• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.59-65
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• 2002

EYM (European Yield Model), which was adopted in NDS (National Design Specification for wood construction), has been used in Korea without any verification of the analysis of bolted wood connections. In the case of applying lumber from domestic small diameter logs, however, there are some problems with the direct application of EYM ; 1) relatively low dowel bearing strength and dimensional stability due to a large amount of immature wood, 2) effect of MC (moisture contents) on the dowel bearing strength of wood and the yield load of a bolted connection. To evaluate the strength properties of bolted connections with lumber from domestic small diameter logs, effect of MC on the dowel bearing strength of wood was investigated and double shear bolted connection tests were performed. As the MC of wood increased, the dowel bearing strength was linearly reduced, even under 19% MC, which showed that adjustment, not considered in NDS, was required. Double shear bolted connection tests indicated that effect of MC on yield load should be considered in order to determine design value.

• Journal of the Korean Wood Science and Technology
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• v.50 no.4
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• pp.237-245
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• 2022

This study examined the structural performance of experimental parallel strand lumber (PSL) from a Larch veneer strand. The prototype of PSL from a Larch veneer strand was manufactured in the experimental laboratory and tested. The bending and dowel bearing strength were determined from the modulus of elasticity (MOE), modulus of rupture (MOR), and dowel bearing strength based on a 5% offset yield load. The test results indicated that the average MOR of PSL was higher than that of 2 × 4 dimension lumber, and the average MOE of PSL was lower than that of 2 × 4 dimension lumber. A linear relationship was observed between the MOR and MOE. The allowable bending stress of PSL was derived as specified in ASTM D2915 and compared with other research. The dowel bearing strength of PSL in parallel to the grain was approximately double that perpendicular to the grain of PSL. A comparison of several theoretical calculations based on each national code for the dowel bearing strength was conducted, and some theoretical equations produced results closer to the experimental results when it was parallel to the grain, but the difference was higher in the case perpendicular to the grain. The test results showed that PSL made with Japanese larch veneer strands appeared to be suitable for a raw material of structural composite lumber (SCL) appeared to be used as a raw material for SCL.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.59-64
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• 1994

Following the previous research(7), a total of forty six specimens were tested to scrutinize the dowel action of reinforcing bars. Concrete cover, width of specimen and reinforcing bar size were taken as main test variables for constant compressive strength of concrete, based on the observation of the test results, the characteristic effects of the test variables on the dowel strength have been analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.350-355
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• 1994

This study is aimed at the experimental investigation of the influence of the structural parameters such as concrete cover, width of specimen and bar size on the dowel action of reinforcing bari in high strength concrete members. Based on the proper combination of these parameter, a total of 46 specimens has been cast for fc'= 500 ㎏/㎠ and another 46 specimens for fc'= 700 ㎏/㎠, and cured at the laboratory. Comparative analyses have been made for the parametric contribution to the dowel strength from the test results, and a regress equation has been suggested.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.250-255
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• 1993

This research is aimed at the experimental investigation of the characteristic contribution of the structural parameters, such as concrete over, concrete strength and reinforcing bar size on the dowel strength of the reinforced concrete stuctures. A total of twenty four specimens were tested for eight experimental conditions. The test results showed relatively close agreements with the values calculated by Vintzeleou-tassios equation. From the observations of the test results, it was found that the concrete cover affected almost linearly on the dowel strength , while the var size and the concrete strength showed coupled effects.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2838-2843
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• 2011

Recently, the floating slab track that can effectively mitigate the vibration and structure-borne noise is being discussed to be adopted. The floating slab track which is a track system isolated from the sub-structure by vibration isolators. Unsimilarly to conventional track and the slab deflection is large. Therefore, the running safety and ride comfort should be investigated. Especially at slab joint since the load cannot be transferred, the possibility that the dynamic behavior of track and train became unstable is high. Thus, in general dowel bar are often installed at slab joints. To determine the appropriate dowel ratio the load transfer characteristics should be investigated. In this study, dowel bar joint is modeled by equivalent shear spring and this model is verified by comparison with experimental results. Using the proven model, the load transfer efficiency and deflection at slab joint according to dowel ratio, and stiffness and spacing of vibration isolator were examined.

• KCI Concrete Journal
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• v.12 no.1
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• pp.91-99
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• 2000

A new type of retrof=t anchor bolt that uses deformed reinforcing bars and a commercial adhesive was developed and then an experimental study was carried out to determine the behavior of the anchors in direct shear. The steel-to-concl몫ete interface was tested. Plain concrete slabs with about 20-MPa compressive strength were used for 23 direct shear tests performed Test variables were anchor diameters (D16, D22. and D29) and edge effect. Three different shear tests were completed: simple shear, edge shear where anchors were pulled against the concrete core, and edge shear where anchors were pushed against the concrete cover In the simple and the edge shear tests where the anchors were pulled against the core, the theoretical dowel strength determined by (equation omitted) was achieved but with relatively large displacements. The shear resistances increased with the increasing displacements. In the edge shear test where the anchors were pushrd against the cover, the peak shear strengths signif=cantly lower than the theoretical dowel strength were determined due to cracks developed in concrete when the edge distance was 80 mm. The peak strengths were about 50% of the dowel strength for Dl6 bar. and about 25% or less of the dowel strength for D22 and D29 bars. Test results revealed that the edge shear where the anchor was pushed against the cover controled.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.325-330
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• 2008

This study carried out the repeated freezing-thawing test in order to understand the long-term degradation mechanism of GFRP dowel bars. The mechanical property measured by shear test. In addition, analyzes repeated freezing-thawing degradation mechanism of GFRP dowel bars by observe the microstructure through Scanning Electron Microscope (SEM) and Gas Physisorption techniques. As the result of test, it was found that the mechanical property didn't decreased as the exposure time to water and repeated freezing-thawing environment. It shows clearly observed microstructure investigations.

• Computers and Concrete
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• v.14 no.4
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• pp.463-477
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• 2014

The modelling approach in the case of connections in precast buildings is specific. The assembly of the constitutive parts of the connection requires the inclusion of contact definitions in the model. In addition, the material non-linearity including the influence of the spatial stress distribution should be taken into account where appropriate. Here a complex model of a beam-to-column dowel connection is presented. Experiments on the analysed connection were performed within the framework of the European project SAFECAST (Performance of Innovative Mechanical Connections in Precast Building Structures under Seismic Conditions). Several material and interaction parameters were investigated and the influence of each of them was evaluated. The set of parameters which gave the best match with the experiments was chosen.

• Magazine of the Korea Concrete Institute
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• v.6 no.3
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• pp.215-220
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• 1994

Results of an experimental investigation on the bearing strength and stiffness of concrete under dowel bars are summarized. The effects of concrete strength bar diameter, and location of the bar on concrete were studied. Based on test results, empirical equations are proposed to predict the, concrete bearing strength and stiffness under reinforcing bars. Cornparisions of analytical arid experimental results are presented.