scholarly journals NUMERICAL INVESTIGATION ON CYCLIC BEHAVIOR OF RING-BEAM CONNECTION TO GANGUE CONCRETE FILLED STEEL TUBULAR COLUMNS

As a promising composite structure, gangue concrete filled steel tubular (GCFST) column exhibites favarable characteristics including high strength and economic efficiency. This paper conducted numerical investiagations on structural behavior of a ring-beam connection to GCFST column with concrete beam under cyclic loading. Furthermore, finite element models of column-beam connections were developed using ABAQUS and validated against full-scale experimental tests to identify accuracy of selected modeling approaches. Using these validated models, stress distribution of each component was examined to study the force-transferring mechanism among the components and failure modes of the ring-beam connection. Research study indicated that the ring-beam connection showed a reasonable force-transferring mechanism under cyclic loading and the remarkable earthquake-resistant performance with high capacity and acceptable ductility. Finally, parametric studies were performed to assess the influences of beam-to-column stiffness ratio,steel ratio, axial load level, and concrete compressive strength on connection cyclic behaviors. Parametric studies provided some suggestions and references for the application of the ring-beam connection in various engineering projects.

2015 ◽  
Vol 15 (01) ◽  
pp. 1450033 ◽  
Author(s):  
Qian-Yi Song ◽  
Amin Heidarpour ◽  
Xiao-Ling Zhao ◽  
Lin-Hai Han

Earthquake causes wide and severe damage to building structures, due to not just the great ground motion but also secondary actions, such as impact, blast or fire, occurring after earthquake. The extreme combined loading scenario should be considered for safety of buildings and lives. Taking fire for example, the combined load can be considered as an event in which the structures are first partially damaged under an earthquake and then attacked by fire. In order to investigate the post-earthquake loading scenario, it is important to assess the partial damage caused by earthquake on different components of structures. The behavior of welded steel I-beam to hollow square tubular columns is investigated herein. A detailed experimental study is presented in which two groups of unstiffened welded steel connections, with the same configurations, subjected to static and cyclic loading are considered. The flexibility and strength of the connections are measured, while the damage phenomena and failure modes are explored during the tests. The connection damage is found to be a cumulative fracture developing process which leads to significant gradual degradation of the mechanical properties of the connection. The quantificational evaluations of the cyclic loading induced damage are also carried out to investigate the connection damage level according to different loading intensities. A finite element modeling numerical study is also carried out to validate the experimental results and a good agreement is achieved. The test results and FE modeling provide a benchmark data for the unstiffened welded connections and can be used for further investigations of the connections subjected to combined actions such as post-earthquake fire.


2011 ◽  
Vol 71-78 ◽  
pp. 3474-3479
Author(s):  
Qian Zhu ◽  
Jun Hai Zhao ◽  
Xue Ying Wei ◽  
Juan Wang ◽  
Su Wang

Recycling of waste concrete is beneficial and necessary from the viewpoint of environmental preservation and effective utilization of resources. The carbon fiber reinforced polymer tendon (CFRP tendon) has been widely used in concrete structures due to its high-strength, lightweight, good erosion-resistance, diamagnetism and anti-fatigue. The compressive behavior of recycled-concrete-segment/lump filled steel tubular columns with inner CFRP tendons are investigated in this paper. The formula of ultimate capacities of the columns under axial compression has been derived based on unified strength theory. Good agreement can be found from the comparison of the analytical results obtained in this paper and experimental data. Parametric studies are carried out to evaluate the effects of intermediate principal stress, mixture ratio of the recycled concrete and reinforcement ratio on the bearing capacities of the columns.


Author(s):  
Andrés Lapuebla-Ferri ◽  
Cesar Lacuesta ◽  
Manuel L. Romero ◽  
José M. Adam

In this work, a non-linear 3D numerical model to study concrete-filled tubular (CFST) columns is presented. The numerical model is capable to consider the passive confinement that occurs in the concrete core of CFST columns, under which an increase in the strength and ductility of the element is expected. Passive confinement is governed by the volumetric deformation of the concrete core and by the increment of concrete strength, so it was necessary to define both aspects in the constitutive model. In the volumetric deformation, the elastic and plastic components were included, the latter by using the Drucker-Prager model. Different values for the angle of dilatancy were defined for normal and high strength concrete. The model was validated by using experimental tests performed on stub columns and eccentrically loaded columns. In addition, different section geometries were tested. According to the results, the model was able to describe the non-uniform confinement that appears in the concrete core of CFST columns. 


