Ellipse offset curves in the formation of turbo-roundabouts

Journal Title: Roads and Bridges - Drogi i Mosty - Year 2015, Vol 14, Issue 3

Abstract

Various curves are used for shaping the geometry of roads and a curve applied the most often is the circular arc. Clothoid, spiral, ellipse, sets of curves shaped with polynomial functions and other similar curves are also worth mentioning. The road axis is usually set during practical realization of the curves in the terrain. The external edges are determined by measuring the width of the carriageway along the normal line to this axis. That is how two offset curves, which usually are of different type, are created. If the road axis is a circular arc with a radius R, then by displacing the width of the carriageway s along the radius of the circle, the circular arcs with radii R-s and R+s are also created, assuming that s is constant. While shaping turbo-roundabouts different curves are suggested, e.g. an ellipse. In case of its application, by displacing the width of the carriageway from its axis, the curves that fulfill the conditions of ellipses' equations are not created, but only the curves similar to them. The question is how large are the deviations? Are they important in practical realization? The analyses included in this article give answers to these questions.

Authors and Affiliations

Ryszard J. Grabowski

Keywords

Related Articles

The influence of rail-vehicles’ properties on dynamic response of a beam bridge

The study is focused on assessment of the influence of the basic properties of rail-vehicles on the dynamic response of the beam bridge in a wide range of a service velocity of the cyclic moving load. The analysis relate...

European Ecological Network Nature 2000 and development of the transportation routes

The paper characterizes the problem of preservation of natural environment in connection with extension of transportation road systems. The European Union program concerning the European Ecological Network Nature 2000 is...

Impact of reinforcement layer material and thickness on deflections measured in the static and dynamic plate load tests

The bearing capacity and compaction values obtained in the plate load tests (the latter determined indirectly) often depend on the used test method: static - using static load test apparatus (VSS) or dynamic - using ligh...

Prediction of the number of trips attracted to the city

Traffic in the city is generated not only by its citizens, but also by the other persons, that visit the city for obligatory and facultative purposes. The author's research results show that these persons generate a sign...

Reinforced concrete viaduct from beginning of the 20th century – microstructure analysis of 100 years old concrete

In the paper the history of a viaduct from Railway Warsaw - Kalisz and its present condition is described. The parabolic vaulted viaduct that was built for the Railway Warsaw - Kalisz, is probably one of two oldest concr...

Download PDF file
  • EP ID EP76265
  • DOI 10.7409/rabdim.015.013
  • Views 114
  • Downloads 0

How To Cite

Ryszard J. Grabowski (2015). Ellipse offset curves in the formation of turbo-roundabouts. Roads and Bridges - Drogi i Mosty, 14(3), 193-202. https://europub.co.uk/articles/-A-76265