scholarly journals Experimental and Numerical Investigation of Concrete-Filled Double-Skin Steel Tubular Column for Steel Beam Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Dongfang Zhang ◽  
Junhai Zhao ◽  
Yufen Zhang
Keyword(s):  
Failure Modes ◽  
Compressive Force ◽  
Load Level ◽  
Steel Beams ◽  
Initial Stiffness ◽  
Element Analysis ◽  
Fea Model ◽  
Failure State ◽  
Double Skin ◽  
The Moment

This paper presents a new type of joint for connecting steel beams with a concrete-filled double-skin steel tubular (CFDST) column. Four half-scale specimens of the joint with different specifications were constructed and tested under a constant axially compressive force with vertical low-reversal loads applied to the beam ends to examine their failure modes and hysteretic behaviors. The beam hinging mechanism of the joint was observed in the radian area of the horizontal end plates. The proposed connection was found to exhibit good energy dissipation capabilities with its limit rotation in the failure state reaching 0.05 rad, thus satisfying the FEMA-350 ductility requirement of ≥0.03 rad for seismic resistance. A finite element analysis (FEA) model of the joint was also established and validated by comparing its predictions with experimental results. The FEA model was used to investigate the effects of different parameters such as the stiffened height of the web anchorage plate, axial load level, steel and concrete strengths, steel ratio on the moment-rotation relationship, and initial stiffness of the connection. This paper presents some important design considerations of the connection, as well as aspects requiring further study.

scholarly journals Moment Resisting Connection with Curved Endplates: Behaviour Study

2021 ◽  
Vol 11 (4) ◽  
pp. 1520
Author(s):  
Andrej Mudrov ◽  
Antanas Šapalas ◽  
Gintas Šaučiuvėnas ◽  
Kęstutis Urbonas
Keyword(s):  
Experimental Tests ◽  
Steel Beams ◽  
Initial Stiffness ◽  
Flat Plates ◽  
Element Analysis ◽  
Hollow Section ◽  
Moment Resisting ◽  
The Moment ◽  
Circular Hollow Section ◽  
Parametric Finite Element Analysis

This article provides a behaviour analysis of moment resisting joints with curved endplates. This is a new type of connection that can be used for joining steel beams to the circular hollow section (CHS) columns by means of bolts. Some researchers apply the Eurocode model without considering the differences in calculation schemes and assumptions, such as by using the general model of an equivalent T-stub in tension. Consequently, many of the existing behaviour studies are somewhat misleading, thus there is a need for further research. Apart from the absence of analytical methods that are devoted to predicting the initial stiffness and strength of the curved T-stub, other technical difficulties were encountered, such as gaps between the endplate and the column, as well as the initial pre-loading force of the bolts. In the previous studies, endplates were manufactured by rolling flat plates to the precise curvature which resulted in firm contact. In contrast, in this study, endplates were manufactured from a standard CHS tube, which led to significant initial gaps. Meanwhile, in terms of preloading force, it was found that it affected the moment resistance of the joint. This paper discusses problems associated with ongoing researches and presents experimental tests of the two connections. The obtained results were further used in the parametric finite element analysis (FEA) to determine the effect of the gaps and preloading force of the bolts on the moment resistance and initial rotational stiffness of the joint. The results indicate that the behaviour of curved plated connections is exceedingly complex and that the preloading force is the key factor, therefore, it should be controlled.

scholarly journals Seismic Damage Investigation of Spatial Frames with Steel Beams Connected to L-Shaped Concrete-Filled Steel Tubular (CFST) Columns

2018 ◽  
Vol 8 (10) ◽  
pp. 1713 ◽  
Author(s):  
Jicheng Zhang ◽  
Yong Li ◽  
Yu Zheng ◽  
Zhijie Wang
Keyword(s):  
Finite Element ◽  
Frame Structures ◽  
Steel Beams ◽  
Element Analysis ◽  
Testing Specimen ◽  
Tubular Columns ◽  
Finite Element Software ◽  
Fea Model ◽  
Composite Frames ◽  
Cfst Columns

