Flashcards in GENERAL PLANS and DETAILS (Not Inc. Grading + SW) Deck (41)

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1

## Layout method for complex angular and curvilinear designs

### Angles, bearings, and arcs

2

## Dimension lines are extended from an object at a ___ angle

### 90 degree

3

## Best pH for most plants

### 6.0 - 7.5

4

## Diameter of a tree 4" or less measured 6" above the ground

### Caliper

5

## Layout Plan: Problem associated with under-dimensioning

### Greater interpretation by the contractor / loss of control of the design

6

## Layout Plan: Problem associated with over-dimensioning

### Greater potential for error or confusion; implies an inflexibility in accommodating field conditions

7

## Hierarchy of Dimensioning

### Fixed dimensions > Semi-fixed dimensions > Flexible dimensions

8

##
Dimension type that locates features w/ high level of accuracy; Usually for legal purposes; Typically located by a licensed land surveyor

Also BASELINES; defines features w/ semi-fixed locations

e.g. property lines, ROW, building locations, setbacks, and other aspects governed by code requirements)

### Fixed dimensions

9

##
Dimension type for points, lines, or planes located by fixed dimensions (baselines)

Used to locate most landscape improvements

### Semi-Fixed Dimensions

10

##
Dimension type used to locate site elements that do not require precision and / or may be adjusted based on field conditions

May uses '+/-' or 'VIF'

### Flexible Dimensions

11

## Dimensions that can be determined only after construction has progressed to a point where an actual measurement can be taken

### Field Dimensions

12

## Level of precision is usually assumed to be:

###
½ of the smallest unit indicated

e.g 84’-3” = +/- ½” precision

When dimensions are provided as a decimal (e.g. 84.25ft, eg) assumed precision is ½ of the lowest decimal point (e.g. .005ft)

Degree of precision should reflect realistic tolerances that can achieved in construction of a particular feature / material

13

## Identifies the distance bw two points

###
Dimension Line

- Should be heavier in weight than dimension lines

- Should not be broken

14

## Extend at a right angle from the dimension line to the object measured

###
Extension Line

Should be lighter in weight than dimension lines

15

## Convention of locating dimension line labels

###
- Above the dimension line

- Read from bottom right hand side of sheet

16

##
Horz. Layout Method:

Used when a considerable % of side elements are orthogonal to the Fixed Features (PL, new / ex. Building, etc)

Baselines (e.g. building walls) serve as reference points from which objects are measured

String / chain dimensions are closely associated w this method

### Perpendicular Offsets

17

##
Horz. Layout Method:

Often used w/ curvilinear elements that do not require a high degree of accuracy

Uses offsets at fixed intervals taken from a baseline to the edge or centerline of an element

Accuracy of the shape is limited by the offset interval

### Baseline System

18

##
Horz. Layout Method:

Distances provided along an X,Y axis to provide unique geographical positions of points from a known POB or PO (point of origin)

### Coordinate System

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##
Horz. Layout Method:

Latitude (N-S); departure (E-W)

Either a bearing angle or a length is provided for ea. Point (but not both)

### Latitude and Departure

20

##
Horz. Layout Method:

Used for the layout of complex curvilinear designs

Bearing: direction of a line specified by a given angle bw the line and an established meridian

Arc: segment of a circle; defined by a center point, a radius and an internal angle; its end points and orientation must be defined

### Angles, Bearings, and Arc

21

##
Horizontal Curve Type:

Two curves in the same direction connected by a tangent; to be avoided in road design

### Broken-back curve

22

##
Horizontal Curve Type:

Single radius; most commonly used for low speed roads

### Simple curve

23

##
Horizontal Curve Type:

Two or more radii in the same direction; difference in the length of the radii should not be more than 50%

### Compound

24

##
Horizontal Curve Type:

Two arcs in opposite directions; usually requires a tangent between them

Length of tangent depends on road’s design speed

### Reverse curve

25

##
Horizontal Curve Type:

Typical curves for high speed roads entail a series of curves with a constantly changing radius

###
Spiral Transitional Curves

(More difficult to calculate and lay out; typically not used by LAs since it is primarily for high speed roads)

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## Marks the beginning of the curve at which the road alignment diverges from the tangent line in the direction of stationing

### Point of Curvature (PC)

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## Marks the end of the curve at which the road alignment returns to a tangent line in the direction of stationing

### Point of Tangency (PT)

28

## Where two tangent lines intersect

### Point of Intersection (PI)

29

## Central angle of the curve; equal to the deflection angle between the tangents

### Included Angle (I)

30