• Health Policy and Management
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• v.24 no.4
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• pp.380-388
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• 2014

Background: The volume of surgery has been examined as a major source of variation in outcome after surgery. This study investigated the direct effect of surgery volume to in hospitals mortality and the moderating effect of structural complexity-the level of diversity and sophistication of technology a hospital applied in patient care-to the volume outcome relationship. Methods: Discharge summary data of 11,827 cancer patients who underwent surgery and were discharged during a month period in 2010 and 2011 were analyzed. The analytic model included the independent variables such as surgery volume of a hospital, structural complexity measured by the number of diagnosis a hospital examined, and their interaction term. This study used a hierarchical logistic regression model to test for an association between hospital complexity and mortality rates and to test for the moderating effect in the volume outcome relationship. Results: As structural complexity increased the probability of in-hospital mortality after cancer surgery reduced. The interaction term between surgery volume and structural complexity was also statistically significant. The interaction effect was the strongest among the patients group who had surgery in low volume hospitals. Conclusion: The structural complexity and volume of surgery should be considered simultaneously in studying volume outcome relationship and in developing policies that aim to reduce mortality after cancer surgery.

• Structural Engineering and Mechanics
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• v.36 no.4
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• pp.513-527
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• 2010

This paper presents a three-dimensional finite element method based structural analysis model for structural analysis of reinforced concrete high-rise buildings during construction. The model considered the time-dependency of the structural configuration and material properties as well as the effect of the construction rate and shoring stiffness. Uniaxial compression tests of young concrete within 28 days of age were conducted to establish the time-dependent compressive stress-strain relationship of concrete, which was then used as input parameters to the structural analysis model. In-situ tests of a RC high-rise building were conducted, the results of which were used for model verification. Good agreement between the test results and model predictions was achieved. At the end, a parametric study was conducted using the verified model. The results indicated that the floor position and construction rate had significant effect on the shore load, whereas the influence of the shore removal timing and shore stiffness have much smaller. It was also found that the floors are more prone to cracking during construction than is ultimate bending failure.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.657-670
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• 2020

Due to the high compressive and tensile strength of ultra-high performance concrete (UHPC), UHPC used in steel concrete composite structures provided thinner concrete layer compared to ordinary concrete. This leaded to the headed stud shear connectors embedded in UHPC had a low aspect ratio. In order to systematic investigate the effect of headed stud with low aspect ratio on the structural behaviors of steel UHPC composite structure s this paper firstly carried out a test program consisted of twelve push out specimens. The effects of stud height, aspect ratio and reinforcement bars in UHPC on the structural behaviors of headed studs were investigated. The push out test results shows that the increasing of stud height did not obviously influence the structural behaviors of headed studs and the aspect ratio of 2.16 was proved enough to take full advantage of the headed stud strength. Based on the test results, the equation considering the contribution of weld collar was modified to predict the shear strength of headed stud embedded in UHPC. The modified equation could accurately predict the shear strength of headed stud by comparing with the experimental results. On the basis of push out test results, bending tests consisted of three steel UHPC composite slabs were conducted to investigate the effect of shear connection degree on the structural behaviors of composite slabs. The bending test results revealed that the shear connection degree had a significantly influence on the failure modes and ultimate resistance of composite slabs and composite slab with connection degree of 96% in s hear span exhibited a ductile failure accompanied by the tensile yield of steel plate and crushing of UHPC. Finally, analytical model based on the failure mode of composite slabs was proposed to predict the ultimate resistance of steel UHPC composite slabs with different shear connection degrees at the interface.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.59-64
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• 1989

On this condition of steel bridge member having a crack, occasionaly it is improssible to measure of stress history and to extract test specimen. Under this situation, tried to estimate remaining service life from statistical data on traffic and existing results of fatigue test without measuring of stress history and fatigue test. The main results are as following (1) Stress history of simple beam estimated from Montecallo simulation method with probabilistic model of traffic can be use to estimate remaining fatigue life instead of measuring of stress history. (2) In such a case measuring of remaining fatigue life at bridge member haying a crack, influences of RMS model and RMC model on fatigue crack growth rate are not differ without difference of applied stress range. (3) Application of cut off method may be overestimate remaining fatigue life.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.199-206
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• 2003

