• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.383-394
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• 2021

Column foot in traditional Chinese timber structures may be subjected to be uplifted due to the lateral load and subsequently reset under the vertical loads. The residual moment of the rocking column foot is the most important parameter representing the mechanical behaviors of column foot, and the simplification of joints is the basis of structural analysis of whole structure. The complicated mechanical behaviors of joint and the modeling of the column foot joint has been undertaken historically based on the experiments and numerical simulation. On the condition of limited application range of those models, a lack of simplified model to represent the mechanical behaviors of joint deserves attentions. There is a great need to undertake theoretical studies to derive the residual moment and make better simplified model of the joint. This paper proposes the residual moment and equivalent simplified model of the rotational stiffness for column foot joint. And, the timber frame is established based on the simplified model, which is verified by solid finite element model. Results show that a mutual agreement on the mechanical behaviors of the timber frame is obtained between the simplified model and the solid finite element model. This study can serve as the references of the structural analysis for the traditional timber structures.

• Steel and Composite Structures
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• v.19 no.2
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• pp.467-484
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• 2015

Seismic performances of dual steel moment-resisting frames with mixed use of rigid and semi-rigid connections were investigated to control of the base shear, story drifts and the ductility demand of the elements. To this end, nonlinear seismic responses of three groups of frames with three, eight and fifteen story were evaluated. These frames with rigid, semi-rigid and combined configuration of rigid and semi-rigid connections were analyzed under five earthquake records and their responses were compared in ultimate limit state of rigid frame. This study showed that in all frames, it could be found a state of semi-rigidity and connections configuration which behaved better than rigid frame, with consideration of the base shear and story drifts criterion. Finally, some criteria were suggested to locate the best place of the semi-rigid connections for improvement of the seismic performance of steel moment-resisting frames.

• Earthquakes and Structures
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• v.11 no.4
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• pp.609-627
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• 2016

Results of an experimental program are presented in this paper for the influence of vertical load on the in-plane behavior of masonry infilled steel frames. Five half-scaled single-story, single-bay steel frame specimens were tested under cyclic lateral loading. The specimens included four infilled frames and one bare frame. Two similar specimens as well as the bare frame had moment-resisting steel frames, while the remaining two specimens had pinned steel frames. For each frame type, one specimen was tested under simultaneous vertical and lateral loading, whereas the other was subjected only to lateral loading. The experimental results show that the vertical load changes the cracking patterns and failure modes of the infill panels. It improves dissipated hysteresis energy and equivalent viscous damping. Global responses of specimens, including stiffness and maximum strength, do no change by vertical loading considerably. Regarding the ductility, the presence of vertical load is ignorable in the specimen with moment-resisting frame. However, it increases the ductility of the infilled pinned frame specimen, leading to an enhancement in the m-factor by at least 2.5 times. In summary, it is concluded that the influence of the vertical load on the lateral response of infilled frames can be conservatively ignored.

• Journal of the Korean Wood Science and Technology
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• v.23 no.3
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• pp.8-15
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• 1995

This analytical study was carried out to make quality and productivity up in designing the frame-type furniture with semi-rigid joint by understanding the mechanical and structural behavior of the joint and by evaluating the validity of application of the time-saving Finite Element Method to its structural analysis. Slope deflection equation for rigid joint was modified to describe the moment-rotation behavior of semi-rigid joint and the joint stiffness factor(Z) could be calculated to lessen the experimental expense. It was proved that Finite Element Analysis with imaginary elements having equivalent MOE to the semi-rigid joint could be the alternative method for the structural analysis of the frame-type furniture, comparing the internal rotation of the 2-dimensional beam-to-column model with two-pin(wooden dowel) from the finite element method with other available theoretical and experimental rotation value.

• Steel and Composite Structures
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• v.27 no.3
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• pp.337-353
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• 2018

In previous weak-axis moment connection tests, brittle fracture always initiated near the edge of the beam flange groove weld due to force flow towards the stiffer column flanges, which is the opposite pattern as strong-axis moment connections. As part of the China NSFC (51278061) study, this paper tested two full-scale novel weak-axis reduced beam section moment connections, including one exterior frame connection specimen SJ-1 under beam end monotonic loading and one interior frame joint specimen SJ-2 under column top cyclic loading. Test results showed that these two specimens were able to satisfy the demands of FEMA-267 (1995) or ANSI/AISC 341-10 (2010) without experiencing brittle fracture. A parametric analysis using the finite element software ABAQUS was carried out to better understand the cyclic performance of the novel weak-axis reduced beam section moment connections, and the influence of the distance between skin plate and reduced beam section, a, the length of the reduced beam section, b, and the cutting depth of the reduced beam section, c, on the cyclic performance was analyzed. It was found that increasing three parametric values reasonably is beneficial to forming beam plastic hinges, and increasing the parameter a is conducive to reducing stress concentration of beam flange groove welds while increasing the parameters b and c can only reduce the peak stress of beam flange groove welds. The rules recommended by FEMA350 (2000) are suitable for designing the proposed weak-axis RBS moment connection, and a proven calculation formulation is given to determine the thickness of skin plate, the key components in the proposed weak-axis connections. Based on the experimental and numerical results, a design procedure for the proposed weak-axis RBS moment connections was developed.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.28-35
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• 2017

