Column Members Research Articles

Buckling capacity of cold-formed steel structure column member with perforation section in affordable house framing system

PurposeThe purpose of this study is to know the buckling capacity for cold-formed C-column with perforation. Cold-formed C-column have been used in interior wall construction. The concept of web perforation in the column has been introduced to the construction sector to overcome the issue of material cost.Design/methodology/approachInitially, the determination of the suitable spacing for the space column for the affordable house is investigated. Analysis house frame has been done in STAAD Pro. (Staad Pro, 2003) software using cold-formed C-column without perforation. Perforation with circular shape has been used in this study with the size of 0.4, 0.6 and 0.8 D (D = 180 mm). Perforation spacing is 150, 250 and 350 mm are adopted.FindingsFor the specimen with 0.4 D perforation and the edge distance is 539 mm have the highest buckling capacity (26.59 kN). Reduction of buckling capacity is 5.31% from cold-formed C-column without perforation and reduction of the volume is −2.16%. For the same case with 0.8 D perforation, the buckling capacity reduces with 22.52% and volume is −6.85%.Originality/valueThe conclusion of this analysis, C-column without perforation have higher buckling capacity compare to C-column with perforations.

Performance improvement of rigid connection by reduced web section with cellular beam and column subjected to cyclic loading

The behaviour under cyclic loading of a cellular beam and cellular column on the beam-to-column rigid connection was studied. The main focus was at the connection when openings were implemented to the beam and column members. The study aims to determine the increase of the yield and ultimate strength of the whole rigid connection, the ductility of connection and the energy dissipation in each loading cycle. Finite element analysis with both nonlinear material and geometry was conducted. The results indicated that the implementation of a cellular member could increase the yield strength of the overall rigid connection by 28.81%, the ultimate load by 30.93% and the stiffness by 36.21% compared to the original.

Quantification of the reduction factors of seismic capacity for damaged RC column members using the experiment database

AbstractStatic‐cyclic loading is used to identify the reduction factors of seismic capacity of damaged reinforced concrete (RC) column members. The reduction factors of seismic capacity that are obtained from specimens damaged under static‐cyclic loading differ from those obtained in dynamic testing, and this difference is investigated in this work. The experimental results obtained in this work, previously obtained results, and the “Pacific Earthquake Engineering Research Center Structural Performance Database (PEER)” are used to obtain reduction factors of strength, stiffness, and energy dissipation. From the damage levels of column members after an earthquake, corresponding reduction factors can be determined and used in the seismic assessment of an RC building.

Effect of steel braces buckling on inelastic torsion and design prevention of steel braced concrete frame structure

The influence of steel brace buckling on inelastic torsion of steel braced concrete frame structure is studied. On the background of a project, the shaking table test results of two structural models with ordinary steel brace (BRC) and buckling-restrained brace (BRB) are compared, and the inelastic torsion and sudden increase caused by steel brace buckling is confirmed. Finite element analysis models with BRC, BRB and floor load eccentricity are established, in which the restoring force model of steel brace considered the asymmetry of tensile and compressive bearing capacity, and the concrete beam and column members considered M3 and PMM hinge respectively to study the process and characteristics of the influence of BRC buckling on the nonlinear torsion of the structure. The mechanism of inelastic torsion of steel braced concrete frame structure (F-BRC) induced by BRC buckling is studied, and the principle that the dynamic BRC buckling makes the structure acquire inertial force as well as inertial torsion moment is found out. It is more reasonable to explain the inelastic torsional process and the mechanical characteristics of the structure by this principle than by the theory of strength eccentricity and stiffness eccentricity. Finally, based on the principle, six numerical examples with different brace schemes under the excitation of eight earthquake waves are calculated, and the changing rules of the torsional moment are studied. Some design limitation suggestions are put forward.

