Excessive Pile Breakage, Gaylord National Resort and Conference Center, a Look Back 15 Years Later-PPT Presentation

PPT Presentation

Pdf Summary

Karl A. Higgins’s presentation reviews pile breakage during construction of the Gaylord National Resort and Convention Center, which used approximately 150,000 linear feet of driven, precast concrete piles. The site crossed an abrupt geological transition, and the project adopted 14-inch-square, prestressed piles designed for 150-ton capacity after test-pile driving and dynamic testing.<br /><br />Test piles performed relatively well, with only one reported break among 17. However, about six weeks into production, crews encountered frequent pile-head damage and below-grade breaks, causing schedule concerns. Forensic work examined cores from three broken production piles and one undamaged test pile. The production-pile concrete included fly ash and ground-granulated blast-furnace slag, while the test pile used 100% Portland cement. The presentation notes that these cement substitutes can reduce early-age compressive strength. Core results also showed substantial variation in production-pile strengths, and some samples were below the specified 6,000 psi strength.<br /><br />Project specifications allowed cement substitutes, and the mix design was not changed after the investigation identified a likely connection. The presenter concludes that pile specifications should require 100% Portland cement and full design strength by seven days, supported by project-specific trial batches before test driving. He also recommends independent laboratory testing of all supplied concrete, regardless of manufacturer certification.<br /><br />The adjacent National Harbor development later used the same pile type with revised concrete requirements. Despite retaining the hammer specifications, it experienced far fewer damaged piles. This experience reinforced the importance of concrete mix composition, early-age strength verification, and independent quality control in driven-pile projects.

Keywords

pile breakage

driven precast concrete piles

Gaylord National Resort

prestressed piles

dynamic testing

pile-head damage

fly ash

ground-granulated blast-furnace slag

early-age strength

independent quality control