http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A Computational Model for Prestressed Concrete Hollow-Core Slab Under Natural Fire
R. Pe?enko,T. Hozjan,I. Planinc,S. Bratina 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.1
Performance-based approach, introducing a new two-phase computational model for determining the response of prestressed hollow-core concrete slab exposed to natural fire including heating and cooling phase, is presented. Firstly, the two-dimensional coupled hygro-thermo-chemical model is used to determine time dependent temperature and moisture field in the characteristic cross-section of the concrete hollow-core slab during fire. In addition, the influence of opening on the temperature distribution over prestressed hollow-core concrete slab is accounted for. Secondly, stress–strain state of prestressed concrete hollow-core slab is determined with a newly developed one-dimensional geometrical and material non-linear model, which includes a slip between concrete and tendon. Temperature dependent mechanical properties of concrete, tendon and bond stiffness are accounted for in the model. Model validation showed that the presented two-phase computational model is suitable for the analysis of prestressed hollow-core concrete slab exposed to natural fire. Furthermore, parametric studies revealed that heat exchange between the concrete section and the opening has a significant influence on the development of temperatures in the slab, particularly in the cooling phase, and consequently also on the development of slab displacements. In addition, it was identified that accounting for the slip between concrete and tendon enables the determination of the bond stress distribution and evaluation of the load bearing capacity of the contact.
부윤섭,배규웅,신상민 한국공간구조학회 2023 한국공간구조학회지 Vol.23 No.2
A two-hour fire-resistance PC hollow slab for residential use was developed to secure structural and fire-resistance performance and to be applied to the general building and apartment housing markets. Compared to the existing hollow slab, in order to secure the same or better structural performance and economic feasibility by reducing the quantity, it was attempted to secure the fire resistance performance by reducing the concrete filling rate in the cross section and adjusting the thickness of the upper and lower flanges by optimizing the hollow shape in the cross section of the slab. For structural performance evaluation, experiments were performed on PC hollow slabs by varying the member thickness and the presence or absence of overlaid concrete, and all of the experimental results showed that the design strength was sufficiently exhibited and that stability during construction was possible. The developed synthetic PC hollow slab has secured fire resistance and residential performance so that it can be applied to all buildings, and it is intended to be immediately applied to the field.
전단철근이 배치된 프리캐스트 프리스트레스트 중공슬래브의 구조성능 평가
김상윤,김선훈,이득행,한선진,김길희 한국구조물진단유지관리공학회 2023 한국구조물진단유지관리공학회 논문집 Vol.27 No.1
This study aims to investigate the structural performance of hollow-core slab (HCS) memebers with 400 ㎜ thickness. To this end, a totalof four HCS specimens were fabricated based on the individual mold method to provide shear reinforcement, unlike the extrusion method. The keyvariables were chosen as the presence of topping concrete, core-filling concrete, and shear reinforcements. The crack patterns and load-displacementresponses of the test specimens were analyzed in detail. Test results showed that inclined shear cracking occurred all the specimens, and that the specimenwith shear reinforcement on the web of HCS unit had higher strength and ductility than the specimen without shear reinforcement. In particular, shearreinforcements placed on the web of HCS unit effectively resisted not only to vertical shear force but also to horizontal shear force between the interfaceof HCS unit and topping concrete. In addition, it was discovered that the method in which shear reinforcements are placed on the web of HCS unitis more effective in improving structural performance than core-filling method 이 연구에서는 높이가 400 ㎜인 중공슬래브(Hollow-Core Slab, 이하 HCS)의 구조성능을 평가하기 위한 실대형 실험을 수행하였으며, 기존의 압출성형방식이 아닌 단일몰드방식을 적용하여 총 4개의 HCS를 제작하였다. 실험의 주요 변수는 토핑콘크리트의 유무, 전단보강근의 배치 유무 및 위치로 설정하였으며, 실험체들의 균열패턴 및 하중-변위 응답을 상세히 분석하였다. 실험결과 전단철근이 배치된 HCS 실험체들은 휨강도를 달성하였고, 이후에 최종적인 파괴는 사인장균열에 의하여 지배되었으며, HCS 유닛 웨브 내에 전단철근이 배치되지 않은실험체들의 경우 설계기준을 통해 산정된 공칭휨강도를 발현하지 못하였다. 전단철근을 HCS 유닛에 배근 할 경우에는 전단강도가 약 8~23%증가하는 것으로 나타났으며, HCS의 중공을 철근콘크리트로 보강하는 방법보다 전단성능 향상에 더 효과적인 것으로 나타났다.
E. Michelini,P. Bernardi,R. Cerioni,B. Belletti 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.4
The paper presents the results of flexural and shear tests up to failure on full-scale hollow-core slabs (HCS) having a depth of 500 mm. A detailed non-linear 2D finite element model is also developed to predict the stress distribution and crack pattern within the slabs, providing a well match with experimental results. Experimental and numerical results are compared with analytical calculations provided by Product Standard EN 1168, highlighting the inaccuracy of technical regulations in predicting shear behavior. The proposed numerical procedure is instead viable and sound for the design and the strength assessment of HCS, and can be extended easily to the analysis of whole floor systems.
Genetic algorithm optimization of precast hollow core slabs
Luca Sgambi,Konstantinos Gkoumas,Franco Bontempi 사단법인 한국계산역학회 2014 Computers and Concrete, An International Journal Vol.13 No.3
Precast hollow core slabs (HCS) are technically advanced products in the precast concrete industry, widely used in the last years due to their versatility, their multipurpose potential and their low cost. Using three dimensional FEM (Finite Element Method) elements, this study focuses on the stresses induced by the prestressing of steel. In particular the investigation of the spalling crack formation that takes place during prestressing is carried out, since it is important to assure the appropriate necessary margins concerning such stresses. In fact, spalling cracks may spread rapidly towards the web, leading to the detachment of the lower part of the slab. A parametric study takes place, capable of evaluating the influence of the tendon position and of the web width on the spalling stress. Consequently, after an extensive literature review on the topic of soft computing, an optimization of the HCS is performed by means of Genetic Algorithms coupled with 3-D FEM models.
김두산 ( Kim Doo-san ),강성원 ( Gang Seong-won ),최경은 ( Choi Kyeong-eun ),이용준 ( Lee Yong-jun ),김길희 ( Kim Kil-hee ) 한국구조물진단유지관리공학회 2019 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.23 No.2
이 연구는 압출성형으로 생산되고 있는 프리스트레스트 콘크리트 중공 슬래브(HCS)의 휨 성능을 평가하고자 단면의 높이를 변수로 휨 실험을 수행하였다. HCS는 단면의 높이에 따라 총 2체를 제작하였으며, 1,000kN의 액추에이터를 이용하여 4점 가력을 실시하였다. 실험결과, HCS의 휨강도는 예측결과에 대한 실험결과의 비가 평균 1.01 ∼ 1.04를 나타내어 현행 설계기준에서 요구되는 구조성능을 만족하는 것으로 나타났다.