• Steel and Composite Structures
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• v.2 no.6
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• pp.441-460
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• 2002

In the design of bridges, it is important to consider the thermal stresses induced by the non-linear temperature distribution as well as the variation of effective temperature in the bridge deck. To cope with this, design temperature profiles are provided by design codes, which are normally based on extensive research work. This paper presents the results of a comprehensive investigation on the thermal behaviour of bridges in Hong Kong with special emphasis on composite bridges. The temperature distribution in bridges depends primarily on the solar radiation, ambient air temperature and wind speed in the vicinity. Apart from data of the meteorological factors, good estimates of the thermal properties of material and the film coefficients are necessary for the prediction of temperature distribution. The design temperature profiles for various types of composite bridge deck with bituminous surfacing and concrete slab of different thicknesses are proposed. The factors affecting the design effective temperature are also reviewed and suitable values for Hong Kong are proposed. Results are compared with recommendations of the current local code. The method facilitates the development of site-specific temperature profiles for code documents, and it can also be applied to create zoning maps for temperature loading for large countries where there are great climatic differences.

• Structural Engineering and Mechanics
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• v.58 no.5
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• pp.799-823
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• 2016

A finite element model for the non-linear dynamic analysis of a reinforced concrete (RC) containment shell of a nuclear power plant subjected to extreme loads such as impact and earthquake is presented in this work. The impact is modeled by using an uncoupled approach in which a load function is applied at the impact zone. The earthquake load is modeled by prescribing ground accelerations at the base of the structure. The nuclear containment is discretized spatially by using 20-node brick finite elements. The concrete in compression is modeled by using a modified $Dr{\ddot{u}}cker$-Prager elasto-plastic constitutive law where strain rate effects are considered. Cracking of concrete is modeled by using a smeared cracking approach where the tension-stiffening effect is included via a strain-softening rule. A model based on fracture mechanics, using the concept of constant fracture energy release, is used to relate the strain softening effect to the element size in order to guaranty mesh independency in the numerical prediction. The reinforcing bars are represented by incorporated membrane elements with a von Mises elasto-plastic law. Two benchmarks are used to verify the numerical implementation of the present model. Results are presented graphically in terms of displacement histories and cracking patterns. Finally, the influence of the shear transfer model used for cracked concrete as well as the effect due to a base slab incorporation in the numerical modeling are analyzed.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.729-734
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• 2015

Improvement in the control strategy for continuous casting is a crucial requirement to enhance the slab's quality and to increase productivity. The mold oscillator adopts the dual cylinders due to its heavy weight, so the synchronized motion of two cylinders is an important aspect when precise control is needed. The conventional method uses the master-slave control applied to the valve input reference, but the synchronization performance should still be improved. This paper proposes a novel synchronization algorithm for dual cylinders used in a mold oscillator. The master-slave concept is applied to the target reference position, that is, the slave target reference position is controlled to match the slave cylinder's position with the master cylinder's position. In the simulation based on a Simulink model, the proposed algorithm shows a better synchronization performance in aspect of the mean of the absolute error and the peak synchronization error.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.709-712
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• 2015

This paper will introduce the development case study about virtual-reality-based operation training system for steel making process. Steel making process consist iron making process to create liquid steel, pig iron, by reduction process, steel making process to make molten steel by refining, continuous casting process to make slab, and rolling process to make final product like coil, plate. This steel making process deals with liquid and solid products, so facilities of steel making process are very various and complicated. In addition, according to various customer requirements, the recycle of facilities and recipes changing have been fast. So the training for skilled operators is very important point. In this paper, we develop steel making training system based virtual reality for training skilled operator. This system consists of virtual machine, virtual HMI, and virtual control panel. And for fitting the characteristics of each process and increasing the education effectiveness, we develop dynamic methods like the method of dynamic education system configuration, initial facilities setup operation education system, and etc.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 1992.11a
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• pp.91-101
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• 1992

The aim of this study is to offer the basic data concerning the architectural characteristics of the recently constructed farmhouses built by the residents’ self-planning after 1987, compared with the standard housing plan, for the desirable farmhouse planning. The 77 farmhouses, scattered in Milyang-gun, Yangsan-gun and Ulsan-gun near Ulsan city, were selected for the field measurement and the data, compared with the 14 standard housing plans, were analysed by the qualitative method. The farmhouses studied here showed average size of 25-pyongs(82.5m2) and took the flat slab type of roof by the masonry construction of the red blicks. The characteristics in planning were \circled1 the Anbang placed adjacent above the living room, \circled2 a pare of double-sliding doers for the Anbang. \circled3 a pare of double-sliding doors between the living room and the yard for the openness of the living room, \circled4 a door between the living room and the kitchen, \circled5 the multiuse-room by the kicthen for supplemental use, and \circled6 the storage space as attics secured indoor. The standard housing plans, different from these of the recently constructed farmhouses, placed emphasis on the separativeness of each space using the one hinged doors. The farmhouses built recently therefore were not affected by the characteristics of the standard housing plans.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.123-126
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• 2006

