In 2018 the San Francisco Unified School District chose to perform a voluntary seismic addition at Claire Lilienthal Elementary School and engaged ENGEO to perform a geologic hazard assessment, prepare construction drawings and specification for strengthening the soil below existing and new footings, and provide quality control and quality assurance during construction. The ground improvement work resulted in an increased level of safety for the students, teachers, and faculty while maintaining the historic and cultural significance of the building. Upon finishing the project ENGEO was awarded the CalGeo 2020-2021 Outstanding Project Award.
ENGEO selected ground improvements comprising of compaction and permeation grouting to limit differential settlement due to liquefaction under footings to 0.5 inches over a span of 30 feet. Furthermore, ENGEO provided continuous inspection and construction consultation, helping to ensure the improvement followed the project plans and specifications for the various field conditions encountered.
The project schedule was rapidly accelerated as a result of the state mandated COVID-19 lockdown, transitioning ENGEO’s work from the field verification test section directly into production work. The ground improvement achieved the project performance criteria, reduced construction costs by 50 percent, and accelerated project completion to less than 5 months.