FINITE ELEMENT MODELLING OF 2-SPAN CONTINUOUS RC BEAMS SHEAR STRENGTHENED AND SHEAR REPAIRED WITH CFRP STRIPS

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Abdul Aziz Abdul Samad ◽  
Noorwirdawati Ali ◽  
Noridah Mohamad ◽  
J. Jayaprakash ◽  
Tuan Duc Ngo ◽  
...  

Strengthening of reinforced concrete (RC) continuous beams in shear have received very little attention among researchers even though most existing structures are in the form of continuous condition such as part of a floor-beam system. Therefore, in order to address the gap, a study on shear strengthening and shear repair of reinforced concrete continuous beam using Carbon Fibre Reinforced Polymer (CFRP) strips was conducted [15].  The validation of the experimental results was conducted with a simulation study using a finite element software ATENA v4 [16].  The research variables were number of layers of CFRP strips (one or two layers), wrapping schemes (four sides or three sides) and orientation of CFRP strips (0/90 or 45/135 degree’s). From the analysis of the finite element results, ATENA shows it has successfully simulated the shear behaviour of strengthened and repaired of 2-span continuous RC beams externally bonded by CFRP strips. 

2005 ◽  
Vol 32 (6) ◽  
pp. 1093-1102 ◽  
Author(s):  
Catalin Gheorghiu ◽  
Jamal Eddine Rhazi ◽  
Pierre Labossière

This paper reports on the potential of using the impact resonance method (IRM) for detecting fatigue damage in strengthened reinforced concrete (RC) beams. In this experimental program, 1.2 m long RC beams strengthened with a carbon fibre reinforced polymer (CFRP) plate have been employed. The specimens were subjected to fatigue loading under four-point bending for up to 2 × 106 cycles at 3 Hz. The load amplitude was varying from 15% to 75% of the cycles yielding load of the beam. Throughout fatigue testing, the cycling was stopped for IRM measurements to be taken. The obtained data provided information about changes in modal properties, such as, fundamental frequencies and damping ratios. Moreover, the results have shown that the IRM technique was successfully employed in laboratory for detecting fatigue damage in concrete beams strengthened with CFRP laminates.Key words: impact resonance method, modal properties, RC beam, FRP-strengthening, fatigue test, cracking.


2005 ◽  
Vol 32 (5) ◽  
pp. 812-824 ◽  
Author(s):  
Francesco Bencardino ◽  
Vincenzo Colotti ◽  
Giuseppe Spadea ◽  
Ramnath Narayan Swamy

The aim of this paper is to clarify the structural performance of reinforced concrete (RC) beams with weak or without any internal shear reinforcement and externally strengthened in flexure with carbon fibre reinforced polymer (CFRP) laminates, when subjected to a shear-dominant-loading regime. Seven RC beams were specifically designed, without and with an external anchorage system, which was carefully detailed to enhance the benefits of the strengthening laminate and counteract the destructive effects of shear forces. All the beams were identical in terms of their geometry, longitudinal internal reinforcement, and concrete strength but varied, to highlight the role of shear behavior, in terms of their internal and external shear reinforcement as well as in their loading test regime. The beams were tested under four-point bending and extensively instrumented to monitor strains, deflection, cracking, load carrying capacity, and failure modes. The structural response of the tested beams has, then, been critically analyzed in terms of deformability, strength, and failure processes that occur under a shear-dominant loading regime. It is shown that with a carefully designed anchorage system, a brittle behavior without yielding of tension steel reinforcement of a flexural strengthened beam can be transformed to a less brittle behavior with yielding of tension steel reinforcement and a well-defined enhancement of structural performance in terms of both deformation and strength. The results presented in this paper should enable engineers to counteract shear failure of externally strengthened beams with little or even no internal shear reinforcement.Key words: carbon fibre reinforced polymer, shear behavior, external flexural strengthening, structural performance.


