CV314-3 Cloverleaf Interchange Design

Cloverleaf Interchange Design with AutoCAD® Civil 3D® Tomas Lendvorsky – Autodesk Strahimir Antoljak – Civil Engineering Institute of Croatia (IGH) Robert Vincent – Langan Engineering And Environmental Services

CV314-3 This session will present an excellent real world example of cloverleaf interchange design using Civil 3D. We'll cover modeling of four new ramps (two inner and two outer ones) by adding them to an existing half-cloverleaf interchange, and we'll explore the existing surface, design, and tie into an existing part of the cloverleaf, meeting AASHTO criteria. This 3D model is published via Autodesk® Freewheel™ and can be viewed at www.civildev.com/demo/3DCloverLeaf.htm.

About the Speaker: Tomas Lendvorsky, Autodesk, AEC Application Engineer Civil - EMIA CHS Countries Tomas is Application engineer responsible for AutoCAD Civil 3D in Emerging countries. Tomas has Master degree in Land surveying on Civil engineering faculty. In his current role he is involved in countryfication of the product in many countries and ensuring product suitability for different regions. He has 16 years working experience with Civil designing software. [email protected]

About the Co-authors: Strahimir Antoljak PE, CIO at Civil Engineering Institute of Croatia (IGH) In addition to 16 years of international experience in several civil engineering disciplines, Strah has a broad CAD/GIS and computer programming background. He used to teach Engineering Graphics with AutoCAD® at Rutgers University, participated in the advanced engineering design, CAD and database management, CAD support, in-house CAD training sessions, and custom applications programming. Strah is proud member of the Autodesk Geospatial Customer Council. [email protected] .

Rob Vincent, Langan Engineering And Environmental Services Rob is a highway engineer for Langan Engineering and Environmental Services located in Northern New Jersey. His experience includes numerous projects with the NJ Turnpike, Garden State Parkway, NJDOT, and other counties and municipalities. Recently, Rob has been involved in transportation projects in both Panama and Greece. Rob received his Bachelor of Science in Civil Engineering from Norwich University in Northfield, Vermont. [email protected]

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Cloverleaf Interchange Design with AutoCAD® Civil 3D®

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Table of Content About Speakers/Authors

Class Scope and Workflow

Survey

Horizontal Geometry

Existing road widening

Criteria Design

Creating Surface and Layout Profiles

Sections/Assemblies

Corridors, Surfaces

Surface, Reporting, Analysis

Overpass design


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Class Scope and workflow

Class covers cloverleaf interchange but principles shown in the class are applicable to many other interchanges.


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Workflow

Engineering Tasks Software Processes Software Features Used

1 Create 3D or import model of existing ground (EG)

Create surface object based on contours or import LandXML file

• Surface • LandXML Export

2 Evaluate 3D model of existing ground

Use various Civil 3D tools to evaluate, examine and analyze the 3D model of existing ground

• Surface Style and Labels • Surface Analysis • Orbit and Object Viewer • Quick Section • Water Drop • Inquiry Tool

3 Establish horizontal geometry for proposed ramps, and apply design criteria – design speeds and superelevation data (widening)

Create alignments, apply alignment styles and properties, including design speeds, superelevation data

• Alignments • Alignment properties (design

speed, superelevations) • Inquiry commands

4 Cut the profiles through EG surface to observe existing condition elevations

Create profiles, show them in the profile views and utilize inquiry commands to evaluate elevations and slopes

• Alignments • Profiles • Profile Views • Inquiry commands

5 Create proposed vertical profiles to meet EG. Apply design criteria to meet the applicable transportation standard

Create profiles by layout in existing profile vies that show existing condition. Apply design criteria to verify profile against local standards

• Alignments • Profiles • Profile Views • Inquiry commands • Transparent commands

6 Create typical sections to be utilized for ramp modeling based on contractual standards

Create required assemblies to be applied to the corridor

• Subassemblies • Assemblies

7 Create corridor ramps by applying its constituents; alignment, vertical profile, and assemblies

Create corridor models to include alignments, profiles, assemblies. Define targets such as EG

• Alignments • Profiles • Assemblies • Corridors

8 Generate FG surface, sections, spot elevations, reports, calculate volumes, quantity takeoff

Generate surface, use point, section and reporting tools

• Surfaces • Sections • Quantity takeoff • Reports


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9 Create overpass corridor, including bridge, abutment daylights, quantity takeoff

Create corridor models to include alignments, profiles, assemblies

• Alignments • Profiles • Assemblies • Corridors • Surfaces • Grading

Survey

Files related to Survey section of the class can be found in Step01_Survey in accompanying dataset.

