• Title/Summary/Keyword: reinforced joints

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Comparative Analysis of Biomechanical Behaviors on Lumbar with Titanium and Carbon Fiber Reinforced PEEK Connecting Rods for Fusion Surgery (티타늄과 탄소 섬유 강화 PEEK로 구성된 요추 유합술용 연결봉의 의공학적 영향에 대한 비교 분석)

  • Seo, Hye-Sung;Kang, Hae-Seong;Chun, Houng-Jae
    • Composites Research
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    • v.34 no.3
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    • pp.186-191
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    • 2021
  • The lumbar spinal fusion is a treatment performed to restore the stability of the degenerated lumbar. In this study, the intervertebral discs between two or more segments are removed and a bone graft is inserted to harden the segments. The pedicle screw system is inserted to vertebral bodies to fix two or more segments so that they can be firmly fused. In this study, a total of 7 patient-specific lumbar finite element models were created and pedicle screw systems were installed. The connecting rods made of titanium and CFR-PEEK was inserted to the generated models. Finite element analysis was conducted for four representative spine behaviors and statistical analysis was performed to investigate the biomechanical effects by the material properties of connecting rods. The intradiscal pressure of adjacent segments and the range of motion of the joints of each segment were investigated. In the subjects who used CFR-PEEK instead of Ti for connecting rods, the intradiscal pressure of adjacent segments tend to decrease and the range of motion of each segment tend to increase. However, no statistically significant difference in tendency was observed under all loading conditions.

Evaluation on Flexural Performance of Steel Plate Reinforced GLT Beams (강판 보강 집성재 보의 휨성능 평가 연구)

  • Park, Keum-Sung;Lee, Sang-Sup;Kwak, Myong-Keun
    • Journal of Korean Association for Spatial Structures
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    • v.20 no.2
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    • pp.39-49
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    • 2020
  • In this study, we will develop a hybrid cross-sectional shape of steel inserted type glued-laminated timber that can improve the strength of structural glued-laminated timber and maximize the ductility by using steel plate with excellent tensile and deformation ability. A total of three specimens were fabricated and the flexural performance test was carried out to evaluate the structural performance of the steel inserted type glued-laminated timber. In order to compare the effect of steel inserted glued-laminated timber, one structural glued-laminated timber test specimen composed of pure wood was manufactured. In addition, in order to evaluate the adhesion performance of the steel inserted, one each of a screw joint test specimen and a polyurethane joint test specimen was prepared. As a result, all the specimens showed the initial crack in the finger joint near the force point. This has been shown to be a cause of crack diffusion and strength degradation. The use of finger joints in the maximum moment section is considered to affect the strength and ductility of the glued-laminated timber beam. Polyurethane-adhesive steel inserted glued-laminated timber showed fully-composite behavior with little horizontal separation between the steel plate and glued-laminated timber until the maximum load was reached. This method has been shown to exhibit sufficient retention bending performance.

Seismic Behavior of Nonseismically Detailed Reinforced Concrete Beam-Column Joints (비내진 상세를 가진 RC 보-기둥 접합부의 지진 거동)

  • Woo, Sung-Woo;Lee, Han-Seon
    • Journal of the Korea Concrete Institute
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    • v.15 no.6
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    • pp.894-901
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    • 2003
  • The objective of this study is to clarify the seismic capacity and the characteristics in the hysteretic behavior of RC structures with non-seismic detailing. Interior and exterior beam-column subassemblages were selected from a ten-story RC building and six 1/3-scale specimens were constructed with three variables; (1) with and without slab, (2) with and without hoop bars in the joint region, (3) upward and downward direction of anchorage for the bottom bar in beams of exterior beam-column subassemblage. The test results have shown; (1) in case of interior beam-column subassemblage, there is no almost difference between nonseismic and seismic details in the strength and ductility capacity; (2) the Korean practice of anchorage (downward and 25 db anchorage length) in the exterior joint caused the 10%∼20% reduction of strength and 27% reduction of ductility in comparison with the case of seismic details; and the existence of hoop bars in the joint region shows no effect in shear strain.

