• 한국안전학회지
• /
• 제22권6호
• /
• pp.55-62
• /
• 2007

The structural safety of long span bridges such as suspension bridges is smaller under the construction stage than in the completion. But the importance of construction sequences has been neglected in most of safety check programs. On this study is developed the structural analysis method of suspension bridges considering construction sequences and structural analyses are performed by step by step during construction. This can be used to determine the safest erection method. The results shows that the more critical structural behavior appears under construction than after completion.

• Nuclear Engineering and Technology
• /
• 제38권3호
• /
• pp.277-284
• /
• 2006

In order to ensure the structural integrity of nuclear welded structures during design life, the fatigue life has to be evaluated by fatigue analysis procedures presented in technical codes such as ASME B&PV Code Section III. However, existing fatigue analysis procedures do not explicitly consider the presence of welded joints. A new fatigue analysis procedure based on a structural stress/fracture mechanics approach has been recently developed in order to reduce conservatism by erasing uncertainty in the analysis procedure. A recent review of fatigue crack growth data under various mean loading conditions using the structural stress/fracture mechanics approach, does not consider the mean loading effect, revealed some significant discrepancies in fatigue crack growth curves according to the mean loading conditions. In this paper, we propose the use of the stress intensity factor range ${\Delta}K$ characterized with loading ratio R effects in terms of the structural stress. We demonstrate the effectiveness in characterizing fatigue crack growth and S-N behavior using the well-known data. It was identified that the S-N data under high mean loading could be consolidated in a master S-N curve for welded joints.

• Earthquakes and Structures
• /
• 제14권6호
• /
• pp.493-503
• /
• 2018

With the further increase of span length, the cable-stayed bridge tends to be more slender, and becomes more susceptible to the seismic action. By taking a super long-span cable-stayed bridge with main span of 1400m as example, structural response of the bridge under the E1 horizontal and vertical seismic excitations is investigated numerically by the multimode seismic response spectrum and time-history analysis respectively, the seismic behavior and also the effect of structural nonlinearity on the seismic response of super long-span cable-stayed bridge are revealed. Furthermore, the effect of structural parameters including the girder depth and width, the tower structural style, the tower height-to-span ratio, the side-tomain span ratio, the auxiliary piers in side spans and the anchorage system of stay cables etc on the seismic performance of super long-span cable-stayed bridge is investigated numerically by the multimode seismic response spectrum analysis, and the favorable earthquake-resistant structural system of super long-span cable-stayed bridge is proposed.

• 한국지진공학회논문집
• /
• 제26권5호
• /
• pp.203-209
• /
• 2022

A simplified method for earthquake response analysis of a rectangular liquid storage tank is proposed with fluid-structure interaction considered. In order to simplify the complex three-dimensional structural behavior of a rectangular liquid storage tank, it is assumed that structural deformation does not occur in the plane parallel to the direction in which the earthquake ground motion is applied but in the plane perpendicular to the direction. The structural deformation is approximated by combining the natural modes of the simple beam and the cantilever beam. The hydrodynamic pressure, the structure's mass and stiffness, and the hydrodynamic pressure's added mass are derived by applying the Rayleigh-Ritz method. The natural frequency, structural deformation, pressure, effective mode mass, and effective mode height of the rectangular liquid storage tank are obtained. The structural displacement, hydrodynamic pressure, base shear, and overturning moment are calculated. The seismic response analysis of an example rectangular liquid storage tank is performed using the proposed simplified approach, and its accuracy is verified by comparing the results with the reference solution by the finite element method. Existing seismic design codes based on the hydrodynamic pressure in rigid liquid storage tanks are observed to produce results with significant errors that cannot be ignored.

• 한국조리학회지
• /
• 제22권6호
• /
• pp.120-131
• /
• 2016

The purpose of this study was to examine the structural relationship between customers' perception of authenticity, justice, customer commitment, and customer behavior in franchise coffee shops. To test the hypotheses of the study, a total of 428 customers in Korea were considered in an empirical analysis using a two-step structural equation model (SEM) approach. In particular, employees' authenticity had relatively great influence on customers' continuous and affective commitment and their justice had greater influence on customers' normative commitment. Also, customers' continuous commitment, normative commitment, and affective commitment significantly influence customer participation behavior, while normative commitment and affective commitment have a significant effect customer citizenship behavior. Research thus far divided justice and authenticity into separate concepts and examined relation with customer commitment or behaviors but the present study put cognitive process of justice and emotional process of authenticity on the same line and evaluated their different influence on customer commitment and behaviors, thereby verifying that not justice perceived by customers induced desirable customer behaviors but authenticity they felt with their heart played a more superior role in customer commitment or behaviors. This means that authentic services rather than justice induce customers' positive behaviors.

