Investigation the Behaviour of Cast In-Situ Piles which are Subjected to Tension / Uplift Load with A Novel Pile Constructing / Testing Approach

Abstract

Instrumented pile loading tests can give a better understanding of the pile load -transfer mechanism. It also allows for assessing the integrity and durability issues of the bored piles under tension. When a reinforced concrete pile is subjected to high tension forces, it might reach the tensile stress capacity of concrete, and cracking occurs at the weakest section. In this study, the results of an instrumented axial static tensile pile loading test (S-KYD/& Ccedil;) were evaluated regarding crack development and propagation. It has been determined that crack development occurs when the tensile deformation capacity of the concrete is reached under the axial tensile load applied during the test. This phenomenon was observed at approximately 70-120 microStrain levels and is consistent with similar studies in the literature. With a novel approach, that prevents tensile stress development in the reinforced concrete body, the problems mentioned above are targeted to be eliminated. Dywidag-made GEWIPlus bars were used to transfer the pile head load to the pile toe. This mechanism ensures the development of compression stresses in the pile during pull-out upward loading. Loading from the pile toe contributes considerably to the load -displacement behavior of the piles that are under tension load. T & Idot;P-A and T & Idot;P-B different load application points normally don't provide a chance for direct comparison. However, for a general understanding, the comparison might be done with the Davisson Pile Capacity Estimation Method for T & Idot;P-A and T & Idot;P-B pile loading test results as per pile head loadpile head movement relations. 6.1MN for T & Idot;P-A and 8.9MN for T & Idot;P-B estimated with the Davisson Method as per pile head behavior. These figures represent a -%146 capacity increase for piles under tension load. Moreover, because the load application point is from the pile toe, comparing pile toe loadpile toe movement for TIP -B might be worthwhile. 7.3MN for TIP -B resulting -%120 capacity increase.