Ocean Engineering 292 (2024) 116498 Available online 21 December 2023 0029-8018/© 2023 Elsevier Ltd. All rights reserved. Research paper Effect of anchor geometry on uplift resistance of plate anchor in sloping terrain Mirza Mahamudul Hassan a, * , Nibir Rahman b , M.D. Rokonuzzaman b , Sayeedur Rahman c a Daffodil International University, Savar, Bangladesh b Khulna University of Engineering & Technology, Khulna, Bangladesh c D.Zingscape Professional Limited, Dhaka, Bangladesh A R T I C L E INFO Handling Editor: Prof. A.I. Incecik Keywords: Plate anchors Uplift capacity Sloping ground Breakout factor Soil failure mechanism PLAXIS 3D ABSTRACT Plate anchors are employed in various applications, including offshore constructions, mooring systems, trans- mission towers, etc., to counteract uplift forces caused by outwardly directed loads above or below the ground. Relatively limited focus has been directed towards the uplift capacity of plate anchors on purely frictional sloping terrain, especially regarding the impact of various anchor shapes. The study investigates the effect of anchor geometry, slope inclination, internal friction angles, and embedment ratios on anchor uplift capacity through a rigorous three-dimensional finite element model using PLAXIS 3D. Several numerical and experimental studies have been compared to the current findings to validate the model. The findings show that the anchor geometry and the steepness of the slope significantly impact an anchor’s uplift capacity. The uplift capacity is represented in terms of the nondimensional break-out factor. Breakout factors decrease with the increase of anchor length-to- width ratios and slope inclination angles. Moreover, the study demonstrates how the inclination angle of a slope affects the failure mechanisms. In addition, the shape factor is introduced to evaluate further how anchor ge- ometry affects pullout capacity. To evaluate the effect of shape variations and slope inclinations, the study provides mathematical equations that allow precise predictions of anchor uplift capability. 1. Introduction Offshore structures, mooring systems, bulkheads, transmission towers, and other structures are subject to uplift forces caused by lateral forces above or below the ground surface. Due to their effectiveness in resisting uplift forces, plate anchors are frequently employed as the primary foundation element for such structures. Over the last few decades, several researchers have conducted extensive research on plate anchors. Numerous experimental and nu- merical studies have been carried out in order to assess the uplift ca- pacity of plate anchors buried in frictional soil. Before the study of Balla (1961), the failure mechanism was assumed, and the mass of soil above the anchor was considered in equilibrium within the confines of the aforementioned failure surface. Most researchers suggested it as a way to measure the anchor’s uplift capacity. In the following years, several experimental investigations were conducted by several researchers to assess the ultimate uplift load of plate anchors, with centrifuge tests and traditional methods under “normal gravity” conditions being the most prevalent (Das and Seeley, 1975; Rowe, 1978; Murray and Geddes, 1987; Dickin, 1988; Frydman and Shaham, 1989; Ilamparuthi and Muthukrishnaiah, 1999; Ilamparuthi et al., 2002; Singh and Ram- aswamy, 2008; Rokonuzzaman and Sakai, 2012a; O’Loughlin et al., 2014; Choudhary and Dash, 2017). In contrast, a limited number of numerical investigations have been undertaken to compute the uplift capacity of plate anchors. Meyerhof and Adams (1968) provided a partly empirical theory for approximating the maximum uplift load of hori- zontally buried strip, rectangular, and circular anchors. Multiple re- searchers have used the limit equilibrium technique to calculate the anchor’s uplift capacity (Murray and Geddes, 1987; Saeedy, 1987; Ghaly and Hanna, 1994). The limit equilibrium approach assumes a log-spiral failure surface. It uses Kotter’s equation (Balla, 1961) or a prediction considering the direction of forces exerted on the failure surface to derive the stress distribution. To examine the impact of the anchor’s length-width ratio on the ultimate uplift load, Murray and Geddes (1987) conducted both laboratory experiments and limit analyses. Ac- cording to the findings of their investigation, the ultimate uplift capacity * Corresponding author. E-mail addresses: mirzamahamudulhassan@gmail.com (M.M. Hassan), nibir@ce.kuet.ac.bd (N. Rahman), rokon@ce.kuet.ac.bd (M.D. Rokonuzzaman), sayeedur@dzingscape.net (S. Rahman). Contents lists available at ScienceDirect Ocean Engineering journal homepage: www.elsevier.com/locate/oceaneng https://doi.org/10.1016/j.oceaneng.2023.116498 Received 16 September 2023; Received in revised form 16 November 2023; Accepted 1 December 2023