Earticle

The tube structure is one of the most efficient lateral resisting structural system. But as a result of the flexural and shear flexibilities of the frame members, the behavior of the tube structure is complicated by the shear lag phenomenon which has the effects of increasing the axial stress in the corner columns, decreasing those in the inner columns and reducing the lateral stiffness of the structure. The outrigger system is a solution to decreasing the shear lag phenomenon and displacement. The purpose of this study is to evaluate the seismic performance of tube structure system with outrigger tube structure. This study adopts response spectrum analysis and pushover analysis. To analyze the effect between outrigger tube structure and soil types, this study performed capacity spectrum method(CSM) under the seismic load. A intersection point of capacity curve and demand curve is performance point. In this paper, after searching for performance point according to return period, performance level is evaluated.

In performance-based seismic design, it is clear that the evaluation of the nonlinear response is required. One of the most accurate earthquake analysis method for the performance evaluation of structure is nonlinear response history analysis, but it is time-consuming and necessitate more efforts. Approximate methods are presented for estimating the capacity of structures while subjecting earthquake ground motions. This is made possible by exploiting the connection between the nonlinear static response of structure and the dynamic response of SDF system whose backbone matches the structure’s pushover curve. The nonlinear direct spectrum method(NDSM) and the uncoupled modal response history analysis(UMRHA) are proposed and studied to evaluate nonlinear response of structures, without iterative computations, given by the structural linear vibration period and yield strength from the pushover analysis. In this study, it is to compare the practicality and the reliability of approximate nonlinear methods with respect to mixed building structures and various earthquakes.

In these days, many of high-rise residential buildings are constructing with flat plate slab structure system. These buildings tend to adopt a 'building frame system' and 'dual system' as primary seismic resisting structural system. But, there exist several ambiguities and difficulties in designing theses systems in practical. So, 'KBC2005 & commentary(0306.6.1)' published in 2006 November refer that if the moment frame of 'The dual system(R=5.5)' cannot resist the above 25% of seismic load, it will transfer 'The building frame system' in the form "Immediate moment frame(R=5)"and the shear wall does not have the necessity which will resist completely the seismic load. By appling 'KBC2005 & commentary', flat plate slab structure system are designed according to the method , such as "Deformation Compatibility" and "immediate moment frame(R=5)". The objective of this study was to compare with stress behavior and effectiveness according to two design-method of seismic load resisting system in flat plate slab.

The research verified the validity of interpretation by comparing and analyzing existing experimental values using a grudge element interpretation program. Various interpretation models have been proposed by introducing a reinforcing method for shearing flexural of strengthened reinforced concrete beam with a composite panel as an additional variable. Lastly ductility and beam capacity were examined and compared with an interpretation model at varying levels of reinforcement, reinforcement method, load-displacement relationship and crevice phase

The objective of this investigation is to study the elasto-plastic behavior of hybrid beams using precast ductile fiber reinforced cementitious composites(DFRCCs) from-work and normal concrete subjected to vertical load. The hybrid beam, which DFRCCs is filled with concrete, expected to raises durability of concrete. For comparison, DFRCCs beams using PolyVinyl Alcohol fibers and Polypropylene fibers, and general reinforced concrete beam are tested. The length of specimens is 1920mm, the section is 170x270(mm), the thickness of the DFRCCs form is 35mm, the main bar is D13, the tie bar is D6. The research results clearly showed that the proposed hybrid beam showed stable hysterisis behaviors than general concrete beam.

Collected & analyzed the results of the domestic experiments and examined the application to ACI Code, Euro code, JBDPA Code, so that complete the formular of column's shear strength which is suited to domestic state. For that purpose, the result of estimation classified by the formula of shear strength, the strength of concrete, ho/D ratio, as a whole the formular of JBDPA Code & Euro code is close to domestic state. So when we compute the shear strength of the column, we can apply the formular of Japanese standard of earthquake-proof, but in the case of the ratio of shear span is under 1, it is safer that use the amende and suggested strength formular from JBDPA Code.

