• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.603-611
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• 2007

Three interior slab-column connections designed by equal static moments and by different distribution of end and midspan moments were tested. Each test specimen consists of a 4.2 m square slab and a 355 mm square column stub. The slab thickness is 152 mm. Test results showed not only that flat plate systems can undergo considerable redistribution of moments from the uncracked state to final maximum capacity, but also that the distribution of moments is controlled largely by the distribution of reinforcement adopted by the designer. Tests also indicated that the punching shear strength of slabs can be affected by the redistributed moments.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.3
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• pp.7-12
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• 2013

The demand for the structural system of reduction of story height increases because buildings are getting higher. The existing structural systems are not efficiency. Thus, it is hard to reduce the story height and existing methods cannot secure economics as expected. This study aims at developing the partially concrete-filled new type composite beam, which can efficiently resist against the end negative moment and central positive moment, also reduce deflection of beams. Through case studies on loading of concentrated load and uniformly distributed load to fixed beam, we could find the most efficient ratio of moment of inertia and the ratio ${\alpha}$(end beam length to span). The gap space between middle and end beam can be used as facilities installation, consequently the suggested Omega beam system is expected to get the effect of reduction in story height as well as reduction of quantity.

• Steel and Composite Structures
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• v.31 no.5
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• pp.427-435
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• 2019

The estimation of moment and rotation in steel rack connections could be significantly helpful parameters for designers and constructors in the initial designing and construction phases. Accordingly, Extreme Learning Machine (ELM) has been optimized to estimate the moment and rotation in steel rack connection based on variable input characteristics as beam depth, column thickness, connector depth, moment and loading. The prediction and estimating of ELM has been juxtaposed with genetic programming (GP) and artificial neural networks (ANNs) methods. Test outcomes have indicated a surpass in accuracy predicting and the capability of generalization in ELM approach than GP or ANN. Therefore, the application of ELM has been basically promised as an alternative way to estimate the moment and rotation of steel rack connection. Further particulars are presented in details in results and discussion.

• Steel and Composite Structures
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• v.35 no.4
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• pp.579-598
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• 2020

Consideration of the panel zone (PZ) deformations in the analysis of steel moment frames (SMFs) has a substantial effect on structural response. One way to include the PZ effect on the structural response is Krawinkler's PZ model, which is one of the best and conventional models. However, modeling of Krawinkler's PZ model has its complexity, and finding an alternative procedure for PZ modeling is of interest. In this study, an efficient model is proposed to simplify Krawinkler's PZ model into an Adjusted Rigid-End Zone (AREZ). In this way, the rigid-end-zone dimensions of the beam and column elements are defined through an appropriate rigid-end-zone factor. The dimensions of this region depend on the PZ stiffness, beam(s) and columns' specifications, and connection joint configuration. Thus, to obtain a relationship for the AREZ model, which yields the dimensions of the rigid-end zone, the story drift of an SMF with Krawinkler's PZ model is equalized with the story drift of the same structure with the AREZ model. Then, the degree of accuracy of the resulting relationship is examined in several connections of generic SMFs. Also, in order to demonstrate the applicability of the proposed model in SMFs, several SMFs ranging from 3- to 30-story representing low- to high-rise buildings are examined through linear static and dynamic time history analysis. Furthermore, non-linear dynamic analyses of three SMFs conducted to validate the degree of accuracy of the proposed model in the non-linear analysis of SMFs. Analytical results show that there is considerable conformity between inter-story drift ratio (IDR) results of the SMFs with Krawinkler's PZ model and those of the centerline SMFs with AREZ.

• Advances in concrete construction
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• v.9 no.1
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• pp.23-31
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• 2020

Geometric nonlinearity can significantly affect load-carrying capacity of slender columns. Dependence of structural stability on columns necessitates the consideration of second-order effects in the design process of columns, appropriately. On the whole, the design codes present a simplified procedure for second order analysis of slender columns. In this approximate method, the end moments of columns resulted from linear analysis (first-order) are multiplied by the recommended moment amplification factors of codes to achieve magnified moments of the second-order analysis. In the other approach, the equilibrium equations are directly solved for the deformed configuration of structure, so the resulting moments and deflections contain the influence of slenderness and increase more rapidly than do loads. The aim of this study is to evaluate the accuracy of moment amplification factors of Iranian national building code whose provisions are similar to the ACI requirement. Herein, finite element method is used to achieve magnified end moments of reinforced concrete moment resisting frames, and the outcomes are compared with the moments acquired based on the proposed approximate method by Iranian national building code. The results show that the approximate method of Iranian code for calculating magnified moments has significant errors for both unbraced and braced columns.

• Journal of Korean Association for Spatial Structures
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• v.19 no.1
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• pp.83-91
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• 2019

The BX composite beam is designed to have the same cross-section regardless of the size of the momentum, which is a disadvantage of the existing steel structure. Combination of the H-beam end compressive material and the H-section steel tensile reinforcement according to the moment size in a single span, It is possible to say that it is an excellent synthesis which increases the performance. When underground and overhead structures are constructed, it is possible to reduce the bending, increase lateral stiffness, reduce construction cost, and simplify joints. The seamability of the joining part is a simple steel composite beam because of the decrease of the beam damping at the center of the beam and the use of the end plate of the new end compressing material. In the case of structures with long span structure and high load, it is advantageous to reduce the material cost by designing large steel which is high in price at less than medium steel.

