Behavior of FRP-reinforced steel plate shear walls with various reinforcement designs

Mehdi Seddighi,Mohammad A. Barkhordari,S.A.A. Hosseinzadeh 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.5

The nonlinear behavior of single- and multi-story steel plate shear walls (SPSWs) strengthened with three different patterns of fiber reinforced polymer (FRP) laminates (including single-strip, multi-strip and fully FRP-strengthened models) is studied using the finite element analysis. In the research, the effects of orientation, width, thickness and type (glass or carbon) of FRP sheets as well as the system aspect ratio and height are investigated. Results show that, despite an increase in the system strength using FRP sheets, ductility of reinforced SPSWs is decreased due to the delay in the initiation of yielding in the infill wall, while their initial stiffness does not change significantly. The content/type/reinforcement pattern of FRPs does affect the nonlinear behavior characteristics and also the mode and pattern of failure. In the case of multi-strip and fully FRP-strengthened models, the use of FPR sheets almost along the direction of the infill wall tension fields can maximize the effectiveness of reinforcement. In the case of single-strip pattern, the effectiveness of reinforcement is decreased for larger aspect ratios. Moreover, a relatively simplified and approximate theoretical procedure for estimating the strength of SPSWs reinforced with different patterns of FRP laminates is presented and compared with the analytical results.

QR code as speckle pattern for reinforced concrete beams using digital image correlation

Krishna, B. Murali,Tezeswi, T.P.,Kumar, P. Rathish,Gopikrishna, K.,Sivakumar, M.V.N.,Shashi, M. Techno-Press 2019 Structural monitoring and maintenance Vol.6 No.1

Digital Image Correlation technique (DIC) is a non-contact optical method for rapid structural health monitoring of critical infrastructure. An innovative approach to DIC is presented using QR (Quick Response) code based random speckle pattern. Reinforced Cement Concrete (RCC) beams of size $1800mm{\times}150mm{\times}200mm$ are tested in flexure. DIC is used to extract Moment (M) - Curvature (${\kappa}$) relationships using random speckle patterns and QR code based random speckle patterns. The QR code based random speckle pattern is evaluated for 2D DIC measurements and the QR code speckle pattern performs satisfactorily in comparison with random speckle pattern when considered in the context of serving a dual purpose. Characteristics of QR code based random speckle pattern are quantified and its applicability to DIC is explored. The ultimate moment-curvature values computed from the QR code based random speckled pattern are found to be in good agreement with conventional measurements. QR code encrypts the structural information which enables integration with building information modelling (BIM).

Effects of Incorporating Steel and Glass Fibers on Shear Behavior of Concrete Column-Beam Joints

Liaqat Ali Qureshi,Usman Muhammad 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.8

This paper presents the effects of adding steel and glass fibers on structural behavior of concrete column-beam joints in comparisonwith the conventional concrete. Nine full-scaled exterior column-beam joints cast by one traditional concrete (declared as controlcolumn-beam joint), four steel fiber reinforced & four glass fiber reinforced concretes were tested under monotonic loading. Percentage of each fiber added in respective column-beam joint was varied from 0 to 2% with an increment of 0.5%. Steel fiberswere added on weighted basis of concrete while glass fibers were added on the weighted percentage of cement. Results wereevaluated with respect to first crack load, ultimate load, deflections and crack patterns. Finite element modeling was carried out onANSYS version 11 by using material properties evaluated by physical testing of concrete used in the casting of joints. Resultsobtained from FEM and experimental program were found to be in good agreement with each other. It was also found that theincorporation of fibers in column-beam joints improved their stiffness, ductility, strength and it could be one of the likely alternateapproaches for reducing the overcrowding of lateral reinforcement in column-beam joints.

