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A new type of Reduced Beam Section (RBS) connection, called \Tubular Web RBS (TW-RBS)", is proposed in this research. TW-RBS is made by replacing a part of web with a tube at the expected location of the beam plastic hinge. In addition to an analytical study, the proposed section is numerically studied under cyclic load using ABAQUS finiteelement s...
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In this study to evaluate the effect of high-strength steel and energy-absorbing steel in fully restrained moment frames (FR), a numerical investigation of column-tree moment frame with three types of steel as ST37, ST19 and ST52 is undertaken. The innovation of this study includes the usage of high-strength steel in rigid moment frame connections,...
Citations
... Mansouri et al. (Mansouri et al., 2021) used corrugated web, Mirghaderi et al. (Mirghaderi et al., 2010) used vertical rectangular pipes, and circular welded pipes. Web bracing Roudsari et al. (Roudsari et al., 2016), replaceable channel assembly Zahrai et al. (Zahrai et al., 2017). Bai et al. (Bai et al., 2021) proposed unique strategies and components to defend the web in the area of the decreased zone. ...
Steel beam column connection suffers damage during the earthquakes and main cause of failure of structural systems in steel buildings. The maintenance of the building after the earthquake is also a key issue. Here the innovative fuse connection with reduced web opening including stiffening plate attachment has been proposed. The fuse is the element which will get damage first during the earthquake and this can be replaced also. Innovative opening shapes with square, circular, triangle, elliptic, double triangle and double elliptic has been suggested. Here the triangle and square connection has been provided with filet edges to reduce the stress concentration effects. The stiffening plate will also impart the strengthening effect on the connection. The cyclic loading has been applied to numerical model to perform the comparative study. Energy dissipation, PEEQ, Von misses stress distribution, rupture index, strength degradation and lateral deformation of the connection have been studied. From the overall analysis the double elliptic shape reduced web fuse connection has shown the best behaviour among all.
... The reduction of beam flange by more than 40% resulted from plane rotation like web buckling and flange buckling due to torsion, observed by [3]. However, novel techniques and components were also proposed to protect the web like corrugated web [4], application of vertical rectangular [5], circular welded pipes [6], web bracing [7], replaceable channel assembly [8], etc., in the vicinity of the reduced zone. ...
This work follows the latest development trend in resilient structures by arresting inelastic damage in a small replaceable link at a predetermined location. Toward this, here innovative beam fuse has been proposed with circular, triangle, square, and elliptic openings. These openings are also provided with a stiffening plate of 5 mm thickness to reduce the stress concentration effects inside the opening edge. Comparative analysis has been carried out for four beam-column sub-assemblages in ABAQUS FEM software. In this modeling, the bolted end plate has been omitted as the focus is only on the connection's pure fuse behavior. SAC loading protocol has been adopted to evaluate the cyclic behavior of the connections. Strength degradation, ductility, and energy dissipation have been studied. All the fuse connections show excellent ductility under the cyclic loading. For all the fuses based on rupture, index cracking may occur between the web plate and the stiffening plate of the fuse. Here, fuse with a circular opening shows the highest amount of energy dissipation.KeywordsReplaceable fuseEnergy dissipation capacityStiffening plateResilient structuresFEMcyclic
... The reduction of beam flange by more than 40% resulted from plane rotation-like web buckling and flange buckling due to torsion, observed by (Sophianopoulos & Deri, 2017). However, novel techniques and components were also proposed to protect the web-like corrugated web (Mansouri et al., 2021), application of vertical rectangular (Mirghaderi et al., 2010), circular welded pipes (Zahrai et al., 2017), web bracing (Roudsari et al., 2016), replaceable channel assembly (Bai et al., 2021), etc., in the vicinity of the reduced zone. ...
