• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.106-116
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• 2024

Purpose: This paper conducts IoT and CCTV-based safety monitoring to analyze accidents and potential risks occurring at construction sites, and detect and analyze risks such as falls and collisions or abnormalities and to establish a system for early warning using devices like a walkie-talkie and chatbot service. Method: A safety management service model is presented through smart construction technology case studies at the construction site and review a relevant literature analysis. Result: According to 'Construction Accident Statistics,' in 2021, there were 26,888 casualties in the construction industry, accounting for 26.3% of all reported accidents. Fatalities in construction-related accidents amounted to 417 individuals, representing 50.5% of all industrial accident-related deaths. This study suggests implementing AI chatbot services for construction site safety management utilizing IoT-based health monitoring technologies in smart construction practices. Construction sites where stakeholders such as workers participate were demonstrated by implementing an artificial intelligence chatbot system by selecting major risk areas within the workplace, such as scaffolding processes, openings, and access to hazardous machinery. Conclusion: The possibility of commercialization was confirmed by receiving more than 90 points in the satisfaction survey of participating workers regarding the empirical results of the artificial intelligence chatbot service at construction sites.

• Korean Journal of Construction Engineering and Management
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• v.25 no.2
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• pp.56-68
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• 2024

A construction standard production rates system for the factory built and on-site installation phases of OSC (Off-Site Construction)-based precast concrete (PC) structures in apartment buildings was recently proposed to establish an objective cost standard (Lee et al., 2021). In addition, the Korean government has taken steps to improve the institutional foundation for the systematic calculation of PC construction costs such as revising construction standard production rates for major components that can be applied to the on-site installation phase of PC method. In this study, we analyzed the results of a field survey of apartment building PC structures and collected expert opinions to develop factory-built and on-site installation standard production rates that can be applied to apartment building PC method. We also propose directions for improving the standard production rates so that they can be applied to the site and component of apartment buildings by comparing them with the current standard production rates. This study also derived the cost characteristics and cost reduction measures of PC construction by calculating the construction costs using the developed rates and comparing the construction costs with the RC methods of apartment buildings of the same scale. The construction standard production rates for PC construction derived in this study are expected to contribute to the spread of PC construction by ensuring the objectivity and consistency of the results of PC methods cost estimation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.13-20
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• 2024

In this study, when subjected to in-plane shear such as a shear wall, the behavior characteristics of a concrete member using CFRP rebars were investigated when the longitudinal reinforcement ratio was kept constant at 2.96% and the transverse reinforcement ratio was changed from 0.30 to 2.98%. The evaluation was conducted based on MCFT theory and analyzed by comparison with the case of concrete members using steel rebars. When the reinforcement ratio ranged from 0.30 to 1.19%, concrete members employing CFRP rebars exhibited higher shear strength compared to those using steel rebars. In contrast, at high reinforcement ratios of 1.79 and 2.98%, it was observed that the shear strength of the member with CFRP rebar was lower compared to the member with steel rebar. Maximum shear strain was observed to be higher for members reinforced with steel rebars at lower reinforcing bar ratios, while for ratios of 0.97% and above, CFRP rebars resulted in higher maximum shear strain. As the reinforcement ratio increases, the use of CFRP rebar instead of steel rebar results in a greater increase in maximum shear strain. By analyzing the difference in strain in the reinforcing bar as well as the difference in principal strain in the element caused by differences in the mechanical properties of the steel rebar and CFRP rebar, the shear strength and shear strain when using steel rebar and CFRP rebar with different reinforcement ratios can be compared and analyzed.

• Korean Journal of Construction Engineering and Management
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• v.25 no.4
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• pp.34-44
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• 2024

In defense and military facility projects, adjustments to contract amounts due to design changes directly or indirectly affect factors such as increased construction costs and extended construction periods. Moreover, they can lead to differences of opinion and conflicts between the military and contracting parties. This case study analyzed the integrated management of defense and military facility projects by the Gyeonggi Southern Facilities Division, which oversees projects in Seoul and the southern Gyeonggi Province region for the Army, Navy, Marine Corps, and Air Force. Out of 388 completed projects, 103 cases with design changes were selected for analysis, aiming to ensure the reliability of data regarding the proportion of design changes in project completion. The study classified samples by the causes of design changes specified in the Ministry of Planning and Finance's contract regulations, assigning rankings based on the occurrence rates of each cause. Furthermore, it analyzed detailed factors for each cause of design change and derived implications to propose improvement measures. Considering the limited access to military primary data, this case study is expected to contribute to minimizing design changes in defense and military facility projects. Additionally, it is anticipated to be practically useful for subsequent research on contract amount adjustments resulting from design changes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.133-144
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• 2006

In order to catch out such Bond Strength, the preceding researchers had ever examined the Bond Strength of FRP Plate through their experimentations by setting up of various fluent. However, since the experiment for research on such Bond Strength takes much of expenditure for equipment structure and time-consuming, also difficult to carry out, it is conducting limitedly. This Study purposes to develop the most suitable Artificial Neural Network Model by application of various Neural Network Model and Algorithm to the adhering experiment data of the preceding researchers. Output Layer of Artificial Neural Network Model, and Input Layer of Bond Strength were performed the learning by selection as the variable of the thickness, width, adhered length, the modulus of elasticity, tensile strength, and the compressive strength of concrete, tensile strength, width, respectively. The developed Artificial Neural Network Model has applied Back-Propagation, and its error was learnt to be converged within the range of 0.001. Besides, the process for generalization has dissolved the problem of Over-Fitting in the way of more generalized method by introduction of Bayesian Technique. The verification on the developed Model was executed by comparison with the resulted value of Bond Strength made by the other preceding researchers which was never been utilized to the learning as yet.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.2
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• pp.149-160
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• 2024

