The purpose of this study is to make a generalized analytical based on the proposed experiments on reinforced concrete(RC) partially infilled frames by U-type precast concrete(PC) wall panels with openings. RC frame and PC wall panels were connected with different strengths. Therefore, we developed modified strut-tie model(STM) with two seismic retrofitting specimens and conducted a nonlinear analysis by using a computer analysis program. Based on the test results, truss member of modified STM was designed, applying the strut-tie model theory of ACI 318M-11 Appendix- A. As a result, the modified STM analysis results were very similar to the experimental results. As a result of the load-displacement curve comparison, the failure load were similar within 5∼17% of error range. In particular, the experimental results and the results of modified STM analysis show that the failure behavior almost matched.

Cyclic loading test was performed on the partially infilled reinforced concrete(RC) frames by L-type precast concrete(PC) wall panels with the connections of two different strength. Based on the results of experimental test, the nonlinear analysis was practiced with modified strut-tie model(STM) method by using a computer program. Truss member of modified STM was designed, applying the strut-tie model theory of ACI 318M-11 Appendix-A. Modified STM was designed with two ways according to the test result. PC wall panel and RC frame were assumed to composite when push loading applied. The PC and RC structures were also assumed to behave non-composite and those two structures connected with link(top connector) when pull loading applied. The connection was designed by using elastic link of program. The results of analytical modified STM process generally conform to the experimental results. The failure load and the failure mode of the specimens could be predicted using modified STM. The ratio of failure load measured in specimens to analytical values were between 0.83∼1.16. The member or connection which was failed in experiment yield in the results of modified STM. The failure mode perfectly matched.

This report offers an economically reasonable seismic reinforcement to non-seismic mid/low reinforced concrete structures. Installed a slit in between the reinforced concrete frame and masonry infilled wall then inserted twist bar to prevent inversion and attached to the lower/upper beam. Confirmed the seismic reinforcement effect through static loading test. Total of 4 specimens were produced for the test, a masonry infilled wall without seismic reinforcement and with seismic slit or twist bar applied. As a result, applying the seismic slit and twisted bar was economically reasonable and seismic reinforcement effect was confirmed by showing stable failure, increase of maximum strength and yield displacement, increase of accumulated energy dissipation.

본 논문에서는 범용유한요소해석 프로그램인 ABAQUS를 사용하여 국내에서 사용되는 콘크리트벽돌을 조적채움벽으로 가진 철근콘크리트 골조를 대상으로 유한요소해석을 실시하였다. 해석대상은 순수골조, 채움벽의 두께가 0.5B인 골조, 두께가 1.0B인 골조의 3종류이다. 철근콘크리트 골조 및 채움벽의 재료특성은 재료시험 결과로부터 구하였으나 두께가 1.0B인 채움벽의 경우 벽돌의 쌓기방법의 차이에 의해 0.5B 두께의 실험체보다 4배 정도 증가된 인장강도를 사용하였다. 유한요소해석결과는 실험을 통해 구한 하중-변위관계 및 변위각에 따른 균열양상을 상당히 정확하게 예측하였다. 유한요소해석 결과의 분석을 통해 조적채움벽과 골조사이의 접촉응력 및 골조의 전단력과 휨모멘트를 산정하였다.

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were experimentally performed on one unreinforced beam-column specimen and two reinforced specimens with L-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of L-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D except for the equation to predict the concrete breakout failure strength at the concrete side, principally agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

This study aims at developing a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. Top shear connection of the PC panel was required to show the composite strength of RC column and PC wall panel. However, the strength of the connection did not influence directly on the ultimate loading capacities of the specimens in the positive loading because the loaded RC column push the side of PC wall panel and it moved horizontally before the shear connector receive the concentrated shear force in the positive loading process. Under the positive loading sequence(push loading), the reinforced concrete column and PC panel showed flexural strength which is larger than 97% of the composite section because of the rigid binding at the top of precast panel. Similar load-deformation relationship and ultimated horizontal load capacities were shown in the test of PR1-LA and PR1-LP specimens because they have same section dimension and detail at the flexural critical section. An average of 4.7 times increase in the positive maximum loading(average 967kN) and 2.7 times increase in the negative maximum loading(average 592.5kN) had resulted from the test of seismic resistant specimens with anchored and welded steel plate connections than that of unreinforced beam-column specimen. The maximum drift ratios were also shown between 1.0% and 1.4%.

