• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.327-338
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• 1998

This paper presents the elastic behavior for panel zone and flange of connection in steel frame pier. The results of stress distributions on a series of experiments and FEM analysis models are reported herein. The investigations show that the shear stresses in the panel zone are varied with sectional-area ratio$(A_f/A_w)$ and also indicate that the nomal stresses in the flange due to the shea lag are significantly higher than the current design procedure. Based on the results, some new proposals considering the design parameters affecting connecting behavior are presented for the evaluations of stresses of panel zone and flange in connection.

• Steel and Composite Structures
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• v.26 no.1
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• pp.31-44
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• 2018

This paper reports a novel steel beam-to-column connection suitable for use in the weak axis of I-section column. Monotonic and cyclic loading experimental investigations and numerical analysis of the proposed weak-axis connection were conducted, and the calculation procedure of the beam-column relative rotation angle and plastic rotation angle was developed and described in details. A comparative analysis of mechanical property and steel consumption were employed for the proposed I-section column weak-axis connection and box-section column bending connection. The result showed that no signs of fracturing were observed and the plastic hinge formed reliably in the beam section away from the skin plate under the beam end monotonic loading, and the plastic hinge formed much closer to the skin plate under the beam end cyclic loading. The fracture of welds between diaphragm and skin plate would cause an unstable hysteretic response under the column top horizontal cyclic loading. The proposed weak-axis connection system could not only simplify the design calculation progress when I-section column is adopted in frame structural design but also effectively satisfy the requirements of 'strong joint and weak member', as well as lower steel consumption.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.3
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• pp.243-250
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• 2004

In SPS system, steel beams are used as not only temporary struts supporting the wale but main flexural members of building. Previous experimental works show that RC wale-steel beam joints have some flexural rigidity. In this paper, nonlinear analysis is performed using DRAIN-2DX program to investigate the behaviors of the underground composite frames constructed with SPS system when the rigidity of RC wale-steel beam joints change. Analysis variables are the procedure of construction, magnitude of lateral forces, and flexural rigidity of the RC wale-steel beam joint with stud connector. Analysis results show the effects of joint rigidity for the yielding process of frame and the moment and deflection at the mid-span of beam.

• Journal of Welding and Joining
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• v.32 no.2
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• pp.54-62
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• 2014

Manhole cover, which is usually made of grey cast iron and consists of frame and cover, should have enough strength to support the heavy traffic load. The manhole cover made of cast iron has heavy weight to handle manually and is vulnerable to impact force with its brittle characteristics. Moreover, its production process of casting has been regulated in terms of environmental pollution. In this study, steel manhole cover is proposed to substitute the cast cover with a series of structural analyses to confirm its strength to support the test load for manhole cover. The cover of the proposed steel manhole cover is made of thin circular pate and stiffeners below the plate. Rectangular columns and hollow circular plate were selected for the shape of the stiffener. In order to give enough strength for the cover to behave within elastic range in the loading, strengthening structures of the cover were varied with increasing the number and the size of the stiffeners. The results of the analyses revealed that when both the hollow circular stiffener and cross stiffeners were additionally applied at the same time to the steel cover with longitudinal stiffeners, the maximum stress level in the cover could be reduced to that level presented in the cast cover.

• Steel and Composite Structures
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• v.20 no.2
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• pp.357-378
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• 2016

The progressive collapse phenomenon in structures has been interested by civil engineers and the building standards organizations. This is particularly true for the tall and special buildings ever since local collapse of the Ronan Point tower in UK in 1968. When initial or secondary defects of main load carrying elements, overloads or unpredicted loads occur in the structure, a local collapse may be arise that could be distributed through entire structure and cause global collapse. One is not able to prevent the reason of failure as well as the prevention of propagation of the collapse. Also, one is not able to predict the start point of collapse. Therefore we should generalize design guides to whole or the part of structure based on the risk analysis and use of load carrying elements removal scenario. There are some new guides and criteria for elements and connections to be designed to resist progressive collapse. In this paper, codes and recommendations by various researchers are presented, classified and compared for steel structures. Two current design methods are described in this paper and some retrofitting methods are summarized. Finally a steel building with special moment resistant frame is analyzed as a case study based on two standards guidelines. This includes consideration of codes recommendations. It is shown that progressive collapse potential of the building depends on the removal scenario selection and type of analysis. Different results are obtained based on two guidelines.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.1-4
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• 2009

Construction automation and robotics are being introduced as an efficient alternative to overcome troubles caused by lack of skilled labors. To accomplish effective automated construction system, design for automation(DFA) should be performed in parallel with the development of core technologies such as control and sensing of robots. In Korea, the development of robotic crane-based construction automation(RCA) system is progressing, and the research group has recently developed newly designed steel joint to improve the efficiency of the system. However, performance of the new system should be examined prior to its application on construction sites. Therefore, This study analyzed performance of the new steel frame focused on its constructibility by carrying out mock-up test. As a result, the steel frame satisfied the standards of allowable stress and deflection. It also enables to reduce the time for installation.

