Efficiency of stiffening plates in fabricated concrete-filled tubes under monotonic compression

Albareda-Valls, Albert; Carreras, Jordi Maristany

doi:10.12989/scs.2015.18.4.1023

Cited by 8 publications

(7 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The constitutive models for both steel and concrete which has been used in this analysis were calibrated in other occasions by the same authors [1], by taking plasticity criteria into account for both materials. For steel, an elasticplastic model with isotropic plasticity has been implemented, while the CDP model (Concrete Damage Plasticity) has been used for concrete, being sensitive to hydrostatic pressure [2][3][4].…”

Section: Materials Modelsmentioning

confidence: 99%

Analysis of slab-column connections in CFT sections without continuity of the tube

Albareda-Valls

Carreras

Carrera

2018

Proceedings 12th International Conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018

Self Cite

View full text Add to dashboard Cite

When dealing with concrete-filled tube columns and RC slabs, it is usual to interrupt steel tubes in slab-column connections if the column is mainly compressed. Contractors do prefer to solve these connections with independent tubes, although innerreinforcements may be continuous through the slab. In these cases, both tubes from the upper and lower levels do have base plate connections, with a set of anchor bolts. This procedure saves a lot of time of global works, by making everything easier at the same time, as tubular profiles do not intersect the formwork.However, this reasonable design for slab-column joints suggest at least some questions about the strength of the concrete at the area of connection, where the tube has been interrupted. On the one hand, the load is transferred through concrete in the slab thickness, since there is no continuity of the tube; on the other hand, concrete at that point becomes triaxially confined due to the restriction to lateral deformation.This study analyses the validity of this connection method and the differences observed depending on the relative location of the column (corner, façade –lateral- or central pillars). Needless to say that the relative location of the column leads to differentconfinement patterns in concrete.

show abstract

Section: Materials Modelsmentioning

confidence: 99%

Analysis of slab-column connections in CFT sections without continuity of the tube

Albareda-Valls

Carreras

Carrera

2018

Proceedings 12th International Conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…According to the boundary conditions in a uniform compressed tube, the effects of local buckling usually appear in the nearby of the two edges [2]. According to the boundary conditions in a uniform compressed tube, the effects of local buckling usually appear in the nearby of the two edges [2].…”

Section: Local Buckling Of Cft Sections According To Eurocodementioning

confidence: 99%

“…The material models for steel and concrete used in this analysis were calibrated in other occasions by the same authors [2], by taking into account plasticity criteria in steel. An elastic model with isotropic plasticity for metals has been implemented in steel, while concrete has been considered as completely elastic with a limit for the tensile strength.…”

Section: Materials Modelsmentioning

confidence: 99%

See 1 more Smart Citation

08.46: Local buckling of thin‐walled tubes encased in concrete

2017

Self Cite

View full text Add to dashboard Cite

Local buckling of concrete-filled tubes has been studied by several researchers these recent years, due to the evidence that the limits provided by the Eurocode for considering local buckling in steel tubular sections are non-conservative, especially when taking the confinement effect of concrete into account. In CFT (concrete-filled tube) sections, lateral pressure provided by concrete when loading both components at the same time leads to a reduction of stability of the cylindrical shell in terms of local buckling, since it is subjected to a vertical and lateral pressure. However, this phenomenon has exactly the opposite effect when the encased component is the steel tube; this is the case of concrete-encased tubes, a very interesting typology for its mechanical and fire response. In these sections, the encased tube is subjected to a uniform compressive pressure from outside that clearly enhances the stability of the shell; this study presents a numerical and analytical approach to local buckling in these sections, by using a complex numerical model calibrated with real thin and thick-walled previous experiments. The conclusions of this text pretend to describe the efficiency of these sections in terms of local buckling, and to fix the base for a wide experimental and numerical campaign to determine how each parameter may influence to the global response.

show abstract

“…The length of the analyzed specimens has been kept constant of 1000 mm in order to avoid any scale effect, and the two supporting faces have been restricted against displacements and also rotations, in order to simulate real conditions of laboratory. The mesh has been refined to a maximum element size of 10 mm (what corresponds to a ratio of Length/100), with a minimum of 3 elements in the tube wall-thickness, according to the calibration carried out by Albareda [19]; less than 3 partitions when using solid elements is not enough to simulate the nonlinear behavior of a cylindrical shell (see Fig. 7).…”

