• Steel and Composite Structures
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• v.51 no.6
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• pp.647-659
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• 2024

Given the increased interest in enhancing structural sustainability, the current study sought to apply multiobjective optimization to a footbridge with a steel-concrete composite I-girder structure. It was considered as objectives minimizing the cost for building the structure, the environmental impact assessed by CO2 emissions, and the vertical accelerations created by human-induced vibrations, with the goal of ensuring pedestrian comfort. Spans ranging from 15 to 25 meters were investigated. The resistance of the slab's concrete, the thickness of the slab, the dimensions of the welded steel I-profile, and the composite beam interaction degree were all evaluated as design variables. The optimization problem was handled using the Multiobjective Harmony Search (MOHS) metaheuristic algorithm. The optimization results were used to generate a Pareto front for each span, allowing us to assess the correlations between different objectives. By evaluating the values of design variables in relation to different levels of pedestrian comfort, it was identified optimal values that can be employed as a starting point in predimensioning of the type of structure analyzed. Based on the findings analysis, it is possible to highlight the relationship between the structure's cost and CO2 emission objectives, indicating that cost-effective solutions are also environmentally efficient. Pedestrian comfort improvement is especially feasible in smaller spans and from a medium to a maximum level of comfort, but it becomes expensive for larger spans or for increasing comfort from minimum to medium level.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.2
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• pp.1-7
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• 2021

The concrete deck slab at the continuous span support of the steel box girder bridge is a structure that is combined with the upper flange. It is a structure that can cause tension cracks in the deck slab at the support causing problems such as durability degradation in long span bridges. This is because the tensile stress in the longitudinal direction of the slab exceeds the design tensile strength due to the effects of dead load and live load when applying a long span. Accordingly, it is necessary to control tensile cracking by adding a reinforcing bar in the axial direction to the slab at the support and to introduce additional compressive stress. To solve this problem, a structural system of a steel box girder bridge was proposed that introduces compressive stress as PS steel wire tension in the tensile stress section of the upper slab in the continuous support. The resulting structural performance was compared and verified through the finite element analysis and the steel wire tension test of the actual specimen. By introducing compressive stress that can control the tensile stress and cracking of the slab generated in the negative moment through the tension of the PS steel wire, it is possible to improve structural safety and strengthen durability compared to the existing steel box girder bridge.

• Structural Engineering and Mechanics
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• v.50 no.4
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• pp.501-524
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• 2014

This paper presents a type of composite box girder with corrugated webs and concrete filled steel tube slab to overcome cracking on the web and reduce self-weight. Utilizing corrugated steel web improves the efficiency of prestressing introduced into the top and bottom slabs due to the accordion effect. In order to understand the loading capacity of such new composite structure, experimental and numerical analyses were conducted. A full-scale model was loaded monotonically to investigate the deflection, strain distribution, loading capacity and stiffness during the whole process. The experimental results show that test specimen has enough loading capacity and ductility. Based on experimental works, a finite element (FE) model was established. The load-displacement curves and stress distribution predicted by FE model agree well with that obtained from experiments, which demonstrates the accuracy of proposed FE model. Moreover, simplified theoretical analysis was conducted depending on the assumptions which were confirmed by the experimental and numerical results. The simplified analysis results are identical with the tested and numerical results, which indicate that simplified analytical model can be used to predict the loading capacity of such composite girder accurately. All the findings of present study may provide reference for the application of such structure in bridge construction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.524-525
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• 2009

Heavy-weight impact noise(HN) is the most irritating noise in Korean apartment houses. It has been proclaimed standard floor system of 210mm thick slab with isolation material in the wall type structure. But this regulation is applied only new construction field and is not considered remodeling field. In general, the LN can be reduced by using isolation material but HN is known as relating with stiffness, strength & boundary condition of slab. Therefore it is difficulty in improving the HN on remodeling field. In this study, We conducted the reinforcement of concrete slab using C.F.S.(carbon fiber sheet), steel plate and steel beam after on-dol with isolation material on the remodeling field. As the test results, It appeared using C.F.S was no improved but using steel plate & steel beam were a little improved on HN.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.3
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• pp.215-220
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• 2006

