Nonlinear finite element analysis of concrete structures (original) (raw)
Related papers
Construction and Building Materials, Vol. (84), PP 354-366, 2015
This paper presents an experimental, numerical and analytical study of the flexural behavior of concretebeams reinforced with locally produced glass fiber reinforced polymers (GFRP) bars. Glass fiber rein-forced polymers (GFRP) reinforcement bars has a lower stiffness than steel reinforcement, which shouldbe accounted for the ultimate and serviceability conditions, including the impact on member deflectionand crack widths. The bars are locally produced by double parts die mold using local resources raw mate-rials. A total of ten beams, measuring 120 mm wide 300 mm deep 2800 mm long, were cast andtested up to failure under four-point bending. The main parameters were reinforcement material type(GFRP and steel), concrete compressive strength and reinforcement ratio ( l b , 1.7 l b and 2.7 l b ; where l b is the reinforcement ratio at balanced condition). The mid-span deflection, crack width and GFRPreinforcement strains of the tested beams were recorded and compared. The test results revealed thatthe crack widths and mid-span deflection were significantly decreased by increasing the reinforcementratio. The ultimate load increased by 47% and 97% as the reinforcement ratio increased from l b to2.7 l b . Specimens reinforced by 2.7 l b can produce some amount of ductility provided by the concrete.The recorded strain of GFRP reinforcement reached to 90% of the ultimate strains. A non-linear finite ele-ment analysis (NLFEA) was constructed to simulate the flexural behavior of tested beams, in terms of crack pattern and load deflection behavior. It can be considered a good agreement between the experi-mental and numerical results was achieved. Modifications to ACI 440.1R-06 equation for estimatingthe effective moment of inertia ( I e ) of FRP-reinforced concrete beams, using regression analysis of experi-mental results, is proposed by introducing empirical factors that effectively decrease the I e at high loadlevel. The proposed equation is compared with different code provisions and previous models for predict-ing the deflection. It can proved that the proposed factors gives good estimation for the effective momentof inertia ( I e ) works well for FRP-reinforced concrete beams at high load level
As it is known, fiber reinforced polymer (FRP) bars are typically quite different from those of steel bars and they depend mainly on both matrix and fibers type, as well as on their volume fraction; although generally, FRP bars have lower weight, lower modulus of elasticity, but higher strength than steel. In the other hand, FRP has disadvantages, for instance: no yielding before brittle rupture and low transverse strength. In this research, we have investigated flexural behavior in reinforced concrete beams with bars from glass fiber-reinforced polymer (GFRP), bars from carbon fiber-reinforced polymer (CFRP) andbars from high tensile steel (HTS) under static load. We have analyzed the different kinds of failure, ultimate moment capacity, deflection, load of first crack, how to create and expand cracks, tensile and compressive strains created on beam during loading for different ratios of bars and different type of concrete strength. In the first group will show the effect of the type of reinforcement with different ratio of reinforcement .In the second group will show the effect of the type of reinforcement with different concrete strength. Results taken from the experimental tests have been compared with ACI 440 and they show that deflections, cracks pattern, mode of failure, strain diagrams, slip for all tested beams. Keywords: high performance concrete, bars from glass fiber reinforced polymer (GFRP), bars from carbon fiber reinforced polymer (CFRP), bars from high tensile steel (HTS) , static loading flexural behavior, ultimate moment, crack, deflection, strain, failure mode.
NUMERICAL AND ANALYTICAL EVALUATION OF CONTINUOUS CONCRETE BEAM REINFORCED WITH FRP BARS
IAEME Publications, 2021
An innovative promising non corrosive material to be used in reinforcing concrete structures has emerged; which is the Fiber Reinforced Polymers. It has been used as replacement for conventional steel reinforcement for several concrete structural members. Yet, some of these structural members have not been studied intensively, such as continuous beams. Continuous beams as structural elements might exist in residential, commercial buildings as well as bridges. This paper uses the continuous beam element to investigate the predicted equations for the crack widths and the deflection at the serviceability limit state SLS assigned by various codes and guidelines, a finite element model was established using ANSYS software. This model was validated against the experimental work done by El-Mogy,M. (2011) which is the foundation of this research. Various codes were adopted to estimate the deflection and the crack width against the verified ANSYS model to distinguish if any further modifications are required. The used codes in this study are the Egyptian Code of Practice ECP, the American Concrete Institute ACI guidelines and the Canadian Standards Association CSA. It was found that the American and the Canadian codes produced approximately the same results in the crack widths while modifications should be done in the Egyptian code in order to be used in designing structures and perform as the other ones that are similar to reality; it yielded a percentage of variance of more than 50 percent than the other codes which is an unacceptable percent while in the deflection calculations, non- satisfactory results were conducted from all the used codes in this study with maximum variance of 200 % yielded by the Canadian code; the results were precise but not accurate when compared to the ANSYS model.