• Steel and Composite Structures
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• v.47 no.3
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• pp.315-337
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• 2023

The steel structure is an assembly of individual structural members joined together by connections. The connections are the focal point to transfer the forces which is susceptible to damage easily. It is challenging to replace the affected connection parts after an earthquake. Hence, steel plates are utilised as a structural fuse that absorbs connection forces and fails first. The objective of the present research is to develop a beam-column end plate connection with single and dual fuse and study the effect of single fuse, dual fuse and combined action of fuse and damper. In this research, seismic resilient beam-column end plate connection is developed in the form of structural fuse. The novel connection consists of one main fuse was placed horizontally and secondary fuse was placed vertically over main fuse. The specimens are fabricated with the variation in number of fuse (single and dual) and position of fuse (beam flange top and bottom). From the fabricated ten specimens five specimens were loaded monotonically and five cyclically. The experimental results are compared with Finite Element Analysis results of Arunkumar and Umamaheswari (2022). The results are critically assessed in the aspect of moment-rotation behaviour, strain in connection components, connection stiffness, energy dissipation characteristics and ductility. While comparing the performance of total five specimens, the connection with fuse exhibited superior performance than the conventional connection. An equation is proposed for the moment of resistance of end-plate connection without and with structural fuse.

• Structural Engineering and Mechanics
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• v.89 no.2
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• pp.155-170
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• 2024

Several types of column-beam connections are used in the design of steel structures. This situation causes different cross-section effects and, therefore, different displacements and deformations. In other words, connection elements such as welds, bolts, continuity plates, end plates, and stiffness plates used in steel column-beam connections directly affect the section effects. This matter reveals the necessity of knowing the steel column-beam connection behaviours. In this article, behaviours of bolted column-beam connection with end plate widely used in steel structures are investigated comparatively the effects of the stiffness plates added to the beam body, the change in the end plate thickness and bolt diameter. The results obtained reveal that the moment and force carrying capacity of the said connection increases with the increase in the end plate thickness and bolt diameter. In contrast, it causes the other elements to deform and lose their capacity. This matter shows that optimum dimensions are very important in steel column-beam connections. In addition, it has been seen that adding a stiffness plate to the beam body part positively contributes to the connection's moment-carrying capacity.

• Structural Engineering and Mechanics
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• v.91 no.6
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• pp.643-656
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• 2024

The prediction of the moment rotation behavior of semi-rigid connections has been the subject of extensive research. However, to improve the accuracy of these predictions, there is a growing interest in employing machine learning algorithms. This paper investigates the effectiveness of using Multi-gene genetic programming (MGGP) to predict the moment-rotation behavior of flush-end plate connections compared to that of artificial neural networks (ANN) and previous studies. It aims to automate the process of determining the most suitable equations to accurately describe the behavior of these types of connections. Experimental data was used to train ANN and MGGP. The performance of the models was assessed by comparing the values of coefficient of determination (R²), maximum absolute error (MAE), and root-mean-square error (RMSE). The results showed that MGGP produced more accurate, reliable, and general predictions compared to ANN and previous studies with an R² exceeding 0.99, an RMSE of 6.97, and an MAE of 38.68, highlighting its advantages over other models. The use of MGGP can lead to better modeling and more precise predictions in structural design. Additionally, an experimentally-based regression analysis was conducted to obtain the rotational capacity of FECs. A new equation was proposed and compared to previous ones, showing significant improvement in accuracy with an R² score of 0.738, an RMSE of 0.014, and an MAE of 0.024.

• Steel and Composite Structures
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• v.18 no.6
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• pp.1423-1450
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• 2015

The paper presents the details and results of an experimental study on bolted end-plate joints of industrial type steel building frames. The investigated joints are commonly used in Lindab-Astron industrial buildings and are optimized for manufacturing, erection and durability. The aim of the research was to provide an experimental background for the design model development by studying load-bearing capacity of joints, bolt force distribution, and end-plate deformations. Because of the special joint details, (i.e., joints with four bolts in one bolt-row and HammerHead arrangements), the Eurocode 3 standardized component model had to be improved and extended. The experimental programme included six different end-plate and bolt arrangements and covered sixteen specimens. The steel grade of test specimens was S355, the bolt diameter M20, whereas the bolt grade was 8.8 and 10.9 for the two series. The end-plate thickness varied between 12 mm and 24 mm. The specimens were investigated under pure bending conditions using a four-point-bending test arrangement. In all tests the typical displacements and the bolt force distribution were measured. The end-plate plastic deformations were measured after the tests by an automatic measuring device. The measured data were presented and evaluated by the moment-bolt-row force and moment-distance from centre of compression diagrams and by the deformed end-plate surfaces. From the results the typical failure modes and the joint behaviour were specified and presented. Furthermore the influence of the end-plate thickness and the pretension of the bolts on the behaviour of bolted joints were analysed.