Membrane structure is a system that is stabilized by maintaining a tensile state of the membrane material that originally cannot resist the bending or pressure. Also, it is a system that allows the whole membrane structure to bear external loads caused by wind or precipitation such as snow, rain and etc. Tension relaxation phenomenon can transpire to the tension that is introduced to the fabric over time, due to the innate characteristics of the membrane material. Thus, it is important to accurately understand the size of the membrane tension after the completion of the structures, for maintenance and management purposes. The authors of this paper developed the new portable measurement equipment by using sound wave and measured the tension of pre-existing membrane structure for its maintenance by using the equipment. Through analyzing the measurement data, the authors propose the points that should be improved and the technical method for the new maintenance system of membrane tension.

In this study, to evaluate the performance of fire resistance of the mortar with magnesium hydroxide(MH) and aluminium hydroxide(AH) which has a RCC (Radiant Control Capability) as repair material to the steel structure, temperature evaluation of mortar was conducted by increasing 500°C in the furnace. The performance of RCC can decrease a temperature to external and internal mortar. As a result, it is confirmed that temperatures of mortar with magnesium hydroxide(MH) and aluminium hydroxide(AH) were more decreased than general mortar due to the RCC effect of MH and AH. Therefore, it can be possible to apply to a repair material at the steel structure.

As public service life of PSC bridges is on the increase, lots of effort has been devoted to verify safety of PSC bridges. On the safety of PSC bridges, effective prestress force is one of the most important factors. At the moment, however, indirect measurements are mostly employed to evaluate the effective prestress force during and after construction. In this study, performances of FBG and EM sensors, which can directly measure the effective prestress force, are tested and investigated.

During maintenance, we closely examined the reinforced section where concrete has cracked at the time of cable installation. We confirmed that there has not been any sight of new cracks or growth of existing cracks. For the following year of Investigation, we plan to conduct close inspection of the reinforced section.

The objective of this study is to develop a bridge maintenance system utilizing NFC(near field communication) technology and mobile devices to enhance maintenance efficiency. The system consist of web program and mobile application. Web program was developed using java programming language that is object-oriented, and mobile application was developed using hybrid app that runs inside of a native container and leverages the device’s web browser to display locally hosted HTML pages. In additionally, this system had been designed to improve system usability and on-site applicability for convenient GUI (graphic user interface) environment.

The existing domestic bridge has become deterioration with the increase of bridges to be managed. Therefore appropriate maintenance such as an inspection, diagnosis, repair, and rehabilitation is required to extend the service life of the bridge. The domestic and international cases of the maintenance budget for bridges were investigated and analyzed. As a result, surveyed countries represent maintenance cost as only accounting values without clear and accurate categorized maintenance items.

Based on IoT (Internet of Things) where its concept contains providing convenience to human life by connecting every objects around us, numerous projects have been done in civil engineering field. This paper has conducted the basic study on adopting IoT sensing technology and network system into harbor.

There are bolt contraction torque decision standards in KSB 0101 for high tension bolt( torque calculation method) and in KSB 0140 for general bolts(bolt torque decision general rule), But in using bolt torque decision general rule method, 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 determine the contraction torque for general bolts in field using high tension bolt torque decision method, the torque decision method for general bolt is proposed referencing high tension bolt torque decision method. And the field torque test is planned to verify the adaptability of the proposed method in the field.

When estimate Short Lenth External Tendon's tension by Vibration Measurement Method, We Consider Tendon's Boundary. This paper is a case about estimation of short lenth tendon's tension by using practical formula estimation and stiff string with clamped-clamped boundary conditions.

In the winter season, a many problems such as water leaks, icicles, etc. has occurred by freezing phenomenon at the road tunnels. Therefore, in order to reduce property damage caused by cold environment, it is necessary to establish a mechanism of freezing and thawing of tunnel structures. In this study aims to introduce the method for freeze damage reduction and suggest the plan for practical use of it.

Indices are selected for the evaluation of deterioration of coated steel, and an evaluation method is proposed for each index. The evaluation methods proposed in this study are then applied on the existing inspection data measured on site, and the correlation between the resulting evaluation scores and service life of the coating is derived statistically. This correlation called to as the deterioration model can be used to determine the performance grade for the durability of coated steel.

A study performs estimation of fatigue safety that is considering cross-sectional loss of cable by applying foreign regulatory review. Because of steel cable-stayed bridge cable`s corrosion which is occurred after construction completion more than 30 years. Analysis result, all cable members secure fatigue safety considering cross-sectional loss of cable.

This study is the measurement for fatigue cracks at U-Rib in the steel deck bridge. Thus, to analyze the causes and reinforcement methods through the measurement results. So the bridge will preserve the safety & usability and want to enhance the durability.

This study was conducted to build an emergency action plan (EAP) for cable-supported bridges in South Korea. First, accidents happened on Cable-supported bridges were investigated and categorized based on the types. Second, accident scenarios were built-up regarding the types. Two bridges were selected for planning the emergency action following the accident scenarios. The emergency action plan established in this study could be used for the management of cable-supported bridges in the future.

In this research, experiment and simulation plans for evaluating the performance of the cables used for cable-stayed type bridges is presented. 27 cables are prepared where each of the cables are introduced with either corrosion or/and fatigue damage. Then the acquired data is analyzed with the vibration characteristics to evaluate the performance of the cables subjected to the two damage types.

To properly maintain steel structures, it is important to investigate the corrosivity of structural member. In this study, atmospheric exposure tests were carried out for 1 year using monitoring steel plates (MSP). In addition, atmospheric corrosion environment were also monitored by temperature and humidity sensor, corrosion monitoring (ACM) sensors, etc.

This study investigates the pore structure of cement paste after exposing to elevated temperatures, up to 800°C. The variation of pore structure of each sample was monitored for 180 days by mercury intrusion porosimetry (MIP). Test results showed that the increase of heated temperatures causes the increase of the size and volume of pores, which is probably due to the dehydration of hydration products, such as calcium silicate hydrate and calcium hydroxide.

In this research, the influence of using the combined aggregate including low-quality aggregate of exploded debris and sea sand on the fundamental properties of concrete was experimentally evaluated. First, when the low quality aggregate was used as a combined aggregate for concrete, the required unit water content was decreased and the compressive strength was improved rather than the low quality aggregate was used solely.

In this research, the adverse effect of various oils when the mortar including fly ash was submerged into the oils. From the experimental results, the highest length and mass changing rates were observed when the mortar was submerged into the biodiesel and in the case of relative dynamic elastic modulus, soy oil and biodiesel caused the most decreasing. Additionally, the mortar with fly ash was influenced more than ordinary Portland cement when it submerged into the oil.

This paper describes the effects of tensile strength and aspect ratio of steel fiber on flexural behavior of high-strength SFRC notched beam. Test results indicated that flexural properties of SFRC improved with increasing in aspect ratio and tensile strength of steel fiber.