2106.01 DESCRIPTION.
This work consists of furnishing and installing settlement plates consisting of a base plate, steel bar, steel riser pipe sections, PVC casing, inspection cover, and any additional hardware and couplers which may be required as shown in the contract documents.

This work also consists of monitoring settlement plate installations and reporting settlement results.

The number of settlement plates will be shown in the contract documents.

2106.02 MATERIALS.
Materials shall meet the requirements of Division 41.

A. Base Plate and Steel Bar.
Section 4153 shall apply.

B. PVC Casing.
Article 4146.04 shall apply.

2106.03 CONSTRUCTION.
Settlement plates shall be furnished and installed by the Contractor at locations specified in the contract documents. Benchmarks shall be established in the adjacent area before settlement plates are installed. The method of determining alignments and elevations and the method of preserving control points shall be subject to the 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. Settlement plates shall be approved by the Engineer before beginning embankment construction.

A. Initial Installation.
The base plate shall be installed at least 6 inches (150 mm) below natural ground, firmly seated on a level surface. The PVC casing shall be placed on the base plate, centered on the steel bar attached to the base plate. The void between the casing and bar shall be filled with commercial grade oakum, tightly packed, in order to keep the casing centered on the bar.

An inspection cover shall be constructed as shown in the contract documents and placed over the top of the casing. The cover shall remain in place at all times, except when inspection or monitoring of the riser pipe is being performed.

B. Adding Extensions.
Riser pipe extensions and couplers shall be added, as necessary, in 3 foot (1 m) increments as construction of the embankment progresses. The Contractor shall install extensions in a plumb line.

Sections of PVC casing and couplers shall also be added, as necessary, in order to prevent fill material from coming into contact with the steel pipe extensions.

C. Final Cleanup.
After all embankment construction and monitoring has been completed, the tops of the riser pipe and PVC casing shall be adjusted so they terminate below the final elevation of the embankment.

The Contractor shall remove riser pipe sections protruding above the surface of the embankment. The PVC casing shall then be cut at a point below the surface of the embankment and covered with a PVC cap, solvent welded to the casing, in order to prevent the intrusion of soil and water.

D. Monitoring.
Monitoring shall consist of inspecting the riser pipe, accurately measuring the elevation of top of the riser pipe, and recording to the nearest 0.01 foot (0.3 mm) the elevation readings on a form supplied by the Engineer.

The Contractor shall record elevation readings daily during normal construction and weekly during delays and following the completion of embankment construction. During the course of embankment construction, completed forms shall be submitted to the Engineer weekly. Following the completion of embankment construction, forms shall be submitted weekly unless otherwise directed by the Engineer.

During periods of work suspension, the Engineer will record elevation readings.

E. Limitations.
All necessary precautions shall be taken to keep the alignment of the riser pipe and PVC casing in a plumb position. The Contractor shall operate equipment so that the riser pipe and PVC casing are not damaged, displaced, or tilted out of plumb. All pipes that are damaged, displaced, or tilted out of plumb shall be repaired or replaced, at the discretion of the Engineer and at no additional cost to the Contracting Authority.

2106.04 METHOD OF MEASUREMENT.
Settlement plates will not be measured directly for payment.

2106.05 BASIS OF PAYMENT.
The cost of furnishing, installing, extending, and monitoring settlement plates shall be considered incidental to embankment or excavation.