• 한국공간구조학회논문집
• /
• 제13권4호
• /
• pp.67-74
• /
• 2013

The Age-adjusted effective Modulus Method(AEMM) is one of the methods adopted for the construction stage analysis of concrete structures. The AEMM uses the aging factor to consider the effects of the varying concrete stress. In the aspects of computation time and the accuracy of the results, the AEMM is considered as one of most appropriate methods for construction stage analysis of tall building structures. Previous researches proposed appropriate values of the aging factor in the forms of graphs or using very simple equations. In this paper, an equation for estimating the aging factor as a function of rebar ratio in the section, compressive strength of concrete, notional member dimension, and age of concrete at the load application. The validity of aging factor proposed in this paper were examined by the comparison with the results of step-by step method.

• 한국강구조학회 논문집
• /
• 제16권6호통권73호
• /
• pp.807-818
• /
• 2004

콘크리트의 건조수축에 의한 합성거더의 장기거동을 평가하기 위해 수행한 실험과 이론적 분석방법에 대해 기술하였다. 합성거더를 제작하여 장기간 실내실험을 통해 콘크리트의 건조수축에 따른 합성보의 처짐, 곡률변화 및 변형률변화를 측정하였으며, 실험결과를 AEMM(Age-adjusted Effective Modulus Method)을 이용한 해석치와 비교하였다. 또한 콘크리트의 건조수축에 의한 합성거더의 장기거동에 영향을 미치는 여러 변수들에 대한 해석을 수행하였다. 실험결과 합성거더의 장기거동은 AEMM에 의해 적절히 평가할 수 있다는 것을 확인할 수 있었다. 합성거더의 콘크리트 단면에 커다란 인장응력이 발생하기 때문에 연속교 부모멘트부뿐만 아니라 단순교 정모멘트부에도 횡방향균열이 발생할 수 있다는 것을 보였으며, 횡방향 균열을 무시하는 경우 강거더에 작용하는 응력이 과대평가 될 수 있다는 것을 확인하였다. 이상의 연구결과를 토대로 콘크리트의 건조수축에 의한 합성거더의 장기거동 평가시 콘크리트 단면에 발생할 수 있는 횡방향균열을 고려하는 것이 합리적이라고 판단된다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2006년도 정기 학술대회 논문집
• /
• pp.490-495
• /
• 2006

The analysis method proposed by PCA is widely used in calculating the column shortening of reinforced and composite columns of a tall building. However, residual creep factor which relates creep strain of reinforced concrete to creep strain of plain concrete is based on Rate of Creep Method (RCM) which has theoretical defects and is considered obsolete. In this paper, a new equation for the residual creep factor based on Age-adjusted Effective Modulus Method (AEMM) which is considered exact and better than RCM is proposed. The residual creep factor by RCM is found to be higher than one by AEMM, which means current PCA method overestimates the shortening of a reinforced concrete column. By using the residual creep factor by AEMM, more exact column shortening of a tall building can be obtainable with a simple modification to PCA method.

• Steel and Composite Structures
• /
• 제42권5호
• /
• pp.671-683
• /
• 2022

To investigate and predict the long-term time-dependent behavior, such as creep, shrinkage, and relaxation of PS strands, and prestress loss in prestressed steel-concrete composite beams, named Precom, full-scale tests were conducted and the collected data were compared with those obtained from the two proposed analytical models. The combined effective modulus method (EMM)-empirical model proposed with a flowchart considered the creep effect to determine the prestress loss. Conversely, the age-adjusted effective modulus method (AEMM) with CEB-FIP equation was developed to account for the concrete aging. The results indicated that the AEMM with CEB-FIP model predicts the long-term behavior of Precom effectively.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.361-364
• /
• 2006

It is specified in KCI code that long-tenn deflection shall be determined by multiplying the immediate deflection by KCI code multiplier, unless it is obtained by a more comprehensive analysis. Therefore, in this study, the estimation method of long-term deflection by KCI code multiplier is known resonable by comparing analysis results using KCI code multiplier and AEMM.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
• /
• pp.175-176
• /
• 2009

본 연구는 설계단계에서 부등축소에 의해 수평부재에 발생하는 추가 내력을 예측할 수 있는 방법을 제안한다. 또한 EMM, AEMM을 활용하여 구한 유효탄성계수 및 재령보정 유효탄성계수를 수평부재에 적용하는 방법은 수평부재의 내력(모멘트)에 있어 정밀해석결과와 유사한 해석결과를 얻을 수 있었다.

• 한국농공학회논문집
• /
• 제46권2호
• /
• pp.29-37
• /
• 2004

An areal elderly migration model (AEMM) was developed to assess the demand of rural development projects targeted towards elderly people. The AEMM was developed with adaptation of the gravity model to represent spatial interaction regarding amenities. Areal characteristics were classified for estimating the amenities from the perspective of net migration. From 1990 to 2000, data were acquired from USCB, PASDA, PAHEALTH, PADCNR, PFBC, and NCDC in 67 Pennsylvania counties for analysis and application. The results revealed that elderly migration can be explained not only by areal characteristics but also by spatial interaction considering the population, distances, and amenities of surrounding areas.

• 셀메드
• /
• 제2권4호
• /
• pp.38.1-38.6
• /
• 2012

The present study aimed to determine the possible mechanisms of the peripheral antinociception of the aqueous extracts of Dicranopteris linearis (AEDL), Melastoma malabathricum (AEMM) and Bauhinia purpurea (AEBP) leaves in mice. Briefly, the antinociceptive profile of each extract (300, 500, and 1000 mg/kg; subcutaneous (s.c.)), was established using the abdominal constriction test. A single dose (500 mg/kg) of each extract (s.c.) was pre-challenged for 10 min with various pain receptors' antagonists or pain mediators' blockers and 30 min later subjected to the antinociceptive assay to determine the possible mechanism(s) involved. Based on the results obtained, all extracts exerted significant (p < 0.05) antinociceptive activity with dose-dependent activity observed only with the AEMM. Furthermore, the antinociception of AEDL was attenuated by naloxone, atropine, yohimbine and theophylline; AEMM was reversed by yohimbine, theophylline, thioperamide, pindolol, reserpine, and 4-chloro-DL-phenylalanine methyl ester hydrochloride; and of AEBP was inhibited by naloxone, haloperidol, yohimbine and reserpine. In conclusion, the antinociceptive activity of those extracts possibly involved the activation of several pain receptors (i.e. opioids, muscarinic, ${\alpha}_2$-adrenergic and adenosine receptors, adenosine, H3-histaminergic and $5HT_{1A}$, dopaminergic receptors).

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
• /
• pp.319-322
• /
• 2005

When a concrete structure is subjected to load, its response is both immediate and time dependent. Under sustained load, the deformation of a structure gradually increases with time and eventually may be many time greater than its instantanneous value. The gradual development of strain with time is caused by creep and shrinkage. On this study, to estimate of stress variations on time effects in partially prestressed concrete composite girder bridges, computer program applied Age-adjusted Effective Modulus Method(AEMM) in used.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.357-360
• /
• 2006

Under sustained load, the stress variation occurs due to creep and shrinkage of concrete on the sections of steel-concrete composite girders. In standard specification for highway bridge, the method of stress estimation considering time effects is based on the concept of Yassumi method. In this study, comparing the analysis results using the AEMM and Yassumii method long-term behaviors, the rationality of specified requirements is checked.