Building Class A Development Over Landfill-Video

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Video Summary

Langan engineers described the geotechnical challenges of building luxury, Class A developments over a closed landfill in North Miami. The 193-acre site contains 20–25 feet of highly variable waste, creating risks from settlement, unstable foundations, damaged utilities, contamination, and methane. Because landfill material had to remain on-site, three test sections evaluated deep dynamic compaction (DDC) and preload performance.<br /><br />Tests showed that 80–90% of primary settlement occurred within about a month. DDC reduced settlement, and two passes proved sufficient; combining DDC with preload and then removing the preload minimized long-term creep. Recommendations varied by site use, with both methods used near settlement-sensitive structures.<br /><br />Buildings were supported on auger-cast piles extending into underlying limestone and cemented sand. Large-diameter piles required predrilling to identify and remove obstructions, especially tires. Long-term monitoring indicates infrastructure settlement is below 0.1 inch annually. The project demonstrates the value of site-specific testing, tailored ground improvement, and ongoing monitoring when developing landfills.

Keywords

North Miami landfill development

geotechnical engineering

deep dynamic compaction

preload settlement testing

auger-cast piles

ground improvement monitoring