scholarly journals Serviceability of Post-fire RC Rafters with Openings of Different Sizes and Shapes

2022 ◽  
Vol 28 (1) ◽  
pp. 19-32
Author(s):  
Bashar Abdulkareem ◽  
Amer F. Izzet
Keyword(s):  
Reinforced Concrete ◽  
Static Loading ◽  
Heating Temperature ◽  
Moment Of Inertia ◽  
Reinforced Concrete Beams ◽  
Concentrated Force ◽  
Calculation Technique ◽  
Different Shapes ◽  
The Moment ◽  
Good Agreement

This study deals with the serviceability of reinforced concrete solid and perforated rafters with openings of different shapes and sizes based on an experimental study that includes 12 post-fire non-prismatic reinforced concrete beams (solid and perforated). Three groups were formed based on heating temperature (room temperature, 400 °C, and 700 °C), each group consisting of four rafters (solid, rafters with 6 and 8 trapezoidal openings, and rafter with eight circular openings) under static loading. A developed unified calculation technique for deflection and crack widths under static loading at the service stage has been provided, which comprises non-prismatic beams with or without opening exposed to flexure concentrated force. Two approaches were used to compute the deflection: The first attempt was conducted by using the moment of inertia for solid non-prismatic beam and reduced for those with openings by the ratio of residual rafter self-weight. The second was performed by using the moment of inertia of transformed cracked sections depending on the segmental rafter method. The crack width was determined using the ACI code's equation. The analytical and experimental results were evaluated and found to be in good agreement.

scholarly journals Serviceability of Reinforced Concrete Gable Roof Beams with Openings under Static Loads

2019 ◽  
Vol 9 (5) ◽  
pp. 4813-4817
Author(s):  
M. A. J. Hassan ◽  
A. F. Izzet
Keyword(s):  
Reinforced Concrete ◽  
Static Loading ◽  
Analytical Study ◽  
Magnification Factor ◽  
Concentrated Force ◽  
Static Loads ◽  
Gable Roof ◽  
Direct Stiffness ◽  
Crack Widths ◽  
Good Agreement

This paper presents an analytical study on the serviceability of reinforced concrete gable roof beams with openings of different sizes, based on an experimental study which includes 13 concrete gable roof beams with openings under static loading. For deflection and crack widths under static loading at service stage, a developed unified calculation procedure has been submitted, which includes prismatic beams with one opening subjected to flexure concentrated force. The deflection has been calculated with two methods: the first method calculated deflections via relevant equations and the second was Direct Stiffness Method in which the beam is treated as a structural member with several segments constituting the portions with solid sections and those with sections crossed by the opening. The crack width was calculated with the ACI code’s equation with a proposed magnification factor equal to 1.125. The analytical results were compared with the experimental ones and a good agreement was obtained.

In-Plane Force Effect of Reinforced Concrete Beam with Elastic Supports

2011 ◽  
Vol 287-290 ◽  
pp. 1896-1901
Author(s):  
Zhi Kun Guo ◽  
Wan Xiang Chen ◽  
Qi Fan Wang ◽  
Yu Huang ◽  
Chao Pu Li ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Nonlinear Characteristics ◽  
Elastic Supports ◽  
Calculation Results ◽  
Basic Equations ◽  
First Time ◽  
Good Agreement

The bearing capacities of one-way reinforced concrete beams with elastic supports are investigated in this paper. According to the nonlinear characteristics of the beams, the basic equations based on plastic theory of concrete are derived by considering the in-plane force effects that aroused by the constraints of supports when the beams deforming. It is indicated that the calculation results are in good agreement with experimental datum, and the influences of different supports on the bearing capacities of the beams are quantitatively given for the first time.

scholarly journals Assessing the Instantaneous Stiffness of Cracked Reinforced Concrete Beams Based on a Gradual Change in Strain Distributions

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Chunyu Fu ◽  
Dawei Tong ◽  
Yuyang Wang
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beams ◽  
Internal Force ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Gradual Change ◽  
Concrete Cracking ◽  
Good Agreement

Concrete cracking causes a gradual change in strain distributions along the cross section height of reinforced concrete beams, which will finally affect their instantaneous stiffness. A method for assessing the stiffness is proposed based on the gradual change, which is considered through modeling different strain distributions for key sections in cracked regions. Internal force equilibria are adopted to find a solution to top strains and neutral axes in the models, and then the inertias of the key sections are calculated to assess the beam stiffness. The proposed method has been validated using experimental results obtained from tests on five reinforced concrete beams. The predicted stiffness and displacements are shown to provide a good agreement with experimental data. The instantaneous stiffness is proven to greatly depend on the crack number and depth. This dependence can be exactly reflected by the proposed method through simulating the gradual change in concrete strain distributions.

