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In predicting the track-ground vibrations induced by moving trains, it is generally assumed that the irregularities of two rails of a track are identical and fully correlated. This assumption leads to identical contact forces at the contact point of wheels and rails. In the present paper, the uncorrelated profile of the two rails is considered to investigate their influence on the train-track-ground vibrations. For this purpose, a three-dimensional (3D) finite element model capable of simulating interactions between a 3D train and track by using a nonlinear Hertz contact method is developed. Nonlinear Hertz contact is represented by the tensionless stiffness between the wheels and rails. The rails are modeled as 3D Euler–Bernoulli beam elements. Solid brick elements represent the model components, such as the track (other than rail) and ground. A detailed description of an iterative numerical algorithm is presented to establish the integrations of the train and track system. This iterative numerical algorithm can calculate the responses and forces at the interaction point between each wheel and rail to incorporate the uncorrelated profile of two rails, instead of only considering the interaction at the centroid of the wheelset axle and the center of the track. A comparative study is conducted by considering various train speeds and three different track cases. The results show that an increase in train speed causes an increase in ground vibration in the case of uncorrelated profiles of two rails of a track. Moreover, the effects of correlated and uncorrelated profiles of two rails of a track are investigated in terms of the train-track-ground responses.

Background: The aim of this pilot study was to assess the safety and dosing of scolopendrid pharmacopuncture (SPP).Methods: A total of 40 healthy Sprague-Dawley rats (males and 20 females 20) were selected following a 7-day inspection and acclimation period. SPP was administered via intramuscular injection, over a 2-week period using 3 doses including a high-dose [0.84 mg of scolopendrid per kg of body weight (BW)], a meddose (0.42 mg/kg BW), and a low-dose (0.21 mg/kg BW). The control group was injected with sterile water into the muscles. Unusual changes caused by administration of the test substance were observed. Weight, feed intake, organ weight, and hematological examinations were compared among the groups. Using the SPSS statistical program, Levene’s test was performed to evaluate the homogeneity of variances, and a one-way ANOVA test was subsequently performed to assess the significance between each test group.Results: During the experiment no animals died. Weight change, food consumption, organ weight, hematological test, and blood biochemical tests showed no significant differences in the treatment groups compared to controls.Conclusion: No toxicological changes related to the administration of test substances were observed. Therefore, the LD50 (lethal-dose that kills 50%) of scolopendrid pharmacoupuncture in rats was greater than 0.84 mg/kg.

As the performance of photoanodes for solar water splitting steadily improves, the extension of the absorption wavelength in the photoanodes is highly necessary to substantially improve the water splitting. We use a luminescent back reflector (LBR) capable of photon upconversion (UC) to improve the light harvesting capabilities of Mo:BiVO4 photoelectrodes. The LBR is prepared by dispersing the organic dye pair meso-tetraphenyltetrabenzoporphine palladium and perylene capable of triplet-triplet annhilation-based UC in a polymer film. The LBR converts the wavelengths of 600-650 nm corresponding to the sub-band gap of Mo:BiVO4 and the wavelengths of 350-450 nm that are not sufficiently absorbed in Mo:BiVO4 to a wavelength that can be absorbed by a Mo:BiVO4 photoelectrode. The LBR improves the water splitting reaction of Mo:BiVO4 photoelectrodes by 17 %, and consequently, the Mo:BiVO4 /LBR exhibits a photocurrent density of 5.25 mA cm-2 at 1.23 V versus the reversible hydrogen electrode. The Mo:BiVO4 /LBR exhibits hydrogen/oxygen evolution corresponding to the increased photocurrent density and long-term operational stability for the water splitting reaction.

