• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.295-303
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• 2023

South Korea has recently witnessed an increasing number of seismic events, leading to a surge in studies focusing on seismic earth pressures, as well as the attributes of geological layers and ground where foundations are established. Consequently, earthquake-resistant design has become imperative to ensure the safety of subterranean structures. The slurry wall method, due to its superior wall rigidity, excellent water resistance, and minimal noise and vibration, is often employed in constructing high-rise buildings in urban areas. However, given the separation between panels that constitute the wall, slurry walls possess limited resistance to seismic loads in the longitudinal direction. As a solution, several studies have probed into the possibility of interconnecting slurry wall panels to augment their seismic performance. In this research, we developed and evaluated a method for linking slurry wall panels using mechanical joints, including concrete-confined steel pipes and headed bars, through mock-up tests. We also assessed the constructability of the suggested method and compared it with other analogous methods. Any challenges identified during the mock-up test were discussed to guide future research in resolving them. The results of this study aid in enhancing the seismic performance of slurry walls through the development of an interconnected panel method. Further research can build on these findings to address the identified issues and improve the efficacy and reliability of the proposed method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.245-253
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• 2021

RC slab bridges account for the largest portion of deteriorated bridges in Korea. However, most RC slabs are not included in the first and second classes of bridges, which are subject to bridge safety management and maintenance. The highest damaged components in highway bridges are the subsidiary facilities including expansion joints and bearings. In particular, leakage through expansion joints causes deterioration and cracks of concrete and exposure of reinforced bars. Therefore, this study analyzed the effect of adhesion damage at expansion joints on the response of the deck in RC slab bridges. When the spacing between the expansion joints at both ends was closely adhered, cracks occurred in the concrete at both ends of the deck due to the resistance rigidity at the expansion joints. Based on the response results, the correlation analysis between displacements in the longitudinal direction of the expansion joint and concrete stress at both ends of the deck for each damage scenario was performed to investigate the effect of the occurrence of damage on the bridge behavior. When expansion joint devices at both sides were damaged, the correlation between displacement and stress showed a low correlation of 0.18 when the vehicles proceeded along all the lanes. Compared with those in the intact state, the deflections of the deck in the damaged case at both sides showed a low correlation of 0.34 to 0.53 while the vehicle passed and 0.17 to 0.43 after the vehicle passed. This means that the occurrence of cracks in the ends of concrete changed the behavior of the deck. Therefore, data-deriven damage detection could be developed to manage the damage to expansion joints that cause damage and deterioration of the deck.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.535-546
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• 2011

In this paper, semi-rigid elasto-plastic post-buckling analysis of a space frame was performed using various explicit arc-length methods. Various explicit arc-length methodsand a large-deformation and small-strain elasto-plastic 3D space frame element with semi-rigid connections and plastic hinges were developed. This element can be appliedto both explicit and implicit numerical algorithms. In this study, the Dynamic Relaxation method was adopted in the predictor and corrector processesto formulate an explicit arc-length algorithm. The developed "explicit-predictor" or "explicit-corrector" were used in the elasto-plastic post-buckling analysis. The Eulerian equations for a beam-column with finite rotation, which considers the bowing effects, were adopted for the elastic system and extended to theinelastic system with a plastic hinge concept. The derived tangent stiffness matrix was asymmetrical due to the finite rotation. The joint connection elements were introduced for semi-rigidity using a static condensation technique. Semi-rigid elasto-plastic post-buckling analyses were carried out to demonstrate the potential of the developed explicit arc-length method and advanced space frame element in terms of accuracy and efficiency.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.473-479
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• 2020

In this study, the structural experiment was conducted with two types of specimens to investigate the mechanical behavior of the column-rafter-purlin connection of an arch-type greenhouse under monotonic loading. Based on the experimental results, the flexural performance was analyzed for two types of connections, and connection classification was attempted. Type B showed 77% of flexural performance compared to Type A, and both types showed that the rigidity and flexural strength did not reach the level of the full rigid. The behavior of the column-rafter-purlin connection was dominated by local buckling due to deformation of the weld and fasteners. As a result of connection classification by AISC standard, both Type A and B connections showed a result that did not meet the rigid connection performance assumed during design, and were classified as simple connection. Therefore, the connection performance evaluation and classification results show that the greenhouse design should be made in consideration of connection performance and in order to design a reliable greenhouse structure, a study on establishing clear design standards for the greenhouse connection is necessary.

• Journal of Acupuncture Research
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• v.17 no.3
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• pp.125-139
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• 2000

Study of the fourteen meridians that include name of P'ung(風) point. The results were summarized as follows. 1. Pyongp'ung(秉風) is located middle of the supraspinatous fossa(Small intestine Meridian, 手太陽小腸經). we can cute the local area disease and also use to cure the pathway of the Arm greater yang small intestine which is attacked by P'ung(風) disease. 2. Yep'ung(翳風) is located behind the lobule of the auricle, in the depression between the mastoid process and the mandible(Triple Energizer Meridian, 手少陽三焦經). we can cure the local area disease especially hyper yang disease and also use to cure the pathway of the Arm lesser yang triple energizer which is attacked by P'ung(風) and Yo'l(熱) disease. 3. P'ungmun(風門) is located 1.5 chon beside the lower end of the spine of the second thoracic vertebra(Bladder Meridian, 足太陽膀胱經). we can cure the local area disease and also use to cure the pathway of the Leg greater yang bladder which is attacked by P'ung(風) disease. 4. P'ungbu(風府) is located 1 chon above the middle of natural line of the hair at the back of the head, in the depression below the occiptal protuberance(Governor meridian, 督脈). It connects (Liver meridian, 足厥陰肝經) and Yin Link Vessel(陽維脈). we can cure the rigidity and pain in head and nape which is related Yin Link Vessel(陽維脈). 5. P'ungshi(風市) is located on the lateral part of the thigh, 7 hon above the patella(From the greater trochanter to the knee joint is 19 chon, Gallbladder Meridian (足少陽膽經). we can cure the local area disease(leg, knee, etc). 6. P'ungji(風池) is located Below the occipital bone, in the depression on the outer part of the trapezius muscle(Gallbladder Meridian, 足少陽膽經) on a level with P'ungbu(風府) (Governor vessel, 督脈). we can cure the local area disease and also use to cure the pathway of the Leg lesser yang gall bladder which is attacked by P'ung(風) disease.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.438-443
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• 2022

