• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.165-168
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• 2003

The objective of this paper is to investigate the effective width of wide beam. Three specimens were designed to have different depths of wide beam and to simulate exterior beam-column joint including spandrel beam. Load reversals were applied to the end of wide beam to model behaviors under seismic situation. From the test, it was shown that the strength and effective width of specimens were improved when the depth of specimens increased. The effective width of wide beam depended on the depth of it. Formulas in ACI 318-02 underestimated the effective width of wide beam even though these reflected the contribution of the depth of beam.

• Structural Engineering and Mechanics
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• v.31 no.2
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• pp.225-235
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• 2009

The present paper reviews the shear design (of reinforced concrete beam) provisions of four different national codes and proposes a new but simplified shear strength empirical expression, incorporating variables such as compressive strength of concrete, percentage of longitudinal and vertical steel/s, depth of beam in terms of shear span-to-depth ratio, for reinforced concrete (RC) beams without shear reinforcement. The expression is based on the experimental investigation on RC beams without shear reinforcement. Further, the comparisons of shear design provisions of four National codes viz.: (i) IS 456-2000, (iii) BS 8110-1997, (iv) ACI 318-2002 (v) EuroCode-2-2002 and the proposed expression for the prediction of shear capacity of normal beam/s, have been made by solving a numerical example. The results of the numerical example worked out suggest that there is need for revision in the shear design procedure of different codes. Also, the proposed expression is less conservative among the IS, BS & Eurocode.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.125-130
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• 2001

A existing design method of PSC girder bridges, according to total service loads, stress required tendon force at a time. Because this design method increases beam depth, design of long span is difficult. However, As UC girder stressing at difficult loading stages reduces sectional depth of PSC girder, both design and operation of long span bridges is possible. so, this study analyzes the effect of design parameter (Girder Strength, Girder Spacing, Span Length, Joint Strength) on the beam depth of IPC girder continuous bridges, and shows sectional depth of UC girder for design of long span bridges. According to analysis, when a continuous bridges of same length span is at strength of joint over strength of girder of 600kg/$cm^{2}$, a change of beam depth is observed and when a continuous bridges of different span length is at strength of joint below strength of girder of 600kg/$cm^{2}$, a change of beam depth is observed. In two case, a change of beam depth is mostly observed over strength of girder of 350kg/$cm^{2}$ according to analysis of deflection data, a continuous bridges of IPC girder is nearly satisfied.

• Structural Engineering and Mechanics
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• v.85 no.1
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• pp.65-80
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• 2023

To explore the effect of Engineered Cementitious Composite (ECC) on improving the progressive collapse resistance of reinforced concrete frames under a middle column removal scenario, six beam-column substructures were tested by quasistatic vertical loading. Among the six specimens, four were ECC-concrete composite specimens consisting of different depth of ECC at the bottom or top of the beam and concrete in the rest of the beam, while the other two are ordinary reinforced concrete specimens with different concrete strength grades for comparison. The experimental results demonstrated that ECC-concrete composite specimens can improve the bearing capacity of a beam-column substructure at the stages of compressive arch action (CAA) and catenary action in comparison with ordinary concrete specimen. Under the same depth of ECC, the progressive collapse resistance of a specimen with ECC at the beam bottom was superior to that at the beam top. With the increase of the proportion of ECC arranged at the beam bottom, the bearing capacity of a composite substructure was increased, but the increase rate slows down with the proportion. Meanwhile, the nonlinear numerical analysis software MSC Marc was used to simulate the whole loading process of the six specimens. Theoretical formulas to calculate the capacities of ECC-concrete composite specimens at the stages of flexural action, CAA and catenary action are proposed. Based on the research results, this study suggests that ECC should be laid out at the beam bottom and the layout depth should be within 25% of the total beam depth.

• Structural Engineering and Mechanics
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• v.56 no.5
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• pp.797-811
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• 2015

An analytical-computational method along with finite element analysis (FEA) has been employed to analyse the dynamic behaviour of deteriorated structures excited by time- varying mass. The present analysis is focused on the comparative study of a double cracked beam with inclined edge cracks and transverse open cracks subjected to traversing mass. The assumed computational method applied is the fourth order Runge-Kutta method. The analysis of the structure has been carried out at constant transit mass and speed. The response of the structure is determined at different crack depth and crack inclination angles. The influence of the parameters like crack depth and crack inclination angles are investigated on the dynamic behaviour of the structure. The results obtained from the assumed computational method are compared with those of the FEA for validation and found good agreements with FEA.

