DYNAMIC ANALYSIS OF BRIDGES WITH PLASTIC HINGES UNDER EXTREME EARTHQUAKES

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
T. Y. Lee ◽  
K. J. Chung
Keyword(s):  
Plastic Hinge ◽  
Concrete Columns ◽  
Computational Method ◽  
Past Study ◽  
Plastic Hinges ◽  
Concrete Core ◽  
Cover Concrete ◽  
Deformable Bodies ◽  
Fiber Element ◽  
Isolated Bridge

This study is aimed to develop the model of fiber element in the Vector Form Intrinsic Finite Element (VFIFE) to analyze the plastic hinges of reinforced-concrete columns for bridges subjected to extreme earthquakes. The VFIFE, a new computational method, is adopted in this study because of the superior in managing the engineering problems with material nonlinearity, discontinuity, large deformation and arbitrary rigid body motions of deformable bodies. In the past study, a plastic hinge is idealized as a bilinear elastoplastic model with a fracture moment. In order to analyze the realistic behavior of the plastic hinge, especially in ultimate state, the fiber element is developed to simulate the plastic hinge by using stress-strain relations in cover concrete, core concrete and steel fibers. The developed fiber element is verified to be feasible and accurate through numerical simulation. A three-span-continuous isolated bridge is analyzed to investigate the function of the columns and unseating prevention devices and to predict the collapse situation of the whole bridge. In addition, the analysis results are compared between the fiber element and bilinear elastoplastic element.

CONFINING TRANSVERSE REINFORCEMENTS FOR CIRCULAR COMPOSITE HOLLOW RC COLUMN WITH INNER TUBE

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Deok Hee Won ◽  
Woo-Sun Park ◽  
Ji-Hye Seo ◽  
Nam-Hyung Lim ◽  
Taek Hee Han
Keyword(s):  
Calculation Method ◽  
Rational Design ◽  
Plastic Hinge ◽  
Concrete Core ◽  
Rc Columns ◽  
Displacement Ductility ◽  
Rc Column ◽  
Cover Concrete ◽  
Strength And Stiffness ◽  
Aashto Lrfd

The confining transverse reinforcement has been arranged in plastic hinge region to resist the lateral load, increasing the lateral confining effect in the substructure of the bridge. Columns increased the seismic performance by securing the stiffness and ductility. The calculation method of confining transverse reinforcements is reported in AASHTO-LRFD specification. This specification is only proposed for solid RC columns. In this reason, if this specification is applied to another column as composite column besides solid RC columns, a proper evaluation of the column cannot be done. In particular, composite hollow RC columns have limits for applying this specification. The composite hollow RC column consists of transverse longitudinal reinforcement, cover concrete, core concrete, and an inner tube inserted on hollow face. It increases the ductility, strength, and stiffness of the composite hollow RC column. This paper suggests a modified equation for an economical and rational design through an investigation of displacement ductility when applied to the existing specifications of the composite hollow RC column. Moreover, parametric study is performed for evaluating the detail behavior. Using these results, a calculation method of economic transverse reinforcements is proposed.

scholarly journals QUANTIFYING THE EFFECTS OF EPOXY REPAIR OF REINFORCED CONCRETE PLASTIC HINGES

2020 ◽  
Vol 53 (1) ◽  
pp. 37-51
Author(s):  
Kai J. Marder ◽  
Kenneth J Elwood ◽  
Christopher J. Motter ◽  
G. Charles Clifton
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Plastic Hinge ◽  
Deformation Capacity ◽  
Structural Behaviour ◽  
Plastic Hinges ◽  
Strong Earthquakes ◽  
Beam Elements ◽  
Cover Concrete ◽  
Residual Deformations

Modern reinforced concrete structures are typically designed to form plastic hinges during strong earthquakes. In post-earthquake situations, repair of moderate plastic hinging damage can be undertaken by filling the crack system with epoxy resin and reconstituting spalled cover concrete. This study uses available experimental test data, including three large-scale ductile beams tested by the authors, to investigate the effects of epoxy repair on the structural behaviour of plastic hinges, with a focus on beam elements. Factors that have been neglected in past studies, including the effects of residual deformations at the time of repair, are given special attention. It is found that epoxy-repaired plastic hinges can exhibit different behaviour from identical undamaged components in terms of stiffness, strength, deformation capacity, and axial elongation. Potential explanations for the observed differences in behaviour are given, and recommendations are made for how these differences can be quantified in order to relate the expected response of an epoxy-repaired plastic hinge to the response that would be calculated for an identical undamaged component.

