engleski

3D FE analysis of anchor bolts with large embedment depths

In the present paper results of the finite element study for headed stud anchors loaded in tension (concrete cone failure) are presented and discussed. Considered are anchors with extremely large embedment depths (up to 1143 mm) and with relatively large heads. Many of such anchors were used in the past, especially in the nuclear power plants. The aim of the study was to investigate their behaviour more closely. Some recent test results indicate that the ultimate tension resistance of single anchors and anchor groups with larger anchor head sizes is greater than proposed in the current design recommendation, which is based on linear elastic fracture mechanics. Furthermore, the tests have shown that in the case of headed studs with large heads the concrete cone propagates somewhat flatter than in the case of fastenings with smaller heads. The numerical analysis was performed using a 3D finite element code based on the microplane model. Ultimate tension resistance of single anchors was investigated for different embedment depths. For each embedment depth the size of the head of the anchor was varied in order to account for the influence of pressures under the anchor head. Furthermore, for the anchor group of four anchors, the influence of the head size on the characteristic spacing of anchors was investigated. The results of the finite element study are discussed and compared with the recently performed test results and with current code recommendations.

Anchor bolts; Concrete cone failure; Size effect; Finite elements; Microplane model

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