Div35.pdf

Lower Rio Grande Flood Control Project North Banker Floodway Levee Improvements Project Hidalgo County, Texas

DIVISION 35-

USIBWC Contract No.: IBM09B0002 WATERWAY / MARINE

US INTERNATIONAL BOUNDARY & WATER COMMISSION

GOVERNING TECHNICAL SPECIFICATIONS AND PROVISIONS

DIVISION 35 – WATERWAY / MARINE

DIVISION 35-

USIBWC Contract No.: IBM09B0002 WATERWAY / MARINE

This Page Intentionally Blank

LEVEE CONSTRUCTION

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 1 4287-06

Section 35 41 00

PART 1 GENERAL

1.01 SECTION INCLUDES

A. The work covered by this Section consists of furnishing all equipment, labor, materials, and incidentals, and performing all operations necessary for the clearing, grubbing, and stripping of the areas specified herein or indicated on the Drawings, and for the removal and disposal of cleared, grubbed, and stripped materials, removal or plugging of existing drainage structures, and refilling of holes resulting from grubbing; excavation of borrow areas and existing levees, and for all other excavations incidental to the construction of levees, channels, ditches, structures, and ponding areas as specified and shown;

foundation preparation and the construction of levee embankments, including new levee, enlargement of existing levee, backfill of inspection trenches, cutoff trenches, berms, road crossings, backfill at drainage structures, and other incidental earthwork as may be necessary to complete the levee as specified herein and as shown on the Drawings.

1.02 MEASUREMENT AND PAYMENT

A. Unit Prices.

1. No separate payment will be made for Levee Construction under this Section. Include payment in unit prices for various component items required to construct levees.

2. Refer to Section 01 27 00 - Measurement and Payment for unit price procedures.

B. Reserved.

1.03 REFERENCES

A. ASTM C 33 - Standard Specification for Concrete Aggregates.

B. ASTM D 1556 - Density and Unit Weight of Soil in Place by the Sand-Cone Method.

C. ASTM D 1557 - Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort.

D. ASTM D 2167 - Density and Unit Weight of Soil in Place by the Rubber Balloon Method.

E. ASTM D 2216 - Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass.

F. ASTM D 2487 - Soils for CORing Purposes (Unified Soil Classification System).

G. ASTM D 2922 - Density of Soil and Soil-Aggregate in Place by Nuclear Methods.

H. ASTM D 2937 - Density of Soil in Place by the Drive-Cylinder Method.

I. ASTM D 3017 - Water Content of Soil and Rock in Place by Nuclear Methods.

J. ASTM D 422 - Particle-Size Analysis of Soils.

K. ASTM D 4253 - Maximum Index Density and Unit Weight of Soils Using a Vibratory Table.

L. ASTM D 4254 - Minimum Index Density and Unit Weight of Soils and Calculation of Relative Density.

M. ASTM D 4318 - Liquid Limit, Plastic Limit, and Plasticity Index of Soils.

N. ASTM D 4643 - Determination of Water.

O. ASTM D 5195 - Density of Soil and Rock In-Place at Depths Below the Surface by Nuclear Methods.

P. ASTM D 698 - Laboratory Compaction Characteristics of Soil Using Standard Effort.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 2 4287-06

1.05 DEFINITIONS

A. Clearing and Grubbing. Clearing and grubbing shall consist of the removal and satisfactory disposal of materials in accordance with Sections 31 23 30 – Clearing and Grubbing and 01 57 00 - Temporary Erosion, Sedimentation and Environmental Controls.

B. Stripping. Stripping shall consist of the removal and satisfactory disposal of crops, weeds, grass, caliche, and other vegetative materials to the ground surface and stockpiling of topsoil to a specified depth. Stripping shall be in accordance with Section 31 10 00 – Preparing Right-Of-Way.

C. Satisfactory Materials. Satisfactory materials shall consist of materials classified in accordance with

ASTM D 2487 as CL, CL-ML, free from: roots and other organic matter; contamination from hazardous, toxic or radiological substances; trash, debris; and frozen materials. Not all satisfactory materials can be used in levee. Only the satisfactory materials stated above, meeting the additional or modified requirements of paragraph Types of Fill Materials may be used for levee construction.

D. Unsatisfactory Materials. Unsatisfactory materials shall not be used in any levee or other required fill.

Unsatisfactory materials include all other materials that are not defined above as satisfactory materials.

E. Embankment. The terms "levee" or "embankment" as used in these specifications are defined as the earth fill portions of the levee structure or other fills related to the levee structure, including cut-off trench, key-in sections and includes all types of earth fill for the levee and all other fills within the limits of the levee, excepting those stone and filter materials used for slope protection, which are described separately. Complete requirements of embankment are contained in Section 31 33 00 – Embankment.

F. Excavation and Backfill. Excavation shall consist of removal of material to the lines and grades shown on the Drawings, or as otherwise directed or compliance-confirmed by the COR. Backfill as used in this Section is defined as that fill material that cannot be placed around or adjacent to a structure or utility until the structure or utility is completed, or until a specified time interval has elapsed after completion. Complete requirements of backfill are contained in Sections 31 31 60 - Excavation and Backfill for Materials and 31 31 70 – Excavation and Backfill for Utilities .

