• 한국지반공학회논문집
• /
• 제35권11호
• /
• pp.75-95
• /
• 2019

본 연구에서는 사질토층을 지나 풍화암에 소켓된 매입 PHC말뚝에 대한 수치해석 결과를 분석하여 정리한 도표 또는 도해로부터 매입 PHC말뚝의 동원지지력을 구하는 방법을 제안하였다. 즉, 수치해석 결과인 하중-침하량 곡선에서 5% 직경에 해당하는 침하량에서 발현된 사질토층의 동원주면마찰력, 풍화암층의 동원주면마찰력과 동원선단지지력을 산정할 수 있는 표해 또는 도해를 제안하였다. 이때 허용압축지지력은 동원 지지력에 안전율 3.0을 적용하여 산정하였다. 사질토층을 지나 풍화암에 소켓된 매입 PHC말뚝의 허용압축지지력은 사질토층의 허용주면마찰력과 풍화암층의 허용주면마찰력 및 허용선단지지력을 합산하여 산정하는 것으로 제안하였고, 각 허용압축지지력 성분을 구할 수 있는 절차도 제시되어 있다. 본 연구에서 제안된 동원지지력 산정용 표해(또는 도해)를 사용할 경우, 적정 설계에서 PHC말뚝의 설계효율(D_E)은 85%로 나타났으며, 따라서 최적 설계에서는 PHC말뚝의 장기허용압축하중(P_all) 까지도 활용할 수 있는 것으로 나타났다. 그리고 PHC말뚝의 우수한 압축하중 지지 성능을 효과적으로 활용하기 위하여 지반의 허용압축지지력(Q_all)이 말뚝의 허용압축하중(P_all) 이상이 될 수 있도록 설계할 것을 권장하였다.

• 한국가구학회지
• /
• 제18권4호
• /
• pp.287-295
• /
• 2007

To obtain a design data for box beams used as headers in light-frame timber construction, $2{\times}6\;(38{\times}140mm),\;2{\times}8\;(38{\times}184mm),\;2{\times}10\;(38{\times}235mm)\;and\;2{\times}12\;(38{\times}286mm)$ members were built as box beam specimens for bending tests. The allowable bending stresses for box beams were obtained through bending tests of these specimens, and span tables were calculated for various loading conditions based on the allowable bending stresses obtained. The allowable bending stresses were determined as the bending stresses at 10mm deflection of specimens from the results of bending tests of box beam specimens. Span tables for box beams were obtained assuming five loading conditions for headers used in exterior walls and two loading conditions for headers used in interior walls. Among these 7 loading conditions, 5 loading conditions applied to headers in exterior walls included the dead loads, the live loads and the snow loads and 2 loading conditions applied to headers in interior walls included the dead loads and the live loads.

• 농업과학연구
• /
• 제38권3호
• /
• pp.533-540
• /
• 2011

This study is to develop a mulit-layer glued columns for construction of Korean-style houses by using domestic small diameter logs. Dried small square lumber glued each other to develop a multi-layer glued columns and evaluated its performance of strength. Then, predicted the design load of multi-layer glued columns and make a comparison between actual load and design load of multi-layer glued columns. In the results, allowable load by allowable stress of multi-layer glued columns was measured one-third of actual columns load and prediction load was measured less than 10~30% of the actual load. Therefore, muilt-layer glued member has a standard allowable stress of compressive of 13 MPa (Larix leptolepis) and 19 MPa (Chamaecyparis obtusa) when used as columns. Also, using compression strength of small diameter square logs could calculate maximum loads of multi-layer glued member as column.

• Management Science and Financial Engineering
• /
• 제19권2호
• /
• pp.19-29
• /
• 2013

Refuse collection network design, one of major decision problems in reverse logistics, is the problem of locating collection points and allocating refuses at demand points to the opened collection points. As an extension of the previous models, we consider capacity and maximum allowable distance constraints at each collection point. In particular, the maximum allowable distance constraint is additionally considered to avoid the impractical solutions in which collection points are located too closely. Also, the additional distance constraint represents the physical distance limit between collection and demand points. The objective is to minimize the sum of fixed costs to open collection points and variable costs to transport refuses from demand to collection points. After formulating the problem as an integer programming model, we suggest an optimal branch and bound algorithm that generates all feasible solutions by a simultaneous location and allocation method and curtails the dominated ones using the lower bounds developed using the relaxation technique. Also, due to the limited applications of the optimal algorithm, we suggest two heuristics. To test the performances of the algorithms, computational experiments were done on a number of test instances, and the results are reported.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
• /
• pp.183-190
• /
• 1998

In this study, I-type girders, main members of a steel composite bridge, are designed by Load and Resistance Factor Design method as well as Allowable Stress Design method. The width, height web thickness and flange thickness of main girders are set as design variables. The design program connects optimization program ADS, which is coded with FORTRAN, and a main program coded with $C^{++}$. In this study, it is shown that in this particular steel composite bridge, the design by The Load and Resistance Factor Design method is more economical than that by The Allowable Stress Design method.d.