Experiment Study on Cyclic Behavior of Concrete Filled Steel Tube (CFST) Column-Reinforced Concrete (RC) Beam Connections

2009 ◽  
Vol 417-418 ◽  
pp. 833-836 ◽  
Author(s):  
Qing Xiang Wang ◽  
Shi Run Liu
Keyword(s):  
Reinforced Concrete ◽  
Tube Wall ◽  
Plastic Hinge ◽  
Steel Tube ◽  
Reinforced Concrete Beams ◽  
Cyclic Behavior ◽  
Concrete Core ◽  
Concrete Filled Steel Tube ◽  
Steel Bars ◽  
Moment Resisting

The test results of six connections under cyclic loading are presented in the paper. Each test specimen was properly designed to model the interior joint of a moment resisting frame, and was identically comprised of three parts that including the circular concrete filled steel tube columns, the reinforced concrete beams, and the short fabricated connection stubs. Energy dissipation was designed to occur in the beams during a severe earthquake. Steel bars which were embedded into concrete core and welded to the connection stubs, were used to transfer the force distributed by the reinforcing bars of concrete beam to the concrete core. The results indicated that the embedded steel bars were very efficient in eliminating the stress concentration on the tube wall and there was no visible deformation occurred on the tube wall until the collapse of the specimen. Furthermore, the connection of each specimen had enough capacity and thus the plastic hinge appeared in the beams. As results, the ductility of this new type structure directly depended on the RC beams.

Combined Reinforced Concrete Columns Strengthening with Steel Clipping and Concrete Surfacing

2021 ◽  
pp. 11-22
Author(s):  
Ю. Г. Москалькова ◽  
С. В. Данилов ◽  
В. А. Ржевуцкая
Keyword(s):  
Reinforced Concrete ◽  
Load Transfer ◽  
Limit State ◽  
Concrete Columns ◽  
Ultimate Limit State ◽  
Concrete Core ◽  
Reinforced Concrete Columns ◽  
Entire Height ◽  
Complex Structural ◽  
Ultimate Limit

Постановка задачи. Исследуется метод усиления железобетонных колонн устройством стальной обоймы с обетонированием, который позволяет восстанавливать эксплуатационные показатели колонн, имеющих значительные дефекты и повреждения. Предпосылкой настоящих исследований явилось предположение о том, что усиление стальной обоймой с обетонированием является эффективным способом повышения несущей способности железобетонных колонн, причем вариант приложения нагрузки - только на бетонное ядро или ко всему сечению - существенно на эффективность усиления не влияет. В связи с этим целью исследования является определение необходимости устройства стального оголовка и включения в работу ветвей стальной обоймы при условии обетонирования стержня колонны по всей высоте. Результаты и выводы. Рациональным признан способ передачи нагрузки только на бетонное ядро усиленных колонн, поскольку устройство оголовка стальной обоймы требует применения сложных конструктивно-технологических решений, но при этом дополнительно увеличивает несущую способность незначительно (согласно проведенным исследованиям менее чем на 10 %). Ввиду отсутствия необходимости устройства конструкций стального оголовка снижаются трудоемкость и сроки производства работ по усилению колонн. Statement of the problem. The method of strengthening reinforced concrete columns with a steel clipping and the concrete surfacing is investigated. This method allows one to repair the columns with significant defects and damage. The prerequisite for this study was the assumption of strengthening with a steel clipping and the concrete surfacing is an effective way to increase the ultimate limit state of reinforced concrete columns, furthermore, the option of applying the load (only to the concrete core or to the entire section) does not significantly affect the strengthening effectiveness. In this regard, the purpose of the investigation was to identify the need to include the steel jacketing in the work, on the condition the column is coated with concrete along with the entire height. Results and conclusions. The load transfer method only to the concrete core of the strengthened columns is recognized as rational since the device of the steel clipping head requires the use of complex structural and technological solutions, but at the same time additionally increases the ultimate limit state insignificantly (according to the studies by less than 10 %). Due to the absence of the need to establish structures of the steel jacketing head, the labor intensiveness and terms of work production on strengthening the columns are reduced.

Using the Explicit Dynamic Method to Simulate Pile Dynamical Driving Process

2010 ◽  
Vol 163-167 ◽  
pp. 366-371
Author(s):  
Jian Bing Lv ◽  
He Lin Fu ◽  
Hua Zhi Li ◽  
Zhe Liu
Keyword(s):  
Method Development ◽  
Elastic Solid ◽  
Computational Method ◽  
Dynamical Analysis ◽  
Pile Driving ◽  
Past Study ◽  
Analysis Method ◽  
The Past ◽  
Explicit Dynamic ◽  
Dynamical Stress

The dynamic pile driving process is so complex that till now the analysis on the process had been focusing on the filed test or laboratory test. However, the past study about the dynamic process is a time consuming one; with the computational method development, the numerical simulation on this process is possible. In this paper, explicit dynamical analysis method is adopted, the pile is simulated using the elastic solid element, two computational cases are considered and finally the pile driving process dynamical stress is studied.