This work follows the latest development trend in resilient structures by arresting inelastic damage in a small replaceable link at a predetermined location. Toward this, here innovative beam fuse has been proposed with dog bone shape of parabolic, circular, smooth surface, triangle, and sharp type. These fuses are also provided with a flange of 8 mm thickness and web plate of 4 mm thickness. Comparative analysis has been carried out for five beam–column sub-assemblages in ABAQUS FEM software. In this modeling, the bolted end plate has been omitted as the focus is only on the connection’s pure fuse behavior. SAC loading protocol has been adopted to evaluate the cyclic behavior of the connections. Strength degradation, ductility, and energy dissipation have been studied. All the fuse connections show excellent ductility under the cyclic loading. For all the fuses based on rupture index, cracking may occur between the web plate and the flange plate of the fuse. Here fuse with smooth dog bone shape shows the highest amount of energy dissipation.
... In these connections, a relatively large void is required to reduce the stresses over the beam-to-column CJP welding region, yet the large void causes the local buckling instability at the cutting edges of the beam web (Boushehri et al. 2019;Momenzadeh et al. 2017). In order to overcome this instability, some researchers have proposed and investigated the accordion/tubular-web RWS connections in which the flat web is replaced by a corrugated-web (Zahrai et al. 2017;Mirghaderi et al. 2010;Nadi et al. 2020;Imanpour et al. 2019). Nadi et al. (2020) showed that the Holed Tubular-Web (HTW), which is a kind of accordion-web, decreases the fatigue phenomenon caused by the stress concentration in the connection of the tube and beam. ...
... Nadi et al. (2020) showed that the Holed Tubular-Web (HTW), which is a kind of accordion-web, decreases the fatigue phenomenon caused by the stress concentration in the connection of the tube and beam. Besides, (Zahrai et al. 2017) demonstrated that the tubular-web RWS provides a better condition than the accordion-web RWS in terms of lateral-torsional buckling stability of the beam and low-cycle fatigue. In any case, although this type of connection behaves well in terms of plastic hinge formation in the reduced region, its construction is relatively difficult, costly, and time-consuming. ...
... According to Refs. (Zahrai et al. 2017;Hedayat and Celikag 2009), the plastic hinge should be formed at a distance approximately equal to the beam depth from the column face. ...
Extensive research has been carried out on steel moment frames to improve the cyclic performance of seismic resisting connections with Reduced Beam Section (RBS). The lateral-torsional buckling and reducing of the flexural resistance of the beam are the disadvantages of conventional RBS connections with radial cutting in the flange. Therefore, some researchers have suggested the reducing of the web in lieu of the flange as an effective strategy to prevent these phenomena. The present study aims to investigate the cyclic behavior of the reduced web section (RWS) connections with vertical-slits (VS) as a cost-effective alternative with multiple design parameters through an experimental and numerical study. Two full-scale specimens of the bolted end-plate VS-RWS connection were experimentally tested under the SAC cyclic loading to evaluate the performance of connections, and then in order to obtain proper ranges for the geometric design parameters, a parametric study was carried out using the verified numerical models. The parameters consist of the distance between the column face and the beginning of the reduced region, the length of the reduced region, as well as the depth and width of the vertical-slits. Based on the results, the appropriate ranges for the geometric parameters of VS-RWS have been recommended. In order to obtain the story drift of the frame caused by the VS-RWS beam flexural deformation using the conjugate beam method, the original VS-RWS was replaced with an equivalent constant-cut reduced beam section (CC-RBS). At last, a step-by-step design procedure for VS-RWS connections was provided according to AISC-358.
... In order to improve the performance of the AW-RBS connection in terms of low-cycle fatigue, researchers have developed another RBS connection called the Tubular Web RBS (TW-RBS) connection, in which the corrugated web is made by a pipe instead of a pair of L-sections [17][18][19][20]. The experiments have shown that this connection offers 9% story drift capacity in shallow beams and 6% story drift capacity in deep beam sections. ...
