• 제목/요약/키워드: 보의 처짐

Search Result 266, Processing Time 0.027 seconds

Design Equation of a Coupled Beam to Limit Deflection of Modular Unit Structures (모듈러 유닛 구조물의 사용성 향상을 위해 연결된 보의 처짐 제한을 위한 설계식 개발)

  • Park, Ji-Hun;An, Seok-Hyun;Cho, Bong-Ho;Lee, Sang-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2007.11a
    • /
    • pp.471-475
    • /
    • 2007
  • Design equations of coupling plates, which connects floor beam of the upper modular unit and overhead beam of the lower one in order to improve serviceability in vibration, are proposed. End conditions of the coupled beams is semi-rigid and the optimal location of the coupling plates are assumed. Rotational constraints for both ends of the coupling plate modeled with beam elements are released and flexibility method is applied to obtain deflection equations of the coupled beam. Proposed equations are defined using the flexibility of the coupling plate, of which size can be determined inversely. Based on numerical analysis, coefficients of the design equations are calibrated and the revised equations are verified to be useful in the design of the coupled beam.

  • PDF

3층 규모 건물이 있는 콘크리트 플로팅 함체의 설계 연구

  • Lee, Yeong-Uk;Park, Jeong-A;Choe, Ji-Hun;Park, Tae-Jun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2012.06a
    • /
    • pp.419-421
    • /
    • 2012
  • 높이 2.5m의 콘크리트 플로팅 함체에 3층 규모의 상부골조가 있는 예제에 대해 동적 유체 해석과 정적 구조 해석을 수행하고 그 결과에 따라 종방향설계, 함체의 상부 및 하부 슬래브, 외벽 및 격벽에 대한 설계를 수행하였다. 환경 하중은 새만금 방파제 내부 정수역을 기준으로 파도주기 3.7초, 유의파고 1.0m와 풍속 40m/s를 적용하였으며, 하중조합은 ASCE/SEI 7-10을 기준으로 설계 하였다. 예제 구조물에 대한 설계 결과 고정하중에 의한 영향이 활하중 및 파랑하중에 비해 크게 나타났으며, 이로 인해 중앙부의 철근비가 높아지므로 고정하중을 감소시키는 방안을 검토하여야 함을 확인하였다. 또한 보의 지속하중에 의한 장기처짐과 추가적인 활하중에 의한 순간 처짐의 값이 허용 처짐값보다 크므로 보에서의 프리스트레싱을 고려해야 할 것으로 판단된다.

  • PDF

Support Deflection Effects in Slabs with Beam and Girder (보-거더 시스템 슬래브에서 지지부 처짐영향에 관한 연구)

  • 곽효경;송종영
    • Computational Structural Engineering
    • /
    • v.11 no.1
    • /
    • pp.237-249
    • /
    • 1998
  • In this study the support deflection effects in beam-girder slabs which are broadly being adopted in building structures are studied for both distributed loads and concentrated vehicle loads. Taking the finite element analysis of slabs supported with one or two cross beams, the member forces of slabs including the support stiffness have been calculated. Based on the obtained numerical results and regression analysis of those, correction factors of member forces for slabs supported with girders and cross beams have been proposed. Finally, the validity of the proposed correction factors are demonstrated through a typical design example.

  • PDF

Improved Static Element Stiffness Matrix of Thin-Walled Beam-Column Elements (박벽보-기둥 요소의 개선된 정적 요소강성행렬)

  • Yun, Hee Taek;Kim, Nam Il;Kim, Moon Young;Gil, Heung Bae
    • Journal of Korean Society of Steel Construction
    • /
    • v.14 no.4
    • /
    • pp.509-518
    • /
    • 2002
  • In order to perform the spatial buckling and static analysis of the nonsymmetric thin-walled beam-column element, improved exact static stiffness matrices were evaluated using equilibrium equation and force-deformation relationships. This numerical technique was obtained using a generalized linear eigenvalue problem, by introducing 14 displacement parameters and system of linear algebraic equations with complex matrices. Unlike the evaluation of dynamic stiffness matrices, some zero eigenvalues were included. Thus, displacement parameters related to these zero eigenvalues were assumed as polynomials, with their exact distributions determined using the identity condition. The exact displacement functions corresponding to three loadingcases for initial stress-resultants were then derived, by consistently combining zero and nonzero eigenvalues and corresponding eigenvectors. Finally, exact static stiffness matrices were determined by applying member force-displacement relationships to these displacement functions. The buckling loads and displacement of thin-walled beam were evaluated and compared with analytic solutions and results using ABAQUS' shell element or straight beam element.