G. Classification of Soils. Materials used to construct the embankments and for backfills shall be classified in accordance with ASTM D 2487 (Unified Soil Classification System). Cohesionless materials shall include materials classified in ASTM D 2487 as GW, GP, SW, and SP. Cohesive materials include materials classified as GC, SC, ML, CL, MH, and CH. Materials classified as GM and SM will be identified as cohesionless only when the fines are nonplastic.

H. Degree of Compaction.

1.. Cohesive Material. Degree of compaction shall be expressed as a percentage of the maximum density obtained by the test procedure presented in either ASTM D 698 or ASTM D 1557, abbreviated hereinafter as percent laboratory maximum density.

2.. Cohesionless Material. Degree of compaction shall be expressed as a percentage of the relative density in accordance with ASTM D 4253 and ASTM D 4254.

1.04 SUBMITTALS

A. Submittals shall conform to requirements of Section 01 33 00 - Submittal Procedures.

B. Shoring, Sheeting, and Bracing. Submit a detailed shoring, sheeting and bracing plan 30 days prior to the beginning of any excavation requiring its use. The plan for shoring, sheeting and bracing shall be prepared by a Texas licensed professional COR. The plan shall include drawings and design computations of the proposed shoring, sheeting, and bracing, and documentation, showing details of the coordination and compliance-confirmation of shoring, sheeting, and bracing. Compliance-confirmation of the detailed plan shall be obtained from the Government prior to starting the work. If necessary, the plan shall be modified as required to meet field conditions, and the modifications shall be compliance-confirmed by the Government prior to use.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 3 4287-06

C. Excavation. Submit a written excavation plan 30 days prior to the beginning of any excavation.

Compliance-confirmation of the detailed plan shall be obtained from the Government prior to starting the work. If necessary, the plan shall be modified as required to meet field conditions, and the modifications shall be compliance-confirmed by the Government prior to use. As a minimum, the plan shall contain the following:

1. Proposed methods for preventing interference with, or damage to, existing underground or overhead utility lines, trees designated to remain and other man-made facilities or natural features designated to remain within or adjacent to the construction rights-of-way.

2.. Provision for coordinating the work with other Contractors working in the construction rights-of-way or on facilities crossing or adjacent to this work.

3.. The proposed methods for controlling surface and ground water in the borrow areas and required excavations in accordance with Section 01 57 80 – Control of Ground Water and Surface Water.

4. Stockpiling plan for embankment material before it is transported to the project site showing locations, stockpile heights, slopes, limits, and drainage around the stockpile areas.

5. The Contractor's proposed sequence of work for excavating the borrow areas with plan and cross sectional views showing starting and final work locations and clearing, grubbing and stripping limits.

6. The Contractor's proposals for conserving arable land and for making optimum use of available borrow, including the Contractor's proposed methods for grading the bottom of the borrow areas after completing use of the borrow areas.

7. The Contractor's proposed road pattern, and plan for implementing dust control measures in accordance with Section 01 57 20 – Source Controls for Erosion and Sedimentation.

D. Borrow areas. Borrow areas shall be in accordance with Section 31 31 90 – Borrow.

1. Haul Roads. Haul roads shall be constructed and maintained by the Contractor as necessary to perform the Work. Thirty (30) days prior to commencement of haul road construction or placing embankment and backfill which ever is earlier, Contractor shall submit for compliance-confirmation a Plan of Operations for accomplishing all embankment and backfill construction and for the location and construction of haul roads. This plan shall include, but not be limited to, the Contractor's proposed sequence of construction for embankment and backfill items, and methods and types of equipment to be utilized for all embankment and backfill operations, including transporting, placing, and compaction. This plan shall also include the names and addresses of the firms that will perform the soil testing and inspection and describe how all required soils testing will be performed in accordance with the applicable Sections.

E. Embankment and Backfill Materials. At least 30 days prior to delivery of any material to the site of the work, the Contractor shall submit soil classification test results, moisture-density curves, gradation curves, and laboratory results of the required tests of the proposed material.

F. Filter Sand. At least 30 days prior to delivery of any material to the site of the work, the Contractor shall submit soil classification test results and a gradation curve for each of the proposed filter materials to be used.

G. Nuclear Density. Nuclear density testing equipment shall be used in accordance with ASTM D 2922 and ASTM D 3017. In addition, the following condition shall apply:

1. Prior to using the nuclear density testing equipment on the site, the Contractor shall submit to the COR a certification that the operator has completed a training course compliance-confirmed by the nuclear density testing equipment manufacturer. In addition, the Contractor shall also submit the most recent data sheet from the manufacturer's calibration, and a copy of the most recent statistical check of the standard count precision.

2. The nuclear density testing equipment shall be capable of extending a probe a minimum of 6 inches down into a hole.

H. Test Reports. Submit a copy of the records of each compliance survey the next work day following the survey.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 4 4287-06

1.05 GENERAL PROJECT CONDITIONS

A. Lines and Grades. The levee shall be constructed to the lines, grades, and cross sections indicated on the Drawings, unless otherwise directed by the COR. The Government reserves the right to increase or decrease the foundation widths and embankment slopes or to make such other changes in the embankment or backfill sections as may be deemed necessary to produce a safe structure.

