scholarly journals RESTORING FORCE CHARACTERISTIC MODEL OF CONCRETE-FILLED SQUARE STEEL TUBE BEAM-COLUMNS

2019 ◽  
Vol 84 (765) ◽  
pp. 1485-1495
Author(s):  
Toshiyuki FUKUMOTO
Keyword(s):  
Steel Tube ◽  
Force Characteristic ◽  
Restoring Force ◽  
Characteristic Model ◽  
Beam Columns ◽  
Square Steel Tube

EVALUATION METHOD FOR ALLOWABLE SHORT-TERM FLEXURAL STRENGTH AND YIELD STRENGTH OF CONCRETE-FILLED STEEL TUBULAR BEAM-COLUMNS

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Takashi Fujinaga ◽  
Tomoya Kawabata
Keyword(s):  
Flexural Strength ◽  
Yield Strength ◽  
Evaluation Method ◽  
Steel Tube ◽  
Superposition Method ◽  
Short Term ◽  
Restoring Force ◽  
Beam Columns ◽  
Slope Factor ◽  
The Moment

According to the Recommendations for Design and Construction of Concrete Filled Steel Tubular Structures from Architectural Institute of Japan, the allowable short-term flexural strength (ASFS) can be used as the yield strength for the restoring force characteristics model of concrete-filled steel tube (CFST) members. Therefore, it is necessary to examine whether the ASFS can be appropriate as an alternative for the yield strength. Furthermore, as the ASFS is typically calculated using the superposition method, the value of the deformation at the superposed strength cannot be evaluated. To address these issues, in this study, numerical analysis was conducted on the moment-curvature relation of CFST column sections using the finite fiber method. The characteristics of the point of ASFS and evaluation method for flexural yield strength in a broad sense were examined using the slope factor and strength satisfaction factor methods. The corresponding slope factor is larger than the value (1/3) that is generally used for the yield strength definition. Therefore, using the ASFS is as the yield strength of the CFST section is reasonable. Additionally, the formula for the curvature at the ASFS was also proposed.

EFFECT OF STRAIN-STRESS RELATIONSHIP OF STEEL TUBE ON THE INITIAL STIFFNESS OF SQUARE CFT COLUMNS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Ryo Handa ◽  
Masae Kido ◽  
Mao Liu ◽  
Keigo Tsuda
Keyword(s):  
Yield Strength ◽  
Cross Section ◽  
Bending Moment ◽  
Steel Tube ◽  
Force Characteristic ◽  
Initial Stiffness ◽  
Short Term ◽  
Restoring Force ◽  
Strain Stress ◽  
Cft Column

The restoring force characteristic of a concrete filled steel tubular (CFT) column is modeled with three straight lines which show the relation of M-R. The initial stiffness is calculated by assuming that the steel and concrete portions are fully effective and materials are elastic. The first break point is the yield bending moment of the CFT column. The yield bending moment is defined by the bending moment when a part of the cross-section yield or the allowable strength for short-term loading obtained by the superposed strength method. It is supposed that the theoretical initial stiffness obtained by assuming that the whole cross section is effective is different from the real one. This study aims to clarify effects of strain-stress relation on the yield strength and allowable strength for short-term loading and the initial stiffness. Three types of stress-strain relations for steel are used, elastic-perfectly plastic model, Menegotto-Pinto's model and Morino's model. According to the analytical results, the difference between allowable strength and yield strength becomes larger as the axial load ratio, indexes Rh and k which are used in Menegotto-Pinto's model and Morino's model increase.

Flexural Capacity Study on Square Tube Filled with Steel Reinforced Concrete Members

2010 ◽  
Vol 163-167 ◽  
pp. 1574-1577 ◽  
Author(s):  
Tong Feng Zhao ◽  
Hong Nan Li ◽  
Jia Huan Yu
Keyword(s):  
Reinforced Concrete ◽  
Steel Tube ◽  
Flexural Capacity ◽  
Steel Reinforced Concrete ◽  
Deformation Curves ◽  
Concrete Members ◽  
Bending Load ◽  
Square Steel Tube ◽  
Abaqus Software

Moment-deformation curves of square steel tube filled with steel reinforced concrete subjected to bending load were simulated by the ABAQUS software. Calculated and experimental curves agreed well with each other. Through studying further the calculated member, the behavior of materials subjected to moment is given. Finally, flexural capacity formula of square steel tube filled with cross steel reinforced concrete is proposed.

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