Perovskite solar cells (PSCs) are currently exhibiting reproducible high efficiency; the manufacturing of low cost, scalable electron transport layers (ETLs) is becoming increasingly important. However, this remains a challenge for electron transport layers that exhibit excellent optical/electrical properties while being a thin film of simple morphology. Here we demonstrate the PSC of a 2D photonic crystal nanodisk (ND) array ETL that is compact, but greatly enhances light harvesting. The ND array is fabricated by nanosphere lithography using a monolayer of self-assembled polymer spheres as a physical mask. We fabricate ND arrays of various lattice constants simply by controlling the size of the polymer spheres. Optimal ND arrays exhibit strong forward scattering and optical confinement effects, greatly improving light harvesting in the perovskite layer. We also observe that the ND array improves charge transport by reducing contact resistance with the perovskite layer. ND array ETL PSCs reach 19% maximum power conversion efficiency, with low photocurrent-voltage hysteresis and stable photocurrent output.

A luminescent solar concentrator (LSC)-based photovoltaic (PV) system, consisting of an LSC panel that harvests light and an edge-mounted solar cell that produces electricity using the photoluminescent light, is promising for semitransparent building-integrated photovoltaics (BIPVs). Here, we demonstrate a highly efficient and highly semitransparent LSC-PVs capable of harvesting dual wavelength bands. We used a triplet–triplet annihilation-based photon upconversion (UC) LSC that luminesce high energy green light by absorbing low energy red light, as well as downshift LSC that luminesce green light by absorbing ultraviolet light. The luminescent light concentrated from the two LSCs is absorbed by a dye-sensitized solar cell (DSSC) having a high extinction coefficient at this wavelength. Our optimized dual band LSC-PV exhibited 27% higher power conversion efficiency than the LSC-PV that absorb a single wavelength band. With respect to practical applications, the dual band LSC-DSSCs were fabricated in the fo...

In this paper, a continuum model is proposed for static and dynamic analyses of a three-span suspension bridge with three-dimensionally curved main cables. To obtain equations of motion for this model, coupled differential equations are derived for vertical displacements of a main cable and a girder as well as lateral displacements of a main cable subjected to external loads. A compatibility equation of a three-dimensionally curved cable is also derived. Utilizing the Galerkin method, the equations of motion are obtained in matrix form. A case study bridge is used to verify the continuum model against a finite element model. Verification results show that, for distributed static loads on the girder and temperature changes in the main cable and the hangers and for dynamic moving loads on the girder, the continuum model can accurately determine static and dynamic responses, namely displacements, velocities, accelerations, bending moments, and shear forces of the girder and additional horizontal forces in the main cable.

This paper presents analytical solutions for bending, buckling and free vibration analyses of isotropic plates on elastic foundations using a simplified first-order shear deformation theory. Unlike the conventional first-order shear deformation theory, the present theory contains only two variables and has many similarities to the classical plate theory. For the elastic foundations, the Pasternak model which has two parameters is used. Equations of motion are derived from Hamilton’s principle. Analytical solutions of deflections, moments, shear forces, buckling loads and natural frequencies are obtained for rectangular plates with various boundary conditions. Numerical examples for various aspect ratios, side-to-thickness ratios and foundation parameters are presented to verify the validity of the present theory. Comparative study shows that the present theory is accurate and efficient in predicting bending, buckling and free vibration responses of isotropic plates on elastic foundations. Parametric study shows the effect of the elastic foundations on the behavior of the plates.

An effective numerical method is proposed for the three-dimensional nonlinear analysis of mooring cables using catenary theory. In this method, the mooring line is divided into finite number of catenary elements. In addition to self-weight, each catenary element is subjected to drag force due to steady ocean currents. The proposed procedure is validated by comparing the results with those of the shooting optimization and the finite element methods. Finally, a parametric study is conducted to study the effect of extensibility on the static response of mooring cables. The effects of fluid drag forces and cable extensibility on mooring cable tension, equilibrium configurations, and stressed lengths are illustrated for two- and three-dimensional mooring cable problems. From the numerical results, the method is found to be numerically stable, and it provides a more rational static response for mooring cables.