Some thoughts on survey are discussed bellow.

Road design relies on existing condition. It is vital to explore, examine and evaluate existing conditions received by a surveyor. Survey data representing existing condition could generally be split into two data sets – planar data showing different features on the site (2D), and surface model (3D) used for creating profiles, vertical geometry, grading etc. Surface model often is referred to as existing ground (EG).

While planar survey entities and features call for thorough analysis and considerations of all design constrains, but no other action from a civil engineer, it is quite common that the civil engineer is required to generate the existing ground model.

Generally speaking survey data may involve liability; therefore the civil engineer should avoid shaping, modifying or altering any survey data, including generating EG. Rather, it should be set forth between the civil engineer and the surveyor that 3D model of EG surface should be generated and supplied by the surveyor.

Survey drawings representing existing conditions often contain contours. The contours are most likely generated from the 3D surface model with software used by the surveyor. So it would be prudent from civil engineer to ask for 3D surface model from a surveyor along with the contours.

There are various means of supplying the surface data. Of course the contours are one of them and it is quite common. However, by many professionals (re)creating 3D surface model based on the contours is considered the least adequate. Among other reasons, one is frequently emphasized; valleys and hills created from contours will turn flat, simply because software cannot guesstimate what happens within a lowest or highest contour thus creating a plateau at those locations. That further calls for finishing touches by the civil engineer, and this is where liability may come into a play.

In many cases civil engineer receives 2D linework in CAD drawing and 3D data in ASCII point file. To obtain true 3D Surface is necessary to create Surface from points and add Breaklines as Proximity type.

There can be more odd ways how designer receives info about EG, for example:


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Text with elevations at insertion point:

Text where elevation is only written within text:

Block with elevation as an attribute:


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Block with no elevation plus text with elevation info. Here we will use application written by Will Forty, Halcrow, UK which was posted on www.autodesk.com/fromthegroundup and you will find within posted documents. Following picture demonstrate settings within ToolBox Manager to call macro properly.

ASCII file containing XYZ coordinates with point description. You can use Civil 3D Survey functionality to import points and create linework. You will have to create Survey database with linear units meter and Figure Surface Database as follows:

System will create Survez points and figures which can be added as Breaklines into Surface


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There can be many more ways. These above mentioned examples will be shown during class.

On the other hand, if the 3D model of EG surface data is supplied there will be no need for interpretation by the civil engineer. Perhaps the best way to supply 3D model of EG surface is LandXML. Another good method of supplying EG surface is so called TIN file. TIN stands for Triangular Irregular Network and is common terminology among surveyors and land professionals. Even a simple drawing (dwg) containing 3D lines, mesh, or solids dumped from TIN, would save a lot of effort. All of the above are better ways of supplying EG surface as compared to contours.

In this chapter two ways of generating EG surface will be shown; most common one – from contours, and recommended one – from LandXML. Generally speaking XML stands for eXtended Markup Language, and its primary purpose is to facilitate the sharing of structured data across different information systems, particularly via the Internet. LandXML is XML suited to land professionals. Learn more on LandXML at www.landxml.org.


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Great advantage of Civil 3D are dynamic models, including dynamic surface models. This practically allows the civil engineer to generate EG from contours, and at the same time request LandXML or TIN file from the surveyor, if it has not been supplied at first place. So when the 3D model of EG surface eventually arrives, the one generated from contours can be replaced at any stage of design, not causing any delays, and with all other Civil 3D objects relying on the surface automatically being updated.

Horizontal Geometry (Geometry based)

Files related to horizontal Alignment part of interchange design are saved in folder Step02_HVGeometry in accompanying dataset.

Alignment is widely used multipurpose object. It can be used to depict utilities, streams, rivers, tunnels, it is used for pipe networks design, rail road design, and of course road design.

The alignment is also rather complex object with a lot of properties. However, you do not need all the properties for each purpose you use the alignment for. For example, when using the alignment for pipe networks you would not need to set the alignment’s Superelevation property, but rather geometry only. Thus the alignment’s geometry will be considered separately.

The most simple way to create alignment, concerning the geometry, is to create a polyline and then convert it into the alignment. You can accomplish that by using Create Alignment By Polyline from the Alignment menu.