Changes in quantities resulting from such revisions will not constitute justification for change in contract unit prices, except as provided for in the Standard General Conditions of the Construction Contract. Increases in height of section, made to compensate for settlement or consolidation of the embankment material subsequent to the completion of the embankment, will not exceed 1 percent of the height above the foundation at the levee centerline indicated. The end slopes and side slopes of partial fill sections shall not be steeper than that shown on the Drawings.

B. Conduct of the Work. The Contractor shall maintain and protect the embankment and backfill in a satisfactory condition at all times until final completion and acceptance of all work under the Contract.

If, in the opinion of the Government, the hauling equipment causes horizontal shear planes or slicken sides, rutting, quaking, heaving, cracking, or excessive deformation of the embankment or backfill, the Contractor shall limit the type, load, or travel speed of the hauling equipment on the embankment or backfill. The Contractor may be required to remove, at his own expense, any embankment material placed outside of prescribed slope lines. Any compliance-confirmed embankment or backfill material which is lost in transit or rendered unsuitable after being placed in the embankment or backfill and before final acceptance of the work shall be replaced by the Contractor in a satisfactory manner and no additional payment will be made therefor. The Contractor shall excavate and remove from the embankment or backfill any material that is unsatisfactory and shall also dispose of such material and refill the excavated area as directed, all at no cost to the Government.

C. Embankment and Backfill Materials. Materials for embankment and backfill construction will be obtained from sources provided by the Government and/or the Contractor. Materials obtained from required excavation which meet or which can be processed to meet the requirements of the various Sections of the Contract documents, or any other material required for this project, as specified herein, may be utilized in the appropriate zone of the embankment or as backfill. All roots, limbs, and wood fragments shall be removed from embankment materials. Materials containing sod, other organic or perishable material, trash, debris, and frozen materials shall not be used in the embankment. The Contractor shall submit to the COR the source or sources from which he intends to obtain materials for embankment construction. If a source is selected other than a commercial quarry or other commercial entity from which earth or rock material will be directly purchased and where the Contractor or his subcontractor will perform the borrow excavation, a written statement shall be provided to the Government indicating permission to utilize the area. It shall be the responsibility of the Contractor to obtain Federal, State, and local permits which may be required for excavation and reclamation of the borrow area. A copy of the plan and procedures to be utilized for reclamation shall be furnished to the Government. The Government will require material samples from any proposed borrow source to be submitted as indicated in paragraph Quality Control.

D. Haul Roads. Haul roads shall be located and constructed as compliance-confirmed by the

Government. Prior to the commencement of construction, the Contractor shall submit for compliance-confirmation a site plan detailing the location of all haul roads within the project limits. Haul road(s) between the borrow site(s) and the levee embankment shall be located within the limits compliance-confirmed by the Government. The limits of the borrow haul road shall be clearly marked in the field using construction fencing or similar methods compliance-confirmed by the COR. Areas on each side of the borrow haul road corridor shall not be disturbed. Haul roads shall be constructed to maintain the intended traffic, be free draining, and be maintained in good condition throughout the Contract period. Any haul road that crosses any creek or drainage facility shall be constructed, and maintained by the Contractor so as to not flood either upstream areas by restricting stream flows or flood downstream areas by the release of any stored water in the event that the crossing fails for any cause.

Haul roads constructed during the Contract duration shall be removed after work is final accepted and the impacted area restored to its preconstruction conditions. The Contractor shall plow and/or scarify or otherwise loosen all access and haul roads other than existing roads to a minimum of 6 inches

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 5 4287-06 deep and the surface shall be left in a smooth condition. All haul roads within the right-of-way that will remain as public thoroughfares after construction shall be cleaned daily and maintained in the preconstruction condition. All costs associated with these haul roads shall be considered as a subsidiary obligation of the Contractor.

E. Ramps/Levee Access and Crossings. Ramps/Levee Access and Crossings shall be constructed at the locations shown on the Drawings by placement of a fill as specified herein. Ramps/Levee Access and Crossings shall be constructed only by adding material to the levee crown and slopes.

Ramps/Levee Access and Crossings shall have width, grade, and side slopes as shown on the Drawings.

F. Runways. Where material is hauled over an existing levee for construction, the Contractor, at his expense, will be permitted to construct temporary runways over the levee by the addition of material to the levee cross section. For the construction of runways, the existing levee may not be cut. Minimum width of haul roads shall be 25 feet for one-way traffic, and 50 feet for two-way traffic. Runways into the existing levee may be constructed at intervals of less than 500 linear feet for the 25-foot bottom widths or less than 1,000 linear feet for the 60-foot bottom. The Contractor shall stockpile, as directed by the COR, sufficient suitable levee embankment material to construct emergency closure of any cuts.