Experimental Investigations on the Fatigue Strength of the Submarine Pressure Hull (잠수함 압력선체의 피로강도에 대한 실험적 연구)

  • Kim, Uln-Yeon;Kim, Kuk-Bin;Jeon, Jae-Hwang
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.1
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    • pp.67-75
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    • 2010
  • Submarine and deep sea diving structures are generally designed based on their ultimate strength. Fatigue strength at welded joint must be also taken into account because working stress is increased due to the increasing of diving depth and using high yield steel. The pressure hulls of submarine are subjected to fluctuating compressive loading. But in addition to the calculated stresses, high residual tensile stresses at welded part have to be considered. The state of stress level of pressure hull is tensile at surface and compressive at deep diving depth. This paper presents the results of an experimental investigation on the crack initiation and growth at the weld toe of T welded joints of HY-100 steel plate under constant amplitude loading. It is also investigated the phenomenon of the fatigue failure and test methods. Fatigue tests have been using real scaled local structural models of full penetration T-welded joint, which is a part of the cylindrical shell structures reinforced by ring stiffeners. Several load ratios under constant amplitude loading are considered in the tests. Crack initiation and growth characteristics are examined based on the beach marks of the cracked section of the test specimens. A design stress-life curve including the design formula is suggested according to tested data.

A Study on Adhesion Characteristics of Co-cured Long Fiber Prepreg Sheet-Aluminum Hybrid Structures (동시 경화 장섬유 복합재료-알루미늄 혼성 구조물의 접착 특성 연구)

  • Lee, Sung-Woo;Chang, Seung-Hwan
    • Composites Research
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    • v.31 no.1
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    • pp.17-22
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    • 2018
  • Long Fiber Prepreg Sheet (LFPS) has the advantages of excellent production efficiency and formability for complex shapes compared to conventional continuous fiber reinforced composites. When fibrous composites are used with different materials, joining method is important because strength of the joining part determines the strength of the hybrid structure. In this study, the adhesive joint strengths of co-cured LFPS and aluminum were evaluated under various surface treatment conditions and environmental conditions (temperature and moisture conditions). Mechanical abrasion and plasma exposure were used for the surface treatment. The adhesive joints experienced various surface treatments were tested by using single lap joint specimens. Adhesive strengths under various conditions were compared and the most appropriate condition was determined.

A Study on the Response Modification Factor for a 5-Story Reinforced Concrete IMRF (5층 철근콘크리트 중간모멘트골조의 반응수정계수에 관한 연구)

  • Kang, Suk-Bong;Lim, Byeong-Jin
    • Journal of the Earthquake Engineering Society of Korea
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    • v.16 no.5
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    • pp.13-21
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    • 2012
  • In this study, the response modification factor for a RC IMRF is evaluated via pushover analysis, where 5-story structures were designed in accordance with KBC2009. The bending moment-curvature relationship for beams and columns was identified with a fiber model, and the bending moment-rotation relationship for beam-column joints was calculated using a simple and unified joint shear behavior model and the moment equilibrium relationship for the joint. The results of the pushover analysis showed that the strength of the structure was overestimated with negligence of the inelastic shear behavior of the beam-column joint, and that the average response modification factor for category C was 7.78 and the factor for category D was 3.64.

Bearing Strength of Concrete Column and Steel Beam Composite Joints (콘크리트 기둥과 철골 보 합성골조 접합부에서의 지압강도)

  • Kim, Byong-Kook;Lee, Won-Kyu;Choi, Oan-Chul
    • Journal of the Korea Concrete Institute
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    • v.15 no.3
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    • pp.417-424
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    • 2003
  • A bearing failure in RCS(Reinforced Concrete Column and Steel Beam) system is recognized as one of the distinct joint failure modes for the composite frames. Vertical and transverse reinforcement in addition to concrete are effective for better transfer of vortical forces through concrete bearing. To examine the effect of the vertical bars, tie bars, a U-type detail developed in this study and concrete confinement, local bearing tests were conducted using 22 small-scale concrete block specimens. Test results show that vertical reinforcement and tie bars mainly contribute to the bearing capacity. However larger amounts of tie reinforcement are required than those recommend from ASCE guidelines, to apply the nominal concrete strength as 2 fck over the bearing area. Cross ties are proved to be highly effective for resisting the vertical forces. Maximum bearing strength can be increased upto 2.5 fck . An accurate prediction model for bearing strength is proposed for better design of the composite Joint.

