CHAPTER 2 GEOMETRIC DESIGN CRITERIA - TN.gov
CHAPTER 2GEOMETRICDESIGN CRITERIA
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:CHAPTER 2 GEOMETRIC DESIGN CRITERIATable of ContentsINTRODUCTION . vSECTION 1 – CONTROLLING GEOMETRIC DESIGN CRITERIA . 12-100.00CONTROLLING CRITERIA FOR DESIGN . 12-101.00HORIZONTAL DESIGN . 12-101.01HORIZONTAL CURVE RADIUS AND SUPERELEVATION RATES. 12-101.02TRAVEL, THROUGH, AND TURN LANE WIDTHS . 32-101.03SHOULDER WIDTHS. 32-101.04CROSS SLOPES . 42-102.00VERTICAL DESIGN. 42-102.01VERTICAL GRADES . 52-102.02STOPPING SIGHT DISTANCE . 52-102.03STOPPING SIGHT DISTANCE ON HORIZONTAL AND VERTICALINTERSECTIONS . 52-102.04STOPPING SIGHT DISTANCE ON HORIZONTAL AND VERTICALCURVES . 52-102.05VERTICAL CLEARANCES FOR BRIDGES. 72-103.00DESIGN SPEED . 82-104.00DESIGN LOADING STRUCTURAL CAPACITY . 82-105.00DESIGN EXCEPTION REQUESTS . 8SECTION 2 – NON-CONTROLLING GEOMETRIC DESIGN CRITERIA .182-200.00NON-CONTROLLING GEOMETRIC DESIGN CRITERIA.182-200.01PASSING SIGHT DISTANCE .182-200.02VERTICAL CURVES .182-200.03ROADSIDE SLOPE DEVELOPMENT .192-200.04CLEAR ZONE .202-200.05DESIGN VEHICLE .212-200.06MULTIMODAL FACILITIES .222-201.00DESIGN WAIVER REQUESTS .22SECTION 3 – INTERSECTIONS .292-i
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:2-300.00INTERSECTIONS .292-301.00LANE DROP AFTER INTERSECTION .292-302.00TURNING LANES AT INTERSECTIONS .322-303.00J-TURN INTERSECTIONS .352-304.00INTERSECTIONS LOCATED NEAR THE LIMITS OF CONSTRUCTION .36SECTION 4 – INTERCHANGES .372-400.00INTERCHANGES .372-400.01INTERCHANGE RAMP DESIGN .372-400.02TWO-LANE ENTRANCE RAMPS ON FREEWAYS AND EXPRESSWAYS .382-400.03ACCESS CONTROL AT INTERCHANGE RAMPS .39SECTION 5 – MEDIANS .402-500.00MEDIANS .402-500.01MEDIAN OPENING SPACING .402-500.02MEDIAN OPENING SPACING - EXAMPLES .402-500.03LEFT TURN LANES IN MEDIANS.44SECTION 6 – STRUCTURAL DESIGN .472-600.00CONCRETE BOX AND SLAB TYPE CULVERTS AND BRIDGES .472-600.01TYPE DESIGNATION.472-600.02PAVED APRON FOR BOX CULVERT AND BRIDGE OUTLETS .472-600.03CONCRETE BOX AND SLAB TYPE CULVERTS AND BRIDGES INSHALLOW FILLS .472-600.04STEEL BAR REINFORCEMENT (ROADWAY) .532-601.00HAUL ROADS .532-601.01HAUL ROAD DESIGN CONSIDERATIONS .532-601.02HAUL ROAD COMPENSATION .542-601.03HAUL ROAD TYPICAL SECTION .55SECTION 7 – EARTHWORK DESIGN .562-700.00EARTHWORK CONSIDERATIONS .562-701.00EARTHWORK BALANCES ON WIDENING OF EXISTING ROADWAYS .582-702.00SHRINKAGE AND SWELL FACTORS .582-703.00GRADING LINE THROUGH SOLID ROCK .592-ii
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:2-704.00PRESPLITTING OF ROCK EXCAVATION .602-705.00CAPPING ROCK FILLS .602-706.00TOPSOIL REQUIREMENTS FOR EARTHWORK BALANCES .602-707.00EARTHWORK BALANCES IN PLANS.61SECTION 8 – TRUCK CLIMBING LANES .642-800.00TRUCK CLIMBING LANE DESIGN .642-800.01LOCATION GUIDELINES .642-800.02CAPACITY ANALYSIS .652-800.03CRITICAL LENGTH OF GRADE .652-800.04DESIGN CRITERIA .712-800.05DOWNGRADES .752-800.06TRUCK SPEED PROFILE .75SECTION 9 – RETAINING WALL DESIGN.802-900.00RETAINING WALLS .802-900.01RETAINING WALL SHEET NAMES, NUMBER, AND ORDER IN PLANS.802-900.02DEVELOP THE RETAINING WALL GEOMETRIC LAYOUT SHEET .822-900.03RETAINING WALL ASSESSMENT AT SITE REVIEW .902-900.04GUIDELINES FOR CATEGORY ONE RETAINING WALLS .912-900.05GUIDELINES FOR CATEGORY TWO RETAINING WALLS .922-900.06DECORATIVE FACING ON RETAINING WALLS .932-900.07RETAINING WALL QUANTITIES .932-900.08R.O.W. FUNDING REQUEST AND R.O.W. REVISIONS .952-900.09CONSTRUCTION FIELD REVIEW, SUBMITTAL, AND REVISIONS .962-900.10RETAINING WALL FOOTNOTES ON CONSTRUCTION PLANS .962-900.11RETAINING WALL BARRIER SYSTEM REQUIREMENTS .97SECTION 10 - ROUNDABOUT DESIGN .982-1000.00 ROUNDABOUT DESIGN PRINCIPLES .982-1001.00 GENERAL ROUNDABOUT DESIGN CONSIDERATIONS .982-1001.01DESIGN SPEED AND DESIGN VEHICLE SELECTION FORROUNDABOUTS .982-1001.02HORIZONTAL ALIGNMENT CONSIDERATIONS FOR ROUNDABOUTS .992-iii
