Experimental Study on the Influence of Boundary Condition on the Behavioral Characteristics of CFT Square Columns under Constant Axial Load upon a Fire

2011 ◽  
Vol 82 ◽  
pp. 521-526 ◽  
Author(s):  
Heung Youl Kim ◽  
Kyung Hoon Park ◽  
Ki Hyuk Kwon
Keyword(s):  
Boundary Condition ◽  
Cross Section ◽  
Fire Resistance ◽  
Axial Load ◽  
Load Ratio ◽  
Steel Tube ◽  
Section Size ◽  
Cft Column ◽  
Major Factors ◽  
Resistance Performance

The temperature of the steel tube of a CFT column rises rapidly upon a fire causing the deterioration of its strength, while the concrete inside of the tube having large heat capacity provides fire-resistance performance. In order to employ CFT columns as fire-resistant structure, it is necessary to conduct studies on the factors exerting influence on structural capacities and the influence associated with each condition. Concrete’s compressive strength, cross-section size, axial load ratio and boundary condition are the major factors which are influential in fire-resistance performance. In particular, boundary condition between columns and beams is one of the major factors which decide fire-resistance performance because it exerts influence on load carrying capacity. The result of the test conducted in this study showed that fire-resistance time of 106 minutes was secured in the specimens with clamped ends and that of 89 minutes in those with pinned ends when cross-section size was 360mm by 360mm. In the specimens with cross-section size of 280 mm × 280mm, fire-resistance time of 113 minutes was secured under the condition of clamped ends and that of 78 minutes was secured under the condition of pinned ends.

An Experimental Study on the Fire Behavior of CFT Columns under the Constant Axial Loading Condition in Fire

2012 ◽  
Vol 446-449 ◽  
pp. 1298-1306
Author(s):  
Hyung Jun Kim ◽  
Heung Youl Kim ◽  
In Hwan Yeo
Keyword(s):  
Boundary Condition ◽  
Fire Resistance ◽  
Fire Behavior ◽  
Load Ratio ◽  
Steel Tube ◽  
Cross Sectional ◽  
Cross Sectional Size ◽  
Major Factors ◽  
In Fire ◽  
Resistance Performance

The temperature of the steel tube of a CFT column rises rapidly upon a fire causing the deterioration of its strength, while the concrete inside of the tube having large heat capacity provides fire-resistance performance. In order to employ CFT columns as fire-resistant structure, it is necessary to conduct studies on the factors exerting influence on structural capacities and the influence associated with each condition. Concrete’s compressive strength, cross-sectional size, axial load ratio and boundary condition are the major factors which are influential in fire-resistance performance. In particular, boundary condition between columns and beams is one of the major factors which decide fire-resistance performance because it exerts influence on load carrying capacity. The result of the test conducted in this study showed that fire-resistance time of 106 minutes was secured in the specimens with clamped ends and that of 89 minutes in those with pinned ends when cross-sectional size was 360 by 360. In the specimens with cross-sectional size of 280 x 280, fire-resistance time of 113 minutes was secured under the condition of clamped ends and that of 78 minutes was secured under the condition of pinned ends.

Fire Resistance Evaluation of Reinforced Concrete Columns Using Axial Load Ratio and Slenderness Ratio

2014 ◽  
Vol 905 ◽  
pp. 268-272
Author(s):  
In Hwan Yeo ◽  
Bum Yean Cho ◽  
Jae Hong An ◽  
Byung Youl Min
Keyword(s):  
Fire Resistance ◽  
Axial Load ◽  
Slenderness Ratio ◽  
Load Ratio ◽  
Cost Effective ◽  
Concrete Columns ◽  
Accurate Estimation ◽  
Structural Members ◽  
Standard Fire ◽  
Resistance Performance

Since the column members in buildings deal with both vertical and horizontal loads, appropriated amount of load should be estimated in order to evaluate the fire resistance performance of the columns under loaded condition. However, according to the ISO 834, the international standard for the evaluation of structural members, the fire resistance performance evaluation of column members is only based on the displacement and displacement rate under loaded condition in a standard fire. The purpose of this study is to suggest appropriate axial load ratios for the evaluation of fire resistance performance. The test conducted in this study produced appropriate axial load ratios for different slenderness ratios. They are expected to contribute to more accurate estimation of fire resistance performance and more efficient and cost-effective structural design.