• 한국가스학회지
• /
• 제18권6호
• /
• pp.14-20
• /
• 2014

본 연구에서 배관계의 구조 건전성을 보장할 수 있는 배관 지지대 설계 절차를 ASME 코드에 따라 수행하였다. 본 설계 절차는 단순화된 설계식 및 여러 하중에 대한 보수적인 허용 값을 제공한다. 배관 스트랩 지지대를 구성하는 바닥판, 바닥 지지판 및 앵커 볼트에 대한 응력해석을 수행하여 ASME 코드 상호작용 설계식을 사용하여 구조 건전성을 평가하였다. 여러 하중에 대한 하중 및 하중 조합에 대한 응력 수준이 허용 값 이내에 분포하므로 구조적 건전성을 유지한다고 평가할 수 있다.

• Nuclear Engineering and Technology
• /
• 제23권4호
• /
• pp.363-373
• /
• 1991

핵연료봉 내압 설계기준에 의하면 핵연료봉 갭의 증가만 발생하지 않는다면 봉내압이 계통압력을 초과할 수 있다. 본 연구에서는 이러한 봉내압 설계기준에 따른 정량적이고 보수적인 허용 봉내압을 봉출력의 함수로 생산하였는 바 허용 봉내압은 봉출력의 증가에 따라 감소하였다. 한편, 본 연구에서 구한 허용 봉내압을 봉내압 설계 기준으로 적용하면 핵연료봉 압력 검증을 위한 현행 설계절차를 단순화시킨다. 왜냐하면, 봉내압이 계통압력을 초과할 경우 각각의 주어진 시간 및 축 방향 지점에서 핵연료봉 갭 증가를 계산해야 하는 현행 설계절차가 불필요하기 때문이다.

• Structural Engineering and Mechanics
• /
• 제82권6호
• /
• pp.757-770
• /
• 2022

For the design of flexural and shear crack control for reinforced concrete (RC) beams related to serviceability and reparability ensuring, eight simply-supported normal-strength reinforced concrete (NSRC) beam specimens are tested and the existing high-strength reinforced concrete (HSRC) experimental data are included in the investigation of this work. According to the investigation results of flexural and shear cracks, this works modifies the existing design formulas to determine the spacing of the tensile reinforcement for the flexural crack control of a HSRC/NSRC beam design. Additionally, for a specified shear crack width of 0.4 mm, the allowable stresses of the shear reinforcement are also identified. For the serviceability and reparability ensuring of HSRC/NSRC beams, this works proposes the relationship curves between the maximum flexural width and allowable stress of the tensile reinforcement, and the relationship curves between the shear crack width and allowable shear force that can be used to do the crack width control directly.

• Structural Engineering and Mechanics
• /
• 제27권5호
• /
• pp.575-588
• /
• 2007

In this paper, two algorithms are presented for the optimum design of geometrically nonlinear steel space frames using tabu search. The first algorithm utilizes the features of short-term memory (tabu list) facility and aspiration criteria and the other has long-term memory (back-tracking) facility in addition to the aforementioned features. The design algorithms obtain minimum weight frames by selecting suitable sections from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange (W) shapes. Stress constraints of AISC Allowable stress design (ASD) specification, maximum drift (lateral displacement) and interstorey drift constraints were imposed on the frames. The algorithms were applied to the optimum design of three space frame structures. The designs obtained using the two algorithms were compared to each other. The comparisons showed that the second algorithm resulted in lighter frames.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집A
• /
• pp.357-362
• /
• 2000

Allowable stress design(ASD) method has been widely used to design steel structures such as boiler and heat recovery steam generator(HRSG) of power plant. However, many researchers are recently intrested in road and resistance factor design(LRFD) method which may take the place of ASD. In this work, the weight calculation of steel structure was compared when ASD and LRFD were applied respectively. For the calculation of weight of steel structure, computer program was developed and applied to obtain beam weight. Using this program and GTSTRUDL, structural design program, weight of steel structure is calculated. As a result of weight calculation, maximum 5.4% of weight reduction is achieved among examples of this study by applying LRFD comparing with the result of ASD, and those results quite dependent on the applied load and member classification.