• Steel and Composite Structures
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• v.36 no.1
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• pp.17-29
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• 2020

This paper presents experimental and numerical studies on the seismic responses of the steel cabinet facility considering the nonlinear behavior of connections and site-response effects. Three finite element (FE) models with differences of type and number of connections between steel plates and frame members have been developed to demonstrate adequately dynamic responses of structures. The screw connections with the bilinear force-deformation relationship are proposed to represent the inelastic behavior of the cabinet. The experiment is carried out to provide a verification with improved FE models. It shows that the natural frequencies of the cabinet are sensitive to the plate and frame connectors. The screw connections reduce the free vibration compared to the weld one, with decreased values of 2.82% and 4.87% corresponding to front-to-back and side-to-side directions. Additionally, the seismic responses are investigated for various geological configurations. Input time histories are generated so that their response spectrums are compatible with a required response spectrum via the time-domain spectral matching. The results indicate that both site effects and nonlinear behavior of connections affect greatly on the seismic response of structures.

• Structural Engineering and Mechanics
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• v.10 no.6
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• pp.589-601
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• 2000

A simplified analysis procedure utilizing the strut-tie modeling technique is developed to take a close look into the post-elastic deformation capacity of beam-column connections in ductile reinforced concrete frame structures. Particular emphasis is given to the effect of concrete strength decay and quantity and arrangement of joint shear steel. For this a fan-shaped crack pattern is postulated through the joints. A series of hypothetical rigid nodes are assumed through which struts, ties and boundaries are connected to each other. The equilibrium consideration enables all forces in struts, ties and boundaries to be related through the nodes. The boundary condition surrounding the joints is obtained by the mechanism analysis of the frame structures. In order to avoid a complexity from the indeterminacy of the truss model, it is assumed that all shear steel yielded. It is noted from the previous research that the capacity of struts is limited by the principal tensile strain of the joint panel for which the strain of the transverse diagonal is taken. The post-yield deformation of joint steel is taken to be the only source of the joint shear deformation beyond the elastic range. Both deformations are related by the energy consideration. The analysis is then performed by iteration for a given shear strain. The analysis results indicate that concentrating most of the joint steel near the center of the joint along with higher strength concrete may enhance the post-elastic joint performance.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.4
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• pp.153-160
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• 2021

The connection of the steel structure serves to transmit external forces to the main components. The same is true for the behavior of modular systems composed mainly of steel or composite members. In this study, the joint performance of the composite and steel modules proposed was evaluated. The analytical models of the two joint types were constructed and were subjected to cyclic loading to assess the safety and the energy dissipation capacity of the joint types. The analysis results of the joints showed that the joints of the modular systems remain stable when the joint rotation reached the seismic performance limit state of the 0.02 rad required for steel intermediate moment frame. It was also observed that the joint of the composite modular system showed higher energy dissipation capacity compared with the steel modular system.

• Steel and Composite Structures
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• v.44 no.5
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• pp.603-617
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• 2022

Structural design, in general, is developed through trial and error technique which is guided by standards criteria and based on the intuition and experience of the engineer, a context that leads to structural over-dimensioning, with uneconomic solutions. Aiming to find the optimal design, structural optimization methods have been developed to find a balance between cost, structural safety, and material performance. These methods have become a great opportunity in the steel structural engineering domain since they have as their main purpose is weight minimization, a factor directly correlated to the real cost of the structure. Assuming an objective function of minimum weight with stress and displacement constraints provided by Brazilian standards, the present research proposes the sizing optimization and combined approach of sizing and shape optimization, through a software developed to implement the Simulated Annealing metaheuristic algorithm. Therefore, two steel plane frame layouts, each admitting four typical truss geometries, were proposed in order to expose the difference between the optimal solutions. The assessment of the optimal solutions indicates a notable weight reduction, especially in sizing and shape optimization combination, in which the quantity of design variables is increased along with the search space, improving the efficiency of the optimal solutions achieved.