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Roundabouts are a superior solution to traffic operation issues at intersections with complex geometry, such as skewed and offset approaches where there are property constraints or where realigning approaches is costly. Although roundabouts with offset, skewed approaches are unavoidable, the current design standards are typically established based on standard roundabouts having radial approach alignments and perpendicular approaches. This work aimed to (1) examine the geometric characteristics of roundabouts with offset or skewed approaches or both, (2) establish the relationships of the design parameters with the approach offset and angle, (3) develop geometric optimization models, and (4) recommend geometric design guidelines for inscribed circle radius, entry curve radius, and exit curve radius. The approach or intersection angle ranges are also recommended for single-lane and two-lane roundabouts under urban and rural conditions. Design graphs and tables of the minimum required radii were developed. They not only help highway designers and engineers to select the appropriate parameters and reduce trial-and-error efforts during design, but also offer a guide to property needs during the planning stage. [ABSTRACT FROM AUTHOR]

Bridges are common and important constructions to overcome different obstacles in any transportation network. Variations in bridge types include variation in span length, statical system, construction material, construction methods and sustained loads. Choosing the suitable statical system is affected with several factors such as construction time, availability of materials, available budget, contractors' background and one of the most important factors is the layout of the road network or obstacles outline beneath the bridge. Skew bridges result from inclined intersection between bridge axis and the below road or water stream. The famous problems that result from this inclination are distribution of loads among the main girders and variation in bearings' reactions. Stiffness of cross girders especially near the skew edge affects noticeably the distribution of loads in main girders. In this paper, analysis of medium span skew RC girder bridge deck will be proposed using different skew angles (α) measured from horizontal axis that are 20̊, 30̊, 40̊ and 50̊ and different cross girder patterns. Analysis will be performed using grillage model in FEM software package. Analysis includes different skew angles, different cross girder patterns and different distributed gravity load patterns. The observed outputs in the analysis are reactions at bearings and bending moment values in main girders. In this paper, effect of skew angles and different cross girders patterns on reactions at bearings will be introduced. The effect of these variables on main girders BM values will be discussed in extended paper work. [ABSTRACT FROM AUTHOR]

Holes of various skew angles were electrochemically machined (ECM) in the middle of the plate specimens in a Ni-base single crystal (SX) superalloy. The surface strain fields around the holes during tensile test at room temperature were in-situ observed by an ARAMIS – optical 3D deformation analysis system based on the digital image correlation (DIC) technique. It was demonstrated that both the yield stress and the tensile elongation increased with the increase of the skew angles from 30° to 90°. Strain concentrated at the acute side of the skew holes. The results were analyzed based on the crystallographic structure of specimens and the slip traces observed on fracture surfaces. [ABSTRACT FROM AUTHOR]

We performed a free vibration analysis of skew composite laminates with or without cutout based on the high-order shear deformation plate theory (HSDT). The effects of skew angles and ply orientations on the natural frequencies for various boundary conditions are studied using a nonlinear high-order finite element program developed for this study. The numerical results are in good agreement with those reported by other investigators for simple test cases, and the new results reported in this paper show the interactions between the skew angle, layup sequence and cutout size on the free vibration of the laminate. The findings highlight the importance of skew angles when analyzing laminated composite skew plates with cutout or without cutout. [ABSTRACT FROM AUTHOR]