• 대한간호학회지
• /
• 제44권2호
• /
• pp.119-128
• /
• 2014

Purpose: This study is an examination of the paths in which the primary factors of anxiety, impulsiveness, knowledge of life safety practice, attitudes towards life safety practice, interpersonal support, and self-efficacy from Pender's Health Promotion Model influence the practice of life safety behavior in school-age children. Methods: The sample consisted of 489 5th and 6th grade students recruited from five elementary schools in Seoul City and four provinces, South Korea. Data were analyzed using descriptive statistics, correlations, factor analysis, and structural equation modeling. Results: Attitudes towards life safety practice, interpersonal support, self-efficacy and impulsiveness directly influenced practice of life safety behavior. Anxiety did not have a direct influence on practice of life safety behavior, but indirectly affected it. In this modified model, 52.0% of the practice of life safety behavior was explained by the primary factors. Conclusion: To facilitate the practice life safety behaviors in late childhood, a positive attitude towards life safety needs to be developed along with decreasing impulsiveness and enhancing self-efficacy.

• 한국구조물진단유지관리공학회 논문집
• /
• 제6권4호
• /
• pp.139-146
• /
• 2002

A analysis of crack behavior in RC member was performed by nonlinear finite element method. Two crack models were used in F.E.M.(finite element method): one was FCM (the fixed crack model) and the other was RCM (the rotated crack model). Based on parametric study, the ratio of shear steel, strength of concrete, and a/d(shear span/effective depth) were compared with test results of references. According to the test results, when the member behavior was affected by the shear or diagonal tension, RCM was reasonable. However, when the behavior was affected by the flexibility, FCM was more appropriate. In addition, each crack model behavior for the change of shear steel ratio, the increase of strain energy was constant in FCM, but it was different in RCM because of diagonal crack distribution and crack width. Since the strength of concrete is affected not only by shear but also by flexural strength, each crack model behavior yields similar results.

• 한국항공운항학회지
• /
• 제18권4호
• /
• pp.44-50
• /
• 2010

Structural vibration is a significant problem in many multi-part or multi-component assemblies. In aircraft industry, structures are composed of various fasteners, such as bolts, snap, hinge, weld or other fastener or connector (collectively "fasteners"). Due to these, prediction and design involving dynamic characteristics is quite complicated. However, the current state of the art does not provide an analytical tool to effectively predict structure's dynamic characteristics, because consideration of structural uncertainties (i.e. material properties, geometric tolerance, dimensional tolerance, environment and so on) is difficult and very small fasteners in the structure cause a huge amount of analysis time to predict dynamic characteristics using the FEM (finite element method). In this study, to resolve the current state of the art, a new approach is proposed using the FEM and probabilistic analysis. Firstly, equivalent elements are developed using simple element (e.g. bar, beam, mass) to replace fasteners' finite element model. Developed equivalent elements enable to explain static behavior and dynamic behavior of the structure. Secondly, probabilistic analysis is applied to evaluate the PDF (probability density function) of dynamic characteristics due to tolerance, material properties and so on. MCS (Monte-Carlo simulation) is employed for this. Proposed methodology offers efficiency of dynamic analysis and reality of the field as well. Simple plates joined by fasteners are taken as an example to illustrate the proposed method.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
• /
• pp.233-240
• /
• 2000

Nuclear power plant structures may be exposed to aggressive environmental effects than may cause their strength and stiffness to decrease over their service lives, Although the physics of these damage mechanisms are reasonably well understood and quantitative evaluation of their effects on time-dependent structural behavior is possible in some instances such evaluations are generally very difficult and remain novel. The assessment of existing RC containment in nuclear power plants for continued service must provide quantitative evidence that they are able to withstand future extreme loads during a service period with an acceptable level of reliability. Rational methodologies to perform the reliability assessment can be developed from mechanistic models of structural deterioration using time-dependent structural reliability analysis to take earthquake loading uncertainties into account. The final goal of this study is to develop the reliability analysis of RC containment structures. The cause of the degrading is first clarified and the reliability assessment has been conducted. By introducing stochastic analysis based on random vibration theory the reliability analysis which can determine the failure probabilities has been established.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
• /
• pp.229-232
• /
• 1999

Nuclear power plant structures may be exposed to aggressive environmental effects that may cause their damage mechanisms are reasonably well understood and quantitative evaluation of their effects on time-dependent structural behavior is possible in some instances, such evaluations are generally very difficult and remain novel. The assessment of existing steel containment in nuclear power plants for continued service must provide quantitative evidence that they are able to withstand future extreme loads during a service period with an acceptable level of reliability. Rational methodologies to perform the reliability assessment can be developed from mechanistic models of structural deterioration, using time-dependent structural reliability analysis to take loading and strength uncertainties into account. The final goal of this study is to develop the analysis method for the analysis for the reliability of containment structures. The cause and mechanism of corrosion is first clarified and the reliability assessment method has been established. By introducing the equivalent normal distribution, the procedure of reliability analysis which can determine the failure probabilities has been established.