This paper presents the fatigue life of transverse joint of concrete pavement with the fatigue model test. A 1/12 scale model was used to satisfy the geometric load, material similitude, which are variables to the skew angel of transverse joint. From the test results by fatigue load 700kgf applied, we can have that the fatigue life of transverse joint with skew angle is better than that of transverse joint without skew angle. In addition, we can have that the fatigue life of skewed transverse joint with angle of 10 degree is better than that of skewed transverse joint with angle of 20 degree.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.57-60
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• 2011

Updating model parameters are required in order to simulate the actual behavior of the dynamic structure. A new strategy, mean-iterative neural networks (MINNs) has been proposed in this paper for model parameter updating of a steel box girder bridge. With new strategy for structural dynamic model updating, it offers many advantages such as potential savings of computational effort, more consistent in reaching convergence. The dynamic response obtained from the experimental test on a two span continuous bridge is used as the target for model updating. And the presented algorithm is applied to update the model parameters. These results show a good possible of using MINNs in practice for dynamic model updating.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.19-24
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• 2008

The thesis is for gust factor needing when calculate the wind resistance design. For the gust factor, to the membrane structural model, carry through the wind tunnel test and the static load test. Therefore, at first through the tensile test of the fabric material, designate the material of the membrane structural model. Then, to saddle, wave, arch and point four kinds of basic shape membrane structural models, carry on the wind tunnel test, determine their dynamic load and distortion on lateral direction. Finally, according to distort situation of the membrane structure in the wind tunnel test, carry on the static load experiment outside of the wind tunnel, calculate static load which corresponding with distort. According to dynamic load and the static load, figure out gust factor of these kinds of basic membrane structure.

• Structural Engineering and Mechanics
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• v.7 no.1
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• pp.69-80
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• 1999

The purpose of this study is to propose an analytical model for the simulation of the hysteretic behavior of RC (reinforced concrete) beam-column subassemblages under various loading histories. The discrete line element with inelastic rotational springs is adopted to model the different locations of the plastic hinging zone. The hysteresis model can be adopted for a dynamic two-dimensional inelastic analysis of RC frame structures. From the analysis of test results it is found that the stiffness deterioration caused by inelastic loading can be simulated with a function of basic pinching coefficients, ductility ratio and yield strength ratio of members. A new strength degradation coefficient is proposed to simulate the inelastic behavior of members as a function of the transverse steel spacing and section aspect ratio. The energy dissipation capacities calculated using the proposed model show a good agreement with test results within errors of 27%.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.6
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• pp.117-123
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• 2015

An experimental study of model truss-type vertical gate consisting of a truss and a plate was presented in this paper to examine the structural dynamics of the gates. A 1:61 scale model was constructed for the 95 m prototype gate using an acrylic truss and an acrylonitrile butadiene styrene plate. The scaled model was tested in a 1.6 m wide concrete flume for two orientations to determine the effects of gate orientation on structural vibrations. Natural frequencies of the model gate was measured and calibrated with FEM predictions. Vertical vibrations were measured under various operational conditions, including a range of bottom opening heights and different upstream and downstream water levels. The gate model with reverse direction was preferred due to its low overall vibrational response and flow level combinations. The test results also provide a basic dataset for development of operations guidelines that minimize flow-induced vibrations of the gates.

• Journal of the Korean Society of Safety
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• v.32 no.1
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• pp.66-74
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• 2017

Masonry walls which are commonly used for partitions in low-rise reinforced concrete (RC) structures, can be easily exposed to high risks under strong earthquakes. Since the strength degradations cannot be protected under the ground motions, their applications cannot be recommended for building structures which are designed to possess high seismic performances. However, masonry-infilled walls are typically considered as non-structural elements in evaluating the seismic performance of building structures. In order to figure out this problem, this study performed experiments using two specimens-only RC frame and RC frame infilled with masonry walls- under static loading. Also, the study established analytical models representing fully infilled frames and bare frame, and compared their structural behavior with test results. In addition, analytical model representing partially infilled frames was established and analyzed. Test results indicated that strength and energy dissipating capacity were increased for IW-RN(fully infilled frames) compared to the NW(bare frame). The nonlinear static analysis of the three specimens was also conducted using the inelastic plastic hinge frame element and diagonal strut models, and the analytical results successfully simulated the nonlinear behaviour of the specimens in accordance with the test results.