Evaluation of p-y Curves for Group Piles in Cohesive Soil Based on 3D Numerical Analysis

The pile foundation supported on a structure can generate large horizontal loads due to earthquakes, high winds, and wave actions. The behavior of piles when subjected to horizontal load is generally analyzed using the p-y curve and “p-multiplier (Pm),” which is the coefficient of the group pile effect. In this study, the p-y curves and Pm were calculated by analyzing a single pile and group of piles arranged in 3 × 3 installed in cohesive soil using the finite element analysis program, Plaxis 3D. The soil resistance (p) increased as the undrained shear strength of the clay increased and the distance between the pile centers (S/D) increased. In the case of the group pile effect, when Pm was closer to the center of the group pile, the distance between the pile centers was smaller, and Pm was less due to the interference effect of the adjacent individual piles. In conclusion, it was observed that Pm is affected by the location of the individual piles and the distance between the pile centers.

Energy-Based Approach for the Analysis of a Vertically Loaded Pile in Multi-layered Non-linear Soil Strata

Numerous studies have been reported in published literature on analytical solutions for a vertically loaded pile installed in a homogeneous single soil layer. However, piles are rarely installed in an ideal homogeneous single soil layer. This study presents an energy-based approach to obtain displacements in an axially loaded pile embedded in multi-layered soil considering soil non-linearity. A simple power law based on published literature is used where the soil is assumed to be nonlinear-elastic and perfectly plastic. A Tresca yield surface is assumed to develop the soil stiffness variation with different strain levels that defines the non-linearity of the soil strata. The pile displacement response is obtained using the software MATLAB R2019a and the results from the energy-based method are compared with those obtained from the field test data as well as the finite element analysis based on the software ANSYS 2019R3. It is observed that the results obtained from the energy-based method are in better agreement with the field measured values than those obtained from the FEA. The approach presented in this study can be extended to piles embedded in multi-layered soil strata subjected to different cases of lateral loads as well as the combined action of lateral and axial loads. Furthermore, the same approach can be extended to study the response of the soil to group piles.

Soil-Structure Interaction Study on Group pile over Monopile Foundation

Soil structures are very important for very good strength and durability to the reinforced concrete structures. it is extensively used for bridges, turbines, dams, industrial structures, and other heavy structures. soil-structure interactions are extensively used for seismic responses to the structures. it is mostly used in geotechnical investigations on pile foundations. The main importance of soil-structure interaction is the response of soil and structure and it influences the motion of ground and motion of the structure. It is one of the important factors to know the interactions between the soil and the ground. If the soil interactions are good, then the structure will be safe and strong and withstand the seismic effects. So, the study of soil interaction is important for any structure for safety and serviceability conditions. This paper mainly focuses on group piles over the monopile foundation of soil interaction. This mainly explains the importance of a monopile foundation over the group pile foundation. Monopile foundation is simple to type construction and standard foundation nowadays. This paper is mainly focused on soil structure and its interaction and as well monopile foundation and its importance.

STABILITAS TIANG PANCANG AKIBAT LIKUIFAKSI PADA PROYEK GEDUNG SANGGALA JAKARTA

Liquefaction is an incident where the soil losses its shear strength due to increased porewater stress due to the incident of very fast cyclic loading in a short time. Liquefaction event due to earthquakes can cause structural failure of the building. In this case, the Sanggala Building Project in Jakarta exists at location of liquefaction potential susceptible area, and design analysis only uses the data of Cone Penetration Test (CPT). Stability analysis of pile due to liquefaction potential is aimed to determine the value of the factor of safety (FS) in the area, which is analyzed by comparing the value of Cyclic Stress Ratio (CSR) due to the earthquake and Cyclic Resistance Ratio (CRR) as the soil resistance to resist liquefaction potential. Based on the analysis and calculations performed, was obtained the value of FS > 1, which means actually the soil does not have the liquefaction potential. However, this study still takes into consideration the liquefaction potential as one of requirements of local regulation when the analysis of bearing capacity of pile foundation analyzed by the method of Schmertmann (1978) in a depth of 25 m and the results was indicated by 1660,27 kN for single pile and 12081,63 kN for the group piles. Furthermore, all these results from several stability calculations, the pile foundation system stable from liquefaction potential.

