scholarly journals Experimental Study on Hysteretic Behavior of the Overlapped K-Joints with Concrete Filled in Chord

2019 ◽  
Vol 9 (7) ◽  
pp. 1456 ◽  
Author(s):  
Wenwei Yang ◽  
Ruhao Yan ◽  
Yaqi Suo ◽  
Guoqing Zhang ◽  
Bo Huang
Keyword(s):  
Plastic Deformation ◽  
Energy Dissipation ◽  
Cyclic Loading ◽  
Bearing Capacity ◽  
Failure Modes ◽  
The United States ◽  
Hysteretic Behavior ◽  
Tensile Failure ◽  
Element Analysis ◽  
Better Than

Due to the insufficient radial stiffness of the steel tube, the cracking of the weld and the plastic deformation of the string often occur under the cyclic loading of the hollow section pipe joint. In order to avoid such a failure, the overlapped K-joints were strengthened by pouring different concrete into the chords. Furthermore, to explore the detailed effect of filling different concrete in a chord on the hysteretic behavior of the overlapped K-joints, six full-scale specimens were fabricated by two forms, which included the circular chord and braces, the square chord and circular braces, and the low cyclic loading tests, which were carried out. The failure modes, hysteretic curves and skeleton curves of the joints were obtained, and the bearing capacity, ductility and energy dissipation of the joints were evaluated quantitatively. The results showed that plastic failure occurs on the surface of the chord of the joints without filling concrete, while the failure mode of the joints filled with concrete in the chords was the tensile failure of the chords at the weld of the brace toe, and the compressive braces had a certain buckling deformation; The strengthening measures of concrete filled with chord can effectively improve the mechanical properties of the K-joints, the delay of the plastic deformation of the chord, and improve the bearing capacity of the K-joints. Contrarily, the ductility coefficient and the energy dissipation ratio of K-joints decreased with the concrete filled in the chord. The hysteretic behavior of the K-joints with a circular chord and brace was slightly better than that of the K-joints with a square chord and circular brace, and the hysteretic behavior of the K-joints strengthened with fly ash concrete, which was better than that of the K-joints strengthened with ordinary concrete. The results of ANSYS (a large general finite element analysis software developed by ANSYS Company in the United States) analysis agreed well with the experimental results.

Seismic Behavior Test of Recycled RC Frame Column with Different Axial Compression Ratios

2012 ◽  
Vol 517 ◽  
pp. 564-569
Author(s):  
Jin Song Fan ◽  
An Zhou ◽  
Li Hua Chen ◽  
Bing Kang Liu
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Failure Modes ◽  
Construction Materials ◽  
Recycled Concrete ◽  
Hysteretic Behavior ◽  
Static Test ◽  
Concrete Frame ◽  
Energy Dissipation Capacity

Recycled concrete is a kind of new construction materials, and now received more and more attention from researchers and engineers, since its application in engineering projects can well cater to the increasing requirements of development for economic and environment-friendly society. Based on the pseudo static test of five recycled reinforcement concrete frame columns with different experimental axial compression ratios from 0.3 to 0.65, their failure modes, failure mechanism, hysteretic behavior, skeleton curves, bearing capacity, rigidity, ductility and energy dissipation capacity were discussed. Some possible influence factors and disciplines were also selected and analyzed. The study indicates that recycled reinforcement concrete frame columns in the case of relative low axial compression ratios usually exhibited similar and steady mechanical properties with common concrete columns. With the increase of axial compression ratio, its ductility and energy dissipation capacity are decreased and destruction forms tended to obvious brittle fracture, though its bearing capacity could slightly rise. The test results and analysis also manifest recycled concrete had expectative application potentials in most case.

scholarly journals Hysteretic Behavior of Beam-to-Column Joints with Cast Steel Connectors

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Guofeng Xue ◽  
Wei Bao ◽  
Jin Jiang ◽  
Yongsong Shao
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Cast Steel ◽  
Hysteretic Behavior ◽  
Element Analysis ◽  
Rapid Repair ◽  
Practical Engineering ◽  
New Type ◽  
Column Joint ◽  
Energy Dissipation Capacity

