An Innovative FRP Confining System for Repairing Rectangular Columns

2001 ◽  
Author(s):  
Ibrahim Mahfouz ◽  
Tarek Rizk ◽  
Shahram Sarkani
Keyword(s):  
Rectangular Columns

BEHAVIOR OF RC BUILDING COLUMNS UNDER CYCLIC LOADING: EXPERIMENTAL STUDY

2012 ◽  
Vol 06 (04) ◽  
pp. 1250026 ◽  
Author(s):  
HUGO RODRIGUES ◽  
ANTONIO ARÊDE ◽  
HUMBERTO VARUM ◽  
ANIBAL COSTA
Keyword(s):  
Damage Index ◽  
Physical Damage ◽  
Uniaxial Test ◽  
Experimental Campaign ◽  
Simplified Method ◽  
Rc Building ◽  
Global Deformation ◽  
Result Analysis ◽  
Rectangular Columns ◽  
Test Result

An experimental campaign is underway in order to understand the behavior of rectangular columns under uniaxial and biaxial flexure. The present paper addresses the initial part of that campaign, by reporting on two columns tested under uniaxial bending in one horizontal direction and then submitted to another uniaxial test in the other direction. The test result analysis focuses on the contributions of flexure, shear and slip components to the global deformation. The experimental results were compared with a simplified method for column response. The Park and Ang damage index is calculated and compared with the physical damage observed.

Punching shear behaviour of flat slabs with different reinforcement schemes: openings and rectangularity effects

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Donia Salman ◽  
Rabab Allouzi ◽  
Nasim Shatarat
Keyword(s):  
Structural Engineering ◽  
Experimental Tests ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Behaviour ◽  
Cross Sectional ◽  
Content Type ◽  
Flat Slabs ◽  
Reinforced Concrete Slabs ◽  
Rectangular Columns

PurposeThe main goal is to investigate the effect of size and location of opening and column size on the punching shear strength. Openings are often needed in order to install mechanical and electrical services. This process takes away part of the concrete volume which is responsible for resisting the shear forces and any unbalanced moment. Furthermore, the application of rectangular columns in flat slabs is commonly used in practice as they provide lateral stiffness to the building. They are also utilised in garages and multi-storey buildings where these elongated cross-sectional columns reduce the effective span length between adjacent columns.Design/methodology/approachThis research is a numerical-based investigation that is calibrated based on a thirteen previously tested and numerically calibrated slab specimens with no openings. A parametric study is conducted in this study to consider the effect of other parameters, which are the size and location of opening and the rectangularity ratio of column in order to evaluate their effect on the punching shear capacity. A total of 156 models are developed to study these factors. Additionally, the predicted shear carrying capacity of the simulated slabs is calculated using the ACI318–19 and Eurocode (EC2-04) equation.FindingsThe presence of openings reduced the punching shear capacity. The small opening's location and orientation have almost no effect except for one slab. For slabs of large openings, the presence of openings reduced the punching capacity. The punching capacity is higher when the openings are farther from the column. The numerically obtained results of slabs with rectangular columns show lower punching capacity compared to slabs of squared columns with the same length of the punching shear control perimeter. The punching capacity for all slabs is predicted by ACI318–19 and Eurocode (EC2-04) and it is found that Eurocode (EC2-04) provided a closer estimation.Originality/valueThe slabs considered for calibration were reinforced with four different punching shear reinforcement configurations, namely; ordinary closed rectangular stirrups, rectangular spiral stirrups, advanced rectangular spiral stirrups and circular spiral. Generally, there has been limited research on concrete flat slabs with openings in comparison with other subjects related to structural engineering (Guan, 2009) and no research on punching shear with openings of slabs reinforced with these reinforcement schemes. The available research focussed on the effects of openings on the flexural behaviour of reinforced concrete slabs includes Casadei et al. (2003), Banu et al. (2012) and Elsayed et al. (2009). In addition, experimental tests that examined slabs supported on rectangular columns are very limited.