But alignments can get more complex, especially in the transportation field. You may need to create compound alignments, consisting of any combination of tangents, arcs and spirals. While creating compound alignments, you may choose to impose different geometry constrains on different alignment portions. In Civil 3D you can add constraint-based fixed, free, or floating entity (tangent, curve or spiral) to an alignment.

Fix entity has zero degree of freedom and is fully defined by user. Floating entity has one degree of freedom which will be lost by connecting to entity which has been already fixed. Free entity has two degree of freedom which will be lost on two, already fixed entity. It will ensure tangency on both ends.

You may explore these and other numerous options that can be found on the Alignment Layout Tools. Also you are encouraged to explore PlayGround2.dwg provided with the dataset in Step02_HVGeometry folder. This drawing demonstrates application of majority tools found on the Alignment Layout Tools.


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Criteria Design

Design Criteria is new feature in AutoCAD Civil 3D 2009. If properly used it can be great help in expediting the design process. Files related to design criteria are saved in folder Step02_HVGeometry in accompanying dataset

Criteria-Based Design Features

Feature Description Location

Criteria-based alignment design Provides the ability to verify that alignment design meets the minimum standards required by your local agency. Design speed and a minimum radius, transition length, and default attainment method can be specified. For more information, see Criteria-Based Alignment Design in Help.

Alignments menu > Create Alignment By Layout > Design Criteria tab

Alignments menu > Create Alignment From Polyline > Design Criteria tab

Alignment Properties dialog box > Design Criteria tab

Criteria-based profile design Provides the ability to verify that profile design meets the minimum standards required by your local agency. Minimum K values for stopping sight, passing sight, and headlight sight distance can be specified at specified design speeds. For more information, see Criteria-Based Profile Design in Help.

Profiles menu > Create Profile By Layout Design Criteria tab

Profile Properties dialog box > Design Criteria tab

Criteria-based design checks (user defined criteria not included in the design criteria file)

Provide the ability to create and apply custom formulas to validate that an alignment or profile meets minimum standards not contained in tabular form. For more information, see Alignment Design Checks in Help.

Toolspace Settings tab > Alignment collection > Design Checks

Toolspace Settings tab > Profile collection > Design Checks

Criteria-based design reports Provides reports to compare alignment and profile parameters with specified design criteria.

General menu > Reports Manager

Alignment Design Criteria Verification and Profile Design Criteria Verification reports


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Design Criteria File

A design criteria file is an XML-based file that contains roadway design standards, or more precisely, the design criteria file contains the standards tables that specify appropriate minimum design standards for alignments or profiles.

Design criteria files containing A.A.S.H.T.O. standards in both metric and imperial units are included with AutoCAD Civil 3D, and it can be found in the following (default) location: C:\ProgramData\Autodesk\C3D 2010\enu\Data\Corridor Design Standards\Metric\_Autodesk Civil 3D Metric Roadway Design Standards.xml

If your local agency standards differ from the standards in the supplied design criteria files, you can use the Design Criteria Editor (see figure) to customize the file to support your local standards. You can run Design Criteria Editor from Alignments or Profiles menu.

Note: If you use a custom a design criteria file, you must save it to a shared server to which all members of your design team have access. If you send a drawing that uses a custom design criteria file, you must send the design criteria file with the drawing.


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Alignment Design Criteria A design criteria file may contain the following alignment design criteria: • Minimum radius at a given design speed • Minimum transition length at a given radius • Superelevation attainment method • Superelevation rate at a given radius (explained later in handout).

Note: Compound spiral length is not validated against the design criteria file. You must use design checks to validate compound spiral length.

You can specify roadway design standards including minimum radius, transition length values and superelevation attainment method through the alignment properties, see figure.

The design criteria file has three sections that you can use to calculate superelevation rates and superelevation transition stations on an alignment.

Minimum Radius Tables. A table of superelevation rates that you can apply to different types of roadways as a function of curve radius and design speed.

Transition Length Tables. A table of values you can use in the Superelevation Attainment Method formulas. You can use the table to calculate the distances between the critical superelevation transition points for different types of roadways as a function of curve radius and design speed. In many cases, the transition length tables provide the actual length of transition of superelevation runoff.