This study proposed a beam-to-column joint equipped with a new type of cast steel connector. The cast steel connector concentrated the primary portion of the deformation and energy dissipation of the joint and was installed with full bolted connections, rendering it a replaceable energy dissipation component and facilitating the rapid repair of the joint after an earthquake. Three full-scale specimens were fabricated and tested to investigate the hysteretic behaviors of the proposed joints under cyclic loadings. The results showed that the proposed cast steel connector exhibited reliable ductility and energy dissipation capacity. The beam-to-column joints with cast steel connectors under appropriate configuration can limit the deformation to the cast steel connector and protect the remaining joint components from plastic deformation. A more detailed finite element analysis was performed to investigate the hysteretic behavior of the joint further. The FEM results illustrated that the thickness of the vertical leg of the cast steel connector can significantly influence the stiffness and bearing capacity of the joint. Meantime, it would improve the hysteretic behavior effectively. The proposed beam-to-column joints with cast steel connectors can achieve the requirement of stiffness and load-bearing capacity and can be widely applicable in practical engineering.

Comparative Analysis on Seismic Performance of Steel Frame with Different Forms of Symmetric Enhanced Nodes

2013 ◽  
Vol 790 ◽  
pp. 247-251
Author(s):  
Li Ting Dong ◽  
Yan Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Analysis ◽  
Energy Dissipation ◽  
Seismic Performance ◽  
Failure Modes ◽  
Hysteretic Behavior ◽  
Structural Form ◽  
Element Analysis ◽  
Energy Dissipation Capacity

Based on node test and finite element analysis results of four different structural form enhanced nodes,failure modes,hysteretic behavior,bearing capacity,ductility and energy dissipation capacity of nodes are analyzed comprehensively and comparatively for more in-depth exploration about the seismic performance of symmetric enhanced nodes.The results showed that all the symmetric enhanced nodes have full hysteretic curve and energy dissipation capacity. On the whole,The flange-plate reinforced node exhibit better seismic performance.

scholarly journals Experimental Study on Hysteretic Behavior of Double-Plate Reinforced Overlapped K-Joints

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Wenwei Yang ◽  
Shuntao Li ◽  
Ruhao Yan ◽  
Yaqi Suo
Keyword(s):  
Plastic Deformation ◽  
Cyclic Loading ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Force Model ◽  
Energy Depletion ◽  
Skeleton Curve ◽  
Hollow Section ◽  
Hysteretic Performance ◽  
Reinforcement Measures

The lifetime of hollow section tubular joints frequently can be shortened owing to the occurrence of the welded cracks and the plastic deformation of chords under the cyclic loading, because of the deficient radial bearing capacity of the steel tube. To avoid such failures, this paper proposes a novel method to strengthen the chord with double plates at the intersection of the chord and braces. To further investigate the efficiency of this strengthening method on hysteretic performance and energy depletion ability of the overlapped K-joints with hollow sections, two unreinforced K-joints and two reinforced K-joints were fabricated. By loading on the braces with collaborative cyclic loading, the joints failure modes, hysteresis curve, and skeleton curve were obtained. The bearing capacity, ductility, and energy depletion of the joints were assessed and the restoring force model of joints was proposed. The results show that the failure mode of the unreinforced joint is the plastic failure of the surface of the chord. For the K-RC1 (double-plate reinforced square hollow section tubular K-joints), cracks appeared at the junction weld between the through brace and the overlapped brace. However, cracks extended along the weld at the intersection of the chord and the through brace for K-CC1 (double-plate reinforced circular hollow section tubular K-joints). There is no obvious deformation on the chord surface of reinforced joints. Experimental results reveal that the mechanical properties of the joints can be improved effectively by such reinforcement measures and that the plastic deformation of the chord can also be restrained. Meanwhile, the reinforcement measures demonstrate the ability to avoid the risk of large stress concentration of the chord in the area where the braces and chords are intersected. The bearing capacity of the joint was increased; however, the ductility of the joint was weakened.

