• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.287-294
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• 2017

BIM technology has been used in the domestic AEC field since the middle 2000s. BIM has proved its worth in cutting-edge buildings, mega-buildings and freeform buildings in particular. Many freeform buildings could not be completed due to the low level of construction technique. However, many successful cases emerged after adopting digital technology, including BIM which encouraged architects to challenge freeform designs. The modeling software that can generate the freeform shape are not usually able to build the efficient BIM data type in the AEC industry. In this study a process model of the parametric freeform construction member generation and conversion to BIM data is shown and the prototype system is demonstrated.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.44-51
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• 2006

In this paper, we present a network-based integrated nesting system, that is adapted a current engineering concept. Generally, sheet cutting processes proceed in turn following an existing order In this study, however, the special characteristics of these processes were analyzed and the processes were redesigned with distributed design so that they could be operated in a client/server environment. Also, the necessary sheet material cutting processes, part CAD, nesting, part CAM, and NC post-processor capabilities, were implemented so that many workers could handle them all on the Web. Compared to existing commonly used systems, the developed system can provide integrated work environment for cutting automation, allow job collaboration between workers, and it has proved that it can shorten the standby time for work. By grafting computer system technologies to sheet material cutting automation field, this research expects to contribute to the enhancement of factory automation efficiency and productivity.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.1
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• pp.61-67
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• 2002

Sawdust, peat, and sawdust+peat were used as bulking agent in the compost production process using three different origin of manure; cow, pig, and chicken. The organic content and individual N, P, K content of the final manure compost were higher when peat or peat+sawdust were used to control the moisture. The carbon to nitrogen ratio and moisture content were low when peat or peat+sawdust were employed. In the case of cow and pig manure compost produced with peat or peat+sawdust, beneficial microorganism content was also higher than that of the manure samples produced with sawdust only. These results indicate that peat can be a useful component in the production of high quality manure compost.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.175-188
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• 2012

A parametric study for varying the radii of curvature is performed with a curved tub girder bridge having three continuous spans. The bracing forces of top lateral bracings from the results of numerical equations are compared to those of 3-dimensional finite element analyses. New modifying factors applicable in computing the nominal member forces of top lateral bracings were suggested. The numerical equations were derived based on one girder system, and it is shown that the numerical equations exhibit some errors compared with 3D FEA results. The main reason for this phenomenon lies on the number of girders. The twin girder system has an external cross-beam between inner and outer girder. It also has larger lateral stiffness than the single girder system. Finally, the distributions by the torsion, bending, distortion, and lateral loading of the top lateral bracing forces were presented in this paper.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.189-192
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• 2008

Most existing double tee systems have need to improve flexure and shear design at their flanges in the section. In order to solve this problem we have devised MTS(Multi-tee slab) system, which is composed of several T-beams and applied spandrel end beams at each slab unit. The application of spandrel end beams has an beneficial effect on the shear strength and force distribution of slab unit because they support the ribs in the transverse direction. Numerical analysis shows that the spandrel end beams increase the shear strength. This paper represents the analysis of shear strength in MTS system and the effect of the spandrel end beams on the system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.1
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• pp.69-84
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• 2002

In this papers, an analytical model which can simulate the post-cracking behavior and tension stiffening effect in a reinforced concrete(RC) tension member is proposed. Unlike the classical approaches using the bond stress-slip relationship or the assumed bond stress distribution, the tension stiffening effect at post-cracking stage is quantified on the basis of polynomial strain distribution functions of steel and concrete, and its contribution is implemented into the reinforcing steel. The introduced model can be effectively used in constructing the stress-strain curve of concrete at post-cracking stage, and the loads carried by concrete and reinforcing steel along the member axis can be directly evaluated on the basis of the introduced model. In advance, the prediction of cracking loads and elongations of reinforced steel using the introduced model shows good agreement with results from the previous analytical studies and experimental data.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.1
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• pp.11-23
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• 2010

A sacrificial member with aluminum foam of excellent energy absorption capacity was proposed for the protection of significant structures. Parametric studies of explicit finite element analyses were performed to investigate the pressure mitigation of close-range air-blasts. The scaled distance of the blast had a range of Z=0.48~0.95 and an empirical blast load function was utilized. The analytical parameters of the aluminum foam were density, thickness and the existence of a cover sheet. Analytical results showed that the transmitted pressure can be controlled to have a similar level of yield values of the foam by using a foam with low density and higher thickness. As the blast load increased, the sacrificial member needed to have higher density and thickness. A cover sheet of the foam clearly showed its effect on the wider distribution of blast pressure. It is necessary to determine the design parameters of sacrificial foams considering different energy dissipation capacities according to the scaled distance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.843-854
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• 2013

This paper presents experimental research work for the evaluation of ultimate flexural behaviors of prestressed concrete beams with a corroded tendon. In order to evaluate the effects of loss of prestress or loss of tendon area on the ultimate flexural strength of prestressed concrete beams, static load tests are conducted using five prestressed concrete beams. After exposing prestressing tendons in two test beams using 25mm drill bit, the exposed tendons were corroded using an accelerating corrosion equipment to simulate loss of tendon area. During the tests, steel strains, concrete strains and displacements at the center of test beams were measured, and acoustic emission measurements were conducted to detect wire fractures. Based on the test results, evaluation method for predicting flexural strength of prestressed concrete beams with corroded tendons is investigated. In addition, evaluation methods for predicting the existence of corroded tendons in post-tensioned prestressed concrete beams at service loads are discussed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.60-67
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• 2020

Recently, many studies have been conducted on the structural behavior of HPFRCC, but most of the studies focused on the flexural behavior while studies on the shear behavior are limited. In this study, a model has been developed to reasonably predict the shear strength of a HPFRCC beam without stirrups. To develop the model, a HPFRCC beam was simply idealized with upper & lower chords resisting bending moment and a web shear element resisting shear forces. Then, taking into the account of the tensile behavior of HPFRCC, the main diagonal compressive strut angle and shear stress of the web shear element were evaluated on shear failure. Then, the shear strength of the HPFRCC beam could be evaluated. For the verification of the proposed model, the predictions by the proposed model were compared with the test results of 48 HPFRCC beams exhibiting shear failure. The results showed that the proposed model reasonably predicted the actual shear strength with an average of 1.045 and CoV of 0.125. This study are expected to be useful for related researches and design of members or structures to which HPFRCC is applied.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.1
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• pp.15-22
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• 2011

Pultruded fiber reinforced polymeric plastic (PFRP) structural members may be one of attractive alternatives of the structural members in the civil engineering applications because of its many advantageous mechanical properties. However, they have relatively low modulus of elasticity and also cross-sections of structural shapes are composed of thin plate components such as flange and web. Therefore, structural stability is an important issue in the design of pultruded structural compression members. For the design of pultruded structural member under compression, buckling and post-buckling strengths of plate components may be taken into account. In the structural steel design following AISC/LRFD, in addition to the buckling strength, the nonuniform stress distribution in the section is incorporated with a form factor. In this paper, the form factor for the design of PFRP structural member under compression is investigated through the analytical study. Furthermore, the process for the determination of the form factor is suggested.