• Steel and Composite Structures
• /
• v.34 no.6
• /
• pp.837-851
• /
• 2020

This study aims to examine the interface shear behavior between precast high-strength concrete slabs with pockets and steel beam to achieve accelerated bridge construction (ABC). Twenty-six push-out specimens, with different stud height, stud diameter, stud arrangement, deck thickness, the infilling concrete strength in shear pocket (different types of concrete), steel fiber volume of the infilling concrete in shear pocket concrete and casting method, were tested in this investigation. Based on the experimental results, this study suggests that the larger stud diameter and higher strength concrete promoted the shear capacity and stiffness but with the losing of ductility. The addition of steel fiber in pocket concrete would promote the ductility effectively, but without apparent improvement of bearing capacity or even declining the initial stiffness of specimens. It can also be confirmed that the precast steel-concrete composite structure can be adopted in practice engineering, with an acceptable ductility (6.74 mm) and minor decline of stiffness (4.93%) and shear capacity (0.98%). Due to the inapplicability of current design provision, a more accurate model was proposed, which can be used for predicting the interface shear capacity well for specimens with wide ranges of the stud diameters (from13 mm to 30 mm) and the concrete strength (from 26 MPa to 200 MPa).

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.3
• /
• pp.143-155
• /
• 2016

Recently, the interest on applying AVM(Around View Monitoring) systems in construction equipments have been increasing due to the demand for better control, work efficiency and safety. Most of the existing AVM systems have been developed focusing on the application in automobiles and only several AVM systems have been developed for construction equipments. However, the original technology of AVM remained the same as in the automobiles that failed to consider the main properties of construction equipments and suggest appropriate range of AVM display (Top-view). Therefore, the purpose of this study is to suggest a pilot type of AVM system for construction equipment. Accordingly, literature review, deduction of main consideration factors, selection of sensors, system design, algorithm development of a pilot type of AVM system for construction equipment have been conducted. A laboratory experiment has also been conducted for the deduction of further improvements. As a result, a minimum image refresh rate of 20 fps has been achieved that clearly reflects the actual situation of the equipment and also, the actual motions of Boom, Arm, Bucket have been displayed appropriately on the AVM system based on the angle data collected by sensors. However, the experiment results have also shown that the following tasks still remain for future work: 1)Improvement of AVM image interpolation, 2)Development of calibration module for variety construction equipment.

• Journal of the Korean Society of Safety
• /
• v.28 no.5
• /
• pp.27-34
• /
• 2013

Almost accidents in construction sites are occurred by unsafe work conditions and failure making safe environment. As recent construction projects become more complex, various and diversified, So the potential of construction-related accidents is increased as well. Comparing the frequency of construction-related accidents in large-sized construction sites, small-sized construction sites are more vulnerable because of lack of workforce and less effective technology system. Furthermore, the absence of safety committee, poor financial condition leads to lack of safety education, installation of safety facilities, and provision of individual protective equipment, which indicates difficulties handling even basic safety management. Therefore, in order to lower the hazard rate at small-Sized construction sites, it is necessary to proceed with more structural and thorough actions for preventing accidents. In other words, it is necessary to analyze the causes of the accidents at small-sized construction sites, set criteria for safety management, and suggest safety management items according to work classification by evaluating the relative importance of the items.

• Safety and Health at Work
• /
• v.9 no.1
• /
• pp.53-58
• /
• 2018

Background: Since the Republic of Korea became a labor-force-importing country, the number of foreign workers has increased gradually, especially in the construction industry. The main objective of this study was to examine the differences in safety perception between domestic and foreign workers at Korean construction sites. Methods: A total of 891 Korean and foreign workers were surveyed: 140 foreign and 751 Korean workers. The general characteristics and 25 factors influencing safety perception were considered in the questionnaire. Regression and correlation analyses were conducted to examine the variables of workers' safety perception. Results: Differences of nationality (F = 7.379, p < 0.001) and workplace accidents were statistically significant for both domestic (F = 1.503, p < 0.05) and foreign workers (F = 7.868, p < 0.05). In contrast, age, education, and Korean language level were significant variables only for foreign workers. Correlation coefficients of $0.428^{**}$ for Korean and 0.148 for foreign workers between two items - namely, "management's commitment to safety" and "blaming staff when they make mistakes" - support the conclusion that foreign workers do not trust management's commitment to safety, while Korean workers have confidence in these commitments. Conclusion: Foreign workers' level of safety perception should rise to the same level as Korean workers, especially in terms of obeying safety rules, safety education performance, and safety beliefs. Therefore, an improvement plan for the Korean construction industry is suggested in order to have a better safety level at construction sites with foreign workers.