G. Closure of Runways. Where runways have been cut through the levee, the Government reserves the right to order their closure at no additional cost to the Government at any time that such runways may endanger the security of the levee. Just prior to restoration of the runway, the bottom of any cut made in the levee shall be broken to a depth of 6 inches and the side slopes thoroughly scarified. The restoration shall be made with suitable embankment material, placed and compacted as provided in other Sections. Material used in the construction of the approach ramps of the runways shall be removed and may be used for fill, if satisfactory. If not used for fill, the material may be disposed of by placing it in abandoned portions of the borrow areas or by any other method specified in SPECIFICATION 01 57 00 – Temporary Erosion, Sedimentation and Environmental Controls. No section of the levee shall be degraded or weakened to provide runways nor shall existing runways remain open during extended non-work periods, unless otherwise compliance-confirmed in writing by the Government.

H. Stockpiling. Any on-site stockpiling of embankment materials shall be in accordance with paragraph

Stockpiles.

I. Slides and Foundation Failures. When sliding occurs in any part of the embankment and backfills prescribed in this Section after they have been placed, but prior to final acceptance of all work under the Contract, the Contractor shall repair the slide as directed by the COR. When the slide is caused through the fault of the Contractor, the repair shall be made at no cost to the Government. When the slide is not the fault of the Contractor, an equitable adjustment in the contract price shall be made pursuant to the Standard General Conditions of the Construction Contract to cover the cost of the repairs.

J. Drainage Requirements. The Contractor shall not block or restrict the flow in a natural drain, existing culvert, ditch or channel at any time without obtaining prior written compliance-confirmation from the Government. This compliance-confirmation shall not relieve the Contractor from responsibility for any damage caused by his operation. The Contractor shall monitor drainage flows and provide sufficient free discharge areas so that conditions are not worsened upstream or downstream by possible floods during construction. Surface water shall be directed away from excavations and construction sites so as to prevent erosion and undermining of foundations. Diversion ditches, dikes, and grading shall be provided and maintained as necessary during construction. Excavated slopes and backfill surfaces shall be protected to prevent erosion and sloughing. Excavation shall be performed so that the site and the area immediately surrounding the site and affecting operations at the site shall be continually and effectively drained. If private property is to be used for drainage, submit written evidence that the right has been obtained from the property Government for drainage on his property.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 6 4287-06

1.07 PROJECT SITE CONDITIONS

A. Protection of Man-Made Facilities and Natural Features. Trees within the work area shall be felled in such a manner as to avoid damage to trees left standing and trees outside the clearing area, existing buildings, man-made facilities and natural features, with due regard to the safety of employees and others. Excavation shall follow the same requirements specified above for felling trees and shall be in compliance with Sections 31 31 60 – Excavation and Backfill for Structures and 31 31 70 – Excavation and Backfill for Utilities. Existing utility lines that are shown on the Drawings or the locations of which are made known to the Contractor prior to excavation and that are to be retained shall be protected from damage. When utility lines that are to be removed are encountered within the area of operations, the Contractor shall notify the applicable utility companies in sufficient time for measures to be taken to prevent interruption of the services.

B. Historical, Archeological, and Cultural Resources. Historical, archeological, and cultural resources within the project work limits may exist. If, during construction activities, the Contractor observes items that may have historical or archeological value, such observations shall be reported immediately to the COR so that appropriate authorities may be notified and a determination made as to their significance and what, if any, special disposition of the finds should be made. The Contractor shall cease all activities that may result in the destruction of these resources and shall prevent his employees from trespassing on or otherwise damaging such resources.

C. Subsurface Data. Subsurface soil boring locations are shown on the drawings. These data represent subsurface information at the boring locations; however, variations may exist in the subsurface between boring locations. Groundwater levels indicated on the soil boring logs were levels found at the time of exploration. The groundwater table can vary significantly depending on time of year, variation from normal precipitation, and river stage or tide level.

1.08 SEQUENCE OF WORK

A. Preparing Right of Way / Clearing and Grubbing. Preparing right of way and clearing and grubbing in accordance with section 31 10 00 shall be completed at least 300 feet in advance of embankment construction. In locations where work on drainage structures is performed prior to embankment construction, all clearing and grubbing shall be completed for the structure. If regrowth of vegetation or trees occurs after clearing and grubbing and before placement of embankment, the Contractor will be required to clear and grub again prior to embankment construction.

B. Stripping. After inspection and acceptance of cleared and grubbed areas, stripping may proceed. All stripping work shall be completed not more than 300 feet in advance of embankment construction.

PART 2 PRODUCTS

2.01 TYPES OF FILL MATERIALS

A. Select Fill. Select fill embankment material shall be obtained from sources secured by the Contractor.

The select fill material shall consist of satisfactory materials classified in accordance with ASTM D 2487 as CL, SC, or GC.

B. Impervious Fill. This material shall consist of satisfactory impervious material classified as lean clay

(CL), low plasticity silt (ML), sand containing more than 30 percent of clay (CL), and borderline clay and silt (CL-ML) in accordance with ASTM D 2487. Impervious Fill material shall not be compacted using vibratory rollers.

C. Pervious Fill. This material shall consist of satisfactory pervious material classified as well graded sand (SW), poorly graded sand (SP) in accordance with ASTM D 2487.

