GEOTECH & PAVEMENT DESIGN SCOPE OF WORK GUIDELINES FOR DESIGN CONSULTANTS

(Standard Language for Preliminary Engineering and Final Design for County Road Projects – Modify as needed)

?.	GEOTECHNICAL & PAVEMENT DESIGN REPORT

Sampling and testing procedures will be in accordance with California Department of Transportation (Caltrans) testing requirements unless otherwise noted. These guidelines serve as an “addition to” the requirements and not to be construed to replace sections of the Geotechnical Design Reports (GDR). The final Geotechnical and Pavement Design Report will be prepared in accordance with the guidelines presented in the Caltrans Guidelines for Preparing Geotechnical Design Reports, Version 1.3, dated December 2006.

I.	Field Investigation

1.	On existing roadway, cores shall be drilled at 500-ft spacing or smaller when there is a change in the structural section and/or variability in surface distresses. The depth of the core/bore shall be at a minimum of 10-ft. On 3-to 4-lane or larger roadway, the core/bore locations shall be staggered.

2.	On new (proposed) roadway alignment, bores shall be at a minimum of 20 ft deep or until refusal when rock or highly cemented material is encountered. Bores shall be drilled at 250-ft spacing or smaller when there is a change in subgrade soil. The type of soils shall also be determined for slopes (cut) and valleys (fill) along the roadway alignment. New cuts and embankment fills with heights greater than 10 ft shall be assessed and evaluated for drainage such as terrace drain, etc.

3.	When the existing pavement structural section warrants an overlay design, a deflection analysis shall be conducted for that segment of the roadway. The spacing for deflection test shall be at 250-ft interval for each travel lane.

4.	For cut slope especially in rocky areas, seismic refraction testing shall be performed to determine rock strength and rippability.

5.	Groundwater shall be noted when encountered. Its location and depth relative to ground surface shall be noted and identified on the boring logs.

6.	Existing drainage facilities and structures such as culvert crossings, Portland Cement Concrete (PCC) dip section, retaining walls, etc., shall be inspected and assessed for its condition, dimensions, and operation.

7.	Location of proposed bore holes shall be cleared with USA Dig Alert for utility conflicts.

II.	Sampling

1.	Subgrade soils and/or base materials shall be sampled for soil engineering properties determination at a minimum of one (1) per 1000 ft of roadway length. Additional samples shall be required based on the type of soil encountered during the coring and boring operation as described in par. I.(1) and I.(2) above.

2.	Moisture samples for the in-situ materials shall be taken for every R-Value sample.

3.	Soil samples shall be collected for corrosion testing at a minimum of one (1) sample on similar soils for existing structures and one (1) sample for every proposed drainage structures.

III.	Laboratory Testing

Soil samples collected shall be tested, but not limited to, for the following soil properties:

1.	R-Value (CTM 301)

2.	Sand Equivalent (CTM 217)

3.	Plasticity Index (CTM 204)

4.	Max Density (CTM 216)

5.	Gradation (CTM 202)

6.	pH (CTM 643)

7.	Minimum Resistivity (CTM 643)

8.	Sulfate content (ppm) (CTM 417)

9.	Chloride content (ppm) (CTM 422)

IV.	Permit

1.	An encroachment permit application shall be submitted to the County of Riverside, Permit Section, for any field activities within the paved roadway including traffic control handling. The permit will be issued to the geotechnical consultant for a “no fee permits.”

2.	Right of entry to private properties, if required, shall be conducted by the County of Riverside. The geotechnical consultant shall notify the County 8 weeks in advance prior to proposed field work within said properties. Plans and field related information shall be required from the consultant to expeditiously process the right of entry in a timely manner.

V.	Review

Prior to any field activities, the proposed field investigation plan shall be submitted to the County including exploratory plans showing sample locations, photos, and other pertinent information. The field investigation plan will be reviewed by the County Transportation Materials Engineer or his designee.