鋼보의 經濟的 斷面

柳又秀 東亞大學校 1964 東亞論叢 Vol.2 No.2

橋梁에 使用하는 各種보에 作用하는 휨모멘트에 對하여 抵抗斷面을 決定하는 力學的인理論을 要約하면 다음과 같다. (1)鐵筋콘크리-트 矩形보 바닥판(鐵筋콘크리-트造)은 單只 바닥판上에 載荷된 荷重을 主보에 傳達하며 바닥판 自重도 또한 荷重으로써 主보에 作用한다. 이때 主보에 作用하는 휨 應力에 對하여 壓縮力은 中立軸上部의 콘크리-트에 依하여 抵抗되며 引張力은 中立軸上綠에 配置한 鐵筋에 依하여 抵抗된다. 콘크리-트의 引張力은 "0"으로 假定하고 있으므로 中立軸以下의 콘크리-트는 抗張鐵筋의 位置를 確保하는 구실 外에 아무런 役割없이 自重만 增大시키고 있다. (2)鐵筋콘크리-트 T形보 鐵筋콘크리-트 矩形보의 바닥판과 主보가 1체가 되여 바닥판이 荷重을 主보에 傳達하는 以外에 主보의 一部로서 휨 壓縮力에 抵抗되는 것이다. 이 때 휨 引張力에 對하여는 矩形보때와 全혀 같다. (3)鋼Ⅰ型보 鐵筋콘크리-트 矩形보때와 같이 바닥판은 荷重을 主보에 傳達할뿐이며 全荷重에 依한휨應力은 全部主보인 Ⅰ型보에 依하여 抵抗된다. 휨 壓縮力은 中立軸上部의 斷面에 依하여 또 휨 引張應力은 中立軸下部의 斷面에 依하여 抵抗된다. 그런데 鋼道路橋示方書에 依하면 鋼材의 許容壓縮應力은 σ??=1200(㎏/㎠)或은 σ??=1200-0.4?? (㎏/㎠)이며 許容引張應力은 σ??=1200㎏/㎠로 되여 있음으로 對稱斷面은 非經濟的이다. (4)鈑 桁 이것은 Ⅰ型보와 全혀 같은 理論이다. 以上 (3),(4)의 境遇에있어서도 鐵筋콘크리-트 T形보에서와 같이 바닥판을 主보와 一체로 만들어 휨壓縮力의 全部또는 1部를 이 바닥판에 依하여 抵抗시키는 것을 合成桁이라하여 現今 많이 使用하고 있으며 이로 因하여 많은 鋼材가 節約되고 있다. 그런데 現今設計方法은 먼저 斷面을 假定하여 그最大應力이 材料의 許容應力과 一政如否를 檢算한다. 그러나 이를 爲하여는 數回의 反復을 必要로 한다. 여기서는 이러한 反復을 避하기 爲하여휨모멘-트를 爲主로 하여 鋼材斷面을 假定하지 않고 全혀 理論的으로 求하는 것이다. The dynamic theory of the bending moment in any kind of beam in a bridge decided by the resisting section is summarized as follows: Ⅰ. REINFORCED CONCRETE RECTANGULAR BEAM The salb only transfers the load to the main beam and that beams own weight acts as a load on the main beam. At such time the compressive stress acting against the bending stress on the main beam is resisted by the concrete of the upper part of the neutral axis and the tensile stress is resisted by the (iron reinforcements distributed to the lowest extremity of the neutral axis. Since the tensile stress of concrete is reckoned at zero (0), the concrete below the neutral axis has no function other than to determine the location of the tensile-resistings reinforcement except to increase its own weight. Ⅱ. REINFORCED CONCRETE "T"BEAM The reinforced concrete rectangular beam slab and the main beam become as one and aside from the slab's transfer of load to the main beam as part of the main beam it is a resistor of the bending compressive stress. Here the rectangular beam is exactly the same time with regard to the bending tensile stress. Ⅲ. STEEL "I"SHAPED BEAM Like the reinforced concrete rectangular beam time, the slab only transfer the main load to the main beam and all bending stress caused by the entire load is resisted by the"I"shaped main beam. Bending compressive stress is resisted by the upper section of the neutral axis or the bending tensile stress is resisted by the lower section of the neutral axis. However, according to the "ROADBRIDGE BUILDERS' OFFICIAL MANUAL, the allowable compres-sive stress of steel material is σ??=1200㎏/㎠ or σ??=1200-0.4?? (㎏/㎠) and since allowable tensile stress is σ??=1300(㎏/㎠) the symmetrical section is not economical. Ⅳ. PLATE GIRDER The plate girder theory is the very same as the "I" shaped beam theory. As in the above instances of (3) & (4) so with the concrete "T" beam, the slab is made one with the main beam and the bending compressive stress of all or of part of these is resisted by the slab called a composition girder which is much in use at the present and whereby much steel is being saved. However, the method of construction now being employed is to estimate the section and to check whether the maximum stress and the allowable stress of the materials are the same. However, for such cases there is need to figure the matter re-peatedly. Not to figure the bending moment of the steel section to avoid this repetition is to figure entirely theoretically.

