• Structural Engineering and Mechanics
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• 제50권1호
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• pp.121-135
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• 2014

Stone masonry structures are widely used around the world, but they deteriorate easily, due to low shear strength capacity. Many techniques have been developed to increase the shear strength of stone masonry constructions. The aim of this experimental study was to investigate the performance of stone masonry walls strengthened by metal connectors as an alternative shear reinforcement technique. For this purpose, three new metal connector (clamp) types were developed. The shear strength of the walls was improved by applying these clamps to stone masonry walls. Ten stone masonry walls were structurally tested in diagonal compression. Various parameters regarding the in-plane behavior of strengthening stone masonry walls, including shear strength, failure modes, maximum drift, ductility, and shear modulus, were investigated. Experimentally obtained shear strengths were confirmed by empirical equations. The results of the study suggest that the new clamps developed for the study effectively increased the levels of shear strength and ductility of masonry constructions.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.234-235
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• 2019

In the stacking and pitching items of the stone masonry and demolition process presented by 2018's standard of estimate, 7 estimating standards are presented according to the depth of masonry stone, and it is presented that the quantity per unit increases as the depth of masonry stone grows. As a result of analyzing the application status in the site, it is shown that 2 or 3 stones are mainly used according to the stone sizes regardless of the depth of masonry stone, and that as the size of the stone becomes larger, the quantity per unit decreases due to the size per square meter(㎡). Also, in most of sites, machine construction is mainly carried out by excavators with clampers attached to them. Therefore, in the 2019's application standard of estimate, it is analyzed that the size is simplified down to 3 sizes reflecting the site application status and that it is revised as a standard reflecting the result that as the stone size becomes bigger, the productivity increases.

• Earthquakes and Structures
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• 제13권1호
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• pp.29-38
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• 2017

Stone masonry is one of the oldest construction types due to the natural and free availability of stones and the relatively easy construction. Since stone masonry is brittle, it is also very vulnerable and in the case of earthquakes damage, collapses and causalities are very likely to occur, as it has been seen during the last Italian earthquake in Amatrice in 2016. In the recent years, some researchers have performed experimental tests to improve the knowledge of the behaviour of stone masonry. Concurrently, there is the need to reproduce the seismic behaviour of these structures by numerical approaches, also in consideration of the high cost of experimental tests. In this work, an alternative simplified procedure to numerically reproduce the diagonal compression and shear compression tests on a rubble stone masonry is proposed within the finite element method. The proposed procedure represents the stone units as rigid bodies and the mortar as a plastic material with compression and tension inelastic behaviour calibrated based on parametric studies. The validation of the proposed model was verified by comparison with experimental data. The advantage of this simplified methodology is the use of a limited number of degrees of freedom which allows the reduction of the computational time, which leaves the possibility to carry out parametric studies that consider different wall configurations.

• Geomechanics and Engineering
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• 제31권1호
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• pp.31-52
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• 2022

Investigating and evaluating the long-term creep behavior of historical buildings built on seismic zones is of great importance in terms of transferring these structures to future generations. Furthermore, assessing the earthquake behavior of historical structures such as masonry stone bridges is very important for the future and seismic safety of these structures. For this reason, in this study, earthquake analyses of a masonry stone bridge are carried out considering strong ground motions and various water levels. Tokatli masonry stone arch bridge that was built in the 10th century in Turkey-Karabük is selected for three-dimensional (3D) finite difference analyses and this bridge is modeled using FLAC3D software based on the three-dimensional finite difference method. Firstly, each stone element of the bridge is modeled separately and special stiffness parameters are defined between each stone element. Thanks to these parameters, the interaction conditions between each stone element are provided. Then, the Burger-Creep and Drucker-Prager material models are defined to arch material, rockfill material for evaluating the creep and seismic failure behaviors of the bridge. Besides, the boundaries of the 3D model of the bridge are modeled by considering the free-field and quiet boundary conditions, which were not considered in the past for the seismic behavior of masonry bridges. The bridge is analyzed for 6 different water levels and these water levels are 0 m, 30 m, 60 m, 70 m, 80 m, and 90 m, respectively. A total of 10 different seismic analyzes are performed and according to the seismic analysis results, it is concluded that historical stone bridges exhibit different seismic behaviors under different water levels. Moreover, it is openly seen that the water level is of great importance in terms of earthquake safety of historical stone bridges built in earthquake zones. For this reason, it is strongly recommended to consider the water levels while strengthening and analyzing the historical stone bridges.