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chayanon Hansapinyo ◽  
Chinnapat Buachart ◽  
Preeda Chaimahawan

This paper presents an experimental study on the cyclic behavior of fifteen concrete-filled steel tubular columns subjected to vertical cyclic loading. All test samples’ cross-sectional area is 75 × 75 mm2square, and they are 500 mm long. The main variables in the test are the thickness of the steel tube (1.8 and 3.0 mm with the width-to-thickness ratios (b/t) of 41.7 and 25), the strength of the infilled concrete (no-fill, 23 MPa, and 42 MPa), and the inclined angle (0, 4, and 9 degrees). The results show that all samples failed due to local buckling in compression followed by tearing of the steel tube in tension. The inclination angles of 4 and 9 degrees decreased the vertical compressive capacity of the 1.8 mm vertical hollowed steel column by 34 and 39 percent, respectively. However, the infilled concrete and thicker tube (3.0 mm) could substantially reduce the adverse effect of the inclination angle. The compressive ductility of the hollowed column with the thinner tube was significantly enhanced by the infilled concrete as well.


Author(s):  
Jiantao Wang ◽  
Qing Sun

Under violent earthquake motions, the severe damage in critical regions of structures could be ascribed to cumulative damage caused by cyclic loading. Using the high strength (HS) materials in concrete-filled steel tubular (CFST) columns is the effective way and popular tendency to promote the seismic behavior in anti-seismic design. In this paper, an experimental study on the hysteretic performance of high strength circular concrete-filled thin-walled steel tubular columns (HCFTST) columns was carried out. A total of six specimens were tested under constant axial compression combining cyclic lateral loading. The tested parameters were the different combinations of diameter-to-thickness (D/t) ratio, axial compression ratio (n) and concrete cylinder compressive strength (fc).The failure modes, load-displacement hysteretic curves, skeleton curves, dissipated energy and stiffness degradation were examined in detail. Through the experiment analysis result, it indicates that the ultimate limit state is reached as the severe local buckling and rupture of the steel tubes accompanying the core concrete crushing occur. Using high strength materials could have a larger elastic deformation capacity and the higher axial compression ratio within test scopes could motivate the potential of HS materials. In brief, the HCFTST columns with ultra-large D/t ratios under reasonable design could perform excellent hysteretic performance, which can be applied in earthquake-prone regions widely.


2007 ◽  
Vol 353-358 ◽  
pp. 2081-2084
Author(s):  
Cheol Min Yang ◽  
Young Moon Kim ◽  
Nag Ho Ko ◽  
Dong Pyo Hong

This paper proposes a new semi-rigid detail used high-strength bolts for use in earthquake resistant structures. These specimens were single-side beam-to-column assemblies that are representative of exterior beam-to-column connections, and they were composed of identical beam and column but had the different connection details, respectively. All beam-to-column assembly required no welding. Specimen 1 (TSD) was standard Top-Seat-Double-web-angle but specimen 2 (MTSD) was made by modified shape. Two high-strength bolted steel semi-rigid connections were prepared and cyclic load was applied to each test specimen using displacement control. The cyclic load and displacements, moment-rotation plots, and the deformation pattern or failure modes for all the test cases are presented. The strength, stiffness, energy, and ductility of the tested connections are compared to each other.


2008 ◽  
Vol 400-402 ◽  
pp. 693-699
Author(s):  
J.F. Wang ◽  
Lin Hai Han

This paper discussed the results of experiments on bolted moment connection joints of square or circular concrete filled steel tubular (CFST) columns and H-shaped steel beam using high-strength blind bolts under cyclic loading. The objective of this work was to study the seismic performance of the blind bolted flush endplate connections to CFST columns. The test parameters varied were the column section type and the thickness of the endplate. The feasibility of the proposed beam-column connection is successfully verified by the experiments. The test results showed that under cyclic loading the tested specimens displayed large rotation ductility capacities and could satisfy the request of the structural seismic design. When subjected to cyclic loading, most of failure modes of the tested joints are similar to those under monotonic loading. Moreover, the energy dissipation of the type joints is influenced by the column section type and the thickness of the endplate.


Author(s):  
George Z. Voyiadjis ◽  
S. H. Hoseini ◽  
G. H. Farrahi

Recent experiments on metals have shown that all of the stress invariants should be involved in the constitutive description of the material in plasticity. In this paper, a plasticity model for metals is defined for isotropic materials, which is a function of the first stress invariant in addition to the second and the third invariants of the deviatoric stress tensor. For this purpose, the Drucker–Prager yield criterion is extended by addition of a new term containing the second and the third deviatoric stress invariants. Furthermore for estimating the cyclic behavior, new terms are incorporated into the Chaboche's hardening evolution equation. These modifications are applied by adding new terms that include the effect of pervious plastic history of deformation on the current hardening evaluation equation. Also modified is the isotropic hardening rule with incorporating the effect of the first stress invariant. For calibration and evaluation of this plasticity model, a series of experimental tests are conducted on high strength steel, DIN 1.6959. In addition, finite element simulations are carried out including integration of the constitutive equations using the modified return mapping algorithm. The modeling results are in good agreement with experiments.


ce/papers ◽  
2017 ◽  
Vol 1 (2-3) ◽  
pp. 3661-3670
Author(s):  
Fatemeh Javidan ◽  
Amin Heidarpour ◽  
Xiao-Ling Zhao ◽  
Riadh Al-Mahaidi

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