Structure behavior of concrete filled double-steel-plate composite walls under fire

2019 ◽  
Vol 22 (8) ◽  
pp. 1895-1908
Author(s):  
Fangfang Wei ◽  
Zejun Zheng ◽  
Jun Yu ◽  
Yongquan Wang
Keyword(s):  
Axial Compression ◽  
Compression Ratio ◽  
Axial Load ◽  
Failure Modes ◽  
Steel Plate ◽  
Local Buckling ◽  
Engineering Practice ◽  
Axial Compression Ratio ◽  
Fire Endurance ◽  
Composite Walls

Concrete filled double-steel-plate composite walls with shear studs, one type of steel–concrete–steel walls, are recently developed and have been used in high-rise buildings, for which fire safety is a big concern. In order to investigate the fire endurance of this new type of concrete filled double-steel-plate composite walls, three specimens with different axial compression ratios and different lengths and intervals of shear studs were tested under one-side ISO-834 standard fire to obtain the temperature distribution, deformation, and detailed failure modes. Each specimen consisted of a concrete filled double-steel-plate composite wall-body and two boundary columns. Moreover, finite-element-based numerical investigations were conducted to confirm and extend experimental findings. All the concrete filled double-steel-plate composite walls failed in compression–flexure mode with the local buckling at the compressive steel plate. The results indicate that the fire endurance of concrete filled double-steel-plate composite walls is significantly affected by the axial compression ratio, the eccentricity of the axial load, and the bond strength between shear studs and concrete. Axial compression ratio, defined as the ratio of axial compression to the nominal compressive capacity of concrete filled double-steel-plate composite walls, has both positive and negative effects on the fire endurance of concrete filled double-steel-plate composite walls. The axial load eccentricity toward the unexposed side is much more detrimental to the fire endurance of concrete filled double-steel-plate composite walls than the one toward the exposed side. In engineering practice, it is recommended that proper intervals (not greater than 300 mm) and lengths (not less than 40 mm) of the shear studs should be used to ensure the bond between concrete and steel plates.

scholarly journals Test on Hysteretic Behaviour of Prestressed Composite Joints with Concrete-Encased CFST Columns

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Kun Wang ◽  
Huihui Luo
Keyword(s):  
Energy Dissipation ◽  
Axial Compression ◽  
Compression Ratio ◽  
Failure Modes ◽  
Shear Failure ◽  
Hysteretic Behaviour ◽  
Axial Compression Ratio ◽  
Flexural Failure ◽  
Composite Joint ◽  
Cfst Columns

Four composite joint specimens consisted of concrete-encased steel beams and concrete-encased concrete-filled steel tube (CFST) columns were tested under lateral cyclic loading, in which three specimens were prestressed and the other was not. In the tests, crack distributions and failure modes of the joint specimens were acquired, and the energy dissipation, rigidity degeneration, ductility, and residential deformation were investigated. Meanwhile, the strain variation of longitudinal rebars and I-steel flanges at beam ends as well as steel tubes in panel zones were analysed. The experimental results showed that a type of mixed mode consisting of shear failure in the panel zone and flexural failure at beam ends was found for three prestressed joint specimens, whilst only flexural failure at beam ends was observed for the non-prestressed one, and all joint specimens showed good hysteretic behaviour. In addition, as can be seen from the skeleton curves, the lateral peak loads of prestressed joint specimens could be enhanced to some extent by increasing the prestressing level, and the axial compression ratio had little effect on lateral loads; meanwhile, the ductility and energy dissipation for prestressed joint specimens also could be reduced by increasing the prestressing level and axial compression ratio.

scholarly journals Experimental Study and Damage Model on the Seismic Behavior of Reinforced Concrete L-Shaped Columns under Combined Torsion

2020 ◽  
Vol 10 (19) ◽  
pp. 7008
Author(s):  
Deyi Xu ◽  
Yang Yang ◽  
Zongping Chen
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Failure Modes ◽  
Shear Failure ◽  
Plastic Hinge ◽  
Combined Loading ◽  
Equivalent Viscous Damping ◽  
Axial Compression Ratio