Recently, steel-concrete composite slab decks have been widely used as highway bridge decks. In the construction of the composite slab decks, it is necessary to join two adjacent blocked bottom plates to form one unite in the longitudinal direction. In this paper, several types of longitudinal direction joints for Robinson type composite slab decks ared proposed herein and static bending test are carried out by using slab specimens. And the stress and deformation of the tensile grip connection with high strength bolts are discussed by using three-dimensional elastic-plastic FEM.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.91-101
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• 2004

This study sought to suggest a structural design guide and to investigate the structural performances of the new beam-slab system in order to decrease the height of floors in high-rise steel structure apartments. Experiments were performed to assess the capacity of the new beam-slab system in a steel structure with 9.8-m span, particulary structural material test, pure bending test of composite beam, three-point bending test of composite beam, and bending and shearing tests. Results showed that the suggested composite beam had stable structural behavior when stud connectors were located in the upper flange, and upper bars were calculated normally according to the design of the slab.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1659-1663
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• 2011

Precast concrete slab track is a track structure to be installed by transporting and assembling precast concrete slabs manufactured at the factory. This method can improve concrete quality, provide easy maintenance and reduce construction time, compared with in-situ concrete track. However, the concrete slabs being continuously connected in longitudinal direction, due to the temperature change between summer and winter, the openings at slab joints have occurred. Thus, in this study, to identify the cause of this opening of slab joint, the joint opening caused by temperature drop in the longitudinally continuous precast concrete slab track has been predicted using three-dimensional finite element analysis, and compared with field measurements. Based on the proven model, the slab joint opening, and the stress pattern of concrete slab and steel reinforcement according to concrete slab-base friction properties, concrete-reinforcement bond properties, and prestressing were analyzed.

• Journal of the Korean Society of Safety
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• v.21 no.6 s.78
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• pp.96-100
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• 2006

In this thesis, the crack investigation, the damage investigation, the drawing check, and the structural analysis were performed on a curved hollow RC(reinforced concrete) slab bridge structure to assess the structural safety of that. From the crack investigation result, main reason of crack occurrence is guessed with travelling of the large truck. Therefore reinforcement of slab structure is necessary by using the steel plate. When structural analysis, the straight beam model, the curved beam model, and the curved plate model is used. From the results of structural analysis for curved hollow RC slab bridge, the maximum bending moment and the maximum shear force was not a difference in each models. But the vertical displacement of mid span using the curved beam model was greater than that using the other models.

• Steel and Composite Structures
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• v.25 no.5
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• pp.523-534
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• 2017

Cable-supported ribbed beam composite slab structure (CBS) is proposed in this study. As a new cable-supported structure, it has many merits such as long span availability and cost-saving. Inspired by the previous research on cable-supported structures, the fabrication and construction process are developed. Pre-stress design method based on static equilibrium analysis is presented. In the algorithm, the iteration convergence can be accelerated and the calculation result can be kept in an acceptable precision by setting a rational threshold value. The accuracy of this method is also verified by experimental study on a 1:5 scaled model. Further, important parameters affecting the mechanical features of the CBS are discussed. The results indicate that the increases of sag-span ratio, depth of the ribbed beam and cable diameter can improve the mechanical behavior of the CBS by some extent, but the influence of strut sections on mechanical behavior of the CBS is negligible.

• Steel and Composite Structures
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• v.6 no.2
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• pp.123-138
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• 2006

This paper proposes a model for the analysis of the construction sequences of steel-concrete composite decks in which the slab is cast-in-situ for segments. The model accounts for early age shrinkage, such as thermal and endogenous shrinkage, drying shrinkage, tensile creep effects and the complex sequences of loading due to pouring of the different slab segments. The evolution of the structure is caught by suitably defining the constitutive relationships of the concrete and the steel reinforcements. The numerical solution is obtained by means of a step-by-step procedure and the finite element method. The proposed model is then applied to a composite deck in order to show its potential.