Currently, the frame structures with special-shaped concrete-filled steel tubular columns have been widely used in super high-rise buildings. Those structural members can be used to improve architectural space. To investigate the seismic behavior of spatial composite frames that were constructed by connecting steel beams to L-shaped concrete-filled steel tubular (CFST) columns, a finite element analysis (FEA) model using commercial finite element software ABAQUS was proposed to simulate the behavior of the composite spatial frames under a static axial load on columns and a fully-reversed lateral cyclic load applied to frames in this paper. Several nonlinear factors, including geometry and material properties, were taken into account in this FEA model. Four spatial specimens were designed, and the corresponding experiments were conducted to verify the proposed FEA model. Each testing specimen was two-story structure consisting of eight single span steel beams and four L-shaped CFST columns. The test results showed that the proposed FEA model in this paper could evaluate the behavior of the composite spatial frames accurately. Based on the results of the nonlinear analysis, the stress developing progress of columns is investigated. The load transferring mechanism and failure mechanism are also determined. The results are discussed and conclusions about the behavior of those spatial frame structures are presented.

Seismic Performance of Medium Thick-Walled Cold-Formed Steel Top-and-Seat Angle Joint

2014 ◽  
Vol 501-504 ◽  
pp. 1609-1614
Author(s):  
Zhong Peng ◽  
Jun Huang ◽  
Shao Bin Dai ◽  
Ji Xiong Liu
Keyword(s):  
Energy Dissipation ◽  
Failure Modes ◽  
Mechanical Performance ◽  
High Strength ◽  
Initial Stiffness ◽  
Element Analysis ◽  
Equivalent Viscous Damping ◽  
Seat Angle ◽  
Cold Formed Steel ◽  
Energy Dissipation Capacity

3 medium thick-walled cold-formed steel top-and-seat angle joints were designed. The ABAQUS nonlinear finite element analysis on earthquake resistance behaviors of the joints were conducted under low cyclic loading. The results indicate that the failure processes and failure modes of 3 specimens are basically the same, the destruction of joints derive from buckling deformation of the top-and-seat angle and buckling of the steel beam flanges; the shapes of hysteresis curves of all specimens are obvious pinch together and present spindle, the displacement ductility factors are greater than 5.5, the equivalent viscous damping factors are greater than 0.158, all the specimens possess good energy dissipation capacity. The secant stiffness variations are almost similar, each specimen represents significant degradation. Increase the thickness of angle and diameter of high-strength bolt can improve the mechanical performance of the joints. Increase the bolt diameter, the ductility, energy dissipation capacity and initial stiffness enhance obviously, however, there is no apparent effect while increasing the thickness of angle.

scholarly journals Cyclic Testing of Concrete-Filled Double-Skin Steel Tubular Column to Steel Beam Joint with RC Slab

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Dongfang Zhang ◽  
Junhai Zhao ◽  
Shuanhai He
Keyword(s):  
Energy Dissipation ◽  
Failure Modes ◽  
Compressive Force ◽  
Steel Beam ◽  
Composite Joints ◽  
Equivalent Viscous Damping ◽  
Rc Slab ◽  
Bare Steel ◽  
Double Skin ◽  
Rc Slabs

The design of composite joints for connecting concrete-filled double-skin tubular (CFDST) columns to steel beams supporting reinforced concrete (RC) slabs is presented in this paper. Five half-scale specimens were designed, including four composite joints with RC slab and one bare steel beam joint, and were tested under a constant axially compressive force and lateral cyclic loading at the top end of the column to evaluate their seismic behavior. The main experimental parameters were the construction of the joint and the type of the column. The seismic behaviors, including the failure modes, hysteresis curves, ductility, strength and stiffness degradation, and energy dissipation, were investigated. The failure modes of the composite joints depended on the joint construction and on the stiffness ratio of beams to columns. Joints of stiffening type had significantly higher load-bearing and deformation capacities than joints of nonstiffening type. Compared with the bare steel beam joint, the bearing capacities of the composite joints with RC slabs were markedly increased. The composite action was remarkable under sagging moments, resulting in larger deformation on the bottom flanges of the beams. Overall, most specimens exhibited full hysteresis loops, and the equivalent viscous damping coefficients were 0.282∼0.311. The interstory drift ratios satisfied the requirements specified by technical regulations. Composite connections of this type exhibit excellent ductility and favorable energy dissipation and can be effectively utilized in superhigh-rise buildings erected in earthquake zones.