2021 ◽  
Vol 347 ◽  
pp. 00038
Author(s):  
Mujtaba M. Shuaib ◽  
Steeve Chung Kim Yuen ◽  
Gerald N. Nurick

This paper reports on the results of a numerical study to simulate the response of carbon fibre reinforced polymer (CFRP) retrofitted steel plates to applied blast loads using finite element software, LS-DYNA. The results of the simulation were validated against plate response and magnitude of deformation obtained from previous experiments. The uniform blast load was generated in the experiment by detonating a cylindrical charge down the end of a square tube. The finite element code LS-DYNA was used to simulate the structural response of the respective blast structures. For the numerical model, the blast load was simulated using the mapping feature available in LS-DYNA for the multi-material arbitrary Lagrangian-Eulerian (MM-ALE) elements which significantly reduced the size of the air domain in the model. The simulations showed a satisfactory correlation with the experiments for the blast results and post-failure deformations that occurred in CFRP retrofitted steel plates.


Concrete, a mixture of different aggregates bonded with cement, first developed around 150BC in Rome has been bedrock to the modern Infrastructure. It is used to build everything from roads, bridges, dams to sky scrapers. Strengthening concrete is traditionally done by using steels but the developments in technology in recent decades allowed to use fiber reinforced plastics which are externally bonded to concrete . Such composite materials offer high strength, low weight, corrosion resistance, high fatigue resistance, easy and rapid installation and minimal change in structural geometry. This study investigates the behavior of reinforced concrete beams bonded with fiber composites. A numerical study is conducted to study the behavior of RC beam under Static third point loading. Concrete beam specimens with dimensions of 150 mm width, 300 mm height, and 2600 mm length are modelled. These beams are externally bonded with Glass Fiber Reinforced Polymer (GFRP) sheets and Carbon Fibre Reinforced Polymer (CFRP) sheets. In present study, we examine the performance of reinforced concrete beams which are bonded with GFRP and CFRP sheets with various thicknesses (1, 2 & 3 mm) using ABAQUS in terms of failure modes, enhancement of load capacity, load-deflection analysis and flexural behaviour


Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 520
Author(s):  
Daniel A. Pohoryles ◽  
Jose Melo ◽  
Tiziana Rossetto

Due to inadequacies of reinforcement design in older structures and changes in building codes, but also the change of building use in existing structures, reinforced concrete (RC) beams often require upgrading during building renovation. The combined shear and flexural strengthening with composite materials, fibre-reinforced polymer sheets (FRP) and textile reinforced mortars (TRM), is assessed in this study. An experimental campaign on twelve half-scale retrofitted RC beams is presented, looking at various parameters of interest, including the effect of the steel reinforcement ratio on the retrofit effectiveness, the amount of composite material used for strengthening and the effect of the shear span, as well as the difference in effectiveness of FRP and TRM in strengthening RC beams. Significant effects on the shear capacity of composite retrofitted beams are observed for all studied parameters. The experimental study is used as a basis for developing a detailed finite element (FE) model for RC beams strengthened with FRP. The results of the FE model are compared to the experimental results and used to design a parametric study to further study the effect of the investigated parameters on the retrofit effectiveness.


Author(s):  
Corneliu Bob ◽  
Sorin Dan ◽  
Catalin Badea ◽  
Aurelian Gruin ◽  
Liana Iures

<p>Many structures built in Romania before 1970 were designed for gravity loads with inadequate lateral load resistance because earlier codes specified lower levels of seismic loads. Some of these structures are still in service beyond their design life. Also, some deterioration was observed in existing structures due to the actions of different hazard factors. This paper presents the case study of a brewery with reinforced concrete framed structure of five storeys and a tower of nine storeys, which has been assessed and strengthened. The brewery and the tower were built in 1961 and an extension in 1971. An assessment performed in 1999 showed up local damages at slabs, main girders, secondary beams, and columns; concrete carbonation; concrete cover spalled over a large surface; complete corrosion of many stirrups and deep corrosion of main reinforcement; and some broken reinforcement. Such damage was caused by salt solution, CO2, relative humidity RH 80%, and temperatures over 40◦C. Also, inadequate longitudinal reinforcement was deduced≈ from the structural analysis. The initial design, done in 1960, was according to the Romanian codes of that time with provisions at low seismic actions. The structural system weakness is due to present-day high seismic actions. The rehabilitation of the reinforced concrete structure was performed by jacketing with reinforced concrete for the main and secondary beams and columns. In 2003, due to continuous operation and subsequent damage of the structure, a new assessment was required. It was found that some beams and one column were characterized by inadequate main and shear reinforcement as well as corrosion of many stirrups at beams. The strengthening solution adopted was based on carbon fibre reinforced polymer composites for beams and column.</p>


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