Recently, prefabricated bridge is studied actively to reduce the term of works. However, most of the research is limited to the primary structures like piers, girders and decks, etc, not to facilities like bridge rails or curbs. In this study, curb model and settling method for steel bridge rails suitable for prefabricated bridges were proposed along with verifying structural performance according to highway bridge standard specifications.
This study mainly focuses on presenting a rational procedure of assessing target reliability level of nuclear containment. The target reliability level can be obtained by considering LCC(Life Cycle Cost) of damage and operation. The LCC evaluation results in the different environmental situations. It is verified that this deviation of LCC can be adjusted by selecting the proper initial target reliability. In addition, slight increase of initial target reliability for the nuclear containment aiming a longer service life, therefore, the total expected loss during the extended service years can be maintained in the same level as the total loss expected in the 20-year service life for the existing containment structures.
A wide range of sensors are used to figure out structure behaviors such as strain gauge, vibrating wire sensor, and etc. For stress sensor, it is exact but can only measure relative changed values. For displacement sensor, it is also exact but hard to figure out 3D displacement. Motion capture system can solve these problems so widely used in various fields.
This paper is aimed to define accuracy for motion capture system through the capturing a stopped passive marker. From this findings, possibility to apply to structural health monitoring especially in building structure was verified.
This paper presents a subspace system identification algorithm for time-invariant structural system. System matrices are estimated from input-output data. The main computational tools are the LQ and the singular value decomposition in subspace system identification. The accuracy and stability of estimated system matrices are influenced by the parameters of Hankel matrix. For stable SI, the optimal parameters of Hankel matrix are determined by considering the computational cost and the accuracy of system matrix.
The purpose of this study is to present the damage detection method on shear building structures by wavelet transformation. The damage location index using 1st mode shape is observed theoretically to find out damage location. The damage detection method is applied to numerical analysis model such as MATLAB for the verification. The shacking table test on 3 story shear building is performed for the examination of the damage detection method. Wavelet transformation and directly fast fourier transformation are performed for the data, and damage index is compared. Finally the applicability of the wavelet transformation for damage detection is examined.
Since the loads acting on a buildings cannot be precisely expected or measured, rational evaluation on structural health is in difficulties. From this reason, a numerical approach for evaluation process is presented for the displacement evaluation of continuous beams in this study. A modified curve fitting in which boundary conditions are considered and its application to continuous beam with 2 span are dealt with.
This paper analyzed the CO2 emission of existing buildings on the operation phase in the declined residential area of Jeonju old town. The average CO2 emission to square meter of residential buildings in jeonju was calculated.
This paper presents a mathematical model on the longitudinal mid-span extension of the Tamar Bridge, UK by using 6 months data of temperatures and an extension starting from July 2010. Linear models of temperature input-extension output were identified for all the combinations of input temperatures. The model using two temperatures, one temperature on the top of the mid-span section and the other on the bottom, was found to be the best with the fitness value 95.9% while single-temperature input models had maximum fitness 80%. This observation might be explained by the temperature gradient at the section: in the existence of the temperature gradient, two temperatures in the section may represent the temperature distribution of the section well while a single temperature can't. A further study needs to be carried out to verify it by a thermal simulation on a Finite Element model of the bridge.
This Study is described safe and efficient Damage Estimation for underwater structures with equipment(3-D scan sonar). Which is conducted inspection in compliance to actual domestic situation and take a dive investigation of actual underwater dam facility directly.
In this study, principal check points in design of the damper were able to examine through the process of comparison between theoretical prediction and experimental verification for performance of high-damped rubber damper based on compressive deformation energy absorption.