Torsional Stability Assessment of Columns Using Photometry and FEM

This paper presents a numerical analysis of the load-carrying capacity of steel open-section columns of a coal power plant structure. The structure was subjected to soil subsidence, which led to considerable structural deformations and damages. As a result, additional stresses appeared in the structure, and the static scheme of the structure was changed. To assess the influence of structural changes on the safety of the structure, a detailed investigation was necessary. Laser scanning was used to collect information concerning the geometry of structural elements. Results of the scanning were implemented in a numerical model of the structure. A complex finite element method (FEM) shell model of the column in ABAQUS software was developed. Torsional buckling stability analysis of column members was carried out. Different boundary conditions depending on the type of column connections to other elements were considered. Torsional deformations were treated as imperfections. Analysis showed that the connections of bracing elements, e.g., beams in multilevel frame, directly affected the collapse mechanism and load-bearing capacity of the investigated element. Finally, the paper showed that an appropriate change in the connections between the analyzed column and multilevel frame beams prevents the column from twisting, thereby increasing the critical force and load-bearing capacity of the analyzed industrial structure.

Reducing the wind pressure at the leading edge of a noise barrier

A method to reduce the wind pressure at the leading edge of a noise barrier was investigated by gradually lowering the height of a member added to the end of the noise barrier. The shape of the lowered height of the added member was defined by its length and slope, and the optimal variable was determined in wind tunnel testing via the boundary-layer wind profile. The goal of the optimal shape was to reduce the wind pressure at the leading edge of the noise barrier to the level suggested in the Eurocode and to maintain the base-bending moment of the added member at the same level as the noise-barrier section. Using parametric wind tunnel investigation, an added member with a slope of 1:2 that protruded 1.2 times the height of the noise barrier was proposed. This added member is expected to simplify, or at least minimize, the types of column members required to equidistantly support both added members and noise barriers, which should thereby improve the safety and construction convenience of noise-barrier structures.

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

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.

Application of Post-Embedded Piezoceramic Sensors for Force Detection on RC Columns under Seismic Loading

To quantify damage to reinforced concrete (RC) column members after an earthquake, an engineer needs to know the maximum applied force that was generated by the earthquake. Therefore, in this work, piezoceramic transducers were used to detect the applied force on an RC column member under dynamic loading. To investigate the use of post-embedded piezoceramic sensors in detecting the force that is applied to RC columns, eight full-size RC column specimens with various failure modes were tested under specific earthquake loadings. Post-embedded piezoceramic sensors were installed at a range of depths (70–80 mm) beneath the surface of a column specimen to examine the relationship between the signals that were obtained from them and the force applied by the dynamic actuator. The signals that were generated by the post-embedded piezoceramic sensors, which correlate with the applied force, are presented. These results indicate that the post-embedded piezoceramic sensors have great potential as tools for measuring the maximum applied force on an RC column in an earthquake. In other words, signals that are obtained from post-embedded piezoceramic sensors on an RC column in an earthquake can be used to determine the applied force and corresponding damage or residual seismic capacity.

Quantitative collision risk assessment of a fixed-type offshore platform with an offshore supply vessel

Offshore installations are designed to withstand against potential collisions from offshore supply vessels (OSV). Quantitative risk assessment (QRA) provides an overall picture of expected collision frequencies and consequences for the design life of a platform and subsequently estimates the damage repair cost. However, the main challenge of the QRA study is how well various uncertainties are implemented into the model. This study aimed to introduce and demonstrate an advanced and efficient QRA model for the collision between an OSV and a jacket type offshore platform. A set of fifty collision scenarios were selected using probabilistic sampling techniques, and vessel motion analyses were performed to determine collision load characteristics. Extensive nonlinear structural crashworthiness analyses were conducted using advanced computational modelling techniques, and the repair cost of the damaged brace and column members were calculated. Probability exceedance diagrams were established for different consequence parameters, and asset risks were calculated. A comparison study of the design values of damage parameters and repair costs were carried out in association with the NORSOK and HSE risk acceptance criteria. A sensitivity study was carried out to study the effects of various collision load parameters on the structural consequences. The methods and insights developed in this study could be applied to both new and existing offshore platforms and practically useful for the platform owners to aid in their decision-making process towards the risk-based safety analysis of offshore platforms.

