Research on Method of Non-Linear Static Pushover Analysis and Influential Mechanism of Displacement Ductility of Single Pile

2012 ◽  
Vol 204-208 ◽  
pp. 990-994
Author(s):  
Xing Chong Chen ◽  
Xue Lin Yue ◽  
Yong Liang Zhang

In this article, the distribution of plastic hinge model is adopted to simulate the elastic and plastic of pile body, p-y curve is used to simulate resistance of pile foundation soil. We do static non-linear pushover analysis of the single pile of pile foundations, and research the influence of the axial compressive ratio η of pile shaft, longitudinal reinforcement rate ρ of section, stirrup ratio µof section and shear strength C of foundation soil to the system-interaction of pile and soil. The result shows that axial compressive ratio of pile shaft has a significant influence on horizontal limit bearing capacity and the displacement ductility of the system. With the increase of the axial compressive ratio, system of the displacement ductility reduces gradually, but the limit bearing capacity increases gradually. Under a horizontal load, the order and the mechanism of plastic hinge are obviously different because of different axial compressive ratio of pile shaft,This analysis method may further provide a reference for nonlinear seismic analysis of pile bents.

Author(s):  
Suraj Raut

An earthquake structures are mandatory to avoid significant damages (i.e., collapse) and aims that structure withstand a major earthquake without collapse. The design approach adopted is to ensure that the columns of the structure more capable to resist moments than beam; to avoid progressive collapse of structure due to failure of columns in lower level; it is necessary the columns have stronger than beams (strong column weak beam). The concept of SCWB is to ensure that plastic hinge formed in the beam not in the column; this help in dissipating the more energy along with providing ductility to the structure. If the plastic hinge is formed on the both ends of column then, the column is not able to spread the plasticity and collapse which are leads to global failure. The failure modes in all past earthquake is exactly opposite i.e, strong beam weak column; and comes to sway mechanism and fails to collapse. For this it is foreseen that the values of ratio of Mc/Mb (ratio of sum of ultimate moment of resistance of columns to sum of ultimate moment of resistance of beam) in the beam-column joint are stated by many design codes and the values are different ranging from 1.2,1.3,1.4,1.5 to 2, etc. Another effect of ratio Ic/Ib (ratio of moment of inertia of column to moment of inertia of beam) have been studied but the exact meeting of SCWB behaviour in the structures at the time of collapse not stated clearly. The Mc/Mb and Ic/Ib ratio are very important to prevent damage in the structure under seismic action. In the present work, attempts are made to achieve exact ratio of exact strong column weak beam. In this study, the combined effect of two ratio (Mc/Mb, Ic/Ib) simultaneously investigated in different zones of India to find out exact SCWB ratio’s value for to meet the SCWB behaviour. Different numerical examples are presented of combine ratios (Mc/Mb,Ic/Ib) and pushover analysis is performed on each ratio’s. The result of the investigation highlighted on the objective that is to find exact SCWB ratio value considering the parameter like target displacement, ductility ratio, hinge response etc.


Seismic analysis is considered as an important parameter for any structural design. The strength and ductility of frame members in seismic design depends on the response reduction factor. In this paper four symmetrically framed structures are considered of different heights under the critical zone condition. The primary emphases of this work is regarding calculation of response reduction factor values attained from designing RC framed structures. The results are computed by applying non-linear static pushover analysis. SAP-2000 software is used for analyzing the non-linear behaviour of the structure.