scholarly journals Numerical Behaviour of Composite K-Joints Subjected to Combined Loading and Corrosive Environment

2018 ◽  
Author(s):  
Chao Hou ◽  
Shameer Saleh ◽  
Lin-Hai Han ◽  
You-Xing Hua
Keyword(s):  
Failure Modes ◽  
Full Range ◽  
Steel Tube ◽  
Combined Loading ◽  
Truss Structures ◽  
Mechanism Analysis ◽  
Corrosive Environment ◽  
Range Analysis ◽  
Element Analysis ◽  
Fea Model

Concrete filled steel tubular (CFST) truss structures have been adopted in various infrastructures worldwide for past several decades. Application of CFST truss is more prevalent especially in areas where harsh marine condition with chloride corrosion limits the design life of structures. Design of joints is one of the most complicated issues in CFST truss structures; and it becomes more critical when corrosion causes section loss in the outer steel tube. Improved designs in terms of economy and durability need to be suggested based on rational research on composite K-joints in corrosive environment, whilst such research is very limited up until now. This paper thus attempts to study the behaviour of circular concrete filled steel tubular (CFST) K-joints under combined effect of long-term loading and corrosion. A finite element analysis (FEA) model is presented and verified against existing test results. The model is then utilized to perform mechanism analysis of CFST K-joints under varying loading and corrosion situations. Failure modes, detailed propagation of yield and stress distribution between the core concrete in chord and the tubular steel is investigated, based on which a favourable mode of failure is suggested in terms of maximum joint capacity. Finally, a full range analysis of the load-deformation characteristics is carried out for various corrosion situations, with the corresponding joint strength as well as ductility predicted.

scholarly journals An Experimental and Numerical Study of Repairs on Composite Substrates with Composite and Aluminum Doublers Using Riveted, Bonded, and Hybrid Joints

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2978 ◽  
Author(s):  
Pitta ◽  
Roure ◽  
Crespo ◽  
Rojas
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Numerical Study ◽  
Progressive Failure ◽  
Adhesive Bond ◽  
Element Analysis ◽  
Fea Model ◽  
Composite Substrate ◽  
Riveted Joints ◽  
Hybrid Joints

In this work, experimental and numerical analyses of repairs on carbon fiber reinforced epoxy (CFRE) substrates, with CFRE and aluminum alloy doublers typical of aircraft structures, are presented. The substrates have a bridge gap of 12.7 mm (simulated crack), repaired with twin doublers joined with riveted, adhesive bonded, and hybrid joints. The performance of the repairs using different doubler materials and joining techniques are compared under static loading. The experimental results show that riveted joints have the lowest strength, while adhesive bonded joints have the highest strength, irrespective of the doubler material. Finite element analysis (FEA) of the studied joints is also performed using commercial FEA tool Abaqus. In the FEA model, point-based fasteners are used for the rivets, and a cohesive zone contact model is used to simulate the adhesive bond. The FEA results indicate that the riveted joints have higher tensile stresses on the metal doublers compared to the composite doublers. As per the failure modes, interestingly, for hybrid joints using composite doublers, the doublers fail due to net-section failure, while, for hybrid joints using metal doublers, it is the composite substrate that fails due to net-section failure. This suggests vulnerability of the composite structures to mechanical fastener holes. Lastly, the Autodesk Helius composite tool is used for prediction of first-ply failure and ply load distribution, and for progressive failure analysis of the composite substrate.

scholarly journals Performance of Special-Shaped Concrete-Filled Square Steel Tube Column under Axial Compression

