• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.2
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• pp.189-196
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• 2000

The objective of this paper is to propose an analysis technique to predict the behavior of PC wall structures subjected to cyclic load. While PC wall panel is idealized by finite elements, the joints at which PC walls are connected each other are idealized by nonlinear spring elements. Axial and shear spring elements are developed for simulating shear, compression and tension behaviors of joints. The strength and stiffness of each spring elements we presented from the previous research results and incorporated into the computer program of DRAIN-2DX. The proposed analysis technique is evaluated by analyzing specimens previously tested and comparing with those. On the strength, stiffness, energy dissipation and lateral drift, analytical results show good agreements with test results. This means the proposed technique is effective to predict the response of the PC wall structures.

• Computational Structural Engineering
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• v.8 no.3
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• pp.113-122
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• 1995

The purpose of this study is to evaluate performance and safety of structures designed according to current seismic code or provisions (e.g., Uniform Building Code(UBC), NEHRP provisions, etc.) during lifetime of structures. The performance is represented in terns of reliability in this paper. To perform reliability analyses, a large number of time history response analyses for a given structure are usually required. In this study, to perform reliability analyses ground motions are generated based on nonstationary random process and structures are designed based on UBC. In this paper, responses of structures under a given earthquake is evaluated using dynamic nonlinear time history analyses and also an equivalent nonlinear system (ENS) with response scaling factors. The ENS system is described in the companion paper. Therefore, this paper evaluates the seismic performance of structures and also verify the accuracy of ENS.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.197-204
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• 2005

Multipurpose Floor Level Joint(MFLJ) is a new construction technology system which was developed in domestic. By using this system, it is possible not only to absorb the deformation at expansion joint due to shrinkages of concrete but also to make ease the floor leveling during the concrete casting at floor. The system consists of two elements, supporting devices and rails. Their structural capacities were verified through several experimental programs, such as compressive strength test of support and bending test of rail. The purpose of this paper is to evaluate the deformation absorbing capacity of the floor level joint. An experimental work was carried out to simulate the deformation condition at the joint and the test result was analyzed and evaluated. In addition, FEM analysis for expansion joint of typical building was also performed to predict the real behavior of MFLJ. The test results showed that MFLJ has sufficient deformation capacity required to act as expansion joint.

• Korean journal of applied entomology
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• v.25 no.1 s.66
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• pp.11-16
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• 1986

Local difference in post-overwinter developmental periods was investigated by incubating the overwintered larvae collected from 8 locations at $25^{\circ}C$ begining January 15 and February 15. Based on the 2nd incubation test, it was found that Chunseong colony had the shortest pre pupal period of 17.9 days, while Gwangsan colony had the longest 27.7 days. In general, prepupal period showed negative correlation with latitudes. Average pupal periods were not significantly different among colonies. Adult emergence period showed the same trend as prepupal periods. Chunseong and Pyeongtaeg colonies emerged faster than the other colonies and showed a single peak of adult emergence, while Nonsan, Iri, Gwangsan colony showed several peaks of adult emergence.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.5
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• pp.721-731
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• 2018

Manpower in domestic construction sites is becoming more and more aging. Various methods have been devised to prevent productivity and quality deterioration of construction due to absence of skilled workers and difficulty in supplying manpower. Especially, many researchers study various methods such as Machine Guidance (MG) and Remote Machine Control to improve productivity and quality. Although many prior studies have been conducted since the advent of MG, There is lack of field test in a difficult site to stakeout. In this study, field test of MG excavator was carried out at difficult site to stakeout, and productivity analysis and quality evaluation were conducted. As a result of the analysis of productivity, the minimum value was 20.5%, the maximum value was 56.9%, and the average productivity in 4 days was 38.3% higher than the standard product. As a result of the analysis of quality, the horizontal error ${\pm}1cm$ and the vertical error ${\pm}2cm$ confirmed in the previous study were verified.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.321-330
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• 2002

This paper presents the experimental results of composite basement wall in which H-pile and reinforced concrete wall are combined using shear connector Twelve specimens are tested to evaluate the shear capacity of the wall. Main variables in the test are composite ratio, distribution of shear connector, thickness of wall, shear-span ratio, and shear reinforcement. Test results indicate that the shear capacity of test specimens varies with the foregoing variables except the composite ratio. The results are compared with strengths predicted using the equations of ACI 318-99, Zsutty, and Bazant. Based on this investigation, a method for predicting the shear strength of composite basement walls is proposed.