Experimental study on double-headed screw joints and their application in bamboo shear walls

2020 ◽  
pp. 136943322097177
Author(s):  
Qingfang Lv ◽  
Yi Ding ◽  
Ye Liu
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Shear Failure ◽  
Single Layer ◽  
Shear Walls ◽  
Shear Wall ◽  
Tensile Failure ◽  
Step Test ◽  
Double Shear

Due to the weak withdrawal capacities of conventional nail joints, using double-headed screw joints as reliable connections in bamboo structures is investigated for the first time. A two-step test program is presented in this paper. In the first step, a double shear test is carried out to investigate the influences of the end distance and bamboo grain direction on the performance of double-headed screw joints. The test shows that there are four main failure modes of double-headed screw joints: double-headed screw shear failure, bearing failure of the hole wall, tensile failure of the bamboo cover panel and shear failure of the cover panel end. In the second step of test, the proposed double-headed screw joints are applied to three single-layer single-span bamboo shear walls, and low-cycle reversed loading tests are applied to the walls with double-headed screw spacings of 50 mm, 100 mm and 150 mm. The failure mode, hysteretic behaviour and energy dissipation performance of the shear walls are discussed. Test results show that the two main failure modes of the bamboo shear walls are the tensile failure of the edge of the wall and shear failure of the double-headed screws. Among the different spacings, the bearing capacity and effective stiffness of the wall with a double-headed screw spacing of 50 mm are the largest, the ductility and energy dissipation capacity of the bamboo shear wall with a double-headed screw spacing of 100 mm are the largest, and the bearing capacity and ductility of the bamboo shear wall with a double-headed screw spacing of 150 mm are the worst.

Finite Element Analysis for Unstiffened Overlapped CHS KK-Joints Welded in Different Ways

2010 ◽  
Vol 163-167 ◽  
pp. 299-306 ◽  
Author(s):  
Xiu Li Wang ◽  
Wen Wei Yang ◽  
Lei Zou
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Low Frequency ◽  
Steel Structure ◽  
Structure Design ◽  
Hysteretic Behavior ◽  
Ultimate Capacity ◽  
Element Analysis ◽  
Finite Element Software ◽  
Better Than

The question whether hidden weld of unstiffened overlapped CHS (circular hollow sections) KK-joints is welded or un-welded is not clearly mentioned in China's steel structure design codes (GB50017-2003) .This paper mainly analyzes the influence of chord-to-brace diameter ratio β, diameter-to- ply ratio γ and brace-to-chord ply ratio τ to the ultimate bearing capacity of the joints with the hidden weld welded and un-welded. The influence of welded and un-welded hidden welds of the joints on hysteretic behavior under low frequency loading is analyzed , and hysteretic curve of the joints are obtained by the finite element software ANSYS. Side brace or opposite brace of the hidden weld of the joints has little influence on the failure modes and ultimate capacity of the joints. Hysteretic behavior of the joints with the hidden weld un-welded is much better than that of the welded.

scholarly journals A Finite Element Study on Compressive Resistance Degradation of Square and Circular Steel Braces under Axial Cyclic Loading

2021 ◽  
Vol 11 (13) ◽  
pp. 6094
Author(s):  
Hubdar Hussain ◽  
Xiangyu Gao ◽  
Anqi Shi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cyclic Loading ◽  
Slenderness Ratio ◽  
Hysteretic Behavior ◽  
Element Analysis ◽  
Section Shape ◽  
Axial Cyclic Loading ◽  
Global Buckling ◽  
Parametric Studies

In this study, detailed finite element analysis was conducted to examine the seismic performance of square and circular hollow steel braces under axial cyclic loading. Finite element models of braces were constructed using ABAQUS finite element analysis (FEA) software and validated with experimental results from previous papers to expand the specimen’s matrix. The influences of cross-section shape, slenderness ratio, and width/diameter-to-thickness ratio on hysteretic behavior and compressive-tensile strength degradation were studied. Simulation results of parametric studies show that both square and circular hollow braces have a better cyclic performance with smaller slenderness and width/diameter-to-thickness ratios, and their compressive-tensile resistances ratio significantly decreases from cycle to cycle after the occurrence of the global buckling of braces.

scholarly journals Research on Failure Characteristics of Concrete Three-Point Bending Beams with Preexisting Cracks in Different Positions Based on Numerical Simulation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Liuqun Zhao ◽  
Li Zheng ◽  
Hui Qin ◽  
Tiesuo Geng ◽  
Yonggang Tan ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Failure Process ◽  
Engineering Application ◽  
Tensile Failure ◽  
Engineering Structures ◽  
Failure Characteristics ◽  
Three Point Bending ◽  
Wide Range

Concrete three-point bending beams with preexisting cracks are widely used to study the growth process of I-II mixed mode cracks. Studying the failure characteristics of preexisting cracks at different locations on concrete three-point bending beams not only has important scientific significance but also has a wide range of engineering application backgrounds in the safety assessment of engineering structures. In this paper, through several numerical experiments, the influence of preexisting cracks at different positions on the failure characteristics of concrete three-point bending beams is studied, and three typical failure modes are obtained. The failure process of the specimens with three typical failure modes is discussed in detail, and it is pointed out that the crack failure mode is tensile failure. The change trends of bearing capacity, acoustic emission quantity, and acoustic emission energy of three typical failure modes are analyzed. The maximum bearing capacity, the maximum acoustic emission quantity, and energy of three failure modes of concrete three-point bending beams generally show an increasing trend.

