131 211.9 -PAY ITEMS : ITEM DESCRIPTION UNIT 211001 -* Unclassified Borrow Excavation Cubic Yard 211002 -* Rock Borrow Excavation Cubic Yard 211003 -* Select Borrow Excavation Cubic Yard 211007 -* Unclassified Borrow Excavation Ton 211008 -* Rock Borrow Excavation Ton 211009 -* Select Borrow Excavation Ton 211017 -* Impervious Core Square Foot
* Sequence number
132 SECTION 212 STRUCTURE, ROCK, AND WET EXCAVATION
212.1 -DESCRIPTION : This work shall consist of the excavation and backfill or disposal of all materials required to be removed for the construction of retaining walls, box culverts, catch basins, drop inlets, manholes, bridge foundations, and other structures for which excavation is not otherwise provided; the removal of all old structures, including abutments, piers and w ingwalls, unless otherwise specified or directed; in accordance with these Specifications and in reasonably close conformity with the lines, grades and typical cross sections shown on the Plans or established by the Engineer. It shall include pumping, dra ining, sheeting, and constructing cribs and cofferdams if necessary.
212.2 -MATERIALS : Select material for backfilling shall be crushed stone, gravel, slag, or any combination thereof meeting the requirements of Section 703. The grading shall be such that 100 percent (100%) of the material passes the 2 inch (50 mm) sieve and 0 to 5 percent (0-5%) passes the No. 16 (1.18 mm) sieve. Any of the standard coarse aggregate sizes from AASHTO No . 4 thro ugh AASHTO No. 8, as shown in Table 703.4, would comply with the above gradation requirement. Controlled low strength material shall meet the requirements of Section 219. Quality Control of select material for backfilling is the responsibility of the Con tractor as specified in 106.1. Engineering fabric shall be fabric for subsurface drainage or separation meeting Subsection
715.11
212.2.1 -Quality Control Testing: Quality control of the select material for backfill is the responsibility of the Contra ctor as specified in Subsection 106.1. The Contractor shall maintain necessary equipment and qualified personnel to perform all sampling and testing necessary to determine the magnitude of the various properties of the material governed by the Specifications and shall maintain these properties within the limits of the Specifications. The Contractor shall submit a quality control plan detailing the methods by which the quality control program will be conducted. This plan, prepared in accordance with the guidelines set forth in the appropriate portions of MP 307.00.50 and MP 717.04.21, shall be submitted to the Engineer at the preconstruction conference. The work shall not begin until the plan is reviewed for conformance with the contract documents.
212.2.2 -Acceptance Testing: Quality control sampling and testing performed by the Contractor shall be used by the Division for acceptance .
212.2.3 -Sampling and Testing: Frequency of sampling and testing shall be in accordance with the Contractor’s qua lity control plan. The minimum sampling and testing frequencies for gradation shall be as indicated in Attachment 1 of MP 307.00.50. The material shall be sampled in accordance with MP 700.00.06. The minimum sampling and testing frequency for compaction will be in accordance with MP 700.00.24.
133 212.2.4 -Acceptance Procedure: Material conforming to the specification requirements will be accepted at full contract price. Material failing to comply with the quality requirements of Table 704.6.2B shall not be incorporated into the work. Acceptance of the material for compactio n and for gradation shall be in accordance with
212.21
212.2.5 -Acceptance Plan:
5.1-Compaction: Compaction of random material and select backfill material
shall meet 212.10.
5.2-Gradation: The material shall be sampled and tested in a ccordance with
212.2.3Acceptance for gradation shall be based on test results of consecutive random
samples from a lot. A sublot is the quantity of material represented by a single gradation test as defined in MP 700.00.06. A lot shall be considered t he quantity of material represented by an average test value, not to exceed five sublots. In the case where only one sample is needed for the total plan quantity, this sublot shall be considered the lot. The average shall start on the second sample resul t. The average is continued for the third through fifth sample result, averaging all previous sample results. Thereafter, only the last consecutive five sample results will be averaged (i.e., second test value through sixth test value, third test value t hrough seventh test value, and so forth) as defined in MP 300.00.51. When the average test values of a lot and the test value of the last sublot, or when the last three consecutive individual test values of a lot fall outside the limits specified in 212.2 , the lot of material represented will be considered nonconforming to the extent that the last of its sublots is nonconforming. When this occurs, the last sublot shall have its price adjusted in accordance with 212.2.5.3.
