Low-rise Steel Frames Research Articles

Numerical Investigation on the Efficiency of Self-Centering Two-Yield Buckling Restrained Brace on Low-Rise Steel Frames

Numerical Investigation on the Efficiency of Self-Centering Two-Yield Buckling Restrained Brace on Low-Rise Steel Frames

Damage distribution mechanism of common low-rise steel frame structures

In order to research the damage distribution mechanism of common low-rise steel frame structures under dynamic action, this paper took the column-to-beam strength ratio αi and column base form as the main parameters to research the seismic performance of common low-rise steel frames. To achieve this goal, 24 models of common low-rise steel frame structures were designed and analyzed by elasto-plastic time history analysis method; and the predominant periods of seismic waves are similar to the fundamental periods of these models. This paper focuses on the demand performance of each model such as the distribution of maximum inter-story drift ratio (MIDR), the deformation concentration rate of the first floor dR1, the ductility ratio μ and cumulative plastic ductility ratio η of the beams and columns; and clarifies the relationship between the damage mechanism of common low-rise steel frame structures and column-beam strength ratio αi and column base form in the first place. After that, to investigate the effect of each parameter on the structural energy dissipation, the plastic deformation energy distribution of each model was also studied in this paper. Finally, the mathematical equations of the seismic input energy and plastic deformation energy were studied, which can apply to common low-rise steel frame structures in the resonant state. It can provide a reference for engineers to choose the column-to-beam strength ratio αi and the column base form in the design of low-rise steel frame structures.

Quantification and parametric investigation for plan asymmetric low-rise steel frame structure considering soil-structure interaction under vertical ground motion

Quantification and parametric investigation for plan asymmetric low-rise steel frame structure considering soil-structure interaction under vertical ground motion

Experimental Study of the Seismic Behavior of a Prefabricated Low-Rise Steel Frame Structure with Hinged Joints

This paper investigated the seismic behavior of a prefabricated steel braced frame structure with hinged joints. Six steel frame specimens with different enclosure walls were tested under pseudo-static loading. The results indicated that the vertical load of the hinged braced frame system was mainly resisted by the beam and column members, and the lateral stiffness was completely provided by the bracing members. The final failure mode of all specimens was the failure of the bracings, while the beam-column members and the joints remained largely intact. The rigidly braced specimen was mainly damaged by buckling, yielding, and tearing, and the flexibly braced specimen was mostly damaged by buckling, yielding, and node failure. The energy dissipation of the specimens primarily depended on lateral force-resistant components such as braces and enclosure walls. Different building envelopes exert significant effects on the lateral stiffness and energy dissipation capacity of the structure. The ductility coefficient of all specimens ranged between 1.4 and 1.9, which indicates that the structural system mainly relies on lateral stiffness and elastic deformation to resist earthquakes, rather than structural ductility. The proposed prefabricated steel frame system with hinged connections has wide prospects of application in economically underdeveloped areas because of its convenience in transportation and installation.

A Comparative Study on Performance of Conventional and Pre-Engineered Steel Frames Subjected to Crane Load

Abstract: Conventional steel frames are low rise steel frames with roofing systems of truss and roof coverings. Standard hot rolled sections are used for truss elements which are usually much heavier than what is actually required as per the design. Pre– Engineered steel frames are the steel frames in which excess steel is tapered as per the bending moment requirements. In present study, conventional (pratt type) steel roof truss and pre-engineered (portal type) steel roof frame with crane load is considered for an industrial warehouse construction located in Davangere city. 2D Modelling of both conventional and pre-engineered steel frame with crane load is done using STAAD Pro. software. Both the steel frames are subjected to different combinations of Dead load (DL), Live load(LL), Crane Load(CL) and Wind load(WL) as per IS 800 (2007) codal provisions. For the factored bending moments and shear force, referring IS 800 (2007) codal provisions, crane gantry girder is designed as a laterally unsupported member having a combination of I and channel sections. The members of both conventional and pre-engineered steel frames with crane load are designed for the worst load combination as per IS 800(2007) codal provisions. It is concluded that about 25% reduction in quantity of steel can be achieved by choosing pre-engineered steel frame than the conventional steel frame.

