Basic Highway Plan Reading, Exercises of Construction

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Basic

Highway Plan

Reading

Inspector

ualification

Series

FORWARD

This Plan Reading Course is to present a step-by-step procedure on how to read, interpret, and relate to a standard set of roadway plans; to help identify and interpret symbols used in a standard set of plans; and to help develop the necessary skills to interpret a set of plans in non-technical terms to laypersons (property owners and others). Along with this manual you will use plan sheets & standards that specifically relate to it. The plan sheets/standards included have been reduced to half their original size so they can be handled more easily.

Since it is our intent to provide you with a well rounded exposure to highway construction plans, you may be asked to look at a plan sheet from a particular project. Please ascertain that you are looking at the correct set of plans for the text that you are reading and the questions you may be asked to answer.

TO THE STUDENT

This is a self-instructional study course. The subject matter is arranged so that you may work at your own speed. Each part of the course builds on the information that has preceded it, and prepares for information to follow. Most of the parts present new information. Some parts review important facts that have been introduced to you earlier in the program.

The idea behind this method is for you to read and study the information, actively participate by writing or checking off answers to questions, then find out immediately if you are correct. This method reinforces what you have read and enables you to retain what you have learned for a longer period of time. The retention of information from a self-instructional study course should be far greater than from a lecture or textbook.

To get the most from this course, start at the beginning. Read each section as it comes preparing you for the next section. To make reading easier, the information is divided into frames. At the end of some frames, you will find questions. By answering these questions, you will be able to retain what you have just read longer than by lecture or discussion. The answers to these questions are at the end of this document.

CHAPTER 1: BEGINNING TO READ PLANS

GENERAL INFORMATION

A requirement occurring in one of the parts of a Colorado DOT contract is as binding as though occurring in all. The Standard Specifications, Supplemental Specifications, Plans, Special Provisions, and other supplementary documents are all part of the contract. In case of a discrepancy, certain parts of the contract govern over others pursuant to subsection 105.04 of the Standard Specifications.

Supplemental Specifications govern over Standard Specifications; Plans govern over Supplemental Specifications and Standard Specifications; Detailed Plans govern over the Standard Plans; Standard Special Provisions govern over Plans, Supplemental Specifications, and Standard Specifications; and Project Special Provisions govern over Standard Special Provisions, Plans, Supplemental Specifications, and Standard Specifications.

In the event such errors or omissions are discovered, the Engineer will then make such corrections and interpretations, as may be determined necessary for the fulfillment of the intent of the Contract.

The Specifications contain all directions, provisions and requirements pertaining to performance of the work. They describe the materials and construction requirements in sufficient detail to allow for accurate and competitive bids. They also include contract management details that allow CDOT to control the contract.

The specifications cover the Bidding Requirements and Conditions, the Award and Execution of the Contract, the Scope of Work, the Control of the Work, the Control of Material, the Legal Responsibilities to the Public, the Prosecution and Progress of the work, the Measurement and Payment, the Construction Details, and the Materials Details.

The outline used for the Construction Details sections 200-600 is:

1. Description
2. Materials
3. Construction Requirements
4. Method of Measurement
5. Basis of Payment

The Plans are drawings comprised of the Standard Plans and Detailed Plans provided by the department, which show the location, character, dimensions, and details of the work.

The Standard Plans (M&S Standards) simplify the design process by detailing standard design and construction practices which are utilized on all projects. This

provides for uniformity, cheaper prices, and higher quality on CDOT projects. Examples include guardrail, inlets, signs, striping.

The Detailed Plans show the specific requirements and qualities of an individual project. For example, project location, general notes, typical section, items and quantities, plan sheets, tabulation sheets, structure details, sign quantities, and details for items not included in the Standard Plans.

The Standard Special Provisions are comprised of additions and revisions to the Standard Specifications that are included as appropriate on a group of projects. Sometimes they apply to all projects.

The Project Special Provisions are comprised of revisions to the Standard Specifications that are specific to a particular project.

Why do we have Standard Plans and Standard Specifications? The most obvious reason is to ensure uniformity and quality of construction on our projects. The other is that, on projects with FHWA oversight, the plans, specifications and estimate for each project must be approved by FHWA prior to advertisement. In the absence of pre- approved standard specifications and standard plans, all of the required specifications and plan information would have to be included and approved in each package submitted to FHWA. Once Standard plans and specs have been approved by FHWA they may be used on Federal Aid projects without further review.

