scholarly journals DETERMINING THE OPTIMAL GEOMETRY OF RBS CONNECTION FOR ENHANCEMENT OF SEISMIC BEHAVIOR OF STEEL MOMENT FRAMES

2016 ◽  
Vol 38 (2) ◽  
pp. 1116
Author(s):  
Hossein Khosravi ◽  
Vahidreza Kalatjari ◽  
Hadi Einabadi

In a RBS connection, the stress concentration is being prevented on the location of joint via local reduction of beam section near the column and the place of plastic hinge is being transferred from connection to a section of a beam near to the column. A special ilk of RBS connection which is named dogbone connection and its beam wings are cut from a circle in an arcuate form, has displayed a desirable performance against to the seismic loads. This paper aims at obtaining the best cutting geometry of the beam wing in order to improve the performance of the connection against to the seismic loads. For this purpose in this research, we have opted a several panel zone with different dimension on the beam wing under the influence of the seismic loads in Finite Element software called Abaqus along with a cyclic loading, modeled displacement control index and the best sample of cutting dimension among from the samples that are modeled.

2021 ◽  

Connections are considered to be one of the most prominent components of steel moment frames and have received studious attention in recent years. The core problem of welded connections is premature brittle fracture of weld in the critical beam-to-column connection region. Within the framework of this issue, various approaches have been proposed to solve the mentioned problem. Intentional weakening of the beam web or flange is in line with the purpose of leading the plastic hinge away from the column face, hence, increasing the ductility. The aim of this research is to investigate the behavior of interior connections subjected to monotonic lateral loading in case of presence of openings in beam web or flange. To do so, an ordinary fully welded rigid connection, reduced beam section, reduced web section, and drilled flange connection models are simulated numerically, utilizing finite element software, ANSYS. The results indicate that scrupulous selection of opening sizes are of great importance to fulfill the desired outcome which is avoiding the brittle failure of connections. Furthermore, the use of drilled flange, reduced beam section, or reduced web section connections satisfy the expected performance and it is proposed to use them according to practicability, architectural and economic considerations as well as site conditions. Shear deformation and local buckling is observed in reduced web section connections while in drilled flange connections, stress concentration around the opening is critical.


2020 ◽  
Vol 20 (06) ◽  
pp. 2040005
Author(s):  
Han Peng ◽  
Jinping Ou ◽  
Andreas Schellenberg ◽  
Frank Mckenna ◽  
Stephen Mahin

This paper presents an investigation on the seismic behavior of steel moment frames with mechanical hinge beam-to-column connections. The connection uses a mechanical hinge to carry shear force and a pair of buckling-restrained steel plates bolted to the beam flange to transfer bending moment. The moment-rotation behavior of the connection was theoretically studied. A nonlinear numerical model for steel moment frames under strong earthquakes was developed and validated using a shaking table test of an 18-story steel moment frame at the E-Defense facility. Then, nonlinear static and time-history analyses were conducted to compare the seismic behavior of a conventional steel moment frame and three innovative steel frames equipped mechanical hinge connections in terms of roof displacement, base shear, inter-story drift ratio, and plastic hinge rotation.


2011 ◽  
Vol 94-96 ◽  
pp. 668-673
Author(s):  
Yan Wang ◽  
Li Ya Zhang ◽  
Shuang Feng ◽  
Xiang Gao

14 models of plate-reinforced connections are analyzed by finite element software ANSYS. Failure mode, hysteretic behavior, ductility and energy dissipation capacity are comparatively studied. Results show that plastic hinge formed at the end of the reinforced plate, hysteretic cruves are full and the connections have good ductility. With the increase in length and thickness of the reinforced plate, bearing capacity increases while hysteretic behavior and ductility factor decrease. If the reinforced plate is longer than the length that design requires, brittle failure occurs in the panel zone. The recommended length of the reinforced plate is defined as 0.5-0.8 times of beam depth, the thickness of flange-plate is 1.2-1.4 times of flange thickness and the thickness of cover-plate is 0.7-1.2 times of flange thickness.


2021 ◽  
Author(s):  
Hamidreza Nazaralizadeh ◽  
Hamid Ronagh ◽  
Parham Memarzadeh ◽  
Farhad Behnamfar

Abstract 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.


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