Behavior of exposed column-base connections with four internal anchor bolts under seismic loading

Laboratory experiments were conducted to define the response to earthquake loading of the exposed column-base connections common in low-rise steel frame structures. Six full-scale column-base connections with four internal anchor bolts were prepared and tested to failure under major- and minor-axis cyclic loading. The parameters varied were the size and thickness of the base plate and the diameter of the anchor bolts. The data were used to calibrate a finite element simulation, and that was used to predict the influence of other design parameters on the initial rotational stiffness of a connection. Linear regression was used to model the response surface of the initial rotational stiffness and the bending capacity of the connections under minor-axis loading. A three-parameter power function model was derived which acceptably predicted the experimental results.

Numerical Study on Dynamic Behavior of Glass Screen Based on Out-of-Plane of Low-rise Steel Frame Building Based on Seismic Observation Records

Numerical Study on Dynamic Behavior of Glass Screen Based on Out-of-Plane of Low-rise Steel Frame Building Based on Seismic Observation Records

Dynamic performance of low-rise steel frame with exposed steel column base

The influence of changes in strength of exposed steel column bases (ESCBs) on the dynamic response of low-rise steel frames was studied by building on the theoretical sliding hysteresis curve model of ESCBs on the basis of a previous experimental study. The first-floor shear–weight ratio (CB = 0·30 and 0·35) and frame shape were taken into account in designing 16 strong-column/weak-beam regular low-rise steel frame models with the ratio of the strength of column bases to the strength of the first-floor column as the main study parameter. The results showed that when the strength coefficient of the steel column base was lower than 0·7, the model deformed at the first floor and plastic energy was concentrated if the first-floor shear–weight ratio was 0·30, while the first-floor deformation and plastic energy concentration of the model eased if the first-floor shear–weight ratio was 0·35. In addition, the lower the strength coefficient of the steel column base, the more obvious was the easing effect. The energy absorption of the column bases was not significant, but the column bases were able to transfer input seismic energy to other components during the plastic sliding process. The dynamic response hysteresis curves of the column bases matched the theoretical model well.

On the seismic response and damping capacity of low-rise plane steel frames with seesaw system

This paper summarizes estimated seismic response results from nonlinear inelastic seismic analyses of low-rise plane steel frames equipped with a seesaw system in which linear viscous dampers have been applied. More specifically, considering for each frame three different configurations of the seesaw system and two different orientations of columns, seismic response results involving height wise distributions for peak interstorey drift ratios (IDR), peak residual interstorey drift ratios (RIDR) and peak floor accelerations (PFA) have been obtained. Moreover, peak seismic demands in columns and in the steel plates of the seesaw are found. Results in terms of modal damping ratios are also provided for all frames and seesaw configurations examined. From the results presented, it can be concluded that the seesaw system provides a very attractive solution for typical low-rise steel frames offering significant damping capacity and reduction of their seismic response.

A Simplified Approach for Evaluating Second-Order Effects in Low-Rise Steel Framed Buildings

Consideration of second-order effects is one of the most involved tasks in the analysis and design of steel framed buildings. More specifically, the evaluation of amplified moments due to frame level second-order effects is a very time consuming task because, depending on the method used, it may require an additional first order analysis or the introduction of additional notional loads for each considered load case. Although the use of such methods may not present a problem when the design process is fully automated, hand calculations can be quite complicated for checking the results of a computer generated design or for designing a small structure in which second-order effects may not even be significant enough to affect the selection of member sizes. This paper presents a simplified approach for the incorporation of second-order effects in the design of low-rise steel framed structures. The development of this approach involved the design and analysis of a number of systems with various numbers of bays, floors and beam-span to floor-height ratios and included a thorough investigation of the effect of moment amplification on final member sizes. To facilitate this task, a spreadsheet application was developed to automate the design of a typical low-rise steel frame under given loading conditions. A parametric study was then performed to understand the effect of the various design parameters on member-level and frame-level second-order forces and moments. This led to the development of the simplified design approach proposed in this paper.

露出型柱脚を有する低層剛接骨組の地震時挙動

Column bases are most important parts in strength and deformation capacity in the estimate of seismic resistance of steel framed structures. A lot of research works has been made, however, the relationship between the structural behavior and the behavior of column bases has not been made clear yet. In this paper, the analytical model of fish-bone of frame is applied and the experimental results of column bases is introduced. Five-storied weak-beam type frames are taken. The bottom of columns is equipped with actual column bases. Damage distribution and deformation of the column bases are analyzed in terms of the intensity of seismic input. As a references, two type of idealized fundamental frames are introduced. Based on the result of analysis, the design method of column bases for low-rise steel frames is summarized.