D. Coarse Drainage Gravel. Coarse gravel material for toe drains shall be obtained from a source provided by the Contractor. Coarse drainage gravel shall be non-calcareous, composed of tough durable particles, and shall not contain any organic material or soft, friable particles in quantities.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 7 4287-06

Blast furnace slag will not be permitted. The gravel material in-place shall meet the requirements of AASHTO M 43, Size No. 57, with the following gradation:

SIEVE SIZE

U.S. STANDARD

SQUARE MESH

PERCENTAGE BY

WEIGHT PASSING

INDIVIDUAL SIEVE

1” – 1/2" 100 1” 95 – 100

1/2" 25 – 60 No. 4 0 – 10 No. 8 0 - 5

E. Fine Drainage Gravel. Fine drainage gravel shall be obtained from a source secured by the

Contractor. Fine drainage gravel material shall be non-calcareous, composed of tough durable particles, and shall not contain organic material. The fine drainage gravel in-place shall meet the requirements of AASHTO M 43, Size No. 8, with the following gradation:

SIEVE SIZE

U.S. STANDARD

SQUARE MESH

PERCENTAGE BY

WEIGHT PASSING

INDIVIDUAL SIEVE

1/2" 100 3/8” 85 – 100

No. 4 10 – 30 No. 8 0 – 10 No. 16 0 – 5

F. Topsoil. Topsoil shall be in accordance with Section 31 91 10 – Topsoil.

2.03 RIPRAP

A. Riprap shall be in accordance with Section 31 33 10 - Riprap.

PART 3 EXECUTION

3.01 CLEARING

A. Clearing shall be accomplished within the limits of existing ground to receive embankment and structures, together with strips 5 feet wide, beyond and contiguous thereto, existing levees to be degraded, ponding areas, ditches, structures, traverses, channels, riprap, revetment, borrow areas and ramps. Trees, downed timber, snags, slash, brush, garbage, trash, debris, fencing and other items shall be cleared in accordance with Section 31 23 30 – Clearing and Grubbing. Trees and vegetation designated to be left standing or to remain shall be protected from damage from construction operations. Clearing of borrow areas shall be limited to the minimum area required for construction operations.

3.02 GRUBBING

A. Grubbing shall be accomplished within the limits of existing ground to receive embankment and structures, together with strips 5 feet wide, beyond and contiguous thereto, existing levees to be degraded, ponding areas, ditches, structures, traverses, channels, riprap, revetment, borrow areas and ramps. Grubbing shall be accomplished in accordance with Section 31 23 30 – Clearing and Grubbing.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 8 4287-06

3.03 STRIPPING

A. The entire area within the limits of existing ground to receive embankment and structures, together with strips 5 feet wide, beyond and contiguous thereto, existing levees to be degraded, ponding areas, and ditches shall be stripped to remove crops, weeds, grass, and other vegetative materials to the ground surface and topsoil to a depth of 4 inches.

3.04 DISPOSITION OF CLEARED, GRUBBED, AND STRIPPED MATERIAL

A. All materials resulting from clearing and grubbing operations shall be disposed of in accordance with SPECIFICATION 01 57 00 – Temporary Erosion, Sedimentation and Environmental Controls.

3.05 SHORING, SHEETING, AND BRACING

A. Shoring, sheeting, and bracing shall be installed where required for the protection of existing natural features and man-made facilities, for the safety of workers and the public, and to insure the integrity of the embankment. Shoring, sheeting and bracing shall not be used in lieu of the required excavation slopes. Shoring, sheeting, and bracing shall be adequately designed and properly installed to withstand anticipated loads. Shoring, sheeting and bracing shall be planned and designed by a registered professional COR. The Contractor shall submit a plan for shoring, sheeting, and bracing in accordance with paragraph SUBMITTALS. All shoring, sheeting and bracing shall be removed as embankment and backfill operations progress.

3.06 DEWATERING AND DIVERSION

A. Surface and groundwater control shall be accomplished in coordination with the required excavation, embankment construction, and in accordance with Section 01 57 80 – Control of Ground Water and Surface Water.

3.07 EXCAVATION

A. Excavation shall consist of removal of material in preparing the foundations to the lines and grades shown on the Drawings, removal of material from ditches and channels to the lines and grades shown on the Drawings, removal of objectionable materials and obtaining required fill materials from the borrow areas. Blasting will not be permitted. Over excavation shall be backfilled to grade with similar over excavated material or satisfactory material and compacted to a density of at least that of the surrounding material.

a. Over excavation Outside Limits of Levee Foundations or Structures. Over excavation outside the limits of the foundations of levees or structures shall be backfilled to grade with similar over excavated material or satisfactory material and compacted to a density of at least that of the surrounding material.

b. Over excavation Within Limits of Levee Foundations or Structures. Over excavation within the limits of the foundations of levees or structures shall be backfilled to grade in accordance with paragraph PREPARATION OF FOUNDATION, PARTIAL FILL SURFACES AND

ABUTMENTS.

B. Structures. Excavations for structures shall conform to Section 31 31 60 – Excavation and Backfill for

Structures and the dimensions and elevations indicated for each structure and footing, except as specified hereinafter, and shall include trenching for utility and foundation drainage systems to a point 3 feet beyond each structure and all work incidental thereto. Excavation shall extend a sufficient distance from walls and footings to allow for placing and removal of forms. Satisfactory material removed below the depths indicated without specific direction of the COR shall be replaced at no additional cost to the Government and filled in accordance with paragraph Over Excavation above.

