• Advances in Computational Design
• /
• 제1권3호
• /
• pp.253-264
• /
• 2016

Based on the variation of strain along the cross section, any region in a structural member can be classified into two regions namely, Bernoulli's region (B-region) and Disturbed region (D-region). Since the variation of strain along the cross section for a B-region is linear, well-developed theories are available for their analysis and design. On the other hand, the design of D-region is carried out based on thumb rules and past experience due to the presence of nonlinear strain distribution. Strut-and-Tie method is a novel approach that can be used for the analysis and design of both B-region as well as D-region with equal importance. The strut efficiency factor (${\beta}_s$) is needed for the design and analysis of concrete members using Strut and Tie method. In this paper, equations for finding ${\beta}_s$ for bottle shaped struts in concrete deep beams (a D-region) with and without steel fibres are developed. The effects of transverse reinforcement on ${\beta}_s$ are also considered. Numerical studies using commercially available finite element software along with limited amount of experimental studies were used to find ${\beta}_s$.

• Structural Engineering and Mechanics
• /
• 제54권6호
• /
• pp.1097-1109
• /
• 2015

A novel optimization approach for reinforced concrete (RC) biaxially loaded columns is proposed. Since there are several design constraints and influences, a new computation methodology using iterative analyses for several stages is proposed. In the proposed methodology random iterations are combined with music inspired metaheuristic algorithm called harmony search by modifying the classical rules of the employed algorithm for the problem. Differently from previous approaches, a detailed and practical optimum reinforcement design is done in addition to optimization of dimensions. The main objective of the optimization is the total material cost and the optimization is important for RC members since steel and concrete are very different materials in cost and properties. The methodology was applied for 12 cases of flexural moment combinations. Also, the optimum results are found by using 3 different axial forces for all cases. According to the results, the proposed method is effective to find a detailed optimum result with different number of bars and various sizes which can be only found by 2000 trial of an engineer. Thus, the cost economy is provided by using optimum bars with different sizes.

• Journal of Information Processing Systems
• /
• 제8권4호
• /
• pp.653-668
• /
• 2012

In this study, an improved HMM based recognition model is proposed for online English and Korean handwritten characters. The pattern elements of the handwriting model are sub character strokes and ligatures. To deal with the problem of handwriting style variations, a modified Hierarchical Clustering approach is introduced to partition different writing styles into several classes. For each of the English letters and each primitive grapheme in Korean characters, one HMM that models the temporal and spatial variability of the handwriting is constructed based on each class. Then the HMMs of Korean graphemes are concatenated to form the Korean character models. The recognition of handwritten characters is implemented by a modified level building algorithm, which incorporates the Korean character combination rules within the efficient network search procedure. Due to the limitation of the HMM based method, a post-processing procedure that takes the global and structural features into account is proposed. Experiments showed that the proposed recognition system achieved a high writer independent recognition rate on unconstrained samples of both English and Korean characters. The comparison with other schemes of HMM-based recognition was also performed to evaluate the system.

• Structural Engineering and Mechanics
• /
• 제34권1호
• /
• pp.15-38
• /
• 2010

In order to predict the shear strengths of reinforced concrete beams, many deterministic models have been developed based on rules of mechanics and on experimental test results. While the constant and variable angle truss models are known to provide reliable bases and to give reasonable predictions for the shear strengths of members with shear reinforcement, in the case of members without shear reinforcement, even advanced models with complicated procedures may show lack of accuracy or lead to fairly different predictions from other similar models. For this reason, many research efforts have been made for more accurate predictions, which resulted in important recent publications. This paper develops probabilistic shear strength models for reinforced concrete beams without shear reinforcement based on deterministic shear strength models, understanding of shear transfer mechanisms and influential parameters, and experimental test results reported in the literature. Using a Bayesian parameter estimation method, the biases of base deterministic models are identified as algebraic functions of input parameters and the errors of the developed models remaining after the bias-correction are quantified in a stochastic manner. The proposed probabilistic models predict the shear strengths with improved accuracy and help incorporate the model uncertainties into vulnerability estimations and risk-quantified designs.

• Advances in concrete construction
• /
• 제1권1호
• /
• pp.103-119
• /
• 2013

The applicability of limit analysis methods in design and assessment of concrete structures generally requires a certain plastic deformation capacity. The latter is primarily provided by the ductility of the reinforcement, being additionally affected by the bond properties between reinforcing steel and concrete since they provoke strain localization in the reinforcement at cracks. The bond strength of reinforcing bars is not only governed by concrete quality, but also by construction details such as bar ribbing, bar spacing or concrete cover thickness. For new concrete structures, a potentially unfavorable impact on bond strength can easily be anticipated through appropriate code rules on construction details. In existing structures, these requirements may not be necessarily satisfied, consequently requiring additional considerations. This two-part paper investigates in a theoretical study the impacts of the most frequently encountered construction details which may not satisfy design code requirements on bond strength, steel strain localization and plastic deformation capacity of cracked structural concrete. The first part introduces basic considerations on bond, strain localization and plastic deformation capacity as well as the fundamentals of the Tension Chord Model underlying the further investigations. It also analyzes the impacts of the hardening behavior of reinforcing steel and concrete quality. The second part discusses the impacts of construction details (bar ribbing, bar spacing, and concrete cover thickness) and of additional structure-specific features such as bar diameter and crack spacing.