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:2-1001.03LONGITUDINAL GRADE CONSIDERATIONS FOR ROUNDABOUTS .1002-1001.04RIGHT-OF-WAY REQUIREMENTS FOR ROUNDABOUTS.1002-1001.05CONSIDERATIONS FOR HIGH SPEED APPROACHES AND RURALLOCATIONS FOR ROUNDABOUTS .1012-1001.06GRADING AND DRAINAGE CONSIDERATIONS FOR ROUNDABOUTS .1022-1002.00 GEOMETRIC DESIGN ELEMENTS FOR ROUNDABOUTS .1032-1003.00 ROUNDABOUT DESIGN CHECKS AND MEASUREMENTS .1072-1004.00 ROADWAY DESIGN CONSIDERATIONS FOR ROUNDABOUTS .1162-1004.01DETERMINING ROUNDABOUT LOCATION .1162-1004.02ROUNDABOUT PROXIMITY TO OTHER INTERSECTIONS .1162-1004.03ACCESS MANAGEMENT AND PRIVATE DRIVEWAYS ATROUNDABOUTS .1162-1004.04RAILROAD CROSSINGS AT ROUNDABOUTS .1172-1004.05SERIES OF ROUNDABOUTS .1172-1004.06ROUNDABOUTS USED AT INTERCHANGES .1172-1005.00 PEDESTRIAN, BICYCLE, AND PROWAG CONSIDERATIONS FORROUNDABOUTS .1182-1006.00 SIGNING AND PAVEMENT MARKING FOR ROUNDABOUTS .1202-1007.00 ROADWAY LIGHTING FOR ROUNDABOUTS.1202-1008.00 LANDSCAPING GUIDELINES FOR ROUNDABOUTS .1212-iv
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:INTRODUCTIONROADWAY DESIGN GUIDELINES AND STANDARD DRAWINGSRoadway Design Guidelines and Standard Drawings have been created to ensure thatthere is consistency in TDOT projects across the state. The Roadway Design Guidelines andStandard Drawings indicate the current recognized design standards for new construction orreconstruction of existing highways and shall be utilized while giving due regard to topography,natural conditions, availability of road material, and prevailing traffic conditions.Throughout these guidelines you will see the following terms used. To clarify the meaningsintended in this guide by the use of these terms, the following definitions apply: Designer – HQ Design, Project Development, or Consultant DesignerDesign Manager – HQ Design, Project Development, or Consultant Design ManagerDesign Team – HQ Design, Project Development, or Consultant DesignTechnical Report – Transportation planning reports (i.e. Transportation InvestmentReports (TIR), Transportation Planning Report (TPR)) developed by the StrategicTransportation Investments Division.2-v
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:This page is left blank intentionally.2-vi
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:SECTION 1 – CONTROLLING GEOMETRIC DESIGN CRITERIA2-100.00CONTROLLING CRITERIA FOR DESIGNThe following sections define both horizontal and vertical design elements including the10 controlling criteria for design as defined by the FHWA. The 10 controlling criteria can contributesubstantial importance to the operation and safety performance of any highway. A formal writtendesign exception process should be followed if any of the following criteria cannot be met. SeeSection 2-105.00 Design Exception Requests for further guidance on the process and requiredform. The 10 criteria are: Horizontal Curve Radius, Superelevation Rate, Lane Width, ShoulderWidth, Cross Slopes, Maximum Grade, Stopping Sight Distance, Design Speed, VerticalClearance, and Design Loading Structural Capacity.2-101.00HORIZONTAL DESIGNThe Horizontal Design consists of the horizontal alignment, typical section, slopedevelopment, and roadside design. The horizontal design elements are based off of severalfactors including design speed, rural or urban setting, type of terrain, AADT, and superelevation.The RD11-TS series - Typical Section and Design Criteria and RD11-SE series - SuperelevationDetails of the Roadway Standard Drawings shall be used to determine the horizontal curve radius,superelevation, lane width, shoulder width, cross slopes, and side slopes. The proposed designspeed and road type are listed in the technical report but shall always be reviewed and comparedto the standard drawings to ensure the correct typical section is listed based on road type.2-101.01HORIZONTAL CURVE RADIUS AND SUPERELEVATION RATESHorizontal curves provide transitions between tangent sections of roadway. Refer to RD11SE series - Superelevation Details of the Roadway Standard Drawings and Minimum RunoffLengths RD11-LR series of the Roadway Standard Drawings to review requirements for horizontalcurve radii based on speed of the road. Designers shall refer to these tables to determine the radiusrequired when designing horizontal alignments. Curve data is generated for each horizontal curveby CADD software programs and shall be shown on all projects. The Designer shall fill in anymissing data that is not automatically generated. See Figure 2-1, Curve Data.2-1
