573AGGREGATE FOUNDATIONS

464

A drawing of the plan view of the aggregate foundations shall be submitted. The following details shall be shown on the plan view:  A reference baseline;  The offset from the construction centerline or baseline to the foundations;  Size and alignment of the foundations;  Right-of-way and permanent or temporary construction easements limits, location of all known active and abandoned existing utilities, adjacent structures and other potential interferences.  The centerline of any drainage structure or drainage pipe behind, passing through, or passing under the foundations;

A drawing of the elevation view of the aggregate foundations shall be submitted. The following details shall be shown on the elevation view:  The elevation at the top and bottom of the foundations;  Size and alignment of the foundations;  Schematic and elevations of the structures supported by the foundations;  The centerline of any drainage structure or drainage pipe behind, passing through, or passing under the foundations.

Construction procedures shall be submitted to identify all of the processes, equipment, tools and materials required for the construction and testing of the aggregate foundations. A quality control plan and examples of forms proposed for the documentation of construction daily progress reports and testing shall be submitted with the construction procedures.

573.05Approved List of Aggregate Foundation Specialty Contractors

The following aggregate foundation design-build specialty Contractors are approved to perform the work:  Geopier Rammed Aggregate Piers; Geopier Foundation Company; 150 Fairview Road, Suite 335; Mooresville, North Carolina 28117;  Vibro-Pier; Keller North America, Inc.; 2 Perimeter Park South, Suite 229E Birmingham, AL 35243; William Wright, P.E. Phone: 205-890-9210. Other aggregate foundation specialty Contractors will be given consideration for approval. Consideration for approval will be given to specialty Contractors that can provide documentation that they have successfully designed and constructed at least 3 projects in the last 3 years where the construction of permanent aggregate foundation totals at least 50 foundations.

573.06Construction Requirements

The foundation excavation, construction and testing shall be performed in accordance with the requirements shown on the submittal of foundations details and construction procedures distributed by the Engineer.

The Contractor shall furnish a complete and accurate record of aggregate foundation installation to the Engineer. The record shall indicate the foundation location, length, drilled diameter, average lift thickness, and final elevations of the base and top of the foundations. The record shall also indicate the type and size of the densification equipment used. The Contractor shall immediately report any unusual conditions encountered during installation to the Engineer.

Excavation shall be extended if the Engineer determines that further excavation is necessary for the removal of soft or yielding areas that may be uncovered. Sheeting and shoring may be required to protect the site of the excavation. Excavation will be paid for under other items of work (Section 210). Sheeting and shoring will also be paid for under other items of work (Section 215). AGGREGATE FOUNDATIONS 465

Aggregate foundations shall be installed so that each completed foundation (column) will be continuous throughout its length. The center of the completed foundation (column) shall be within 6 inches from the required horizontal location. The vertical alignment tolerance shall be a maximum of 2 inches horizontal for every 10 feet vertical of depth. The completed aggregate foundation diameter shall not be less than 10 percent smaller than the required diameter. The top of the ground improvement provided by the aggregate foundations shall be within 6 inches of the required elevation. Aggregate foundations shall be installed in a sequence that will minimize ground heave. Any heaving shall be re-compacted or excavated as directed by the Engineer prior to wall or embankment construction and be considered incidental to aggregate foundation construction.

A modulus test shall be performed to verify the performance values selected for design. A telltale shall be installed at the bottom of a test foundation so that the deflection at the bottom of the column can be measured. The modulus test shall be conducted at a location where the bottom of the column terminates in soil. Acceptable performance is when the deflection of the bottom of the foundation is no more than 20 % of the deflection at the top of the foundation at the design stress level. ASTM D-1143 general test procedures shall be used to establish load increments, load increment duration, and load decrements. With the exception of the load increment representing approximately 115 % of the design maximum foundation stress, all load increments shall be held for a minimum of 15 minutes, a maximum of 1 hour, and until the rate of deflection reduces to 0.01 inches per hour or less. The load increment that represents approximately 115 % of the design maximum stress on the foundation shall be held for a minimum of 15 minutes, a maximum of 4 hours and until the rate of deflection reduces to 0.01 inches per hour or less. A seating load equal to 5 % of the total load shall be applied to the loaded steel plate prior to application of load increments and prior to measurement of deflections to compensate for uneven surface conditions. The location of the modulus test will be determined by the Engineer.

After completion of the construction of the bottom of the foundation, or at any time during the process of constructing the foundation a bottom stabilization verification test may be performed as required by the Engineer. These tests shall be performed when a new soil formation is encountered, at the beginning of a project to provide quantitative information on foundation stabilization, and on 10 % of production foundations. Bottom stabilization tests shall be performed by placing a reference bar over the excavated cavity, marking the tamper shaft, applying energy to the tamper for an additional 15 seconds, and observing the downward deflection of the tamper shaft by observing the deflection of the mark on the tamper shaft. Acceptable performance is indicated if the movement of the shaft is less than 150 % of the vertical movement measured at the bottom of the foundation during the modulus test. If the measured vertical movement exceeds 150 % of the value measured during the modulus test, added energy shall be applied to further compact the aggregate. The procedure for measuring the movement shall then be repeated. If there is still movement greater than 150 % of that achieved during the modulus test and the movement is greater than 0.5 inches, a lift of loose aggregate may be placed on top of the compacted aggregate, and the verification test may be performed on this next lift after it is densified. If there is excessive movement on this lift, another lift may be placed and tested. Movement must be limited to below 150 % of the movement determined from the modulus test before completion of 2/3 of the depth of the foundation.

573.07Method of Measurement

The Aggregate Foundations will be measured in units of cubic yards. The pay quantity for Aggregate Foundations shall be the volume calculated by multiplying the plan area of improvement by the average depth of the aggregate foundations installed during construction. MOBILIZATION 466

573.08Basis of Payment

The Aggregate Foundations will be paid for at the contract unit price. This payment shall be full compensation for all submittals, labor, equipment, tools, materials, material tests, field tests and incidentals necessary to acceptably construct the foundations.

573-A Aggregate Foundations – per cubic yard

600.01Description

This Section shall cover the preparatory work and operations including, but not limited to, those necessary for the movement of personnel, equipment, supplies, and incidentals to the project site; for the establishment of all offices, buildings, and other facilities necessary for work on the project; and for all other work and operations which must be performed or costs incurred prior to beginning work on the various items on the project site. The lump sum bid for mobilization shall be so distributed among the various pay items of the contract that an overrun of a particular pay item will not adversely affect the unit price of that item.

600.02Materials

Not applicable.

600.03Construction Details

Not applicable.

600.04Method of Measurement

When more than one project is included in one contract, the amount of payment to be made will be based on the "Percent Complete" as defined in Article 108.04 and amount of the entire contract, not the amount of each individual project. Once the amount of payment is determined, based on the entire contract, this amount will then be prepared for payment on each individual project based on the fraction of the total contract of which the project is a part. Partial Payments for mobilization are based on the Percent Complete and the total adjusted contract amount for all items of work. Payments will be made at the time, and in the amounts shown in the following schedules.