• 한국농공학회논문집
• /
• 제64권4호
• /
• pp.45-53
• /
• 2022

In this study, the loading test and structural analysis were performed on the snow load and the results were compared. The load plates were loaded on the roof surface of the model, and structural analysis was performed under the same conditions. The result of loading test, the maximum displacement was observed in the center of the top, and the maximum stress was observed near the bottom point. Displacement and stress were found to have a high linear relationship with the load. Comparing the structural analysis results with the loading test results, the maximum displacement difference is 4.5% and the maximum stress difference is 10.2%. It is expected that closer results can be derived if the boundary conditions for the longitudinal direction of the model are clarified during experiments and analysis.

• 한국물환경학회지
• /
• 제26권1호
• /
• pp.111-115
• /
• 2010

Beaches in estuaries, bays, and harbors are frequently contaminated with indicators of human pathogens such as fecal indicator bacteria. Tracking down the sources of contamination at these enclosed beaches is complicated by the many point and non-point sources that could potentially degrade water quality along the shore. A mathematical framework was developed to test quantitative relationships between fecal indicator bacteria concentration in ankle depth water at enclosed beaches, the loading rate of fecal indicator bacteria from non-point sources located along the shore, physical characteristics of the beach that affect the transport of fecal indicator bacteria across the beach boundary layer, and a background concentration of fecal indicator bacteria attributable to point sources of fecal pollution that impact water quality over a large region of the embayment. Field measurements of fecal indicator bacteria concentrations and water turbulence at an enclosed beach were generally consistent with predictions and assumptions of the mathematical model, and demonstrated its utility for assessing waste load of non-point sources, such as runoff, bather shedding, bird droppings, and tidal washing of contaminated sediments.

• Structural Engineering and Mechanics
• /
• 제91권4호
• /
• pp.335-347
• /
• 2024

This paper presents the behavior of geopolymer concrete beams reinforced with glass fiber reinforced polymer (GFRP) bars. In the study, ordinary Portland cement concrete and geopolymer concrete beams having GFRP bars were prepared and tested under four-point loading. The load-deflection diagrams and load capacities of the tested beams were obtained. It was observed that the tested beams exhibited good ductility and significant deflection capacity. The results showed that increasing the tension GFRP reinforcement ratio caused enhancement in the strength capacity of geopolymer concrete beams. In addition, the tested beams were analyzed to obtain the load capacity and the load-deflection responses. The theoretical load-deflection curves and load bearing capacities have been predicted well with the test results. Parametric study has been performed to determine the influences of concrete strength, shear span to depth ratio (a/d) and reinforcement ratio on the behavior of geopolymer concrete beams longitudinally reinforced with GFRP bars. It was concluded that increasing concrete strength led to an increase in load capacity. Besides, the ultimate load increased as the reinforcement ratio increased. On the other hand, increasing a/d ratio reduced the ultimate load value of GFRP reinforced geopolymer concrete beams.

• 한국전문물리치료학회지
• /
• 제7권2호
• /
• pp.20-34
• /
• 2000

The purpose of this study was to establish modified physiological cost index (PCI) for predicting energy consumption by heart rate (HR) at isokinetic ergometer exercise testing. The subjects were twenty-eight healthy men in their twenties. All of them performed upper and lower extremity isokinetic ergometer exercise tests which had six loads (400, 500, 600, 700, 800, and 900 kg-m/min) and five loads (400, 500, 600, 700, and 800 kg-m/min) respectively. The exercise sessions were finished when HR was in plateau. HR and oxygen consumption were determined during the final minute. Resting heart rate and oxygen consumption were used for calculating heart rate, oxygen consumption changes and modified PCI. Regression analysis established the relationship between each variable to work load, HR and oxygen consumption. The results were as follows: 1) In the lower extremity ergometer exercise test, oxygen consumption increased continuously as work load increased, but in the upper extremity ergometer test, oxygen consumption only increased until work load was 700 kg-m/min. 2) HR increased as work load increased in both exercise tests, but in the upper extremity ergometer test, HR decreased from the 700 kg-m/min. 3) The modified PCI increased as work load mcreased until the 700 kg-m/min point in the lower extremity ergometer test and until the 500 kg-m/min point in the upper extremity ergometer test when it started to decrease in both tests. 4) In the lower extremity ergometer exercise test, regression analysis established the relation as $dVO_2$ = -.0215HR - .2141 where $dVO_2$ is given in l/min and HR in beat/min ($R^2$ = .2677, p = .000). ln the upper extremity ergometer exercise test. regression analysis established the relation as $dVO_2$ = -.0115HR + .2746 ($R^2$ = .1308, p = .000). The results of this study were similar to previous studies but were different under high work load conditions. So modified PCI should be used with only low intensity work load testing. Subjects for upper extremity ergometer exercise testing should complete a prescribed training course prior to testing, and only low intensity work load should be used for safety considerations.