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Superelevation Attainment Methods. Specifies how superelevation is applied, and the method that is used to calculate superelevation transition stations for different types of roadways. Each defined method specifies the formulas used to calculate the distances between the critical superelevation transition points. AutoCAD Civil 3D supports two methods of superelevation attainment:

• Standard. Superelevation transition method that requires removal of adverse crown. This method is typically used on undivided, crowned roadways and divided roadways with crowned or planar sections.

• Planar. Superelevation transition method that does not involve removal of adverse crown. This method is typically used on undivided, planar-section roadways, such as ramps and service roads.

In the design criteria file, each attainment method, minimum radius table, and transition length table have unique, defined names.

When you create the alignment, the minimum standards from the design criteria file ensure that the horizontal curves comply with the minimum standards required by your local agency.

If the design parameters for a sub-entity violate the minimum values established in the design criteria file, a warning symbol appears both on the sub-entity in the drawing window (see figure) and next to the violated value in the Alignment Entities Vista and Alignment Layout Parameters Window. When you hover the cursor over a warning symbol, a tooltip displays which standard has been violated and how to correct the violation. The display of the warning symbol is controlled by the alignment style.

Alignment Design Checks Some alignment design criteria are not available in table form in the design criteria file. For these criteria, you may define design checks to validate design standards.

The tables contained in the design criteria file contain the most commonly used criteria for alignment design. Other criteria may be checked by using mathematical expressions, which in the context of criteria-based design are known as design checks.

Design checks are created and managed in the same manner as label expressions. Use the Design Check Editor Dialog Box, which is similar to the Expressions Dialog Box, to create and edit design checks. To apply a design check to an alignment, you must add it to a design check set (similarly to an alignment label set).


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You can create design checks for lines, curves, spirals, and tangent intersections, which are groups of multiple line, curve, and spiral entities. Design checks validate the type of entity for which they were created, whether the entity is independent entity or a sub-entity in a tangent intersection group. For example, a curve design check validates a curve that is part of a spiral-curve-spiral group. However, a design check that validates the properties of a curve in spiral-curve-spiral groups does not validate the same properties of a standalone curve.

Design checks differ from label expressions in that they always return a true or false value. For example, you can create a design check to verify minimum tangent length. If a tangent length is greater than or equal to the minimum value defined in the design check, no notification is issued. If a tangent length is less than the minimum value defined in the design check, a warning notification is issued.

For more information, see Expressions and Labeling Alignments Using Label Sets in Help file.

Alignment Design Reports You may generate a report that documents validations or violations in the alignment design. The design criteria report identifies whether each sub-entity within a given station range violates or meets the appropriate design criteria and design checks.


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Profile Design Criteria

A design criteria file may contain standards tables for minimum K values at specified design speeds. Minimum K tables for the following distances are available: • Stopping Sight Distance • Passing Sight Distance • Headlight Sight Distance


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In similar manner to alignments you may define profile design checks and generate profile design reports.


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Design Criteria Example

Design check provides possibility to build set of criteria for Line, Curve, Spiral or Tangent intersection within DWT file. System checks designed values against values in Design Check Sets and displays Warning symbol, if violated.

If you are familiar with Expressions, you will find very easy to build your own design checks. The following example checks curve radius. Warning symbol highlights the Alignment section, where rules are violated. The Following snapshot shows two warnings. The first one is coming from XML Design criteria file, the second from Design check.

Design Check Design speed [km/h] Radius [m] 60 350 50 300 40 250

Notes: Symbol size is derived from active zoom window. Symbol can be made invisible in Alignment style. Symbol is not plotted.


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Superelevation Example

This is an example of ramp EN superelevation conducted manually.

The ramp superelevation was developed utilizing the calculated rate of change (expressed as percent of change per meter traveled) based on the AASHTO Green Book. The methodology utilized to calculate the rate of change is as follows:

Step 1: Determine required superelevation based on design speed and curve radius. Ramp EN has a radius of 50 meters and a design speed of 40km/hr. According to Exhibit 3-26 in the AASHTO Green Book the ramp requires a superelevation of 5.9%.

Step 2: Calculate rate of change based on AASHTO Superelevation Runoff for Horizontal Curves (Exhibit 3-32). To summarize, Superelevation Runoff is the distance required to go from full superelevation to a zero percent cross slope. We have a maximum cross slope of 5.9% Exhibit 3-32 states the length of runoff for 5.9% at 40km/hr (for one lane being rotated) is 31 meters. We calculate the rate that the superelevation changes like this: 5.9% divided by 31 meters = 0.19% per meter.

