Vertical Uplift Capacity of a Group of Helical Screw Anchors in Sand
Tóm tắt
In this paper experimental investigations on the behavior of single, double and triple helical screw anchors under the influence of vertical uplift loads are presented. The testing program was conducted on three model anchors having single, double and triple helical screws installed in sand. The experimental setup was instrumented to measure the pullout load and the upward displacement of the anchor. It was observed that the pullout load varied significantly with the installation depth of the anchor and the number of anchors. A mathematical model was developed using the limit-equilibrium method of analysis. Based on experimental results, non-dimensional graphs were plotted normalizing the deformation and load axis both and simple equations are proposed correlating load and deformation. Using these equations an anchor foundation for a particular structure can be designed. Comparison of the pullout load values obtained from the theory developed and the present experimental results showed good agreement.
Tài liệu tham khảo
Adams JI, Hayes DC (1967) The uplift capacity of shallow foundations. Ont Hydro Res Q 19(1):1–13
Meyerhof GG, Adams JI (1968) The ultimate uplift capacity of foundations. Can Geotech J 5(4):224–244
Meyerhof GG (1973) Uplift resistance of inclined anchors and piles, vol 2. In: Proceedings of 8th ICSMFE, pp 167–172
Radhakrishna KS (1976) ‘Helix anchor tests in sand’, Ontario Hydro Research Division, Research Report, 76–130K, pp 1–33
Udwari JJ, Rodgers TE, Singh H (1979) A rational approach to the design of high capacity multi helix screw anchors. In: Proceedings of the 7th IEEE/PES, transmission and distribution Conference and Exposition, 600–610, New York, USA
Mitsch MP, Clemence SP (1985) The uplift capacity of helix anchors in sand: uplift behavior of anchor foundation in soil. In: Proceedings ASCE New York, pp 26–47
Merifield RS, Smith CC (2010) The ultimate uplift capacity of multiplate strip anchors in undrained clay. Comput Geotech 37(4):504–514
Ghaly AM, Hanna AM (1991) Uplift behavior of screw anchors in sand 1: dry sand. J Geotech Eng ASCE 117(5):773–793
Mittal S, Shekhar S, Ganjoo B (2010) Static Equilibrium of screw anchor pile under lateral load in sands. Geotech Geol Eng 28:717–725
Kumar J, Khatri VN (2011) Effect of anchor width on pullout capacity of strip anchors in sand. Can Geotech J 48(3):511–517
Merifield RS (2011) Ultimate uplift capacity of multi plate helical type anchors in clay. J Geotech Eng ASCE 137(7):704–716
Ghaly AM, Hanna AM (1991) Experimental and theoretical studies on installation torque of screw anchors. Can Geotech J 28(2):353–364
Douglas DJ, Davis EH (1964) The movement of buried footings due to movement and horizontal load and the movement of anchor plates. Geotechnique 14(2):115–132
Fox EN (1948) The mean elastic settlement of a uniformly loaded area at a depth below the ground surface. In: Proceedings 2nd international conference on soil mechanics, Rotterdam 1, p 29
Rowe RK, Booker JR (1979) A method of analysis for horizontal anchors in a elastic soil. Int J Numer Anal Methods Geomech 3(2):187–203
Balla A (1961) The resistance to breaking out of mushroom foundations for pylons. In: Proceedings 5th international conference on soil mechanics, Paris 1, pp 569–576
Neely WJ, Stewart JG, Graham J (1973) Failure loads of vertical anchor plates in sand. J Geotech Eng ASCE 99(9):669–685
Ovesen NK, Stroman H (1972) Design methods for vertical anchor plates in sand. In: Proceedings of speciality conference on performance of earth at earth supported structures. ASCE New York, pp 1481–1500
Vesic AS (1971) Breakout resistance of objects embedded in ocean bottom. J Soil Mech Found Div ASCE 97(9):1185–1205
Mittal S (2013) An introduction to ground improvement engineering. Scientific International Publications Ltd., New Delhi
Mittal S, Shukla JP (2009) Soil testing for engineers. Khanna Publishers, India
Malik R (2007) Performance study of anchor piles in sand. Dissertation, IIT Roorkee