固形 棄物의 再活用方案에 對한 硏究 : 釜山市를 中心으로

柳又秀 동아대학교 공과대학 부설 한국자원개발연구소 1978 硏究報告 Vol.3 No.1

Most of the garbage can be recyclable, Even the present reuse of garbage will give the following benifists in case it is more efficient and organized. 1. It eliminates the cause of secondary pollution which might be brought out by burning and burning garbage. 2. The possibility use of fertilizer and agricultural chemicals can be reduced. 3. About 2 billion won can be earned from only the garbage (kitchen refuse) in the whole area of Busan every year. 4. Therefore, to the poor natural resourcesed korea, the reuse of garbage can be hired as one of the ways to exploit the resources.

立體뼈대의 解析을 爲한 program 事例硏究

柳又秀 동아대학교 공과대학 부설 한국자원개발연구소 1975 硏究報告 Vol.1 No.1

A computer program is described for the first order elastic analysis of space frames. The structural analysis is based on stiffness method by WILLIAM WEAVER. The type of frame which cam be analyzed is quite general rigid frame consisting of straight prismatic members, but, it should not be contained internal hinge. The source program is written in the FORTRAN language, and a example is given to prove this program to be correct. And the detail of source program and the example is included in appendix.

레미콘(Ready mixed concrete)의 施工軟度 改善에 관한 硏究

柳又秀 동아대학교 공과대학 부설 한국자원개발연구소 1984 硏究報告 Vol.8 No.2

This study is analysis the effect which is influenced to the construction workability improvement of ready mixed concrete adding flowing materials (Lignal SP) through the results of practical site experiment from the results, we can find that the characteristics of flowing materials is as follows : 1. By adding the sp materials to the few specific water content hard consistency concrete, it can be changed to the flowing fine construction workability concrete. 2. It has not had influenced to the setting time compressive strength, bending strength of concrete. 3. The concrete added the flowing materials shortens the surface finishing time, and it can improve accuracys, because, it is able to decrease specific water content,and so, has move little bleeding than ordinary hard consistency concrete. 4. The concrete added s. p materials can decrease the crach of structure because of reducing the drying shrinkage limit. As the results, lignal s. p material is regarded as the very suitable one of Ready mixed concrete flowing admixtures.

對角線距離가 不變하는 Rahmen의 解法

柳又秀,嚴采永 동아대학교 공과대학 부설 한국자원개발연구소 1977 硏究報告 Vol.2 No.1

Fig. 1. shows deformations of two near arbitrary members of rigid frame in this report. A. general equation on of relative displacement of Diagonal joints is Δℓ=y_(m)/EK_(O)(F_(m)a_(m)/k_(m)+F_(m+1)a_(m+1)/k_(m+1)) If this displacement is "O", the equation transfer F_(m)a_(m)/k_(m)+F_(m+1)a_(m+1)/k_(m+1)=O By this process, we can make simple simultaneous equations that's demensions is end moment. Rigid frame can be analysed by solving this simultaneous equations.

韓國河川의 流出率과 流出指標로서의 洪水直前 流量

金熙鍾,柳又秀,金佳鉉,申東守,韓健模,全裕燦 東亞大學校 大學院 1984 大學院論文集 Vol.9 No.-

This paper is a study on relation between run-off ratio and antecedent discharge, run-off ratio and antecedent discharge per unit area, antecedent discharge and antecedent precipitation, by the data from the five major river basins in Korea and the small river basins in Pusan. The Nak-Dong rivers(An-Dong upper stream) f=0.4780+0.0124 ln qA r=0.99 qA=0.3368e0.1101R r=0.99 f=0.5793+0.0146 ln(qA/A) r=0.99 The Nak-Dong rivers except Ga-song station f=0.2017-0.0840 ln qA r=0.75 f=0.7012+0.0750 ln(aA/A) r=0.71 The Han rivers f=-0.0035+01267 on qA r=0.75 f=1.1311+0.1263 ln(qA/A) r=0.71 L=302.9064-43.8490 ln qA r=0.84 The Geun rivers(Mu-sin Cheon) f=0.295+0.1823 ln qA r=0.93 f=0.8417+0.1823 ln(qA/A) r=0.93 L=40.0456+62.0346 ln qA r=0.94 The Yeong-san rivers f=0.3766+0.0598 ln qA r=0.79 f=0.8084+0.0599 ln(qA/A) r=0.79 The Seom-jin rivers f=-1.3875+0.6505 ln qA r=0.92 f=2.1633+0.3465 ln(qA/A) r=0.76 Small river basin in Pusan f=0.3635+0.1120 ln qA r=0.87

鐵筋콘크리드 플래트 슬래브의 最適設計에 관한 硏究

朴文浩,嚴采永,柳又秀 동아대학교 공과대학 부설 한국자원개발연구소 1980 硏究報告 Vol.4 No.2

The study is to carry out Optimum cross-section of singly reinforced Concrete flat Slabs, without drop panels and with drop panels, based on both the theory of working stressed design and the theory of ultimate stressed design for the minimum cost design. Cost objective function for minimizing the construction cost is obtained by considering the cost of steel, concrete and forming. And the design constraints used are the flexural moment, the under-reinforced steel ratio, minimum depth, minimum area of steel, shearing force. Since some of design constraints are constituted nonlinear programming problems, they are transformed into the set of successive linear programming problems, using the Taylor series expansion, and the numerical example solved by using computer. By the numerical example, the optimum cross-section of reinforced concrete flat slabs, the optimum depth, economics between WSD and USD, conventional design and optimum design is studied.