Needs for I/O bandwidth have rapidly increased with the explosive growth of internet traffic and data technologies. To accommodate the required high bandwidth, a DSP-based PAM-4 transceiver became the most robust solution with increased usage of channel capacity [1]–[4]. However, to be integrated with many transceivers in a chip, low-power designs are becoming critical factors for DSP-based transceivers. This paper presents an MM-CDR-based ADC timing skew control, which greatly reduces ADC complexity and power, and a low-power DSP using an approximate multiplier. Besides this, $\mathrm{g}_{\mathrm{m}}$ boosting of the TX driver and low-power TX DAC help reduce total power consumption.

Offshore floating wind turbines are widely recognized as promising renewable energy devices capable of harnessing wind energy in deep water. In addition to mooring lines, hydrostatic stiffness of the floating platform plays a key role in the stability of the offshore floating wind turbine. Apart from the geometry of platform, hydrostatic stiffness depends on its degrees of freedom. Therefore, it changes with motions of floating wind turbine and should be computed instantaneously. However, it is common practice to neglect the platform degrees of freedom and use linear hydrostatic stiffness in floating wind turbines analysis. Linear hydrostatic stiffness neglects the platform's motion and is computed at its undisplaced position. These shortcomings of linear hydrostatic stiffness can significantly influence the dynamic response of floating wind turbine. In the current study, a nonlinear hydrostatic stiffness with the purpose of its use in the analysis of offshore floating wind turbines is presented. The presented nonlinear hydrostatic stiffness uses the instantaneous position of floating platform and takes into account platform degrees of freedom. The effect of nonlinear hydrostatic stiffness is demonstrated through analysis of three leading types of floating wind turbines. The results show influence of hydrostatic nonlinearity on dynamic responses of floating wind turbines.

The dynamic analysis of train-bridge systems has been a popular research topic for a long time; however, studies on cable-stayed bridges subject to train and seismic loads remain limited. Cable-stayed bridges can experience large vibrations under external periodical loads due to the high flexibility caused by their long decks and cables. Previous approaches to modeling the cables have limitations in accuracy, principle, or calculation efficiency, making them unsuitable for dynamic analysis with numerous time steps for long-span bridges with many cables. Furthermore, track irregularities and earthquakes bring additional excitations to the train-bridge system and threaten its structural and running safety. Thus, an accurate and fast approach to modeling and analyzing cable-stayed bridges under train loads and other excitations is needed. In this study, an improved parabolic cable element is included for dynamic analysis. This cable element facilitates a faster calculation while maintaining an accuracy similar to that of a catenary cable element. The coupled equation-of-motion of the train and cable-stayed bridge system is derived and solved via the time integration method. The effects of railway track quality and seismic load are investigated through the dynamic responses of train-bridge systems by considering various classes of tracks and levels of seismic intensities, respectively. The impact factors of the vertical displacement of the deck and the tensions in cables are used to represent the behaviors of the bridge, while the maximum accelerations of vehicle bodies are used to represent the behaviors of the train. Track irregularities and seismic load significantly increase the responses of the bridge and train. With increased train speed, the negative effects of poor quality track on the responses of the train-bridge system increased; however, with increased seismic loads the effects were found to decrease.

The widely use of bridge structures in modern high-speed railway makes the possibility that a train face to an earthquake when it’s running on a bridge increased. The running safety of the train requires more research attention to be paid. This study investigated the effect of bridge properties on the running safety of a high- speed train under earthquakes using a fast calculation approach. The train-track-bridge (TTB) system is simplified as a three-dimensional model for the dynamic analysis. The rigid contact between rails and wheels is considered, while the direct coupling iteration approach is adopted to solve the dynamic responses of the TTB system. The track irregularities, wheel hunting motion, and multi-support earthquake, which considers the time lag between the seismic waves at different supports, are considered as the excitations to the TTB system. The randomness of the excitations is considered by the pseudo-excitation method (PEM) and the statistical results of the TTB system random responses are obtained. The derailment factor and the off-load factor are used to evaluate the running safety of the train. In the case study, the damping ratio, pier height, and track eccentricity are considered as the various parameters of the bridge properties. Through the PEM analysis, the mean value and standard deviation of the running safety factors were obtained used to evaluate the running safety of the train under an earthquake condition. The evaluation approach for the running safety used in this study can help the engineers to simply check the designs of the railway bridges without performing large time cost calculation work.

