An Indeterminate Strut-Tie Model and Load Distribution Ratio for RC Deep Beams - (I) Model &amp; Load Distribution Ratio

Kim, Byung-Hun; Yun, Young Mook

doi:10.1260/1369-4332.14.6.1031

Cited by 17 publications

(6 citation statements)

References 12 publications

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“…According to Herranz et al (2012), the design of the STM should comply with three recommendations: (i) to comply with static equilibrium, (ii) to have enough strength in ties, struts and nodes, and (iii) to be an isostatic model. It is important to emphasize that this last recommendation is not mandatory, but aims at simplifying the calculation of forces, so it is possible to propose indeterminate models such as those studied by Kim & Yun (2011).…”

Section: Strut and Tie Modelmentioning

confidence: 99%

Optimized design of RC deep beams based on performance metrics applied to strut and tie model and in-plane stress conditions

Santos

Neto

Reginato

et al. 2019

Lat. Am. j. solids struct.

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Deep beams do not behave according to classical beam theory. The nonlinearity of strain distribution within these elements requires application of strut and tie models (STM) or other alternatives to evaluate the complex stress field. Although the design of these elements is a common task for structural engineers, limited research is found on assessing effectiveness of the results. The purpose of this work is to compare, in a systematic approach, different design solutions for a deep beam using selected performance metrics which are strain energy, reinforcement ratio, maximum load, structural efficiency, safety factor and cracking behavior. A deep beam (2.85 m of height, 4.20 m of length and 0.2 m of thickness) with a square opening (0.7 m x 0.7 m) close to one of the supports was subjected to a uniform loading at the top surface while resting on supports at both ends. A simplified finite element model (FEM) of this beam was developed simulating concrete with elastic linear stress-strain behavior and disregarding steel reinforcements. This model allowed determination of elastic stress fields necessary to subsequent analyses. Four STM were then developed, supposing the total load respectively represented by one (STM-1), two (STM-2), four (STM-4) or eight (STM-8) concentrated loads equally spaced along the top of the beam. Additionally, an in-plane stress field method (SFM) was applied to the design of the same beam subjected to uniform loading on the top surface. After design and detailing of the reinforcement for each situation, nonlinear FEMs were used to predict the ultimate conditions. The strain energy reduced significantly comparing results from STM-1 to STM-2 and subsequently to STM-4 and remained at a low level in STM-8 and SFM. The reinforcement ratio reduced systematically from STM-1 to STM-8, was minimum with the SFM and the same behavior was followed by maximum load. The structural efficiency (maximum load/reinforcement ratio) increased from STM-1 to STM-8, with maximum efficiency at STM-8 and was slightly below with SFM. The safety factor reduced systematically from STM-1 to STM-8 and was slightly lower with SFM, but in all cases was above acceptable limits found in design codes.

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Section: Strut and Tie Modelmentioning

confidence: 99%

Optimized design of RC deep beams based on performance metrics applied to strut and tie model and in-plane stress conditions

Santos

Neto

Reginato

et al. 2019

Lat. Am. j. solids struct.

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“…The sectional method of CSA (CSA, 2012) can also be used for beams with a / d between 1.0 and 2.5, which are considered as deep beam. Also, Kim and Yun (Kim and Yun, 2011) mentioned that the ratio of shear span to depth, reinforcement ratio, and compressive strength of concrete control the behavior of deep beams. Therefore, the aim of this study is to examine the STM and sectional methods of CSA and ACI design provisions to predict the shear capacity of FRP reinforced DBs, to find a more exact solution using ACI and CSA sectional equations and to propose a simple method to predict shear resistance of FRP reinforced deep members.…”

Section: Introductionmentioning

confidence: 99%

Proposed prediction models for shear strength of fiber reinforced polymer reinforced concrete deep members without stirrups

Alam

2023

Advances in Structural Engineering

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Arch action in deep reinforced concrete (RC) members has a beneficial effect on shear capacity. The Strut-and-Tie Method (STM) is one of the proposed methods for the design of steel reinforced deep beams (DBs). However, some iterations may require to obtain the optimum solution. This paper investigates the shear capacity of fiber reinforced polymer (FRP)-reinforced DBs using STM and sectional methods of Canadian Standard Association (CSA) and American Concrete Institute (ACI) design provisions. To this end, 106 FRP-reinforced DBs were compiled from the literature. It has been found that current sectional methods do not adequately account for the effects of arch. action on DBs. From this investigation, modifications were proposed in the current sectional methods to calculate the shear capacity of FRP-reinforced DBs. The proposed modifications were found to significantly improve the prediction accuracy. The sectional methods proposed by CSA and ACI were found to be better than the CSA-STM method in predicting the shear capacity of FRP-reinforced DBs.. The mean, standard deviation and coefficient of variation for the proposed CSA sectional method are 1.00, 0.28 and 28.2% and for the proposed ACI sectional method are 1.01, 0.26 and 25.6, respectively. The same for the CSA-STM method are 2.20, 0.76 and 34.4%, respectively. The proposed methods can be used to predict the shear capacity of FRP reinforced deep members.

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“…The increased loads, in turn, increased the thickness of the foundation members. In particular, the foundation members that resisted various loading types (e.g., axial force, shear force, and bending moment) acting on the column bases suffered from stress concentration, which contributed to an increase in the thickness of the foundation [1,2].…”

Section: Introduction 1backgroundmentioning

confidence: 99%

Investigation of Load-Bearing Capacity for Reinforced Concrete Foundation Retrofitted Using Steel Strut–Tie Retrofit System

Shin

Lee

2023

Sustainability

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To reduce the thickness of reinforced concrete foundation members used in construction and structural applications, a previous study developed and tested a strut–tie retrofit system installed in the foundations. This study proposes the optimum retrofit details of a steel-tie retrofit system for foundation members with reduced thickness via a finite element simulation-based load-bearing capacity assessment. The retrofit parameters (structural steel type, plate thickness, and number of strut frames) that significantly affected the load-bearing capacities were optimized by comparing the maximum effective stress and code-defined allowable stress limits. The optimum retrofit details were compared with those computed using a code-defined strut–tie model. Based on the load-bearing capacity assessment for the design of loading combinations, the optimum retrofit details can be reduced in transverse (by 55%) and longitudinal (by 87%) directions compared with those designed using the strut–tie model approach.

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An Indeterminate Strut-Tie Model and Load Distribution Ratio for RC Deep Beams - (I) Model & Load Distribution Ratio

Cited by 17 publications

References 12 publications

Optimized design of RC deep beams based on performance metrics applied to strut and tie model and in-plane stress conditions

Optimized design of RC deep beams based on performance metrics applied to strut and tie model and in-plane stress conditions

Proposed prediction models for shear strength of fiber reinforced polymer reinforced concrete deep members without stirrups

Investigation of Load-Bearing Capacity for Reinforced Concrete Foundation Retrofitted Using Steel Strut–Tie Retrofit System

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