• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.47-53
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• 2014

The paper investigates the limit state of deflection for short and medium span steel girder bridges. Deflection depends on stiffness of steel girders and integrity of the reinforced concrete slab (composite action). Load and resistance parameters are treated as random variables. A probabilistic model is developed for prediction of the deflection. The structural performance can be affected by deterioration of components, in particular corrosion of steel girders. In addition, the creep of concrete can greatly influence the deflection of composite structures. Therefore, the statistical models for creep and corrosion of structural steel are incorporated in the model. Structures designed according to the AASHTO LRFD Code are considered. Load and resistance models are developed to account for time-variability of the parameters. Monte Carlo simulations are used to estimate the deflections and probabilities of serviceability failure. Different span lengths and girder spacing are considered for structures designed as moment-controlled and deflection-controlled. A summary of obtained results is presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.56-59
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• 2004

This paper presents the consideration of design guideline for underground HCS system, composite spancrete slab, under axial and bending force. Serviceability design requirements for continuous composite spancrete slab subjected axial force, which are allowable stress and deflection, are compared. Flexural strengths are evaluated by design guideline using strain-compatibility method. The results showed that stresses of spancrete and topping concrete, especially at the ends of beam, have much effect on design loads. Maximum service loads for tested specimens are proposed by allowable stress.

• Structural Engineering and Mechanics
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• v.49 no.4
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• pp.449-461
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• 2014

The use of low-ductility welded wire fabric (WWF) as a main tensile reinforcement in concrete slabs compromises the ductility of concrete structures. Lower ductility in concrete structures can lead to brittle and catastrophic failure of the structures. This paper presents the experimental study carried out on eight simply supported one-way slabs to study the structural behavior of concrete slabs reinforced with low-ductility WWF and steel fibers. The different types of steel fibers used were crimped fiber, hooked-end fiber and twincone fiber. The experimental results show that the ductility behavior of the slab specimens with low-ductility reinforcement was significantly improved with the inclusion of $40kg/m^3$ of twincone fiber. Distribution of cracks was prominent in the slabs with twincone fiber, which also indicates the better distribution of internal forces in these slabs. However, the slab reinforced only with low-ductility reinforcement failed catastrophically with a single minor crack and without appreciable deflection.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.174-177
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• 2000

In this paper, The bulging behavior of the solidified shell in continuously cast slabs have been numerically analyzed using three-dimensional elasto-plastic and creep finite element method Three-dimensional model has been applied in order to investigate the effect of the narrow face shell on restraining the bulging deflection. Solidification analysis are carried out by two-dimensional finite difference method. In this way, strains occurring at the solidification front near the narrow face of the slab, as well as those occurring in the board face have been computed. The adequacy of the model has been checked against the experimental results. In addition, the effect of the slab width and casting speed on the bulging are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.267-270
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• 2005

The section of double-tee is considered as one of the most efficient type for flexure. However, the depth of it is bigger then that of other slab systems. The story height of it is also increased because the duct space is required under the double tee in addition to their net depth. Thus, a new modified double-tees with the nib length of 1.58m was suggested in this study. The story height of this one is reduced up to 450mm by including duct space under the nib at the ends of slab. The four ends of the modified two single tees were designed by strut-tie models. Shear tests were performed on them to verify the safety. The ultimate shear strengths of non-prestressed two specimens were larger than the design shear strength by strut-tie models. They were failed in ductile with many distributed flexural crackings. However, the other prestressed two specimens showed much stiffer behaviors, less deflection. and strength than those of prestressed.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.385-390
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• 2003

As growing of industrialization and increasing of population, the quantities of waste glasses are rapidly growing in the earth. It cause some problems such as the waste of natural resources and environmental pollution. In this context, recycling waste glass as a material of concrete has a great advantage environmentally and economically. This study is aimed to investigate the effect of load and deflection on fiber reinforced concrete slab model utilizing waste glass by fine aggregates. The flexural strength of the concrete including waste glass increased considerably, as the inclusion rate of steel fiber were increased. And the first crack load, maximum load and energy absorption capacity increased remarkably as the inclusion rate of steel fiber were increased. Therefore, in this study we confirmed the possibility of application for the usage of waste glass to the steel fiber reinforced concrete.

• KCI Concrete Journal
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• v.12 no.2
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• pp.11-21
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• 2000

It is not easy to correctly predict deflections of reinforced concrete beams and one-way slabs due to the variability of parameters involved in the calculation of deflections. Monte Carlo simulation is used to assess the variability of deflections with known statistical data and probability distributions of variables. A deterministic deflection value is obtained using the layered beam model based on the finite element approach in which a finite element is divided into a number of layers over the depth. The model takes into account nonlinear effects such as cracking, creep and shrinkage. Statistical parameters were obtained from the literature. For the assessment of variability of deflections, 12 cases of one-way slabs and T-beams are designed on the basis of ultimate moment capacity. Several results of a probabilistic study are presented to indicate general trends indicated by results and demonstrate the effect of certain design parameters on the variability of deflections. From simulation results, the variability of deflections relies primarily on the ratio of applied moment to cracking moment and the corre-sponding reinforcement ratio.

• Structural Monitoring and Maintenance
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• v.6 no.4
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• pp.269-289
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• 2019

This study investigated experimentally the response of thick reinforced concrete specimens having hollow cores with critical parameters. The investigation includes testing of twelve specimens that are solid and hollow-core slab models. Each specimen consists of two pieces, the piece dimensions are (1.2 m) length, (0.3 m) width and (20 cm) thickness tested under both monotonic and repeated loading. The test program is carried out to study the effects of load type, core diameters, core shape, number of cores, and steel fiber existence. Load versus deflection at mid span, failure modes, and crack patterns were obtained during the test. The test results showed that core shape and core number has remarkable influenced on cracking pattern, ultimate load, and failure mode. Also, when considering repeated loading protocol, the ultimate load capacity, load at yielding, and ductility is reduced.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.394-399
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• 2005

Embedded rail track can be described as a track structure that is completely covered within pavement. Rail supported continually on a concrete slab or concrete plinth. There are many kinds of types such as non-resilient track and resilient track, super resilient embedded track (floating slab). Embedded rail track is generally the standard for light rail transit routes because this track has many advantages such as reducing noise, maintenance cost and weight of track. In this paper, decision of track profile is restricted by the optimum levels of the flangeway and the gap between the rail head and the pavement surface of depressing tread zone. By result of this study, embedded rail track can reduce corrosion of rail, internal stress and rail deflection.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.317-324
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• 2005

The specially orthotropic plate theory is used to analyse three-span continuous composite slab bridges with elastic intermediate supports. A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions, was developed and the result of application of this method to the three-span continuous composite slab bridges with elastic intermediate supports is presented. This type of bridge represents either concrete or sandwich type three-span bridge on polymeric supports for passive control or on actuators for active control. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. The finite difference method is used for this purpose in this paper. The influence of flexural stiffnesses and the modulus of the foundation are studied.