This paper is an experimental study on the structural behavior of reinforced concrete beam when in using various of CFRP and the ductility of beams using various type of CFRP, It is complete and bends conduct, the stiffener against reinforcement beam it puts the place objective which a reinforcement effect in reinforcement quantity of RC beam examines closely a ductility conduct test, examines closely.

In this study, experimental research was carried out to evaluate and improve earthquake-resistant performance of the reinforced concrete beam-column joints using high ductile fiber composites mortar and advanced reinforcing detailing. Three reinforced concrete beam-column joints were constructed and tested to evaluate the effect of test variables, such as the high ductile fiber composites mortar and advanced reinforcing detailing under load reversals. Test results show that specimen(BCJIP, BCJP) designed by the improvement of earthquake-resistant performance and ductility were attained more load-carrying capacity and stable hysteretic behavior.

Recently the construction of high-rise reinforced concrete building is progressively increased as the social demands. It is significantly important factors such as economy, the safety of structure, and the flexibility of internal space. Therefore new structural system is also required to be attained the reduction of story height, the flexibility and efficient use of space. The most suitable structural system is with the economy and flexibility, flat plate slab system in high-rise reinforced concrete building. In this research, it was focused in the improvement of seismic performance in the flat plate system using high ductile fiber reinforced mortar. It was evaluated the seismic performance in the critical region of slab-column connection. The flat plate system, designed by the high performance and safety, was developed as a new technique in the application of high-rise R/C building.

The present study emphasizes the development of nonlinear model of shear behaviour of HPFRCC panel to apply in seismic retrofit of reinforced concrete buildings. To model the shear behaviour of HPFRCC panels, the original Modified Compression Field Theory (MCFT) for conventional reinforced concrete panels has been newly revised for reinforced HPFRCC panels. The proposed shear model of HPFRCC panel has been applied in the prediction of seismic retrofitted reinforced concrete buildings with infilled HPFRCC panels.

Current design practice of electric transmission tower is based on allowable stress design. But, it is difficult to find the reason for collapse of the transmission tower by the above design approach since the collapse occurred by secondary large deformations based on material and geometrical nonlinear behavior. The influence factor for the nonlinear behavior is mainly residual stress, initial imperfection and end restraints on members. In past study, necessity of the nonlinear analysis is examined through the comparison between elastic analysis and inelastic analysis. In this study, to reduce the complexity caused by the nonlinear analysis, a new analytical method (equivalent nonlinear analysis technic) is proposed. To confirm the reliability of the proposed, the computed ultimate load of transmission tower using the method was compared with that of the nonlinear finite method. Also, electric transmission tower experienced actual collapse in the past was analyzed by the proposed method and the cause of collapse was examined. Finally, the result of this study will be utilized in order to apply LRFD design approach to electric transmission tower design specification.

SC(steel plate-concrete) structure is recently used in nuclear power structure because of its efficiency of construction. In this study, an analytical study to investigate the behavior and strength in wall-slab connection of SC structure was carried out. Finite element analysis was performed and the result of the analysis was well matched with the experimental result. By varing the thickness of shear plate and friction coefficients and distance of applied load from the wall, the influence of the parameters on the joint strength and failure modes were examined. Finally. It was confirmed that the joint strength formula proposed in previous research gives conservative results.

Behavior and strength of rib stiffened SC wall-slab connection was investigated. Six prototype specimens of wall-slab connections were fabricated and tested. Structural safety of the specimens was confirmed through the monotonic loading test. Based on the experimental observations, strength formula of the joint was proposed. To enhance the reliability of the proposed strength formula, analytical verification was performed through inelastic finite element analysis. Effect of parameters, such as, load point, friction coefficient, on the joint strength was examined. Finally, it was confirmed that the proposed formula gives conservative value in most cases.