A Prediction of the Long-Term Deflection of RC Beams Externally Bonded with CFRP and GFRP (CFRP와 GFRP로 외부 부착된 철근콘크리트보의 장기 처짐 예측)

  • Kim, Sung-Hu;Kim, Kwang-Soo;Han, Kyoung-Bong;Song, Seul-Ki;Park, Sun-Kyu
    • Journal of the Korea Concrete Institute
    • /
    • v.20 no.6
    • /
    • pp.765-772
    • /
    • 2008
  • For RC structures, long-term deformation occurs due to the inherent characteristics, which are creep and shrinkage. In terms of serviceability, it is important to limit deflection caused by the deformation to the allowable deflection. In the recent years, various repair and strengthening methods have been used to improve performance of the existing RC structures. One of the typical methods is FRP externally bonded method (EBR). Fiber reinforced polymer (FRP) has been used worldwide as repair and strengthening materials due to its superior properties. Besides, it has to offer improved strengthening performance not only under instantaneous load but sustained load. Therefore, accurate prediction method of deflection for the RC members externally bonded with FRP under sustained load is required. In this paper, three beams were fabricated. Two beams were externally strengthened with one of CFRP plate and GFRP plate respectively. Total three beams were superimposed under sustained load of 25 kN. During 470 days, deflections at midspan were obtained. Moreover, creep coefficients and shrinkage strains were calculated by using ACI-209 code and CEB-FIP code. In order to predict the deflection of the beams, EMM, AEMM, Branson's method and Mayer's method were used. Through the experiment, it was found that the specimen with CFRP plate has the most flexural capacity and Mayer's method is the most precise method to predict total long-term deflections.

Flexural Performance of Activated Hwangtoh Concrete Beam (활성 황토 콘크리트 보의 휨 성능)

  • Lee, Nam-Kon;Hwang, Hye-Zoo;Park, Hong-Gun
    • Journal of the Korea Concrete Institute
    • /
    • v.22 no.4
    • /
    • pp.567-574
    • /
    • 2010
  • As a eco-friendly material, Hwangtoh(red clay) has been studied for a partial or complete replacement of portland cement. Most of existing studies focused on the mechanical properties of the Hwangtoh concrete including the compressive strength, drying shrinkage, creep. In the present study, the flexural capacity of the beams made with the Hwangtoh concrete was tested. One of the concrete tested consisted of activated Hwangtoh replacing 20% of the cement. The other consisted 100% activated Hwangtoh replacing all the cement. The simple beams were tested under two point static loading. The flexural strength, cracking moment, deflection, and ductility were compared with those of the beams made with ordinary portland cement concrete.

Evaluation for Approximate Bending Moment Coefficients of Non-Composite Form Deck One-Way Slab considering Unequaled Elastic Deflection of Steel Beams (철골보의 부동탄성처짐을 고려한 비합성데크 일방향 슬래브의 근사적인 휨모멘트 계수 평가)

  • Kim, Ho Soo;Lim, Young Do
    • Journal of Korean Society of Steel Construction
    • /
    • v.18 no.3
    • /
    • pp.373-383
    • /
    • 2006
  • In a steel structural system, noncomposite form deck one-way slab is the plate element supported by four-edged steel beams with unequaled stiffness. However, design criterion has analyzed the one-way slab as the continuous beam. Because the end beams that support the one-way slab have elastic supports t hat cause different deflections according to the support conditions and locations, the bending moments corresponding to the support ic support effect is not considered in the design criterion. Accordingly, to conduct a reasonable estimation of approximate moment coefficients considering the unequaled elastic support conditions, this study analyzes and estimates various models with varia bles for the ratios of live load to dead load and pattern arangements of live loads and span lengths. The analytical methods considering the finite three-dimensional plate element, the two-dimensional elastic support and the infinite stifnes suport are performed.