In a new type of Reduced Beam Section (RBS) connection, called the corrugated web RBS connection, the flat web of the beam in the section near the column face is replaced by corrugated plates so as to reduce the flexural strength of the beam and ensure hinge formation in this section. The use of the corrugated web in the reduced section zone increases the lateral-torsional stability of the beam and reduces its flange width-to-thickness ratio. This paper presents two new types of corrugated web RBS connection, called the curved cell web RBS (CW-RBS) and the hexagonal cell web RBS (HW-RBS). The design method is described and the seismic behavior of the connections is evaluated through finite element modeling and analysis. After validating the numerical model with the existing experimental data, a number of models created with the proposed details but for different beam and column sections and by considering three different depths for the corrugated cells are analyzed under cyclic loading. A number of control models including the radius cut RBS (RC-RBS), the accordion web RBS (AW-RBS), and the tubular web RBS (TW-RBS) connections are used for comparison. The results show that the proposed connections cause plastic hinges to emerge in the RBS zone, thereby preventing failure at the beam-column junction. The proposed connections offer stable hysteretic behavior with better ductility and lower strength degradation than the conventional RC-RBS connection. The proposed connections also develop significantly lower maximum equivalent plastic strains than both AW-RBS and TW-RBS, which can delay the failure of the beam in the RBS zone.
... In these connections, a relatively large void is required to reduce the stresses over the beam-to-column CJP welding region, yet the large void causes the local buckling instability at the cutting edges of the beam web [1,4]. In order to overcome this instability, some researchers have proposed and investigated the accordion/tubular-web RWS connections in which the flat web is replaced by a corrugated-web [6][7][8][9]. Nadi et al. [8] showed that the Holed Tubular-Web (HTW) which is a kind of accordion-web, decreases the fatigue phenomenon caused by the stress concentration in the connection of the tube and beam. Besides, Zahraei et al. [6] demonstrated that the tubular-web RWS provides a better condition than the accordion-web RWS in terms of lateral-torsional buckling stability of the beam and low-cycle fatigue. ...
... Nadi et al. [8] showed that the Holed Tubular-Web (HTW) which is a kind of accordion-web, decreases the fatigue phenomenon caused by the stress concentration in the connection of the tube and beam. Besides, Zahraei et al. [6] demonstrated that the tubular-web RWS provides a better condition than the accordion-web RWS in terms of lateral-torsional buckling stability of the beam and low-cycle fatigue. In any case, although this type of connection behaves well in terms of plastic hinge formation in the reduced region, its construction is relatively difficult, costly, and time-consuming. ...
Extensive research has been carried out on steel moment frames to improve the cyclic performance of seismic resisting connections with reduced beam section (RBS). The RBS connections are conventionally known by the radial reduction of the beam flange. Where the contribution of the beam flange to the flexural resistance is greater than that of the beam web, some researchers have proposed reduced web section (RWS) connections, instead. The present study dedicates to the RWS connections with vertical-slits (VS), as a cost-effective alternative with multiple design parameters. This paper aims to obtain proper ranges for the geometric design parameters of the VS-RWS connection. In this order, two full-scale specimens of the bolted end-plate VS-RWS connection were experimentally tested under the SAC cyclic loading to evaluate the performance of connections, and then a parametric study was carried out using the verified numerical models. The parameters consist of the distance between the column face and the beginning of the reduced region, the length of the reduced region, as well as the depth and width of the vertical-slits. Based on the results, certain recommendations for the ranges of the geometric parameters of VS-RWS have been suggested. In order to obtain the story drift of the frame caused by the VS-RWS beam flexural deformation using the conjugate beam method, the original VS-RWS was replaced with an equivalent constant-cut reduced beam section (CC-RBS). At last, a simple design procedure for VS-RWS connections was provided according to AISC-358.
... In these connections, a relatively large void is required to reduce the stresses over the beam-to-column CJP welding region, yet the large void causes the local buckling instability at the cutting edges of the beam web (Boushehri et al. 2019;Momenzadeh et al. 2017). In order to overcome this instability, some researchers have proposed and investigated the accordion/tubular-web RWS connections in which the flat web is replaced by a corrugated-web (Zahrai et al. 2017;Mirghaderi et al. 2010;Nadi et al. 2020;Imanpour et al. 2019). Nadi et al. (2020) showed that the Holed Tubular-Web (HTW), which is a kind of accordion-web, decreases the fatigue phenomenon caused by the stress concentration in the connection of the tube and beam. ...
