In conventional construction practices, roof-parapet junction structures inevitably disrupt the insulation installation's continuity, leading to energy loss and thermal bridging. To address this issue, parapet thermal breaks were installed to interrupt the heat flow between the roof and the parapet, effectively preventing thermal bridging and energy loss and thereby reducing overall energy loss in buildings. This study equipped three experimental specimens with the developed parapet thermal breaks to verify their structural performance. These specimens were subjected to unidirectional loading under displacement-controlled conditions. The structural performance of these insulation structures was evaluated by comparing and analyzing the test results with corresponding analytical studies conducted using a finite element analysis program. In addition, five analytical models with varying parameters of the parapet thermal breaks were developed and compared against the baseline model. Consequently, the most efficient shape of the parapet thermal break was determined.
The cultural heritage of fortresses is often exposed to external elements, leading to significant damage from stone weathering and natural disasters. However, due to the nature of cultural heritage, dismantling and restoration are often impractical. Therefore, the stability of fortress cultural heritage was evaluated through non-destructive testing. The durability of masonry cultural heritages is greatly influenced by the physical characteristics of the back-fille material. Dynamic characteristics were assessed, and endoscopy was used to inspect internal fillings. Additionally, a finite element analysis model was developed considering the surrounding ground through elastic wave exploration. The analysis showed that the loss of internal fillings in the target cultural heritage site could lead to further deformation in the future, emphasizing the need for careful observation.
The aim of this study is to evaluate the possibility of damage to cultural assets resulting from vibrations generated by construction vehicle traffic. The cultural heritage's natural vibration frequency was determined to be 150Hz by measurement. The damping ratios were calculated as 4.7% using the logarithmic decrement approach and 4.3% using the half-power method. The vibration measurements obtained during vehicle operation indicated that, despite an increase in vehicle velocity of up to 15 km/h, the vibrations remained below the detectable level of 0.13 mm/sec. When the road is curved and the terrain is sloped, a suitable speed for vehicle operation was found to be around 17 km/h, at which point vibrations were seen. The highest recorded vibration amplitude at this velocity was 0.217 mm/sec, which remains below the stringent regulation limit of 2 mm/sec. Thus, it can be concluded that there is no actual harm caused by vibrations.
In this study, the structural performance of the specimen fabricated through 3D printing was evaluated through monotonic loading experiments analysis to apply to 3D printed structures. The compression and flexural experiments were carried out, and the experimental results were compared to the finite element model results. The loading directions of specimens were investigated to consider the capacity of specimens with different curing periods, such as 7 and 28 days. As a result, the strength tended to increase slightly depending on the stacking direction. Also, between the 3D-printed panel composite and the non-reinforced panel, the bending performance depended on the presence or absence of composite reinforcement.
This study aims to evaluate the structural safety of a structural thermal barrier, installed inside the structure of a building and performed the role of a load-bearing element and an insulation simultaneously, contributing to the realization of net-zero buildings. To ensure the reliability of the analysis model, the analysis results derived from LS-DYNA were compared with the experimental results. Based on the results shown through the flexural experiment, the reliability of the thermal cross-section insulation structure model for slabs was validated. In addition, the effect of the UHPC block on the load support performance and its contribution to vertical deflection was verified.
This study proposed a seismic reinforcement of RC columns with non-seismic details, a fiber reinforcement method of aramid sheets and MLCP (high elasticity aromatic polyester fiber material) with different characteristics, and 4 full-size column specimens and conducted experiments. The results show that a non-seismic specimen (RC-Orig) rapidly lost its load-bearing capacity after reaching the maximum load, and shear failure occurred. The RC column reinforced with three types of aramid did not show an apparent increase in strength compared to the unreinforced specimen but showed a ductile behavior supporting the load while receiving a lateral displacement at least 1.57 to 1.95 times higher than the unreinforced specimen. The fracture mode of the specimen, according to the application of lateral load, also changed from shear to ductile fracture through aramid-based reinforcement. In addition, when examining the energy dissipation ability of the reinforced specimens, a ductile behavior dissipating seismic energy performed 4 times greater and more stably than the existing specimens.
본 연구는 절화 도·소매업자의 판매 행태, 소비자의 소비 행태와 수입산 절화 및 국내산 절화 인식을 조사하여 국내산 절화 경쟁력 강화를 위한 자료로 제공하고자 수행하였다. 설 문 조사는 도·소매업자 102명을 대상으로 2020년 7월부터 9 월까지 진행하였고, 소비자는 200명을 대상으로 2020년 8월 24일부터 25일까지 진행하였으며, 수집된 자료는 빈도 분석, 대응표본 t-test, 다중반응 교차분석을 실시하였다. 도·소매업 자의 판매 행태 조사 결과, 국내산과 수입산 절화 모두 판매하 고 있는 비율이 높았고 판매 시 국내산 절화의 품질보다 수입 산 절화의 품질이 우수하다고 응답하였다. 소비자의 구매 행 태 조사 결과, 주로 선물 목적으로 구매하며 구매 시 내적 품 질(수명)과 외적 품질(형태, 질감, 색상)을 중요시 여기는 것으 로 나타났다. 또한 소비자는 절화 구입 시 원산지를 확인하지 않는 경우가 많았으나 동일 품종일 경우 국내산을 구매한다고 응답하였다. 도·소매업자와 소비자의 절화 인식을 비교한 결 과, 도·소매업자는 국내산 절화가 평범하고 한정적이며, 수입 산 절화는 독특하다고 인식하였으나, 소비자는 국내산 절화가 독특하지만 수입산 절화와 국내산 절화 모두에 평범하고 한정 적이라고 인식하였다. 이러한 판매자와 소비자간 인식 차이는 실제 국가별 절화 품질에 대한 정량적 연구와 국가별 절화에 대한 인식 조사 필요성을 제기한다.
