INFLUENCE OF A ROUND CAP ON THE BEARING CAPACITY OF A LATERALLY LOADED PILE

Vestnik MGSU 4/2012
  • Buslov Anatoliy Semenovich - Gersevanov Research Institute of Bases and Underground Structures (NIIOSP) Doctor of Technical Science, Professor, Advisor Russian Academy of Architecture and Construction Sciences, chief research worker, Gersevanov Research Institute of Bases and Underground Structures (NIIOSP), 59 Ryazanskiy pr-t, Moscow, 109428, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Bakulina Aleksandra Aleksandrovna - Ryazan' Branch, Moscow State Open University named after V.S. Chernomyrdin , Ryazan' Branch, Moscow State Open University named after V.S. Chernomyrdin, 26/53 Pravo-Lybedskaya St., 390000, Ryazan', Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 63 - 68

Foundations of laterally loaded single piles are widely used as part of power transmission lines, wind power stations, highway structures, etc. Ongoing pressure applied to a laterally loaded pile, particularly at the ground level, causes the soil deformation characterized by the bulging of the soil surface.
In the majority of cases, the deformation strength of a pile depends on the front-face soil resistance, Horizontal beams, ground caps or rigid plates are used to increase the pile resistance. An effective method of pressure reduction contemplates the use of a rigid round cap at the front-face or upper level of the soil.
In this paper, the authors analyse the data to examine how a round cap installed at the ground level impacts the bearing capacity of a single pile.
This research based on the methodology developed by the authors demonstrates that a laterally loaded pile, supported by a rigid cap at the ground level, is exposed to increased resistance due to the following factors, including the passive pressure along the cap side that creates an unloading effect for a horizontally-loaded pile. The cap acts as a vertical soil rebuff creating an additional resistance moment; the horizontal shear of the cap causes supplementary lateral resistance of a pile.
The following initial geometric and elastic material properties of the single pile are applied: total length = 5.0 meters (3.0 m above and 2.0 m below the ground surface); pile diameter = 40 centimeters; circle plates of various diameters = 60; 70; 80 and 100 cm and their thickness = 20 cm. A lateral load is applied at various heights, , of 0.2; 1.0; 2.0 and 3.0 meters above the ground level.
Elastic properties of the soil are assumed to be constant at each point below the surface of the ground, they are listed below: bulk modulus of soil E=20 MPa; Poisson's ratio μ=0,37; unit Weight γ=18,5 kN/m; cohesion =0,05 MPa; angle of internal friction φ=20°.
The data has proven that cap-covered piles are substantially more economical (over 40 %) in terms of materials consumption rate if compared to constant cross-section piles (cap-free or broadening piles), all other factors being equal.

DOI: 10.22227/1997-0935.2012.4.63 - 68

References
  1. Normy proektirovaniya kontaktnoy seti [Overhead Contact System Design Standards]. 141-99. MPS RF. Moscow, 2001.
  2. Matus N.Yu. K raschetu gorizontal'no nagruzhennoy svai-kolonny s nizkim rostverkomogolovkom [About the Design of a Laterally Loaded Pile-Column with Deep Grid Pile Foundation]. OOO HT Project — Ukraina, Odessa, 8 p.
  3. Buslov A.S., Tulakov E.S. Raschet gorizontal'no nagruzhennykh odnostoechnykh opor po ustoychivosti [Stability Design of Laterally Loaded Single Footings]. Osnovaniya, fundamenty i mekhanika gruntov [Beddings, Foundations, and Soil Mechanics]. Moscow, 2004, no. 3, pp. 6—9.

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CALCULATION OF DISPLACEMENTS OF LATERALLY LOADED PILES WITH ROUND CAPS WITHIN THE LIMITS OF LINEAR DEFORMATIONS OF THE BASE

Vestnik MGSU 11/2012
  • Buslov Anatoliy Semenovich - Moscow State Open University named after V.S. Chernomyrdin (MGOU) Doctor of Technical Sciences, Professor, Chair, Department of Construction Operations, Beddings and Foundations +7 (495) 683-87-97, Moscow State Open University named after V.S. Chernomyrdin (MGOU), 22 Korchagina st., Moscow, 129626, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Bakulina Aleksandra Aleksandrovna - Ryazan' Branch, Moscow State Open University named after V.S. Chernomyrdin , Ryazan' Branch, Moscow State Open University named after V.S. Chernomyrdin, 26/53 Pravo-Lybedskaya St., 390000, Ryazan', Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 38 - 44

The authors provide data on the influence of a round cap installed in the upper compressed
zone of soil onto displacement of laterally loaded single-pile supports identified on the basis of the
analytical method that they have developed. The authors demonstrate that both the front surface of
the round cap and its bottom contribute to formation of the supplementary resistance to displacements
of a laterally loaded pile due to (i) the friction force that arises alongside its contact with soil
in the event of a lateral displacement, and (ii) a vertical pressure under the impact of a moment load
in the event of a tilted slab. A round cap in the upper displaced zone of soil may cause a substantial
reduction (4-8-fold) of displacements of a laterally loaded pile if compared to the pile that has no
round cap.

DOI: 10.22227/1997-0935.2012.11.38 - 44

References
  1. Bakulina A.A., Buslov A.S. Issledovanie MKE napryazhenno-deformirovannogo i silovogo vzaimodeystviya fundamentov odnostoechnykh gorizontal’no nagruzhennykh opor s uprugim poluprostranstvom [Research of the Stress-stain and Force Interaction of Foundations of Single-column Laterally Loaded Supports with an Elastic Half-space Using FEM]. Collected works of the Institute of Construction and Architecture. Collected papers of the International Scientific and Technical Conference “Promyshlennoe i grazhdanskoe stroitel’stvo v sovremennykh usloviyakh” [Industrial and Civil Engineering in the Present-day Environment]. Moscow, MGSU Publ., 2011, pp. 135—137.
  2. Buslov A.S. Rabota svay na gorizontal’nuyu nagruzku za predelami uprugosti v svyaznykh gruntakh [Behaviour of Piles Exposed to Lateral Load beyond the Limits of Elasticity in Cohesive Soils]. Tashkent, Fan Publ., 1979, 106 p.
  3. Broms B.B. Lateral Resistance of Piles in Cohesive Soils. J. Soil Mech. Found. Div. 1964, no. 90(2), pp. 27—64.
  4. Tsytovich N.A., Veselov V.A., Kuz’min P.G.; edited by Tsytovich N.A. Osnovaniya i fundamenty [Beddings and Foundations]. Moscow, Gos. izd-vo literatury po stroitel’stvu, arkhitekture i stroitel’nym materialam publ., 1959, 452 p.
  5. Buslov A.S., Bakulina A.A. Vliyanie kol’tsevogo ushireniya na nesushchuyu sposobnost’ gorizontal’no nagruzhennoy monosvaynoy opory [Effect of a Round Cap on the Bearing Capacity of a Laterally Loaded Pile]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering], 2012, no. 4, pp. 63—69.

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