The purpose of this study is to present a plan for reducing noise between floors of apartment houses in Korea and to examine the method for evaluating noise blocking performance rating between floors. The definition of floor noise and classification method of floor noise can be described, and floor noise can be distinguished into lightweight impact sound and heavy impact sound. The wall-type structure, which is mainly adopted in domestic apartments, relatively transmits vibration caused by impact sources rather than using columns and beams, so noise problems between floors are relatively higher than systems using columns and beams. Three representative methods for reducing and blocking floor noise are described, and criteria for evaluating the effectiveness of floor noise reduction by each method are described. In addition, the method for noise reduction and blocking grades for each construction method currently applied in Korea was described, and as a result, it was judged that the domestic rating evaluation method was not suitable for the current domestic situation, and a new evaluation method and standard were needed.

Existing reinforced concrete (RC) building frames constructed before the seismic design was applied have seismically deficient structural details, and buildings with such structural details show brittle behavior that is destroyed early due to low shear performance. Various reinforcement systems, such as fiber-reinforced polymer (FRP) jacketing systems, are being studied to reinforce the seismically deficient RC frames. Due to the step-by-step modeling and interpretation process, existing seismic performance assessment and reinforcement design of buildings consume an enormous amount of workforce and time. Various machine learning (ML) models were developed using input and output datasets for seismic loads and reinforcement details built through the finite element (FE) model developed in previous studies to overcome these shortcomings. To assess the performance of the seismic performance prediction models developed in this study, the mean squared error (MSE), R-square (R2), and residual of each model were compared. Overall, the applied ML was found to rapidly and effectively predict the seismic performance of buildings according to changes in load and reinforcement details without overfitting. In addition, the best-fit model for each seismic performance class was selected by analyzing the performance by class of the ML models.

This study is an experimental study to evaluate the vehicle-protection performance of the reinforced F section of a concrete median barrier. To reinforce the strength performance and durability of the F section, the design strength of concrete was increased and a wire mesh was added. The reinforced F section was tested in an actual collision to verify the protection performance of the SB4 class(Impact Severity: 160kJ) concrete barrier. In the truck-crash test for strengthperformance evaluation, no damage or no sufficient scattering occurred to cause damage to a third party. In addition, the truck smoothly moved through an escape box after the collision. THIV and PHD, which are criteria for evaluating the occupant-protection performance, were measured at 75% and 64% of the limit, respectively, and were confirmed to provide good occupant-protection performance. The vehicle rotations after the collision were 12%–19% of the allowed limits.

PURPOSES : The purpose of this study is to introduce the development of M5 low-level lighting (LLL) with the necessity and justification, mainly the ecological traffic safety merits and the convenience and traffic efficiency of maintenance compared to the existing high mounted pole lightings. The basic photometric property of the developed facility is analyzed. The visual performance is analyzed in terms of visibility distance and subjective opinions from the subjects on several factors related to lighting performance. METHODS : The basic photometric properties of LLL were measured in a tunnel-shaped shield with a visibility meter (LMK 5 Color). The visibility distance between LLL and existing pole-based lighting was observed by 13 subjects under various weather conditions, such as dry, rainy, and wet conditions. In addition, the subjective opinions in terms of several pre-designed factors regarding lighting performance were surveyed. RESULTS : The developed M5 LLL satisfied photometric requirements such as average surface luminance, overall uniformity, and lane uniformity, as suggested by the lighting guidelines. More than 200 m of visibility distances were measured under normal weather conditions for both LLL and existing pole lightings. However, more than 200 m were observed under a wet surface and a rain intensity of 20 mm/h in the case of LLL, but visibility distance was reduced to 48.46 m in the case of pole lightings. A higher visibility distance was observed in the case of amber colored LLL. According to the results of the subjective opinion survey, all types of lightings had favored ratings, and the whitecolored LLL showed the highest ratings under normal weather conditions. However, existing pole lightings had unfavorable ratings under wet surface and rainy conditions, whereas the amber colored LLL had favorable ratings compared to pole lightings in terms of uniformity of illumination, glare, and psychological stability. CONCLUSIONS : The necessity of M5 LLL lies on the cost-effective application to the low standard roadways where the cost is always the main factor to consider in safety facilities and the ecological benefits of roadsides. The developed LLL satisfied the basic optical property suggested by the related lighting guidelines and showed higher performance in terms of visibility distance across various weather conditions compared to the existing high mounted pole lightings.

PURPOSES: In this research, an SB3-level roadside barrier for a highway transition zone that meets the newly established guide Installation and Management Guide for Roadside Safety Appurtenance is developed. Its performance is evaluated by a numerical simulation and real-scale vehicle impact testMETHODS: The commercial explicit dynamic software LS-DYNA is utilized for impact simulation. An FE model of a passenger vehicle developed and released by the National Crash Analysis Center (NCAC) at George Washington University and a heavy goods vehicle (HGV) model developed by the TC226/CM-E Work Group are utilized for impact simulation. The original vehicle models were modified to reflect the conditions of test vehicles. The impact positions of the passenger vehicle and truck to the transition guardrail were set as 1/2 and 3/4 of the transition region, respectively, according to the guide.RESULTS : Based on the numerical simulation results of the existing transition barrier, a new structural system with improved performance was suggested. According to the result of a numerical simulation of the suggested structural system, two sets of transition barriers were manufactured and installed for real-scale vehicle impact tests. The tests were performed at a test field for roadside safety hardware of the Korea Highway Corporation Research Institute.CONCLUSIONS: The results of both the real-vehicle impact tests and numerical simulations of the developed transition barrier satisfied the performance criteria, and the results of numerical simulation showed good correlation with the test results.

Recently, systematic management strategy and planning infrastructure is improved the efficiency of infrastructure maintenance are prepared. In this study, a overall rating software tool is developed for SOC facilities to enable rapid analysis results of complex process.

Infrastructure deterioration is becoming a major problem in Korea. For the purpose of establishing quantitative grounds to distribute government annual budget effectively in the area of infra structure maintenance. This study has performed a senior-engineer-oriented question investigation. This results can be used as a base data for the project that developing performance-based evaluation techniques for SOC structures.