The evaluation of the effective length factor (K-factor) of columns based on the system buckling approach is a convenient tool in the stability design of multi-story frames. This method is superior to other analytical approaches, such as isolated subassembly and story-based approaches, in that inter-column and inter-story interactions are inherently taken into account. In this study, in order to investigate the effect of nonconservative forces on buckling loads and K-factors for the single- and multistory framed structures, the system buckling approach is presented. For this purpose, the finite element model, based on the Hamilton’s principle, is formulated for the stability analysis of framed structures subjected to nonconservative forces. In numerical examples, buckling loads and K-factors for single- and multi-story frames subjected to conservative or nonconservative forces are evaluated and compared with those obtained by other researchers. Especially the effect of the stiffness ratio of girder to column on K-factors is investigated for nonconservative systems.

Submerged floating tunnels (SFTs) are innovative structural solutions to waterway crossings, such as sea-straits, fjords and lakes. As the width and depth of straits increase, the conventional structures such as cable-supported bridges, underground tunnels or immersed tunnels become uneconomical alternatives. For the realization of SFT, the structural response under extreme environmental conditions needs to be evaluated properly. This study evaluates the displacements and internal forces of SFT under hydrodynamic and three-dimensional seismic excitations to check the global performance of an SFT in order to conclude on the optimum design. The formulations incorporate modeling of ocean waves, currents and mooring cables. The SFT responses were evaluated using three different mooring cable arrangements to determine the stability of the mooring configuration, and the most promising configuration was then used for further investigations. A comparison of static, hydrodynamic and seismic response envelope curves of the SFT is provided to determine the dominant structural response. The study produces useful conclusions regarding the structural behavior of the SFT using a three-dimensional numerical model.

An improved continuum model of three-span suspension bridges has been developed to study the effects of hanger extensibility on free vertical vibrations. This model can be applied to both h...

This paper addresses the dynamic response of a continuous beam bridge with different levels of track irregularities under a single, moving high-speed train. The train is modeled as one-foot sprung masses. The bridge is described as an Euler-Bernoulli beam supported by several hinged supports. Rayleigh damping coefficients of the bridge are calculated by using the modal damping ratio. Random track irregularities are generated by power spectrum density functions. The interaction equation of motion is derived and then solved by using the Newmark-beta method combined with the Newton-Raphson method. The dynamic impact factors of a single-span simply supported bridge and a five-span continuous beam bridge under the same train are calculated and compared for verification. Additionally, a three-span continuous beam bridge with various damping ratios and track irregularities under a Korea Train Express (KTX) train is used as an example to investigate the dynamic impact factors at the midpoints of different bridge spans in both downward and upward directions, the deck rotations at the bridge supports, and the average maximum acceleration of the train bodies under different conditions.

The purpose of this study is to understand daily variation of short-wave radiation trends according to the state of surface and observation of atmosphere conditions in downtown and suburban observation area. The followings are main results from this study. 1) We found out daily air temperature variation of downtown is less than that of suburban area because of bigger heat capacity of artificial elements such as massive buildings and pavements. 2) It is more effective to estimate of air condition by water vapor pressure than relative humidity in the atmosphere. 3) The difference of solar radiation ratio between downtown and suburban area is dependant on different atmosphere conditions at two observation stations.

