PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Highway Design Training CoursePart IIByXudong Jia, Ph.D., PETimothy RomineDepartment of Civil EngineeringCalifornia State Polytechnic University, PomonaMarch 2002Profiles and Vertical Alignment Elements of Profiles and Vertical AlignmentsCalTrans Standards on Vertical AlignmentCalTrans Standards Used in the Training ProjectConformance Check of CalTrans StandardsHorizontal Alignment TangentSegmentSpiralCircularCurveA vertical alignment alignment consists of a series of grade line segments and circular curvesTangent line segments are easy to handle. However the circular curves areNot. They affect significantly the safety considerations of a highway project and require a smooth transition from tangent segments.Circular Curve in Horizontal Alignment )(0079.0)(12722ssfeVfeVRPIBCECRSuperelevation emax and eSuperelevation e is a cross slope to balance the centrifugal forceemax is the maximum superelevation rate given a certain highway type.It varies from one highway type to another. For Example, emax = 0.10 for freeways (Page 200-9)e is the superelevation rate used in the designe is determined based on emax and R(Page 200-9)What is a standard superelevation rate of freeways and expressways with a curve radius of 400 m?Superelevation emax and eWhat is a standard superelevation rate of freeways and expressways with a curve radius of 400 m? emax= 0.10 from Table 202.2 Page 200-9e = 0.09 from Table 202.2 Page 200-9 with R = 400 mMinimum Radius of Circular CurvemRfeVfeVRss36012.01.0100*0079.0)(0079.0)(1272minmax2max2minTable 203.2 HDM P200-16DesignSpeedRmin3040506070809010011012013040701001502002603204006009001200Given emax = 0.10 for freeways (Page 200-9)V = 100 km/hFs = 0.12 from Page 200-10Superelevation TransitionSuperelevation Transition should be at the two ends of a curveIt consists of crown runoff and superelevation runoff (See Page 200-12)The superelevation runoff has its two third on the tangent and one third on the curve.Superelevation TransitionSuperelevation TransitionSuperelevation Transition (Example)A 400-meter radius curve is followed by a reversing curve of a 500-meter radius in a 4-lane undivided freeway. The two curves are separated by a tangent line of 100 meters. Does the design conform with the design standards?400 m500 m60 m400 m500 m60 mABA Curve: emax = 0.10e = 0.09 given R = 400 m2/3 Runoff = 0.67 * 99 = 66.33 mB Curve: emax = 0.10e = 0.07 Given R = 500 m2/3 Runoff = 0.67 * 78 = 52.26 m100 m < 66.33 + 52.26 = 118.59 m No OK, What do we do now?Superelevation Transition (Solution)Superelevation Transition (Solution)If the alignment is designed for 2-lane highways in mountainous terrain, ramps, collector roads, frontage roads, what do we do?Modify the rate of change of cross slope ( 4% per 20 m)Stopping Sight Distance on Horizontal CurvesSSD on Horizontal Curves (Example)A horizontal curve with a radius of 400 meters is designed on a two-lane highway that has design speed of 110 km/h. If the highway is flat at the curve section, determine the minimum distance a large McDonald’s billboard can be placed from the center line of the inside lane of the curve, without reducing the required SSD. Assume PIEV time of 2.5 sec and a = 3.4 m/sec2SSD on Horizontal Curves (Solution)metermmsRRmmetersSSDSSDGgaVVtSSD21.14))9.213*40065.28cos(1(*400))65.28cos(1(9.213)081.94.3(*2541105.2*110*278.0)(254*278.022CalTrans Standards on Horizontal AlignmentsHorizontal Alignment should provide at least the minimum SSD for the chosen design speed at all points of the highwayCurves should be designed with their radius greater than Rmin. If Rmin cannot provided enough lateral clearance to an obstruction, Figure 201.6 governs.The Design Speed between successive curves should not more than 15 km/h due to alignment consistencyWhen  < 10°, minimum curve length = 240 mWhen  < 0.5°, no curve is neededCompound curves should be avoided. Rshorter = 2/3Rlarger when Rshorter  300 mLarger radius curve follows smaller radius curve on 2-lane highwayCalTrans Standards on Horizontal AlignmentsThe connecting tangent on reversing curves should be greater than 2/3 runoff of the first curve and 2/3 runoff of the second curve. If it is not possible, 4% per 20 m governs. A minimum of 120 m should be considered when feasible.Broken back curves are not desirable.Alignment at bridges:superelevation rate on bridge  10%Bridges should be out of 2/3 runoff of the curve at two ends.CalTrans Standards on Horizontal AlignmentsSuperelevation:3000 m radius curve, no superelevation is neededAxis of rotationCenterline on undivided highwaysLeft edge of ETW on ramps and f-f connectionscenterline on divided highways with medianwidth  20 mmedian edges oftraveled way on divided highways with median width > 20 mDesign Procedures of Horizontal Alignment1. Investigate and assess the characters of the project area2. Determine individual elements of alignmentCurve Design: R mincurve length and SuperelevationRunoff3. Arrange Tangent Segments and Curves4. Check Conformance to Design StandardsSight DistanceSuperelevationHorizontal Alignments for Training ProjectThe Training Project involves the design of five horizontal alignments:One for FreewayFour for RampsFreeway Horizontal Alignment DesignTwo below PIs are given in the training project for the training project:English PI #1 X = 2710.80 ft, Y = 2077.69 ftPI #2 X = 4295.19 ft, Y = 2573.65 ftorMetric PI #1 X = 826.25 m, Y = 633.28 mPI #2 X = 1309.17 m, Y = 784.45 mA and B control points in terms of direction must be considered so that the freeway horizontal alignment is consistent with alignments outside of the project.Live Demo on how to design the horizontal alignment through trial and error effortsFreeway Horizontal AlignmentRamps Horizontal Alignment DesignA diamond interchange is proposed for the training projectThree below basic elements should be designed for each ramp:Freeway-Ramp ConnectorRamp AlignmentRamp-Local Road ConnectorFreeway-Ramp Connector DesignFreeway-Ramp Connectors should be designed