Structural efficiency of hollow reinforced concrete beams subjected to partial uniformly distributed loading

Reinforced concrete (RC) beams containing a longitudinal cavity have become an innovative development and advantage for economic purposes of light-weight members without largely affecting their resistance against the applied loads. This type of openings can also be used for maintenance purposes and usage space of communication lines, pipelines, etc. RC beams are primarily loaded in the plane of the members, which are two-dimensional in a plane stress state and the dominant structural behaviours include bending, shear, or combination of both. In the present study, six numerical models of RC beams with and without openings were simulated by using commercial finite element software ANSYS to evaluate the structural behaviours of those beam models under the partial uniformly distributed load. Different parameters were assessed, including opening dimensions and shear reinforcement ratios. The obtained numerical results were analysed and verified and were found very close to those obtained from the experimental investigations in the literature. The increase of shear reinforcement ratio could enhance the flexural and shear capacities of the RC beams, and the results also showed that some models sustained flexural failure while the others sustained failure of combined bending and shear

Numerical simulations on the flexural responses of rubberised concrete

The increase in world population has led to a significant increase in the numbers of cars and used tyres. These tyres must be disposed of on an ongoing basis as a result of their consumption or deterioration. This can result in negative effects on the environment that must be preserved, especially from those materials, i.e., these waste materials are difficult to dispose of without special treatments. Hence, extensive experimental investigations and numerical simulations need to be conducted to use and recycle these wastes by exploring the possibility of using them as alternative ingredients in construction materials. For example, waste rubber pieces can be used as one of the main components of concrete. In this study, the main aim was to numerically simulate the flexural behaviours of rubberised concrete under the influence of an applied vertical loading with different contents of added rubbers by using the commercial finite element software ANSYS. The obtained numerical results were compared with the experimental results of a previous study and showed a good agreement with the deflections and moduli of rupture, with the variances from 2–7% in the deflections. However, the differences in the moduli of rupture varied between 5% and 9%. Finally, the statistical analyses indicated that these numerical mean values and standard deviations were acceptable and were very close to the experimental values

Numerical Simulations on the Flexural Behaviours of Reinforced Concrete Girders Strengthened with Bolts

Precast reinforced concrete (RC) girders with dapped ends are used in order to reduce the overall depths of concrete floors and bridge decking and meet architectural requirements. The structural requirements by reducing the depths of these girders result in stress concentrations within the recessed zones. Thus, girders with dapped ends require special details for the strengthening systems. The use of open transverse holes in RC sections is for the passage of various service lines such as telecommunication cables, gas lines, water pipes, electricity cables, etc. The behaviours of RC girders with dapped ends and openings strengthened by bolts subjected to two vertical concentrated loads were numerically simulated by utilising commercial finite element software ANSYS. The numerical results from the simulated models were identical and compatible with those experimental results stated in literature. The validation of the numerical results with those experimental ones was based on the statistical analysis by including the calculations of the correlation coefficients, arithmetic means, and standard deviations for all the simulated girder models in terms of loads and deflections. The obtained numerical results showed that an increase in the compressive strength of concrete by 20% would cause an increase in the loading resistance of the models by 13% and a decrease in the deflection by 21%, respectively. Also, it was indicated that the type of section, i.e., the change of the section from solid to open (with transverse openings), would decrease the resistance of the section by 8–16% and increase the deflections by 15–20%. Similarly, an increase in the number of holes would result in the decreases in the load resistance by up to 6% and the increases in the deflections by up to 24% under the same applied loads. Strengthening openings using vertical bolts has an important role in enhancing the resistance of the models by 8–20% and decreasing the deflections by 20–30%. The failure patterns were hybrid, e.g., flexure and shear, and identical with the experimental ones. Finally, the effect of using the cylindrical compressive strength of concrete as a mechanical parameter on the structural behaviours of the simulated models was investigated, which could improve the resistance loading and decrease the deflections of the models

Nonlinear Simulation Analysis of Tapered Reinforced Concrete Column (Solid and Hollow) Behavior Under Axial Load

Tapered columns are a type of column that is used for different purposes, including architectural purposes or structural needs to take into account the changes that occur to moments along with the height of the column. For example, in highway bridges, tapered columns are used to reduce the number of moments transmitted to the base of the columns and from there to the foundation. This research studied the analysis of short reinforced concrete columns with variable cross-sections along the column in a linear manner by using the ANSYS V.15 software package. The variables that were studied included the type of section, solid or hollow, the ratio of longitudinal and transverse reinforcement, the ratio of the hollowness, and the comparison of numerical results with those obtained from the previous study. The results we obtained from the simulation of the numerical analysis of the models showed a very good agreement with the results of the experimental studies for them. This agreement can also be observed through statistical analysis using the arithmetic mean and standard deviation when compared. Thus, the proposed model by numerical analysis and hypotheses is suitable for formulating the behavior of these reinforced concrete tapered column models under the effect of axially applied load and other variables. The behavior of column models is based on applied loads, load-displacement curves, crack patterns, and failure modes. The results showed that increasing the ratio of longitudinal and transverse reinforcement increases the resistance of the R.C. column models and the ductility index with a decrease in the corresponding lateral displacement. This behavior is observed when changing the section from hollow to solid. Finally cracks pattern is represented in the concrete crushing and concrete spalling out of some parts at the end of the tapered and diagonal cracks in different places, especially at the end of the tapered. Validerad;2021;Nivå 2;2021-10-20 (alebob);Funder: Mustansiriyah University</p

Nonlinear Simulation Analysis of Mechanical Behaviour of Rubberized Concrete

Validerad;2022;Nivå 2;2022-02-21 (joosat)</p