In this study, the lateral loading test was performed to analyze structural performance of multi-span plastic greenhouse through full-scale experiment and numerical analysis. In order to analyze the lateral stiffness and stress, we installed 9 displacement sensors and 19 strain gauge sensors on the specimen, respectively, and load of l mm per minute was applied until the specimen failure. In the comparison between the full-scale experiment and the structural analysis results of a multi-span greenhouse with venlo-type roof according to bracing installation, there was a large difference in the lateral stiffness of the structure. By installing a brace system, the lateral stiffness measured near the side elevation of the specimen increased by up 44%. As the bracing joint used in the field did not secure sufficient rigidity, the external force could not be transmitted to the entire structure properly. Therefore, it is necessary to establish a bracing construction method and design standards in order for a greenhouse to which bracing applied to have sufficient performance.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.2
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• pp.181-190
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• 2001

Purpose: The aim of this study is to investigate the usefulness of intestinal ultrasonography (US) and upper gastrointestinal endoscopy in the early diagnosis of Henoch-Sch$\"{o}$nlein purpura (HSP) with the gastrointestinal (GI) symptoms preceding the emergence of the skin lesion. Methods: The clinical, intestinal US and upper gastrointestinal endoscopic records of 85 patients (88 cases) with GI symptoms relating to HSP presenting between January 1999 and April 2001 were reviewed. Results: 1) GI symptoms were observed in 52 cases (59%) and skin, joint, renal and scrotal manifestations were observed in 88 (100%), 64 (73%), 15 (17%), 3 cases (3%) respectively. 2) Out of 52 cases with GI symptoms, abdominal pain was observed in all cases (100%). Positive stool occult blood, nausea and vomiting, abdominal tenderness, melena or tarry stool, diarrhea, hematemesis, rebound tenderness and rigidity were observed in 28 (50%), 17 (33%), 17 (33%), 12 (23%), 6 (12%), 4 (8%), 1 (2%) and 1 case (2%) respectively in order of frequency. 3) Intestinal US examination was performed in 27 cases with HSP and GI symptoms (52 cases). Out of 27 sonographic examinations 22 showed abnormal findings. Thickening of the duodeno-jejunal wall was observed in 16 cases (73%). Free peritoneal fluid, enlarged mesenteric lymph node, ileus and abnormal gall bladder were seen in 8 (36%), 8 (36%), 4 (18%) and 1 case (5%) respectively. In three cases of HSP without GI symptoms, those changes were absent. 4) In all of five cases with HSP and GI symptoms, endoscopic study showed mucosal edema and multiple hemorrhagic erosions especially at the second portion of the duodenum. Biopsy specimens from the duodenum of 2 cases out of 5 endoscopic examinations showed acute inflammatory infiltrates in the mucosa with hemorrhage. 5) Both intestinal US and endoscopic studies were performed in 4 cases with HSP and GI symptoms simultaneously. Out of 4 those cases, 3 cases showed the thickened duodeno-jejunal wall on the intestinal US, which suggested erosive hemorrhagic duodenitis by endoscopic findings. Conclusion: The typical but nonpathognomonic intestinal US findings including the thickening of the duodeno-jejunal wall and upper gastrointestinal endoscopic findings including hemorrhagicerosive duodenitis, in children with GI symptoms, should be considered a manifestation of HSP, even in the absence of skin lesion.

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.441-448
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• 2014

From several researches, recently, it was found that using hollowed precast concrete (HPC) column made more compact concrete casting in joint region possible than using normal solid PC (Precast concrete) column. Therefore, the rigidity of joints can be improved like those of monolithic reinforced concrete (RC). After filling the hollow with grout concrete, however, it is expected that the HPC column behaviors like composite structure since PC element and grout concrete have different materials as well as there is a contact surface between two elements. These may affect the structural behavior and strength of the composite column. A compressive strength test was performed for the HPC column with parameter of hollow ratio for the case with and without grout in the hollow and the result is presented in this paper. The hollow ratios in the test are 35, 50 and 59% of whole section of column. Concentrated axial force was applied to top of the specimens supported as pin connection for both ends. In addition, finite element (FE) analysis was performed to simulate the failure behavior of HPC column for axial compression. As a result, it was found that the hollow ratio did not affect the initial stiffness of HPC filled with grout regardless of the strength difference of HPC and grout. However the strength was increased inversely corresponding to the hollow ratio. The structural capacity of HPC without grout closely related to the hollow size. Especially, the local collapse governs the overall failure when the thickness of HPC is too thin. Based on these effect, a suitable equation was suggested for calculation of the compressive strength of HPC column with or without grout. FE analysis considering the contact surface between HPC and grout produced a good result matched to the test result.