Step 3: Calculate superelevation on the ramp. Begin at the entrance gore. We want the last point of a normal cross slope (2%) to be at the striped gore. This is at Sta. 3+010. Now we calculate the distance required to achieve full superelevation. We know we want to rotate the pavement from 2% to 5.9%. This is a total change of 3.9%. We calculate the distance required to achieve this change by dividing the total percent change by the rate of change that we calculated previously. 3.9% divided by 0.19% per meter = 21 meters. Using this we determine that we achieve full superelevation at Sta. 3+031. We use the same process to determine where the full superelevation ends by working backwards from the striped gore on the other end of the ramp at Sta. 3+192. Sta. 3+192 minus 21 meters = Sta. 3+171. Full superelevation ends at Sta. 3+171.

Step 4: Determine inside shoulder cross slopes. The inside shoulder cross slope is 5%. As the lane rotates up to the 5.9% maximum cross slope, so will the shoulder. We must determine the last station on the ramp that the shoulder is 5%. We do this by working backwards from the station of full superelevation. Full superelevation is achieved at Sta. 3+031. We need to determine the distance required to rotate the shoulder from 5 % to 5.9%, for a total change of 0.9%. 0.9% divided by 0.19% per meter = 5 meters. Therefore the station at which the shoulder begins to rotate is Sta. 3+031 minus 5 meters = Sta. 3+026. We do this again at the other end of the ramp to determine where the inside shoulder rotates back to 5%. This is calculated to be at Sta. 3+171 plus 5 meters = Sta. 3+176.

Step 5: Determine outside shoulder cross slopes. The outside should will have a cross slope of -2.1%. This is because we must maintain a maximum rollover of 8%. Full superelevation is 5.9%. -2.1% minus 5.9% = 8%. Since the ramp is at full superelevation for the majority of its length we will hold the outside shoulder a constant -2.1% for ease of construction.


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The resulting table is shown:

Smoothing Curve Length

Left Side

Right Side

No. Superelevation Region Station Description

Smoothing Curve Length

Outside Shoulder

Outside Lane

Outside Lane

Outside Shoulder

1 3+000.00m Begin alignment 0.000 -2.10% 2.00% -2.00% -5.00%

2 1 3+010.35m End normal crown 0.000 -2.10% 2.00% -2.00% -5.00%

3 1 3+030.00m End normal shoulder 0.000 -2.10% 5.00% -5.00% -5.00%

4 1 3+036.00m Begin full super 0.000 -2.10% 5.90% -5.90% -5.90%

5 1 3+166.00m End full super 0.000 -2.10% 5.90% -5.90% -5.90%

6 1 3+172.00m Begin normal shoulder 0.000 -2.10% 5.00% -5.00% -5.00%

7 1 3+192.00m Begin normal crown 0.000 -2.10% 2.00% -2.00% -5.00%

8 3+212.51m End alignment 0.000 -2.10% 2.00% -2.00% -5.00%

Observe Set Superelevation Properties button shown with red arrow. This is where superelevation calculation can be performed automatically via the XML-based design criteria file that contains applicable roadway design standards.


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Many so called AutoCAD Civil 3D Country Kits which, among other things, include design criteria file have been developed and can be downloaded from the following Autodesk web page: http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=7271531&linkID=9240698#2010

Creating Surface Profiles

There are no too many new things related to creating surface profiles as compared to earlier versions or other AU classes that cover surface profiles, thus not much time will be spent on it.

Creating Layout Profiles (criteria based)

The criteria-based design feature allows a layout profile to be validated against local design standards. You can select a design criteria file and/or a design check set using either the Create Profile - Draw New dialog box when you create the layout profile, or the Design Criteria tab of the Profile Properties dialog box after it has been created.

Design Criteria File is a file that contains minimum design standards for alignment and profile objects. The design criteria file may be customized to support local design standards for design speed, superelevation, and minimum speed, radius, and length of individual entities.

Design Check is a user-defined expression used to verify that an entity meets the minimum design standards that were established for profile object. Design checks may be defined for different entity types, such gradient and vertical curve. A design check must be saved in a design check set to be applied to an alignment or profile.

Design Check Set is a user-defined collection of commonly used design checks. You specify a design check set either during alignment or profile creation, or after creation using the object properties dialog box.

Use the criteria-based design feature to apply agency-specific standards to a profile.