Calculation of Flexural Capacity of High-Strength Reinforced Concrete Beams Strengthened with FRP

2011 ◽  
Vol 71-78 ◽  
pp. 815-817 ◽  
Author(s):  
Jiong Feng Liang ◽  
Ze Ping Yang ◽  
Zhi Ming Qiu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Engineering Application ◽  
High Strength ◽  
Correlation Equation ◽  
Reinforced Concrete Beams ◽  
Flexural Capacity ◽  
Different Types ◽  
Fiber Reinforce ◽  
Good Agreement

The mechanical properties of high-strength reinforced concrete beams strengthened with FRP ( fiber reinforce polymer) are further investigated theoretically including it s failure mechanism and loadability,based on earlier theoretical works on RC beams. And the correlation equation of flexural capacity on the cross section of high-strength reinforced concrete beams strengthened with FRP is deduced according to different types of failure.The correlation equation is shown to be in good agreement with the experimental results, which can be referred to engineering application.

scholarly journals Reinforced concrete beams coated with fiberglass-reinforced polymeric profiles as partial substitutes for the transverse reinforcement

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Igor Souza Hoffman ◽  
Jorge Henrique Piva ◽  
Augusto Wanderlind ◽  
Elaine Guglielmi Pavei Antunes
Keyword(s):  
Reinforced Concrete ◽  
Composite Structures ◽  
Mechanical Performance ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Transverse Reinforcement ◽  
Structural Applications ◽  
The Moment ◽  
The One

abstract: The use of GFRP (Glass Fiber Reinforced Polymers) structural profiles in the construction sector is growing due to their attractive properties, such as high mechanical strength and durability in aggressive environments. With this, it is necessary to conduct studies that deepen the knowledge about the performance of these materials in structural applications. Therefore, this work aims to analyze the mechanical performance of reinforced concrete beams coated with GFRP profiles, in comparison to reinforced concrete beams, by analyzing groups with different spacing between transversal reinforcement. In all groups there was no change in the longitudinal reinforcement, and the D and Q groups were, respectively, made up of transverse reinforcement spaced twice and quadruple the one calculated for the reference beams, and presented the GFRP profiles in their constitution. All beams were tested at four-point bending, and strain gauges were installed in one of the beams of each group studied. The results obtained in the tests showed an increase in strength of 83.67% in the beams of group D, and 79.91% for group Q, in relation to the references. The analysis of longitudinal deformations made it possible to verify increases in stiffness and the moment of cracking in composite beams. Thus, based on this study, the composite structures studied may constitute future solutions for constructions exposed to aggressive environmental conditions, in order to increase their durability and also to contribute to the design of such structural elements with lower reinforcement rates.

scholarly journals Behaviour of Reinforced Concrete Beams with and Without Web Openings using Direct Displacement Based Design

2021 ◽  
Vol 2117 (1) ◽  
pp. 012006
Author(s):  
I Komara ◽  
C B Casita ◽  
E Susanti ◽  
D Pertiwi ◽  
D K Fitriah ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Analytical Modelling ◽  
Reinforced Concrete Beams ◽  
Structural Members ◽  
Web Openings ◽  
Direct Displacement Based Design ◽  
Service Load ◽  
Displacement Based ◽  
Support Reactions ◽  
Good Agreement

Abstract This paper describes analysis at the reinforced concrete building that contain web openings at the beam element in certain location. In the analytical modelling, the beams as treated as structural members comprising several segments which has a different dimension, and the equivalent stiffness of the opened beams has been derived. The whole structure including the beams are then analysed by the direct displacement based designed method. As the result from three analytical modelling within the variety of web openings and literature studies are compared with the evaluation of deflections and support reactions under service load. A numerical modelling is also supported the study to corroborate findings. In general, a good agreement has been obtained.

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