• Advances in concrete construction
• /
• 제3권4호
• /
• pp.269-282
• /
• 2015

In this paper, a compression to tensile load converter device was developed to determine the anisotropic tensile strength of concrete. The samples were made from a mixture of water, fine sand and cement, respectively. Concrete samples with a hole at its center was prepared and subjected to tensile loading using the compression to tensile load converter device. A hydraulic load cell applied compressive loading to converter device with a constant pressure of 0.02 MPa per second. Compressive loading was converted to tensile stress on the sample because of the overall test design. The samples have three different configurations related to loading axis; 0, $45^{\circ}$, $-45^{\circ}$. A series of finite element analysis were done to analyze the effect of hole diameter on stress concentration of the hole side along its horizontal axis to provide a suitable criterion for determining the real tensile strength of concrete. Concurrent with indirect tensile test, Brazilian test and three point loading test were also performed to compare the results from the three methods. Results obtained by this device were quite encouraging and show that the tensile strengths of concrete were similar in different directions because of the homogeneity of bonding between the concrete materials. Also, the indirect tensile strength was clearly lower than the Brazilian test strength and three point loading test.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.397-402
• /
• 2003

Fracture resistance curves for concerned materials are required in order to perform elastic-plastic fracture mechanical analyses. Fracture resistance curve is built with J-integral values and crack extension values. The objective of this paper is to apply the load ratio method to the measurement of the crack length for the real scale pipe specimen. For these, the fracture test using the real scale pipe specimen and finite element analyses were performed. A 4-point bending jig was manufactured for the pipe test and the direct current potential drop method and the load ratio method was used to measure the crack extension and the length for the real scale pipe test. Finite element analyses about the compliance of the pipe specimen were executed for applying the load ratio method according to the crack length.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.986-995
• /
• 2008

This study introduces the testing results of the AL car body which is applied to LRT. The LRT car body is made of aluminum structure materials like a sandwich panel. The static load test was performed to evaluate the structural characteristic and stability of the AL car body. Considering the vertical, compressive, twisting load and 3-point supporting, Bend natural frequency Measurement, Twist natural frequency Measurement type as a testing terms, the structural stability of a car body was evaluated.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1604-1612
• /
• 2009

This study introduces comparison the testing results of the AL car body which is applied to FSW and GMAW welding method. The car body is made of aluminum structure materials like a sandwich panel. The static load test was performed to evaluate the structural characteristic and stability of the AL car body. Considering the vertical, compressive, twisting load and 3-point supporting, Bend natural frequency Measurement, Twist natural frequency Measurement type as a testing terms, the structural stability of a car body was evaluated.

• Structural Engineering and Mechanics
• /
• 제71권1호
• /
• pp.13-22
• /
• 2019

In this paper, the static and dynamic responses of a tied-arch railway bridge under train load were studied through field tests. The deflection and stresses of the bridge were measured in different static loading scenarios. The dynamic load test of the bridge was carried out under the excitation of running train at different speeds. The dynamic properties of the bridge were investigated in terms of the free vibration characteristics, dynamic coefficients, accelerations, displacements and derailment coefficients. The results indicate that the tie of the measuring point has a significant effect on the vertical movement of the test section. The dynamic responses of arch bridge are insensitive to the number of trains. The derailment coefficients of locomotive and carriage increase with the train speed and symmetrically distributed double-line loads reduce the train derailment probability.

• 한국물환경학회지
• /
• 제25권5호
• /
• pp.792-802
• /
• 2009

The objective of this study is to construct the watershed management system with link of the non-point sources model and to estimate delivery ratio duration curves for various pollutants. For the total water pollution load management system, non-point source model should be performed with the study of the characteristic about non-point sources and loadings of non-point source and the allotment of pollutant in each area. In this study, daily flow rates and delivered pollutant loads of Nakdong river basin are simulated with modified TANK model and minimum variance unbiased estimator and SWAT model. Based on the simulation results, flow duration curves, load duration curves, and delivery ratio duration curves have been established. Then GIS analysis is performed to obtain several hydrological geomorphic characteristics such as watershed area, stream length, watershed slope and runoff curve number. As a result, the SWAT simulation results show good agreements in terms of discharge, BOD, TN, TP but for more exact simulation should be kept studying about variables and parameters which are needed for simulation. And as a result of the characteristic discharges, pollutants loading with the runoff and delivery ratios, non-point sources effects were higher than point sources effects in the small-scale test bed of Nakdong river basin.