Finite Element Simulation of GFRP Reinforced Concrete Beam Externally Strengthened With CFRP Plates
MATEC Web of Conferences, 2017
The construction technology now has become more and more advanced allowing the development of new technologies or material to replace the previous one and also solved some of the troubles confronted by construction experts. The Glass Fibre Reinforced Polymer (GFRP) composite is an alternative to replace the current usage of steel as it is rust proof and stronger in terms of stiffness compared to steel. Furthermore, GFRP bars have a high strength-to-weight ratio, making them attractive as reinforcement for concrete structures. However, the tensile behavior of GFRP bars is characterized by a linear elastic stress-strain relationship up to failure and, therefore, concrete elements reinforced with GFRP reinforcement exhibit brittle failure without warning. Design codes encourage over-reinforced GFRP design since it is more progressive and leads to a less catastrophic failure with a higher degree of deformability. Moreover, because of GFRP low modulus of elasticity, GFRP reinforced concrete members exhibit larger deflections and wider cracks width than steel reinforced concrete. This aims of this paper is to developed 2D Finite Element (FE) models that can accurately simulate the respond on an improvement in the deflection of GFRP reinforced concrete beam externally strengthened with CFRP plates on the tension part of beam. The prediction of flexural response according to RCCSA software was also discussed. It was observed that the predicted FE results are given similar result with the experimental measured test data. Base on this good agreement, a parametric study was the performed using the validation FE model to investigate the effect of flexural reinforcement ratio and arrangement of the beams strengthened with different regions of CFRP plates.
Nonlinear finite element analysis of full-scale concrete bridge deck slabs reinforced with FRP bars
Structures, 2020
Bridges with reinforced concrete deck slabs are more vulnerable to environmental-induced deterioration mainly due to corrosion. Carbon and glass fiber reinforced polymer (FRP) bars are getting attention as an alternative to steel bars to enhance the overall performance of the concrete bridge deck slabs and minimize corrosion-induced deteriorations. This study presents a 3D nonlinear finite element analysis (NLFEA) simulating the response of full-scale concrete bridge deck slabs reinforced with FRP bars. A control slab model was developed initially and properly calibrated and validated against published independent experimental results. A parametric study was then conducted through creating 27 NLFEA models with different parameters: concrete compressive strength, reinforcement type (glass FRP, carbon FRP, and steel), and bottom transverse reinforcement ratio. Monotonic single concentrated load was applied at the center of the concrete deck slab over a contact area of 600 mm × 250 mm, simulating the footprint of sustained truck wheel load. The CFRP and GFRP bars reinforcement of bridge deck slabs had superior effects on the ultimate load, elastic stiffness, post cracking stiffness, elastic energy absorption and post cracking energy and a little impact on ultimate deflection compared with steel reinforcement. Punching shear failure with a very similar cracking pattern was observed almost in all slabs and the bottom transverse reinforcement ratio is the main parameter affecting the tensile strains. For all slabs reinforced with GFRP and CFRP bars, the maximum measured strains in the bars at failure were less than 50% of their ultimate strain. Increasing concrete compressive strength will increase the ultimate load capacity and corresponding deflection of the slab. Recent research studies lead to the development of new generations of FRP bars consist of glass and carbon; i.e. glass fiber reinforced polymer (GFRP) bars and carbon fiber reinforced polymer (CFRP). These bars are considered innovation method to protect bridges and infrastructure systems from corrosion effects. The use of GFRP and CFRP was standardized through published CSA specifications (CAN/ CSA S807-10) and being produced with the highest possible quality [4]. The FRP bars are considered as an economical and effective alternative to traditional steel reinforcement for concrete infrastructures exposed
IRJET, 2021
Glass fiber reinforced polymer (GFRP) bars are now attracting as an alternative reinforcement in concrete beam because of their high resistance to corrosion that is a major problem for steel bars. A concrete beam is a structural element which carries load primarily in bending. Bending phenomenon causes a beam to undergo in tension and in compression. Beams carry vertical gravitational forces and can also be used to carry horizontal loads. These loads carried by beam are transferred to foundation. The beam compression section is designed to resist buckling and crushing, and tension section is designed to resist tension or flexure. Understanding the behaviour of concrete beam during loading is crucial for the development of an overall efficient and safe structure. This study presents the results of the comparison made between the predicted and the measured loaddeflection relationship for finding flexure strength by modeling of 12 concrete beam reinforced either by steel or GFRP bars. ANSYS 14.0 is used for modeling and analyzed the results obtained from the ANSYS 14.0 were compared with the theoretical.