Investigation of Plastic Hinge Length in Reinforced Concrete Columns on Column Behavior

2017 ◽  
Vol 21 ◽  
pp. 45-49
Author(s):  
Mehmet Kamanli ◽  
Alptug Unal
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Concrete Columns ◽  
Analysis Program ◽  
Reinforced Concrete Buildings ◽  
Reinforced Concrete Columns ◽  
Concrete Buildings ◽  
Horizontal Stability ◽  
Plastic Hinge Length

In reinforced concrete buildings in case of a possible earthquake, the buildings slamp as they lost their horizontal stability because of hinging of column ends. The assumptions for plastic hinge lengths are present during project stage of reinforced concrete buildings. According to Turkish Earthquake Regulations, although plastic hinge length is determined to be 0.5h, it's known that plastic hinge length is determined via various formulas in some other regulations all over the world. In reinforced concrete columns, it's necessary to indicate the effect of plastic hinge length on the column behavior. For this purpose, pushover analysis of 5 column samples having different plastic hinge lengths was performed with non-linear analysis program. As a result of pushover analysis, situations of plastic hinges formed in columns and their load-displacement curves were determined. The graphs and the data were compared and the results were discussed.

The Plastic Hinge

2015 ◽  
pp. 172-230
Keyword(s):  
Reinforced Concrete ◽  
Structural Analysis ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Plastic Hinges

The plastic hinge is a key concept of the theory of frames that differentiates this theory from the remaining models for structural analysis. This chapter is exclusively dedicated to define this concept and describe the different models of plastic hinges. It also discusses the differences of implementation between plastic hinges in steel frames (Sections 6.1-6.4) and those in reinforced concrete structures (Sections 6.5-6.6). This chapter is based on the ideas presented in Chapter 5 and it allows formulating the models for elasto-plastic frames that are introduced in the next chapter.

scholarly journals Inelastic behavior of reinforced concrete cantilever beam with embedded steel truss in flexural plastic hinge under cyclic loading

2019 ◽  
Vol 258 ◽  
pp. 04007
Author(s):  
Fatmawati Amir ◽  
Iman Satyarno ◽  
Djoko Sulistyo
Keyword(s):  
Cyclic Loading ◽  
Shear Failure ◽  
Plastic Hinge ◽  
Hysteretic Behavior ◽  
Inelastic Behavior ◽  
Plastic Hinges ◽  
Laboratory Test Results ◽  
Steel Truss ◽  
Shear Failures ◽  
Ductile Behavior

Structures are expected to have ductile behavior under major earthquakes. One requirement to achieve this ductile behavior is when the structures have no shear failures in their elements. This paper discusses a new method by using the embedded steel truss in the flexural plastic hinges of beam to avoid shear failure. As already known that the shear strength provided by the concrete will be decreased when the ductility of flexural plastic hinges develop in a member. Therefore, a conservative procedure by ignoring the role of concrete in flexural plastic hinges in resisting the shear demand is adopted by some codes. This will increase the demand for shear reinforcement provided by the stirrup or transverse reinforcement in the plastic hinge; yet it still does not ensure that the shear failure does not come to happen. From the laboratory test results under cyclic loading in this study, it can be noted that the beam with embedded steel truss in the plastic hinge has better hysteretic behavior than the one without the embedded steel truss. The evaluation of test result is also shown the strength of the beam with the embedded steel truss in the plastic hinge is not reduced with an increase in the amplitude of the drift of 1.4 to 3.5. Besides, the strength of the beam without embedded steel truss in the plastic hinge is reduced with an increase in the amplitude of the drift after reaching 2.5.

Evaluation of Formation of Plastic Hinge and Seismic Behavior of Steel Structures Due to Soil–Structure–Tunnel Interaction

2020 ◽  
Vol 14 (03) ◽  
pp. 2050014
Author(s):  
Arash Rostami ◽  
Abdolreza S. Moghadam ◽  
Mahmood Hosseini ◽  
Nima Asghari
Keyword(s):  
Seismic Response ◽  
Land Surface ◽  
Plastic Hinge ◽  
Free Field ◽  
Steel Structures ◽  
Underground Structures ◽  
Effective Parameters ◽  
Plastic Hinges ◽  
Underground Cavities ◽  
Real Earthquake

The seismic design of the structures is carried out by technical regulations and codes in free-field conditions (regardless of underground cavities). With the availability of tunnels and the complex interaction between the tunnel and the aboveground structures, which may be contemplated wrongly, it could be dangerous for over ground buildings and structures. Consequently, the examination of the underground tunnels and their impact on the land surface and adjacent buildings seismic response seems to be significant. The present research focuses on formation of the plastic hinges in steel structures due to underground cavities and the soil–tunnel–structure interaction of underground structures. First, an existing model was verified by finite element method and the results were compared with a sample specimen. Thus, several effective parameters were considered and studied such as soil type, multi-story structures (4, 8 and 12 stories) and dynamic load type. Then the models were evaluated under real earthquake records. As a result, the seismic response of the structures and plastic conditions of plastic hinge conditions were obtained. The results indicate that the underground cavities have affected the formation of plastic hinges in the structure. They increased the input energy to the structure and had an impact on the total behavior of the structures. Also, the high-rise structures were much more vulnerable to underground tunnels. Therefore, the structures which are located above the underground cavities should be retrofitted and rehabilitated.

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