Binding Bars Research Articles

Endophilin-Dynamin Complex Assembly - A General Mechanism of Membrane Remodeling Control

Endophilin belongs to a group of proteins containing membrane binding and bending BAR domains. Neuronal-specific endophilin A1 mediates membrane bending in association with dynamin 1-catalyzed membrane fission. In a previous study, we show that endophilin A1 co-localizes with dynamin 1 on necks of clathrin-coated pits in nerve terminals and assembles into a complex with dynamin 1 on tubulated liposomes in vitro. Using cryo-EM and iterative helical real space reconstruction (IHRSR) we have generated a preliminary 3D density map of the endophilin A1–dynamin 1 complex.

Fire performance of blind bolted composite beam to column joints

Blind bolts can be used to connect steel beams to concrete filled steel tubular (CFST) columns, and the obtained composite joints have relatively high initial stiffness, flexural resistance, and ductility at ambient temperature. However, very limited research has been conducted on the fire performance of the blind bolted composite joints. In this paper, eight full-scale blind bolted joints were tested to study their fire performance. The test parameters include: (a) whether fire protection is applied to the steel beam or not; (b) beam load ratio (0.25 and 0.5); (c) type of steel used for the column (stainless or carbon steel); and (d) with or without binding bars in the connection region. The test results indicated that the joint failure was mainly dominated by flexural failure of the steel beam near the panel zone. In general, the blind bolted joints demonstrated very good performance in fire, and no bolt shank fracture or bolt pull-out failure was observed in any joint test. The beam protection or reduction of the beam load significantly increased the fire resistance of the joint, whereas the presence of the binding bars or the type of the steel tube had only moderate influence on the fire resistance.

Hysteretic behavior of square CFT columns with binding bars

This paper presents the hysteretic behavior of square concrete-filled steel tubular (CFT) stub columns with binding bars. A total of ten square CFT stub columns including eight specimens with binding bars and two specimens without binding bars were tested under constant axial load and cyclic lateral loads. The effects of the axial load level and the spacing of binding bars on the hysteretic behavior were investigated carefully. Experimental results demonstrate that the specimens with binding bars show higher lateral bearing capacity, higher stiffness, higher ultimate deformation capacity and better energy-dissipation capacity compared with those without binding bars. In addition, the initial local buckling for specimens with binding bars is significantly delayed by the binding bars. Furthermore, the lateral bearing capacity, the ultimate deformation capacity, the energy-dissipation capacity and the stiffness of the specimens with binding bars are significantly improved with the spacing of binding bars decreasing. The ultimate deformation capacity decreases with an increase in axial load levels while the energy-dissipation capacity increases with an increase in axial load levels. Finally, the fiber element analysis for all specimens is carried out. The calculated envelope curves and the calculated hysteretic curves of the specimens by the fiber element analysis are in good agreement with the experimental results.

Axial compression performance of steel/bamboo composite column

Abstract A new type of thin-walled steel tube/bamboo plywood hollow composite column with binding bars (SBCCB) that used transverse binding bars to reinforce the composite column was developed. The compression performance of 4 specimens with larger slenderness ratio was tested to examine the failure mode of the SBCCBs. The results indicated that the compression failure modes are mainly crushing failure of the bamboo plywood material, partial debonding failure of the adhesion interface and buckling instability failure; the ultimate bearing capacity of the specimens is not only related to net cross-sectional area and slenderness ratio, but also greatly affected due to binding bars. Transverse binding bars can ensure the integrity of the composite column, effectively reduce the debonding failure of the adhesion interface and significantly improve the load-bearing capacity of the SBCCBs.

Experimental study on blind bolted connections to concrete-filled stainless steel columns

This paper studies the performance of blind bolted connections to concrete-filled stainless steel tubular columns. An experimental investigation was conducted on seven full-scale joints to study the effects of the following parameters: (a) presence of the floor slab or not; (b) with or without binding bars in the connection region; (c) type of steel used for the column (stainless or carbon steel); and (d) loading type (monotonic or cyclic). The experimental results demonstrated the good performance of the blind bolts in this type of connection. No bolt shank fracture was observed in any of the test specimens. The presence of the binding bars slightly enhanced the performance of the blind bolted connections, whereas the presence of composite slabs significantly affected the failure mode, initial stiffness, flexural resistance, and rotation capacity of the joints. Owing to the use of flush end plates, the joint without floor slab can be classified as nominally pinned joint according to EC3. But in the presence of the floor slab, the joint nearly reached its full strength and the stiffness was also significantly increased close to the limit for rigid sway frames. In addition, the test results indicated that the material type of the steel tube had no obvious influence on the joint performance. In contrast, the cyclic loading led to slightly decreased joint strength, but had more obvious detrimental influence on the joint stiffness.

