• Advances in concrete construction
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• 제10권5호
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• pp.455-462
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• 2020

This study investigated the effect of horizontal casting joints on the mechanical properties and structural behavior of sustainable self-compacting reinforced concrete beams (SCRCB). The experimental research consisted of two stages. The first stage used four types of concrete mixtures which were produced to indicate the effects of cement replaced with cement waste at 0%, 5%, 10%, and 15% by weight of cement content on fresh concrete properties of self-compacting concrete (SCC) such as, passing ability, filling ability, and segregation resistance. In addition, mechanical properties such as compressive, tensile, and flexural strength were also studied. The second stage selected the best mixture from the first stage and studied the effect of horizontal casting joints on the structural behavior of sustainable SCRCBs. The effect of horizontal casting joints on the mechanical properties and structural behavior were at the 25%, 50%, 75%, and 100% of sample height. Load deflection, failure mode, and theoretical analysis were studied. Results indicated that the incorporation of replacement with cement waste by 5% to 10% led to economic and environmental advantages, and the results were acceptable for fresh and mechanical properties. The results indicated that delaying the time for casting the second layer and increasing the cement waste in concrete mixtures had a great effect on the mechanical properties of SCC. The ultimate load capacity of horizontal casting joints reinforced concrete beams slightly decreased compared with the control beam. The maximum deflection of casting joint beams with 75% of samples height is similar with the control beam. The experimental results of reinforced concrete beams were substantially acceptable with the theoretical results. The failure modes obtained the best forced casting joint on the structural behavior at 50% height of casting in the beam.

• Steel and Composite Structures
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• 제1권3호
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• pp.295-312
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• 2001

The purpose of this paper is to propose a new type of steel reinforced concrete (SRC) beam-column joints and to examine the structural performance of the proposed joints, which simplify the construction procedure of steel fabrication, welding works, concrete casting and joint strengthening. In the proposed beam-column joints, the steel element of columns forms continuously built-in crossing of H-sections (${\Box}$), with adjacent flanges of column being connected by horizontal stiffeners in a joint at the level of the beam flanges. In addition, simplified lateral reinforcement (${\Box}$) is adopted in a joint to confine the longitudinal reinforcing bars in columns. Experimental and analytical studies have been carried out to estimate the structural performance of the proposed joints. Twelve cruciform specimens and seven SRC beam-column subassemblage specimens were prepared and tested. The following can be concluded from this study: (1) SRC subassemblages with the proposed beam-column joints show adequate seismic performances which are superior to the demand of the current code; (2) The yield and ultimate strength capacities of the beam-to-column connections can be estimated by analysis based on the yield line theory; (3) The skeleton curves and the ultimate shear capacities of the beam-column joint panel are predicted with a fair degree of accuracy by considering a simple stress transfer mechanism.

• 헤리티지:역사와 과학
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• 제56권4호
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• pp.24-37
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• 2023

본 연구는 2022년에 새롭게 보물로 지정된 앙부일구의 재질과 외형적 특징을 분석하였다. 국립고궁박물관, 국립경주박물관과 성신여자대학교박물관의 세 기관에서 소장하고 있는 보물 앙부일구는 그 재질, 규격, 형태(외형), 은상감 등 제작기법이 쌍둥이처럼 비슷하다. 이 세 점의 앙부일구은 구리: 아연: 납이 90.6: 6.0: 1.8의 비율인 황동으로 제작되어 있다. 이 성분비는 82.2: 3.7: 11.8의 조성비를 가지고 있는 보물 제845호 앙부일구와 분명한 차이를 보인다. 새 보물 앙부일구에서 반구의 받침부분은 용의 문양이 수직기둥에 그려지고 구름의 문양이 기둥의 날개를 형성하여, 반구 지평환에 각각 리벳과 은땜으로 결합되어 있다. 이러한 운룡주(雲龍柱)의 문양은 조선 후기 제작된 다양한 앙부일구 받침대 중에서도 가장 뛰어난 조형미를 보여주고 있다. 앙부일구에 새겨진 북극고도는 1713년 이후에 제작되었음을 알 수 있는데, 실제 제작은 19세기 진주 강씨 앙부일구 전문제작자의 활동 시기에 근접할 것으로 추정된다. 본 연구가 2022년 지정 보물 앙부일구의 재질과 외형적 특징을 분석함으로써 근대 과학기기의 과학기술사적 고찰을 견인할 수 있기를 기대한다.