• Journal of Environmental Health Sciences
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• v.18 no.1
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• pp.22-33
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• 1992

In Iri industrial area, Heavy metals in ait of the factories, 10 metal and 8 non-metal factories, were examined for ten months(from Feb. to Nov, 1991). The methals in blood, urin and hair of 232 employees who have worked in the factories were also examined at the same time The results are summarized as follows 1. Heavy metals Pb, Cd and Mn in the metal factories were 0.031mg/m$^{3}$, 0.0065mg/m$^{3}$, and 0. 035mg/m$^{3}$ respectively, but 0.017mg/m$^{3}$, 0.021mg/m$^{3}$ and 0.014mg/m$^{3}$ in non-metal factories. 2. Heavy metals such as Pb, Cd and Mn in blood from employees in the metal factories were measured : 22.36$\mu$g/dl, 0.27$\mu$g/dl and 1.26$\mu$g/dl respectively, The values in the non-metal factories were 19.84$\mu$g/dl, 0.21$\mu$g/dl and 1.24$\mu$g/dl. 3. Heavy metals such as Pb, Cd and Mn in urine from employees in the metal factories were measured 32.94$\mu$g/l, 0.16$\mu$g/dl, and 1.60$\mu$g/dl respectively, whereas the values in the non-metal factories were 28.79$\mu$g/l, 0.13$\mu$g/dl and 1.35$\mu$g/l. 4. Heavy metals such as Pb, Cd and Mn in hair from employees in the metal factories were measured 8.92mg/kg, 0.33mg/kg and 3.71mg/kg respectively, but 8.14mg/kg, 0.31mg/kg and 3.26 rng/kg in the non-metal factories.

• Korean journal of applied entomology
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• v.39 no.1
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• pp.13-19
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• 2000

This studies was carried out to investigate the natural enemies of citrus red mite, pononychus citri and seasonal occurrence of its major beneficial insects in Yuzu groves (Chonnam province) from 1996 to 1998. Natural enemies against citrus red mite were 9 species including Oligota kashmirica benifica, 0. yasumatsui, Stethorus punctillum, Chrysopa pallens, Propylea japonica, Orius sauteri, Scolothrips takahashii, Amblyseius womersleyi and one unidentified species of thrips (Family: Phlaeothripidae). Among them, Oligota kashmirica benzficu and Stethorus punctillum were found to be dominant species. 0 . kushmirica henifica had 4-5 generations from middle May to middle November with peak in early September. S. punctillum had 3 generations from late May to late October with peak of late June to middle July. Population dynamics between predator ( 0 . kushmiricu benifica and S. punctillum) and prey (Panonychus citri) were quite well synchronized until September but predator density was decreased abruptly after October.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.511-521
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• 2002

A simple numerical modelling technique is proposed for estimating the shear stress distribution in beams of framed tube structures with multiple internal tubes. The structures arc analysed using a continuum approach in which each tube is individually modelled by a tube beam that accounts for the flexural and shear deformations, as well as the shear lag effects. The numerical analysis of shear stress is based on the mathematical analogy in conjunction with the elastic theory By simplifying assumptions regarding the form of strain distributions in external and internal tubes, the shear stress distributions are expressed in terms of a series of lineal functions of the second moments of area of the structures and the corresponding geometric and material properties, as well as the applied loads. Previous studies for axial stresses and shear lag phenomenon are further developed lot the numerical analysis of shear stresses in the tubes. The simplicity and accuracy of the proposed method are demonstrated through the solutions of throe numerical examples.

• Computational Structural Engineering
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• v.10 no.4
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• pp.281-290
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• 1997

Current seismic design code is based on the assumption that the designed structures would be behaved inelastically during a severe earthquake ground motion. For this reason, seismic design forces calculated by seismic codes are much lower than the forces generated by design earthquakes which makes structures responding elastically. Present procedures for calculating seismic design forces are based on the use of elastic spectra reduced by a strength reduction factors known as "response modificaion factor". Because these factors were determined empirically, it is difficult to know how much inelastic behaviors of the structures exhibit. In this study, lateral strength required to maintain target ductility ratio was first calculated from nonlinear dynamic analysis of the single degree of freedom system. At the following step, base shear foeces specified in seismic design code compare with above results. If the base shear force required to maintain target ductility ratio was higher than the code specified one, the lack of required strength should be filled by overstrength and/or redundancy. Therefore, overstrength of moment resisting frame structure will be estimated from the results of push-over analysis.