• Radiation Oncology Journal
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• v.1 no.1
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• pp.29-36
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• 1983

The treatment of tumors along curved surfaces with stationary electron beams using cone collimation may lead to non-uniform dose distributions due to a varying air gap between the cone surface and patient. For large tumors, more than one port may have to be used in irradiation of the chest wall, often leading to regions of high or low dose at the junction of the adjacent ports. Electron-beam arc therapy may elimination many of these fixed port problems. When treating breast tumors with electrons, the energy of the internal mammary port is usually higher than that of the chest wall port. Bolus is used to increase the skin dose or limit the range of the electrons. We invertiaged the effect of various arc beam parameters in the isodose distributions, and combined into a single arc port for adjacent fixed ports of different electron beam eneries. The higher fixed port energy would be used as the arc beam energy while the beam penetration in the lower energy region would be controlled by a proper thickness of bolus. We obtained the results of following: 1. It is more uniform dose distribution of electron to use rotation than stationary irradiation. 2. Increasing isocenter depth on arc irradiation, increased depth of maximum dose, reduction in surface dose and an increasing penetration of the linear portion of the curve. 3. The deeper penetration of the depth dose curve and higher X-ray background for the smaller field sized. 4. If the isocenter depth increase, the field effect is small. 5. The decreasing arc beam penetration with decreasing isocenter depth and the isocenter depth effect appears at a greater depth as the energy increases. 6. The addition of bolus produces a shift in the penetration that is the same for all depths leaving the shape of the curves unchanged. 7. Lead strips 5 mm thick were placed at both ends of the arc to produce a rapid dose drop-off.

• Steel and Composite Structures
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• v.34 no.6
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• pp.819-835
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• 2020

The effects of atmospheric thermal loads on the response of structural elements that are exposed to open environments have been recognized by research works and design specifications. The main source of atmospheric heat is solar radiation, which dominates the variation of the temperature of air, earth surface and all exposed objects. The temperature distribution along the depth of steel members may differ with the geometry configuration, which means that the different-configuration steel members may suffer different thermally induced strains and stresses. In this research, an experimental steel beam was instrumented with many thermocouples in addition to other sensors. Surface temperatures, air temperature, solar radiation and wind speed measurements were recorded continuously for 21 summer days. Based on a finite element thermal analysis, which was verified using the experimental records, several parametric studies were directed to investigate the effect of the geometrical parameters of AISC standard steel sections on their thermal response. The results showed that the overall size of the beam, its depth and the thickness of its elements are of significant effect on vertical temperature distributions and temperature differences.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.214-215
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• 2002

Generally uniform dose distribution is assumed to be formed in a target region when a conventional dose formation method using a broad proton beam, a fixed modulation technique, a bolus and an aperture is employed. However, actual situations differ. We usually find non-uniformity in the target region. This is due to the insertion of a range-compensating bolus before the patient. Since the range-compensating bolus has an irregular shape, the scattering in the bolus depends on the lateral position. Dose distribution is overlapping results of dose distribution of pencil-proton beams traversing different lateral positions of the bolus. The lateral extent of dose distribution of each pencil beam traversing the different position differs each other at the same depth in the target object. This is a cause of the non-uniformity of the dose distribution. Therefore the same lateral extent of dose distribution should be attained for different pencil beams at the same depth to obtain a uniform dose distribution. For that purpose, we propose here a bi-material bolus. The bi-material bolus consists of a low-Z material determining mainly the range loss and a high-Z material defining mainly the scattering in the bolus. After passing through the bi-material bolus, protons traversing different lateral positions will have different residual range yet with the same lateral spread at a certain depth. Using the optimized bi-material bolus, we can obtain a more uniform dose distribution in the target region as expected.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.455-461
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• 1993

Experimental measurements of dose characteristics with pentagonal applicator at nominal energy of 4, 6, 9, 12 and 15 MeV electron beam were performed for intraoperative radiotherapy (IORT) in ML-15MDX linear accelerator. This paper presents the percent depth dose, surface dose, beam flatness and output factors of using the IORT applicator in different electron beam energy. The output factor showed as a 24 percent higher in IORT applicator than that of reference $10{\times}10cm^2$ applicator. The surface dose of using the IORT applicator showed 7.7 and 2.7 percent higher than that of reference field in 4 and 15 MeV electron beam, respectively. In our experiments, the variation of percent depth dose was very small but the output factor and flatnees at 0.5 cm depth have showed a large value in IORT applicator.

• Steel and Composite Structures
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• v.16 no.5
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• pp.507-519
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• 2014

In this paper, a higher order shear deformation beam theory is developed for static and free vibration analysis of functionally graded beams. The theory account for higher-order variation of transverse shear strain through the depth of the beam and satisfies the zero traction boundary conditions on the surfaces of the beam without using shear correction factors. The material properties of the functionally graded beam are assumed to vary according to power law distribution of the volume fraction of the constituents. Based on the present higher-order shear deformation beam theory, the equations of motion are derived from Hamilton's principle. Navier type solution method was used to obtain frequencies. Different higher order shear deformation theories and classical beam theories were used in the analysis. A static and free vibration frequency is given for different material properties. The accuracy of the present solutions is verified by comparing the obtained results with the existing solutions.