3003 W CASINO RD BLDG 45-12 2016-10-20

777X Static Test Building I 13 We recommend the following for micropile installation. ■ Hart Crowser should observe micropile installation and testing to evaluate the contractor's operation and to collect and interpret the installation data. ■ The contractor and the designers must also be aware of the potential for obstructions within the fill and bearing layer. Although we have not yet encountered any significant buried debris, obstructions may be present. Major obstructions may require pile relocation. ■ To prevent interconnection of grout between piles, no two micropiles should be installed within 5 pile diameters of each other(center-to-center) in a single 12-hour period. ■ Micropiles in peat,soft silt, or loose sand materials should be cased to avoid excessive grout take. ■ The casing should be withdrawn from the hole slowly to maintain pressure on the grout column. RECOMMENDED ADDITIONAL GEOTECHNICAL SERVICES We recommend that before construction begins we review the final design plans and specifications to verify that the geotechnical engineering recommendations have been properly interpreted and implemented into the design. Monitoring, and testing by experienced geotechnical personnel should be considered an integral part of the construction process, because the performance and integrity of the structural elements of the project will depend largely on proper subgrade preparation, pile installation, and testing and construction procedures. We recommend that Hart Crowser be retained to provide these services. The purpose of our observations would be to verify compliance with design concepts and recommendations, and to allow design changes or evaluation of appropriate construction methods in the event that subsurface conditions differ from those anticipated prior to the start of construction. During project construction, we recommend that a Hart Crowser representative observe the following construction activities: ■ Micropile installation and load testing; ■ Installation of soldier piles; ■ All exposed footing subgrades(to confirm that suitable soil conditions have been reached for the proposed allowable bearing pressures); ■ Drainage installation; and ■ Placement and compaction of all structural fills. This one activity may alternatively be performed by a qualified construction testing firm. WE ALM 19106-01 HAUCITOwSME May 29,2015