• Steel and Composite Structures
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• v.15 no.6
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• pp.679-703
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• 2013

This paper presents experimental investigations of the fundamental behavior of concrete filled steel tube (CFT) beam-columns under fire loading. A total of thirteen specimens were tested to determine the axial force-moment-curvature-temperature behavior of CFT beam-columns. The experimental approach involved the use of: (a) innovative heating and control equipment to apply thermal loading and (b) digital image correlation with close-range photogrammetry to measure the deformations (e.g., curvature) of the heated region. Each specimen was sequentially subjected to: (i) constant axial loading; (ii) thermal loading in the expected plastic hinge region following the ASTM E119 temperature-time T-t curve; and (iii) monotonically increasing flexural loading. The effects of various parameters on the strength and stiffness of CFT beam-columns were evaluated. The parameters considered were the steel tube width, width-tothickness ratio, concrete strength, maximum surface temperature of the steel tube, and the axial load level on the composite CFT section. The experimental results provide knowledge of the fundamental behavior of composite CFT beam-columns, and can be used to calibrate analytical models or macro finite element models developed for predicting behavior of CFT members and frames under fire loading.

• Structural Engineering and Mechanics
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• v.85 no.1
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• pp.89-104
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• 2023

This work presents a proposal for employing reduced numerical integration in the formulation of the 4-node quadrilateral solid finite element. The use of these low-order integration rules leads to numerical instabilities such as those producing the hourglass effect. The proposed procedure allows evaluating a given constitutive model only in one integration point, achieving an attractive computational cost reduction and, also, successfully controls the hourglass effect. A validation of the proposal is included and discussed throughout the paper. To show the efficiency of the proposal, several application examples of masonry structures are studied and discussed. To represent the non-linear mechanical behaviour of masonry a plastic-damage model is implemented within the application of this sub-integration scheme. Also, in order to have a full and computationally efficient strategy to determine the behaviour of masonry structures, involving its evolution to collapse, a homogenization technique with a macro-modeling approach is used. The methodology discussed throughout this paper demonstrates a substantial computational cost reduction and an improved approximation of the non-linear problem evidenced by a reduction of up to 85% of the computational time for some cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6143-6150
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• 2012

The current society, namely information society is now moving to a specific topic which is SMART. In this sense, recently a variety of social areas including communications and SOC domains are moving fast to this topic. In Korea, The electric power area has been doing a pioneering job relatively successfully and the water supply area is just now taking the first step. The purpose of this research is to develop a technical Framework for Smart Water Grid Service. Related researches has been studied and the 4 constituting technical element areas were defined first. For each of the four areas, a framework modeling was fulfilled and as a result, a TRM(Technical Road Map) was suggested for each of the area. Finally, an Enterprise TRM covering all of the 4 areas was described. Furthermore, the currently suggested Framework model was compared to a related model and it was found that the integration of the models is desirable to wholly cover from Macro to Micro level applications and services. It is expected that the current approach contribute, more or less, to the smart implementation in the areas of water management.