For maintenance of existing bridges, it is very important to identify the current state of bridge. In order to evaluate load rating of a bridge, real behavior characteristics of bridge obtained by analyzing the measured data and static/dynamic responses calculated through numerical analysis are needed. However, evaluating current state and/or load rating of bridge is not easy, because there are many difficulties in measuring bridge behaviors and making accurate FE model. The Korea Expressway Corporation has developed the ‘Smart Load Rating Method’ for bridge which is able to evaluate the current state of bridge with dynamic properties and has been applying in Highway bridges. In this study, we have successfully fulfilled analyzing dynamic properties and evaluating the state of an old steel gerber bridge in Texas USA by using the Smart Load Rating method
Recently, durability of concrete structure is getting more attentions in advanced countries. It is important to evaluate the durability qualitatively since it is the case that design strength does not correspond to durability. Therefore, there has been an attempt to evaluate the quality of concrete structures in European and Japan. The target of this project is to establish an inspection method and a verification system of concrete quality based on the knowledge accumulated in the previous researches.
The purpose of this study is to present the damage detection method on shear building structures by mode shape. The damage location index using 1st mode shape is observed theoretically to find out damage location. The damage detection method is applied to numerical analysis model such as MATLAB and MIDAS GENw for the verification. Finally the shacking table test on 3 story shear building is performed for the examination of the damage detection method.
The key findings of the paper are as follows: Numerical parameters study of the interface-element was carried out, the friction angle depends on rockfill zone material and normal and shear stiffness coefficient of the two materials (concrete and rockfill), the average values were found to be the most appropriate.
In this research an experimental study was carried out to decrease the damage caused by the collision of bridges as earthquake load was added. For the experiment, we designed a model of successive bridge composed of a reinforced concrete bridge top and I section steel. As for damper, we ourselves designed and produced a MR damper of 30 KN. The result proved that the MR damper of our own design was effective to prevent the successive bridge model from colliding.
Recently, infrared thermography that analyzes a blistering zone from surface temperature is widely used in stone cultural heritages. This study focused on quick detection and quantitative modeling of blistering zones. Blistering modeling for the stone cultural heritages should be carried out as following orders; aquisition of thermography image, establishment of critical temperature, monochromatic processing, extraction of vector line, mapping of blistering zone, and calculation of deterioration rate. The deterioration rate of blistering zones of Cheomseongdae observatory and Sungnyemun stone block foundation using the infrared thermography were 1.5% and 6.6%, respectively.
This paper presents a study of system identification on the tilt response of the L-type retaining wall located at Tanhyun 11th ACE Apartment, Ilsan in order to understand mechanism how the structure behaves in operational conditions and to provide a reference tilt values for assessing structural abnormality. The retaining wall was extraordinarily tall (14m) in urban area so the long-term monitoring system had been installed with 3 tilts-meters and 9 temperature sensors operational from Oct 2004 upto Nov 2007. By using 5-months continuous data in which all the 12 channels were up and running, the state-space equation (SSE) model has been identified by finding the best fitness model among all possible 511 combinations of input temperatures out of the 9 temperatures. The SSE model achieved the validation fitness of 90% which was quite accurate considering various unexpected noises often found in field measurements.
To contribute to efficient and safe inspection and maintenance of underwater facilities by identifying the damage status of underwater parts through collecting and analyzing local and overseas data. The carrying out actual underwater surveys to perform characteristics analysis and evaluation on the underwater facilities and present a Application Method of 3-D side scan sonar for Assessment of Underwater Structures.
This study presents bond performance of insulated concrete sandwich panel systems considering different type of insulation through two-way acting insulated concret sandwich panel mock-up test under wind pressure.
In this study, we conducted Life-Cycle Reliability Analysis Classified by Structure Movements in Removal PSC Beam Bridge. in short, we secured experimental values of bridge design factor and perform a detailed behavior analysis of structure system. finally, we could accomplish an Life-Cycle Reliability Analysis with considering of an environmental factor and variability of loading.
We defined limit state function by statistical method (Response Surface Method, RSM) and calculated confidence indicator and Probability of Failure using reliability interpretation technique(FORM). eventually, we could compute Performance Profile and compare deterioration form according to time history by structure movements.