• Computers and Concrete
• /
• v.1 no.3
• /
• pp.325-354
• /
• 2004

Slabs in buildings and bridge decks, which are restrained against lateral displacements at the edges, have ultimate strengths far in excess of those predicted by analytical methods based on yield line theory. The increase in strength has been attributed to membrane action, which is due to the in-plane forces developed at the supports. The benefits of compressive membrane action are usually not taken into account in currently available design methods developed based on plastic flow theories assuming concrete to be a rigid-plastic material. By extending the existing knowledge of compressive membrane action, it is possible to design slabs in building and bridge structures economically with less than normal reinforcement. Recent research on building and bridge structures reflects the importance of membrane action in design. This paper describes the finite element modelling of membrane action in reinforced concrete slabs through optimisation of a simple concrete model. Through a series of parametric studies using the simple concrete model in the finite element simulation of eight fully clamped concrete slabs with significant membrane action, a set of fixed numerical model parameter values is identified and computational conditions established, which would guarantee reliable strength prediction of arbitrary slabs. The reliability of the identified values to simulate membrane action (for prediction purposes) is further verified by the direct simulation of 42 other slabs, which gave an average value of 0.9698 for the ratio of experimental to predicted strengths and a standard deviation of 0.117. A 'deflection factor' is also established for the slabs, relating the predicted peak deflection to experimental values, which, (for the same level of fixity at the supports), can be used for accurate displacement determination. The proposed optimised concrete model and finite element procedure can be used as a tool to simulate membrane action in slabs in building and bridge structures having variable support and loading conditions including fire. Other practical applications of the developed finite element procedure and design process are also discussed.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1370-1378
• /
• 2007

High speed railway bridge is affected on safety of bridge by dynamic amplification effect, when dynamic response of bridge is equal to effect cycle load for rolling stock axle according to high speed operation train. And excessive deformation of structure has negative effect on operation safety of train and comfort of passenger due to fluctuation of wheel load by torsion of track etc. and decrease of contact force on vehicle wheel-rail. To ensure the safety of track and train operation safety, it is have to perform the study on resonance and deformation of structure. That criteria and requirement of railway bridge is limitation of vertical acceleration on deck for dynamic behavior of structure, contact of vehicle wheel and rail, limitation of face distortion and rotation angle of end deck, and limitation of vertical displacement by train. Unlike KYEONGBU High Speed Railway, New constructed HONAM High Speed Railway have to applied the new requirement for dynamic behavior safety according to change of condition which is type of ballast (slab ballast), interval of track, and actual rolling stock load. Therefore, in this paper, it was conformed the dynamic characteristic due to parameter, which related with above mentioned criteria, for steel composite bridges.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.19 no.1 s.71
• /
• pp.15-25
• /
• 2006

The researches on the early-aged concrete hydration process and the techniques for the early-aged concrete crack control mainly have been focused and developed on the massive concretes in both experimental and numerical studies. However, those researches for relatively thin members such as the upper slab of the reinforced concrete rahmen bridge have nearly been attempted. In this study, a designing technique for crack controlling in the thin members of the early-aged reinforced concrete rahmen bridges based on measured temperature history, strength revelation model and sinkage model is proposed. A method of calculating the reinforcing bar area for crack controlling is also proposed and it is found that the distributing bars under the design loads become the main reinforcing bars in the temperature stress analysis of the early-aged reinforced concrete rahmen bridges. It is shown that the proposed analysis technique is able to use the design of crack control for the early-aged reinforced concrete rahmen bridge.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.2
• /
• pp.43-50
• /
• 2018

In this study, to investigate the shear connection material for the composite of steel plate and bottom plate, design standards and research cases for shear connectors in various countries around the world were analyzed and shear tests were performed on the Push-out specimens with a shear connection, which transmits the horizontal shear force developed on the contact surface between the steel plate and the concrete slab due to various vertical loads acting on the bridge deck. Through Push-out tests of shear studs, of which FRP bar instead reinforcement is placed, the shear stud evaluation formula of the steel strap bottom plate was suggested. The suggested equation suggested in this study has the safety factor of approximately three times compared to allowable strength of highway bridge design criteria. In addition, compared to existing DIN standards and Viest assessment equation, the results showed similar values(approximately, 5% error).

• Journal of the Korea Concrete Institute
• /
• v.26 no.1
• /
• pp.3-12
• /
• 2014

Hybrid Truss Bridge (HTB) uses steel truss webs instead of concrete webs in prestressed box girder bridges, which is becoming popular due to its structural benefits such as relatively light self-weight and good aesthetics appearance. Since the core technology of this bridge is the connection system between concrete slabs and steel truss members, several connection systems were proposed and experimentally evaluated. Also, the selected joint system was applied to the real bride design and construction. The research was performed on the connection system, since it can affect the global behavior of this bridge such as flexural and fatigue behaviors as well as the local behavior around the connection region. The evaluation study showed that HTB applied to a curved bridge or an eccentrically loaded bridge had a weak torsional capacity compared to an ordinary PSC box girder bridge due to the open cross-sectional characteristic of HTB. Therefore, three types of girders with different joint system between truss web member and concrete slab were tested for their torsional capacity. In this study, the three different types of HTB girders under torsional loading were simulated using FEM analysis to investigate the torsional behavior of HTB girders more in detail. The results are discussed in detail in the paper.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.3
• /
• pp.96-103
• /
• 2018