Experimental study on the seismic performance of traditional timber mortise-tenon joints with different looseness under low-cyclic reversed loading

2018 ◽  
Vol 22 (6) ◽  
pp. 1312-1328 ◽  
Author(s):  
Jianyang Xue ◽  
Rui Guo ◽  
Liangjie Qi ◽  
Dan Xu
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Failure Modes ◽  
Artificial Defect ◽  
Reversed Loading ◽  
Energy Dissipation Capacity ◽  
Strength And Stiffness ◽  
Seismic Behaviors ◽  
Damage Type ◽  
Better Than

The majority of existing ancient timber structures have different degrees of damage. The looseness of mortise-tenon joints is a kind of typical damage type. In order to study the influence of looseness on the seismic performance of mortise-tenon joints, six through-tenon joints and six dovetail-tenon joints with scale 1:3.2 were fabricated according to the requirements of the engineering fabrication method of Chinese Qing Dynasty. Each type of joints consisted of one intact joint and five artificial loose joints, and the artificial defect was made to simulate looseness by cutting the tenon sectional dimension. Based on experiments of two types of joints under low-cyclic reversed loading, the seismic behaviors of joints such as failure modes, hysteretic loops and skeleton curves, strength and stiffness degradation, and energy dissipation capacity were studied. Moreover, the comparative analyses of seismic performance between two types of joints were carried out. The variation tendency of seismic behaviors of two types of joints has similarities, and there are some differences due to their different structural styles. The results indicate that squeeze deformation between tenon and mortise of two types of joints occurred. The shape of hysteretic loops of two types of joints is reverse-Z-shape, and the pinching effect of hysteretic loops becomes more obvious with the increase in looseness, among which of through-tenon joints is more obvious than that of dovetail-tenon joints. The carrying capacity, stiffness, and energy dissipation capacity of loose joints are significantly lower than that of the intact one, and the energy dissipation capacity of dovetail-tenon joints is better than that of through-tenon joints. The rotation angles of two types of joints can reach 0.12 rad, and the loose joints still have great deformation capacity.

scholarly journals Behavior of Rectangular-Sectional Steel Tubular Columns Filled with High-Strength Steel Fiber Reinforced Concrete Under Axial Compression

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2716 ◽  
Author(s):  
Shiming Liu ◽  
Xinxin Ding ◽  
Xiaoke Li ◽  
Yongjian Liu ◽  
Shunbo Zhao
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Local Buckling ◽  
Steel Tube ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Energy Dissipation Capacity

This paper studies the effect of high-strength steel fiber reinforced concrete (SFRC) on the axial compression behavior of rectangular-sectional SFRC-filled steel tube columns. The purpose is to improve the integrated bearing capacity of these composite columns. Nine rectangular-sectional SFRC-filled steel tube columns and one normal concrete-filled steel tube column were designed and tested under axial loading to failure. The compressive strength of concrete, the volume fraction of steel fiber, the type of internal longitudinal stiffener and the spacing of circular holes in perfobond rib were considered as the main parameters. The failure modes, axial load-deformation curves, energy dissipation capacity, axial bearing capacity, and ductility index are presented. The results identified that steel fiber delayed the local buckling of steel tube and increased the ductility and energy dissipation capacity of the columns when the volume fraction of steel fiber was not less than 0.8%. The longitudinal internal stiffening ribs and their type changed the failure modes of the local buckling of steel tube, and perfobond ribs increased the ductility and energy dissipation capacity to some degree. The compressive strength of SFRC failed to change the failure modes, but had a significant impact on the energy dissipation capacity, bearing capacity, and ductility. The predictive formulas for the bearing capacity and ductility index of rectangular-sectional SFRC-filled steel tube columns are proposed to be used in engineering practice.

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