Over excavation below required invert elevations or bottoms of footings shall be backfilled with lean concrete at no additional cost to the Government. No footings shall be constructed on unsatisfactory material as determined by the COR. Excessively wet and/or soft material in subgrades resulting from water ponding in footing excavations shall be removed and replaced with lean concrete.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 9 4287-06

C. Slopes and Surcharges. Temporary excavation slopes for any channel, structure excavation, or other required excavation shall not be steeper than the specified finished slope or the specified construction slope, as applicable, and subject to the compliance-confirmation of the COR. This may be accomplished by benching the temporary slope so that the average slope is not steeper than the specified slope. In addition, no temporary, permanent, or construction slope shall be surcharged with excavated or stockpiled material or with heavy construction equipment which would have the same effect as the surcharge material. The toe of stockpiled material shall be maintained a minimum distance back from the top of the finished excavation equal to the depth of the excavation. The maximum height of such stockpile without causing instability of the excavation slope shall be determined by the Contractor. Any slide or other adverse conditions caused by failure of the Contractor to maintain these conditions shall be considered the responsibility of the Contractor and remedial measures shall be at the Contractor's expense.

3.08 BORROW AREAS

A. Borrow areas proposed by the Contractor shall be subject to Section 31 31 90 - Borrow and compliance-confirmation by the Government. Any borrow sources proposed, accepted, and compliance-confirmed by the Government shall meet all applicable requirements.

B. Cut-Off Trenches. A cutoff trench shall be excavated and maintained free of standing water. The trench shall be excavated at least 50 feet in advance of but not more than 200 feet of construction.

C. Existing Levees and Spoil Banks. Existing levees and spoil banks shall be removed as shown on the Drawings. In areas where the existing levee is located within the random or berm zone of the levee, it shall be incorporated into the embankment. Portions of existing embankments which lie within the impervious zone of the levee shall be removed. Existing levees located within the rights-of-way landward of the levee and berms to be constructed, may be utilized as borrow material, but only after equal protection has been provided by construction of the new levee. When excavated for borrow material, the existing levee shall be removed to the adjacent ground surface in a uniform manner, and shaped to maintain drainage in accordance with the adjacent natural drainage pattern. When lower levels of flood protection would be caused by levee construction, the Contractor shall provide the Government a plan to maintain existing levels of protection during the construction period.

D. Toe Drains. Toe drains shall be excavated to the dimensions and the locations indicated on the

Drawings.

E. Utilities. Excavations for pipe beds shall be shaped to fit the contour of the pipe over a width of not less than 0.6 of the pipe diameter, or as shown on the Drawings.

F. Rock. Rock and other hard foundation materials shall be cleaned of loose debris and cut to a firm surface, either level, stepped, or serrated, as shown on the Drawings. Loose disintegrated rock and thin strata shall be removed. Rock excavation will not be measured for payment. Rock excavation will not be paid for as a separate bid item.

G. Riprap and Bedding. Excavations for riprap and bedding shall be performed at the locations and to the lines and grades shown.

3.09 TOLERANCES

A. A tolerance of 3 inches above or below the prescribed grade will be allowed in the excavation for channels, ditches, inspection trenches, cutoff trenches, excavations for riprap and bedding, and mandatory borrow areas. A tolerance of 4 inches below the prescribed grade will be allowed in the excavation for all other borrow areas.

B. All embankments and backfills shall be constructed to the grades, lines, and cross-sections shown on the Drawings. At all points a tolerance of 4 inches above the prescribed grade will be permitted in the final dressing, provided that any excess material is so distributed that the crown of the levee drains and that there are no abrupt humps or depressions in any surfaces. For topsoil, a tolerance of 3 inches above the thickness as shown on the Drawings will be permitted.

3.10 SLIDES

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 10 4287-06

A. In case sliding occurs in any part of the excavations prescribed in this Section after they have been excavated, but prior to final acceptance of all work under the Contract, the Contractor shall repair the slide as directed by the COR. In case the slide is caused through the fault of the Contractor, it shall be repaired at no cost to the Government. In case the slide is due to no fault of the Contractor, an equitable adjustment in the Contract price will be made for the repairs in accordance with the Standard General Conditions of the Construction Contract.

3.11 TRAVERSES

A. Traverses shall be left unexcavated between borrow areas at the locations and to the cross sections shown on the Drawings.

3.12 STOCKPILES

A. Provisions of paragraph Slopes and Surcharges are applicable to all stockpiled materials. Upon completion of construction operations, all remaining stockpiled material shall be removed and disposed of by the disposal methods specified in paragraph Disposition of Excavated Materials.

3.13 SURFACE DRAINAGE OF COMPLETED AREAS

A. The areas shown on the drawings designated as "GRADE TO DRAIN", the borrow areas, and the finished embankment areas shall be graded to the lines and grades shown on the Drawings. The surface shall be free from sharp ridges, gullies, potholes, sinkholes, and any other surface irregularities. A tolerance of 2 inches above or below the prescribed grade will be allowed provided that the surface drains in the direction as indicated on the Drawings.

