scholarly journals Teoría y experiencias en el incremento de ductilidad de los hormigones de alta resistencia reforzados con fibras de acero.

2012 ◽  
Vol 2 (3) ◽  
pp. 131-148
Author(s):  
Manuel Fernández Cánovas
Keyword(s):  
Reinforced Concrete ◽  
High Strength Concrete ◽  
High Strength ◽  
Offshore Structures ◽  
Blast Waves ◽  
Steel Fibers ◽  
Structural Elements ◽  
Gas Reservoirs ◽  
Strength Concrete ◽  
Impulsive Loads

RESUMENLas acciones de impacto y cargas impulsivas provocadas por misiles o choque de aeronaves sobre edificios de contención de reactores nucleares o sobre grandes depósitos de almacenamiento de gas licuado, o de vehículos o buques contra pilas de puentes, plataformas petrolíferas marinas, etc., o de ondas explosivas sobre edificios civiles o militares, siempre han tenido una gran importancia en ingeniería, pero las tienen más en estos últimos tiempos debido a la proliferación de actos terroristas. Las estructuras sometidas a estas acciones deben presentar un comportamiento diferente a las tradicionales debido a las grandes cantidades de energía que tienen que absorber y disipar en tiempos muy cortos, de aquí que los elementos estructurales formados por hormigón y acero, tengan que poseer una ductilidad suficiente para que mediante grandes deformaciones anelásticas no llegue a colapsar. En experiencias realizadas frente a acciones dinámicas parecidas a las provocadas por los sismos o a la acción de explosivos o de impacto de proyectiles hemos podido comprobar como el confinamiento de los elementos estructurales conseguido con armadura tradicional y fibras de acero puede producir una ductilidad notable. Este artículo tiene por objeto presentar los resultados de algunos trabajos de investigación en los que se muestra el comportamiento de elementos de hormigón armado reforzado con fibras de acero frente a este tipo de acciones.Palabras clave: ductilidad; impacto; cargas impulsivas; sismos; hormigón de alta resistencia; fibras de acero; cráter de salida.ABSTRACTImpact and impulsive loads such of those caused by missile and aircraft impact on nuclear containers or big liquated gas reservoirs, vehicles or ships in collision with bridges piles or offshore structures, or by blast waves on civil and military buildings or shelters, have played an important role in civil engineering, but today these actions reach a transcendental role because the proliferation of terrorist menaces. The behaviour of structures under these actions must be different of traditional ones, because of the big quantity of energy they must absorb and dissipate in a very short time, so structural elements formed by reinforced concrete must have ductility enough to reach large anelastic strains without failure. In tests carried out by us in high strength concrete structural elements under impact of projectiles or dynamic actions, similar to those produce by seismic movements, we have checked how with a confinement by means of steel stirrups with the complement of steel fibers is possible to reach a notable ductility. The goal of this article is to present the results of some research works carried out showing the behaviour of reinforced concrete with steel fibers elements against these type of actions.Keywords: ductility; impact; impulsive loads; earthquake; high strength concrete; steel fibers; scabbing.

Seismic Performance of High Titanium Heavy Slag High Strength Concrete Columns

2012 ◽  
Vol 174-177 ◽  
pp. 455-459 ◽  
Author(s):  
Xiao Wei Li ◽  
Xue Wei Li ◽  
Xin Yuan
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
High Strength Concrete ◽  
Load Ratio ◽  
High Strength ◽  
Scale Model ◽  
Transverse Reinforcement ◽  
Reinforced Concrete Column ◽  
Displacement Ductility ◽  
Strength Concrete

For expedite the development of high titanium heavy slag concrete, eight high titanium heavy slag high strength reinforced concrete (HTHS-HSRC) scale model column are studied. The eight HTHS-HSRC model columns are tested under reversed horizontal force. Primary experimental parameters include axial load ratio varying from 0.3 to 0.5, volumetric ratios of transverse reinforcement ranging from 1.38% to 1.56%, strength of high titanium heavy slag high strength concrete varying from 55.9 to 61.6 N/mm2 and configurations of transverse reinforcement. It is found from the test result that HTHS-HSRC model columns provides comparable seismic performance to those usually used reinforced concrete column in terms of member ductility, hysteretic and energy dissipation capacity. Primary Factors of Displacement Ductility of Model Columns are also discussed.

scholarly journals Transverse Deformations and Structural Phenomenon as Indicators of Steel Fibred High-Strength Concrete Nonlinear Behavior

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Iakov Iskhakov ◽  
Yuri Ribakov
Keyword(s):  
High Strength Concrete ◽  
High Efficiency ◽  
Limit State ◽  
Nonlinear Behavior ◽  
High Strength ◽  
Steel Fibers ◽  
Ultimate Limit State ◽  
Strength Concrete ◽  
Brittle Behavior ◽  
Ductile Behavior

As known, high-strength compressed concrete elements have brittle behavior, and elastic-plastic deformations do not appear practically up to their ultimate limit state (ULS). This problem is solved in modern practice by adding fibers that allow development of nonlinear deformations in such elements. As a rule, are applied steel fibers that proved high efficiency and contribute ductile behavior of compressed high-strength concrete (HSC) elements as well as the desired effect at long-term loading (for other types of fibers, the second problem is still not enough investigated). However, accurate prediction of the ULS for abovementioned compression elements is still very important and current. With this aim, it is proposed to use transverse deformations in HSC to analyze compression elements' behavior at stages close to ultimate. It is shown that, until the appearance of nonlinear transverse deformations (cracks formation), these deformations are about 5-6 times lower than the longitudinal ones. When cracks appear, the tensile stress-strain relationship in the transverse direction becomes nonlinear. This fact enables to predict that the longitudinal deformations approach the ultimate value. Laboratory tests were carried out on 21 cylindrical HSC specimens with various steel fibers content (0, 20, 30, 40, and 60 kg/m3). As a result, dependences of transverse deformations on longitudinal ones were obtained. These dependences previously proposed by the authors’ concept of the structural phenomenon allow proper estimation of the compressed HSC state up to failure. Good agreement between experimental and theoretical results forms a basis for further development of modern steel fibered HSC theory and first of all nonlinear behavior of HSC.

Mechanical Properties of HPC and Numerical Simulation of Mine Shaft under 3D Load

2015 ◽  
Vol 777 ◽  
pp. 48-51
Author(s):  
Hui Cao ◽  
Lin Lin Jiang
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Strength Concrete ◽  
Effective Strain ◽  
Earth Pressure ◽  
High Strength ◽  
Wall Structure ◽  
Concrete Wall ◽  
Mine Shaft ◽  
Strength Concrete

The mechanical properties of high-strength concrete was studied in the laboratory, and obtained a high strength concrete uniaxial compressive strength changes with curing period, found that low temperature curing C100 Poisson's ratio of concrete is 0.24, and elastic modulus reached about 52.5GPa. The test results are applied to the numerical calculation, established a separate type reinforced concrete wall, and the multiaxial loading the stress state is simulated, the research shows that it is applied to C100 reinforced concrete shaft lining under its own gravity and the surrounding soil earth pressure, the maximum effective stress are respectively 25MPa , and effective strain is 4E-4mm, structure of shaft wall failure caused by shear wall structure. Under the three state of compression, the strength of concrete is improved.

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