5.3-Degree of Nonconforma nce: When a sublot of material is to have its price
adjusted, the percentage point difference between the nonconforming test value and the specification limit shall be determined for each sieve size determined to be nonconforming, and this value shall be multiplied by its appropriate multiplication factor as set forth in Table 212.2. 5.3 to determine the degree of nonconformance of that sieve.
TABLE 212.2. 5.3 Nonconforming Sieve Size Multiplication Factor 2 in. (50 mm) 1.0 No. 16 1.0
The total measure of nonconformance of an individual sublot is the sum of all nonconformance of an individual sieve sizes of that sublot. When the total degree of nonconformance has been established and it is 12.0 or less, the material will be paid for at an adjusted contract price as specified in Table 212.12.1. When the degree of nonconformance is greater than 12.0, the nonconforming sublot shall be resolved on an individual basis, requiring a special investigation by the Engineer to determine the appropriate cou rse of action to be followed. Pending resolution of the matter, additional lifts of select material for backfill shall not be placed over the nonconforming material.
134 CONSTRUCTION METHODS
212.3 -GENERAL : The foundation pits shall be excavated according to the outlines of footings as shown on the Plans and shall be of sufficient size to permit the placing of the full width and length of the footing. The Engineer may order, in writing, such changes in dimensions or footing elevations as may be necessary to secure a satisfactory foundation. Structural excavation for pipe culverts and underdrains shall be accomplished in accordance with the se ctions covering pipe culverts and underdrains. All foundation excavation adjacent to the tracks of any railroad shall be shored, braced and supported as required by the railroad company or the Engineer, and the Contractor will be held responsible for secu ring such information and complying. Plans for this shoring, bracing, and supporting shall be submitted to and shall meet with the approval of the Chief Engineer of the railway company before starting excavation. Bracing, shoring, and supporting excavati on at structures other than railroad tracks shall meet with the approval of the Engineer.
212.4 -DISPOSAL OF MATERIAL : The excavated material, unless otherwise directed by the Engineer , shall be utilized for backfill or embankments. Surplus material shall be disposed of in such a manner that the efficiency or appearance of the structure shall not be impaired, and the stream not muddied or obstructed.
212.5 -COFFERDAMS : The term cofferdam designates any barrier system that provides a dry, watertight as practicable, area for excavation, inspection or placing concrete. Subject to other requirements in these Specifications, a co fferdam may be constructed of materials including sheet piling, wood, sand bags, earth embankment, etc. or a combination of any of these. Cofferdams shall, in general, be carried well below the bottom of the footings and shall be well braced and as watert ight as practicable. The interior dimensions of cofferdams shall be sufficient to give adequate clearance for the construction of forms and to permit pumping from outside of the forms. When sandy or porous material is encountered in the foundation which renders it impracticable to dewater the excavation before placing masonry, the bottom may be sealed with concrete placed by the tremie method, after which the remainder of the work shall be carried on in the dry. No bracing of any kind shall be left in co fferdams in such a way as to extend in to the substructure masonry without the written permission of the Engineer. Cofferdams shall be removed by the Contractor upon completion of the substructure.
212.6 -PUMPING : Pumping from the interior of any foundation enclosure shall be done in such a manner as to preclude the possibility of the passage of water through fresh concrete. No pumping will be permitted during the placing of concrete, or for a per iod of at least 24 hours, unless it is done with a suitable pump separated from the concrete by a water -tight wall.
212.7-INSPECTION : After an excavation is completed, the Contractor shall noti fy the Engineer, and no footing, pipe, or other structure shall be placed until the Engineer has approved the depth of excavation, the character of foundation material encountered, and has obtained the necessary foundation measurements.