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Título

A Case Study in Which a 50cm-Diameter CFA Pile Showed Low Capacity in the Dynamic Load Test

Palavras-chave

Dynamic Increasing Energy Test, CFA Piles, Low Capacity, Quality Assurance, Deep Foundations, Small Project Sites

Resumo (no máximo 200 palavras)

The Dynamic Load Test (DLT) has been used worldwide due to speed and economy. Many authors have shown good correlations between static and dynamic tests. Moreover, dynamic data collected by the Pile Driving Analyzer (PDA) may be further analyzed by the signal-matching method to evaluate the soil resistance distribution, toe resistance, quakes, and damping. The CAPWAP is a software commonly used to perform the signal-matching method. In this case study, the piles were designed to support 280kN, and 50cm-diameter CFA piles were installed between 4.9m and 7.0m in depth. In addition, the soil profile indicated sandy clay soil, followed by clayey silt soil. Although it was not mandatory according to the Brazilian specifications (NBR 6122:2022), the contractor requested to test four piles through the DLT, and the final sets were between 5.0mm and 8.0mm, which indicates that the piles reached the ultimate load. The CAPWAP analysis showed that the pile E01 (4.9m depth) obtained only 246kN, lower than the design load. However, piles E12 (5.1m depth) and E25 (5.1m depth) reached 680kN and 643kN, respectively. The longest pile (E35, 7.0m depth) obtained 553kN. This paper shows the need for quality assurance of the deep foundations, even in small project sites.

Palavras Chave

CFA Piles; Deep Foundations; Dynamic Increasing Energy Test; Low Capacity; Quality Assurance; Small Project Sites

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