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:Figure 2-1Curve DataSuperelevation rates and run-off for horizontal curves are also shown in the RD11-SE series– Superelevation Details of the Roadway Standard Drawings and RD11-LR series - MinimumRunoff Lengths of the Roadway Standard Drawings. For urban projects, the maximum desiredsuperelevation rate is 0.04 ft/ft. For rural projects, the maximum desired superelevation rate is 0.08ft/ft. If the design superelevation rates cannot be met due to existing conditions, R.O.W. limitations,or other factors, a Design Exception is required. See Section 2-105.00 Design Exception Requestsfor further guidance.The most common type of horizontal curve is a simple circular curve; however, a spiralcurve can be used to provide a gradual transition between tangent sections and circular curves.This allows vehicles to more easily transition into and out of a curve while staying within the travellane. The superelevation tables in the RD11-LR series define when spiral curves shall be placedon projects. Spirals are recommended for curves 50 MPH or greater and superelevation of threepercent or greater. In Table 2-1, Example of Urban Superelevation Table Spiral Curves, the firstentry for a 50 MPH curve that requires a spiral curve is for a Radius of 2,290’.2-2
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:Table 2-1Example of Urban Superelevation Table Spiral CurvesOn isolated bridge replacement projects, intersection improvements, widening of existingroadways, etc., where use of spirals would provide no real benefit and/or would be difficult toconstruct, spirals will not be required. It will still be necessary to provide superelevation andsuperelevation lengths as shown on RD11-LR series.2-101.02TRAVEL, THROUGH, AND TURN LANE WIDTHSThe RD11-TS Series – Typical Sections and Design Criteria Roadway Standard Drawingsshow the lane width requirement for travel, through, and turn lanes for each road classification. Ifthe lane widths cannot be met due to R.O.W. restrictions, existing conditions, existing structures,etc., a Design Exception Request form shall be submitted. See Section 2-105.00 DesignException Requests for further guidance. Design Exceptions are generally not needed at thebeginning and ending of a project where lane widths transition down to existing conditions(example twelve feet proposed lanes transition down to existing eleven feet lanes). However, forother roads specified in the Design Exception criteria, the designer shall refer to the typical sectionstandards and evaluate all available information on the road to ensure the best, most economicallane width is proposed. If the Designer has questions or concerns due to the lane width, theyshould discuss it immediately with the Design Manager and Design Team as well as the StrategicTransportation Investment Division (STID) who furnished the technical report.2-101.03SHOULDER WIDTHSWidths for outside and inside (if applicable) shoulders are defined in each of the RD11-TSSeries – Typical Sections and Design Criteria Roadway Standard Drawings based on roadclassification. If the shoulder width needs to be reduced due to R.O.W. restrictions, existingconditions, existing structures, etc., a Design Exception Request form shall be submitted. SeeSection 2-105.00, Design Exception Requests, for further guidance.2-3