When the Plans for a contract are completed, the sheets are normally placed in a specific order. (The following list is used as a general guide and is sometimes changed to better fit an individual project).

x Title Sheet x Index (Generally included on the Title Sheet) x M&S Standard Plans List x Typical Sections x General Notes x Summary of Approximate Quantities x Structure Tabulation x Earthwork Summary x Surfacing Tabulation x Guardrail/Fencing/Delineator Tabulation (Included on separate sheets on large projects) x Plan and Profile Sheets x Interchange Plan Sheets x Profile of Ramps or Sidestreets or Driveways x Bridge Plans and Details x Retaining Wall Plans and Details x Structure Cross Section (Culvert Profiles)

PROJECT LOCATION MAP

In the center of the Title Sheet is a LOCATION MAP. This view shows the beginning station and the ending station of the project, and other features to help identify the location.

SHEET IDENTIFICATION-TITLE BLOCK Now look at the lower edge of the Title Sheet. Each sheet in a set of plans has a similar box for standard identification for each sheet. The box lists the project number, project code number, the Plan Sheet number, Sheet Revisions, designer and computer file information, and the plan sheet name.

PLANS REVISED AND PLANS COMPLETED

A box is provided on each plan sheet to list each time the plan sheet has been revised. A date is placed in the box for each of these occurrences.

SCALE Roadway plans are drawn to scale in order that they might be presented on easy-to-use sheets. Roadway plans are normally drawn with an engineer’s scale. Structure plans are generally not drawn to scale.

The engineer’s scale is one that expresses scale as 1 inch = 10 feet, 1 inch = 20 feet, 1 inch = 50 feet, 1 inch = 1 mile, etc. It is usually 1-foot long and may be triangular or flat. The scales are divided into decimal parts of an inch such as 1/10th inch, 1/20th inch, etc.

The triangular, or six-scale scale, has scales with 10, 20, 30, 40, 50, and 60 divisions to the inch.

The scale on which the Title Sheet was plotted is shown graphically on the Title Sheet. Plan sheets, however, are plotted on various scales depending on the need for detail, etc., and are notated as such on the respective plan sheets.

PROJECT LENGTH AND DESIGN DATA

A Tabulation of Length and Design Data box is shown on the Title Sheet noting the approach to project, length of the project, bridges and no-work areas, when applicable. In the design of a highway, traffic data is used to determine the number of lanes and the depth of paving. This data is shown in this box as well.

INDEX OF SHEETS An index of sheets is required for each set of construction plans to help the user in identifying what sheets are in the set of plans. The index is normally included on the cover sheet, but may be a separate sheet directly following the title sheet.

Answer the questions concerning the title sheet:

1-1 What gives you the basic description of the project? 1-2 What gives you the beginning and ending of the project? 1-3 Where is the location of the project shown?

Using Plan Sheet #1 , answer the following questions: 1-4 What is the name of this project? 1-5 What is the total gross length of this project in miles? 1-6 On what sheet numbers would you find the retaining wall plans?

be slightly longer than 24. All the dimensions shown by level lines are Horizontal Distances. Explanations of Slopes will be discussed later in this book. Use Plan Sheet #2 , Tangent Section, and answer the questions:

2-1 What is the total thickness of the concrete pavement? 2-2 What is the thickness of the ABC leveling course used under the concrete pavement? 2-3 How wide is the median? 2-4 What is the total width of the concrete pavement for the northbound lanes?

CHAPTER 3: GENERAL NOTES

The General Notes sheet contains a list of notes that clarify items that are not satisfactorily covered elsewhere in the specifications or plan details. On smaller projects, a page of general notes include the majority of all plan notes. On larger projects each specialty (i.e., bridge, traffic, landscaping) may contain its own area of general notes. This section may contain notes that describe pay items that do not require a tabulation, such as Clearing and Grubbing, Construction Surveying, and Mobilization. Typical notes instruct the Contractor as to how the HBP quantities were calculated, incidental items of work, tack coat application requirements, ROW access restrictions, pavement smoothness requirements, the type of compaction required, and items of work that are not listed on other plan sheets.

Use Plan Sheets #3 , General Notes, and answer the questions:

3-1 What is the type of compaction to be used for this project? 3-2 What is the smoothness category for concrete pavement to be used on the project? 3-3 How many sanitary facilities will be required?

CHAPTER 4: SUMMARY OF APPROXIMATE QUANTITIES &

TABULATION DRAWINGS

SUMMARY OF APPROXIMATE QUANTITIES

The Summary of Approximate Quantities plan sheet shows all the pay items of work that are included in the Contract. The items are listed in numerical order by item code. Use Plan Sheet #4 to answer the questions:

4-1 How many square feet of Sign Panel (Class I) is estimated to be required? 4-2 How many total linear feet of Fence Chain Link (Special) (36 inch) is needed? 4-3 How many linear feet of 2 inch Electrical Conduit is required for Structure #F-15-DJ?