• Journal of the Korean Institute of Educational Facilities
• /
• v.25 no.6
• /
• pp.35-44
• /
• 2018

The purpose of this study is to predict more accurate construction costs and to support efficient decision making in the planning and design stages of smart education facilities. The higher the error in the projected cost, the more risk a project manager takes. If the manager can predict a more accurate construction cost in the early stages of a project, he/she can secure a decision period and support a more rational decision. During the planning and design stages, there is a limited amount of variables that can be selected for the estimating model. Moreover, since the number of completed smart schools is limited, there is little data. In this study, various artificial intelligence models were used to accurately predict the construction cost in the planning and design phase with limited variables and lack of performance data. A theoretical study on an artificial neural network and deep learning was carried out. As the artificial neural network has frequent problems of overfitting, it is found that there is a problem in practical application. In order to overcome the problem, this study suggests that the improved models of Deep Neural Network and Deep Belief Network are more effective in making accurate predictions. Deep Neural Network (DNN) and Deep Belief Network (DBN) models were constructed for the prediction of construction cost. Average Error Rate and Root Mean Square Error (RMSE) were calculated to compare the error and accuracy of those models. This study proposes a cost prediction model that can be used practically in the planning and design stages.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.610-613
• /
• 2003

Ensuring technical ability is essential in the construction industry to increase competitiveness in the global market. A new paradigm is coming up in academic education system to cultivate the competent engineers. The major objective of this research is to suggest a positive learning pattern In order to overcome the limitations of the passive learning style. A case study, technical upgrading with a tower crane, us explained in terms of active learning process, results, and evaluation of students' performance.

• International conference on construction engineering and project management
• /
• 2005.10a
• /
• pp.924-928
• /
• 2005

Formative assessment of student progress and attitudes is important to our continuous improvement process, but collecting and compiling the data is burdensome without access to computer tools. This research is to set up a mobile computer based lab that will enable faculty who teach in rooms without computers to use testing and survey tools. The technologies necessary to develop such system including wireless communication, World Wide Web (WWW), database, and mobile computing are investigated in this research. The real-time based formative assessment of student is proposed. A hardware configuration for real-time assessment is also presented in the research.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.1
• /
• pp.29-36
• /
• 2014

To meet changing education needs due to globalization, interdisciplinary convergence, and ICT development, it is necessary for engineering disciplines to provide student-centered education. Not only do teaching methods using ICT reproduce teaching contents in a digital format, but they are also expected to be effective media for constructive student-centered learning whereby learners build knowledge themselves. The aim of this study was to develop a tool for safety education using virtual reality technology. To achieve the objectives, the author defined the requirements and constraints of the tool, and implemented a 3D educational tool in a virtual reality environment. A pilot test with 10 students showed positive results.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.3
• /
• pp.65-75
• /
• 2020

In this study, the purpose of the study was to verify the relationship between the company's construction safety management system and workers' safety consciousness and safety observance behavior. A survey of 357 workers was conducted and a statistical analysis was performed using the SPSS 25.0 program. As a result, the following main results were obtained: First, it was found that supervisor's capability, inner construction safety management, construction safety education, and construction disaster evaluation have significant effects on the worker's safety consciousness. Second, it was revealed that the worker's safety consciousness had a significant positive effect on the safety observance behavior. Third, it was shown that supervisor's capability, inner construction safety management, construction safety education, and construction disaster evaluation have significant effects on safety observance behavior. In addition, this study confirmed that the management supervisor's ability to handle safety at the work site is the most important factor in safety management in order to enhance the worker's safety consciousness and safety observance behavior.

• Steel and Composite Structures
• /
• v.9 no.4
• /
• pp.349-366
• /
• 2009

The composite slim beam has become popular throughout Europe in recent years and has also been used on some projects in China. With its steel section encased in a concrete slab, the steel-concrete composite slim beam can provide the floor construction with minimum depth and high fire resistance. However, the design method of the T-shape steel-concrete composite beam is no longer applicable to the composite slim beam with deep deck for its special construction, of which the present design models are not available but mainly depend on experiences. The elevation of the flexural stiffness and bending capacity of composite slim beams with deep deck is rather complicated, because the influences of many factors should be taken into account, such as the variable section dimensions, development of cracks and non-linear characteristics of concrete, etc. In this paper, experimental investigations have been conducted into the flexural behavior of two specimens of simply supported composite slim beam with deep deck. The emphases were laid on the bonding force on the interface between steel beam and concrete, the stress distribution of beam section, the flexural stiffness and bending capacity of the composite beams. Based on the experimental results, the reduction factor of equivalent stress distribution in concrete flange is suggested, and the calculation method of flexural stiffness and bending capacity of simply supported slim beams are proposed.