A STRUT AND TIE MODEL FOR FRCM-STRENGTHENED REINFORCED CONCRETE DEEP BEAMS

Author(s):  
Tadesse Wakjira ◽  
Usama Ebead

Exiting literature revealed that fabric reinforced cementitious matrix (FRCM) is a promising material for the strengthening of shear deficient reinforced concrete (RC) beams. However, most of the available experimental studies are devoted to the use of FRCM system for the strengthening of slender beams and limited literature is available on the strengthening of deep beams using FRCM system. Moreover, there is no available literature on the analytical modelling of FRCM-strengthened deep beams. In this paper, a simple strut and tie model (STM) has been used to predict the ultimate load carrying capacity of RC deep beams strengthened in shear using FRCM system. The model accounts for the internal transverse reinforcement ratio and axial rigidity of the FRCM system. The proposed model is validated against an experimental results of RC deep beams strengthened with different types of FRCM system available in the literature.

2018 ◽  
Vol 21 (1) ◽  
pp. 86
Author(s):  
Ahmed Faleh Al-Bayati

This paper presents a simple strut and tie model to calculate the shear strength of reinforced concrete deep beams. The proposed model assumes that the shear strength is the algebraic sum of three strength components: concrete diagonal strut, vertical stirrups, and horizontal web reinforcements. The contribution of each strength components was calibrated with the test results of 305 deep beams compiled from previous studies with wide range of geometrical and material properties. The predictions of the proposed model were compared with those of the current codes of practice (ACI-318-14 and ASHTOO 2014) and those of existing model in the literature. Comparisons revealed that the proposed model provided better predictions than other models. The mean of predicted strength to test of the proposed model, the ACI-318-14 model, the ASHTOO 2014 model were 0.98, 0.79, and 0.75, respectively. The corresponding standard deviations were 0.17, 0.28, and 0.49, respectively.


2011 ◽  
Vol 243-249 ◽  
pp. 514-520
Author(s):  
Chun Yang ◽  
Ming Ji He ◽  
Jian Cai ◽  
Yan Sheng Huang ◽  
Yi Wu

Based on strut-and-tie model (STM) in deep beams, steel truss reinforced concrete (STRC) deep beam was developed. Experimental investigations of mechanical performances of STRC deep beams were carried out, and results show that STRC deep beam is of high ultimate bearing capacity, large rigidity and good ductility; Strut-and-tie force transference model is formed in STRC deep beams, and loads can be transferred in the shortest and direct way. Then Steel reinforced concrete (SRC) strut-and-tie model (SSTM) for determining the shear strength of STRC deep beams is proposed. The contribution of SRC diagonal strut, longitudinal reinforcements, stirrups and web reinforcements to the shear strength of STRC deep beams are determined with consideration of softened effects of concrete, and for safe consideration, superposition theory is employed for SRC struts. Computer programs are developed to calculate the shear strength of STRC deep beams and verified by experimental results.


2009 ◽  
Vol 7 (1) ◽  
pp. 97-109 ◽  
Author(s):  
Kil-Hee Kim ◽  
Woo-Bum Kim ◽  
Jin-Man Kim ◽  
Sang-Woo Kim

2019 ◽  
Vol 9 (17) ◽  
pp. 3637
Author(s):  
Haitao Chen ◽  
Lai Wang ◽  
Jitao Zhong

The optimal strut-and-tie models (STMs) of two typical irregular concrete deep beams were constructed using evolutionary structural optimization and compared with those of previous studies. The reinforced concrete deep beam specimens were cast according to the reinforcement designs guided by different STMs. Eight irregular concrete deep beam specimens were experimentally investigated under stepped loading, and the differences in the amount of steel used, the load-carrying capacity, and the failure pattern of the different specimens were analyzed. The results show that the optimal STMs proposed in this study have significant advantages in terms of cost-effectiveness and can simultaneously ensure the load-carrying capacity, delay the crack propagation of irregular concrete deep beams, and reduce the amount of steel used in structural members. Therefore, they have an important engineering application value for the reinforcement design of irregular concrete deep beams.


2014 ◽  
Vol 931-932 ◽  
pp. 473-477
Author(s):  
Prach Amornpinnyo ◽  
Jaruek Teerawong

This paper presents the test results on the shear behavior of reinforced concrete deep beams with six steel reinforcement configurations. They were designed in accordance with the method given in the ACI 318-11. The specimens were subjected to the single concentrated loading at mid-span. The horizontal to vertical reinforcement ratios and shear span-to-effective depth ratios were the variables studied. The shear span-to-effective depth ratios of the beam specimen were between 1.5 to 2.0. The strut-and-tie model was used for the analysis. The test results indicated that the first diagonal cracking load and the failure mode were controlled by the horizontal to vertical reinforcement ratios and the shear span-to-depth ratios. The tests consistently gave the strength values slightly less than those calculated by using the ACI model. A modified ACI model for strut-and-tie was thus proposed and was found to accurately fit the experimental results.


Sign in / Sign up

Export Citation Format

Share Document