This paper proposes substructuring method using experimental model of only upper MDOF structure and verifies its applicability to shaking table test. The structure considered in the test is a five-stoty shear type building model which is divided into two parts, of which one is lower three floors for a numerical substructure and the other is upper two floors for a experinlental substructure. The experimental substructure is excited by the shaking table and the acceleration data for the input of shaking table is obtained numerically from lower numerical part. For implementation of the proposed substructuring method, a controller of the shaking table is designed reflecting experimental model. In comparison with acceleration responses, which are measured from experinlental part of 3rd, 4th, and 5th floor and are numerically calculated from the original five-stoty structure, it is observed that the experimental results match well with the numerical results in both time and frequency domain.
In this study, the wind response characteristics of a transmission tower are investigated through stochastic analysis considering the dynamics of a transmission line, The assemblage of the transmission line and insulator are modeled as a double pendulum system connected to the SDOF model of the tower. It is observed that the background component of the overturing moment induced by the wind response of the transmission line has considerable portion in the total overtuming moment. Based on this observation, a rotational viscoelastic damper is proposed for the suppression of the transmission line response to reduce wind load on the transmission tower. To verify the effectiveness of the proposed damper, time history analysis is conducted for various wind velocities. From the result of the analysis, the proposed damper is proved to be effective in the reduction of the background component rather than the resonance component of the support reaction of the transmission line.
In this study, a seismic design methodology for a friction damper based on the story shear force of an elastic building structure is proposed. First, using two normalization methods for the slip-load of a friction damper, numerical analyses of various single-degree-of-freedom systems are performed. From those analyses, the effect of the slip-load and brace stiffness was investigated and the optimal stiffness ratio of the brace versus original structure was found. Second, from the numerical analysis for five multi-story building structures with different natural frequency and the number of story, reasonable decision method for the total number of installation floor, location of installation and distribution of slip-loads are drawn. In addition, an empirical equation on the optimal number of installation floor is proposed. Finally, the superiority of the proposed method compared to the existing design method is verified from the numerical analysis.
Since the beginning of our military history, we are continuously interested in supplying apartment for military officers. So we possessed 72,361 households and used in 2002. however, 18% of those are over 20years and need to be remodeled. Department of Military has taken this fact seriously to solve the problems, they built more new buildings, rent public buildings and remodeled the old one. But, The procedure of present military apartment remodeling has many problems at the stage of evaluating the priorities in various remodeling projects which have been caused from lots of corps. I’ve reviewed the study of military apartment business and applied the AHP(Analytic Hierarchy Process) method which is effective to evaluate the priorities in various groups’ decision.
To solve existing old building was reconstruction whose regulation has been stronger than before. On the other side, Remodeling project become active. In spite of Remodeling project activation policy of a government, relaxation of some regulation and Remodeling technology development, etc, but Domestic Remodeling market place did nor yet vitalize. This is application of existing resources on condition which has working place, restriction of method and unreliable existing building’s career management, so difficulty of getting information has many risk factors. The more serious problem is lack of understanding about Remodeling, limit of communication and lack of systematic process about complexity of project, etc. of Remodeling project operator and each participant, happening construction term delay, waste of budget, a fall of quality. This study suggests each process work scope of project execution and various kinds analysis tools for decision making for efficient management and building of project system and builds project execution process system. identification.
Recent building structures are superior in its ability but they are light and flexible, and so have problems of habitability induced by building vibration. In general, the problem of vertical vibration is not considered in structural design. However, in terms of serviceability for inhabitants in buildings, the estimation of vertical vibration in design stage is important. Characteristics of vertical vibration is changed by modeling method of beam-column joint. To check the characteristics of vertical vibration, many tests and analyses were conducted on constructing building in Seoul. Results of tests and analyses were compared using transfer function. As a results, to check the vertical vibration characteristics, the cramp ratio of beam-column joint must be considered and reduced to 50% ~ 60% in structural design.
Earthquake resistance design has been developed many countries like Japan, USA, Mexico, New Zealand etc., which countries have experienced many earthquakes. Nowadays, earthquake resistance design has come into worldwide use. In Korea, the seismic design regulations have been established since 1988 in order to minimize the economic losses. Recently performance based design method has been adopted as a new Earthquake resistance design method. These regulations, however, are targeted for newly constructed buildings, In Korea, there are no regulations for existing buildings that built before 1988. So, we need to prepare the regulations that evaluate the seismic performance, furthermore proper retrofitting design guideline needs to be proposed when remodeling old buildings. This study was performed that many existing apartments is being a Remodeling object when considering the present condition of existing apartment and the problerns of cost and environment in the future plan. When Remodeling construction is reviewed by former the Seismic Performance Evaluation Method, generating problems is evaluation by using Push-over. According to this, it provides the appropriate method of calculating the Seismic Performance Index.
Recently, earthquakes occur over 30 times a year in Korea. In addition, earthquakes originating from the neighborhood countries were sensed in Korea and caused serious human casualties and economic loss. In Japan, U.S.A., New Zealand and etc., forces seismic design of building structures to prevent seismic damage. In Korea, seismic design has been applied to building structures with a scale larger than defined in the building code since 1988. However, serious seismic damages are expected for wall-type apartment buildings, which were designed before 1988 without application of seismic design. Therefore, appropriate seismic retrofitting methods that are economical and easy to construct are required for such buildings. In this study, seismic retrofitting methods using steel plates or sections are developed for the wall-type apartment buildings. Proposed retrofitting methods improve lateral stiffness of the wall-slab system without excessive increment of loads on base structure. The effect of retrofitting using plates, T-sections and H-sections was examined experimentally for wall-slap system test models. In the experiment, the performance of the joint and slab of the test models was improved and the retrofitting effect was proved to be excellent.
The mechanical behavior of concrete-filled glass fiber reinforced polymer columns is affected by various factors including concrete strength, stiffness of tube, end confinement effect, and slenderness ratio of members. In this research the behavior of slender columns was examined both experimentally and analytically. Experimental works include 1) compression test with 30cm long glass fiber composite columns under different end confinement conditions, 2) uni-axial compression test for 7 slender columns, which have various slenderness ratios.Short-length stocky columns gave high strength and ductility revealing high confinement action of FRP tubes.The strength increment and strain change were examined under different end confinement conditions.With slender columns, failure strengths, confinement effects, and stress-strains relations were examined.Through analytical work, effective length was computed and it was compared with the amount of reduction in column strength, which is required to predict design strength with slender specimens.This study shows the feasibility of slender concrete-filled glass fiber reinforced polymer composite columns.
In this paper, fly ash was investigated as a basic Si-Al ingredient of geopolymer. Based on compressive and flexural strength, the replacement percentage of fly ash and 3 types of curing regimes were studied to obtain the optimum synthesis condition. The results showed that geopolymer containing 30% fly ash that was prepared at 80˚C for 8 hours, exhibited high mechanical strength. The compressive and flexural strength of the fly ash based geopolymer were 32.2 and 7.15MPa, respectively. In order to investigate the durability behavior of fly ash based geopolymer concrete, CI permeability, freeze-thaw tests were also carried out. The measured results indicated that fly ash based gopolymer concrete had 2.63 times lower coefficient of chloride-ion diffusion and could withdraw 2.2 times more freeze-thaw cycles as compared to Portland concrete with the same compressive strength.