Fire Resistance of Reinforced Concrete Columns with Square Cross Section

2007 ◽  
Vol 10 (4) ◽  
pp. 353-369 ◽  
Author(s):  
Bo Wu ◽  
Zhou Hong ◽  
Gui-He Tang ◽  
Chao Wang
Keyword(s):  
Cross Section ◽  
Fire Resistance ◽  
Axial Load ◽  
Load Ratio ◽  
Concrete Columns ◽  
Eccentricity Ratio ◽  
Explosive Spalling ◽  
Strength Concrete ◽  
Axial Load Ratio ◽  
Simulation Results

Calculation of the fire resistance of 480 square cross section normal strength concrete (NSC) columns and 480 high strength concrete (HSC) columns, made with siliceous aggregate, is presented in this paper. The variables considered in the study include concrete strength (NSC and HSC), dimension of column cross section, axial load ratio, load eccentricity ratio (i.e., ratio of load eccentricity to dimension of column cross section), and steel ratio (i.e., ratio of longitudinal reinforcement to cross-sectional area of column). Explosive spalling of HSC exposed to fire is also considered approximately. Simulation results show that: (1) increasing the dimension of column cross section, reducing the axial load ratio, and reducing the load eccentricity ratio are all effective measures for improving the fire resistance of both NSC and HSC columns subjected to concentric axial load or eccentric axial load; (2) increasing the steel ratio has no significant influence on the fire resistance of concentrically loaded NSC and HSC columns, but has some positive effect on the fire resistance of eccentrically loaded NSC and HSC columns; (3) explosive spalling of HSC has a significant detrimental influence on the fire resistance of HSC columns. Based on simulation results, a simplified formula is empirically developed to enable determination of the fire resistance of both NSC and HSC columns, and is shown to be applicable to concrete columns with square cross section.

Fire Resistance Performance of Welded Built-up Square CFT Columns with Reduced Intumescent Paint

2015 ◽  
Vol 6 (2) ◽  
pp. 103-112
Author(s):  
SunHee Kim ◽  
KyongSoo Yom ◽  
SungMo Choi
Keyword(s):  
Stress Concentration ◽  
Fire Resistance ◽  
Axial Load ◽  
Load Ratio ◽  
Functional Design ◽  
Steel Tubes ◽  
Composite Effect ◽  
Axial Load Ratio ◽  
The Law ◽  
Resistance Performance

Welded built-up square CFT columns are widely employed in construction field thanks to their structural efficiencies by avoiding stress concentration area and improving workability in fabrication and maximizing the composite effect enabled by bent ribs. Although welded built-up square CFT columns have structural advantages over other members and are widely used, they are classified as non-fireproof in Korea because the steel tubes are directly exposed to a fire. Thus, fire coating required for the columns by the law results in inefficient design. This study suggests welded built-up square CFT columns with reduced coating to enable improved fire-resistance performance for 2˜3 hours. The purpose of the study is to analyse their fire-resistance performance using the variable of axial Load ratio which is the major factor in the performance and suggest efficient functional design with reduced coating.

