The Foundation of Stable Structures
Geotechnical soil testing and proper soil compaction are critical to prevent foundation settlement, cracking, and structural failure.
1. The Proctor Compaction Test
Using the laboratory Modified Proctor Test (ASTM D1557), we establish the soil's optimum moisture content and Maximum Dry Density (MDD). In-situ compaction tests (sand replacement or nuclear gauge) verify that the subgrade reaches 95% to 98% MDD before laying concrete.
2. Shoring Regulations & Safety
Under safety codes (the OSHA 4-foot rule), any excavation reaching a depth of 1.2 meters (4 feet) must utilize shoring, shielding, or sloped banks to prevent soil collapse. Deep basements require engineered sheet piles or soldier piles.
3. Concrete Grade Selection
We use Class 25 concrete (25 MPa) for standard residential suspended slabs and columns, and Class 30/Class 35 concrete (30-35 MPa) for heavy retaining walls and commercial foundations.