2005 ◽  
Vol 21 (4) ◽  
pp. 1027-1041 ◽  
Author(s):  
Rakesh K. Goel ◽  
Anil K. Chopra

The role of higher-“mode” pushover analyses in seismic analysis of buildings is examined in this paper. It is demonstrated that the higher-“mode” pushover curves reveal plastic hinge mechanisms that are not detected by the first-“mode” or other FEMA-356 force distributions, but these purely local mechanisms are not likely to develop during realistic ground motions in an otherwise regular building without a soft and/or weak story. Furthermore, the conditions necessary for “reversal” of a higher-“mode” pushover curve are examined. It is shown that “reversal” in a higher-“mode” pushover curve occurs after formation of a mechanism if the resultant force above the bottom of the mechanism is in the direction that moves the roof in a direction opposite to that prior to formation of the mechanism. Such “reversal” can occur only in higher-“mode” pushover analyses but not in the pushover analyses for the first-“mode” or other FEMA-356 force distributions. However, the “reversal” in higher-“mode” pushover curves was found to be very rare in several recent investigations that examined behavior of many moment-resisting frame buildings. Included are guidelines for implementing the Modal Pushover Analysis for buildings that display “reversal” in a higher-“mode” pushover curve.


2014 ◽  
Vol 1065-1069 ◽  
pp. 943-948
Author(s):  
Zhi Meng Zhao ◽  
Jin Yi Chai ◽  
Cai Xia Fan

The effects of pile diameter, the property of pile end bearing stratum, the material parameters of pile shaft and the changes of pile length on the bearing performance of extra-long and large-diameter single pile were examined with the finite element software ABAQUS to make the numerical simulation analysis, by establishing the overall axial symmetry model, which was based on the data of static load test of single pile at the Yellow River Bridge site. The results show that the ultimate bearing capacity of single pile, the stiffness and the end resistance ratio would increase gradually, whereas the compression settlement ratio decreases slowly; the pile end grouting can significantly increase the ultimate loads, and therefore, improve the bearing performance of piles, but it has little effect on the stiffness of pile when loading was smaller; the elastic modulus of pile shaft has no effect on the ultimate bearing capacity of friction piles, little on the end resistance ratio, while the pile compression settlement ratio would gradually decrease and the stiffness would increased with the increase of the elastic modulus of pile shaft, and this increase of stiffness would slow down with the increase of elastic modulus of pile shaft; it is unreasonable to improve the ultimate bearing capacity of extra-long single pile only by means of increasing the pile length.


2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jing-Bo Su ◽  
Zheng-yang Yu ◽  
Ya-Ru Lv ◽  
Yi-Huan Zhu ◽  
Hua-Qing Wang

This paper addresses the problem of open gaps caused by differential settlement in the process of constructing sluice buildings in soft soil beach areas, combined with the construction of sluice and supporting facilities in a reclamation project. First, the change rules for the shear strength and compression modulus of soft soil under different consolidation degrees are studied by theoretical analysis. Then, an interaction model for soft soil and pile soil is established using the geotechnical finite element analysis software MIDAS/GTS NX. The change rules for the vertical and horizontal ultimate bearing capacities of a single pile with the degree of soil consolidation are studied. On this basis, a three-dimensional numerical analysis model of drainage sluice, seawall, cofferdam, and foundation soil is established, and the relationship between the degree of soil consolidation and the development of structural gaps caused by differential settlement is obtained. The research results show that the bearing capacity of a single pile increases greatly with the consolidation of soil around the pile and that the gap width between the structures in the project decreases with increasing consolidation. This paper provides a theoretical basis for the prediction of pile bearing capacity in the preliminary design stage and the evaluation and calculation of differential settlement of intersecting buildings in soft soil beach areas.


2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Nidiasari Jati Sunaryati Eem Ikhsan

