Benny Kusuma

Experimental Behavior of Concrete Columns Confined by Welded Wire Fabric as Transverse Reinforcement under Axial Compression

This study examines the behavior of normal-strength concrete short columns confined by welded wire fabric (WWF) as transverse reinforcement under monotonically increasing concentric compression. The authors investigate the effects of volumetric ratio, spacing and lateral steel configuration, and distribution of longitudinal steel around the core perimeter or longitudinal reinforcement ratio on the uniaxial behavior of reinforced concrete columns. Tests were conducted on 22 short concrete columns reinforced with longitudinal steel and WWF or conventional ties under axial compression. The performance of columns laterally reinforced with WWF was compared with that of columns laterally reinforced with conventional ties. The findings show that WWF can be effective in confining the core concrete. Ductility increases of 130% and strength increases of at least 17% were found when compared with the corresponding specimens with conventional ties. The ductility of confined concrete columns improved with an increase of longitudinal reinforcement and decrease of transverse reinforcement spacing. Welded grids reduced the congestion of reinforcement and improved concrete quality in the members.

Spline Nonparametric Regression Analysis of Stress-Strain Curve of Confined Concrete

Note from the Editor: The ability to forecast maximum water depth during maximum discharge of a design flood is very important in designing flood protection scheme along the river reach. This paper explains the use of ISIS Flow, a one-dimensional hydrodinamic computer modelling for river flood forecasting. The computer simulations produced detailed information from each node including the maximum water depth during maximum discharge, thus it can be expected that an economical flood protection structure can be produced.Variable Message Sign (VMS) is especially recommended for congested flow conditions. The aim of this study is to investigate how drivers in a large city in a developing country with many specific geometric and traffic conditions and also specific driver behaviour, use VMS in aid of choosing route for their inter-city trips. Furthermore, to explore the impact of the use of the information on increasing traffic performance measures. A case study was carried out in Bandung, Indonesia. Microscopic traffic simulations were used in this study to evaluate traffic performance measures. The results of the evaluation found that VMS has insignificant impact on drivers’ route choice behaviour. The results indicated that drivers in Bandung rely much on their experience of traffic conditions commonly occur in the city and demonstrated that VMS has no significant impact to increase traffic performance, but has better impact on the roads with higher number of alternative roads.Due to enormous uncertainties in confinement models associated with the maximum compressive strength and ductility of concrete confined by rectilinear ties, the implementation of spline nonparametric regression analysis is proposed herein as an alternative approach. The statistical evaluation is carried out based on 128 large-scale column specimens of either normalor high-strength concrete tested under uniaxial compression. The main advantage of this kind of analysis is that it can be applied when the trend of relation between predictor and response variables are not obvious. The error in the analysis can, therefore, be minimized so that it does not depend on the assumption of a particular shape of the curve. This provides higher flexibility in the application. The results of the statistical analysis indicates that the stress-strain curves of confined concrete obtained from the spline nonparametric regression analysis proves to be in good agreement with the experimental curves available in literatures.