• 대한건축학회논문집:계획계
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• 제35권7호
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• pp.81-88
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• 2019

The purpose of this study is to investigate the relations between brick and stone brick pagodas in all classes of pagoda with their construction and shape. Research objects of this study are brick and stone brick pagodas of National Treasure and Treasure and masonry pagodas that are similar to brick and stone brick pagoda. This study includes checking preceding researches, drawing questions from these preceding researches, and finding answers from these questions. The results of this study are as follows. First, pagoda of Bunhwangsa Temple, the first pagoda in the Silla Dynasty, was built as a masonry pagoda, not a stone brick pagoda. Second, roofs of stone brick pagoda barrows from brick pagoda's techniques for performance of material and ease construction. Third, brick or stone brick pagodas' base have Type II that has low and extensive foundation with soil and stones usually. Forth, Korean pagodas are categorized by their materials, construction methods, and shapes. Wooden pagodas, stone pagodas, and brick pagodas are categorized by materials, post-and lintel pagodas and masonry stone pagodas are categorized by construction methods, and pitched roof pagodas and terraced roof pagodas are categorized by shapes. Fifth, masonry pagodas of Buddhism that have shape of multi-story building were developed from Doltap, traditional stone stack, and they advanced with brick pagodas and stone pagodas to terraced roof stone pagodas and post-and lintel base brick pagodas.

• 한국구조물진단유지관리공학회 논문집
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• 제9권3호
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• pp.161-168
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• 2005

홍예교랑에서 무사석 및 적심석이 구조적특성이나 내하력에 미치는 영향에 대해서는 아직도 제대로 연구된 바가 없다. 특히 대부분의 홍예형 구조들이 문화재로 지정되어 있어 실물테스트를 하는 것은 매우 곤란하다. 석조구조물의 동적특성을 파악하면 접촉면의 강성을 파악할 수 있으므로 구조해석시 유용한 정보를 구할 수 있다. 본 연구는 무사석 및 적심석이 없는 5개의 홍예구조물과 우리나라 18개 홍예교량의 동적특성을 비교 분석함으로써 무사석 및 적심석 유무에 따른 고유진동수의 차이를 규명하는 방법으로 수행되었다. 연구결과 줄눈에 모르타르를 사용하지 않은 홍예구조의 경간에 따른 고유진동수는 우리나라 홍예교의 고유진동수보다 현저히 낮은 것으로 조사되었으며, 이러한 사실을 통해 볼 때 무사석 및 적심석이 홍예교의 고유진동수를 높이는 역할을 함을 알 수 있다.

• Earthquakes and Structures
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• 제17권4호
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• pp.355-363
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• 2019

Masonry structures in the rural areas of Turkey often damaged due to moderate and big earthquakes. After every earthquake many scientists made field investigations on the earthquake performance of these structures and gave many useful information on construction techniques. However, the newly constructed masonry buildings are still not suitable for the suggested techniques, and they are still in danger against future earthquakes. Five moderate earthquakes of moment magnitude Mw 5.3, 5.3, 5.2, 5.0, and 5.3 struck the Ayvacik-Çanakkale District of Turkey between 6 and 12 February, 2017. More than a thousand of aftershocks were occurred and most of the masonry buildings in the villages nearby main shock epicenter were affected. The author went to the earthquake field and investigated the earthquake performances of masonry structures. This paper presents the recorded acceleration data, acceleration response spectra, and the seismological aspects of these earthquakes. Besides, case studies of damaged stone masonry buildings, and failure mechanisms are discussed with illustrated photos which were taken during the field investigations. It is concluded that the damaged masonry buildings were not designed and constructed properly in accordance with the Turkish building codes or similar specifications.

