements Determine optimum number of trucks required to transport materials Formula: Number of Trucks Required = Unloading Time/ Loading Time + One Example: Gravel Supply Pricing Refer to Pages 234 and 235

Additional Examples Excavation and Backfill Recap and Pricing Notes Example 1—House Refer to Pages 235 through 240 Excavation and Backfill Pricing Notes Example 2—Office/Warehouse Building Refer to Pages 240 through 244

Summary Many subcontractors perform excavation and backfill work Most specialize in some aspect Common methods: Site cut and fill operations Basement-type excavations Trench excavations Pit and sump excavations