TABULATION DRAWINGS

Tabulation drawings are used to tabulate specific pay items in regard to location and offset. They are included in most project plans. All pay items must be either mentioned in a general note or have a tabulation somewhere in the plans. A single tabulation normally includes similar items. For example, a tabulation may list all locations of curb & gutter, sidewalk, and curb ramps for the project.

Structure Quantities

The structure quantities sheet tabulates the minor structures such as culverts, inlets, other drainage structures, and associated structure excavation and backfill. This sheet is sometimes called the Tabulation of Drainage Items and is normally on its own sheet in a set of plans.

Surfacing

The surfacing tabulation contains the quantities of various materials to be utilized in the pavement structure and is also normally on its own sheet of the plans.

Fence, Guardrail, Delineator

The fence, guardrail and delineator tabulations are frequently combined onto one sheet of the plans.

Removals and Resets

Removals and Resets are normally included in the individual tabulations for that item of work. For example, pipe removals may be included on the Structure Quantities sheet and guardrail removals are included in the Guardrail Tabulation. However, sometimes all or most removals and resets are combined into one sheet.

Use Plan Sheets #5 and #6 to answer the questions:

4-4 How many square yards of Concrete Pavement (10 inch) is required between Sta. 116+50 and Sta. 119+50 Rt.? 4-5 What length of 24 inch culvert pipe is required at Station 85+00 Lt.? 4-6 What type of embankment protector is required at Station 114+48 Lt on the Kennedy Gulch Access Road?

CROSS SECTION

As you face the front of the chair, a section has been sliced away. Here the chair was sliced across the seat. You see the layers of the cushion and seat inside the seat. The rest of the chair, shown by dotted lines, is behind the point where the slice was made.

LONGITUDINAL CROSS SECTION

As you face the side of the chair, a section has been sliced away. You see the inside of the seat from the side. Also note the inside of the crosspieces at the top and bottom of the chair.

PROFILE VIEW

A Profile View is a lot like a longitudinal cross section of the roadway. Rather than left to right, the profile view shows the hills & valleys of the roadway running along the centerline of the road. It’s how the road would look if you were actually riding on the surface of the road. (Profile view will be further discussed in another chapter.)

5-1 Below is a drawing of an old boat. Five of the six views mentioned previously, are shown on it. Write the name of the view above each drawing.

Of course, the actual views on a set of plans also give dimensions, materials used in construction, and many other construction details.

The ELEVATIONS generally show the items from the OUTSIDE. These views are usually very clear drawings, almost like a picture.

The CROSS SECTIONS always show an inside view where something has been sliced away to show you how the inside part should be. These slices may be made at any point and would be compared to cutting an apple into two parts with a knife. The next pages show you how you can sometimes tell where the section is or where the cut was made.

Suppose, for example, sections of a pencil were used to show the inside materials at different places along the length. See how this is shown in the drawing. The lines between the letters A-A, B-B, and C-C show where the section is taken. The arrows on the ends of the lines show which way you’re looking toward when you look at the section.

The sections are labeled, A-A, B-B, and C-C, etc., to correspond with the letters on the overall diagram, as shown here:

If there was a project for this road in the past, the beginning station number may be much higher than the previous example.

Since all items on the plan refer to the Survey Center Line, any particular item can be located by giving its stationing and the perpendicular distance left or right of the Survey Line. The length of the project may be arrived at by subtracting the beginning station from the ending station (making allowances for equations) and multiplying by one hundred. An explanation of equations will follow.

For instance, if a project begins at station 650 (written 650+00) and ends at station 920 (written 920+00), the length is (920-650) X 100 = 27,000 feet. This can easily be converted to miles by dividing by 5280 feet per mile.

Just as 12 inches make one foot, 100 feet make one station. It is 100 feet from Station 100 to Station 101 or from Sta. 493 to Sta. 494, etc. (see the following)

Answer the question:

6-1 How many feet make up a station?

A half station is 50 feet and is located halfway between stations. It is written as +50 after the station number. The example below shows you how station numbers and half stations are written.

Any point between two stations is shown in this same way:

For example, two feet ahead of station 500+00 is written as 500+02. Numbers less than 10 are indicated as 01, 02, 03, etc. Ninety-nine feet ahead of station 500+00 is written as 500+99. Of course, 100 feet ahead of Sta. 500+00 is Sta. 501+00.

In other words, to show that a point is exactly on a station, write it as +00. To find the distance between any two stations (except where station equations or equalities are involved) simply subtract the lower station from the higher one, ignoring the plus sign. You will get the answer in feet.

Example: To find the distance from the Station 2060 20+60 to Station 12+80 you can - write the numbers like this: 780

It is 780 feet from Station 20+60 to Station 12+80.