In this study, specimens of rigid frame joint were produced by integrating joints with adhesive and other specimens were produced by inserting a wooden gusset integrated with a column member into a slit-processed beam member and joining them with pins. Then the moment resistance performances of the specimens were examined. For the wooden gusset, a GFRP-reinforced wooden gusset was used. The calculation results of perfect elasto-plasticity for the frame specimens for which a GFRP-reinforced wooden gusset was inserted into and joined with the slit-processed beam member by pins were 20-80% lower compared to the control group which consisted of steel plate-inserted frame specimens. The rigid frame specimens for which the column and beam members have been integrated with adhesive showed almost no initial residual transformations, as well as 38% greater initial rigidity and 41% greater plasticity compared to the steel plate-inserted joint.

• KIEAE Journal
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• v.10 no.6
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• pp.159-165
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• 2010

The composite frame system suggested in this paper consists of steel reinforced concrete beam encased with structural tee and precast concrete column. This system has advantages such as reduction of materials, CO2 emissions and waste. To commercialize the new composite frame system, it is necessary to develop connections that can effectively connect each member. Therefore, a hybrid connection that has steel type connection and reinforced concrete together is utilized to connect easily at the composite frame system. To evaluate the structural performance of the composite frame system, an experimental investigation is presented. In this study, the flexural moment capacity of the composite frame was determined using the strain compatibility approach. The strain compatibility approach can be used to predict the flexural moment capacity at each limit state. As a result, all elements of the beam to column connection are represented to fully interact between each other. The specimens show errors of -1.9% in the yield limit state and 0.9% at the maximum load limit state. Also, testing shows that beam to column connections have characteristics of semi-rigid connection as per Eurocode 3.

• Journal of Korean Society of Steel Construction
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• v.24 no.5
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• pp.511-520
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• 2012

The double split Tee connection, a type of full strength-partially restrained connection, has adequate flexural strength according to the changes in the thickness of the T-stub flange and the gauge distance of the high-strength bolts. Moreover, the double split Tee connection is designed and constructed with seismic connections that have enough ductility capacity applicable to ordinary moment frame and special moment frame by grade of steel, size of beam and column and geometric connection shape. However, such a domestic research and a proposal of a suitable design formula about the double split Tee connection are insufficient. Thus, many experimental and analytical studies are in need for the domestic application of the double split Tee connection. Therefore, this study aimed to examine and suggest feasibility of a design formula of the double split Tee connection of FEMA.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.39-45
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• 2007

In this study the probability and the reliability-based seismic performance evaluation procedure proposed in the FEMA-355F was applied to a reinforced concrete moment frame building. For the FEMA procedure, which was originally developed for steel moment frame structures, to be applied to other structural systems, the capacity should be re-defined and the factors reflecting the uncertainties related to capacity and demand need to be determined. To perform the evaluation procedure a prototype building was designed per IBC 2003, and inelastic dynamic analyses were conducted applying site-specific ground motions to determine the parameters for performance evaluation. According to the analysis results, distribution of the determined capacities turned out to be relative]y smaller than that of the demands, which showed that the defined capacity was reasonable. It was also shown that the prototype building satisfied the target performance since the determined confidence levels exceeded the otjectives for both local and global collapses.

• Journal of Korean Association for Spatial Structures
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• v.20 no.3
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• pp.27-34
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• 2020

This paper examines the seismic performance and structural design of the ceiling bracket-type modular connection. The bracket-type system reduces the cross-sectional area loss of members and combines units using fitting steel plate, and it has been developed to be fit for medium-story and higher-story buildings. In particular, this study conducted the cyclic loading test for the performance of the C-type and L-type brackets, and compared the results. The test results were also compared with the commercial FEA program. In addition, the structural design process for the bracket-type modular connection was presented. The two connections, proposed as a result of the test results, were all found to secure the seismic performance level of the special moment steel frame. In the case of initial stiffness, the L-type bracket connection was found to be great, but in the case of the maximum moment or fully plastic moment, it was different depending on the loading direction.