Strengthening of Two-way RC Slabs with Central Opening

The blast impact dynamic experiment of reinforced concrete rectangular plate with simply supported boundary conditions was performed using explosion pressure simulator. With 3-D FEM software LS-DYNA, the separate solid models of concrete and steel were established and 3-D FEM dynamic analysis of the experiment process was carried out. Compared calculation results to experiment results synthetically, the damage mechanism and failure characteristics of reinforced concrete plate under explosion impact loading condition were got and it is also verified that the H-J-C model can approximately simulate the concrete properties well under explosion impact loading condition.

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Critical shear crack theory-based punching shear model for FRP-reinforced concrete slabs

Advances in Structural Engineering ◽

10.1177/1369433220978146 ◽

2020 ◽

pp. 136943322097814

Author(s):

Xing-lang Fan ◽

Sheng-jie Gu ◽

Xi Wu ◽

Jia-fei Jiang

Keyword(s):

Shear Strength ◽

Reinforced Concrete ◽

Shear Crack ◽

Concrete Strength ◽

Weight Ratio ◽

Punching Shear ◽

Concrete Slabs ◽

Crack Theory ◽

Reinforced Concrete Slabs ◽

Rc Slabs

Owing to their high strength-to-weight ratio, superior corrosion resistance, and convenience in manufacture, fiber-reinforced polymer (FRP) bars can be used as a good alternative to steel bars to solve the durability issue in reinforced concrete (RC) structures, especially for seawater sea-sand concrete. In this paper, a theoretical model for predicting the punching shear strength of FRP-RC slabs is developed. In this model, the punching shear strength is determined by the intersection of capacity and demanding curve of FRP-RC slabs. The capacity curve is employed based on critical shear crack theory, while the demand curve is derived with the help of a simplified tri-linear moment-curvature relationship. After the validity of the proposed model is verified with experimental data collected from the literature, the effects of concrete strength, loading area, FRP reinforcement ratio, and effective depth of concrete slabs are evaluated quantitatively.

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Experimental investigation of the shear strength of one‐way reinforced concrete (RC) slabs subjected to concentrated loads and in‐plane transverse axial tension

Structural Concrete ◽

10.1002/suco.202100447 ◽

2021 ◽

Author(s):

Pablo G. Fernández ◽

Antonio Marí ◽

Eva Oller

Keyword(s):

Experimental Investigation ◽

Shear Strength ◽

Reinforced Concrete ◽

Concentrated Loads ◽

Axial Tension ◽

Plane Transverse ◽

Rc Slabs ◽

Transverse Axial

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Flexural strengthening of pre-cracked RC slabs with prestressed NSM CFRP laminates and evaluation of strain loss

Advances in Structural Engineering ◽

10.1177/13694332211010585 ◽

2021 ◽

pp. 136943322110105

Author(s):

M.R. Mostakhdemin Hosseini ◽

Salvador J.E. Dias ◽

Joaquim A.O. Barros

Keyword(s):

Carrying Capacity ◽

Load Carrying Capacity ◽

Limit States ◽

Transfer Length ◽

Rc Structures ◽

Cracked Concrete ◽

Flexural Strengthening ◽

Cfrp Laminates ◽

Load Carrying ◽

Rc Slabs

The strengthening intervention of RC structures often involves already cracked concrete. To evaluate the effect of the level of damage prior to the strengthening (pre-cracks) on the behavior of the flexurally strengthened RC slabs with prestressed NSM CFRP laminates, an experimental research was carried out. Two pre-cracking levels of damage were analyzed and, for each one, three levels of prestress were tested (0%, 20% and 40%). The obtained results showed that the strengthening of damaged RC slabs with prestressed NSM CFRP laminates results in a significant increase on the load carrying capacity at serviceability limit states. Pre-cracked RC slabs strengthened with prestressed NSM CFRP laminates presented a load carrying capacity almost similar to the corresponding uncracked strengthened slabs. To determine the effective prestress level in CFRP laminates, the variation of strain over the length of the CFRP and over time was experimentally recorded. The prestress transfer length was also evaluated. The experimental results revealed that the transfer length of CFRP laminates was less than 150 mm, and the maximum value of strain loss out of transfer length (around 14%) was measured close to the cracked section of the damaged RC slabs. Significant part of strain loss in CFRP laminates occurred during 24 h after releasing the prestress load.

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