Experimental and Numerical Study of Fire Resistance of Composite Beams (무피복 합성보의 내화성능에 대한 실험 및 해석적 연구)

  • Ahn, Jae Kwon;Lee, Cheol Ho
    • Journal of Korean Society of Steel Construction
    • /
    • v.27 no.2
    • /
    • pp.143-153
    • /
    • 2015
  • In this paper, the standard fire resistance test under load and associated numerical study were carried out to evaluate the fire resistance of unprotected partially encased beams and slimfloor beams. The temperature evolution and the deflection increase of the composite beam specimens were investigated and the effects of the key behavioral parameters including the load ratio, the reinforcement, and the fire exposure were analyzed. The test results showed that the temperature rise of the partially encased beams and slimfloor beams is considerably slow compared to the conventional H-shape composite beams. Up to at least 90 minutes, the reinforcements in the partially encased composite beams maintained below the temperature at which the cold steel strength is sustained. Unprotected partially encased beams and slimfloor beams in the experimental program achieved the fire resistance more than 2 hours according to the limiting deflection criteria. This implies that unprotected partially encased beams and slimfloor beams can be very promising alternatives to enhancing the fire resistance of steel beams. This study also conducted the fully coupled thermal-stress analysis by using the commercial code ABAQUS to the thermal and structural behaviour of composite beams in fire. The numerical predictions provide acceptable correlations with the experimental results.

Effects of Flexural Rigidity of Center Tower in Four-Span Suspension Bridges (4경간 현수교에서의 중앙주탑 휨강성의 영향)

  • Gwon, Sun-Gil;Yoo, Hoon;Choi, Dong-Ho
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.34 no.1
    • /
    • pp.49-60
    • /
    • 2014
  • For simple and accurate analysis for behaviors of multi-span suspension bridges which are expected to be frequently constructed as strait-crossing bridges, the deflection theory as the peculiar theory of a suspension bridge can be applied. This paper performs a structural analysis for four-span suspension bridges using the deflection theory. Simply-supported beams with tension are used for girders and the deflections of the beams due to the vertical loads and moments at supports are calculated. The calculation is performed iteratively until the deflections satisfy the compatibility equations of cables. The results of the deflection theory analysis considering tower rigidity are compared with those of the finite element analysis for verification. Importance of the tower rigidity for four-span suspension bridges is confirmed using various compatibility equations of the cable due to variation of the constraint conditions between main cable and top of towers. In addition, the simple parametric analysis for variation of the center tower rigidity is performed.

Relationship between Crack Characteristics and Damage State of Strengthened Beam (보강된 보의 균열특성과 손상상태의 상관관계)

  • 한만엽;김상종
    • Journal of the Korea Concrete Institute
    • /
    • v.14 no.6
    • /
    • pp.805-812
    • /
    • 2002
  • The number of old concrete structure which needs to be strengthened has been increased. The repair and strengthening methods have to be determined based on the current status of the structure. Consequently the estimation method for the damage status of the structure has been desperately needed, but no studies have been tried to use the crack and deflection characteristics to estimate the damage status. In this study, the crack characteristics depending on load level were measured and analysed. The crack characteristics observed from 11 samples were compared with damage status, and load level, The crack characteristics examined in this study include crack number, crack length, crack range, crack interval, maximum crack length, crack area, and average crack length. The deflections were normalized based on yield deflection, and the relationship between the relative deflection and the standardized crack characteristics were compared. Among the crack characteristics, crack interval, crack area, crack range, and maximum crack length, have been showed a close relationship to the relative deflection. Therefore, if such crack characteristics are evaluated, the maximum load applied to the structure is believed to be estimated. if additional parameters such as size of specimen, strength of concrete and steel, and steel ratio are studied, the damage status of structure can be estimated more accurately.