Commentary

The cost of deep dynamic compaction (DDC) is typically captured in two bid items:

• Design (for performance-based DDC project)
• Mobilization, normally lump sum
• Dynamic compaction, normally on a unit rate, either square feet or square yards
• Standby Rates

Other costs associated with DDC which may be measured and paid for separately include:

• Survey control staking
• Earthwork support to level a site and provide interim grading support in between high energy passes
• Material to restore the treated area back to original elevation, if required
• Working platforms materials
• Seismic cutoff trenches
• Full-time, remote Vibration Monitoring
• Post-improvement testing

Cost Information Summary

The following table lists items which are associated with the cost of DDC and are approximate cost ranges. Readers should carefully examine the project characteristics and constraints and determine to what degree if any these factors may influence the actual cost associated with the installation of DDC.

Table 1. Cost Information Summary

Pay Item Description	Quantity	Unit	Low Unit Price	High Unit Price	Factors Which May Potentially Impact Costs
Mobilization	1	LUMP SUM	$30,000	$120,000	Mobilization cost increases for greater distances and when larger equipment is required Phased projects may require multiple mobilizations
Deep Dynamic Compaction	10,000 sf to 1,000,000 sf	SF	$0.75	$4.00	Prices increase as tamper mass increases Excessive crater depth and/or groundwater reduces the production rate Grid spacing of DDC will affect the price per square foot Work in winter or frozen conditions also slows production and increases costs.
Material and Backfilling of Leveling Craters	–	CY	$3.00	$10.00	Material specifications and haul distance will impact unit costs Imported material will cost more than material that comes from on-site reuse

Historical Cost Information

Table 2. Tabulated Bid Information

Pay Item Description	Quantity	Unit	Low Unit Price	High Unit Price	Average Unit Price	No. of Bids	Bid Date	Source/Agency
Dynamic Compaction	122,850	SY	$15.00	$24.50	$18.15	6	1/25/24	Utah DOT

Conceptual Cost Estimating Tool

The conceptual cost estimating tool is intended to be used to develop a preliminary project scoping cost estimate. This preliminary estimate can be based on the typical construction cost item values as contained in the Cost Information product or from user specified cost values when such are known. Users should read and understand the information in Cost Information product prior to using the cost estimating tool. You can download the Cost Estimating Tool to open a cost estimating spreadsheet for producing a preliminary project scoping estimate.

 

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