In order to recycled wast concrete which is occurred from demolition of the old building, it is effective that the recycled aggregate used as structural concrete aggregate. For used recycled aggregate with structural concrete, the structural capacity must be confirmed. This Study investigated bond capacity which follows in difference of absorption of the aggregate between rebar and concrete Test results show that there are not a difference of bond strength and slip behavior according to absorption ratio of natural and recycled coarse aggregate.

Although the research of high strength materials is in process briskly in the inside and outside of the country, in south korea, the research of high strength materials is insufficiency. Generally shear resistance of RC beam is influenced dominantly by amount of shear-reinforcing bars(p w ) and yied strength(f wy). Therefore, I come to the conclusion that if use shear reinforced bar with shear reinforced bar, it leads to decrease of the quantity of shear reinforced bar and effects on the security of shear-restraint force of member. This study experimented with not only the mixture of high strength-reinforced bar and U-shaped reinforcement normal strength -reinforced bar devises efficient improvement, but also it incites improvement of bond capacity and carries out an experimental study for improvement of member resisting force, finally it evaluates bond capacity quantitatively on the lines of main reinforcement the restraint method.

In this paper, the structural capacity of building with damaged joint was evaluated through a nonlinear analysis process. For this, 5, 10 and 15 story buildings are designed according to the current design code and the joint of building is modeled to have the reduced stiffness or strength. And then a nonlinear static analysis using DRAIN-2DX program is performed. Analysis result showed that decrease of base shear closely depended on the strength loss in joint and independed on the stiffness loss. However, the yield drift increased when the stiffness increased.

The purpose of this study is to investigate experimentally the ductile behavior of R/C shearwall with different details of transverse reinforcement in boundary element under cyclic load. Based on the test result, it was shown that the difference of transverse reinforcement in boundary element didn't impact greatly on the initial strength. However, the specimen with spiral type reinforcement showed higher strength and more flexible behavior than that with traditional hoop.

The general structural behavior of shearwall is affected by both axial compression and bending moment. The objective of this paper is to study nonlinear behavior characteristic of RC-Shear wall through nonlinear analysis process. Sectional analysis is performed using X-TRACT program. Main variables in the analysis are concrete compressive strength, confinement type, vertical reinforcement ratio, lateral confinement ratio in boundary column and vertical reinforcement ratio in wall. From the analysis, it was found that the stiffness variation was not high even compressive strength of concrete increased. However ultimate strength was improved. The flexural strength increased when spiral type reinforcing is applied in boundary column.

Three reinforced concrete beam using high ductile fiber-reinforced mortar composites were constructed and tested under monotonic loading. Experimental programs were carried out to evaluate and improve the repair performance of such test specimens, such as the failure mode, the maximum strength, and crack control. All the specimens were modeled in one-third scale size. Test result shows that specimens(BSHT2 1.5, BSHT2 3.0) designed by the improving of repair performance using the high ductile fiber composite mortar were attained significantly cracking control due to the fiber bridging and increased the load carrying capacity by 10% in comparison with the standard specimen(BSS).

This paper presents a methodology for modelling the masonry stone pagoda structures using 3D scanning date. Stone pagoda structure can not be correctly studied by conventional methods of structural mechanics like the ones that are used to analyse today's structures. To solve these problems, this study presents the discrete element method. Masonry structures should be treated as discontinuum structure with mechanical behavior which is different from continuum structure. 3DEC program that is used by this study is a three-dimensional numerical program based on the discrete element method for discontinuum modeling. Therefore, through the investigation of masonry stone pagoda in Gameunsa Temple Site, we present structural modelling and analysis method of masonry stone pagoda through 3D scanning date and the 3DEC program to represent the behavior.

This paper is concerned with the damage of road sign by strong wind. The need of a study on wind load of the road sign has been recognized for many years. The wind tunnel tests have been conducted on five types road sign model of wind force and moment coefficient in turbulent boundary layer flows. The effects of wind force are examined with three different road sign plate sizes and two different structure of road signs. Actual wind load can be different from the accounting regulation. Therefore, we compare experiment data with standard data. We find many similarities between experiment data and regulation data. And its results are presented in this paper.