트래픽 패턴 학습 기반의 다중 교차로 교통신호 제어

최진섭(Jinseop Choi),조영태(Youngtae Jo),정인범(Inbum Jung) 한국정보과학회 2014 정보과학회 컴퓨팅의 실제 논문지 Vol.20 No.3

교차로의 신호제어는 지금까지 설치 및 사용 간단하다는 이유로 고정식 제어 방식을 사용해왔다. 고정식 제어는 교차로의 교통량을 실시간으로 반영하지 못하기 때문에 효율성이 떨어진다. 이러한 문제를 해결하기 위해 감응식 제어가 사용되고 있지만 단일 교차로의 교통량만을 이용하기 때문에 복잡한 도심지 교통 환경에 적용하기에는 한계가 있다. 하지만 도심지의 교통은 매일 반복적인 패턴을 보인다는 특징이 있다. 본 논문에서는 반복적인 교통 패턴을 학습하여 도심지 교통망을 효율적으로 제어할 수 있는 강화학습이론 기반의 새로운 신호제어 알고리즘을 제안한다. 제안하는 알고리즘은 교통패턴 학습, 경로탐색, 교통 혼잡구간 탐색, 다중 교차로 제어의 4가지 단계로 이루어지며, 이들의 연동은 교통 혼잡을 빠르게 해소할 수 있게 한다. 특히, 시간이 지날수록 학습결과누적으로 해당 교통 환경에 최적화된 신호제어가 가능하다. 제안하는 알고리즘의 평가를 위하여 마이크로스코픽 시뮬레이터를 사용하여 기존의 신호제어 기법과 성능을 비교한다. A pre-timed signal control has been used due to the simplicity of installation and implementation. Since the pre-timed signal control does not reflect real-time traffic information, the efficiency of intersection control is limited. To address the inefficiency of pre-timed signal control, actuated signal control is introduced. However, the actuated signal control has limited applicability in urban environment with complex traffic flow because only a single intersection is considered. However, urban traffic flow has a characteristic of repetitive flow pattern. In this paper, a new traffic signal control based on reinforcement learning is proposed for the effective multiple intersections control of urban traffic environment. The proposed method is composed of traffic pattern learning, path searching, congested area searching, and multiple signals controlling. The interlocking of these components alleviate the traffic congestion problem as soon as possible. In particular, as the learning of traffic pattern is accumulated, the optimal signal control in various traffic conditions can be produced. To prove the efficiency of the proposed signal control method, other previous signal control methods are compared on microscopic simulator.

Experimental Study of the Behavior of Circular Column-Foundation Connections according to the Internal Reinforcement of the Column

Hee-Ju Kim,Junsu Ham,Ki-Tae Park 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

Economical design of the column-foundation connections is difficult to achieve due to the complex structural details of the anchor frame in the foundation concrete following the arrangement of 2 or 3 lines of connections using anchors that are needed to deal with the enlargement of the constructions. This study identified the problems of the conventional circular CFT columnfoundation connections and proposed structural details to solve them. As a solution, high-tension bolts were adopted instead of the common anchors to provide new structural details enabling the anchor frame supporting the anchored connection to be omitted. Based on these new structural details, the specimens were manufactured with different types of internal reinforcements. The corresponding failure patterns, deformation capacities, and energy absorption hysteresis were compared and the behavior was analyzed to propose a rational shape of the connection details.

강섬유보강 철근콘크리트 보의 휨성능 평가

하기주 ( Ha Gee-joo ),신종학 ( Shin Jong-hack ),주정준 ( Ju Jung-jun ) 한국구조물진단유지관리공학회 2000 한국구조물진단유지관리공학회 논문집 Vol.4 No.1

In this experimental program specimens, designed by the test variables, such as percentage of steel fiber incorporated, were constructed and tested to evaluate the flexural performance of reinforced steel fiber concrete beams. Based on the test results reported in this study, the following conclusions are made. Comparing with the load-displacement relationship of standard specimen, specimen over 0.5% of steel fiber incorporated, could be improved significantly flexural performance, such as capacity, ductility, and crack pattern. As increasing in quantity of steel fiber incorporated(0.5%~2.0%), the flexural strength of each specimen was shown the enhancement of 13%~40% in comparision with the standard specimen BSS.

