Chapter 2 of 429% of exam

Earthwork and Grade Control

CSLB weights Earthwork and Grade Control at about 29% of the C-12 exam: grade control, soils and geology, excavation and trenching, and fill and grading. This page is a short survey; the PrepPass C-12 Earthwork and Paving study guide teaches the section with the Cal/OSHA excavation rules, worked examples and a full practice exam.

Grade control

A stake is a cut or fill from existing ground, and a tolerance has a direction.

Base grade
The finished aggregate base surface is within 0.05 foot of the established grade.
Caltrans 2024 Standard Specifications §26-1.03E
Curb and gutter
Flat to within 0.01 foot under a 10-foot straightedge.
Caltrans 2024 Standard Specifications §73-2.03A

Soils

A competent person classifies every deposit with at least one visual and one manual test.

Soil types
Type A is cohesive soil of 1.5 tons per square foot or more with no disqualifiers; sand and submerged soil are Type C.
8 CCR §1541.1 Appendix A
Relative compaction
Field dry density divided by laboratory maximum dry density, times 100.
Caltrans 2024 Standard Specifications §19-5

Excavation and trenching

Five feet or more, or any sign of a cave-in, needs a protective system; the maximum slopes depend on soil type.

Maximum slopes
Under 20 feet deep: Type A 3/4:1, Type B 1:1, Type C 1-1/2:1; more than 20 feet needs an engineer.
8 CCR §1541.1 Appendix B
Edges and egress
Ladders within 25 feet of lateral travel at 4 feet deep or more; spoil at least 2 feet from the edge.
8 CCR §1541(c)(2), (j)(2)

Fill and grading

Fill goes in thin lifts at the specified moisture to a specified density, and it is tested.

Embankment
Lifts of 8 inches loose at most; 95 percent in the defined zones and 90 percent elsewhere.
Caltrans 2024 Standard Specifications §19-5, §19-6
Aggregate base
Each layer to 95 percent; no compacted layer thicker than 0.50 foot.
Caltrans 2024 Standard Specifications §26-1.03

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