The buildings constructed with steel structure is coated with certified Sprayed Fire Resistive Material(SFRM) to resist from fire. All the building materials lose their initial performances as time passes, so they need durability. In a previous Paper(Journal of The Korean Society of Hazard Mitigation in April 2014 to be posted) covered standardization of the methods for assessing the durability of SFRM. In Korea, more than 90 percent of SFRM are used indoors. So their fire performance were tested under indoor conditions before and after accelerate wet/dry cycling and temperature cycling to standardize the methods for assessing their durability. This paper is a follow-up study of the previous paper, that will be suggested the final draft based on validation tests and review the details for creating the Korea Industrial Standard.

최근 국내에서는 건축물에서 공간의 미관이나 활용성 때문에 유리창 및 유리벽체의 사용에 대한 관심이 높아지고 있다. 하지만, 건축물의 내부공간은 화재시 연소확대 및 인명피해를 막기 위해 건축법에 따라 내화구조로 방화구획을 하여야 한다. 이러한 방화구획벽에 비차열 유리를 사용할 경우, 화재시 인접 거실로 복사열에 의한 화재의 확대, 인명 피해가 일어날 수 있다. 본 연구에서는 비차열 유리창에 대한 복사열의 위험성을 평가하기 위하여 내화실험을 실시하여 실험체 이면에서의 온도와 열류량을 측정하여 그 결과를 분석하였다.ABSTRACTRecently in Korea, the interest for using window and window-wall in building picks up due to the beauty and utiliza-tion of space. But, interior space of the buildings shall be compartmentalized by fire resistance structures in accordancewith the Korean building codes to prevent the spread of flame and damage of human life in fire. In case of installing non-insulated glazed window in compartment wall, the flame spread to adjacent space and the damage of human life by radi-ant heat can occur in fire. On this study, to confirm the risk of radiant heat for non-insulated glazed window in fire, thefire resistance tests were conducted. The temperature rise and heat flux on unexposed space was measured and analyzed.Keywords : Non-insulated glazed window, Fire risk, Fire test, Radiant heat, Temperature rise

The shear deformable thin-walled composite beams with closed cross-sections have been developed for coupled flexural, torsional, and buckling analyses. A theoretical model applicable to the thin-walled laminated composite box beams is presented by taking into account all the structural couplings coming from the material anisotropy and the shear deformation effects. The current composite beam includes the transverse shear and the restrained warping induced shear deformation by using the first-order shear deformation beam theory. Seven governing equations are derived for the coupled axial-flexural-torsional-shearing buckling based on the principle of minimum total potential energy. Based on the present analytical model, three different types of finite composite beam elements, namely, linear, quadratic and cubic elements are developed to analyze the flexural, torsional, and buckling problems. In order to demonstrate the accuracy and superiority of the beam theory and the finite beam elements developed by this study, numerical solutions are presented and compared with the results obtained by other researchers and the detailed three-dimensional analysis results using the shell elements of ABAQUS. Especially, the influences of the modulus ratio and the simplified assumptions in stress-strain relations on the deflection, twisting angle, and critical buckling loads of composite box beams are investigated.

In this paper, the refined pate theory is improved to account for the effect of thickness stretching in functionally graded plates. The refined plate theory has fewer number of unknowns and equations of motion than the first-order shear deformation theory, but accounts for the transverse shear deformation effects without requiring shear correction factors. The displacement field of the refined plate theory is modified by assuming a parabolic variation of the transverse displacement through the thickness, and consequently, the thickness stretching effect is taken into consideration. Closed-form solutions of simply supported rectangular plates are presented, and the obtained results are compared with 3D solutions and those predicted by higher-order shear deformation theories. Verification studies show that the proposed theory is not only more accurate than the refined plate theory, but also comparable with the higher-order shear deformation theories which contain more number of unknowns.