The criteria-based design feature provides the ability to verify that your profile design meets the minimum standards required by your local agency.

To create a profile using design criteria, use the same basic workflow that you use to create a profile without design criteria.

When you lay out the profile using fix, floating or free entities, the appropriate minimum values specified in the design criteria file are displayed on the command line. You can either accept the default minimum value for a given sub-entity, or specify a new value. When you lay out profile using IP method, system will automatically adopt values from criteria file.

When you lay out the profile, the appropriate minimum values specified in the design criteria file are displayed on the command line. You can either accept the default minimum value for a given sub-entity, or specify a new value.

Agency standards, which are typically based on superelevation and design speed requirements, are contained in the customizable design criteria file. When you create the profile, the minimum standards from the design criteria file ensure that the vertical curves comply with the minimum standards required by your local agency.

http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=7271531&linkID=9240698#2010�


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If the design parameters for a sub-entity violate the minimum values established in the design criteria file, a warning symbol appears both on the sub-entity in the drawing window and next to the violated value in the Profile Entities Vista and Profile Layout Parameters Dialog Box. When you hover the cursor over a warning symbol, a tooltip displays which standard has been violated and how to correct the violation. The display of the warning symbol is controlled by the profile style.

Some profile design criteria is not available in table form in the design criteria file. For these criteria, you can define design checks to validate design standards. A design check must be saved in a design check set to be applied to a profile.

You can generate a report that documents validations or violations in the profile design. The design criteria report identifies whether each sub-entity within a given station range violates or meets the appropriate design criteria and design checks.

File related to create surface profile is saved in folder Step02_HVGeometry in accompanying dataset.

Existing road widening

To assure Ramp NE Profile smoothly comes to existing road, we will first widen lanes. we will use corridor functionality for widening. The very first step will be Alignment which will sit at existing inner ETW measured by surveyors. You can use Create Alignment from Object or Alignment Creation tools – Vest Fit elements. The second possibility will be demonstrated during the class Fixed Curve–Best Fit and Floating line–Best Fit .Always check the elements directions.

To create Profile will be very easy – we will Create Surface Profile and it will become our designed Profile.

Assembly – to create assembly we will use Rehab Subassembly OverlayWidenMatchSlope1 which will extend existing lanes crossfall It is important to set correct Corridor targets.


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Where:

Main Road Inner ETW – Alignment created by Best Fit

MR Outer ETW existing – Grading Feature line created from polyline and elevation assigned from EG Surface.

At the end we will create Surface from Top Corridor links and we will draw it within Ramp NE Profile view. Now we can adjust Design Profile to fit this Surface.

File related to road widening procedure in folder Step03_RoadWidening in accompanying dataset.

Sections/Assemblies

Assembly and subassembly objects create the primary structure of an AutoCAD Civil 3D corridor model.

Assembly is the collection of subassemblies that form a corridor section. Corridor is a longitudinal 3D model that can be used for road design, railroad design, riverbed modeling, tunnel modeling, etc

You create an assembly object by adding one or more subassembly objects, such as travel lanes, curbs, and side slopes, to an assembly baseline.

You should take assemblies and subassemblies seriously. When properly created the assemblies can cut the design time dramatically, especially in the process of reiterating the design caused by client’s new requests, new inputs by authorities or constraints encountered during the design.

Carefully selected and composed assemblies will help you dramatically reduce the time in generating the following:

• proposed surface • cross sections and cross section labeling • material quantities • animation and presentation resulting from 3D model based on the assemblies • featurelines and breaklines (fault lines), that can be dynamically remain linked to the corridor or

turned into alignments.

There are 80+ subassemblies that come with AutoCAD Civil 3D out of box. In addition to that, you may create your own custom subassemblies.

A subassembly can be as simple as a point, or a line and as complex to have decision making routines embedded in it. AutoCAD Civil 3D’s open architecture allows for programming subassemblies which means that virtually there are not limits to what programmers can do with assemblies.

If you dig deep enough you will find some subassemblies intelligent enough to sense the environment which the corridor is running through, hence suppressing or activating different elements along the corridor. For example, given the surroundings a subassembly can daylight along one portion of the


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corridor and given the circumstances ‘decide’ to put a retaining wall or ditch along other portion of the corridor.