Seismic performance of square, thin-walled steel tube/bamboo plywood composite hollow columns with binding bars

A thin-walled steel tube/bamboo plywood composite hollow column with binding bars (SBCCB) was developed using transverse binding bars to reinforce a thin-walled steel tube and bamboo plywood composite hollow column. Low reversed cyclic loading tests were performed on 9 SBCCB specimens to observe the damage process and morphology in the SBCCBs. The effects of the slenderness ratio, the net cross-sectional area of the bamboo plywood, the assembly patterns of the cross sections, and the binding bars on the stress and seismic performance were investigated. The results show that the main failure modes of the SBCCBs were cracking of different adhesion interfaces at the base of the column and fracturing of the bamboo plywood. The cross-sectional assembly pattern has a significant effect on the failure modes; increasing the cross-sectional area and the slenderness ratio of the composite column will dramatically improve the seismic performance of the SBCCBs. SBCCBs have excellent elastic deformation and seismic energy consumption characteristics. The binding bars ensure the integrity of the specimen and inhibit the failure of the adhesion interface at the base of the column. Finally, based on the measurement of the axial pressure and the stress-strain curve within elastic range of the composite columns, a simplified mechanical model and a calculation method for bearing capacity was formulated. The calculation values of bearing capacity agree well with the experimental ones, and calculation method can be used to provide guidance for engineering applications of a SBCCB.

Lateral load-carrying capacity analyses of composite shear walls with double steel plates and filled concrete with binding bars

A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars (SCBs). Nonlinear finite element models of SCBs were established by using the finite element tool, Abaqus. Tie constraints were used to connect the binding bars and the steel plates. Surface-to-surface contact provided by the Abaqus was used to simulate the interaction between the steel plate and the core concrete. The established models could predict the lateral load-carrying capacity of SCBs with a reasonable degree of accuracy. A calculation method was developed by superposition principle to predict the lateral load-carrying capacity of SCBs for the engineering application. The concrete confined by steel plates and binding bars is under multi-axial compression; therefore, its shear strength was calculated by using the Guo-Wang concrete failure criterion. The shear strength of the steel plates of SCBs was calculated by using the von Mises yielding criterion without considering buckling. Results of the developed method are in good agreement with the testing and finite element results.

Restoring Force Model of Concrete-Filled Square Steel Tubular Columns with Binding Bars

This paper presents a trilinear restoring force model based on the test results of two square concrete-filled steel tubular (CFT) stub columns without binding bars and eight square CFT stub columns with binding bars subjected to constant axial load and cyclic lateral load. The effects of binding bars and axial load level on the specimens are considered to determine the feature points of the skeleton curves. Calculation formulas for the characteristic parameters of the model, including the yield load, the peak load and the ultimate load, are given by analyzing the influence of the confinement factor of steel tube, the confinement coefficient of binding bars and the axial load level. Additionally, the hysteretic rule under cyclic lateral load is confirmed. The predicted hysteretic cures and skeleton curves based on the proposed model are in good agreement with the experimental results.

Cyclic behaviour of novel blind bolted joints with different stiffening elements

Because of the difficulty of accessing the interior of structural hollow sections, emerging technology using blind bolts has been recently developed for fabricating connections to concrete-filled steel tubular (CFST) columns. However, two issues limit the structural benefits of this joint system including the limited transfer of hogging moment and high susceptibility of the steel tube to local failure. Therefore, the authors proposed four methods to enhance the CFST column’s stiffness in the connection region, namely, using inner binding bars, welding two internal rings, externally welding two C-shaped channels, and internally embedding a short segment of I-section in the steel tube. A total of 6 joints were tested under cyclic loading accordingly. The experimental results are analysed in this paper to evaluate the efficiency of different stiffening methods. It indicates that the C-shaped channels and embedded I-section are very effective in enhancing the performance of the joint, and the joint’s strength and deformation capacity can be significantly improved with large bending deformation developed in the end plate. In contrast, welding binding bars or internal rings has only moderate influence on the joint performance.

