section_02001_construction staking.doc

SECTION 02001

CONSTRUCTION STAKING

PART 1 - GENERAL

1.1 DESCRIPTION OF WORK

A. This work shall consist of the construction staking of the project by the methods specified herein, or another acceptable coordinate geometry method. The items to be surveyed and staked include taxi-lanes, aprons, roadways, buildings, loading pads, sidewalks, underground utilities and other related site work AS SHOWN ON THE DRAWINGS, from coordinates and control points AS SHOWN ON THE DRAWINGS. The work includes furnishing all labor, equipment, instruments, stakes, materials, transportation, and other incidentals necessary to complete the construction staking in accordance with these specifications and acceptable engineering practice. The work shall also include setting grade-finishing stakes and/or red and blue tops for paving and concrete forming.

B. Construction staking shall be accomplished under the direction of a Professional Engineer or Land Surveyor registered in the state of the construction project. The Professional Engineer or Land Surveyor will be closely associated and familiar with the construction staking; periodic visits to the project site are required.

PART 2 - MATERIALS

2.1 STAKES

A. All stakes shall have the nominal dimensions listed below. Identification stakes shall be of sufficient length to provide a solid set in the ground and to provide space for marking above ground when applicable. Other dimensions and materials may be used, such as steel reinforcing bars, wire flagging and markers, and metal pins, if approved in writing by the Contracting Officer. The top 2 inches of all slope, guard, reference, clearing, and structure stakes shall be painted or marked with plastic flagging. Colors used on stakes or for flagging shall be as listed below.

B. Stakes shall have the nominal dimensions of 1”x 2”x 18”. Colors for paint and flagging shall be as follows or as agreed to by the Contracting Officer:

Taxi-Lane Centerline

Red

Roadway Centerline

Coordinate Layout Points

Taxi-Lane Centerline Reference Points Red and White

Roadway Centerline Reference Points

Coordinate Layout Reference Points

Temporary Bench Marks

Yellow

Slope Stakes

Orange

Slope Stakes Reference Points

Orange and White

Drainage Structures

Blue

Drainage Structures Reference Points Blue and White

Clearing Limits

Yellow

Cross-Section Alignment

Orange wire flag

2.2 SUBMITTALS

A. Paper for survey notes shall be moisture resistant paper. All notes shall become the property of the Government. Submit notes contained in books with covers that will protect the contents and retain the pages in numerical sequence during field use. The Contractor shall furnish field notebooks and note paper. The field books used shall include notes for this project only. If the field data is collected electronically, field books shall be submitted as described in 3.1.C.

B. Upon completion of a portion of any staking involving grading, a cut sheet shall be prepared showing, at a minimum, point number or station, offset (if any) stake elevation, proposed grade and cut or fill. The Contractor shall submit one (1) copy of the cut sheets to the Contracting Officer in addition to any copies required by the Contractor's work crews.

C. At the conclusion of construction, a set of construction drawings reflecting the actual locations and elevations of all contract features, as constructed, shall be submitted to the Contracting Officer.

2.3 GOVERNMENT FURNISHED DOCUMENTS

A. The Contractor shall be furnished drawings, location, coordinates and elevations of control points. All documents shall be returned to the Contracting Officer.

PART 3 - EXECUTION (SURVEY REQUIREMENTS)

3.1 SURVEY NOTES

A. The Contracting Officer shall approve format for submitted slope stake notes. A sample format will be supplied upon request from the Contractor.

B. Manually recorded survey notes shall be printed in characters at least 0.15 inches height and shall be legible at a distance of 2.5 feet. Errors shall be deleted by lining out. Date, crew names, and positions, instrumentation, and weather shall be recorded in the notes at the beginning of each day’s work. The party chief shall sign or initial each page of the notes immediately after the last entry for each day’s work.

C. Electronically recorded survey notes shall be consecutively numbered and headed to identify the contents. The electronic survey information shall be supplied on a 3.5” floppy disk or on in CD format. Electronic information shall be AutoCAD R14 compatible. Points shall be identified to correspond to the drawings or identified appropriately on the electronic file. The notes shall be supported and accompanied by a bound Day Book that records the project name and for each day identifies date, crew names and positions, instrumentation, weather, type of survey, stationing of sections between which survey was performed, and survey data or sketches that cannot be electronically recorded. The party chief shall sign or initial the electronically recorded note and Day Book immediately after the last entry for each day’s work.

