Riverside lies within a seismically active basin where deep alluvial deposits and proximity to the San Andreas and San Jacinto fault zones amplify shaking and elevate liquefaction risk. Our seismic evaluations address these conditions under CBC Chapter 16 and ASCE 7-22, starting with seismic amplification analysis to quantify site-specific ground motion increases. Where shallow groundwater and loose sands prevail, we pair that with soil liquefaction analysis to assess triggering and settlement potential per CDMG Special Publication 117 guidelines.
These studies are essential for mid‑rise and high‑occupancy structures, bridge foundations, and critical infrastructure where code‑prescribed spectra may be unconservative. For performance‑based design, we integrate site response analysis to capture nonlinear soil behavior and basin effects. The resulting parameters feed directly into foundation proportioning and, where warranted, base isolation seismic design to reduce demand on superstructures.
Pre-stressed tendon systems for permanent retaining walls and slope stabilization. Includes lock-off load verification and long-term creep monitoring.
Temporary or permanent tiebacks for shoring and excavation support. Designed per PTI and IBC with proof testing on every anchor.
Soil chemical testing to classify groundwater aggressivity. Recommends Class I or II protection based on chloride and sulfate levels.
Field load testing to 133% of design load with digital data logging. Reports include load-displacement curves and pass/fail criteria.
PTI DC35.1-14 (Post-Tensioning Institute), ASCE 7-22 (Minimum Design Loads), ASTM A416 (Steel strand specification), IBC 2021 (Chapter 18, Soils and Foundations)
An active anchor is pre-stressed after installation, applying a tensile load to the tendon before the structure sees service loads. A passive anchor (tieback) is not pre-loaded — it resists load only as the structure moves. Active anchors are used for permanent walls and slopes where movement must be minimized. Passive anchors work well for temporary shoring where some deflection is acceptable.
Anchor design fees for a typical project range between US$910 and US$3.870, depending on the number of anchors, soil testing required, and complexity of the load conditions. This includes bond zone calculations, corrosion protection selection, and proof test specifications. Site investigation costs are separate.
Alluvial sands and gravels near the river give good bond stress (15-30 psi), but loose fills and colluvium on the hillsides can drop that to under 10 psi. Groundwater fluctuation also reduces bond zone effectiveness, especially in silty sands. We always run grain size and direct shear tests on samples from the bond zone depth.
Yes. Groundwater in parts of Riverside has elevated sulfate and chloride levels, especially near the Santa Ana River and in areas with historic agricultural use. PTI DC35.1 requires Class I double corrosion protection for permanent anchors in aggressive soil. We test groundwater chemistry during the site investigation to confirm the correct class.
Design typically takes 2 to 4 weeks, including soil analysis and bond zone calculations. Proof testing on site adds another 1 to 3 days per anchor, depending on access and crew size. We coordinate with the contractor to avoid delays — testing usually happens right after tendon installation and before wall construction.