Quasi-static cyclic displacement pattern for seismic evaluation of reinforced concrete columns

E. Yüksel,M. Sürmeli 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.3

Although earthquakes generate random cyclic lateral loading on structures, a quasi-static cyclic loading pattern with gradually increasing amplitude has been commonly used in the laboratory tests because of its relatively low cost and simplicity compared with pseudo-dynamic and shake table tests. The number, amplitudes and sequence of cycles must be chosen appropriately as important parameters of a quasi-static cyclic loading pattern in order to account for cumulative damage matter. This paper aims to reach a new cyclic displacement pattern to be used in quasi-static tests of well-confined, flexure-dominated reinforced concrete (RC) columns. The main parameters of the study are sectional dimensions, percentage of longitudinal reinforcement, axial force intensity and earthquake types, namely, far-fault and near-fault.

Quasi-static cyclic displacement pattern for seismic evaluation of reinforced concrete columns

Yuksel, E.,Surmeli, M. Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.3

Although earthquakes generate random cyclic lateral loading on structures, a quasi-static cyclic loading pattern with gradually increasing amplitude has been commonly used in the laboratory tests because of its relatively low cost and simplicity compared with pseudo-dynamic and shake table tests. The number, amplitudes and sequence of cycles must be chosen appropriately as important parameters of a quasi-static cyclic loading pattern in order to account for cumulative damage matter. This paper aims to reach a new cyclic displacement pattern to be used in quasi-static tests of well-confined, flexure-dominated reinforced concrete (RC) columns. The main parameters of the study are sectional dimensions, percentage of longitudinal reinforcement, axial force intensity and earthquake types, namely, far-fault and near-fault.

Determination of the influence of infill pattern and fiberglass reinforcement on the tensile properties of additively manufactured material by FDM technology

Marko Delić,Vesna Mandić,Srbislav Aleksandrović,Dušan Arsić 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

FDM technology is among the most widely used additive manufacturing technologies. The most popular materials are ABS and PLA, but lately nylon has been used more often. The aim of the paper is to determine the impact of infill pattern and continuous fiberglass reinforcement on the tensile properties of additively manufactured composite material. The samples were made of Onyx as matrix material on a Markforged Onyx Pro printer, with and without varying fiberglass volume fraction. In addition, five different infill patterns (solid, triangular, rectangular, hexagonal and gyroid) were investigated. The experimental results revealed that infill patterns have different effects on the tensile strength and elastic behavior of the material, but the consumption of material and time should also be considered. The use of continuous fiberglass reinforcement significantly improves the tensile characteristics of the material. Proper arrangement of fibers in multiple layers can give better tensile properties of the material.

치매 환자의 보행 향상을 위한 강화학습 알고리즘 적용방안에 관한 연구

김진수 한국지식정보기술학회 2022 한국지식정보기술학회 논문지 Vol.17 No.1

This study was conducted to effectively solve the abnormal walking problem caused by the increase in dementia patients, which is a representative problem in an aging society. Walking in dementia patients occurs in abnormal walking patterns and can cause fatal diseases in various human structures, including the brain. Therefore, detailed gait analysis is required for dementia patients, and measures are needed to identify the cause of the problem and solve the problem. Therefore, in this study, a method of applying a reinforcement learning algorithm within the existing walking analysis system was studied as a method to improve the walking condition of dementia patients. The reinforcement learning algorithm calculates the range of joints and the amount of change in walking variables by walking state for the state and behavior that occur while the patient is walking through the gap between the normal range of joints. Accordingly, the system may automatically perform gait motion feedback of the patient. This feedback is expected to be able to learn normal walking patterns and optimize walking. Future research plans to find ways to collect big data related to walking from dementia patients with various symptoms and use it for customized gait treatment for each patient.