Section: Geometry and Meshmentioning

confidence: 99%

Estudio numérico y comparativo del comportamiento de columnas tubulares mixtas con un pretensado inicial de uno de los componentes : aproximación experimental del comportamiento de secciones CFST pretensadas, sometidas a compresión cíclica

Milan

View full text Add to dashboard Cite

(English) The use of mixed structures of the most varied types and typologies, mainly in steel and concrete, have been increasingly used in the recent decades. The mechanical advantages of these structures in comparison with conventional reinforced concrete and steel structures working independently, allow to optimize the performance of both components. Within all the possibilities of composite structures, this investigation focuses on the study of composite columns of circular tubular steel profiles filled with concrete (CFST). CFSTs are increasingly used due to improved structural performance, especially under compression. This is basically due to the confinement effect provided by the pipe, which generally improves the ductility and strength of the concrete fill. Mainly, a series of issues derive from the construction process of these sections, such as, for example, the fact of loading the tube before concreting in preliminary construction stages causes a preloading effort that implies a different response from the section than expected. These problems must be considered in the design process and lead to unwanted preload effects in one of the two components derived from the process itself. A limited number of studies treat preloading as a design method in itself before being under service loads (active methods) to improve the capabilities of CFST sections. Therefore, the thesis begins by analyzing and comparing 4 different methodologies (2 passive versus 2 active preload methods) describing the potential benefits and consequences of them throughout the section; while sometimes a prestress ratio in a component can improve the overall mechanical response, sometimes it doesn't and even becomes detrimental. The relation of the confinement effect on the core and especially when activated reveals the degree of real improvement of the compressive response of the section in terms of ductility and resistance. Finally, for the method that has been considered most beneficial, a small experimental campaign was carried out so that there is a first approximation of the behavior of this type of preloaded section. (Español) El uso de estructuras mixtas de distintos tipos y tipologías, principalmente en acero-hormigón, ha experimentado un aumento creciente durante las últimas décadas. Las mejoras mecánicas que ofrecen estas estructuras en comparación con las estructuras de hormigón armado y acero convencionales, permite aprovechar de forma optimizada las características de los dos materiales. De entre las tipologías más habituales de estructuras mixtas, esta tesis se centra en el estudio de columnas mixtas de perfiles tubulares circulares de acero rellenados con hormigón (CFST). Los CFST se utilizan cada vez más gracias a su gran rendimiento mecánico, especialmente sometidos a compresión. Esto se debe básicamente al efecto de confinamiento proporcionado por el tubo exterior, que generalmente mejora la ductilidad y resistencia del relleno de hormigón. Del proceso constructivo de estas secciones, principalmente, derivan una serie de cuestiones significativas, como el hecho de cargar el tubo antes del hormigonado en etapas constructivas preliminares, efecto que provoca un esfuerzo de precarga que deriva en una respuesta de la sección diferente a la esperada. Estos problemas deben ser considerados en el proceso de diseño y acaban produciendo efectos de precarga no deseados en uno de los dos componentes derivados del propio proceso. Existen varios estudios que tratan la precarga como un método de diseño en sí mismo, aplicando dichas cargas antes de que la sección entre en servicio (métodos activos) para mejorar las capacidades de las secciones CFST. Por ello, esta investigación empieza analizando y comparando 4 metodologías diferentes (2 métodos de precarga pasivos y 2 métodos activos) describiendo los beneficios potenciales y las problemáticas de cada uno de ellos en toda la sección; mientras que a veces una pre-tensión en un componente puede mejorar la respuesta mecánica global, a veces se vuelve incluso perjudicial. La relación del efecto de confinamiento sobre el núcleo y, especialmente, saber en qué momento éste se activa, revela el grado de mejora real de la respuesta a compresión de la sección en términos de ductilidad y resistencia. Finalmente, se ha realizado una campaña experimental en base al método de precarga que se ha considerado el más eficiente para poder validar las hipótesis hechas durante la fase numérica.

show abstract

Efficiency of stiffening plates in fabricated concrete-filled tubes under monotonic compression

Cited by 8 publications

References 14 publications

Analysis of slab-column connections in CFT sections without continuity of the tube

Analysis of slab-column connections in CFT sections without continuity of the tube

08.46: Local buckling of thin‐walled tubes encased in concrete

Estudio numérico y comparativo del comportamiento de columnas tubulares mixtas con un pretensado inicial de uno de los componentes : aproximación experimental del comportamiento de secciones CFST pretensadas, sometidas a compresión cíclica

Contact Info

Product

Resources

About