2526.01 DESCRIPTION.
This work involves survey for construction projects. The Contractor shall furnish all survey necessary for construction of the project before work begins in the area. The provisions of Article 1105.06 do not apply to this work, except that the original stakes set by the Engineer shall be preserved. If, in the opinion of the Engineer, any of the original survey stakes or benchmarks have been destroyed or disturbed by the Contractor, the cost of replacing shall be charged to the Contractor. Design errors discovered shall be brought to the Engineer's attention for review prior to staking. Construction survey shall include qualified personnel, equipment, and supplies required for, but not limited to, the following items:

A. Project Control.

1. Primary Control Monuments.
A primary control monument is a survey point established by the Department prior to project commencement and shown in the contract documents. The point will be established by placing a monument in the ground.

2. Secondary Control Monuments.
A secondary control monument is a survey point established by the Contractor on grading or other projects specified in the plans, and preserved by the Contractor on all other projects.

The Engineer will provide monuments, similar to those used for Global Positioning System (GPS) control by the Department.

Secondary permanent horizontal control monuments shall be placed, as directed by the Engineer, at locations likely to survive project construction and at intervals not to exceed 2,640 feet (0.8 km). The Contractor shall place the monuments in the ground along the project corridor. Monuments shall be placed at higher elevations along the corridor to provide a view of the immediate project topography and provide for visible clear line of sight to the nearest secondary permanent control monument in either direction. Primary project monuments may be substituted if appropriate.

The monument shall by planted 1 to 4 inches (25 mm to 100 mm) below existing ground. A metal fence post shall be driven within 1 foot (0.3 m) to mark its location.

Project coordinates shall be carefully determined relative to the nearest primary project control monument using project coordinate values provided by the Engineer. The resulting error radius of the secondary monument shall not exceed 0.10 feet (30 mm) ±2 ppm relative to the primary control. Unedited printed and/or electronic formatted field data of the field survey shall be provided to the Engineer along with an ASCII comma delineated file of the coordinates formatted as (Point Number, Northing, Easting, Elevation, Point Description, Feature).

An independent traverse check between the secondary control monuments shall be performed by observing distance and angular measurements or by use of GPS. An unedited printed and/or electronic file of the field data for the traverse check shall be provided to the Engineer. A diagram shall be provided to the Engineer indicating horizontal ground distances to nearest 0.01 foot (3 mm) and angles to at least the nearest 10 seconds between each secondary control monument. Inverses between the coordinate pairs as determined in the previous paragraph shall not exceed 0.10 feet (30 mm) of the direct measurements.

Secondary control monuments that are disturbed during construction activities will be replaced using procedures outlined above at the no additional expense to the Contracting Authority.

3. Durable Physical Objects
Each control monument shall be referenced to at least three durable physical objects from 20 to 100 feet (6 m to 30 m) away from the monument with measurements to the nearest 0.10 foot (30 mm). Durable physical objects could include trees, poles, fence posts, station marks in new roadway pavement, or metal fence posts. A printed and/or electronic reference image (for example .JPG, TIFF, etc), including each reference and project coordinate, shall be provided to the Engineer.

4. Benchmarks.
Permanent vertical control benchmarks shall be established at all bridges and reinforced concrete box culverts within the project. An I.D.O.T. brass plug on bridge barrier rail or headwall of reinforced concrete box culvert shall be used to indicate the benchmark. The Contractor may use a sawn “X” on bridge barrier rail or headwall of reinforced concrete box culvert if approved by the Engineer.

All benchmark elevations shall be transferred from construction plan benchmarks to the permanent benchmarks using the three-wire method or by trigonometric leveling. Temporary benchmarks of reasonable stability shall be used to preserve the plan benchmarks.

All unedited printed and/or electronic formatted field benchmark elevation data shall be provided to the Engineer. The project x and y coordinates of all benchmarks shall be provided to the Engineer along with an ASCII comma delineated file of the coordinates formatted as (Point Number, Northing, Easting, Elevation, Point Description, Feature).