SEISMIC PERFORMANCE OF GFRP-RC RECTANGULAR COLUMNS: NUMERICAL STUDY

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ehab El-Salakawy ◽  
Fangxin Ye ◽  
Yasser Mostafa Selmy
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Axial Load ◽  
Numerical Study ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Concrete Columns ◽  
Load Level ◽  
Reinforced Concrete Columns ◽  
Rectangular Columns

Composite materials like glass fiber-reinforced polymer (GFRP) is becoming widely acceptable to be used as a reinforcing material due to its high ultimate tensile strength-to-weight ratio and excellent resistance to corrosion. However, the seismic behavior of GFRP-reinforced concrete columns has not been fully investigated yet. This paper presents the results of a numerical analysis of full-size GFRP-RC rectangular columns under cyclic loading. The simulated column depicts the lower part of a building column between the foundation and the point of contra-flexure at the mid-height of the column. GFRP reinforcement properties and concrete modeling based on fracture energy have been incorporated in the numerical model. Experimental validation has been used to examine the accuracy of the constructed finite element models (FEMs) using a commercially available software. The validated FEM was used to perform a parametric study, considering several concrete strength values and axial load levels, to study its influence on the performance of the GFRP-reinforced concrete columns under cyclic loading. It was concluded that the hysteretic dissipation capacity deteriorates under high axial load level due to severe softening of the concrete. The FE results showed a substantial improvement of the lateral load-carrying capacities by increasing concrete compressive strength.

Behavior of Rectangular Columns with Low Lateral Confinement Ratio

2001 ◽  
pp. 977-984 ◽  
Author(s):  
S.S.E. Lam ◽  
B. Wu ◽  
Z.Y. Wang ◽  
Y.L. Wong ◽  
K.T. Chau
Keyword(s):  
Lateral Confinement ◽  
Rectangular Columns

scholarly journals Infrared Absorption Efficiency Enhancement of the CMOS Compatible Thermopile by the Special Subwavelength Hole Arrays

2020 ◽  
Vol 10 (8) ◽  
pp. 2966 ◽  
Author(s):  
Yun-Ying Yeh ◽  
Chih-Hsiung Shen ◽  
Chi-Feng Chen
Keyword(s):  
Infrared Absorption ◽  
Absorption Efficiency ◽  
Hole Array ◽  
Rectangular Hole ◽  
Efficiency Enhancement ◽  
Cmos Compatible ◽  
Subwavelength Hole Arrays ◽  
Hole Arrays ◽  
Difference Time ◽  
Rectangular Columns

The infrared absorption efficiency (IAE) enhancement of the complementary-metal-oxide-semiconductorCMOS compatible thermopile with special subwavelength hole arrays in an active area was numerically investigated by the finite-difference time-domain method. It was found that the absorption efficiency of that thermopile was enhanced when the subwavelength rectangular-hole array added extra rectangular-columnar or ellipse-columnar structures in the hole array. The simulation results show that the IAEs of the better cases for the three types of rectangular columns and three ellipse columns were increased by 14.4% and 15.2%, respectively. Such special subwavelength hole arrays can be improved by the IAE of the CMOS compatible thermopile.

Features of laminar and somatotopic organization of lumbar spinal cord units receiving cutaneous inputs from hindlimb receptive fields

1984 ◽  
Vol 52 (3) ◽  
pp. 449-458 ◽  
Author(s):  
A. R. Light ◽  
R. G. Durkovic
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Receptive Fields ◽  
Lumbar Spinal Cord ◽  
Spinal Neurons ◽  
Spinal Cord Neurons ◽  
Somatotopic Organization ◽  
Single Unit Recordings ◽  
Lumbar Spinal ◽  
Rectangular Columns

Single-unit recordings from 312 units of lamina I-VII of the lumbar spinal cord of unanesthetized, decerebrate, T8 spinal cats were used to determine the somatotopic and laminar organization of spinal neurons responding to cutaneous stimulation of the hindlimb. Properties of cells confined to different Rexed laminae (I-VII) were shown to differ in several respects, including responses to variations in stimulus intensity, receptive-field areas, spontaneous frequencies, and central delays. Spinal cord neurons with similarly localized cutaneous receptive fields were found to be organized in sagittally oriented rectangular columns. These columns were 7 to at least 20 mm long (rostral-caudal axis), 0.5-1.0 mm wide, and could encompass laminae I-VII in depth. Touch, pressure, and pinch were effective excitatory inputs into each column subserving a given receptive-field location. A map of the somatotopic organization of units in the horizontal plane is presented, which in general confirms previous reports and in particular deals with the organization of units with receptive fields on the plantar cushion and individual toes.

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