... Nadi et al. (2020) showed that the Holed Tubular-Web (HTW), which is a kind of accordion-web, decreases the fatigue phenomenon caused by the stress concentration in the connection of the tube and beam. Besides, (Zahrai et al. 2017) demonstrated that the tubular-web RWS provides a better condition than the accordion-web RWS in terms of lateral-torsional buckling stability of the beam and low-cycle fatigue. In any case, although this type of connection behaves well in terms of plastic hinge formation in the reduced region, its construction is relatively difficult, costly, and time-consuming. ...
... According to Refs. (Zahrai et al. 2017;Hedayat and Celikag 2009), the plastic hinge should be formed at a distance approximately equal to the beam depth from the column face. ...
The reduced beam section (RBS) connections are widely used in construction buildings due to their desirable ductility and strength. The current reduced web section (RWS) connections are produced by a reduction in the beam web as circular or rectangular cuts or as horizontal slits. This article has proposed a new detail for the RWS bolted connection by creating vertical-slits in the beam web. The aim of this investigation is the evaluation of its cyclic performance in comparison with the conventional RBS connection. Two specimens, one with vertical-slits in the web (VS-RWS) and the other one with a radial-cut in the flange (RC-RBS), were experimentally tested and the results were compared. Moreover, numerical models were employed to evaluate the behavior of connections in detail. These two connections were able to move the plastic hinge region away from the column face, exhibit good hysteresis behavior, and satisfy the AISC requirements for special moment-resisting frames. The results also showed that the flexural capacity of the proposed VS-RWS connection is 10% higher than that of the conventional RC-RBS one, while their ductility and energy dissipation were almost the same. An important advantage of VS-RWS over RC-RBS is its ability to prevent the lateral-torsional instability. Besides, a numerical study was conducted to investigate the performances of various cut shapes RWS connections with certain overall dimensions and location of the cutting region in terms of hysteresis curves, rupture index and end-plate deformations.
A novel precast tubular web reduced beam section (PTWRBS) connection was proposed in this paper. The structure consists of a steel beam and a concrete-filled steel tubular column, which are spliced together by a prefabricated tubular web splice section, enable realize the function of post-earthquake resilience. To study the seismic performance of the PTWRBS connection, the commonly used bolted-welded (BASE) connection and PTWRBS connection were subjected to quasi-static tests to compare and analyze their performance in terms of failure modes, hysteresis curves, strain distribution, bearing capacity, ductility, and energy dissipation. After which, the second test was then conducted by replacing only the prefabricated tubular web splice section after the PTWRBS connection test. The results showed that the PTWRBS connection had a higher ductility and energy dissipation capability, with a terminal amplitude of up to 7% compared with the conventional connection. Moreover, the plastic hinge in PTWRBS connection was concentrated in the tubular web splice section. The repaired PTWRBS (REPTWRBS) connection still had a high bearing capacity and ductility. The PTWRBS and REPTWRBS connection both manifested good seismic performance in accordance with the seismic code. Additionally, finite element (FE) analysis software was used to numerically analyze the specimens, and the numerical analysis results were compared with the experimental results to verify the accuracy of the FE model and reveal the failure mechanism of the PTWRBS connection.
Recently a new type of Reduced Beam Section (RBS) connection called “Tubular Web RBS (TW-RBS)” has been numerically and experimentally studied. TW-RBS connections are made by replacing a part of web with a tube or pipe at the desirable location of the beam plastic hinge. This paper aims to numerically investigate the effect of key factors such as position, diameter, and thickness of the tube on the hysteretic behavior of the connection under cyclic load using ABAQUS finite element software. First, a model is used for verification purposes where good correlation with experimental results was achieved. Then, 14 models are defined by varying the key parameters and subjected to cyclic loading. The effects of such factors on the behavior of the connection are investigated in order to find out consequences of probable defects during the implementation of TW-RBS connections or intentional utilizing of other pipes in TW-RBSs. Based on the results, the position of the tube is the most sensitive factor in the behavior of TW-RBS connections and its improper location leads to unreliable design, probable plastic hinge formations in unpredicted regions, and possible failure in the connection zone. On the contrary, diameter and thickness of the tube have negligible effect on the energy dissipation mainly depending on beam section properties.