Existing Deck Plate for a one of system forms, there is various advantage and application actual results increasing rapidly. But design of deck is depending on engineering data collections or design data on deck manufacture ordinarily. When construct, is responsible for deflection occurrence, And Because confirmation of crack occurrence region is impossible, there is difficulty of repair, reinforcement about crack and water leakage. According to got following conclusion as result that economic performance, preservation administration and repair reinforcement develops easy using steel truss snap tie by wedge pin on coating plywood that is slab Panel Wood System Form method of construction there is Deck Plate's advantage. (1) In stab lower part is exposed disjointing in which a criminal is fastened to be interrogated after construction acceptance and repair, reinforcement of crack is possible (2) Construction cost curtailment effect of about 29.2% than conventional type and about 10% than deck plate (3) Construction period reduction of about 3 day than conventional type and about 0.3 day than deck plate (4) Labor curtailment effect more than about $29{\sim}50%$ from conventional type

• Steel and Composite Structures
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• v.11 no.1
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• pp.39-58
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• 2011

The subject of the ongoing research work is to analyze the composite action of the structural elements of composite slabs with profiled steel decking by experimental and numerical studies. The mechanical and frictional interlocks result in a complex behaviour and failure under horizontal shear action. This is why the design characteristics can be determined only by standardized experiments. The aim of the current research is to develop a computational method which can predict the behaviour of embossed mechanical bond under shear actions, in order to derive the design characteristics of composite slabs with profiled steel decking. In the first phase of the research a novel experimental analysis is completed on an individual concrete encased embossment of steel strip under shear action. The experimental behaviour modes and failure mechanisms are determined. In parallel with the tests a finite element model is developed to follow the ultimate behaviour of this type of embossment, assuming that the phenomenon is governed by the failure of the steel part. The model is verified and applied to analyse the effect of embossment's parameters on the behaviour. In the extended investigation different friction coefficients, plate thicknesses, heights and the size effects are studied. On the basis of the results the tendencies of the ultimate behaviour and resistance by the studied embossment's characteristics are concluded.

• Computers and Concrete
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• v.15 no.4
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• pp.503-514
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• 2015

Fibre-added concretes are frequently used in large site applications such as slab and airports as well as in bearing system elements or prefabricated elements. It is very difficult to determine the mechanical properties of the fibre-added concretes by experimental methods in situ. The purpose of this study is to develop an artificial neural network (ANN) model in order to predict the compressive and bending strengths of hybrid fibre-added and non-added concretes. The strengths have been predicted by means of the data that has been obtained from destructive (DT) and non-destructive tests (NDT) on the samples. NDTs are ultrasonic pulse velocity (UPV) and Rebound Hammer Tests (RH). 105 pieces of cylinder samples with a dimension of $150{\times}300mm$, 105 pieces of bending samples with a dimension of $100{\times}100{\times}400mm$ have been manufactured. The first set has been manufactured without fibre addition, the second set with the addition of %0.5 polypropylene and %0.5 steel fibre in terms of volume, and the third set with the addition of %0.5 polypropylene, %1 steel fibre. The water/cement (w/c) ratio of samples parametrically varies between 0.3-0.9. The experimentally measured compressive and bending strengths have been compared with predicted results by use of ANN method.

• Steel and Composite Structures
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• v.18 no.3
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• pp.565-582
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• 2015

This paper is concerned with the dynamic analysis of simply-supported steel-concrete composite beams under moving loads. Considering the interface slip between steel girder and concrete slab, the governing motion equations are derived from the direct balanced method. By variable separation approach, the analytical solution of natural frequencies and mode shapes are obtained, as well as the orthogonal conditions. Then the dynamic responses of the composite beam under moving loads are analyzed, and compared with the experimental results. The analysis results show that the governing motion equations become more complicated when interface slip is taken into account, and the dynamic behaviors are significantly influenced by the shear connection stiffness. In the dynamic calculation of composite beams, the global stiffness should not be reduced as the same factor to all orders, but as different ones according to the dynamic stiffness reduction factor (DSRF), to which should be paid more attention in calculation, design and experiment, or else great deviation is inevitable.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.397-400
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• 2006

Most of the civil structures in Korea and abroad have many kinds of damages when they are facing over-loaded traffics, long-term serviceability, and severe environmental conditions. Repair, rehabilitation, and retrofit are important for maintaining the serviceability of structures. In recent year, VES-LMC has been widely used as repair material for bridge deck repair and rehabilitation, because the VES-LMC has a various benefits such as traffic opening after 3 hours of curing, higher durability and bond strength. In case of any structure repaired or rehabilitated with VES-LMC, those were influenced capacity of bond between the base layer of slab and VES-LMC as well as physical properties of each other materials. The capacity of bond depended on purity of interface, micro cracks, curing of VES-LMC and so like. A kind of popular concrete repair technique, High pressure water jetting equipment is extremely efficient at removing damaged concrete. Removing damaged or poor quality concrete from sensitive structures such as bridge, tunnels, multi-story car parking decks and runways, using the high pressure water jetting could remove damaged or poor quality concrete remaining healthy and sound concrete. Accordingly, the purpose of this study is that it was to evaluate effect of hydrodemolition on the bond strength of VES-LMC overlay compared with effects of other method such as breaker, untreated. Also, it was evaluated the effect of surface moisture.