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RVC Homes <br /> Project BABX-01-0124 <br /> April 12, 2001 <br /> Page 8 <br /> C.7. Surcharging <br /> Unacceptable amounts of settlement may occur, especially if more than a few feet of additional fill is <br /> placed. To reduce future settlements, we recommend a surcharge be placed exceeding the desired final <br /> grade elevation, and the elevation of the surcharged be monitored over a period of time. After the rate <br /> of settlement has decreased,the surcharge can be removed and exterior features constructed. <br /> D. Construction <br /> D.1. Pile Hammer <br /> We recommend the piles be driven using a hammer with a manufacturer's rated energy ranging from <br /> 15,000 to 30,000 foot-pounds and be capable of transferring 7,000 to 15,000 foot-pounds of energy. <br /> Care must be taken not to overstress (and possibly damage)the piles. Prior to acceptance, we <br /> recommend a wave equation analysis be performed to evaluate the contractor's proposed driving <br /> system. <br /> D.2. Test Piles <br /> We recommend pile capacity be determined using wave equation analysis and dynamic pile tests. As <br /> shown above, with the use of wave equation analysis and dynamic pile tests, the recommended factor of <br /> safety is 2.25. We will be pleased to discuss wave equation analysis and dynamic pile testing with you <br /> and our experience with using these pile analysis and testing tools on similar projects. <br /> When installing the piling, if the penetration resistance to driving does not meet the required value after <br /> driving to a pile toe elevation of 5 feet below the anticipated depth needed to develop the <br /> design-working load, we recommend driving be halted and that the capacity be evaluated on restrike <br /> after allowing for soil set-up to occur. If the pile tip is driven past the estimated lengths shown in <br /> Tables 1 and 2, it is probable the piles have been overdriven and, after soil setup occurs, the pile <br /> working loads could be higher than necessary. <br /> D.3. Production Pile Observations <br /> All pile installed for the project should be driven in the presence of an experienced engineering <br /> assistant. The qualified personnel should document pertinent pile information such as pile length, <br /> elevations and driving resistances. This person should also document that the recommended <br /> driving/length criteria have been achieved for the piles. <br />