ANALISIS DEFORMASI LATERAL GRUP PONDASI TIANG DENGAN PERKUATAN MENGGUNAKAN TIANG MIRING (BATTER PILES) PADA JEMBATAN DERMAGA

ABSTRACT: Lateral deformation of group piles foundation is one of the parameters that must be considered properly, excessive lateral deformation can cause damage to the structure. In bridge structures, cases of excessive lateral deformation often occur which potentially affect the reliability of the bridge and cause damage to the structure. When the lateral deformation that occurs in the foundation group exceeds the safety limit, it needs additional reinforcement designed to provide additional lateral resistance, so that the deformation that occurs can be reduced and the strength of the structure also increases. Reinforcement using inclined piles (batter piles) can be used in increasing the lateral resistance of the group piles foundation. The use of batter piles mechanically distributes the horizontal load to the vertical direction of the foundation, so that the lateral load that carried by the foundation is distributed into vertical and horizontal components, to reduce the lateral deformation that occurs. In this study, the lateral deformation analysis was carried out on the group piles foundation on the jetty bridge which experienced a large deformation, then a reinforcement design was designed using batter piles to increase lateral resistance. The analysis was performed using PLAXIS 2D and GROUP software. From the analysis, it was found that reinforcement using batter piles can reduce the lateral deformation that occurs and increase the stability of the bridge..Keywords: batter piles, lateral deformation, lateral resistance

Static loading tests on small-scale pile groups

36 small-scale model tests in soft clay were conducted to research the performances of pile groups under rigid caps. The parameters studied were the effect of pile length, pile spacing, and the number of piles in a group. The group piles consisted of 4, 6, and 9 circular model piles of 16mm in outer diameter (D), while four kinds of the pile spacing between pile centers 3; 4; 5; and 6 times of the diameter and three types of the embedded pile lengths: 20D; 25D; and 30D were used. For comparison, three single piles with the same diameter and length were also tested under the same condition. The experimental results were discussed based on the following 3 points of view: the pile group efficiency, the settlement ratio, load distribution per pile location in the group pile. All discussion suggested that the pile number and pile spacing in a pile group caused a remarkable interactional effect between piles, whereas the settlement ratios are significantly affected by the pile length. Besides, each pile in the group of 6D pile spacing behaved more individually.

Analisis Kapasitas Lateral Pada Fondasi Tiang Tunggal Dan Tiang Kelompok Pada Tanah Pasir

Fondasi ialah bagian dari suatu sistem rekayasa yang meneruskan beban yang ditopang oleh fondasi dan beratnya sendiri kedalam tanah dan batuan yang terletak dibawahnya. Pada jurnal ini, dilakukan analisa kapasitas lateral tiang tunggal dan tiang kelompok pada tanah pasir. Untuk dapat menganalisis tiang pancang tunggal dan tiang kelompok pada tanah pasir dalam kondisi elastic dapat dilakukan dengan metode analisis statik non linier atau analisis pushover. Analisis pushover adalah prosedur analisis untuk mengetahui keruntuhan suatu bangunan dengan memberikan suatu pola beban statik tertentu dalam arah lateral yang besarnya akan ditingkatkan secara bertahap sampai struktur tersebut mencapai target displacement tertentu atau mencapai pola keruntuhan tertentu. Dari hasil analisis pushover terhadap suatu tiang dihasilkan kurva yang menghubungkan antara base shear dan roof displacement atau disebut kurva kapasitas. Dari kurva kapasitas tersebut dapat dilihat perilaku suatu tiang dari kondisi elastis sampai plastis hingga mengalami kegagalan. Dengan adanya kurva kapasitas yang diperoleh, kita dapat melihat tingkat kinerja suatu tiang berdasarkan metode spektrum kapasitas berdasarkan peraturan ATC-40 dan Pushover Analysis of Underground Structures. The foundation is part of an engineering system that forwards the burden supported by the foundation and its own weight into the soil and rocks beneath. In this journal, an analysis of the lateral capacity of single piles and group piles is carried out on sandy soil. To be able to analyze a single pile and group piles on sandy soil in elastic conditions can be done by non-linear static analysis or pushover analysis. Pushover analysis is an analysis procedure to determine the collapse of a building by providing a certain static load pattern in the lateral direction whose magnitude will be increased gradually until the structure reaches a certain displacement target or reaches a certain collapse pattern. From the results of pushover analysis on a pile, a curve that connects the base shear and roof displacement is called a capacity curve. From the capacity curve, it can be seen the behavior of a pile from elastic to plastic conditions to failure. With the obtained capacity curve, we can see the level of performance of a pile based on the capacity spectrum method based on ATC-40 regulations and Pushover Analysis of Underground Structures.