Shear force‐deformation relationship of concrete‐filled square steel tube beam‐columns under monotonic lateral loading

AbstractThis paper proposes a simplified multi‐linear model of a shear force‐deformation relationship for concrete‐filled square steel tube short to slender beam‐columns. To evaluate the behavior of short to slender beam‐columns with a single model, the column member is divided into elasto‐plastic part and an elastic part. For the elasto‐plastic part, the deformation at each point is calculated based on the bending moment‐curvature relation model proposed by the author and by employing a newly proposed evaluation formula for curvature magnification. Predictions from the model are found to agree approximately with the experimental results up to large deformations.

A Modular Approach for Steel Reinforcing of 3D Printed Concrete—Preliminary Study

3D concrete printing technology has considerably progressed in terms of material proportioning and properties; however, it still suffers from the difficulty of incorporating steel reinforcement for structural applications. This paper aims at developing a modular approach capable of manufacturing 3D printed beam and column members reinforced with conventional steel bars. The cubic-shaped printed modules had 240 mm sides, possessing four holes on the corners for subsequent insertion of flexural steel and grouting operations. The transverse steel (i.e., stirrups) was manually incorporated during the printing process. The reinforced 3D printed beams were built by joining the various modules using high-strength epoxy resins. Test results showed that the compressive and flexural strengths of plain (i.e., unreinforced) 3D printed specimens are higher than traditionally cast-in-place (CIP) ones, which was mostly attributed to the injected high-strength grout that densifies the matrix and hinders the ease of crack propagation during loading. The flexural moment capacity of 3D reinforced printed beams were fairly close to the ACI 318-19 code provisions; however, about 22% lower than companion CIP members. The reduction in peak loads was attributed to the modular approach used to construct the 3D members, which might alter the fundamentals and concepts of reinforced concrete design, including the transfer and redistribution of stresses at ultimate loading conditions.

Numerical Evaluation of the Steel Plate Energy Absorption Device (SPEAD) for Seismic Strengthening of RC Frame Structures

In this paper, a new strengthening technique is proposed: the Steel Plate Energy Absorption Device (SPEAD) system, which is intended to increase the flexural strength of beam and column members in RC frame structures. In this way, while permitting calibration of the strength increase in the beam to comply with the strength hierarchy criteria needed for a proper seismic behaviour it can provide additional energy absorption. A numerical evaluation of the SPEAD system is carried out by means of a refined 3D model built with an advanced nonlinear finite element program. The SPEAD system has been virtually applied (through finite element analyses) to an RC external beam–column joint, representative of typical existing RC buildings, and the numerical results are compared to those of a specimen that was not upgraded and subjected to the same experimental tests. The SPEAD upgraded model provided a strength increment of about 50% with also a strong reduction of bond-slip effects in the joint panel region. This latter, in turn, provided a beneficial increase of ductility. Based on the positive results from numerical simulations, a design method is also provided.

A Review on Base Shear Reduction by using same Grade of Concrete by Optimizing Size of Column Member

India is the fastest growing economy in the world and infrastructure plays a very important role in it. The Construction of high rise buildings in India is growing day by day. Therefore new ideas and venture are needed to make the building safe, economic and durable. The base shear reduction by using Optimum Size of column in Top Floors in Multistoried Building under seismic loading is the one of them. It reduces the size of column at the top levels of the building to reduce its self-weight.

The Effects of Loading Conditions on the Behaviour of Fixed-Ended Plain Channel Columns.