Composite Structures, 2016
The paper presents the results obtained from a numerical and analytical analysis carried out on a set of concrete beams reinforced with steel bars, Fiber Reinforced Polymer (FRP) bars and hybrid combinations of FRP-steel bars. To this purpose a database of experimental results, available in literature, was collected. A simple and reliable two-dimensional Finite Element (FE) model was defined. In the numerical simulations, the linear and nonlinear behavior of all materials was adequately modeled by appropriate constitutive laws. To simulate the concrete post-cracking tensile behavior a specific tension stiffening model was used. In order to overcome convergence difficulties, to simulate the quasi-static response of RC beams, a dynamic approach was adopted. Furthermore, to assess the effectiveness of the current Italian guideline, on same set of RC beams, an analytical analysis was performed. The comparisons between numerical/analytical results and experimental data highlighted the reliability of both the proposed FE model and the analytical model. The results show that the tension stiffening model used in the FE analysis provides good results with low and normal reinforcement ratios, whereas the numerical predictions are not acceptable with high reinforcement ratios. The analytical results provided by the Italian guideline are satisfactory, compared to experimental data.
Evaluation of Concrete Structures Reinforced with Fiber Reinforced Polymers Bars: A Review
Journal of Asian Scientific Research, 2017
The behavior of concrete members reinforced with fiber reinforced polymer (FRP) bars has been the focus of many studies in recent years due to their excellent corrosion resistance, high tensile strength, and good non-magnetization properties. However, the low modulus of elasticity of the FRP materials and their non-yielding characteristics results in large deflection and wide cracks in FRP reinforced concrete members. This review was focusing in different behavior of FRP bars in reinforced concrete (RC) structures. Data and information collected in this review were gathered from the experimental, numerical and analytical studies from previous researches. Contribution/ Originality: This study contributes in the existing literature by investigate the behavior of FRP bars in reinforced concrete (RC) structures. Due to the increased use of FRP bars in concrete structures, the performance of FRP bars has been an important research topic in recent years. 1. INTRODUCTION Concrete structures are conventionally reinforced with steel bars and stirrups. Deterioration of RC structures due to corrosion of reinforcing steel bars is a major concern [1]. The corrosion problem of steel bar is the greatest factor in limiting the life expectancy of RC structures. Many environmental conditions accelerate the corrosion process of steel bar; thereby resulting in steady deterioration that decreases the life expectancy of these structures. In the last decade, considerable efforts have been made to apply FRP composites in the construction industry, and recently, structural applications of FRP composites started to appear in civil infrastructure systems [2]. FRP composite materials have been used as internal and external reinforcement in the field of civil engineering constructions [3]. Considerable research efforts have contributed to the understanding of concrete members internally reinforced with FRP bars [4]. These efforts, greatly improving our knowledge of how concrete members reinforced with FRP bars should be analyzed and designed in flexure and shear. In recent years, significant research efforts have shown that FRP materials can be effectively used to reinforce RC structures [5-7]. FRP reinforcement is made from high tensile strength fibers such as; aramid, carbon, and
Nonlinear Analysis of Reinforced Concrete Column with Fiber Reinforced Polymer Bars
In this paper, the results of an analytical investigation on the behaviour of RC columns reinforced with fibber reinforced polymer bars FRP are presented and discussed. Nonlinear finite element analysis on 10-column specimens was achieved by using ANSYS software. The nonlinear finite element analysis program ANSYS is utilized owing to its capabilities to predict either the response of reinforced concrete columns in the post-elastic range or the ultimate strength of a reinforced concrete columns reinforced by FRP bars. An extensive set of parameters is investigated including different main reinforcement ratios, main reinforcement types (GFRP, Steel), the transverse reinforcement ratios, and the characteristic compressive strength of concrete. A comparison between the experimental results and those predicted by the existing models are presented. Results and conclusions may be useful for designers, have been raised, and represented.