Effect on support reactions of T-beam skew bridge decks

Trilok Gupta and Anurag Misra

T-beam Bridge is a common choice among the designers for small and medium span bridges. In order to cater to greater speed and more safety of present day traffic, the modern highways are to be straight as far as possible. This requirement, along with other requirements for fixing alignment of the bridges, is mainly responsible for provision of increasing number of skew bridges. The presence of skew in a bridge makes the analysis and design of bridge decks intricate. For the T-beam bridges with small skew angle, it is frequently considered safe to ignore the angle of skew and analyze the bridge as a right bridge with a span equal to the skew span. However, T-beam bridges with large angle of skew can have a considerable effect on the behavior of the bridge especially in the short to medium range of spans. In this paper a study on the behavior of T-beam skew bridges with respect to support reactions under standard IRC-70R wheeled loading is presented and the study was based on the analytical modeling of T-beam bridges by Grillage Analogy method. Effects of support reactions for different spans have been studied. The analysis provides the useful information about the variation of support reactions with respect to change in skew. The negative reactions were observed with increase in the span and skew angles. It was found that in skew T-beams bridges, the high positive and negative reactions develop close to each other. Negative reactions were very less in the 8m right span and introduced at an angle of 500 and onwards, while for 16m right span it was introduced an angle of 300. In 24m and 32m right spans the negative reactions develops at smaller skew angles (i.e. 200 and onwards).

Reichardt’s dye as Optochemical Sensor materials detected polar gas

Fang Han, Takanori Inoue, Yoshiaki Kurauchi and Kazuya Ohga

A sensor that can detect polar gases was developed based on Reichardt's solvatochromic dye. The Reichardt's dye was incorporated into PVP (polyvinyl pryrolidone) and then was fabricated into sensing films. The sensing film can produce strong, fast and reversibly signals when it exposed to polar gases, with response time in the range of 5-20 seconds. High-resolution micrographs of the sensing film in different polar gases were obtained by using a digital camera. Using the high-resolution micrographs, a concentration as low as 0.05% (v/v) methanol gas can be detected. This detection is completely reversible under any vapor concentrations.

Design and calibration of a bi-axial extended octagonal ring transducer system for the measurement of tractor-implement forces

Khan J., R. J. Godwin, J. Kilgour and B. S. Blackmore

A bi-axial extended octagonal ring (EOR) transducer system for the measurement of tractor-implement forces was designed for a category II and III MB Trac 1300 tractor. The EOR transducers and a gauged top link were calibrated and the Sensitivity, Cross-Sensitivity, Hysteresis, Linearity and Repeatability were found. The system was tested for 80kN applied coincident load and 60kN perpendicular load. No lateral forces or moment in the plane of the two forces was considered. The results of the calibration tests of the system showed its workability. The system could best be used for the measurement of draught (horizontal) and vertical forces where heavy implements are attached with the tractor.

Denoising of computer tomography images using curvelet transform

R. Sivakumar

A special member of the emerging family of multiscale geometric transforms is the curvelet transform which was developed in the last few years in an attempt to overcome inherent limitations of traditional multistage representations such as wavelets.  The Computer Tomography images were denoised using both wavelet and curvelet transform and results are presented in this paper. It has been found that the cuvelet transform outperforms the wavelet transform in terms of signal noise ratio.

Buckling load of a beam-column for different end conditions using multi-segment integration technique

Goutam Saha and Sajeda Banu

A method of identifying the buckling load of a beam-column is presented based on a technique named ‘Multi-segment Integration technique’. This method has been applied to a number of problems to ascertain its soundness and accuracy. We consider a boundary-value problem for the beam-column equation, in which the boundary conditions mean that i) it is hinged at both ends; ii) it is fixed at both ends; and iii) it is fixed at one end and hinged at the other end. The results obtained by Finite Difference method are compared in order to determine the efficiency of this method.