How you will use assemblies and subassemblies depends on your company’s setup and CAD management. Normally most frequently used assemblies would be ready-made and deployed by the CAD manager to all users via content browser and palettes. For such cases a user would simply drag the assembly from the palette, drop it to a drawing and simply apply it to a corridor.

Occasionally you may be challenged to put together some assemblies on your own, or with help of CAD manager, or even by instructing a programmer who would create an subassembly with new functionality based on your input.

Consider investing significant amount of time when composing assemblies, anywhere between couple of hours to couple of days per assembly. Keep in mind that once you composed typical assemblies, you will reuse them in future projects so document them properly. They can provide you with great benefits mentioned above, when properly handled.

It is important to note that not all subassemblies in AutoCAD Civil 3D are located on a tool palette by default. All subassemblies are stored in the Content Browser, and you can add subassemblies that you use frequently to a tool palette for easy access.

To explore subassembly properties, right-click on it on the tool palette and from the floating menu select Help… This will open description of the subassemblies.

In the exercise that follows you will use LaneOutsideSuper, ShoulderVerticalSubbase, DaylightGeneral and RetainWallVertical subassembly from the Metric – Road subassembly. To explore its capabilities, right click on it and select Help. It is critical to notice that LaneOutsideSuper subassembly is aware of alignment’s superelevation property.

File related to creating surface profile is saved in folder Step04_Ramp in accompanying dataset.

Corridors

You can use AutoCAD Civil 3D corridors to model longitudinal 3D models such as roads, highways, railways, riverbeds, tunnels, etc.

Corridor objects are defined by associating a baseline (guiding alignment) and its finished grade profile layout with sectional design elements (assemblies), and other data (e.g. surfaces, secondary alignments, etc). Various assemblies can be applied for different ranges of stations along the corridor baseline. Additionally, the corridor contain multiple baselines, each baseline representing one longitudinal body, meaning that one single corridor object can comprise say multiple roads intersecting each other.

A corridor can define and display components, such as:

• Feature lines connecting points along the point codes, which are defined in the subassemblies (used to create the assemblies).

• Embedded surfaces (using link codes and feature lines) • Rendering support • Slope hatching support

Corridors are created from and based on existing AutoCAD Civil 3D objects, which include:


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• Alignments (horizontal). Primarily used by a corridor as its centerline, but it can be also used as a subassembly target. Some more sophisticated subassemblies allow for horizontal targets. Example would be an alignment representing Edge Of Pavement (EOP) where widening required. In such scenario the subassembly can be targeted to the EOP alignment following any desired curving shape rather than being parallel to the center of road.

• Layout Profile (vertical). Used to define vertical geometry of the finished grade along the horizontal alignment. Optionally, the profiles can be used to define subassembly targets. Some more sophisticated subassemblies allow for vertical targets (in addition to horizontal targets). Example could be non standard superelevation, where EOP alignment can have associated layout profile meeting those superelevation requirements and serve as the subassembly’s target both horizontally (widening) and vertically (superelevation).

• Assemblies. Represent a typical section of a corridor. Assemblies comprise one or more subassemblies connected together.

• Targets. The most common target is surface, but targets can be also polyline, grading feature line or survey figure.

File related to creating surface profile is saved in folder Step04_RampNE in accompanying dataset.

Surface, Reporting, Analysis

After you have created a corridor, you can extract data from it, including surfaces, feature lines (as polylines, alignments, profiles, and grading feature lines), and volume (quantity takeoff) data.

Surfaces

Surfaces are broad subject in AutoCAD Civil 3D. In terms of corridors, surfaces are final product. The corridor serves as a mold to a surface. Once the corridor is completed a number of surfaces can be extracted from it resulting from the various combination of corridor’s links, feature lines and shapes. In this lesson you will extract corridor’s top surface and merge it into EG surface.

Civil 3D 2010 has new functionality to create Corridor Surface. We will use this functionality to create Surface from Pave links (eg. on pavement only) and using Slope Arrow style we can check, if water will run-off the ramp. If not, we can simply move part of the Designed profile and thanks to dynamic model we will instantly receive updated Corridor, Sections etc (see below).

To create correct trimmed Surface, use Subassembly MarkedPoint to add missing Point Codes. In attached example Assembly Ramp NE Transition MarkedPoint with Point Code ETW at pavement edge of RightShoulder_RampNE_Transition.

Tip:

Sections

Use sections (also referred to as cross sections) to provide a view of the terrain cut at an angle across a linear feature, such as a proposed road.