Benchmark level loops shall not exceed an error of 0.05 feet (15 mm) times the square root of the loop’s length in miles (kilometers) and the error shall be distributed equally along the loop on all intermediate traverse/benchmark points.

B. Grading.
Right-of-way line between permanent right-of-way corners at 100 foot (20 m) intervals, or less if needed, including borrows, temporary easements, and right of entry. These points shall be marked by placement of a metal pin or wood hub, flat, and lath at the same location as the slope stakes. The flat shall be clearly marked with the station number, distance from centerline, and elevation (cut or fill) to subgrade.

Slope stakes at 100 foot (20 m) intervals, or less if needed, for all embankment and excavation work including roadway, channel changes, and borrow areas. Interpolations may be necessary to match the cross-sections. Slope stakes shall be set at the toe of the foreslope, and/or the top of the backslope. Slope stakes shall be marked with a flat and lath. The flat shall be clearly marked with the station location, distance, slope, and cut/fill information.

Grade check stakes at 100 feet (20 m) intervals for bottoms of subgrade treatments. Grade check stakes shall be set on centerline for two-lane roads and in the median for four-lane roads. Grade check stakes shall be marked with a lath. The lath shall be clearly marked with the station location and cut or fill information.

Finish grade stakes (blue tops) at 100 foot (20 m) intervals, or less if needed. The blue tops shall be set at each shoulder line and at each point where there is a change in cross slope. Blue tops shall be marked with a wood hub and a stake chaser or similar type tassel.

Take original and final elevations of all borrows. Provide original and final graphical cross sections at 100 foot (20 m) intervals, or less if needed, suitable for use by the Engineer to calculate excavation quantities.

Bridge berm slope stakes to establish all transitions including the face of the berm. Finish grade stakes (blue tops) on all roadway shoulder lines and roadway centerlines project down the face of the bridge berm at the top, midpoint, and toe.

When Class 12 excavation is an item, cross section elevations shall be taken at 100 foot (20 m) intervals, or less if needed, and cross sections plotted for use by the Engineer to calculate the excavation quantities.

Agricultural drain tile shown in the contract documents shall be located on each side of roadway at the right-of-way line with a lath. The lath shall be clearly marked to show station location, distance from centerline, tile size and type, and flowline elevation.

C. Bridges.
Locations and elevations shall be marked with metal pin or tack in a wood hub, flat, and lath. The flat shall be clearly marked with the pier/abutment station location, design number, and offset distance from the centerline of the approach roadway.

Minimum of three temporary benchmarks.

Location of test pile shall be marked with a wood hub.

Independent check of the above stakes.

Elevations of all completed substructure beam seats shall be submitted to the Engineer for review prior to installation of bearings and superstructure elements.

Elevations of beams as erected. Provide the elevations to the Engineer for computation of finish elevations for deck construction. Locations for determining beam elevations shall be in accordance with the plans.

A copy of the staking diagram shall be provided to the Engineer before work begins.

D. Reinforced Concrete Box Culverts.
Locations and elevations shall be marked with metal pin or tack in a wood hub, flat, and lath. The flat shall be clearly marked with the station location, design number, cut/fill elevation, and offset distance from the centerline of the culvert and back of parapet.

An independent check of the above stakes.

A copy of the staking diagram shall be provided to the Engineer before work begins.

Questionable flow lines and alignments that do not match existing drainage shall be reported to the Engineer.

E. Pipe Culverts.
Locations and elevations shall be marked with metal pin or a wood hub, flat, and lath. The flat shall be clearly marked with the station location, cut/fill elevation, and offset distance to both ends or centerline of pipe.

Questionable flow lines and alignments that do not match existing drainage shall be reported to the Engineer.

F. Sanitary and Storm Sewers.
Locations and elevations shall be marked with metal pin or tack in a wood hub, flat, and lath. The flat shall be clearly marked with the station location, pipe number, cut/fill elevation, and offset distance to centerline of pipe.