Mechanical Behavior of Rectangular CFT Stub Column with Binding Bars Subjected to Eccentric Load

Mechanical Behavior of Rectangular CFT Stub Column with Binding Bars Subjected to Eccentric Load

Research on Concrete-Filled Rectangular Steel Tube Stiffeners and Axial Compression Bearing Capacity

Concrete-filled rectangular steel tube four sides restraint effect on the core concrete was weaker than the corner, which made the effect not significant. The paper studied a new kind of stiffening rib –PBL stiffener to strengthen restraint effect of concrete-filled rectangular steel tube , and evaluated its advantages compared with other stiffening ribs. 9 PBL stiffened concrete-filled rectangular steel tube columns under axial compressive load were tested. It also collected the test with other stiffened rids, such as straight ribs, binding bars, knee brace, steel reinforcement cage, steel bar stiffeners, saw tooth shaped stiffeners, stitching straight stiffeners and no rib concrete filled rectangular steel tube to compare. It evaluated increasing coefficient of bearing capacity by stiffening ribs. The results showed that: the PBL stiffeners and binding bar of concrete-filled rectangular steel tube bearing capacity was greater than other reinforcement measures by more than 20%; PBL stiffener could be a new prominent type of stiffener because of its excellent mechanical performance and simple construction.

Numerical Analysis on Square CFT Stub Columns with Binding Bars under Cyclic Loading Based on OpenSEES

In order to study the seismic behavior of square concrete-filled steel tubular (CFT) columns with binding bars under cyclic lateral load, numerical simulation is carried out based on the finite element software OpenSEES. The influence factors of seismic performance on square CFT columns with binding bars were studied. The results indicate that the analysis results exhibit good agreement with the experiment data. The axial load level is the main factor that influences the envelope curve. The stiffness decreases with the incresing of axial load level, while the ultimate lateral load increases with the axial load level less than 0.2, and decreases with the axial load level more than 0.3. The thickness of steel tube has a significant influence on the ultimate lateral load, while has little impact on the shape of envelope curve.

Experimental Investigation of Stiffened Square CFST Columns under Axial Load

Abstract: 7 square steel tubular columns were tested to discuss the ultimate axial bearing capacity, ductility performance and the steel consumption under stiffened by steel belts and binding bars of different cross-sections. Test results indicate that only by increasing fewer amounts of steel usage, stiffened square CFST columns with binding bars can not only improve the overall effects of restraint and alleviate regional local buckling between the binding bars, but also improve the bearing capacity of concrete filled square steel tubular columns. The utility benefits and the economical benefit is considerable, deserving extensive use.

Investigate on Axial Load Behaviors of T-Shaped CFT Stub Columns with Binding Bars

. Abstract. Tests on TCFT-WB, including 11 specimens with binding bars and 5 without binding bars under axial compression were carried out. The effects of parameters on the behavior of specimens such as failure mode, bearing capacity and ductility are analyzed to provide experimental data for the following research. The formula to calculate ultimate strength of TCFT-WB columns under axial compression are deduced from the constitutive relationship of TCFT-WB. The calculated results are compared with those calculated by FEM analyses, showing the proposed formula can give reasonable predictions on the ultimate strength of TCFT-WB stub columns under axial compression.

Experiment on T-Shaped CFT Stub Columns with Binding Bars Subjected to Axial Compression

To improve the mechanical behavior of T-shaped concrete-filled steel tubular (T-CFT) column, the method that setting binding bars along the height of steel tube is proposed. Five T-CFT stub columns with binding bars and another two without binding bars subjected to axial compression were tested. The influences of the spacing and diameter of binding bars on the failure modes, maximum strength, and ductility of T-CFT stub columns are investigated. The experimental results demonstrate that by setting binding bars or decreasing the spacing of binding bars, the buckling modes of the steel plates are changed, the local buckling of the steel plates is postponed, and the confinement effects on the core concrete can be improved significantly. By setting binding bars, the bearing capacity and ductility of the columns are enhanced by 1.17 and 3.38 times at most, respectively. By increasing the diameter of binding bars, the ductility of the columns is improved, but the bearing capacity and buckling strength cannot be improved when the diameter is large enough.

