Mandalay Bay Hotel and Casino
- Location: Las Vegas, NV
- Owner: Mandalay Resort Group
- General Contractor: Kleinfelder
- Technique(s) Utilized: Micropiles
Background
This 43-story resort structure, built on a 9-foot thick mat foundation, settled as much as 18 inches vertically down during construction, prior to occupancy. The owners needed to stop the movement or face the prospect of demolishing the unfinished building scheduled to open within the next several months. Nicholson suggested a practical scheme, working closely with the engineering team to finalize the design of 536 micropiles to stop the downward movement of the mat. Nicholson installed the piles through the existing mat foundation to depths of approximately 200 feet through interbedded layers of sand and clay deposits. The piles were installed using external flush drilling techniques.
The system was designed so that the building loads were transferred from the concrete mat foundation to the piles. A 10-foot long PVC casing was inserted into the top of the pile to prevent bonding into the mat. To complete the structural connection to the mat, each pile was constructed with its own reaction frame assembly, which included a 350-ton jack. Four steel reaction bars were grouted into the mat adjacent to each pile. The bars were attached to the reaction frame, and the jacks were extended, loading the piles. After the design load was reached, the bars were locked off with nuts to transfer the load from the mat to the piles.
Because of Nicholson’s prompt and efficient response, structural damage to the resort was prevented and the building was successfully able to open on schedule.
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