Experimental study of beam-column connections with web opening in a low-rise steel frame

Steel frame structures have been widely used in multi-storey and high-rise buildings and the connections in these structures are critical. In the Northridge and Kobe Earthquake, beam-column connections suffered damage due to brittle fracture. According to seismic design codes, ductility of the beam to column connection is also necessary. A study on the behavior of a beam to column connection with the aim of improving ductility as well as preventing brittle failure was carried out. In order to control the position of a plastic hinge on the beam, a connection with a hole in the beam web was developed. Five specimens with different parameters under cyclic load were assessed. The results are presented in terms of the stress distribution of the beam, hysteretic behavior, and ultimate capacity. Furthermore, the finite element method was also used to analyze the model, and the results were compared with those obtained from the experiment. It is shown from the analysis and experimental results that this type of connection is effective in terms of improving ductility for a beam to column connection in low-rise buildings.

Seismic design of low-rise steel frames with buckling-restrained braces

In this study, a direct displacement design procedure for steel frames with buckling-restrained braces (BRBs) is presented. The proposed structure system is composed of a hinge-connected main structure, which is designed to remain elastic under seismic load, and BRBs resisting all lateral loads. At seismic event, the BRBs dissipate dynamic energy through stable hysteretic behavior. A displacement-based seismic design procedure is applied to model structures to check the applicability of the design procedure. Two artificial earthquake records are generated from a design spectrum, and the response spectra constructed based on the earthquake records are utilized in the design process. Time-history analyses are carried out to confirm that the maximum displacements coincide with the target displacements. The results show that the seismic performance of the 3- and 5-story model structures designed in accordance with the proposed method coincide well with the given design objectives.

A neural dynamics model for structural optimization—Application to plastic design of structures

In a companion paper we presented a neural dynamics model for optimization of structures by integrating penalty function method, Lyapunov stability theorem, Kuhn-Tucker condition, and the neural dynamics concept. In this paper, we apply the model to optimum plastic design of low-rise steel frames. The objective and constraint functions are scaled to improve the efficiency and numerical conditioning of the algorithm. As demonstrated in the convergence histories for the four examples presented, the neural dynamics model yields stable results no matter how the starting point is selected. Since the neural dynamics model lends itself to concurrent processing effectively, development of a concurrent neural dynamics model for optimization of large structures appears a very promising approach, which is currently under investigation by the authors.

Response of Low‐Rise Steel Frames with Fabrication Errors

An evaluation of the errors that usually occur during the fabrication and erection of bolted connections of steel frames is presented. Specifically, the significance of fabrication errors on the serviceability of low-rise steel frames under wind and low-level seismic action is studied. The moment rotation relationship of a partially restrained (PR) top and seat angle connection is developed based on behavior models that include the effects of each fabrication error. Nonlinear analyses of a low-rise steel frame under lateral wind action and low-level seismic load are performed. The comparative seismic responses of frames with and without fabrication errors are presented in the form of response amplification factors, in which the maximum interstory drift of the frame is plotted with respect to the fundamental frequency. The frame response under wind effect is compared to frames with no fabrication efforts.

中低層鋼骨組の耐震性に与える柱-はり接合部のせん断補強の効果について : その 2 パネルゾーンせん断強度が異なる骨組の動的弾塑性応答性状

中低層鋼骨組の耐震性に与える柱-はり接合部のせん断補強の効果について : その 2 パネルゾーンせん断強度が異なる骨組の動的弾塑性応答性状

中低層鋼骨組の耐震性に与える柱-はり接合部のせん断補強の効果について : その 1 崩壊荷重係数と等価吸収エネルギー

Energy absorption capacity of frames under severe earthquakes is required for a current design of low-rise steel frames. In this paper, the superior elasto-plastic behavior of beam-to-column connections without shear stiffening is employed for the frame energy absorption to avoid (1) damage concentration in a story of the frame during severe earthquakes, (2) member instability caused by lateral or local buckling which is apt to develop in plastic range. The effect of plastic deformation of the connections in an aseismic design of the frame is theoretically investigated herein. Some results are : (1) The energy absorption of a frame with no-shear stiffening connections corresponds to one with shear stiffening connections by giving only 1.3〜1.5 times story displacement. (2) At that story displacement, the plastic deformation of the connections without shear stiffening remains within stable region in the restoring force characteristics. (3) The aseismic design of frames depended on the energy absorption capacity of connections, that is, panelcollapse design of frames with elastic members is possible.