(Received November 4, 2013 / Revised December 18, 2013 / Accepted December 18, 2013)In order for efficient recycling and eco-friendly treatment of construction waste, there is a need to apply a building separati on and dismantling technique early on in the stage of waste generation. This study was conducted to analyze the relevant domestic circumstances and propose the applicable range of buildings in order to introduce a building separation and dismantling system to Korea. For this purpose, related policies and systems implemented overseas and the current situation of buildings were examined , and the workability of separation and dismantling of buildings according to their uses was compared. Also, the economic impact of t he separation and dismantling system was examined and a survey was conducted, seeking the opinions of the relevant companies regarding the need for the system and the selection criteria for eligible buildings. Based on the results, it was determined th at it wouldbe impossible to apply the separation and dismantling system to all buildings in Korea, considering the current technical power and economic situation, and that the system should be introduced in phases, according to the building classification determined bas ed onfloor area and use, as the cost may vary depending on a number of variables including the level of difficulty and field conditi ons. 키워드 : 분별해체, 재활용, 해체공사Keywords : Dismantlement, Recycling, Deconstruction* Corresponding author E-mail: batsun@kict.re.kr

In this paper, a simple first-order shear deformation theory is presented for laminated composite plates. Unlike the existing first-order shear deformation theory, the present one contains only four unknowns and has strong similarities with the classical plate theory in many aspects such as equations of motion, boundary conditions, and stress resultant expressions. Equations of motion and boundary conditions are derived from Hamilton’s principle. Analytical solutions of simply supported antisymmetric cross-ply and angle-ply laminates are obtained and the results are compared with the exact three-dimensional (3D) solutions and those predicted by existing theories. Comparison studies show that this new first-order shear deformation theory can achieve the same accuracy of the existing first-order shear deformation theory which has more number of unknowns.

In this paper, an efficient analysis method considering both geometric and material nonlinearities is proposed for predicting the ultimate strength and behavior of multi-span suspension bridges. The geometric nonlinearities of the cable members due to sag effects are captured using the catenary element, while the geometric nonlinearities of the beam-column members due to second-order effects are captured using the stability functions. The material nonlinearities of the cable and beam-column members are considered using elastic–plastic hinge and refined plastic hinge models, respectively. A simple initial shape analysis method is presented to determine the deformed shape and initial cable tension of the bridge under dead loads. Numerical examples are presented to verify the accuracy and efficiency of the proposed method. In addition, a case study on a four-span suspension bridge is carried out to show the capability of the proposed method in estimating the strength and behavior of very large scale structures.

Fire doors are installed on the openings in buildings to protect fire spreading in the event of fire. In foreign countries, fire doors whose fire resistance performance is from 20 minutes to 180 minutes are installed depending on required fire resistance performance of where fire doors are installed. But, in Korea, it is difficult to protect fire spreading in the event of fire because fire doors only having integrity of 1 hour are installed regardless of the position of fire doors. Therefore, it is needed to improve the system related to fire doors by strengthening the required fire resistance performance depending on where fire doors are installed and introducing insulation performance. To do so, the performance verification of the existing fire doors must be done first. In this study, fire resistance performance of the steel fire doors which are used widely depending on core material was evaluated. As a result, most specimens had the integrity performance and secured insulation performance of around 10 minutes depending on core material.

A 6-Gb/s differential voltage mode driver is presented whose output impedance and pre-emphasis level can be controlled independently. The voltage mode driver consists of five binary-weighted slices each of which has four sub-drivers. The output impedance is controlled by the number of enabled slices while the pre-emphasis level is determined by how many sub-drivers in the enabled slices are driven by post-cursor input. A prototype transmitter with a voltage-mode driver implemented in a 65-nm CMOS logic process consumes 34.8-mW from a 1.2-V power supply and its pre-emphasized output signal shows 165-mVpp,diff and 0.56-UI eye opening at the end of a cable with 10-dB loss at 3-GHz.

