Improvement in San Bernardino demands a rigorous understanding of the region's challenging subsurface conditions, shaped by the San Andreas and San Jacinto fault systems. Alluvial fan deposits, liquefiable sands, and collapsible soils dominate the basin, requiring targeted strategies to enhance bearing capacity and mitigate seismic hazards. Our approach begins with a comprehensive geotechnical investigation, integrating desktop studies with field exploration to map soil variability. We adhere strictly to California Building Code Chapter 18 and ASCE 7-22, while local ordinances often reference Caltrans Standard Specifications for ground modification techniques such as dynamic compaction, stone columns, and deep soil mixing.
Our methodology relies on a suite of in-situ tests to characterize target strata before designing any improvement program. We deploy CPT (Cone Penetration Testing) per ASTM D5778 to obtain continuous profiles of tip resistance and sleeve friction, which are critical for identifying liquefiable layers and evaluating the effectiveness of densification. Complementary SPT (Standard Penetration Testing) following ASTM D1586 provides disturbed samples and N-values for empirical correlations with relative density. For modulus-based settlement analyses, we perform the Flat Dilatometer Test (DMT) under ASTM D6635 and the Ménard pressuremeter test (PMT) per ASTM D4719, delivering direct measurements of soil stiffness and limit pressure essential for verifying improvement in overconsolidated clays and cemented alluvium.
Typical projects in San Bernardino range from warehouse logistics centers in the Inland Empire to critical infrastructure along the I-10 and I-215 corridors, where liquefaction-induced settlement poses a direct threat to bridge approaches and heavily loaded slabs. We frequently design Improvement for big-box retail pads and water treatment plants, where post-construction total and differential settlements must not exceed 1 inch in 30 years. In these scenarios, rigorous quality control is non-negotiable; we verify densification through post-treatment CPT soundings and field density tests (sand cone method) in accordance with ASTM D1556, ensuring that minimum blow counts and relative density targets—often exceeding 70% for earthquake-prone zones—are uniformly achieved.
Our process integrates pre- and post-improvement In-Situ to deliver a closed-loop verification package. We obtain undisturbed samples (Shelby tube) in fine-grained interbeds for laboratory consolidation and strength testing, confirming that treatment has mitigated collapse potential. Deliverables include a stamped Geotechnical Completion Report with as-built records, acceptance criteria per project specifications, and a direct comparison of pre- and post-Improvement parameters. By linking subsurface characterization from investigation through execution, we provide owners and contractors in San Bernardino with a defensible, code-compliant foundation solution that reduces risk and accelerates construction schedules.