Instrumented Load Testing and Construction Monitoring of Rigid Inclusions in Seattle-Video

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The presentation described a Seattle design-build project using rigid inclusions to support a process building over deep alluvial soils. The system was designed primarily to control static settlement, with 18-inch-diameter inclusions spaced six feet apart beneath a load-distribution mat. Analyses predicted 2.4 inches of total settlement, reduced to 0.4 inches after water preloading, and about 10 inches of liquefaction-induced settlement.<br /><br />Three static load tests confirmed design assumptions. Nearly 600 inclusions were installed in 18 working days. Quality control included installation-record reviews, grout-strength testing, and integrity testing. Integrity tests identified suspected breaks, likely caused by soil densification as equipment installed adjacent rows. Because the structure could tolerate settlement and did not require lateral resistance, construction continued.<br /><br />Instrumentation showed tensile strains associated with the breaks. Settlement monitoring found actual settlement was about two-thirds of predictions. The presenters concluded that rigid inclusions were economical and fast to construct for this application, but projects requiring lateral resistance should include reinforcement or other measures to prevent breakage.

Keywords

rigid inclusions

Seattle project

static settlement

alluvial soils

liquefaction settlement

quality control testing