Session Start Date

6-1-1988

Abstract

A specialty contractor installed high-capacity pressure-injected footings (PIFs) for foundations in a congested area of an existing coal-fired power plant. Some concrete cylinders broke at strengths significantly lower than the minimum specified strength. Initial coring of some of the PIFs uncovered voids and deleterious matter at the junction of the shaft and the end-bearing base of the PIFs. Subsequent load tests and additional coring substantiated the load-transfer problem. A field testing program was initiated to verify the load-carrying capacity of all the completed PIFs. Wave equation analyses optimized the testing program, established the field testing criteria, and predicted ultimate capacities close to the measured capacities determined from load tests. Load tests also verified the design equation used to control installation of the foundation units. Field testing increased the overall average factor of safety with respect to ultimate capacity.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Second Conference

Publisher

University of Missouri--Rolla

Publication Date

6-1-1988

Document Version

Final Version

Rights

© 1988 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Jun 1st, 12:00 AM

Pressure Injected Footings – A Case History

A specialty contractor installed high-capacity pressure-injected footings (PIFs) for foundations in a congested area of an existing coal-fired power plant. Some concrete cylinders broke at strengths significantly lower than the minimum specified strength. Initial coring of some of the PIFs uncovered voids and deleterious matter at the junction of the shaft and the end-bearing base of the PIFs. Subsequent load tests and additional coring substantiated the load-transfer problem. A field testing program was initiated to verify the load-carrying capacity of all the completed PIFs. Wave equation analyses optimized the testing program, established the field testing criteria, and predicted ultimate capacities close to the measured capacities determined from load tests. Load tests also verified the design equation used to control installation of the foundation units. Field testing increased the overall average factor of safety with respect to ultimate capacity.