3.14 MAINTENANCE OF WORK

A. Debris Removal. The Contractor shall maintain all ditch and channel excavations free from leaves, brush, sticks, trash, and other debris until final acceptance of all work under the Contract at no additional cost to the Government.

B. Sediment Removal. Prior to final acceptance of all work under this Contract, the removal of sediments from ditch or channel excavations shall be required to restore design grade and section at no additional cost to the Government.

3.15 DISPOSITION OF EXCAVATED MATERIALS

A. Satisfactory Materials. Satisfactory excavated material shall be incorporated in the appropriate zones of the embankment. Satisfactory material shall consist of material as defined in paragraph Definitions, subparagraph Satisfactory Materials. When direct placement is not practicable, satisfactory material from the excavation may be stockpiled for subsequent use in parts of the work for which it is specified herein and/or as indicated on the Drawings. Satisfactory materials in excess of the quantity necessary to construct backfills and embankments shall be disposed of as specified in SPECIFICATION 01 57 00 – Temporary Erosion, Sedimentation and Environmental Controls.

B. Unsatisfactory Materials. Unsatisfactory materials shall be as defined in paragraph Definitions, subparagraph Unsatisfactory Materials. Unsatisfactory materials from the excavations prescribed in this Section shall be permanently disposed of in accordance with SPECIFICATION 01 57 00 – Temporary Erosion, Sedimentation and Environmental Controls.

3.16 PREPARATION OF FOUNDATION, PARTIAL FILL STRUCTURES, AND ABUTMENTS

A. Earth. After excavation (as described in paragraph Excavation) or stripping (as described in paragraph Clearing, Grubbing and Stripping) of the embankment foundation to the extent indicated or otherwise required, the sides of stump holes, test pits, and other similar cavities or depressions shall be broken down so as to flatten out the slopes, and the sides of the cut or hole shall be scarified to provide bond between the foundation material and the fill. Unless otherwise directed by the COR, each depression shall be filled with the same material type that is to be placed immediately above the

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 11 4287-06 foundation. The fill shall be placed in layers, moistened, and compacted in accordance with the applicable provisions of paragraphs Placement, Moisture Control, and Compaction for the specific material type. Materials which cannot be compacted by roller equipment because of inadequate clearances shall be compacted with power tampers in accordance with the paragraph Compaction for the specific material type. After filling of depressions and immediately prior to placement of compacted fill in any section of the embankment, the foundation of such section shall be loosened thoroughly by scarifying, plowing, discing or harrowing to a minimum depth of 6 inches, and the moisture content shall be adjusted to the amount specified in paragraph Moisture Control for the appropriate type of material. After removal of roots or other debris turned up in the process of loosening, the entire surface of the embankment foundation area shall be compacted as specified for the appropriate type of fill. Immediately prior to placement of compacted fill on or against the surfaces of any partial fill section, all soft or loose material, all material containing cracks or gullies, and all material that does not conform with the specified zoning of the embankment shall be removed. The remaining surface of the partial fill shall be loosened by scarifying, plowing, discing or harrowing to a minimum depth of 6 inches, and the moisture content shall be adjusted as specified in paragraph Moisture Control for the appropriate type of material. The surface of the partial fill section upon which fill is to be placed shall then be compacted as hereinafter specified for the appropriate type of fill. No separate payment will be made for loosening and rolling the foundation area, the abutment area, or the surfaces of partial fill sections, but the entire cost thereof shall be included in the applicable Contract price for fill.

B. Rock Foundation. All rock surfaces upon which or against which embankment materials are to be placed shall be excavated (as described in paragraph Excavation or stripped (as described in paragraph Clearing, Grubbing and stripping). Prior to the placement of embankment material upon or against a rock surface, all open joints and cracks in that surface shall be filled with mortar to the depths cleaned. Those portions of such rock surfaces where, in the opinion of the COR, the compaction of the embankment materials cannot be accomplished satisfactorily with power tampers or other specified compaction equipment shall be filled with mortar or concrete as directed to the extent necessary to permit satisfactory use of the compaction equipment. In no case shall a thin coat of mortar be left on smooth, intact rock surfaces. Large rock overhangs and protrusions shall be removed and rock surfaces shall be laid back to a slope no steeper than 4V on 1H by the use of pre-splitting or line drilling techniques in such a manner as to minimize damage to the underlying rock, or the spaces beneath overhangs and around protrusions shall be filled with tamped concrete so that satisfactory compaction of embankment materials can be accomplished. Rock surfaces shall not be more than 2 feet in height, and benches of sufficient width shall be provided as necessary.

C. Benching. Benching into existing levee embankment and abutments is required in order to place and compact the material in horizontal layers. The vertical face cut into the existing embankment or abutment resulting from the benching operation shall be a minimum of 6 inches in height but shall not exceed 12 inches in height.

D. Preloading. Preloading of the levee foundation will not be required.

E. Settlement of Foundation. The Contractor shall, at his expense, furnish and install settlement gages for determination of settlement of the foundation during construction. Settlement measurements will be subject to verification by the Government.

