• International Journal of High-Rise Buildings
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• v.4 no.1
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• pp.45-55
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• 2015

The rotation capacity of the moment connections could significantly influence on the seismic performance of steel moment resisting frames. Current seismic provisions require that beam-to-column connections in Intermediate Moment Frames (IMF) should have a drift capacity as large as 0.02 radian. The objective of this study was to evaluate the effect of the rotation capacity of moment connections on the seismic performance of high-rise IMFs. For this purpose, thirty- and forty-story high-rise IMFs were designed according to the current seismic design provisions. The seismic performance of designed model frames was evaluated according to FEMA P695. This study showed that the forty-story IMF satisfied the seismic performance objective specified in FEMA P695 when the rotation capacity of the connections was larger than 0.02. However, thirty-story IMFs satisfied the performance objective when the connection rotation capacity is larger than 0.03.

• Journal of Korean Society of Steel Construction
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• v.15 no.5 s.66
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• pp.551-559
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• 2003

In steel frames, the analysis and design techniques are based on either idealized fixed or pinned connections. In this case, it has the advantage that the structural analysis and the design procedure were simplified, but there could be given different results of analysis between the real steel frame connections and the idealized fixed and pinned connection. This is because the real connections would be analyzed by semi-rigid, and have some transfer of moment and rotational constraint about the loads. In this study, structural analysis program with considered connections that have joint rigidity of fixed, pinned and semi-rigid, was developed. Then, the effects of joint rigidity on strength and displacement. in steel frames subjected to lateral forces and axial forces, were investigate, and the results were compared with those of the Midas Gen. w program.

• Steel and Composite Structures
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• v.33 no.3
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• pp.357-373
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• 2019

Steel storage racks are slender structures whose overall behavior and the capacity depend largely on the flexural behavior of the base-plate to upright connections and on the behavior of beam-to-column connections. The base-plate upright connection assembly details, anchor bolt position in particular, associated with the high-rise steel storage racks differ from those of normal height steel storage racks. Since flexural behavior of high-rise rack base connection is hitherto unavailable, this investigation experimentally establishes the flexural behavior of base-plate upright connections of high-rise steel storage racks. This investigation used an enhanced test setup and considered nine groups of three identical tests to investigate the influence of factors such as axial load, base plate thickness, anchor bolt size, bracket length, and upright thickness. The test observations show that the base-plate assembly may significantly influence the overall behavior of such connections. A rigid plate analytical model and an elastic plate analytical model for the overall rotations stiffness of base-plate upright connections with concentric anchor bolts were constructed, and were found to give better predictions of the initial stiffness of such connections. Analytical model based parametric studies highlight and quantify the interplay of components and provide a means for efficient maximization of overall rotational stiffness of concentrically anchor bolted high-rise rack base-plate upright connections.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.8-14
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• 2011

Japanese larch glulam was used as structural members to develop a modern engineered wood jointing system using traditional post and beam structure. For the connections comprised of traditional joining and drift-pins, structural members are processed at a pre-cut factory. As a basic study to examine and increase the whole shear performance of portal frame, pin withdrawal test and moment resistance tests were conducted on each connection. The post and beam members with specified connectors showed good bearing performance in the wood members' joining system, column-base and beam-end. Moment rigidity was a bit better in a joint with higher slenderness ratio of drift-pin, but moment resistance performances, yield moment and maximum moment, were excellent in smaller one.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.527-535
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• 2000

Accurate determination of the relative restraint of beam-to-column connections is important for both the strength and the serviceability of structural frames. But steel frame analysis is carried out under the assumption that the connections are either fixed or pinned. Overestimating the connection restraint can result in underestimating lateral sway and underestimating the connection restraint can lead to underestimating forces developed in the beams and columns. This implies that the exact stiffness of connections as well as the geometric effects should be considered in the frame analysis and the overall behavior of connections could be described adequately. Therefore, the stiffness matrix which is able to consider the moment-rotation of connection was derived previously and the modified exponential model, power model and the proposed log model are adopted for modeling the semi-rigid connections. The main purpose of this study is to examine the feasibility of the derived stiffness matrix and to show the validity of log model proposed.

• Journal of Korean Society of Steel Construction
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• v.29 no.6
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• pp.423-434
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• 2017

In this paper a systematic numerical analysis is performed to obtain the hysteresis behavior of partially restrained top and seat angle connections subjected to cyclic loading. This connection includes superelastic shape memory alloy (SMA) angles and rods in order to secure the recentering capacities as well as proper energy dissipation effects of a CFT composite frame. The three-dimensional nonlinear finite element models are constructed to investigate the rotational stiffness, bending moment capacity and failure modes. A wide scope of additional structural behaviors explain the different influences of the connection's parameters, such as the various thickness of connection angles and the gage distance of steel and SMA rods.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.629-639
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• 2004

A steel frame is one of the most commonly used structural systems due to its resistance to various types of applied loads. Many studies have been conducted to investigate the effects of several parameters, such as connection flexibility, the boundary condition of each support, and beam-to-column stiffness ratio, on the characteristic behavior of a frame. Based on the results of these studies, several design methods have been proposed. This research focused on the number of bolts on the rotational stiffness of a double-angle connection, and its effect on the story drift of a frame. To achieve these purposes, a simplified analytical model was proposed. Several experimental tests were also conducted to obtain the rotational connection stiffness of each double-angle connection.

• Steel and Composite Structures
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• v.8 no.3
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• pp.243-264
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• 2008

This paper details a testing facility ("NATURAL FIRE FACILITY") that allows closely-controlled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6527-6533
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• 2013

A fish-bone girder pier affects torsion severely because of the one girder system. This study was performed to develop an analytical model to analyze and design a fish-bone girder pier properly. This model consisted of a beam element with 7-degrees of freedom considering the warping rigidity. Several beam-column connection conditions were considered. The static load test was performed using a real size specimen. The validity of this model was tested by a comparison of the analytical results with the experimental results. This analytical model is useful for designing the bolt connection of a Spine girder.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.35-46
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• 1998

Structural damage is used to be modeled through reductions in the stiffness of structural elements for the purpose of damage estimation of structural system. In this study, the concept of joint damage is employed for more realistic damage assessment of a steel structure. The joint damage is estimated damage based on the mode shape informations using neural networks, The beam-to-column connection in a steel frame structure is represented by a rotational spring at the fixed end of a beam element. The severity of joint damage is defined as the reduction ratio of the connection stiffness with respect to the value of the intact joint. The concept of the substructural identification is used for the localized damage assessment in a large structure. The feasibility of the proposed method is examined using an example with simulated data. It has been found that the joint damages can be reasonably estimated for the case with the measurements of the mode vectors subjected to noise.