TDOT ROADWAY DESIGN GUIDELINESCHAPTER 2 GEOMETRIC DESIGN CRITERIAEnglishRevised:For lower volume roads, the outside shoulder may be graded only and not paved. For mostrural designs, the shoulder will have a greater portion that is paved with a 2’ portion that is not. (12’shoulder will have 10’ paved; 6’ shoulder will have 4’ paved; shoulders less than 6’ should be fullypaved). It is sometimes economical to pave out the additional 2’ and this should be discussed atthe R.O.W. field review.When calculating drainage spread, the inside and/or outside shoulder may be used tocarry a portion or all of the water. Often, initial drainage calculations include the entire shoulderwidth plus one-half of a travel lane for spread. On projects where the existing shoulders are usedfor spread on a closed drainage system, the Designer shall ensure that the reduced shoulder widthcan still accommodate the flow without increasing the spread more than the amount allowed intothe travel lane.2-101.04CROSS SLOPESThe cross slopes of travel lanes and shoulders are defined in each of the RD11-TS Series– Typical Sections and Design Criteria Roadway Standard Drawings based on road classification.If the cross slope does not match the standard drawing, a Design Exception Request andJustification form shall be submitted. See Section 2-105.00 Design Exception Requests for furtherguidance. The cross slope of a road is normal crown (-0.02 ft/ft) unless it is in a superelevatedsection. Shoulder cross slopes are usually -0.04 ft/ft. The slopes of the shoulder and roadwaypavement shall not exceed an algebraic difference of 0.07 ft/ft.Designers shall refer to the appropriate RD11-TS Series – Typical Sections and DesignCriteria Roadway Standard Drawings to determine what the change in cross slope should be formore than two travel lanes in the same direction. The Designe
Design Exceptions are generally not needed at the beginning and ending of a project where lane widths transition down to existing conditions (example twelve feet proposed lanes transition down to existing eleven feet lanes). However, for other roads specified in the Design Exception criteria, the designer shall refer to the typical section .
Part One: Heir of Ash Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26 Chapter 27 Chapter 28 Chapter 29 Chapter 30 .
local facilities. Design criteria are provided for the following facilities: Figure 32-2A "Geometric Design Criteria for Rural Two-Lane Minor Arterials," Figure 32-2B "Geometric Design Criteria for Rural Two-Lane Collectors," Figure 32-2C "Geometric Design Criteria for Rural Two-Lane Local Roads,"
TO KILL A MOCKINGBIRD. Contents Dedication Epigraph Part One Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Part Two Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18. Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26
The formula for the sum of a geometric series can also be written as Sn a 1 1 nr 1 r. A geometric series is the indicated sum of the terms of a geometric sequence. The lists below show some examples of geometric sequences and their corresponding series. Geometric Sequence Geometric Series 3, 9, 27, 81, 243 3 9 27 81 243 16, 4, 1, 1 4, 1 1 6 16 .
DEDICATION PART ONE Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 PART TWO Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 .
The first term in a geometric sequence is 54, and the 5th term is 2 3. Find an explicit form for the geometric sequence. 19. If 2, , , 54 forms a geometric sequence, find the values of and . 20. Find the explicit form B( J) of a geometric sequence if B(3) B(1) 48 and Ù(3) Ù(1) 9. Lesson 4: Geometric Sequences Unit 7: Sequences S.41
The first term in a geometric sequence is 54, and the 5th term is 2 3. Find an explicit form for the geometric sequence. 19. If 2, , , 54 forms a geometric sequence, find the values of and . 20. Find the explicit form B( J) of a geometric sequence if B(3) B(1) 48 and Ù(3) Ù(1) 9. Lesson 7: Geometric Sequences
been proven to be stable and effective and could significantly improve the geometric accuracy of optical satellite imagery. 2. Geometric Calibration Model and the Method of Calculation 2.1. Rigorous Geometric Imaging Model Establishment of a rigorous geometric imaging model is the first step of on-orbit geometric calibration
