• 한국강구조학회 논문집
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• 제27권5호
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• pp.423-433
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• 2015

상 하부 스플릿 티 접합부는 보-기둥 모멘트 접합부로써 T-stub 플랜지의 두께, 고장력볼트의 게이지 거리, 고장력볼트의 개수 및 직경 등의 영향에 따라서 상이한 거동특성을 나타낸다. 상 하부 스플릿 티 접합부는 일반적으로 접합부에 작용하는 휨모멘트는 T-stub이 지지하고 전단력은 전단탭이 지지하는 것으로 이상화되어 설계되고 있다. 그러나 중 저층 규모의 강구조물에 상 하부 스플릿 티 접합부가 적용되는 경우, 작은 규격의 보 부재가 적용될 수 있기 때문에 보 웨브에 전단탭을 설치하지 못하는 경우가 발생할 수 있다. 이 연구는 이와 같이 보 웨브에 전단탭을 설치할 수 없는 기하학적 형상을 갖는 상 하부 스플릿 티 접합부가 충분한 전단력 지지능력을 갖도록 하는 접합부 상세를 제안하기 위하여 진행하였다. 이를 위하여 상 하부 스플릿 티 접합부에 대한 3차원 비선형 유한요소해석을 수행하였다.

• 콘크리트학회논문집
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• 제11권4호
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• pp.43-54
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• 1999

Shear tests are performed on four full-scale 12.5 m proto-type models, "least depth double tee," which are resulted from the optimization process. Domestic superimposed live load regulation, domestic material properties which is available to product. Korean building code requirements, construction environments and economy are considered as the main factors to establish the process. All of the specimens tested fully comply with the shear strength requirements as specified by ACI 318-95. The research has shown following results. 1) The development length requirement of ACI 318-95 does not seem a good predictor for the estimation of bond failure in a beam with the strands below the supports. 2) The load required for the first initial coner cracking in the dap end and first web shear cracking does not seem to have any relation with the dimension and shear strength of the section in the test beams. 3) The strand slip has a direct relationship with the web shear cracking. However, the coner cracking in the dap end does not give any help for the slip in anchorage. 4) Use of whole area for bearing steel at the bottom of dap end is desired for safe bearing pressure design in the precast prestressed double tee beams. 5) The deflection of beam influences directly on the amount of strand slip at the anchorage after initiation of it, and relationship between them are very linear.

• 한국강구조학회 논문집
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• 제24권3호
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• pp.279-287
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• 2012

상 하부 스플릿 T 접합부는 T-stub의 두께, 고력볼트 게이지 거리 등의 주요 변수 조합에 따라서 보통모멘트골조 혹은 특수모멘트골조에 적합한 접합부로 사용된다. 상 하부 스플릿 T 접합부가 안전한 구조거동을 발휘하기 위해서는 건축구조기준에서 규정한 층간변위각 및 접합부모멘트에 대한 요구사항을 만족하여야 한다. 이러한 요구사항 조건의 충족여부를 파악하기 위해서는 접합부의 회전강성 및 한계소성모멘트에 대한 예측이 필수적이다. 따라서 이 연구는 일차적으로 정적하중을 받는 상 하부 스플릿 T 접합부의 회전강성 예측을 위한 해석모델 제안을 위하여 진행하고자 한다. 이를 위하여 3차원 비선형 유한요소해석을 수행하였다. 제안한 해석모델의 적용 적합성은 기존의 해석모델 및 실험결과와 비교 검토하여 입증하였다.

• 건축구조
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• 제19권4호
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• pp.61-66
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• 2012

• KCI Concrete Journal
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• 제14권1호
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• pp.36-42
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• 2002

Flexural behaviors of the two typical precast beam sections (inverted tee and rectangular) for buildings were investigated and compared. The height of web in the inverted tee beam was generally less than half of beam depth to be adapted to that of the nib in the ends of double-tee where the total building height limited considerably. The inverted-tee beams were designed for a parking live load - 500kgf/$m^2$ and a market - 1,200kgf/$m^2$ from the currently used typical shape of a domestic building site in Korea. The area and bottom dimension of rectangular beams were the same as those of inverted tee beams. These woo beams were also reinforced with a similar strength. following results were obtained from the studies above; 1) the rectangular beam is simpler in production, transportation, and erection, and more economic than the inverted tee beam in the construction test for these two beams with a same dimension and a similar strength, 2) all of the beams considered in the tests were generally failed in values close to those of the strength requirements in ACI Provisions. The ratios of test result to calculated value are averaged to 1.04. One rectangular and one inverted tee beams failed in a value only 2-3％ larger than the estimated volue of the Strength Design Methool the results of the Strain Compatibility Method wire slightly more accurate than those of the Strength Design Method, 4) the maximum deflections of all of the beams under the full service loads were less than those of the allowable limit in ACI Code Provisions. The rectangular beams experienced more deflection then inverted tee in the same loading condition and failed with more deflection, and 5) the rectangular and inverted tee beams showed good performances under the condition of service and ultimate loads. However, one inverted tee beams with fm span developed an initial flexural crackings under 88％ of the full service load even though they designed to satisfy the ACI tensile stress limit provisions.

