Flexural Behaviour of Reinforced Concrete Members Subjected to Freeze-Thaw Cycles

2011 ◽  
Vol 71-78 ◽  
pp. 712-716
Author(s):  
An Duan ◽  
Wei Liang Jin

The purpose of this research is to investigate the influence of the freeze-thaw cycles on the flexural behavior of reinforced concrete members. The variation of the concrete stress-strain relationship due to frozen-thawed deterioration was considered. The temperature distribution was calculated based on the heat conduction theory, and the damaged region affected by freeze-thaw cycles was determined. By using Reponse-2000 program, the flexural behaviour of a reinforced concrete slab was analyzed and predicted. The analytical results show that with increase of number of freeze-thaw cycles, the yield moment, the ultimate moment and the curvature ductility decreased, while the relative depth of neutral axis and the midspan deflection increased.

2014 ◽  
Vol 7 (6) ◽  
pp. 940-964
Author(s):  
M. V. A. Lima ◽  
J. M. F. Lima ◽  
P. R. L. Lima

This work presents a model to predict the flexural behavior of reinforced concrete slabs, combining the Mazars damage model for simulation of the loss of stiffness of the concrete during the cracking process and the Classical Theory of Laminates, to govern the bending of the structural element. A variational formulation based on the principle of virtual work was developed for the model, and then treated numerically according to the Finite Difference Energy Method, with the end result a program developed in Fortran. To validate the model thus proposed have been simulated with the program, some cases of slabs in flexure in the literature. The evaluation of the results obtained in this study demonstrated the capability of the model, in view of the good predictability of the behavior of slabs in flexure, sweeping the path of equilibrium to the rupture of the structural element. Besides the satisfactory prediction of the behavior observed as positive aspects of the model to its relative simplicity and reduced number of experimental parameters necessary for modeling.


2017 ◽  
Vol 5 (1) ◽  
pp. 104-119
Author(s):  
Mazen D. Abdullah ◽  
Mustafa Sheriff ◽  
Aqeel Hateem

     This paper presents a study of the flexural behavior of strengthened and repaired reinforced concrete two slabs by ferrocement layers.  This study included testing 11 simply supported two way slabs, which include 1 control slabs, 8 strengthened slabs and 2 repaired slabs. In the strengthened slabs the effect of the thickness of ferrocement layers, the compressive strength for mortar and number of wire mesh layers of ferrocement on the ultimate load, mid span deflection at ultimate load and intensity of cracks was investigate. In the repaired part the slabs were loaded to (74 %) of measured ultimate load of control slab. The effect of connection method between repaired slabs and ferrocement jacket on the ultimate load, mid span deflection at ultimate load and intensity of cracks was examined. All reinforced concrete slab specimens were designed of the same dimensions and reinforce identically to fail in flexure. All slabs have been tested in simply supported conditions subjected to central concentrated load. The experimental results show that the ultimate loads are increased by about (4.6-19.2%) for the slabs strengthened with ferrocement with respect to the unstrengthened reinforced concrete slab (control slab).


2020 ◽  
Vol 23 (9) ◽  
pp. 1865-1879
Author(s):  
MI Sifan Mohamed ◽  
Julian Ajith Thamboo ◽  
Thuraisingam Jeyakaran

Semi-precast-reinforced concrete slab system offers more economic method of construction as it minimises the need of formwork at site. The assembly of semi-precast slab system involves two steps: (1) casting of semi-precast slab at the yard and (2) overtopping of concrete at the site. One of the main factors that influence the performance of such slab system is the interface bonding between precast and overtopping concrete. Therefore, in order to better understand the performance of this slab system, a research was carried out to investigate the influence of surface treatment methodologies to the overall flexural behaviour through experimental and numerical studies. In total, five representative semi-precast slabs were constructed and tested to assess the flexural performance with different surface preparation methods and concrete overtopping. Further small-scale precast with overtopped concrete couplets and triplets were casted and tested as the representative semi-precast concrete slab types to examine the interface shear and tensile bond strength characteristics with those different surface treatments. The experimental results revealed that the surface treatment methods have influenced the flexural behaviour of the slabs, where the interface shear bond strength exceeds more than 1.0 MPa and the slab system behaves monolithically under flexural action. Moreover, numerical modelling technique for this slab system was developed based on the finite element framework to further analyse the overall flexural behaviour. Subsequently, good agreements between experimental and developed numerical model results were found. Finally, parametric analyses were performed to further assess the influences of concrete strengths, spans and reinforcement ratios on the safe imposed pressure applicable for this slab system.


2021 ◽  
Vol 261 ◽  
pp. 02042
Author(s):  
Mingqiu Xu ◽  
Jianhua Shao ◽  
Baijian Tang ◽  
Hongming Li

Order to investigate the failure effect of textile reinforced concrete (TRC) plate under bending load, the corresponding finite element model is established. By comparing the numerical simulation results with the experimental results, the rationality and feasibility of the finite element model are verified, and then the crack extension of TRC and the ultimate strain of carbon textile are analyzed. The failure mode of the slab under bending load is obtained, and it is found that the carbon textile concrete slab has better reinforcement effect, which greatly improves the safety performance of concrete members.


2021 ◽  
Vol 21 (1) ◽  
pp. 179-187
Author(s):  
Jangsik Yoon ◽  
Byongjeong Choi

The yield or ultimate strength of a structure can be deteriorated by fire, leading to structural collapse. Temperature estimation has been studied in concrete members to identify the internal temperature distribution of reinforced concrete members at high temperatures. While foreign standards such as ACI 216 and Eurocode exist, no domestic standards have not been established for fire-resistant designs (temperature of components, strength reduction factor). This study discussed the temperature estimation and comparison of slab members using the methods of Hertz, Wickstrőm, Kodur, Eurocode, and ACI 216.1 and analyzed the differences from actual experiments by comparing reinforced concrete experiments, foreign standards, and existing studies.


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