Due to the advantage of saving indoor space, a special-shaped column frame attracted more attention of the engineers and researchers. This paper presented a quasi-static cyclic loading experiment of six specimens of reinforced concrete (RC) L-shaped columns under compression-flexure-shear-torsion combined loadings to investigate the effect in the ratio of torsion to moment (T/M) and axial compression ratio (n) on their seismic performance. The results showed that the failure modes of L-shaped specimens included bending failure, bending-torsion failure, and torsion-shear failure with the hysteretic curves exhibiting S shape. With the increase of T/M ratio, cracks on the flange developed more fully, and the height of plastic hinge decreased and torsion bearing capacity improved. Besides, as the T/M ratio increased the twist ductility increased, while displacement ductility decreased. On the other hand, with a higher axial compression ratio, torsion bearing capacity and bending stiffness were both increased. Moreover, the equivalent viscous damping coefficient of bending and torsion were 0.08~0.28 and 0.13~0.23, respectively. The average inter-story drift ratio met the requirements of the Chinese standard. Finally, two modified models were proposed to predict the progression of damage for the L-shaped column under combined loading including torsion.

scholarly journals Nonlinear Analysis of Edge Joint on T-shaped Concrete-filled Steel Tubular Column-H-shaped Steel Beam Seismic Performance based on ABAQUS

2019 ◽  
pp. 1-7
Author(s):  
Yadong Bian ◽  
Yichuan Tian ◽  
Yi Zhao ◽  
Long Cheng ◽  
Cheng Hong ◽  
...  
Keyword(s):  
Axial Compression ◽  
Seismic Performance ◽  
Compression Ratio ◽  
Failure Modes ◽  
Ultimate Load ◽  
Steel Beam ◽  
Side Plate ◽  
Obvious Effect ◽  
Finite Element Software ◽  
Axial Compression Ratio

To comprehensively analyze the seismic performance and failure modes of edge joint, which is composed of T-shaped concrete-filled steel tubular column and H-shaped steel beam, the joint was imposed through low frequency cycling loading. Model of edge joint was established by the nonlinear finite element software ABAQUS. The effect of different parameters, such as axial compression ratio and side plate extension length, on the seismic performance were simulated. The results indicates that the buckling of the steel beam occurs at the lateral extension of the side plate due to the strengthening of the side plate; the axial compression ratio has no obvious effect on the ultimate load; the increase of the side plate length can effectively improve the ultimate load.

scholarly journals Hysteretic performance research on high strength circular concrete-filled thin-walled steel tubular columns

2018 ◽  
Author(s):  
Jiantao Wang ◽  
Qing Sun
Keyword(s):  
Axial Compression ◽  
Compression Ratio ◽  
Failure Modes ◽  
High Strength ◽  
Dissipated Energy ◽  
Ultimate Limit State ◽  
Tubular Columns ◽  
Axial Compression Ratio ◽  
Hysteretic Performance ◽  
Thin Walled

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.

Seismic Performance and Confinement Reinforcement Design of High-Strength Concrete Columns Confined with High-Strength Stirrups

2021 ◽  
pp. 136943322199249
Author(s):  
Kun Yang ◽  
Qing-xuan Shi ◽  
Qi Lin
Keyword(s):  
Hysteresis Loop ◽  
Axial Compression ◽  
Compression Ratio ◽  
High Strength Concrete ◽  
Failure Modes ◽  
Failure Process ◽  
High Strength ◽  
Effective Measure ◽  
Strength Concrete ◽  
Axial Compression Ratio

