The artificial neural network (ANN) based damage detection method is prposed for the steel moment frames with beam-hinge collapse mechanism. The natural frequencies, modeshapes, flexural moment of columns are employed as the values for the input layer while the raios of rotational stiffness of connections before and after damage are employed as the values for the output layer. The 5-story steel moment frame with beam-hinge collapse mechanism is used as the example structure.

We know that the failure of high performance concrete pavement occurs in the aspects of its structure, environment, material, and construction. We have been able to identify the reason why no construction should be permitted when average daily temperature is below 4 degree celsius. We must pay careful attention to the curing management and comply with the standards of concrete production and construction.

This paper aims to evaluate the safety of the cable supported bridges under the occurrence of damages on cable system. There are more than 50 cable supported bridges currently built in the Korean peninsula and efficient and systematic maintenance and management are in great demand. However, safety of the bridges cannot be under estimated and should be properly evaluated. In this paper, two bridges (one cable-stayed bridge and one suspension bridge) in South Korea were investigated their safety based on the damage scenario of cable system. FEM analysis for safety evaluation of the two bridges was conducted and the results were explained. The result could be used by operators and owners of bridges for the future maintenance and management.

Shield tunnel-shaft joint has caused problems in use which has different soil condition and boundary condition according to structure type. For solving this problems we developed joint reinforcing and inflow water cut-off system which can ensure stability of shield tunnel-shaft and reduce costs of maintenance.

There are bolt tightening torque decision standards in KSB 0101 for high tension bolt(torque calculation method) and in KSB 0140 for general bolts(general rule for bolt tightening torque decision), But in bolt torque decision general rule method, using Stainless bolt, friction coefficients between bolt and to-be-bolted object will rule the calculated yielding contraction axle force and yielding contraction torque, making it hard to determine the contraction torque in the field. So in other to help determine the contraction torque for stainless bolts(STS304) in field using high tension bolt torque decision method, the needed torque for stainless bolt(STS304) is calculated referencing high tension bolt torque decision method. And the calculated torque is planned to be compared to field test results.

Most of the apartment buildings to be remodeled are in the form of wall structures, and walls are very important structural members. When remodeling, there are cases where existing walls are demolished and new walls are installed. If a wall is newly installed, the continuity of the wall from the foundation to the top floor must be ensured. Some slabs prevents the vertical continuity of the reinforced wall. It is because the upper and lower wall reinforcing bars must be connected through the demolished slab and the concrete must be poured. Therefore, in this study, the method to secure the vertical continuity of the reinforced wall during the remodeling will be examined.

The non-welded building hardware method can reduce accidents caused by welding, and can be constructed by bolt assembly, which can reduce labor costs and shorten the construction period. The purpose of this study is to evaluate the behavior of joints of non-welded and welded of building hardware frame

In recent years, non-welded building hardware that can be installed by bolt assembly is used. However, there is a need for a method to compensate for the occurrence of buckling at the bolted portion at the time of construction. The purpose of this study is to evaluate the behavior of joints between steel square pipe and fastener.

Recently, a method of using blast furnace slag to reduce the amount of cement which generates a large amount of carbon dioxide during the manufacturing process has been studied. Blast furnace slag is a latent hydraulic property material and requires the use of alkali activator. However, alkali activator is expensive and have problems in use. Therefore, in this study, an alkali aqueous solution was used instead of an alkali activator. The alkaline aqueous solution used in this study was obtained by electrolysis of pure water and has strong alkalinity of pH12. As a result, we found that the use of alkali aqueous solution is effective in improving the reactivity of blast furnace slag.

In this study, flexural and tensile properties of pre-cast UHPC deck joints with surface treatment applied to fields were evaluated. It showed that all specimen set experimental variables satisfied sufficient resisting load efficiency and crack standard.

Recently, Advanced water treatment facilities with Ozone are being introduced domestically. However, waterproofing/corrosion prevention construction method of concrete structure for existing advanced water treatment makes waterproofing/corrosion prevention materials and concrete deteriorated because of strong oxidation of ozone. Therefore, in this study, It was evaluated in Permeability Evaluation of metal spraying coating.

The purpose of this study is to evaluate the tensile strength of GFRP and BFRP Rebar after exposure to environmental factors of deterioration (alkali, freezing -thawing) in order to present that as basic data for the application of FRP Rebar as concrete reinforcement. As a result, in the exposure of an alkali environment, the deterioration of fiber-resin was accelerated as the temperature increased, and it was found that there was an insignificant effect on freezing-thawing.

The conventional method for estimating compressive strength of concrete has been suggested by considering only 1 to 3 influential factors. In this study, seven influential mixture factors (Water-Cement Ratio, Water, Cement, Fly ash, Blast furnace slag, Curing temperature, and humidity) of papers opened for 10 years were collected at three conferences in order to know tendency of data. The purpose of this paper is to estimate compressive strength more accurately by applying it to algorithm of the Deep learning.

This study investigated the properties of lightweight foamed concrete by using surfactant and synthetic foaming agent, lightweight aggregate. The effects of foaming agent types and replacing ratio of lightweight aggregate on the compressive strength, density and pore structure of the concrete were investigated. This study showed the improvement of important properties of lightweight foamed concrete. Lower pore distribution and correspondingly higher compressive strength values were reached. Also, synthetic foaming agent had more positive effect on the strength of foamed concrete.

In this study, the chemical deformation of cement pastes was determined by chemical analysis. The specimen for FT-IR analysis was prepared in the form of fine powder by grinding before heating. As the temperature increased, the hydrates inside the cement paste tended to decrease.

The study was conducted to evaluate the latent heat properties of cement mortar with different contents of phase change material (PCM). The paraffin PCM with melting point of 44℃ used in this study. PCM was added in the mixture with contents ranged from 0 to 30%. Test results indicated that the heat storage performances of cement mortar were improved with increasing the content of PCM.

This paper describes the flexural characteristic of high strength steel fiber reinforced concrete (SFRC) prisms with different fiber tensile strength. All mixtures have specified compressive strength of 80 MPa and fiber volume fraction of 0.5% and 1.0%. In accordance with EN-14651, SFRC prisms were made and tested under bending loading. Test results indicated that steel fiber has no significant effects on compressive behavior of SFRC. However, flexural behavior of high strength SFRC was improved considerably with increase of fiber tensile strength.

The objective of this paper is to offer the feasibility of premixed type ternary blended aggregates using reject ash(RA), crushed sand(CS) and sea sand(SS) by studying fresh properties of the concrete. RA is varied from 2.5% to 10% with interval of 2.5% by weight of mixed aggregates. Test results indicates that the replacement of RA by mixed aggregates with low quality crushed sand and sea sand resulted in decrease of slump and air contents.

The purpose of this study was to analyze the influence of retarder, fiber and admixture on durability properties of repair mortar mixed MPC(Magnesia phosphate composite). The test results showed that the resistance to freezing-thawing and chloride attack of MPC repair mortar with fibers and fly-ash were greater than those of MPC repair mortar without fibers and fly-ash.

The degradation of concrete exposed to high temperature was evaluated by applying ultrasonic pulse velocity evaluation method which is one of the nondestructive tests of concrete. As a result, it is difficult to distinguish compressive strength of concrete and estimate residual compressive strength of concrete. However, it was confirmed that the higher the heating temperature, the lower the compressive strength and ultrasonic velocity of the concrete.