3.2 MARKING STAKES

A. All stakes shall be legibly marked in a format approved by the Contracting Officer. A sample format will be provided upon request from the Contractor. Marking shall conform to the nomenclature below or as agreed to by the Contracting Officer:

PI

Point of Intersection of tangents

PC

Point of Curvature

POC

Point on Curve

PT

Point of Tangency

POT

Point on Tangent

RP

Reference Point

L L-Line (Final location line)

BVC

Begin Vertical Curve

CVC

Center of Vertical Curve

EVC

End Vertical Curve

BM

Bench Mark

TBM

Temporary Bench Mark

BT

Begin Taper (any)

ET

End Taper (any)

DD

Drain Dip

C Cut

F Fill

CL

Centerline

D Ditch

W Width

3.3 PRECISION AND ACCURACY REQUIREMENTS

A. Establishing Coordinate Layout Points, including points for Centerline for Roadway and Taxiway, AS SHOWN ON THE DRAWINGS.

1. Minimum Position Closure:

1/5000

2. Angular Accuracy

2 sets, direct/reverse, 20” rejection limit

3. Vertical Closure

0.01 ft/100 ft

4. Horizontal and vertical accuracy for slope stake, slope stake references, and clearing limits in feet or percentage of horizontal distance measured from control point, coordinate point or reference stake; whichever is greater:

a. Slope reference stakes and slope stakes = 0.15 ft or 0.6%.

b. Clearing limits = 1.0 ft.

C. Maximum allowable deviation from construction stakes and drawings:

1. Base Course Width = +0.2 feet

2. Sub Grade Elevation = +0.05 feet

3. Centerline and Offset Alignments = +0.1 feet

4. Slopes and Earthwork (Percent Slope) = +3%

5. Curbs, Gutters, Sidewalks, Drainage and Other Structures

a. Elevation = +0.1 feet

b. Horizontal = +0.1 feet

6. Utilities

a. Elevation = +0.1 feet

b. Horizontal = +0.1 feet

3.4 SURVEY CONTROL POINTS AND BENCHMARKS

A. In the process of preparing the topographic map of the project site, prior to design, a network of survey control points/benchmarks has been established on the ground. The coordinates and elevations of these physical markers, and their locations, are AS SHOWN ON THE DRAWINGS, and form the basis for construction staking. All horizontal and vertical control shall be generated from these control points. Depending upon the layout of the proposed project, control points may be required in additional and/or alternative locations. It is the responsibility of the Contractor to maintain existing control points and set supplemental points as required for proper staking.

B. Physical standards for new and replacement markers:

1. Markers set in ground shall be rebar or pipe at least 1/2 inch in diameter and 18 inches in length, with a metallic cap at least 1.5 inches in diameter.

2. Markers set in existing pavement or other hard surfaces may be 40 penny or greater nails or "PK" nails with a metallic disc or washer at least 1.5 inches outside diameter.

3. At a minimum, the cap or washer will be stamped with the unique identifying point number. This number is typically the next unused number in the series indicated by the existing control points provided by the Forest Service. Other markings may include "CP", and "USFS" or the name of the firm setting the point. If the Contractor's surveyor has similar markers with pre-stamped markings, these may be used. However, some markings must be added or deleted to indicate that the marker is not a property or land boundary monument.

C. Method of survey for new survey control points:

1. New control points will be set by traversing through the new points and two (2) existing control points and measuring the closing angle at the second existing point. If ratio of closure meets the precision and accuracy standards defined in paragraph 3.3 above, the coordinates of the new points will be adjusted by any standard traverse adjustment method.

2. Where single control points are added between two (2) existing points, the new point may set as in C.1, or by locating the new point from two (2) existing points. If the error circle for the two different coordinate positions meets the precision and accuracy standards defined in paragraph 3.3 above, the coordinates of the new point will be the mean of the two observed positions.

3. Conventional differential levels or three-dimensional traverse (“trig. levels”) may be used to determine elevations as long as closures meet the precision and accuracy standards defined in paragraph 3.3 above.

