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

PPT Presentation

Pdf Summary

The presentation describes the design, testing, installation, and monitoring of rigid inclusions (RIs) for a project in Seattle. The site’s settlement-sensitive components—including weir plates, crane rails, UV channels, mixers, and large-diameter pipe connections—required control of total and differential settlement. The design also considered liquefaction-induced settlement and used a 3D Plaxis model to select RI dimensions and spacing.<br /><br />The system consisted of 18-inch-diameter RIs spaced 6 feet on center and extending approximately 35 feet below the load distribution mat. Analysis predicted a maximum total settlement of 2.4 inches, reduced to 0.4 inches after initial water preloading. Water preloading was required before construction of grade-sensitive components.<br /><br />Three RIs were statically load tested to three times their design service loads. Maximum deflection at service load was 0.5 inch, and maximum test deformation was 3 inches. Production included 588 RIs installed over 18 working days, averaging 33 per day.<br /><br />Quality control included reviewing installation records for minimum diameter and length, testing grout strength, and performing low-strain pile integrity tests (PIT) on all test inclusions and 2% of production RIs. Initial PIT anomalies were attributed to installation of adjacent inclusions; additional testing indicated that curing time did not eliminate them.<br /><br />The project also included strain-gage monitoring during construction and settlement monitoring during water preloading. The presentation concludes that RIs provided an economical system that could be installed relatively quickly, with several available quality-control methods. Where lateral resistance is required, potential construction-related element breakage should be considered, along with mitigation such as reinforcement.

Keywords

rigid inclusions

Seattle project

settlement control

liquefaction settlement

Plaxis model

water preloading

load testing

pile integrity testing

quality control

strain-gage monitoring