Recently, cultural heritages in South Korea gain many interests of restoration and preservation from the government since many of that have been severely damaged during earthquakes. Many previous studies in both terms of experimental and analytical approaches have been done to examine structural behavior and decide appropriate methods of preservation. Being motivated by such researches, this research aims to investigate a religious stone pagoda dated back to the Goryeo Dynasty in Korea. The structure consists of a granite stone foundation and baked bricks, which resembles the shape of traditional pagodas. In order to examine the structural behavior of the pagoda, an analytical model is implemented using ANSYS, a comprehensive engineering simulation platform. For the time history analysis of the pagoda, several earthquake excitations are chosen and input to simulation modeling. Seismic response of the tower such as time domain, natural frequency, modal shapes and peak acceleration measured at each layer are presented and discussed. In addition, the amplification ratio of the tower is calculated from the accelerations of each layer to determine tower stability in accordance with Korean seismic design guide. The determination and evaluation of status and response of the brick tower by simulation analysis play an important role in the preservation of history as well as valuable architectural heritages in South Korea.
Many Korean domestic masonry structures constructed since 1970 have been found to be vulnerable to earthquakes because they lack efficient lateral force resistance. Many studies have shown that the brick and mortar suddenly experience brittle fracture and out-of-plane collapse when they reach the inelastic range. This study evaluated the seismic retrofitting of non-reinforced masonry with Hybrid Super Coating (HSC) and Cast, manufactured using glass fiber. Four types of specimen original specimen (BR-OR), one layered HSC (BR-HS-O), two-layered HSC (BR-HS-B), one layered HSC, and Cast (BR-CT-HS-O) were constructed and analyzed using compression, flexural tensile, diagonal compression, and triplet tests. The specimen responses were presented and discussed in load-displacement curves, maximum strength, and crack propagation. The compressive strength of the retrofit specimens slightly increased, while the flexural tensile strength of the retrofit specimens increased significantly. In addition, the HSC and Cast also produced a considerable increase in the ductile response of specimens before failure. Diagonal compression test results showed that HSC delayed brittle cracks between the mortar and bricks and resulted in larger displacement before failure than the original brick. The triplet test results confirmed that the bonding strength of the retrofit specimens also increased. The application of HSC and Cast was found to restrain the occurrence of brittle failure effectively and delayed the collapse of masonry wall structures.
This study evaluates safety assessment before and after repair of Seonamsa temple seungseon bridge, which refer to the representative Hongye bridge in Korea. In this approach natural frequency of the structure were considered in the modeling procedure. Trial & error method is applied to obtain the approximate natural frequency before and after retrofit construction. Stiffness of the actual structure was examined to account for the dynamic characteristics of Hongye bridge measured in the field and adjusting parameters in computer modeling. The safety and usability of the stone structure in terms of load bearing capacity and displacement were examined.
Tomb of King Muryeong, located in Sonsan-ri, was found vulnerable due to leakages during since the summer of 2016. This research aims to evaluate structural safety of the Tomb under the tumulus. Site surveys were conducted to find vulnerable inner parts. Structural safety assessment is presented based on both site survey results and analytical results obtained through FEM analysis using the ANSYS program. The underground structure was explicitly modeled to focus on two types of loadings: design loads and actual gravity loads. In general, the tomb does not show any critical deflection increase or damage through the analytical investigation. However, maintenance through continuous monitoring is necessary to prevent severe deflections and stress concentrations since the rigidity of the tomb materials are very vulnerable and likely to be reduced due to prolonged weathering and continuous rain leakage.
Yangjindang house, which is located in Sang-ju province of South Korea, is one of the special Hanok structures dated back to Joseon dynasty. This study aims to examine structural safety of the Yangjindang wood frame building considering dynamic parameters such as the natural frequency and damping ratio. The numerical model of the wood frame building is implemented using Midas Gen, especially the wood joint where column and beam were connected. The behavior of the actual frame building was compared with the modeling results. In addition, structure responses such as shear force, axial force, flexural moment and deflections were calculated and compared with the allowable limits. Numerical results show that, generally, despite of some local members shear failure, Yangjindang’s structural response does not exceed the limitation according to current standards.
The purpose of this study is to evaluate the structural safety of cultural altar since its bearing capacity has been questioned due to weathering damages and sectional defections. This evaluation process consists two stages; which the first is field investigation and the second is structural modeling and analysis. Based on field investigation, all of the structural members supporting the altar were carefully examined and all the findings were accounted for the development of the structural modeling using the Midas computer program. Using a 3D scanner, the weight of the Buddha statue was applied to the structural modeling. Then, according to the allowable stress design method of KBC2016, the structural safety was evaluated. Based on this result, replacements of several structural members were recommended to increase the structural safety and value of cultural property.