• Computers and Concrete
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• 제29권3호
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• pp.161-168
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• 2022

Bridges using double-tee (DT) girders from 12 m to 15 m are one of the good choices to improve accessibility in rural areas of the Mekong River Delta. In this study, nonlinear finite element method (FEM) analysis was conducted with different constitutive laws of materials. The FEM analysis results were compared to experimental results to confirm the applicability of the constitutive laws of materials for DT girders. A parametric study through FEM analysis was then conducted to investigate the effect of span lengths, top flange depths, and a number of prestressing tendons on the capacity of DT girders in order that propose DT girders for rural bridges. Parametric results showed that the top flange depth of a DT girder for rural bridges could be 120 mm. The DT girder with a span length of 12 m or 13 m could be used 16 tendons, while the DT girder with a span length of 14 m or 15 m could be set up with 20 tendons. The prestressed concrete DT girders based on FEM results can be suggested for the construction of rural bridges.

• Structural Engineering and Mechanics
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• 제82권1호
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• pp.69-79
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• 2022

This paper discusses the field testing of two single-span double-tee girder (DTG) bridges in South Dakota to determine live load distribution factors (LLDFs) and the dynamic load allowance (IM). One bridge had seven girders and another had eight girders. The longitudinal girder-to-girder joints of both bridges were deteriorated in a way that water could penetrate and the joint steel members were corroded. A truck traveled across each of the two bridges at five transverse paths. The paths were tested twice with a crawl speed load test and twice with a dynamic load. The LLDFs and IM were determined using strain data measured during the field tests. These results were compared with those determined according to the AASHTO Standard and the AASHTO LRFD specifications. Nearly all the measured LLDFs were below the AASHTO LRFD design LLDFs, with the exception of two instances: 1) An exterior DTG on the seven-girder bridge and 2) An interior DTG on the eight-girder bridge. The LLDFs specified in the AASHTO Standard were conservative compared with the measured LLDFs. It was also found that both AASHTO LRFD and AASHTO Standard specifications were conservative when estimating IM, compared to the field test results for both bridges.

• 콘크리트학회논문집
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• 제12권6호
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• pp.75-82
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• 2000

Flexural behaviors of two typical architectural precast beam sections ; inverted tee and rectangular - were compared and investigated. The heights of web in inverted tee beams are generally less than half of beam depth in building structures to accomodate the nib of double-tee where the total building height limited considerably. The inverted-tee beams are designed for parking live load - 500kgf/$\m^2$ and market - 1,200kgf/$\m^2$ according to the currently used typical shape in the domestic market building site in Korea. The bottom dimension and area of rectangular beams are same to those of inverted tee beams to compare the flexural behaviors of two beams. These two beams are also reinforced for similar strength. Four flexural tests are performed on two beams. Following results are obtained from the tests; 1) The rectangular beam is simpler in production, transportation, and election, and more economic than the inverted tee beam for these two beams with same dimension and similar strength. 1) The estimations of flexural strength of two beams by Strength Design Method and Strain Compatibility Method is fully complied with the result of tests. However, Strain Compatibility Method is slightly ore accurate than Strength Design Method. 2) Overall deflections of two type beam under the service loads are less than those of the allowable limit in ACI Code provision. 3) The rectangular beam is failed in large deflection (average 12.56mm large) than those of inverted tee beams. 4) The rectangular and inverted tee beams with 6m span develop initial flexural crackings under the 88% of full service loading even though they designed to satisfy the ACI tensile stress limit provisions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.345-348
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• 2008

최근 국내의 건설 현장에서는 새로운 건설환경 조성과 선진외국 기술의 유입으로 인하여 구조물의 경제적인 방법에 의하여 단기에 완성하도록 요구하고 있으며 구조물의 안전성에 대한 요구도 함께 증가하는 추세이다. 이러한 요구조건을 만족시키기 위한 대안으로 PSC공법을 적용하고 장경간구조물이 가능한 부재인 더블티 슬래브가 있다. 더블티 슬래브는 현장 조립시 상부에 덧침 콘크리트를 타설하여 시공하게 되어 있지만 덧침 콘크리트 타설시 슬래브 라인을 따라 상부에 균열이 발생한다. 상부에 발생한 균열은 구조적으로 문제는 없지만 구조물의 유지 보수에 있어서 방수로 인한 여러 가지 문제점을 발생 시킨다. 본 연구에서는 더블티 슬래브와 역티형 보 접합부 상부의 덧침 콘크리트에서 발생하는 균열을 억제하기 위한 실험을 실시하였으며 이에 대하여 논의하고자 한다.

• 콘크리트학회지
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• 제9권3호
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• pp.63-70
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• 1997