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Zhen Wang ◽  
Xuejun Zhou ◽  
Fangshuai Wei ◽  
Mingyang Li
Keyword(s):  
Yield Strength ◽  
Failure Modes ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Local Buckling ◽  
Steel Tube ◽  
Element Analysis ◽  
Fea Model ◽  
Compressive Performance ◽  
Square Steel Tube

The axial compressive performance of novel L-shaped and T-shaped concrete-filled square steel tube (L/T-CFSST) column was assessed in this study. Ten L/T-CFSST columns were tested to failure under axial load. The experimental data were used to determine various failure modes, bearing capacities, and load-displacement curves. The test parameters included the section form, steel tube thickness, steel yield strength, and slenderness ratio. The axial compressive performance of the L/T-CFSST column proved favorable, and each square steel tube showed strong cooperative performance. The failure mode of the stub column specimen (H/D ≤ 3) was strength failure caused by local buckling of the steel tube and that of the medium-long column member (H/D > 3) was instability failure caused by overall bending of the specimen. A finite element analysis (FEA) model was established and successfully validated by comparison against the test results. Based on the FEA model, parametric analyses were conducted to investigate the effects of steel tube thickness, concrete strength, steel yield strength, and slenderness ratio. The ultimate loads obtained from the experiments and FEA were compared to the results calculated by the available design codes. A formula was established to calculate the axial compressive strength and stability bearing capacity of the L/T-CFSST column accordingly. The calculation results are in close agreement with the FEA and experimental results, and the proposed formula may provide a workable reference for practicing engineers.

Analysis of Mechanical Behaviour of the Concreat Filled Double Skin Steel TubesK-Joint

2013 ◽  
Vol 849 ◽  
pp. 417-421
Author(s):  
Yu Zhuo Jia ◽  
Chen Feng Zhou ◽  
Cheng Cheng Li ◽  
Liang Zhang
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Power Transmission ◽  
Transmission Tower ◽  
Analysis Software ◽  
Steel Tubes ◽  
Element Analysis ◽  
Bond Slip ◽  
The Finite Element Analysis ◽  
Double Skin

In recent years, a new kind struct of concreat-filled skin steel tubesConcrete-Filled Double Skin Steel Tubes (CFDST),are more used in transmission line constructions. It is a kind of hollow structs, which concentric placed the double skin steel tubes, and filling with concrete between the two steel tubes[.CFDST K-joints on power transmission tower must be finite element simulated to research the capacity of bond-slip between the steel and concrete by the finite element analysis software-ANSYS 10.0 in this paper, and finally gets the ultimate bearing capacity and failure modes of K-joints.

Bending Capacity of Corroded Pipeline Subjected to Internal Pressure and Axial Loadings

2018 ◽  
Author(s):  
Jie Gao ◽  
Zengli Peng ◽  
Xin Li ◽  
Jing Zhou ◽  
Wenxing Zhou
Keyword(s):  
Internal Pressure ◽  
Local Buckling ◽  
Compressive Force ◽  
Bending Moment ◽  
Corrosive Media ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Offshore Pipelines ◽  
Bending Capacity ◽  
The Moment

Offshore pipelines operating in a harsh environment are usually subjected to combinations of bending moment and axial loadings in addition to internal pressure. Due to the corrosive media transported in the pipelines and corrosive substances within seawater and soil outside the pipelines, local corrosion defects will generate on the pipeline’s inner and outer walls, reducing its ultimate bearing capacity. This paper presents a series of full-scale failure tests and nonlinear finite element analysis (FEA) to study the bending capacity and failure mode of corroded pipelines with outside locally-thinned-areas (LTAs) subjected to combinations of internal pressure, axial compressive force and bending moment. The LTAs are loaded in compression to simulate corrosion. Material tests of API 5L X56 seamless pipe steel were conducted and the stress-strain relationship was obtained. FEA results of the moment versus curvature relation, bending capacity and local buckling behavior of each specimen model matched the experimental results very well, validating the accuracy of this simulation. Additional FEA is then performed to investigate the effect of corrosion geometric parameters, such as corrosion depth, corrosion width, and corrosion length, on the ultimate moment. Among them, the width is of the greatest impact, followed by is the depth, the length impact can be ignored.

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