The beneficial effects of beam web opening in seismic behavior of steel moment frames

In this two-part work, seismic behavior and design of steel moment frames with masonry infills are investigated systematically. In this first part, the “infill strength ratio” (the ratio of the story shear strength of infills to the story shear strength of the bare frame) is shown to have a fundamental effect on the seismic behavior of an infilled frame. This fundamental effect is demonstrated using pushover analysis of an example steel moment frame with masonry infills in uniformly infilled and open ground story configurations. In general, infill strength ratios greater than about 0.35 are associated with progressive deterioration of seismic performance, leading to story mechanisms concentrated in the lower stories. Greater infill strength ratios can also lead to local shear failures in frame members.

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Study on Seismic Performance of a New Type Energy Dissipation Steel Moment Frames

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.94-96.764 ◽

2011 ◽

Vol 94-96 ◽

pp. 764-770

Author(s):

Bing Guo ◽

Jin Tao Wang ◽

Tian Liang ◽

Zhen Bao

Keyword(s):

Energy Dissipation ◽

Axial Stress ◽

Design Criterion ◽

Moment Frames ◽

Steel Moment Frames ◽

Web Openings ◽

Web Opening ◽

Open Circular ◽

Circular Holes ◽

New Type

Open circular holes with a certain size in beam web at 1/6 span is a new method to improve the seismic behavior of steel moment frames. Based on the results of elasticity theory, analytical model of frame with opening web is proposed, and analysis and verification with nonlinear finite element method (FEM) are conducted. Results show that, beam with opening web at 1/6 span can significantly reduce the axial stress of beam flange near the beam-column connections. It is helpful to achieve the design criterion of strong connection and weak member, and also to simplify the connection construction. If the diameter of web opening is appropriate, beam plastic hinges can move inward to beam section at opening web, and has little effect on bearing capacity, stiffness, energy dissipation capacity and ductility of frames. The method of web openings and the size range are presented at the end of this paper.

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Seismic Behavior of Steel Moment Frames with Mechanical Hinge Beam-to-Column Connections

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455420400052 ◽

2020 ◽

Vol 20 (06) ◽

pp. 2040005

Author(s):

Han Peng ◽

Jinping Ou ◽

Andreas Schellenberg ◽

Frank Mckenna ◽

Stephen Mahin

Keyword(s):

Seismic Behavior ◽

Shaking Table Test ◽

Plastic Hinge ◽

Time History ◽

Shaking Table ◽

Base Shear ◽

Moment Frames ◽

Steel Moment Frames ◽

Moment Frame ◽

Steel Moment Frame

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.

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Evaluation of seismic capacity and response according to the nonlinear modeling approach of members in steel moment frames

International Journal of Engineering and Technology ◽

10.21817/ijet/2021/v13i3/211303010 ◽

2021 ◽

Vol 13 (3) ◽

pp. 104-115

Author(s):

Alireza Kian Mehr

Keyword(s):

Seismic Behavior ◽

Nonlinear Modeling ◽

Nonlinear Static Analysis ◽

Moment Frames ◽

Steel Moment Frames ◽

Seismic Capacity ◽

Beam Elements ◽

Nonlinear Static ◽

The Difference ◽

Middle Member

In this paper, the aim is to evaluate the seismic behavior of steel momment frames by nonlinear static analysis and incremental dynamic analysis. In this regard, 5 and 10 story frames in both intermediate and special ductility have been used. Since the type of sections and elements used in modeling are among the parameters that affect the behavior of the structure, in this study, which was performed using Opensees software, fiber sections were used for two types of beam elements. Non-linear column (distributed plasticity) and articulated beam element (concentrated plasticity) are used. The results of the analysis show that the ratio of the collapse capacity of the frames to each other varies between 1% to 6%. On the other hand, by deepening the research on one of the frames, it was shown that the stiffness ratio between the end springs and the middle member will affect the difference between the collapse capacity shown in the analysis.

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

Ciência e Natura ◽

10.5902/2179460x20076 ◽

2016 ◽

Vol 38 (2) ◽

pp. 1116

Author(s):

Hossein Khosravi ◽

Vahidreza Kalatjari ◽

Hadi Einabadi

Keyword(s):

Seismic Behavior ◽

Plastic Hinge ◽

Seismic Loads ◽

Moment Frames ◽

Steel Moment Frames ◽

Finite Element Software ◽

Cutting Geometry ◽

Panel Zone ◽

Local Reduction ◽

Beam Section

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.

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Effects of Fling Step and Forward Directivity on Seismic Response of Buildings

Earthquake Spectra ◽

10.1193/1.2192560 ◽

2006 ◽

Vol 22 (2) ◽

pp. 367-390 ◽

Cited By ~ 255

Author(s):

Erol Kalkan ◽

Sashi K. Kunnath

Keyword(s):

Seismic Response ◽

Ground Motions ◽

High Amplitude ◽

Moment Frames ◽

Steel Moment Frames ◽

Damage Potential ◽

Near Fault ◽

Forward Directivity ◽

Fling Step ◽

Far Fault

This paper investigates the consequences of well-known characteristics of near-fault ground motions on the seismic response of steel moment frames. Additionally, idealized pulses are utilized in a separate study to gain further insight into the effects of high-amplitude pulses on structural demands. Simple input pulses were also synthesized to simulate artificial fling-step effects in ground motions originally having forward directivity. Findings from the study reveal that median maximum demands and the dispersion in the peak values were higher for near-fault records than far-fault motions. The arrival of the velocity pulse in a near-fault record causes the structure to dissipate considerable input energy in relatively few plastic cycles, whereas cumulative effects from increased cyclic demands are more pronounced in far-fault records. For pulse-type input, the maximum demand is a function of the ratio of the pulse period to the fundamental period of the structure. Records with fling effects were found to excite systems primarily in their fundamental mode while waveforms with forward directivity in the absence of fling caused higher modes to be activated. It is concluded that the acceleration and velocity spectra, when examined collectively, can be utilized to reasonably assess the damage potential of near-fault records.

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