3.5 DISCREPANCIES

A. The Contractor shall compare the staked coordinate points with the design coordinate points. Differences between previously recorded and observed elevations of benchmarks shall be referred to the Contracting Officer. Differences exceeding 1/2 degree in angle from the alignment data AS SHOWN ON THE DRAWINGS and the alignment observed on the ground shall be referred to the Contracting Officer. Differences in elevations exceeding 1/2 foot at any two or more consecutive points shall be reported to the Contracting Officer for evaluation and possible revision. Staking of these areas shall be deferred until the Contracting Officer resolves these differences.

B. Simple adjustments such as blending fillet curves to remove overlaps shall be completed by the Contractor by adjusting the radius of the smaller curve. All other necessary adjustments shall be referred to the Contracting Officer.

3.6 CLEARING LIMIT, SLOPE, AND REFERENCE STAKES

A. Clearing limits shall be staked when requested by the Contracting Officer.

1. The clearing limits shall be located on the ground to the dimensions AS SHOWN ON THE DRAWINGS or specified by the Contracting Officer.

2. The location shall be within the tolerances specified in paragraph 3.3.

3. The clearing limits shall be marked with lath, flagged, or other methods approved by the Contracting Officer.

4. Method for recording clearing limit data on stakes shall be approved by the Contracting Officer.

B. Slope catch points and slope reference stakes shall be established. The position of these stakes shall be determined by methods that will produce on the ground the designed template AS SHOWN ON THE DRAWINGS to the precisions shown above and specified for this contract.

1. Method for recording slope stake information on stakes shall be approved by the Contracting Officer.

C. The Contractor shall establish slope reference stakes at a minimum horizontal distance of 10 feet beyond the slope catch point (or clearing limits).

1. The elevation and location of slope reference stakes shall be verified for accuracy by differential leveling between slope reference stakes of adjacent points.

a. Where the difference in reference stake elevation between that established by slope staking and that observed by differential leveling exceeds the allowed tolerance, the slope stake shall be reset.

2. Record on the reference stakes the horizontal distance to the nearest coordinate point and the vertical distance to the construction grade.

3. The offset from the slope stake catch point and slope stake catch point information shall be recorded on the reference stake and in the slope stake book.

4. Method for recording slope stake information on reference stakes shall be approved by the Contracting Officer.

3.7 MONUMENTS OF PROPERTY BOUNDARIES OR SURVEYS OF OTHER AGENCIES

A. If property boundary or survey monuments, or survey markers of other agencies, are found within or adjacent to the construction limits, the Contractor shall immediately notify the Contracting Officer.

1.

Existing Monuments shall be protected at all times and tied to the control survey as references.

3.8 STAKING DRAINAGE AND OTHER STRUCTURES

A. Stakes shall be set at all drop inlet and manhole locations. A reference stake and hub shall be set on the centerline 10 feet from each end or beyond the clearing limit, whichever is greater. The following shall be recorded on these stakes:

1. Diameter, size and type of structure.

2. The vertical and horizontal distance from hubs to the centerline invert.

B. The Contracting Officer prior to commencement of construction shall review other structures located in conjunction with site staking. Adjustments necessary for any relocation of said structures shall be furnished to the Contractor. This shall be considered a changed condition.

3.9 GRADE FINISHING STAKES

A. Finishing stakes shall be set. Sub grade finishing stakes shall be blue tops. Base course finishing stakes shall be red tops.

B. Stakes shall be nominal 1-inch by 1-inch hubs and shall be of sufficient length to provide a solid set.

C. Finishing stakes shall be placed at all centerline stations established. Stakes shall be set at Centerline and at the edge of finished surface.

D. Finishing stakes shall be set when sub grade is within 0.5 feet, or base course is within 0.2 feet of final grade. The stakes shall be set to the nearest 0.02 feet of the measured grade line.

3.10 STAKE APPROVAL AND MAINTENANCE

A. Construction work shall not begin within an area of the site until the Contracting Officer has approved the stakes, marks, and controls established by the Contractor in writing. The minimum segment for approval shall be 20,000 sq. ft. of the project.

B. Approval of the construction staking will not relieve the Contractor of the responsibility for maintaining the survey work and for correcting errors, whether the errors are discovered during the actual survey work or in subsequent phases of the project. Stakes will be maintained or referenced with the appropriate staking format.

END OF SECTION

DINKEY MILL & BLUE CANYON HELIPADS

SIERRA NATIONAL FOREST

DIVISION 2 02001-7