3.17 TEST FILL STRIPS

A. General. Before beginning embankment construction, the Contractor shall construct test strip(s) for embankment fill materials to demonstrate that the equipment and compaction procedure will achieve the moisture-dry density relationship as specified. The test strips shall be constructed using materials from the borrow sources which have been provided or compliance-confirmed by the Government. A test strip shall be performed for each type of fill materials. Each test strip shall be of sufficient size to allow compaction equipment to achieve normal operating speed over a 50 foot length. The test strip shall be a minimum of two (2) times wider than the compaction equipment. Each test strip shall be

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 12 4287-06 constructed with a minimum of 4 lifts. Prior to the construction of the test strips, the foundation (subgrade) shall be proof rolled as specified in Texas Department of Transportation Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges Item 216 and an 8 inch thick subbase layer installed. The subbase layer shall consist of the same material to be used in the test strip and shall be spread and compacted to the same requirements. The test strips shall be constructed in accordance with the applicable provisions of paragraphs Placement, Moisture Control, and Compaction for the specific material type.

The fill material shall be placed and spread in layers in accordance with the applicable provisions of paragraphs Placement for the specific material type. Each layer of the fill shall be compacted with a minimum of four (4) complete coverages using the specified compaction equipment, and as many additional coverages as may be required to achieve the specified density. Even if the results from the test strips show that the required densities can be obtained with less than four coverages by the compaction equipment, the Contractor shall still be required to compact the impervious and random fills with a minimum of (4) complete coverages. If the use of the proposed compaction equipment causes shearing of the fill, laminations in the fill, or results in inadequate compaction, the COR may direct that such roller be removed from the fill and that another appropriate tamping roller be used.

B. Testing and Reporting Requirements for Test Strips. Prior to construction of the test strips, the

Contractor shall perform one laboratory compaction test for each type of material used in test strips.

The compaction tests shall be performed in accordance with the requirements specified in paragraph Materials Testing. Test results shall be submitted to the Government before construction of the test strips. After placement and spreading of the fill in the test strip, but prior to compaction, five samples shall be obtained from each lift for moisture content determination in accordance with ASTM D 2216.

After compaction of the fill, a minimum of 5 in-place nuclear density and moisture content tests (in accordance with ASTM D 2922 and ASTM D 3017, respectively) and one (1) sand cone density test (in accordance with ASTM D 1556) shall be performed on each lift. One sample shall be obtained from each test strip for classification testing as specified in paragraph Materials Testing. All testing and sampling locations shall be determined by the COR. The Contractor's personnel shall monitor and document construction and testing of the test strips. Documentation shall include weather conditions, soil type, spreading and compaction equipment type, lift thickness, number of coverages, moisture content, dry density, and a plan showing approximate location of sampling and testing.

Documentation of the test strip construction procedures and results of all testing shall be provided to the Government. Full scale embankment construction shall not commence until the equipment and placement methods are compliance-confirmed by the Government.

3.18 PLACEMENT AND SPREADING

A. General. Prior to beginning embankment placement on the levee foundation, the Contractor shall notify the COR that the foundation is ready to receive fill. No fill shall be placed on any part of the embankment foundation until such areas have been inspected and given final compliance-confirmation by the Government.

B. Gradation and Distribution. The gradation and distribution of materials throughout each zone of the levee shall be such that the embankment will be free from lenses, pockets, streaks, and layers of material differing substantially in texture or gradation from surrounding material of the same class. If lenses, pockets, or layers of materials differing substantially in texture or gradation from surrounding material occur in the spread material, the layer shall be mixed by harrowing or any other compliance-confirmed method to blend the materials. During the placing and spreading process, the Contractor shall maintain at all times a force of workers adequate to remove all roots, debris, and oversize stone from all embankment materials. All stones and rock fragments larger than 3 inches in any dimension shall be removed from the fill. No fill shall be placed upon a frozen surface, nor shall snow, ice, or frozen earth be incorporated in the embankment.

C. Foundations and Partial Embankment Fills. The foundations and all partial embankment receiving fills shall be kept thoroughly drained. Placing operations will be such as to avoid mixing of materials from adjacent sections as much as practicable.

USIBWC Contract No.: IBM09B0002 Page 35.41.00 - 13 4287-06

D. Equipment Traffic. Equipment traffic on any embankment zone shall be routed to distribute the compactive effort as much as practicable. Ruts formed in the surface of any layer of spread material will be filled before that material is compacted. If, in the opinion of the COR, the compacted surface of any layer of material is too smooth to bond properly with the succeeding layer, the surface shall be loosened by scarifying or other compliance-confirmed methods before material from the succeeding layer is placed.

E. Placement of Embankment and Backfill against Rock. In restricted areas where material can not be placed in large lifts with normal spreading and compaction equipment material shall be spread in lifts not exceeding 4 inches and compacted with mechanical hand tampers, vibrating plates, or other compliance-confirmed methods and equipment.

F. Placement of Embankment and Backfill against Structures. No embankment or backfill shall be placed on or against concrete less than 7 days after placement or 70 percent of the design strength, without prior compliance-confirmation of the COR.