Strength of Concrete Struts in Three-Dimensional Strut-Tie Models

Yun, Young Mook; Ramírez, Julio A.

doi:10.1061/(asce)st.1943-541x.0001584

Cited by 8 publications

(3 citation statements)

References 2 publications

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“…This method designs the structural details based on the load distribution. Therefore, it facilitates the application of new designs unlike conventional empirical equations derived from experimental studies [15][16][17]. In this study, a strut-tie retrofit system was designed according to the loading distribution on the foundation elements (unlike conventional foundation members composed of concrete, flexural, and shear reinforcements) and applied on the foundation within the concrete.…”

Section: Strut and Tie Model Approachmentioning

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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Section: Strut and Tie Model Approachmentioning

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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“…However, the suggested equations and values are not consistent and general because they base on structural concretes with specific loading and geometric conditions. Yun & Ramirez [16] proposed a numerical method for determining the strut strengths in three-dimensional (3-D) structural concrete. The method accurately determines the stress levels of concrete struts for 3-D STM design situations.…”

Section: Introductionmentioning

confidence: 99%

Strengths of Struts and Nodal Zones for Strut-and-Tie Model Design of Reinforced Concrete Corbels

Yun

Lee

2021

Civ Eng J

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The strut-and-tie model (STM) method is useful for the limit state design of reinforced concrete (RC) corbels. However, for the rational design of RC corbels, designers must accurately determine the strengths of concrete struts and nodal zones to check the strength conditions of a selected STM and the anchorage of reinforcing bars in nodal zones. In this study, the authors suggested a numerical process for determining the strengths of concrete struts and nodal zones in RC corbel STMs. The technique incorporates the state of two-dimensional (2-D) stresses at the strut and nodal zone locations, 2-D failure envelope of concrete, deviation angle between the strut orientation and compressive principal stress trajectory, and the effect of concrete confinement by reinforcing bars. The authors also proposed the strength equations of struts and nodal zones that apply to the typical determinate and indeterminate STMs of RC corbels. The authors considered the effects of the shear span-to-effective depth ratio, the horizontal-to-vertical load ratio, and the primary tensile and horizontal shear reinforcement ratios in developing the strength equations. The authors predicted the failure strengths of 391 RC corbels tested to examine the appropriateness of the proposed numerical process and strength equations. The predicted failure strength compares very well with experimental results, proving that the rational analysis and design of RC corbels are possible by using the present study's strut and nodal zone strengths. Doi: 10.28991/cej-2021-03091725 Full Text: PDF

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“…Abdul-Razzaq and Farhood [9] designed and manufactured 12 RC cap specimens with different number of piles, comparatively studied the difference of bearing capacity and failure mechanism of the specimens designed according to the traditional section design method and the STM, and pointed out the shortcomings of cap design in ACI 318. Existing research on the application of STM mainly focused on the few pile caps, although STM was modified and improved by model tests and FEM, and a higher precision STM was proposed [2,[10][11][12][13][14][15][16]. In the literature, the compatibility and tensile contributions of concrete materials [2], modifying the node and tie parameters [14], the size effect (decreasing strength while increasing member size) [15], or the constitutive laws and strain compatibility of cracked reinforced concrete [10] were considered.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Behavior and Calculation Method for RC Fifteen‐Pile Cap of Mixed Passenger and Freight Railway Bridge

Huang

Cui²,

2020

Advances in Civil Engineering

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The thickness, reinforcement, and concrete strength grade of railway caps in China are generally determined according to the force, yet the method for calculating the force is unclear. To date, there is no desirable calculation method for analyzing the caps. Based on the fifteen-pile thick cap of mixed passenger and freight railway, the influencing factors on cap bearing capacity were analyzed using finite element method (FEM). The variations of load-bearing capacity and mechanical behavior of thick cap were characterized by introducing rigid angle α. Results indicated that ultimate load-bearing value of the cap increased linearly with the increase of concrete strength grade, and an increasing load-bearing capacity of the reinforcement distributed in the pile diameter range was larger than that of the uniform reinforcement; when the reinforcement ratio was 0.15%, it increased by 9.3%. The cap showed punching failure when α < 45°. The reaction force at each pile top under vertical load was not equal; thereby, the cap was not absolutely rigid. The principal compressive stress trajectories in the concrete were distributed in the range of connecting the pile and the outer edge of the pier, and the effective tensile stresses in the reinforcement were mainly distributed in the diameter range of pile and pile connection, which is in accord with the stress mode of the ordinary spatial truss model. Based on this, a spatial truss model applicable to the design of railway caps is proposed, and a method for calculating reaction force at pile top and formulas for calculating the bearing capacity of strut and tie were presented. The feasibility of the proposed method was also verified by comparison with FEM results.

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Strength of Concrete Struts in Three-Dimensional Strut-Tie Models

Cited by 8 publications

References 2 publications

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

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

Strengths of Struts and Nodal Zones for Strut-and-Tie Model Design of Reinforced Concrete Corbels

Mechanical Behavior and Calculation Method for RC Fifteen‐Pile Cap of Mixed Passenger and Freight Railway Bridge

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