Lecture 5, Tues Feb 13,2018 and Thurs,Feb 15/// Lecture 5 on moodle all Flashcards

1
Q

True or false question that comes in the exam

A

Vertical curve length must be higher than SSD ( Not true because we have the height of the object that we detect)

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2
Q

We want to find the minimum length of the Crest vetical curve

A

Vertical curve length must be higher than SSD ( Not true because we have the height of the object that we detect), That is why we compare with the Sight distance

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3
Q

Minimum Crest curve length

A

Formula is found on slide number 7, We first assume S>L or L

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4
Q

We can use K to find the Minimum length for crest crest crest vertical curves

A

Formula is on page 11

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5
Q

There is a minimum length of the crest vertical curve

A

Lmin is 30-100 m or 0.6 *design speed(km/hr) whichever is bigger

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6
Q

For K > 51 ⇒ drainage may be of concern since

the crest curve is rather flat; very important remember it

A

True

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7
Q

Now we gonna work for the sag vertical curve

A

In daylight, the sight distance is not restricted
on sag vertical curves
• Critical concern here is with the headlight
sight distance at night, or length of road
illuminated by vehicle’s headlights.

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8
Q

The formula for Sag vertical curve is the following; Also note that we can use K

A

check page 24 and 25

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9
Q

There is a minimum length of the sag vertical curve

A

Lmin is 30-100 m or 0.6 *design speed(km/hr) whichever is bigger; it is the same as the crest vertical curve.

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10
Q

Kmax = 51 or else the curve

will be too flat and we will have a drainage problem

A

True

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11
Q

Example 7 is very important

A

true

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12
Q

Passing sight distance is only relevant for crest vertical curves because for sag vertical curves, the upcominng car in the opposite direction can always be seen, also at night u can see the headlights for the carcoming

A

TRue

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13
Q

Minimum curve length to provide for PSD (only for crest remember

A

The formula is found on page 40, also we can use K as in page 41

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14
Q

The lengths of crest vc’s required to provide
for minimum PSD are substantially longer than
those for SSD

A

True

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15
Q

Sag vertical curves and overhead structures

A

Consider sag curves being built under an
overhead structure (mtl tunnel of nahr el kalb)
– Line of sight may be restricted
– Entire curve length may not be visible.

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16
Q

We have minimum curve length to provide enough Stopping Sight Distance (SSD)

A

formula is present on page 51 and check page 52 and read it all

17
Q

PSD is only applicable for 2 lane highway

A

True

18
Q

When dealing with obstacles in sag vertical curves we consider truck

A

because it is more conservative