G. Water Mains.
Locations and elevations shall be marked with metal pin or tack in a wood hub, flat, and lath. The flat shall be clearly marked with the station location, pipe number, cut/fill elevation, and offset distance to centerline of pipe.

H. Intakes and Utility Accesses.
Locations and elevations shall be marked with metal pin or tack in a wood hub, flat, and lath. The flat shall be clearly marked with the station location; intake or utility access number; cut/fill elevation, including bottom of well and form grade; and offset distance to the Station Location.

I. Pavements (PCC & HMA).
Locations and elevations shall be marked with metal pin or tack in a wood hub (only tack one side), flat, and lath. Elevations on both sides of the pavement at 50 foot (10 m) intervals on straight and level sections and at 25 foot (10 m) intervals on horizontal and vertical curves. The flat shall be clearly marked with the station location, cut/fill information, and offset distance to the edge of pavement. Pavement cross slope information shall be included in superelevated curves.

Elevations of pavement centerline, and both edges at bridges and existing pavement, shall be taken at 10 foot (3 m) intervals for 100 feet (30 m). Final elevations shall be submitted to the Engineer for approval.

When a new profile grade is not included in the contract documents the Contractor shall:

1. Obtain elevations of the existing shoulders and/or pavement as stated in Article 2526.01, I .

2. Design a smooth profile grade line based on these elevations to provide the required pavement or shoulder thickness as detailed in the contract documents. This grade line shall tie into existing bridges, adjacent pavement and ramps, and provide the required pavement crown. This proposed grade line shall be submitted to the Engineer for approval.

J. Pavement Overlays (PCC and HMA)

Reference and preserve existing control points located at each Point of Intersection (P.I.).

Method used to reference points shall be approved by the Engineer.

Control Points shall be reset after the work is complete.

K. Structural Walls.
Survey requirements for structural walls shall include the following work types:

Mechanically Stabilized Earth (MSE) Walls
Cast in Place (CIP) Retaining Walls
Soil Nail Walls
Tie Back Walls
Noise Walls
Modular Block Retaining Walls
Segmental Retaining Walls

Locations and elevations shall be marked with a metal pin or a wood hub, flat, and lath. The flat shall be clearly marked with the station location, cut/fill elevation, and offset distance to face of wall.

The method used by the Contractor to preserve project control shall be submitted to the Engineer for approval. Survey work documentation shall be in a format acceptable to the Contracting Authority. Survey work shall be done with a Professional Engineer licensed in the State of Iowa or a Professional Land Surveyor licensed in the State of Iowa in responsible charge, in accordance with provisions of Chapter 542 B, Code of Iowa. The Contractor shall submit to the Engineer a resume identifying the field survey personnel and their capabilities to perform the intended requirements.

The method of determining alignments and elevations and the method of preserving control points shall be subject to review and approval by the Engineer. This approval shall not act to relieve the Contractor of the responsibility for the correctness of the survey work. Plan cross-sections shall not be used for vertical or horizontal control.

The Engineer will provide bench mark elevations, right-of-way corners, and reference control points on the original survey as shown in the contract documents. A GeoPak alignment will be provided if available.

Tie-ins with existing roadways shall be checked for correctness of alignment prior to construction staking.

When survey work is done under traffic, detail sheets in the contract documents will establish the required signing.

The Engineer will locate and determine elevations of settlement plates.

The Contractor shall replace land corners and permanent reference markers unless otherwise stated in the contract documents.

All survey work documentation is to become property of the Contracting Authority. The work of this specification will be considered finished when the documentation is furnished to and accepted by the Engineer.

For the purpose of subcontracting, this item will be considered a specialty item.

2526.02 METHOD OF MEASUREMENT AND BASIS OF PAYMENT.
Construction survey will be measured and paid for at the lump sum contract price. This payment shall be full compensation for the survey work required for the project as let, including any interpolations that may be necessary between cross-section and field staking. Revisions after the letting will be paid for as extra work as described in Article 1109.03, B.