이 연구의 목표는 학교 건물과 같은 저층 보-기둥 철근콘크리트 구조 건물에서 프리캐스트 벽패널을 사용한 새로운 내진보강 방법 을 개발하는데 있다. 1개의 무 보강 보-기둥 실험체와 U형 PC 패널로 보강한 2개의 보강 보-기둥 실험체에 대한 정적 이력 하중실험을 진행하 였다. 앵커 접합부 실험체는 전단 파괴될 것으로 해석되었고 철판 용접 접합부 실험체는 휨 파괴할 것으로 예측되었다. 실험체의 종국 내력은 상부 접합부의 전단 내력과 PC 패널 절곡 부 휨 위험단면에서 휨 내력 중 약한 것으로 결정되었다. 이 실험체에서, 한쪽 RC기둥이 가 하중(미는 실험 하중)을 받아 PC 패널 부재를 밀게 된다면, 다른 쪽 내부 수직부재는 상부 전단 접합부로부터 부 하중(당기는 실험 하중)을 받게 되어있었 다. 가 하중을 받는 2개의 부재는 합성 휨 거동이 지배적이므로 합성단면의 휨 내력이 실험체의 최종 내력을 결정하게 되지만, 이 경우 최종 내 력에 대하여 상부 전단 접합부 강도의 직접적인 영향은 없다고 볼 수 있다. 그러나 부 하중(당기는 하중)을 받는 RC 기둥과 PC 패널 부재는 비 합성 거동이 지배적이고 실험체의 최종 내력은 상부 전단 접합부 전단내력의 크기에서 직접 영향을 받는 것으로 파악되었다. ACI 318M-11 Appendix-D 앵커 전단설계에 기초한 전단내력 그리고 실험에서 얻은 최대하중을 적용하여 마이다스 젠 탄성설계에 의하여 계산한 전단 외력 에 대한 비교 해석결과는 실험결과와 일치하는 해석결과를 보여주었다.

이 연구의 목표는 학교 건물과 같은 저층 보－기둥 철근콘크리트 구조 건물에서 프리캐스트 벽패널을 사용한 새로운 내진보강 방법을 개발하는 것이다. 1개의 무 보강 보－기둥 실험체와 U형 PC 벽패널로 보강한 2개의 보강 보－기둥 실험체에 대한 정적 이력 하중실험을 진행하였다. 앵커접합 PR1-UA 실험체와 철판접합 PR1-UP 실험체는 무 보강 실험체보다 평균 2.8배(평균 591.8 kN)의 강도 증가를 보여 주었다. 최대 변위비도 1.4%에서 2.7%사이 값을 보여주었다. RC 골조 우측 상단에서 좌측방향으로 가력 할 때 우측에 있는 RC 기둥과 보강 PC 패널의 수직 요소는 완전 합성상태로 가정하였고, 좌측에 있는 RC 기둥과 PC 패널은 완전 비 합성 거동하는 것으로 가정하여 해석한 결과 전체적인 휨 거동은 실험 결과와 대체적으로 부합하는 것으로 판단되었다.

This study carried out a series of seismic tests to elucidate the difference of movements between two buildings with or without masonry infilled wall in reinforced concrete frames which have no quake proof plan. Both of the experimental buildings showed irreversible deformity at low drift ratio of 0.6%. The strength and stiffness of the building with masonry infilled wall were higher than those of the building without masonry infilled wall, while the ductility of the former being lower than that of the latter. Thus it led to more brittle tendency of the former.