• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.635-638
• /
• 2007

In this paper, we described the fundamental concepts of proposed structural health monitoring system for Uldolmok Tidal Current Power Plant focusing on the use of smart sensors including fiber bragg grating sensors and macro fiber composite sensors. The structural health monitoring system can play an important role to maintain the structural safety for offshore structures like as bridges and high-rise buildings. In the case of tidal current power plant, the monitoring system is much more important since the structures are usually constructed at the site with severer environmental loadings such as high current speed.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.414-417
• /
• 2006

In order to evaluate the shear strength of stud connectors in composite bridges using lightweight concrete decks, static push-out tests were performed. Sixteen push-out specimens were tested during this investigation. The test program consisted of two groups according to deck type, one is cast-in-place(CIP) concrete deck, the other is precast concrete deck. The experimental parameters were concrete compressive strength and bedding layer thickness. Based on the experimental results, the ultimate shear strength and the stiffness of shear connectors in lightweight concrete decks are assessed.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.451-452
• /
• 2010

Prestressed concrete I girder bridge has been one of the most widely used bridges in the world because of its excellent construction feasibility, economic efficiency, serviceability, and safety. But in Korea, the PSC bridge has not been utilized for long span because of high girder height in its standard design. Thus, the results confirm that it is possible to applicate the continuous PSC girder with end cross beam anchorage system using multi-stage prestressing technique.

• Steel and Composite Structures
• /
• v.22 no.5
• /
• pp.1141-1162
• /
• 2016

Concrete-filled double skin steel tube (CFDST) beam-columns are widely used in industrial plants, subways, high-rise buildings and arch bridges. The CFDST columns have the same advantages as traditional CFT members. Moreover, they have lighter weight, higher bending stiffness, better cyclic performance, and have higher fire resistance capacities than their CFT counterparts. The scope of this study is to develop finite element models that can predict accepted capacities of double skin concrete-filled tube columns under the combined effect of axial and bending actions. The analysis results were studied to determine the distribution of stresses among the different components and the effect of the concrete core on the outer and inner steel tube. The developed models are first verified against the available experimental data. Accordingly, an extensive parametric study was performed considering different key factors including load eccentricity, slenderness ratio, concrete compressive strength, and steel tube yield strength. The results of the performed parametric study are intended to supplement the experimental research and examine the accuracy of the available design formulas.

• Steel and Composite Structures
• /
• v.2 no.6
• /
• pp.475-488
• /
• 2002

In steel bridges fatigue cracks are sometimes repaired by placing drilled holes at the crack tips. From the meaning that the drilled holes stop the propagation of cracks, they are called stop-holes. Since stop-holes are regarded as an emergency measure to delay crack propagation, usually some substantial repair follows. However, if the stress at the stop-holes is below their fatigue limit, fatigue cracks would not be expected to occur. The purpose of this study is to present the conditions under which stop-holes prevent the reinitiation of fatigue cracks. The fatigue limit of stop-holes and the equations necessary to estimate the maximum stress on the circumference of the stop-holes are provided.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2001.04a
• /
• pp.223-232
• /
• 2001

This paper describes Genetic Algorithm-Based Relay Search Method, RS-GA, which is developed in this study to search the multiple design variables in the design space. The RS-GA based on Simple-GA consists of some functions to search many variables from some wide variable space. It repeats a Simple-GA, that is the convergence process of the Simple-GA, which makes many time reiteration itself. From the results of the numerical studies, it was actually found that RS-GA can search all peak-variable from the 2D functions including 5 peaks. Finally, RS-GA applied for design-strengthening problems in composite plate girder bridges using the external prestressing technique is also verified.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1999.10a
• /
• pp.27-34
• /
• 1999

This study presents the concept and the effects of the lifting two supports method that makes get economical design sections and efficient stress condition. The analysis of relation between critical sections and ratios Is done. Also, connection between critical sections and design variable is analyzed. In order to resolve the effects of the lifting two supports method, sections which was designed with the existing method, lifting support method, are used. Finally, it is proved that the new method is more efficient than the existing methods in economy and structure.

• Steel and Composite Structures
• /
• v.3 no.1
• /
• pp.13-32
• /
• 2003

In this paper design and fabrication information system for steel bridge construction is studied and proposed according to the progress of Construction CALS/EC in the construction industry in Japan. The data exchange in this system bases on the text file as well as CAD data with simplified drawings. The concept of this system is discussed following the analysis on the issues of the conventional system. The application of the product model is also discussed including effects and issues on the inspection system. This paper is based on the study carried out by Special Committee on Construction CALS of JASBC to which author belong.

• Structural Engineering and Mechanics
• /
• v.86 no.3
• /
• pp.325-336
• /
• 2023

A significant component of many civil constructions such as buildings, reservoirs, bridges, and sports halls, concrete has become increasingly popular due to its versatile properties. Concrete's internal characteristics change due to the use of different types of fibers, including changes in its microstructure, volume, and hole dimensions. Additionally, the type, dimensions, and distribution of fibers in concrete can affect the results of flexural strength tests by affecting its compressive and tensile strength. Due to a lack of information, fiber concrete is a new composite material in the production industry that requires laboratory studies to determine its behavior. This study investigated the bending behavior of multilayer slabs made of concrete reinforced by polyamide-propylene fibers against impact in weight lifting exercises. Results showed that adding fibers to concrete slab samples improved the mechanical properties while replacing them hurt the mechanical properties and failure of polymer fiber-reinforced concrete. On the other hand, adding and replacing fibers increases durability and has a positive effect.

• Steel and Composite Structures
• /
• v.45 no.2
• /
• pp.263-279
• /
• 2022

With the span and arch rib size of concrete-filled steel tube (CFST) arch bridges increase, the hydration heat of pumped mass concrete inside large-size steel tube causes a significant temperature variation, leading to a risk of thermal stress-induced cracking during construction. In order to tackle this phenomenon, a hydration heat conduction model based on hydration degree was established through a nonlinear temperature analysis incorporating an exothermic hydration process to obtain the temperature field of large-size CFST. Subsequently, based on the evolution of elastic modulus based on hydration degree and early-age creep rectification, the finite element model (FEM) model and analytical study were respectively adopted to investigate the variation of the thermal stress of CFST during hydration heat release, and reasonable agreement between the results of two methods is found. Finally, a comparative study of the thermal stress with and without considering early-age creep was conducted.