The compressive behaviour of column members can be considerably affected by local buckling, material yielding and local end conditions. In this paper, the effects of the loading conditions at the ends of plain channel section columns subjected to uniformly compressed loading, and fixed conditions at the column ends with respect to global rotations, was examined. Finite element simulation was employed to look at the post-buckled response of thin-walled, plain channel section columns that covered the complete loading history of the compression columns from the onset of elastic local buckling through the nonlinear elastic and elastoplastic post-buckling phases of behaviour to final collapse and unloading. Two types of loading conditions were considered: the first was one that has been used practically in tests whereby one end is loaded with a moving top platen while the other end is fixed at the lower platen, but, for the second loading condition, both ends were loaded with equally moving top and lower platens. These two conditions were shown to lead to quite different characteristic interactive responses of the columns due to mode jumping in the buckling mode for the locally rotationally constrained case.

A Macro-method for Including Bond–Slip Flexibility Within Fibre Element Formulation for Simulating Hysteretic Behaviour of RC Beam–Column Members

Fibre beam–column elements are frequently used in the nonlinear analysis of reinforced concrete (RC) frames. The “plane-sections remain plane” assumption in the fibre element formulation results in perfect–bond between rebar and surrounding concrete matrix, which neglects bond–slip added flexibility effects. This drawback affects the lateral stiffness, deformation, energy dissipation, yield displacement, and ductility of an RC member and consequently the RC structure. In this paper, a simple and effective method is presented for incorporating bond–slip flexibility within the plastic hinge of an RC member into fibre elements available in commercially developed computer programs. The developed macro-method modifies rebar elastic modulus using a rebar elastic modulus modification coefficient determined through a simplified and systematic formulation. Furthermore, in this study main design parameters contributing to rebar modulus modifications are determined. Although the developed formulation is simple, it has adequate accuracy and robustness which are verified using a large number of experimental test results.

Torsional Buckling of Thin-Walled Columns with Transverse Stiffeners: Analytical Studies

In this paper the pure torsional buckling of thin-walled column members is investigated, with a special focus on the effect of transverse plate elements, such as end-plates or transverse stiffeners. The linear buckling problem is aimed to solve analytically, therefore the necessary (differential) equations are first established. For some simple problems, namely doubly-symmetric I-sections with pinned-pinned or clamped-clamped supports and with rectangular stiffeners or end-plates, closed formulae are derived to calculate the critical force. It is shown that the transverse elements have two effects: the direct effect is due to the deformation of the transverse elements, while the indirect effect is that the transverse elements modify the longitudinal distribution of the member’s displacements. It is also shown how the stiffener-to-member connection influences the results. The analytical solutions are discussed by several numerical examples: the results from the derived formulae are compared to results from shell finite element buckling analyses.

Rotational behavior of bolted glulam beam-to-column connections with knee brace

This paper investigates the rotational behavior of bolted glulam beam-to-column connections reinforced by knee brace. Due to the low rotational stiffness of conventional glulam beam-to-column connections (i.e., bolted connection with slotted-in steel plate), diagonal braces are usually installed to increase the lateral load resisting capacity of the structure. However, the architectural space will be heavily impacted by such installation. Column and beam members combined with knee braces would be a compromise between the enhancement of connection mechanical performance and the flexibility of architectural layout. Sixteen specimens with different knee brace configurations were designed for a series of monotonic and reserved cyclic loading tests. The failure modes, moment-resisting capacity, stiffness degradation, and hysteretic moment-rotation responses of the specimens were tested and evaluated. Results showed that the installation of knee brace led to a more ductile failure mode. For the investigated connections with knee brace, the initial stiffness was 5.98 times that of the corresponding bolted connection without knee brace, and the moment-resisting capacity was 6.80 times that of the corresponding bolted connection without knee brace. Moreover, the influence of different knee brace configurations (e.g., section modulus of the knee brace, installation angle, installation end distance, etc.) on the rotational behavior of the connections were discussed. An optimized knee brace configuration was proposed to improve the rotational behavior of the connections and to decrease the damage accumulation in the glulam beam and column members. Nonlinear numerical models, including a detailed three-dimensional model and a simplified model, were further developed to comprehend the mechanical performance of such connections. The presented experimental and analytical results can be used as reference for the development of design guidelines for the glulam bolted connection with knee brace in practical projects.