6-2 The distance between Station 48+76.2 and Station 51+24.8 is ________ feet. 6-3 The distance from Station 14+10 to 15+00 is ________ feet 6-4 The distance from Station 80+10 to 85+20 is _________feet

On the Plan Sheets, the Station Numbers are usually written along the Survey Line. Stationing is sometimes along a baseline, or along one lane of a multiple lane highway. On a project, AHEAD means in the direction in which Station Numbers increase. (Usually toward the END of a project) BACK means in the direction in which Station Numbers decrease. (Usually towards the BEGINNING of the project).

On a plan sheet, stationing would be similar to that shown above.

Answer the questions:

6-5 What is the Station Number of a point on Survey C/L 50 feet AHEAD of Station 412+00? 6-6 What is the Station Number of a point 50 feet BACK of Station 412+00?

Generally, station numbers progress (increase) from WEST to EAST or from SOUTH to NORTH. Since highways curve and change direction, the above statement is not always true on any one segment of the road. Just remember that when you say AHEAD you mean toward a higher or up station. When you say BACK, you mean toward a lower or down station.

STATION EQUATIONS

Sometimes it is necessary to relate a system of stationing to another system as the connection between two projects or to account for an increase or decrease in the projects length due to a change in horizontal alignment.

CHAPTER 7: PLAN AND PROFILE SHEETS

Roadway Plan Sheets depict all details of the project horizontal alignment. They may be presented in conjunction with the corresponding profile on the lower half of the sheet called a Plan/Profile Sheet, or the Profile Plan Sheets may be a separate sheet from the Plan Sheet.

Existing features and roadway design elements such as pavement and shoulder widths, medians, curbs, drainage elements, tapers, turning provisions, and intersecting roadways are shown on these sheets. All horizontal geometry is depicted and labeled to fully define the design intent. Separate Plan Sheets may be required for details, which cannot be adequately shown on the Roadway Plan Sheets.

Both separate Plan & Profile Sheets and combination Plan/Profile Sheets give a view of the entire project. They both begin with the lowest station number and the beginning of the project and show the entire roadway ahead to the end of the project.

PLAN VIEW

Remember that a PLAN VIEW shows the roadway as if you were flying high over the project and were looking down. Turn to Plan Sheet #7. On this Plan Sheet, the PAVEMENT LINES (edges of the pavement) are shown. You can also see the SURVEY CENTER LINE running from the left of the sheet AHEAD to the right of the sheet, then continuing on to the next plan sheet. Above survey C/L, on the Plan Sheet, is considered left of the Survey Line. Below the survey C/L is considered right of the Survey Line. Either case will be as though you were standing on the Survey Line facing ahead.

Remember that throughout this course and when speaking of plans that LEFT refers to left of the Survey C/L and RIGHT refers to the right of the Survey C/L, as shown in the previous drawing, not the left and right side of the Plan Sheet.

On all construction plans and right of way plans, there is an arrow-like symbol with the point indicating North.

The direction of all control and boundary lines is in reference to this North arrow.

The direction of a Survey Center Line as you are advancing in stationing, as expressed by a bearing, defines the relationship between the direction of the survey line and a North-South line. It is customary to orient drawings so that the North direction is to the

TOP of the plan. However, since plans for a complete highway project can seldom be confined to a single sheet, and must be a series of sheets, it is an accepted practice to make the plans to extend from left to right without regard to the North direction. Look again at Plan Sheet #7 and see the NORTH ARROW. Remember that Station Numbers normally increase from SOUTH to NORTH. On this plan sheet, the stations “65”, “70” and “75” are shown above the centerline. Note the 100-foot tick marks on the survey line indicating intermediate stations between the larger 500-foot tick marks.

HORIZONTAL ALIGNMENT

Horizontal Alignment consists of tangents and curves and is shown on the Plan View. Plan Sheet #7 shows the Horizontal Alignment. Plan Sheet #8 shows the Vertical Alignment or Profile View of the same section of roadway. (Vertical Alignment will be discussed more later.)

Tangent: A straight segment of roadway

Curve: Segment of roadway joining two tangent segments

Point of Curve (PC): The beginning of a curved segment of roadway coming from a tangent.

Point of Tangent (PT): The point at the beginning of a tangent section of roadway coming from a curve

Point of intersection (PI): The point where 2 tangents intersect

Point on Tangent (POT): A point on a tangent (straight) segment of roadway

Point on Curve (POC): A point on a curved segment of roadway

Point of Tangent to Spiral (T.S.): The beginning of the spiral curve segment of roadway coming from the tangent.

Point of Spiral to Tangent (S.T.): The point at the beginning of a tangent section of roadway coming from a spiral curve

Point of Spiral to Curve (S.C.): The point at the beginning of the curve coming from a spiral curve.

Point of Curve to Spiral (C.S.): The point at the beginning of the spiral coming from a curve.