Behaviour of Laterally Loaded Piles

Pile foundations are often subject to lateral loads and axial loads. Although design methods for axial loading are well developed, lateral loading cases have attracted more attention recently following reported case histories of piles damaged during earthquakes. In this work, pile design due to lateral loading in tuff soils is considered. Pile deflections, bending moment and rotation were analyzed with OpenSeesPL program, a 3D finite element tool. OpenSeesPL is used to model the properties of the piles which are embedded in tuff and laterally load tested in Izmir. The displacement calculated by OpenSeesPL of 2.25mm is close to the measured 2.5mm. In this study, influence of pile length was investigated. From the results, it was observed that as the pile length increased from 6m to 20.5m, the movement, displacement and the rotation of the pile has decreased. In addition, with the same program, lateral displacement of a single pile in sandy and clayey soil layers were also analyzed with the results summarized. In all types of soils, as the pile length has decreased, the pile displacement has increased. INTRODUCTION Pile foundations are often subject to lateral loads and axial loads. Although design methods for axial loading are well developed, lateral loading cases have attracted more attention recently following reported case histories of piles damaged during earthquakes. In this work, pile design due to lateral loading in tuff soils is considered. Pile deflections, bending moment, and rotation were analyzed with OpenSeesPL program, a 3D finite element tool. Under lateral load, the pile is subjected to bending moment and shear, and the behavior of its cross section is a major component of the pile response. The design of piles for use against lateral loads is usually governed by the maximum tolerable deflection (Poulos and Davis 1990). Load-deflection responses of laterally loaded piles depend on many factors, such as pile dimensions, structural material properties, nearby soil conditions; lateral spreading, soil-structure interaction and type of loadings. OpenSeesPL is used to model the properties of the piles which are embedded in tuff and laterally load tested in Izmir. The displacement calculated by OpenSeesPL of 2.25mm is close to the measured 2.5mm. In this study, influence of pile length was investigated. Lateral displacement of a single pile in sandy and clayey soil layers was also analyzed. SITE CONDITION A 140000 m 3 capacity tank was planned to be constructed in Izmir in 2001. Axial and lateral loading tests were conducted on the 120cm diameter bored piles proposed for use in supporting the tank. The soil investigation consisted of four boreholes. Two boreholes were drilled during the first exploration and two boreholes were drilled after the tank site was filled. The soil profile is shown in Fig. 1 and is as follows: (Sekerer, 2009): Fill having a thickness of 7.5-9.0m 30  =3-50 Organic Mud (silt+sand) having a thickness 2.5-4.0m 30  =1-2 (before the construction of fill) 30  =4-16 (under the fill load) Tuff ANALYSIS AND NUMERICAL SIMULATION In the OpenSeesPL program; pile geometry, material properties, boundary conditions and input excitation are defined. Representative soil properties are given for soils in Table 1.