Papers by Keyword: Concrete Columns

Abstract: Design of concrete columns subjected to axial force and uniaxial bending moment from the point of view of prepared prEN1992-1-1/2021. A comparison by interaction diagrams for concrete strength classes C30/37 and C90/105 for symmetrically and asymmetrically reinforced cross-section and for symmetrical cross-sections only to one axis, respectively.

Abstract: In the paper the main results of numerical study presented in Gambarelli et al. [1] on concrete elements confined by carbon fiber reinforced polymer (CFRP), are overviewed. Furthermore, preliminary results of numerical simulations performed at mesoscale are presented.The numerical study is based on a extensively experimental campaign conducted by Wang and Wu [2] on small CFRP-confined concrete columns loaded in uni-axial compression. The specimens are characterized by constant size but different cross-section corner radius (from square to circular cross section). The experimental results clearly demonstrate that CFRP confinement is much less effective in square then in circular cross-section.Several numerical models have been performed at macro-scale and meso-scale to confirm the predictability of the used numerical approach, based on the microplane constitutive law for concrete [3]. In the finite element model carbon fibers (truss FE) are embedded into matrix (solid 3D FE). The same as for concrete, the constitutive law for matrix is also based on the microplane model.It is demonstrated that the numerical model is able to predict behavior of confined concrete columns from the experimental investigations. Therefore, the results of the study confirm the predictability of the used numerical approach.

Abstract: Chemical bonded reinforcement is widely used in structural rehabilitation, retrofitting and strengthening. Pull-out test of bonded anchor in concrete block was widely used in research but it cannot reflect the practical behavior of bonded reinforcement in structure. 6 RC columns in which longitudinal reinforcements overlap with chemical bonding technique were tested under eccentric compressive loads. The failures of some columns were caused by weak bonding capacity while most were caused by yielding of steel. The failure mode depends on the overlap length of bonded reinforcement. The ultimate load, deflection curve and cracking situation of tested columns were similar with usual RC columns, but the values of rigidity were influenced by bonding strength and anti-sliding stiffness of anchorage. The mechanical properties of concrete column with chemical bonded reinforcement were also influenced by bonding construction quality.

Abstract: This paper presents experimental results of a series of large-scale reinforced concrete circular and square columns tested under lateral cyclic displacement excursions while simultaneously subjected to constant axial load. All the specimens contained only minimal transverse steel and were then retrofitted with CFRP or GFRP jackets except control specimens. The measured hysteretic loops of the moment vs. curvature and shear vs. deflection relationships are reported for each specimen. It was observed that both CFRP and GFRP wrapping could provide effective confinement and significantly improve the seismic performance of columns. The effectiveness of FRP in enhancing column ductility relates more closely to its tensile strength than stiffness, thus the application of GFRP confinement to concrete columns is promoted due to obtainability and economical concern.

Abstract: Twelve PVC tubed short concrete columns and four columns without PVC tube confined were tested under axial load to investigate mechanical properties of axially loaded PVC tubed short concrete columns . The principal influencing factors such as concrete strength, loading condition and ratio of height to diameter were studied. Test results indicated that strength and deformation performance of core concrete increased as a result of the confinement of PVC tube. The PVC tube confinement effect on concrete will decrease with an increase in strength of concrete. Load- carrying capacity and deformation of short composite columns with different loading condition made some difference. As the ratio of height to diameter increases, load- carrying capacity and plasticity of short composite columns decreased gradually.