Severe casualties and property damage are occurring due to urban floods caused by extreme rainfall. However, there is a lack of research on preparedness, appropriate estimation of flood damages, assessment of losses, and compensation. Particularly, the flood damage estimation methods used in the USA and Japan show significant differences from the domestic situation, highlighting the need for methods tailored to the Korean context. This study addresses these issues by developing an optimized flood damage estimation technique based on the building characteristics. Utilizing the flood prediction solution developed by the Korea Institute of Science and Technology Information (KISTI), we have established an optimal flood damage estimation technology. We introduced a methodology for flood damage estimation by incorporating vulnerability curves based on the inventory of structures and apply this technique to real-life cases. The results show that our approach yields more realistic outcomes compared to the flood damage estimation methods employed in the USA and Japan. This research can be practically applied to procedures for flood damage in urban basement residences, and it is expected to contribute to establishing appropriate response procedures in cases of public grievances.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.4
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• pp.56-68
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• 2024

This study aimed to derive the concept and types of school outdoor spaces in Seoul. The research results showed that the concept of school outdoor space can be viewed as an outdoor activity space in schools that secures the value of integrated public life and communal life, including "behavioral rights, walking rights, living rights, urban rights, landscape rights (viewing rights), and nature experience rights." It can also be defined as a basic educational space that reflects the value of education, which is the basic function of schools and the characteristics of the community. As a result of the analysis based on the general types of outdoor spaces, it was found that the outdoor spaces of Seoul schools can be divided into three major categories: walking space (movement function), educational space (educational activities), and rest and other spaces (other services). Based on this, outdoor spaces were categorized and subcategorized to serve as the basis for policy implementation. These classifications are characterized by 1) simplifying the classification of spaces by function into three (movement functions, educational activities, and other services) to enable the use of outdoor spaces for integrated purposes; 2) reflecting the complex use of spaces by subdividing educational spaces focusing on major activities, and in particular, discovering complex spaces due to the three-dimensionalization of buildings; and 3) enabling spatial-level planning and facility element-level access according to school characteristics. It is characterized by applying the recent trends and systems of general outdoor space projects to the current situation of schools.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.4
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• pp.104-119
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• 2024

The burden of medical expenses and the loss of social capital due to chronic diseases are becoming problems worldwide, and comprehensive and inclusive measures across various fields are required to prevent and manage their impacts. Social prescriptions have been shown to be effective in resolving the fundamental causes of health problems in patients with chronic diseases and in supporting existing treatments. In particular, green prescriptions that utilize the healing effects of nature and green spaces based on social prescriptions are being introduced in many countries overseas. Green prescription is the practice of a healthcare provider recommending activities in green spaces or experiences in the natural environment to patients for the prevention and management of chronic diseases. This study analyzed cases focusing on the policy system, the cases of the United Kingdom and the United States, which have introduced and operated green prescriptions under a national system. For this purpose, this study compared the background of green prescription introduction, related policies, and operation methods. Based on this, four implications were proposed to establish an effective plan for introducing green prescriptions in Korea. First, prior to establishing a policy for green prescriptions, interest in and research on green prescriptions are essential. Second, an implementation plan that fits the national health care system should be established, and policies should support the plan. Third, the introduction of green prescriptions from a long-term and gradual perspective is required. Fourth, comprehensive cooperation is required for the introduction and implementation of the green prescription system. This study can be used as basic data for discussion before introducing green prescriptions in Korea in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.179-186
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• 2006

In this study, Multi-Layer Perceptron(MLP) among models of Artificial Neural Network(ANN) is used for the development of a model that evaluates the bending capacities of reinforced concrete beams strengthened by FRP Rebar. And the data of the existing researches are used for materials of ANN model. As the independent variables of input layer, main components of bending capacities, width, effective depth, compressive strength, reinforcing ratio of FRP, balanced steel ratio of FRP are used. And the moment performance measured in the experiment is used as the dependent variable of output layer. The developed model of ANN could be applied by GFRP, CFRP and AFRP Rebar and the model is verified by using the documents of other previous researchers. As the result of the ANN model presumption, comparatively precise presumption values are achieved to presume its bending capacities at the model of ANN(0.05), while observing remarkable errors in the model of ANN(0.1). From the verification of the ANN model, it is identified that the presumption values comparatively correspond to the given data ones of the experiment. In addition, from the Sensitivity Analysis of evaluation variables of bending performance, effective depth has the highest influence, followed by steel ratio of FRP, balanced steel ratio, compressive strength and width in order.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.161-168
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• 2008

The freeze-thaw deterioration and chloride attack, which are the typical degradation factors for durability of marine concrete, are significantly affected by pore structures in terms of penetration and diffusion. These pore structures of concrete are closely related to the types and amount of AE agent, used to guarantee the resistance of freeze-thaw deterioration, and the elapsed time before concrete pouring. This paper evaluates the durability of concrete based on the results of tests on cylinder specimens and core specimens from mock-up members with different air content of 4~6% and 8~10%, respectively. According to the test results, the air content of hardened concrete is 2.5~5.2% at 7 days and 2.4~5.1% at 28 days. These air contents are about half of the initial values just after the concrete mixing. Judging from the amount of scale after the freeze-thaw test completed, air content of 8~10% is slightly more beneficial against the deterioration of concrete than air content of 4~6%. Meanwhile, the core specimens from mock-up members exhibit somewhat unfavorable freeze-thaw deterioration and chloride migration characteristic compared with the cylinder specimens tested in the laboratory under the same mixing condition, as to show 106% in freeze-thaw test and 160% in chloride diffusion coefficient test, respectively.