When fresh concrete is exposed to extremely low temperature, the free water in the concrete transforms into ice, which causes decrease in compressive strength of concrete. For estimating the frost damage of the conrete structure, we use ultrasonic velocity method and estimate the compressive strength.

In this study, repair and reinforcement priority determining method for each component of existing dams is suggested. Condition assessment results from in-depth inspection followed by “specific guide for in-depth inspection on dams” are used. Condition assessment is subdivided into several steps and evaluation indices are determined by considering weights such as influence coefficients and adjustment factors for each component through all of the steps. These weights are counted backward to determine the priority for each component and facility. An algorithm is designed to analyze this procedure and 4 target dams are adopted to verify the method. This method can be used for establishing an efficient maintenance strategy related to the repair and reinforcement priority determination.

A new research project entitled 「Development of Evaluation and Analysis Technologies for Road Sink」 was initiated last year under the sponsorship of Korea Agency for Infrastructure Technology Advancement and Ministry of Land, Infrastructure and Transport. In this article, outlines of this project is briefly introduced including research goal, scope, current major activities, etc.

The purpose of this study is to evaluate propriety of impact factor in railway design code about truss bridge with dynamic loading test. This study also analyzes and compares impact factor and railway design code. A impact factor of all members of the truss is lowered by revising railway design code in 2013. The result of this study indicates that a reasonable standard for impact factor is required, because current impact factor which is specified in railway design code could not properly reflect dynamic response of specific type and member.

This study proposes a measurement method using angular sensors to measure deformation and displacement of bridges. The proposed measurement method consists of gyroscope sensors and data processor to transform angular to vertical displacement. This study contains experimental evaluation to verify the applicability of the proposed method. 4-points bending tests were conducted on a small-sized girder specimen. The displacements were measured with both conventional LVDT and gyroscope sensor to compare the accuracy of the proposed method. It is estimated that the method using gyroscope shows some noise in data, but the method using gyroscope has advantages to measure the vertical displacement. Therefore if the sampling rate and synchronizing problems can be approved, it can be a good alternative measuring method for the deformation of the bridges.

The crack propagation on lining is compared for 10 years with previous length of crack in PISD(Precise Inspection for Safety and Diagnosis) depending on the width from 0.2mm to 1mm. Analyzed crack on horseshoe single tunnel is increasing in proportion to square time and linear increment. In this proposal, the extent of crack propagation can be estimated during the elapsed time. The tendency of crack can also be used in evaluating the life cycle of tunnel.

From the past, space structure have been widely used as sports arenas, religious facilities. And the demand and research for retractable structure is increasing recently. Therefore, we classify the retractable mechanism which is divided according to the retractable method of structures and survey the present condition of retractable structures built around the world.

An experiment was conducted to recycle sulfur which is industrial by-product, by producing concrete mix materials. production of specimens were implemented on the replacement of modified sulfur emulsion with cement. this paper presents data on the experimental results of strength test of the each specimens.

Acceleration measurement is widely employed, because acceleration sensors generally have low noise and cost effective. To determine cable tension, FFT analysis of measured acceleration data is widely used. This study proposes a stay cable measurement system using acceleration data to determine the cable tension and vibration amplitude. A small light-weight wireless sensor is also proposed to increase the applicability.

This study proposes a measurement method using angular sensors to measure deformation and displacement of bridges. The proposed measurement method consists of gyroscope sensors and data processor to transform angular to vertical displacement. This study contains experimental evaluation to verify the applicability of the proposed method. 3-points bending tests were conducted on a small-sized girder specimen. The displacements were measured with both conventional LVDT and gyroscope sensor to compare the accuracy of the proposed method. It is estimated that the method using gyroscope shows some noise in data, but the method using gyroscope has advantages to measure the vertical displacement. Therefore if the sampling rate and synchronizing problems can be approved, it can be a good alternative measuring method for the deformation of the bridges.

The purpose of this study was to evaluate the sulfate attack of ternary blended concrete based on low-heat cement for reducing the heat of hydration. The main parameters were water-to-binder ratio and curing temperature on the matching mixtures. Test results revealed that compressive strength ratio at each age was superior to the developed mixtures than control mixtures. Whereas, the mass change ratio was superior to the control mixture at all ages.

Based on the fabrication experiences of modulization in the global country, tolerance guide of SC module was issued in the their Design Code. In case of KEPIC Code 2015, we have the same level of tolerance guide with other countries. But we need more specific technology and accuracy control system.

SUPER concrete poontoon is developed to overcome shortcomings about corrosion problem of steel poontoon and the insufficient freeboard line of concrete poontoon. The top slab resists for truck load or sidewalk live load. And the soffit slab and outer wall resist for horizontal and lift components of wave pressure. The optimum characteristic compressive strength of SUPER concrete poontoon is analyzed 100Mpa. SUPER concrete poontoon have advantageous durability compared with the steel or general strength material in a lot of Chloride Exposure at offshoer, These are checked by Fick's diffusion curve and depth of neutralization. Finally, SUPER concrete is alternative material for steel and concrete poontoon.

Selection of a typical four companies products of domestic structural one-component sealant, high temperature, low temperature, room temperature to set up the environment for each of 80, -20, 20 ℃ and the left and right displacement of the test piece 30, 15, 0% of the maximum compression / expansion It was carried out by the repeated fatigue.

Recently, the concern on the deterioration of concrete pavement due to de-icing salts and its counter measurements has been increased. Especially, a scaling phenomenon of concrete is defined as a general loss of surface mortar or mortar surrounding the coarse aggregate particles on a concrete surface. This problem is typically caused by the expansion of water due to freezing and thawing cycles and the use of de-icing chemicals. This paper discusses the testing conditions of freezing-thawing and scaling resistance.

This study is to find compatibility materials of industrial by-product and ocher mixed plants mats at different formulation. We compare Four formulation. Experiment are permeability, water content, cohesion of mat. Resultingly, Ocher formulation have effectively strong cohesion of met.

This study investigates the effect of elevated temperatures on the pore structure of cement paste which, in turn, can provides information to evaluate the damage level of concrete structures due to fire. Mercury intrusion porosimetry (MIP) test was conducted for this investigation. Test results showed that the higher the temperature, the higher is the pore volume of cement paste and the wider is the pore distribution.

The purpose of this study is to compare and analyze the flexural behavior characteristics of the RC(Reinforced Concrete) beam and the SIFCON(Slurry Infiltrated Concrete) beam. Three-point loading test was progressed about a RC beam and SIFCON beams of 6 according to various heights and with or without tensile reinforcement. As a result, producing structure using SIFCON can reduce weight and the use of steel reinforcement because SR300 shows higher maximum load than Control specimen.

We studied design and structural analysis of jack-up barge footing system that can be safely and quickly installed offshore support structure. In this paper, we checked the buckling strength for a structural member in spudcan based on DNV-RP-C201

In this research, we carried out design and analysis with joint of concrete supporting structure for offshore wind energy. We developed load transfer mechanism about applied load induced from steel tower to concrete foundation. Also, a commercially available finite element program, ABAQUS 6.10, is used to analyze behavior of structure.