Analytical solutions for bending, buckling, and vibration analyses of thick rectangular plates with various boundary conditions are presented using two variable refined plate theory. The theory accounts for parabolic variation of transverse shear stress through the thickness of the plate without using shear correction factor. In addition, it contains only two unknowns and has strong similarities with the classical plate theory in many aspects such as equations of motion, boundary conditions, and stress resultant expressions. Equations of motion are derived from Hamilton’s principle. Closed-form solutions of deflection, buckling load, and natural frequency are obtained for rectangular plates with two opposite edges simply supported and the other two edges having arbitrary boundary conditions. Comparison studies are presented to verify the validity of present solutions. It is found that the deflection, stress, buckling load, and natural frequency obtained by the present theory match well with those obtained by the first-order and third-order shear deformation theories.

OBJECTIVE We aimed to investigate the associations of post-stroke emotional incontinence (PSEI) with various psychiatric symptoms and quality of life independent of potential covariates in survivors of acute stroke. METHODS A total of 423 stroke patients were assessed within 2 weeks of the index event. Psychiatric symptoms were assessed by the Symptom Checklist-90-Revised (SCL-90-R), which has nine domains comprising Somatization, Obsessive-Compulsive, Interpersonal Sensitivity, Depression, Anxiety, Hostility, Phobic Anxiety, Paranoid Ideation, and Psychoticism. Quality of life was measured using the World Health Organization Quality of Life abbreviated form (WHOQOL-BREF), which has four domains related to physical factors, psychological factors, social relationships, and environmental context. Associations of PSEI with scores on the SCL-90-R and WHOQOL-BREF were investigated using pairwise logistic regression model adjustment for potential sociodemographic and clinical covariates. RESULTS PSEI was present in 51 (12.1%) patients. PSEI was associated with the Obsessive-Compulsive, Interpersonal Sensitivity, and Hostility symptom dimensions of the SCL-90-R and with the psychological factors and social relationships domains of the WHOQOL-BREF independent of important covariates including previous stroke, stroke severity, and physical disability. CONCLUSION PSEI causes some aspects of psychiatric distress and negatively affects psychological and interpersonal quality of life. For patients with PSEI, special attention to psychiatric comorbidity and quality of life is needed, even in the acute stage of stroke.

The super convergent laminated composite beam element is newly derived for the lateral stability analysis. For this, a theoretical model of the laminated composite beams is developed based on the first-order shear deformation beam theory. The present laminated beam takes into account the transverse shear and the restrained warping induced shear deformation. The second-order coupling torque resulting from the geometric nonlinearity is rigorously derived. From the principle of minimum total potential energy, the stability equations and force-displacement relationships are derived and the explicit expressions for the displacement parameters are presented by applying the power series expansions of displacement components to simultaneous ordinary differential equations. Finally, the member stiffness matrix is determined using the force-displacement relationships. In order to show accuracy and superiority of the beam element developed by this study, the critical lateral buckling moments for bisymmetric and monosymmetric I-beams are presented and compared with other results available in the literature, the isoparametric beam elements, and shell elements from ABAQUS.

A simple refined shear deformation theory is proposed for bending, buckling, and vibration of thick plates resting on elastic foundation. The theory accounts for parabolic distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. The number of unknowns of present theory is two as against three in the case of other shear deformation theories. The elastic foundation is modeled as two-parameter Pasternak foundation. Equations of motion are derived from Hamilton's principle. Analytical solutions are obtained for rectangular plates with two opposite edges simply supported and the other two edges having arbitrary boundary conditions. Comparison studies are presented to verify the validity of present solutions. It can be concluded that the proposed theory is accurate and efficient in predicting the bending, buckling, and vibration responses of thick plates resting on elastic foundation.

This paper proposes a theoretical solution of elastic critical buckling load of infinitely long pipelines with non-uniform thickness under external pressure. The non-uniform cross section of pipelines can be considered as corroded or stiffened pipelines so that this paper can be a fundamental research of pipelines that are essential technology for offshore industries. The theoretical solution of pipelines with non-uniform thickness is derived with an assumption that a cylindrical shell under external pressure can be considered as a simple ring. The eigenfunctions are derived to obtain the critical buckling load. The reduced thickness and the reduced range are considered as variables in parametric analysis. The finite element analysis is performed to verify the theoretical solutions and the results of the analytic method and the finite element method are in good agreement.