Effect of fully restrained beam-to-column connection on the progressive collapse strength of steel moment frames

The beam-to-column connection has been identified as a key element for steel frame structures to maintain the structural integrity during progressive collapse phenomenon. In the current study, in order to assess the effects of beam-to-column connection type on the progressive collapse strength of steel moment frames, the progressive collapse behavior of a steel intermediate moment frame structure was evaluated with 10 different types of fully restrained connections. The progressive collapse strength of these buildings against sudden removal of a column was separately studied using nonlinear static alternate path method presented in Unified Facility Criteria progressive collapse guideline. To consider the nonlinear effects in the structural modeling, plastic hinges for beam and column members and connections were defined and modeled according to the ASCE 41 standard. The results of the progressive collapse analyses indicated that if the plastic hinges of connections are separately defined in addition to the plastic hinges of beams and columns, the structure will have lower progressive collapse strength, and the calculated dynamic increase factor will grow. Among the studied types of connections, the free flange connection had the best performance and the highest strength against progressive collapse.

Numerical investigation on the response of circular double-skin concrete-filled steel tubular slender columns subjected to biaxial bending

Recently, Concrete-filled double skin steel tubular (CFDST) columns have proven an exceptional structural resistance in terms of strength, stiffness, and ductility. However, the resistance of these column members can be severely affected by the type of loading in which bending stresses increase in direct proportion with axial load and eccentricity value. This paper presents a non-linear finite element based modeling approach that studies the behavior of slender CFDST columns under biaxial loading. Finite element models were calibrated based on the outcomes of experimental work done by other researchers. Results from simulations of slender CFDST columns under axial loading eccentric in one direction showed good agreement with the experimental response. The calibrated models are expanded to a total of thirty models that studies the behavior of slender CFDST columns under combined compression and biaxial bending. The influences of parameters that are usually found in practice are taken into consideration in this paper, namely, eccentricity-to-diameter (e/D) ratios, slenderness ratios, diameter-to-thickness (D/t) ratios, and steel contribution ratios. Finally, an analytical study based on current code provisions is conducted. It is concluded that South African national standards (2011) provided the most accurate results contrasted with the Eurocode 4 (2004) and American Institute of Steel Construction (2016) that are found to be conservative. Accordingly, correction factors are proposed to the current design guidelines to provide more satisfactory results.

Behavior of hollow circular steel columns in compression retrofitted with aramid fibre reinforced polymer composites

Steel structure is a magnificent pliable material which, in conjunction with the help of both stability and strength, can accomplish both compressive and tensile strength in a manic directing manner. But steel and concrete structures, as of various structural cataclysms and natural cataclysms, slacken their forte in the age which is a recent tricky of noteworthy partisan and societal applicability. The restructuring of structures from these difficulties and subtle earthquakes has now become a vital construction work, both for concrete and steel structures. The results of past experimental studies have shown that structural promotion using fiber strengthened polymers have a sturdily positive effect. The technology provided by Fibre Reinforced Polymer (FRP) sheet has developed a new trend, given the many disadvantages in conventional methods to retrofit structures. This article is an experimental study on Aramid Fiber Reinforced Polymers (AFRP) and its effect on strengthening of Hollow Circular Steel (HCS) column members. In this experimental study, a total of 15 HCS samples have been troupe and tested, including both control and fortified specimens. The results articulated from the number of experiments show that, after application of AFRP and also improved interment of AFRP fabrics, the carriage capacity of the HCS specimens increased. The results were compared to the test specimens and subsequently the properties of the members were studied with the hunt down of load-deflection curves and axial elastic curve after the experimental assessments.