In this paper, an experimental research was carried out to compare the capability to control a MR-damper attached structure, which turned out to differ according to its vibration control direction whether vertical or horizontal. The target structure for the experimental test was a real size asymmetrical cable-stayed bridge. The MR-damper for vibration control was designed 30KN to fit into the target bridge. For the performance experiment of the MR-damper, the el-centro earthquake wave using three shaking table was inflicted on the model bridge structure, once horizontally and then vertically. Finally, each control capability, different according to its direction, was compared and evaluated. The experiment proved that the MR-damper was able to damp in a different way according to its control direction(horizontal or vertical) and also to work effectively damping the acceleration responses of the structure.
Damage evaluation of railway bridge is presented. Changes of dynamic properties between damaged case and repaired case using free vibration responses are evaluated. Power Spectrum and Cross Power Spectrum of Fourier Transform for vibration responses are used to evaluate the dynamic properties of the bridge to check out the difference before and after the reinforcement.
It has been changed from conservative method that require partial destruction of concrete structure to new method that is nondestructive method or require just tissue of concrete structure for the stability evalution of concrete structures. The estimation technique that is the purpose of this project are very forehanded at the time of state-of-the-art equipments that give diagnosis work efficiency and accuracy is presented in this study. This study included that the discovering a equipment for collection of concrete powder, the suggestion of thermal analysis at the estimation of neutralization of concrete, the estimation technique for suggestion of appropriate repair time, the estimation methods that are to presume carbonation processing amount and to assume damage degree caused by freezing and thawing action.
It was evaluated penetration depth and spalling resist thickness by compressive strength. As a result, it was found that the more compressive strength is increased, the penetration depth is suppressed. And the result of this study are similar to modified NDRC formula and US ACE formula.
An optimum cross section of a precast modular bridge was drew by using the combinational optimization method. The constraints for the optimization procedure including the width and the thickness of the bottom flange, and the maximum area of the cross section, etc. were considered, and weight of the girder was minimized to draw an optimum cross section. Furthermore, the segmentation of the girder in its longitudinal direction was studied for satisfying the requirement of traffic law about overloading.
This paper experimentally evaluates effects of fiber ratio of the seismic performance of infill walls. Variable of study was a concrete and fiber ratio (PVA1.3+PE0.2 and PVA0.75+PE0.75). The experimental investigation consisted of cyclic loading tests on 1/3-scale models of infill walls. The experimental results show that SHCC specimens was more ductile behavior.
Various type of composite beams have been developed to utilize advantages of reinforced concrete and steel structural system with making up for their weaknesses. In this study, prestressed composite beams with discontinuous corrugated webs are presented, in which discontinuous web plates improve the introduction efficiency of prestress by accordion effect and enhance composite action between steel beam and concrete compared to typical plane webs. Two prestressed composite beam with discontinuous corrugated webs, four prestressed composite beam with trapezoidal corrugated webs, and one corrugated webbed composite beam without prestress were fabricated and tested to evaluate their serviceability, ductility and flexural strength.
To clarify the load-carrying behavior of RC beams caused by the rebar fracture and the expansive crack along the longitudinal reinforcement due to aggregate expansion simulating ASR, experimental study was carried out. From the test result, all specimens caused by the rebar fracture failed in shear tension. Moreover, cracking behavior and crack propagation highly influenced by the range of expansive crack.
The objective of this study is to investigate the seismic performance of hybrid coupled shear wall connection with new toughness material, pseudo strain hardening cementitious composites (PSH2C). Test variable of this study is the embedment length of steel coupling in connection region. The results showed that Specimen PSH2C-ST with longer embedment length of steel coupling beam exhibits good seismic performance than Specimen PSH2C-STE.
The shell of form-finding is most important in design procedure of the cooling tower, because the shape of the shell determines the sensitivity of dynamic behavior of the whole tower against wind excitation. The purpose of the study is the investigation of the influences of the geometric parameters of the cooling tower shell on the structural behavior. As a result, a hyperbolic rotational shell with the small radius overall will yield the shell geometry with a higher first natural frequency and thus a wind-insensitive structure. Linearly and nonlinearly numerical analysis are demonstrated influence of the shell-geometric parameters on structural behaviours. The results of this study may be informative for the form-finding of the cooling tower shell.
This study is that larger scale and longer span of construction in concrete structures urge increasing use of mass concrete, high-flowing concrete among them is more widely used for improvement of quality and concrete constructability, but it may cause occurrence of cracks due to autogeneous shrinkage as well as heat of hydration. In this regard, the present study provides comparative analysis on temperature characteristics subject to varied locations through experiments adopting a PSC girder in which high-flowing concrete is used; moreover, it analyzes heat of hydration through the FEM to perform the crack analysis of the PSC girder in such a way that the result thereof is compared with that of the experiment.
The main factor which makes RC structures weakening is corrosion of reinforced-bar that inserted in elements of the structure, and there are many researches that trying to figure out how to prevent degradation of strength of the re-bar. Because of that various factors effect on the deterioration of RC structures complexly, this paper suggest the indicator which can assess the failure probability of the structures.
The objective of this study is to investigate the failure modes of steel coupling beam-wall connection. Test variable of this study is types of material used, concrete and with pseudo strain hardening cementitious composites (PSH2C). The results showed that Specimen PSH2C-SB with longer embedment length of steel coupling beam exhibits good seismic performance than Specimen HCWS-SB.
Mostly, solar panel support structure has been constructed as flat-type structure. But, it is not harmonized with the existing buildings. Therefore, this study presents the curved support structures and performs the structural analysis for the selection of member size. Also, the structural safety is evaluated through joint experiments and finite element analysis.
In this study, experimental research was carried out to improve the structural performance of reinforced concrete beam-column joint using high performance FRP materials in existing reinforced concrete building.
Test result shows that retrofitting specimen(LBCJ-CRU, CRS, CRUS) designed by the improvement of seismic performance of reinforced concrete beam-column joints load-carrying capacities were increased 1.30~1.54 times in comparison with the standard specimen.
This experimental study evaluates of seismic performance on strain-hardening cement-based composite (SHCC). The objective of this study is to evaluate of seismic capacity reduction factor on two sides confined SHCC infill walls. The experimental results as cseismic capacity reduction factor are not significantly different.
This study is performed to analytic evaluate of two side constrained precast infill wall with SHCC. As a result, SHCC-E specimen shows more ductile behavior than SHCC-V specimen. Analytical results are compared with experimental results.
This paper is to evaluate experimentally the long-term behavior of concrete beam with FRP Bars. All beams reinforced with steel, GFRP, AFRP and CFRP were under sustained loading for approximately 300 days. As the results of test, it found that calculated results obtained from ACI 440.1R-06 were overestimated comparing to test results, and it exhibits the variability of the long-term deflection factor along the types of FRP bar
The existing Full-staging method(FSM) has problems of economic efficiency and clearhead decline due to short applicable span length. This study proposes the thermal prestressing method (TPSM) with eccentric bracket in FSM. The study contains an analysis of TPSM as well as static loading analysis for the proposed method. It was verified that sectional stiffness of applied H beam girder is increased and ultimate strength is improved as well.
Corrosion of the steel reinforcement in a cold and saline environment leads to the overall deterioration of reinforced concrete structures. To avoid such deterioration, Glass Fiber Reinforcement Polymer(GFRP) rebars are used in place of steel reinforcement. In the present paper, in order to examine the effect of reinforcement ratio of concrete beam reinforced with lap-spliced GFRP bar, nonlinear finite element analyses are performed.