An analysis using a statistical method is generally used to determine the effective temperature based on the temperature design load of a bridge. In this study, the effective temperature was calculated by building an artificial neural network (ANN) capable of improving the statistical method. A Steel box girder bridge specimen was made with a width of 2.0 m, height of 2.0 m, and length of 3.0 m and 0.2 m the upper slab. Twenty one temperature gauges were attached to measure the temperature between 2014 and 2016 for three years. An ANN was learned using the data measured from 2014~2015 and the results were compared with the Euro codes. The error rate between the Euro code and statistical analysis values was analyzed to be 4.1 % for the total measurement point. The ANN was verified and the effective bridge temperatures were calculated using the temperature data measured in 2016. The results revealed an approximate 3.97 % difference from the statistical analysis values. This degree of error is considered to be acceptable in terms of engineering for the analysis of an ANN. An ANN can easily predict the effective temperature of a bridge by knowing the input values of the region's highest temperature, bridge type, and upper asphalt thickness when designing the bridge's temperature loads.

• Resources Recycling
• /
• v.22 no.2
• /
• pp.62-70
• /
• 2013

Electric arc furnace slag is made in ironworks during steel refining, it is been increasing chemical and physical resistibility using ageing method of unstable state of melting steel slag for using concrete's fine aggregates. Which is been changing stable molecular structure of aggregates, it restrains moving of ion and molecule. In Korea, KS F 4571 has been prepared for using the electric arc furnace slag to concrete aggregates. In this study, Electric arc furnace slag is used in the PMC(Polymer Modified Concrete) which is applied a bridge pavement of rehabilitation, largely. In that case, this study evaluates the structural safety about increasing the specific weight. The 4-type bridges(RC slab bridge, RC rigid-frame bridge, PSC Beam bridge, Steel box girder bridge) pavement's increasing the total dead load is in 1 ~ 2%. Design moments in a load combination are increased less then 2%. safety factor is decreased less than 3%. Therefore, the structural safety has no problem for applying the electric arc furnace slag within PMC in bridge.

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.6
• /
• pp.515-527
• /
• 2013

Building energy simulations which are mainly used in Korea have evaluated the building energy performance with the different thermal conductivity of construction materials. In order to evaluate the energy consumption accurately, the difference in thermal conductivity of the wood used in stud for wooden structure was confirmed from the each simulation. In addition, the thermal transmission of building members and the thermal bridge at the conjunction of building members according to thermal conductivity from each simulation programs were researched. The thermal conductivity of pine that has the largest variation among the energy simulations was applied to the thermal properties of studs in wooden structure. The maximum error between the maximum and minimum thermal transmission of roof, wall, and floor slab was $0.023W/m^2{\cdot}K$. Plus, that thermal bridge at Rafter junction on the roof, roof-wall joint, and floor slab-wall joint was $0.025W/m{\cdot}K$. The heat transfer image for changes in temperature and the heat exchange were analyzed by HEAT2 program. The distorted temperature lines were found around the insufficient insulated connection parts. It was predicted that the temperature at the distorted parts in the analyzed image was lower than that of the other portion of the other structures.

• Magazine of the Korea Concrete Institute
• /
• v.6 no.6
• /
• pp.143-150
• /
• 1994

Most widened bridges have been constructed by the joining-construction method that makes new and existmg bridges structurally a single structure. Since the joining-constructiori method has several problems in design and construction viewpoint, this study is conducted in order to investigate the flexural fatigue behavior of RC slabs, which are widened and influenced by traffic-induced vibration of existmg bridge during placing and curing of new concrete, with the prototype fatigue test. It was found that stress concentration at the jclmts anti slips between steel bar and concrete are occured. Hut, the general tx:havinrs are similar to the original state and joining-construction method using expansive concrete nut~gated the influence of the trafflc-induced vibration.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.373-378
• /
• 2002

The waterproofing system's performance is known to show a determining by complex interaction of material factors, design details, and the qualify of construction, and the waterproofing integrity of waterproofing membranes is determined by the bond to the deck and the amount of damage to the waterproofing membrane. In this research, the basic properties of waterproofing membranes on market and the tensile adhesive characteristics of waterproofing systems of concrete bridge deck have also been investigated in the view of the damages frequently reported from job site. As a results of tensile adhesive strength of waterproofing system, tensile strength is decrease with surface moisture contents except for inorganic-elastomeric liquid waterproofing membrane, and increase with strength of deck slab. Also tensile adhesive strength is generally increase in case of moisture curing of specimen because of pore structure and surface leveling. The after asphalt concrete paving tends to increase more than before those. The results of the liquid waterproofing membranes are upside-down, and the more concrete has strength, the more strength of tensile adhesive increase. The ambient temperature and the rolling temperature of asphalt concrete when application of the waterproofing membrane has considerable influence on the performance of waterproofing system.