Materials and Methods in Usonian Automatic House System of Frank Lloyd Wright (라이트의 유소니언 오토매틱 주택 시스템에 나타난 재료 및 공법에 관한 연구)

  • Kim, Tai Young
    • Journal of the Korean Institute of Rural Architecture
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    • v.18 no.4
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    • pp.1-8
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    • 2016
  • This study is to investigate the meaning and value of Usonian Automatic House System(UAHS) of Frank Lloyd Wright in his later period, focused on materials, methods, and his thoughts. The results of this study are follows. UAHS was the outcome of moderate cost and prefab house which Wright had successively attempted after the early Prairie period. The construction was simple and comparatively cheap, but subsequent automatics were difficult and expensive to build. Nevertheless, it was sufficiently flexible to support a rather wide range of house designs. Concrete was the inert mass and a plastic material. Wright saw a kind of weaving coming out of it. He also saw a kind of concrete masonry, steel for warp and masonry units for woof in the automatic concrete block. The reinforced bars in hollowed joints of concrete block increased the safety factor and affected the expression of the construction through the stabilization they provided. But they did not give concrete block the capability of structural span. Standardization as the soul of the machine might be seen in UAHS. The concrete blocks were more cheap, lighter, and larger hollowed plain than textile blocks in 1920s. But the variety of pattern and different block types in the UAHS were achieved at some sacrifice of standardization. The repetitive nature of production was compromised for artistic goals. The sense of compromise was not maximized, however, because the units as installed looked far more repetitive than they actually were.

Shake-table tests on moment-resisting frames by introducing engineered cementitious composite in plastic hinge length

  • Khan, Fasih A.;Khan, Sajjad W.;Shahzada, Khan;Ahmad, Naveed;Rizwan, Muhammad;Fahim, Muhammad;Rashid, Muhammad
    • Earthquakes and Structures
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    • v.23 no.1
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    • pp.23-34
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    • 2022
  • This paper presents experimental studies on reinforced concrete moment resisting frames that have engineered cementitious composite (ECC) in plastic hinge length (PHL) of beam/column members and beam-column joints. A two-story frame structure reduced by a 1:3 scale was further tested through a shake-table (seismic simulator) using multiple levels of simulated earthquake motions. One model conformed to all the ACI-318 requirements for IMRF, whereas the second model used lower-strength concrete in the beam/column members outside PHL. The acceleration time history of the 1994 Northridge earthquake was selected and scaled to multiple levels for shake-table testing. This study reports the observed damage mechanism, lateral strength-displacement capacity curve, and the computed response parameters for each model. The tests verified that nonlinearity remained confined to beam/column ends, i.e., member joint interface. Calculated response modification factors were 11.6 and 9.6 for the code-conforming and concrete strength deficient models. Results show that the RC-ECC frame's performance in design-based and maximum considered earthquakes; without exceeding maximum permissible drift under design-base earthquake motions and not triggering any unstable mode of damage/failure under maximum considered earthquakes. This research also indicates that the introduction of ECC in PHL of the beam/column members' detailing may be relaxed for the IMRF structures.

Structural Capacity Evaluation of Hybrid Precast Concrete Beam-Column Connections Subjected to Cyclic Loading (반복하중을 받는 하이브리드 프리캐스트 보-기둥 접합부의 성능평가)

  • Choi, Hyun-Ki;Yoo, Chang-Hee;Choi, Yun-Cheul;Choi, Chang-Sik
    • Journal of the Korea Concrete Institute
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    • v.22 no.3
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    • pp.325-333
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    • 2010
  • In this study, new moment-resisting precast concrete beam-column joint made up of hybrid steel concrete was developed and tested. This beam-column joint is proposed for use in moderate seismic regions. It has square hollow tubular section in concrete column and connecting plate in precast U-beam. The steel elements in column and beam members were connected using bolt. Furthermore, in order to prevent the premature failure of concrete in hybrid steel-concrete connection, ECC(engineered cementitious composite) was used. An experimental study was carried out investigating the joint behavior subjected to reversed cyclic loading and constant axial compressive load. Two precast beam-column joint specimens and monolithic reinforced concrete joint specimen were tested. The variables for interior joints were cast-in-situ concrete area and transverse reinforcement within the joint. Tests were carried out under displacement controlled reverse cyclic load with a constant axial load. Joint performance is evaluated on the basis of connection strength, stiffness, energy dissipation, and displacement capacity. The test results showed that significant differences in structural behavior between the two types of connection because of different bonding characteristics between steel and concrete; steel and ECC. The proposed joint detail can induce to move the plastic hinge out of the ECC and steel plate. And proposed precast connection showed better performance than the monolithic connection by providing sufficient moment-resisting behavior suitable for applications in moderate seismic regions.