Comparison Study of Structural Stabilities for H-Section Columns Built with Ordinary Grade Strength Structural Steels According to Boundary Conditions and Lengths at High Temperature

2014 ◽  
Vol 937 ◽  
pp. 424-427
Author(s):  
In Kyu Kwon
Keyword(s):  
Boundary Condition ◽  
High Temperature ◽  
Boundary Conditions ◽  
Fire Resistance ◽  
Structural Steels ◽  
Structural Members ◽  
Steel Buildings ◽  
Standard Fire ◽  
Fire Curve ◽  
Resistance Performance

Fire resistance performance of structural members has been evaluated from each singular section and standard fire curve since the beginning of fire tests. However, the need of the exact fire resistance of H-section columns applied in the steel buildings has increased. The main reason for this is there is a difference between the conditions being conducted during the fire test and that from real situation. In this paper, the structural stability of H-section column made of an ordinary strength grade structural steels, SS 400, SM 400, and SM 490 at high temperature were evaluated and compared with boundary conditions and column’s length. This was done in order to suggest a new guideline for the application of fire protective materials in steel column in which the boundary conditions and column lengths are different from that tested with hinge to hinge and 3500 mm. The findings from this study showed hinge to hinge boundary condition was more conservative. And fire resistance performance of longer columns in the case of hinge to fixed and fixed to fixed boundary condition than from 3500 mm and hinge to hinge boundary condition can sustain at high temperature without adding fire protective materials.

Nonlinear Full-Range Analysis of Steel Reinforced Concrete L-Shaped Columns

2011 ◽  
Vol 243-249 ◽  
pp. 149-155 ◽  
Author(s):  
Zhe Li ◽  
Shao Ji Chen ◽  
Ye Ni Wang ◽  
Cui Ping Zhang ◽  
Jing Xu
Keyword(s):  
Reinforced Concrete ◽  
Axial Load ◽  
Concrete Strength ◽  
Full Range ◽  
Load Ratio ◽  
Neutral Axis ◽  
Steel Reinforced Concrete ◽  
Axial Load Ratio ◽  
Section Size ◽  
Load Angle

The neutral axis change along with axial load ratio, load angle, section size etc. For the neutral axis of SRCLSC(steel reinforced concrete L-shaped column) is neither plumb with the plane that the moment work on, nor parallel with borderlines of SRCLSC section, it is difficult to get loading capacity and ductility of SRCLSC on biaxial eccentric loading. Based on the plane-section assumption, a method for the nonlinear analysis of complete response process for ductility of 15 SRCLSC..It include 36 sets for load angle, 6 sets for axial load ratio, 3 sets for concrete strength, 3 sets for the content of steel, 2 sets for steel style, 3 sets for stirrup ratio, 3 sets for steel location, 3 sets for section size, 3 sets for stirrup diameter about SRCLSC. The ductile behavior of L-shaped, with calculating 1068 loading conditions,are investigated. It concluded that axial load ratio, load angle, and ratio of the spacing of stirrups and longitudinal reinforcement’s diameter (s/d) are most important factors.

Study on Estimate of Load Ratio of Doubly Reinforced Concrete Beam Exposed to the Standard Fire

2017 ◽  
Vol 737 ◽  
pp. 465-470
Author(s):  
Jae Hong An ◽  
In Hwan Yeo ◽  
Ki Soo Jeon ◽  
Ki Ho In
Keyword(s):  
South Korea ◽  
Fire Resistance ◽  
Concrete Beam ◽  
Load Ratio ◽  
Reinforced Concrete Beam ◽  
High Rise ◽  
Standard Fire ◽  
Loading Ratio ◽  
Resistance Performance ◽  
Reinforcement Beam

There are a lot of concerns on safety structure performance by being buildings to be large and high-rise. In particular, damage due to the fire recently leads to a large disaster and therefore a variety of countries operate the regulation on the fire resistance performance depending on the building structure. There are differences on the fire resistance design in each country but 50% of the design load is suggested to be reasonable for the normal temperature during the fire by applying the concept of the loading ratio to the fire resistance design of structures. Since the loading ratio is the factor having a major impact on the evaluation of the fire resistance performance, it should be preferentially considered. The study on setting up the loading ratio to evaluate the fire resistance performance and safety of structures has yet to be fully furnished in South Korea. Therefore, in this paper, the loading ratio proper for the construction status in South Korea is to be taken into account and then the ratio is to be proposed on the single reinforcement beam.

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