• 대한조선학회논문집
• /
• 제40권3호
• /
• pp.29-36
• /
• 2003

In rough seas, bow-flare regions of the fine ships (container ship and PCC) are subject to high impact pressures due to the bow-flare slamming. And many ships suffer structural damages in that region, even though they were built under the bow structure strengthening rules of the ship classes. So, a new design method for bow-flare structure is highly required. In this paper, a new prediction method of the bow-flare impact pressure (in terms of equivalent static pressure) acting on the fine ships' bow is presented. This method is based on the 11 fine ships' damage analysis and the mechanisms of water entry impact and breaking wave impact. Calculation results of the bow-flare impact pressure and the shell plate thickness are shown and discussed. Through the example calculations, it was found that the present method is useful for the structure design of the fine ships' bow.

• 대한조선학회논문집
• /
• 제40권3호
• /
• pp.22-28
• /
• 2003

In rough seas, bow-flare regions of the full ships (tanker and bulk carrier) are subiect to high impact pressures due to the on-coming breaking waves. And many ships suffer structural damages in that region, even though they were built under the bow structure strengthening rules of the ship classes. So, a new design method for bow-flare structure is highly required. In this paper, a new prediction method of the bow-flare impact pressure (in terms of equivalent static pressure) acting on the full ships' bow is presented. This method is based on the 6 full ships' damage analysis and the breaking wave impact mechanism. Calculation results of the bow-flare impact pressure and the shell plate thickness are shown and discussed. Through the example calculations, it was found that the present method is useful for the structure design of the full ships' bow.

• 한국컴퓨터정보학회논문지
• /
• 제19권11호
• /
• pp.105-113
• /
• 2014

본 논문에서는 법령 온톨로지 구축을 위해 법령의 구조적 특징과 요소 간의 관계에 대해 분석 정리하고 정리된 내용을 바탕으로 OWL DL 수준의 매핑 규칙을 제안한다. 제안하는 매핑 규칙은 국내 법령 관계의 상-하위 구조, 법령의 고유 속성, 법률 간의 참조 관계와 같은 구조적인 관계의 TBox를 구축하는 방법과 법률 문장을 분석하여 조문 규정 별로 나타나는 문장의 패턴 유형을 선별, ABox로 구축될 수 있는 요소를 표현한다. 제안된 매핑 규칙은 일반 텍스트로 설명되고 있는 국내의 법령을 컴퓨터가 이해 가능한 수준의 정보로 변환 되어 법령 지식 베이스로 활용 가능하다.

• International Journal of Computer Science & Network Security
• /
• 제21권12spc호
• /
• pp.544-548
• /
• 2021

Scientific and technical development, as well as the emergence of new types of contracts, which do not have their expression in current legislation, force us to explore the issues of contract law to adapt to change. In this context, the principle of freedom of contract is fundamental, which states that each person has the right to enter into a contractual relationship at his discretion. However, such freedom is not absolute, because the freedom of one person should not violate the freedom of another. Together with the conflict of private and public interests, these phenomena are a field for the study of topical issues of theory and application of the principle of freedom of contract in practice. Research methods are philosophical, general scientific, and special scientific methods, in particular, system-structural, formal-legal, hermeneutic; methods of analysis, synthesis, etc. As a result of the research, the main characteristics of the principle of freedom of contract, its role for private law regulation of contract law are given; approaches to understanding the restriction of contract freedom are analyzed; typical examples and means of such restrictions are identified; demonstrated how contract freedom is embodied in the use of IT tools, which types of contracts are most common in the digital environment.

• Structural Engineering and Mechanics
• /
• 제71권3호
• /
• pp.233-244
• /
• 2019

Steel jacketing technique is a retrofitting method often employed for static and seismic strengthening of existing reinforced concrete columns. When no continuity is given to angle chords as they cross the floor, the jacket is considered "indirectly loaded", which means that the load acting on the column is transferred partially to the external jacket through interface shear stresses. The evaluation of load transfer mechanism between core and jacket is not straightforward to be modeled, due to the absence of knowledge of a proper constitutive law of the concrete-to-steel interface and to the difficulties in taking into account the mechanical nonlinearities of materials. This paper presents an incremental analytical/numerical approach for evaluating the compressive response of RC columns strengthened with indirectly loaded jackets. The approach allows calculating shear stresses at the interface between core and jacket and predicting the axial capacity of retrofitted columns. A proper constitutive law is proposed for modelling the interaction between the steel and the concrete. Based on plasticity rules and the non-linear behaviour of materials, the column is divided into portions. After a detailed parametric analysis, comparisons are finally made by theoretical predictions and experimental results available in the literature, showing a good agreement.