Typically, sections are cut across horizontal (plan) alignments at a specified station interval using specified swath widths. These sections are then plotted, individually for a station, or as a group for a range of stations.


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AutoCAD Civil 3D handles the creation, management, and plotting of sections with the following components:

• Sections. Terrain elevations that cut across surfaces, including corridor surfaces, along each sample line, which are associated with a specified sample line group. Elevations are sampled at each of the sample line XY vertices and also at locations where the vertical plane defined by the sample line intersects with surface edges.

• Section Views. For each sample line, views displaying some or all of the sections sampled at that sample line. This graphical view has both abscissa limits based on the length of corresponding sample line and ordinate values based on the minimum and maximum elevations from the set of sections it is displaying.

In AutoCAD Civil 3D, section data is defined and displayed using sample lines, sections, and section views, all of which are managed through a collection called a sample line group. An alignment can have more than one sample line group associated with it, each having a unique set of sample lines and sections.

Quantity Takeoff

Use the quantity takeoff functionality to extract and report sectional material volumes, based on sample line groups.

You can create tables and reports about:

• Volumes along an alignment, comparing various design surfaces and existing ground surfaces.

• Volumes for shapes, which are closed cross-sectional areas created by a single subassembly. For example, a curb (a closed area within a concrete curb or curb and gutter).

• Volumes between various (designed/grading/existing) formations.

Quantity takeoff reporting uses criteria settings that are portable and extensible. You can create criteria based either on existing data including surfaces and sample line groups or on standard surface names.

You prepare to generate quantity takeoff information by creating a list of materials and applying the predefined criteria to it, mapping existing surfaces or other objects to the names in the criteria. After the material list is generated, the settings and volume calculations are stored with the sample line group and can be used to generate tables and reports.

You can display quantity takeoff information using standard AutoCAD Civil 3D table formats or view and export it in an XML format file.

Further exploration. Check the Toolbox under General Menu. In the toolbox you will find valuable reports under Alignment, Corridor, Profile and Surface nodes.

File related to creating Sample Line Group, Section Views and Quantity Takeoff is saved in folder Step04_RampNE in accompanying dataset.


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Overpass

To design overpass is very similar to ramp. Designing Horizontal and Vertical geometry is the same. During Vertical geometry design you have to be aware of letting enough space for crossing road clearance. To check the clearance, you can for example create TIN Volume Surface and using Elevation bands analysis to determine, if entire girder bottom has sufficient vertical distance to road below. Another possibility is to use Inquire tool brought by Subscription Advantage Pack – Calculate Vertical Distance between Entities. It is very easy to create polyline, convert to Grading Feature line, assign elevation from Surface and then examine the level difference at intersection.

To accomplish Corridor design we will need three different Assemblies - road, abutment and bridge. Road Assembly can have any required shape. Abutment is in fact road Assembly without daylight subassemblies. To define Bridge assembly, you can use three different approaches:

- Create Bridge subassembly from polyline

- Use one of Bridge girder from ToolPalettes

- Use combination if standard subassemblies and generic links

Each approach has advantages and disadvantages at the same time. Me personally I recommend to use the last possibility. It gives user advantage to create intelligent subassembly which can be used for different projects and purposes.

To create abutment daylights, you can use two different approaches: Grading or Corridor design. In both cases first create polyline on the outer edges of abroad.

Grading: convert polyline onto Grading Feature line and assign elevations from Corridor surface. Then use Grading Creation tools to create required daylights. If you move overpass profile, you have to re-assign elevation as it is not dynamically linked to Corridor Surface. Advantage of this solution is easy volumetric calculation and possibility to use Elevation editor to modify feature line vertically.

Corridor: convert polyline onto Alignment and add very small radiuses (let say 1m). create Surface profile using Corridor surface. This profile will become designed profile and is dynamically linked to the Surface. If you change overpass profile, abutment profile will remain in sync. Create simple Assembly containing the only subassembly – generic link LinkSlopeToSurface. Using all above mentioned objects, create Corridor.

When creating Corridor Surface boundary you cannot find function Corridor extents as outer boundary… you can use Add Baseline within Parameters tab with Profile (and nothing else) and this functionality will appear.

Tip:

File related to creating surface profile is saved in folder Step05_Overpass in accompanying dataset.

CV314-3 Cloverleaf Interchange Design

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Transcript of CV314-3 Cloverleaf Interchange Design