This paper aims at analyzing the failure process, failure modes, characteristics of hysteresis loop and the ductility of 10 high-strength concrete (HSC) columns confined by high-strength complex stirrups under cyclic lateral force and a higher constant axial loading. It is indicated that the hysteresis loop of this type of columns still show plump spindle-shaped at higher axial compression ratio, which shows better ductility, energy dissipation and anti-collapse performance. Therefore, it is an effective measure of setting high-strength stirrups to ensure the good ductility of HSC columns under high axial compression ratio and to increase the limit value of axial compression ratio. The stress of transverse reinforcement is evaluated, which shows that high-strength stirrups have yielded when most of the specimens are destroyed, and the strength of stirrups can be fully developed to provide a better effect of restraint. Based on a large number of experimental data, the relationships between the limit drift, the ductility coefficient of HSC columns and axial compression ratio, stirrup characteristic values, covering layer as well as longitudinal reinforcement ratio are established; the calculation formula of minimum stirrups characteristic value of HSC columns at different seismic levels considering of axial compression ratio is presented.

scholarly journals Seismic Behavior and Finite Element Analysis of Reinforced Concrete Short Columns Impacted by Oblique Earthquakes

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Chunyang Liu ◽  
Guixin Yu ◽  
Xisen Fan ◽  
Changqun Guo ◽  
Fei Li
Keyword(s):  
Axial Compression ◽  
Compression Ratio ◽  
Seismic Behavior ◽  
Shear Failure ◽  
Steel Plate ◽  
High Strength ◽  
Deformation Capacity ◽  
Axial Compression Ratio ◽  
Short Columns ◽  
Small Spacing

This study evaluates the seismic behavior of reinforced concrete (RC) short columns with a high axial compression ratio under oblique earthquake conditions. The studied parameters include the loading angle, axial compression ratio, the high-strength stirrups with small spacing, and the carbon-fiber-reinforced polymer (CFRP) wrapped column end or outer steel plate mesh at the end of the column. Low-cycle repeated loading tests were used to analyze the specimens’ seismic performance indices of hysteretic behavior, strength, stiffness, deformation capacity, and energy dissipation capacity. Results suggest that the OpenSees finite element program can sufficiently simulate the nonlinear response of the specimen. Oblique loading led to the increase of damage to the specimens and the deterioration of stiffness of the specimens, which was especially seen with the increase of the axial compression ratio. Accordingly, arranging high-strength stirrups with small spacing and the column end outer steel plate mesh both transform the failure mode from shear failure to bending shear failure. Additionally, wrapping the CFRP at the end of columns improves their strength but does not improve their deformation capacity. The demonstrated success of these strategies in improving the seismic performance of RC short columns under diagonal loads with high axial compression ratios can inform practical engineering applications.

scholarly journals Study of Seismic Behavior of RC Beam-Column Joints Strengthened by Sprayed FRP

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Zhao Yang ◽  
Yong Liu ◽  
Jiajia Li
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Rc Beam ◽  
Initial Stiffness ◽  
Axial Compression Ratio ◽  
Energy Dissipation Capacity ◽  
Strength And Stiffness

To study the seismic behavior of RC beam-column joints strengthened with sprayed FRP, five 1 : 2 reduced-scale specimens of joints were tested through quasi-static experiments. The failure modes, hysteretic curves, skeleton curves, strength, deformation, degradation of strength and stiffness, ductility, and energy dissipation capacity were studied. Furthermore, the effect of three main influencing factors including the sprayed FRP thickness, strengthened area, and axial compression ratio was analyzed in this paper as well. The results show that sprayed FRP strengthening can improve the seismic behavior of RC beam-column joints effectively. The increase of sprayed FRP thickness can lead to a better seismic performance for the joints. Strengthening area can affect the bearing capacity obviously. Higher axial compression ratio can increase the bearing capacity and initial stiffness, but it can make the deformation capacity and ductility decreased. The study can provide references to further research on the sprayed FRP material for strengthening of RC beam-column joints.

Effect of Axial Compression Ratio on Ductility and Bearing Capacity of Specially Shaped Columns with HRB500 Reinforcement

2012 ◽  
Vol 204-208 ◽  
pp. 1066-1069
Author(s):  
Yan Jun Li ◽  
Ping Liu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Ultimate Load ◽  
Deformation Capacity ◽  
Displacement Ductility ◽  
Yield Load ◽  
Axial Compression Ratio ◽  
Low Cyclic Loading ◽  
Specially Shaped Column

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.

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