Struktur rangka baja pemikul momen merupakan jenis struktur baja tahan gempa yang populer digunakan. Daktilitas struktur yang tinggi merupakan salah satu keunggulan struktur ini, sehingga mampu menahan deformasi inelastik yang besar. Dalam desain, penggunaan metode desain elastis berupa evaluasi non-linear static (Pushover analysis) maupun evaluasi non-linear analisis (Time History Analysis) masih digunakan sebagai dasar perencanaan meskipun perilaku struktur sebenarnya saat kondisi inelastik tidak dapat digambarkan dengan baik. Metode Performance-Based Plastic Design (PBPD) berkembang untuk melihat perilaku struktur sebenarnya dengan cara menetapkan terlebih dahulu simpangan dan mekanisme leleh struktur sehingga gaya geser dasar yang digunakan adalah sama dengan usaha yang dibutuhkan untuk mendorong struktur hingga tercapai simpangan yang telah direncanakan. Studi dilakukan terhadap struktur baja 5 lantai yang diberi beban gempa berdasarkan SNI 1726, 2012 dan berdasarkan metode PBPD. Hasil analisa menunjukkan bahwa struktur yang diberi gaya gempa berdasarkan metode PBPD mencapai simpangan maksimum sesuai simpangan rencana dan kinerja struktur yang dihasilkan lebih baik .


2012 ◽  
Vol 204-208 ◽  
pp. 1066-1069
Author(s):  
Yan Jun Li ◽  
Ping Liu

Four specially shaped columns with HRB500 reinforcement were tested under low cyclic loading. The hysteretic curve, yield load, ultimate load, displacement ductility and rigidity degradation were compared in order to research the effect of axial compression ratio on ductility and bearing capacity of specially shaped column with HRB500 reinforcement. It is shown that the axial compression ratio has greater influence on ductility and bearing capacity. With the increase of axial compression ratio, the bearing capacity of HRB500 reinforcement concrete specially shaped column can be enhanced while the deformation capacity becomes worse. The hysteretic characteristic of specially shaped columns with HRB500 reinforcement is improved and the stiffness degeneration becomes slow with the decrease of axial compression ratio.


2008 ◽  
Vol 400-402 ◽  
pp. 329-334
Author(s):  
Ze Liang Yao ◽  
Zhen Jian ◽  
Guo Liang Bai

It is difficult and important to accurately calculate single pile ultimate bearing capacity during pile foundation design. Typical computational methods on single pile ultimate bearing capacity are contrastively analyzed in this paper. Contact element method on single pile ultimate bearing capacity is relatively accurate and economical, but it isn’t used in practical projects until now because its computational process is complicated. 343 different single pile ultimate bearing capacities are calculated with the contact element method in order to study a simple computational formula based on the contact element method. All data calculated are analyzed with a linear recursive multi-analysis program which is programmed with Fortran90. A simple computational formula on the contact element method is presented based on the analysis results. The simple computational formula, the experiential formula in the code, the contact element method and the static load experiment method are respectively used to calculate single pile ultimate bearing capacity in two practical projects in order to test the simple computational formula. The results show that the simple computational formula is relatively accurate. Some advice is presented based on the analysis results.


Author(s):  
Prashant Sunagar ◽  
Manish S Dharek ◽  
K Nruthya ◽  
K S Sreekeshava ◽  
B Nagashree ◽  
...  

2014 ◽  
Vol 1065-1069 ◽  
pp. 1203-1207
Author(s):  
Yan Lin ◽  
Xue Jun Zhou ◽  
Yu Chen Liu ◽  
Wen Qing Kong

A new type of concrete-filled square steel tubular column to steel-encased concrete composite beam joint is proposed. In order to study the influences of parameters on bearing capacity for the joint formed plastic hinge in the beam end, nonlinear finite element analysis under monotonic loading is conducted by software ANSYS. The results show that axial compression ratio has little influence on joint bearing capacity, and with the increasing of it, the bearing capacity is enhanced slightly. The height of U-shape steel has a significant impact on joint bearing capacity, and with the rise of it, the bearing capacity is enhanced obviously. The thickness of U-shape steel has a comparatively obvious effect on joint bearing capacity with certain limits, and with the growth of it, the bearing capacity of the joint is also grown observably. The diameter of longitudinal reinforcement in the flange slab of beam has some effects on joint bearing capacity, and with the improvement of diameter, the bearing capacity is achieved.


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