Research on Behavior of Rectangular CFST Stub Columns with Binding Bars under Axial Compression

The constitutive model of core concrete was proposed, which was suitable for finite element (FE) analysis of rectangular concrete-filled steel tubular (CFST) columns with binding bars. Based on the ABAQUS FE platform, the USDFLD subroutine was compiled, which could consider the changing of Poisson ratio of many materials in loading process. A FE model was developed and used to simulate the rectangular CFST columns with binding bars. The mechanical behavior were analyzed for stress versus strain relationship curves, confined effect among steel tube, core concrete and binding bars, longitudinal stress distributions of core concrete. The results show that the FE results simulated by using constitutive relationship of core concrete of this paper are in good agreement with test results. The local buckling of steel tube is delayed which can make the yield of steel tube occur before ultimate strength of specimens, the concrete confinement of the corner regions and central regions is improved, the longitudinal stress of concrete is increased and the capacity and ductility of specimens are improved, by setting binding bars and decreasing the binding bars spacing.

Study on Bend Performence of Binding Bars Prestressed Steel Box Concrete Beam

Put forward binding bars prestressed concrete filled steel box girder and analyses it’s advantage, Study on the bending moment by the fiber model method to analyze the beam-Curvature and load-Relation curves of deflection theory.Through the finite element software analysis of prestressed concrete steel box beam prestressed concrete filled steel tubes and four ways to set binding bars the ultimate bearing capacity of the beam,Analysis of the influence of the thickness of the steel plate and rod diameter, constraint, constraint rod axial spacing on various beam flexural capacity.The results show that,Binding bar has more advantages for prestressed concrete steel box using a thin plate bending ability improvement,Diameter, spacing of the binding bars binding bars as long as not bending capacity of prestressed concrete with binding bars of steel box beam structure under the condition of impact.

Research on the Axial Compressive Performance of the Concrete-Filled Steel Shear Wall with Binding Bars

The concrete-filled steel shear wall with binding bars is a new kind of lateral force resisting structure, which assembles binding bars with certain spacing. The behaviors of the structure under axial compression, containing bearing capacity and ductility, are studied by the software ABAQUS. Some factors as length-width ratio, bar spacing, steel thickness and material's strength grade, are taken into account. The results show that the axial compressive bearing capacity factor λ increases with length-width ratio b/t increasing; the factor λ, the ductility factor DI and the vertical displacement decrease with bar spacing d increasing; the bearing capacity factor of steel plate λs and DI increase while the factor λ decreases with steel thickness ts increasing; and with the concrete's strength grade and steel's strength grade improving respectively, both the factor λ and DI decrease. At the same time, the structures simplified formula under axial compression is presented.

Stress–strain relationship of concrete confined by rectangular steel tubes with binding bars

This paper presents a model for uniaxial stress–strain relationship of concrete confined by rectangular steel tubes with binding bars. The difference between concrete confinement effect provided by broad faces and that provided by narrow faces of steel tube is considered in the proposed model. Also, the binding bar arrangement in different directions is taken into account in the model. The failure criteria for concrete subjected to triaxial compression is applied to estimate the ultimate strength of concrete core. The parameters of the model are determined based on the experimental results and the calculation of complete load–strain relationship curves is conducted for axially loaded rectangular CFT specimens with binding bars using this uniaxial stress–strain relationship. The concrete core strength and stress–strain behavior of rectangular CFT columns with binding bars is found to exhibit good agreement with experimental results. In addition, the proposed model is also applicable to concrete confined by rectangular steel tubes without binding bars.

A New Method to Estimate Ductility of L-Shaped CFT Columns with Binding Bars under Axial Compression

Ductility of six L-shaped concrete-filled steel columns with binding bars and one without binding bars were discussed based on the experimental study. A new method based on material properties instead of experimental data was proposed to estimate the ductility of six L-shaped concrete-filled steel columns with binding bars and one without binding bars. Comparison between ductility coefficients based on experimental data and the calculated values by the proposed method shows good agreement.