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Horizontal Curves- Superelevation-Vertical Curves
Dr. Ahmed A. Khalil4th year Civil
weeks 10- 11- 12
1- Simple Curve2- Compound Curve3- Reverse Curves4- Superelevation required for such curves5- Spiral curves as a means of introducing thesuperelevation on a gradual and uniform basis.
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superelevation on a gradual and uniform basis.6- Vertical Curves
- A simple curve has a constant radius throughout.- The degree of curvature generally is measured by thecentral angle subtended by a 100-ft-long chord
11-- Simple CurveSimple Curve
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A compound curve comprises two or more simplecurves.Each successive curve having a common tangent withthe preceding curve.
Compound Curve & Reverse CurvesCompound Curve & Reverse Curves
Compound curves should be avoided, but theymay be used where excessive excavation or fixed
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may be used where excessive excavation or fixedobjects that must be cleared justify or require such acurve
A reverse curve is a combination of two simple curveswith centers on opposite sides of a common tangent
Reverse curveReverse curve
Reverse curves are acceptable in slow-speed passingand yard tracks but should never be used in main line.
A short tangent, at least 100 ft long, but preferably
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A short tangent, at least 100 ft long, but preferablymore, should be placed between curves of oppositedirection in main line
قیم العجلة الجانبیة المؤثرة علي راحة الركابقیم العجلة الجانبیة المؤثرة علي راحة الركاب****
تعتمد راحة الراكب علي قیمة العجلة الجانبیة وفترة تأثیرھا والتردد المحتمل ١.٥عند ٢ث /م١فقد وجد أن عجلة تساوي .لجسم االنسان واتجاه العجلة
٣ولفترة ، ساعات ونصف في االتجاه الرأسي٥ھرتز یمكن تحملھا لفترة والحد األقصي المسموح بھ للعجلة الجانبیة .ساعات ونصف في االتجاه األفقي
٢ث /م١المؤثرة علي الراكب ھو
ولراحة الراكب فإن العجلة الجانبیة المتولدة یجب أال تتعدي ثلثي العجلة التي
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ولراحة الراكب فإن العجلة الجانبیة المتولدة یجب أال تتعدي ثلثي العجلة التي .یتحملھا الراكب
:وتعطي القیمة الدنیا إلرتفاع الظھر عن البطن بالمعادلة
Desirable length of transition between reverse curvesDesirable length of transition between reverse curves
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Curvature of Compound curveCurvature of Compound curve
Curvature of Reverse curveCurvature of Reverse curve
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Curvature of Reverse curveCurvature of Reverse curve