• Geomechanics and Engineering
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• 제13권2호
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• pp.255-267
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• 2017

Soft clay strata can suffer significant settlement or stability problems under building loads. Among the methods proposed to strengthen weak soils is the application of a stone masonry trench (SMT) beneath RC strip foundations (as a masonry pad-stone). Although, SMTs are frequently employed in engineering practice; however, the effectiveness of SMTs on the ultimate bearing capacity improvement of a strip footing rested on a weak clay stratum has not been investigated quantitatively, yet. Therefore, the expected increase of bearing capacity of strip footings reinforced with SMTs is of interest and needs to be evaluated. This study presents a two-dimensional numerical model using the discrete element method (DEM) to capture the ultimate load-bearing capacity of a strip footing on a soft clay reinforced with a SMT. The developed DEM model was then used to perform a parametric study to investigate the effects of SMT geometry and properties on the footing bearing capacity with and without the presence of surcharge. The dimensions of the SMTs were varied to determine the optimum trench relative depth. The study showed that inclusion of a SMT of optimum dimension in a soft clay can improve the bearing capacity of a strip footing up to a factor of 3.5.

• 농업과학연구
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• 제38권1호
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• pp.101-108
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• 2011

In forest work, working conditions are very hard to improve. The proper distribution of work time and good posture is believed to bring about direct improvements such as accident prevention. On this, this study has analyzed forest workers' posture and their working hours in order to improve their working conditions in stone channel work. Authors has chosen several core elements of stone channel work to focus on, which include stone masonry, excavation of bed, moving stone, directing work, choosing stone, and breaking stone. The ratio of real working time over total working time was shown as 84.6%. As for the time ratio of each elemental work over the real working time, the stone masonry was 60.4%, the directing work was 15.1%, moving stone was 12.1%, choosing stone was 7.1%, breaking stone was 3.3%, and excavation of bed was 2.0%. According to the analytical results provided by OWAS, the ratio of category III (Work posture has a distinctly harmful effect on the musculoskeletal system) has shown that moving stone turned out 65.2%, choosing stone was 61.5%, stone masonry was 46.1%, breaking stone was 14.3%, excavation of bed was 12.5% and directing work was 6.8%. Furthermore, the ratio of category IV (Work posture with an extremely harmful effect on the musculoskeletal system) has shown that excavation of bed turned out 37.5%, breaking stone was 28.6%, stone masonry was 27.3%, choosing stone was 7.7%, moving stone was 6.1% and directing working was 4.5%. These results are expected to be utilized for the improvement with respect to both working methods in the stone channel work and the workers' working posture.

• 한국공간구조학회논문집
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• 제11권4호
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• pp.61-69
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• 2011

우리나라의 석조문화재을 모델링할 때 불연속면을 갖는 구조재의 강성을 어떻게 규명하느냐가 매우 중요하지만 원형보존을 해야 하는 문화재의 특성상 이를 파악하기란 매우 곤란하다. 이를 위해 본 연구에서는 비파괴조사를 이용하여 고유진동수를 측정한 후, 시행착오법을 이용하여 측정된 고유진동수와 컴퓨터 모델링 해석을 통해 고유진동수를 비교함으로써 불연속면의 강성, 구조재의 탄성계수 등 숭례문 육축 구조를 이루는 재료의 구조적 물성을 추정하였다. 이를 통해 육축 문화재에 대한 컴퓨터 모델링 기법을 제시하고 육축구조물의 안전성에 영향을 미치는 요인을 분석하였다. 연구결과 적심석의 강성이 육축구조물의 안전성에 가장 큰 영향을 미지는 젓으로 분석되었다.