Axial Compression Behaviors of the Steel Tube Confined Reinforced Concrete Columns with Binding Bars

An experimental study on the steel tube confined reinforced concrete (STCRC) column with binding bars under axial compression is conducted. The bearing capacity and failure modes are obtained. It can be known that the axial deformation of concrete occurred under compression. The core concrete is wrapped and constrained by the steel tube wall, and the steel tube wall is constrained by binding bars locally, so the local buckling shape of the wall between the binding bars is like wave shape. The 3D finite element model is also developed to analyze the behavior of this type of column under axial compression. Good agreement is shown between the test and predicted results in terms of the load-deformation curves and ultimate strength. The parametric studies indicate that the spacing of binding bars, diameter of longitudinal bars, concrete strength, thickness of the steel tube wall, and section dimension of the column generate different influence on the mechanical properties and bearing capacity. The diameter of longitudinal bars, concrete strength, and section dimension of the column have a great effect on the ultimate bearing capacity. The numerical results also show that the spacing of binding bars has little effect on the ultimate bearing capacity. The larger thickness of the steel tube wall leads to adverse effect on the specimen performance. Finally, the theoretical calculation is carried out, and the result is good.

Investigation of Parameters Affecting the Equivalent Yield Curvature of Reinforced Concrete Columns

In this study, the response quantities affecting the equivalent yield curvature, which is important in the deformation-based seismic design and assessment of structural systems, are investigated for reinforced concrete columns with a square cross-section. In this context, the equivalent yield curvatures were determined by conducting moment–curvature analyses on various column models, in which the axial load level, cross-section dimension, longitudinal reinforcement ratio, and concrete compression strength were changed parametrically, and the independent and/or combined effects of the relevant parameters were discussed. Depending on the axial load levels of P/Agfc′ < 0.3, P/Agfc′ = 0.3, and P/Agfc′ > 0.3 for the considered columns, the yielding of reinforcement, yielding of reinforcement and/or concrete crushing, and concrete crushing governed the yield conditions, respectively. It can be noted that the cross-section dimension and axial load level became the primary parameters. Even though the independent effects with regard to particular parameters remained at minimal levels, the combined effects of them with the axial load became important in terms of the equivalent yield curvature.

Three-dimensional mixed convection heat transfer in a partially heated ventilated cavity

The 3-D mixed convective heat transfer inside a ventilated cavity partially heated is studied numerically by using control volume method. The heating square portion similar to the integrated electronic devices is placed on the left vertical wall of the enclosure. The right vertical wall is maintained at ambient temperature and all other walls are adiabatic. The results are presented in terms of flow structures, temperature distribution, and global average Nusselt number for various combinations of thermal controlling parameters, namely, the Richardson number (0 ? Ri ? 10), the Reynolds number (10 ? Ri ? 200), the heating section dimension (0. ? ? ? 0.7), and the relative height of the openings B = h/L = 1/8. It is found that for the low Reynolds number the heat transfer process is carried out only by conduction. On the other hand, the highest thermal performance is achieved by reducing the heating section dimension.

A Statistical Factor Asset Pricing Model Versus the 4-Factor Model

This research aims to compare the performance of a statistical factor asset pricing model with the Fama-French-Carhart 4-factor model. We perform a Principal Component Analysis (PCA) to extract latent risk factors using data of stocks listed on B3 from 2001 to 2015. We test the abilities of the two models to explain assets' returns both in the time-series and in the cross-section dimension. We found that the statistical factor models generates statistically significant abnormal returns in the time-series analysis while the 4-factor model does not. In the cross section dimension, neither model generates significant abnormal returns but they also are not able to generate positive risk premia. Similar results are found if we consider different sets of time and assets. Therefore, although the 4-factor model performs slightly better in the set of tests, neither of the models can be considered fully adequate to explain expected returns of assets in the Brazilian stock market.

Intensity increase in metal removal at vibration treatment based on use of “slot” effect in working chamber

The results of the investigations on metal removal intensity increase during the vibration treatment on the basis of the “slot” effect use in a working chamber are presented. The investigation results presented show that with the decrease of a section dimension in the working chamber metal removal increases and surface roughness is getting better.

Experimental Investigation of Concrete Confinement with Textile Reinforced Concrete

Mechanical property and constraint mechanism of concrete cylinders confined by TRC under uniaxial compression is analyzed. 24 concrete cylinders confined by TRC and 8 unconfined concrete cylinders are loaded under uniaxial compression to investigate the performance based on textile ratio, section dimension and strength of concrete. Based on the test results, stress process and failure mechanism of strengthened members is studied, stress-strain relationship of strengthened members is researched, effect of ratio of textile reinforcement, section dimension and concrete strength on ultimate strength of strengthened members is also evaluated. The results show strengthened members showed increasing in strength and deformation. Strengthened members showed drum-shaped shear damage. With the increasing of textile ratio, the confining effect of TRC on the concrete increases. With the increasing of section dimension, the confining effect of TRC on the concrete decreases. The confining effect of TRC on low strength concrete is stronger.

MAPPING ASPERITIES ALONG THE SAGAING FAULT ZONE, MYANMAR USING b-VALUE ANOMALIES

In this study, the b-values of frequency-magnitude earthquake distributions were mapped spatially along the sagaing fault zone (SFZ), central Myanmar. Three sub-datasets of the complete earthquake catalogue were tested in order to ensure the applied assumption. Using the present-day dataset (1980–2010), two areas of low b-values, which are prospective potential earthquake sources, were identified at the Naypyidaw-Mandalay and southwestern part of Myitkyina in the central and northern part of the SFZ, respectively. To assess the possible earthquake magnitudes, the b-values were mapped in the cross-section dimension along the SFZ. The obtained areas of low b-values, referred to as the fault asperity regions, conformed to those illustrated in the surface map. The asperity's sizes, examined from specific low b-values of ≤ 0.65 and ≤ 0.060 were quantitatively estimated and empirically converted to the potential earthquake magnitudes. This analysis revealed three prospective areas surrounding the Myitkyina regions capable of generating earthquakes in the future with a possible magnitude of 8.6 Richter. The contribution of effective mitigation plans are, therefore, urgently needed for Myanmar and the adjacent area.