Effect Of Skew Angle Research Articles

Effect of Skew Angle on the Dynamic Response of a Reinforced Concrete Bridge under Blast Loading

Accidental explosions and subversive blasts are on rise. The recent devastating Beirut explosion witnesses this fact. Performance of the structures such as bridges in cities and strategic boarder areas is of paramount importance. With this concern the effect of skew angle on the performance of a single span reinforced concrete (RC) bridge deck supported on three symmetrically placed RC girders under blast loading generated by1000kgTNT charge located above and below the mid-section of the central girder at a standoff distance of 0.5 m has been investigated using ABAQUS/CAE. Analyses have been performed at different skew angles i.e. 0º, 10º, 20º, 30º, 40º, and 50º. Several empirical relations from the literature have been used to estimate the blast parameters such as peak overpressure, positive phase duration, the arrival time of blast wave, and decay coefficient. Blast pressure P(t), has been modeled using modified Friedlander’s equation. Distributions of damages have been evaluated with a mesh size of 300 mm using concrete damage plasticity (CDP) model. Maximum displacements have been computed and are compared with those obtained from the provisions of AASHTO: Load Resistance and Factor Design (LRFD) - Bridge Design Specifications (2014). It has been found that the midspan displacement and the stresses of the deck increase for 10º skew angle but decrease for subsequent increase in skew angle for the explosive charge loaded above the mid-section of the central girder. However, tensile as well as compressive damages in girders increase with increase of skew angle irrespective of the location of the blast. Side girders suffer more damage with increase in skew angle than uniform damage for ‘under the deck’ location of explosive charge.

Effect of Skew Angles on Longitudinal Girder and Deck Slab of Prestressed Concrete T Beam Girder Bridges

Abstract: The present paper shows the effects of varying skew angles on pre-stressed concrete (PSC) bridges using finite elemental method. Studies are carried out on PSC bridge decks to understand the influence of skew angle and loading on behaviour of bridges. The results of skewed bridges are compared with straight bridges for IRC Class AA Tracked loading. Also, a comparative analysis of the response of skewed PSC Slab Bridge decks with that of equivalent straight bridge decks is made. The variation of maximum longitudinal bending moment (BM), maximum transverse moment, maximum torsional moment, and maximum longitudinal stresses deflection at obtuse corner, acute corner with skew angles are studied for bridge deck. It is found that Live load longitudinal bending moments decreases with an increase in skew angle, whereas a maximum transverse moment and maximum torsional moment increases with an increase in skew angle. The benefit of pre-stressing is reflected in considerable decrease in the longitudinal bending moment, transverse moment and longitudinal stresses. The models are analysed with the help of software CSI-Bridge V 20 Version. Keywords: Skew angle effect, Longitudinal moment, Transverse moment, CSI- Bridge software, Deck slab, Finite element method.

Effect of Skew Angle on Bridge Superstructures

In this paper, the effect of skew angle on reinforced concrete skew bridge decks is presented by using the grillage analogy. The actual deck system of the bridge is represented by an equivalent grillage of longitudinal and transverse beams. A span 26m of simply supported bridge deck is taken as the case study to obtain the values of the bending moment' s distribution versus span length for the one type of skewness and the results are compared against the moments of the right deck span of the bridge. The analysis results were based (BS5400) dead and live loads using Structural Analysis program (SAP2000). The analysis provided useful information about the variation of moments and shear forces with respect to change in skewness. It is concluded that in skew bridge deck, the bending moment is decreased, but torsional moments and shear forces are increased by increasing the skew angle. It is noticed that the maximum bending moment at skew angle 55o, by 76% in comparison with zero skew angle. On the other hand the maximum torsional moment increases for the same skew angle (55o) more than five times than with zero skew angles.

Effect of Skew Angle of Holes on the Thermal Fatigue Behavior of a Ni-based Single Crystal Superalloy

In the present work, holes of various skew angles were electrochemically machined in the middle of the plate specimens in a Ni-based single crystal superalloy and crack initiation and propagation around holes during thermal fatigue cycles (20–1100 °C) were investigated. It was demonstrated that the skew angles had a significant effect on the initiation and propagation of thermal fatigue cracks. During thermal fatigue process, stress concentration occurred at the edge of the holes. As for skew angles, the maximum stress concentration appeared at the acute side of holes. The maximum stress concentration resulted in plastic deformation at the acute side of the 30° hole, driving the thermal fatigue cracks to initiate after 220 cycles and propagate along \([0\bar{1}1]\) direction. However, the stresses concentrated at the edge of 90° or 60° holes were not large enough to initiate cracks even after 580 thermal cycles. This work will help to understand the local deformation behavior in the vicinity of cooling holes with various skew angles and have serious design implications for turbine blades.

Effects of Skew Angle of Rotor in Squirrel-Cage Induction Motor on Torque and Loss Characteristics

We have developed a 3-D finite-element mesh modification method for skewed motors with an auto-mesh generator. Meshes modified by the auto-mesh generator are broken as enlarging the skew angel. In order to solve this problem, we have improved the modification method by solving Laplace equation. In this paper, characteristics of the skewed squirrel-cage induction motor are analyzed by changing the rotor skew angle using the meshes created by the improved mesh modification method.

Effect of Skew Angle on Distribution of Bending Moments in Bridge Slabs

Effect of Skew Angle on Distribution of Bending Moments in Bridge Slabs

Effect of Skew Angle on Rigid-Frame Reactions

Effect of Skew Angle on Rigid-Frame Reactions