A continuum model for a three-span suspension bridge with a floating girder is presented to investigate its dynamic behavior under moving loads and vertical support motions. This model can consider hangers’ extensibility. Coupled differential equations for the vertical displacements of a main cable and a girder subjected to external loads are presented. Equations of motion in matrix form are obtained by introducing the Galerkin method with shape functions for the main cable and the floating girder. A numerical example is used to verify the continuum model against a finite element model.

Submerged floating tunnel (SFT) is a new solution for the transportation infrastructure through sea straits, fjords, and inland waters and can be a good alternative to long span suspension bridges and immersed tunnels. The mooring cables/anchors are main structural components to provide restoring capacity to the SFT. The time domain dynamic problem of SFT moored by vertical and inclined mooring cables/anchors is formulated. The dynamic analysis of SFT subjected to hydrodynamic and seismic excitations is performed. As the cable stiffness determines the deformation ability of SFT, therefore it becomes crucial to evaluate the effect of mooring cable stiffness on the response of SFT. The displacements and internal forces of SFT clearly specify that the vertical/tension leg mooring cables provide very small stiffness as compared to inclined mooring cables. In order to keep the SFT displacements within an acceptable limit, the effect of cable stiffness should be properly evaluated for practical design of SFT.

The k-factor method has been widely used in design of steel-concrete composite bridges to determine indeterminate stresses. The accuracy of k-factor method is examined by a comparative analysis with the equivalent load method in a continuous 2-span composite bridge. To improve the accuracy, the direction of creep stress has to be modified and the variety of section must be considered. This paper suggests j-factor method which can improve the accuracy of k-factor method with simple modification.

For large size digital television, an intra-panel interface scheme with clock-embedded differential signalling is developed which connects a timing controller and column data driver at 2.0 Gbps. A two-wire differential data channel has tri-level and clock information is embedded in it. Embedded clocking eliminates the skew between data channel and clock, which makes the clock-data recovery very simple. A prototype chip has been implemented in a standard 45-nm CMOS technology.

This paper performs the static analysis of multi-span suspension bridges using the deflection theory. Applying the deflection theory conventionally used in three-span suspension bridges to multi-span suspension bridges, the horizontal forces of the main cables due to live loads are obtained by converting the suspension system to the equivalent beam system and using the compatibility equation of cables for four spans. Iterative computations are used due to nonlinearity of the differential equations. The results, such as deflections and moments of girders and horizontal forces of the main cable, are compared with the finite element analysis for verification. The resultant values from two methods are almost the same. Finally, using the linearized deflection theory, parametric studies are performed by influence line analyses for parameters such as the side-to-center span ratio, the tower stiffness ratio and the sag to span ratio. From the parametric studies, alternatives to reduce displacements of girders in the center span and girder moments of all spans are investigated.

The openings for fire doors and fire shutters are installed on fire compartment to stem fire spreading and evacuation passage in building. Fire spreading tend to grow through these openings, so it is important to organize the standard related to opening protectives. In case of the fire door in Korea, its criteria is only integrity 1 hour regardless of fire resistance of a building member, therefore it is difficult to protect the fire spreading effectively. In this study, foreign performance criterion of the fire door were reviewed and the base data for improving way about the fire door performance criteria were suggested.

The openings for fire doors and elevator doors are installed on fire compartment to stem fire spreading, evacuation passage and elevator hoistway in building. Fire spreading tend to grow through these openings, so it is important to organize the standard related to opening protectives. Unlike in the past, due to being tall and large, the elevator for evacuation is being more important. For this reason, it is required for elevator door to be safe in fire and it is necessary for the glazing installed on fire doors to be reviewed with respect to fire spreading. In this study, foreign performance criterion of the fire elevator door and the fire-protection-rated glazing were reviewed and the base data for improving way about the fire performance criteria were suggested.