Supports

TUTORIAL 3

to answer just click on the button or image related to the answer

Question 1 how many reactions can be producedby a fixed support? What are they?

2 – horizontal, verticala

3 – horizontal, vertical, moment b

more c

Question 2

1 - verticala

how many reactions can be producedby a simple support? What are they?

2 – horizontal, vertical b

3 – horizontal, vertical & moment c

Question 3

1 - verticala

how many reactions can be producedby a roller support? (pinned at top)

2 – vertical,

horizontal b

3 – vertical, horizontal,

moment

c

Question 4

1 - verticala

how many reactions can be producedby a pinned (hinged) support? What are they?

2 – vertical, horizontal b

3 – vertical, horizontal,

moment c

Question 5

1 - verticala

2 – vertical, horizontal b

3 – vertical, horizontal, moment c

how many reactions can be producedby the structural system shown? What are they

Question 6 What does structurally determinate mean ?

structure has 3 reactions a

can use just the 3 equations of staticequilibrium to calculate reactions

c

a and b d

b reactions cannot be calculated usingthe 3 equations of static equilibrium alone

a and c e

how many reactions can be producedby the structural system shown? Draw them

Question 7a

1a

2 b

3 c

4 d

simple support

Question 7b is the system?

statically determinatea

statically indeterminate b

a mechanism c

simple support

how many reactions can be producedby the structural system shown? Draw them

Question 8a

1a

2 b

3 c

4 d

pin joints

Question 8b is the system?

statically determinatea

a mechanism c

pin joints

statically indeterminate b

how many reactions can be producedby the structural system shown? Draw them

Question 9a

2 a

4 b

6 c

simply supported

Question 9b

is the system?

statically determinatea

statically indeterminate b

a mechanism c

simply supported

how many reactions can be producedby the structural system shown? Draw them

Question 10a

2 a

3 b

4 c

6 d

Question 10b

is the system?

statically determinatea

statically indeterminate b

a mechanism c

how many reactions can be producedby the structural system shown? Draw them

Question 11a

1a

2 b

3 c

more d

Question 11b is the system?

statically determinatea

statically indeterminate b

a mechanism c

next question

enough !

H

V

M

a fixed support can have 3 reactionshorizontal H, Vertical V and moment M

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try harder

we are talking about a fixed support

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we are talking about just one support

next question

enough !

a simple support can only have 1 reaction - just a vertical, V. If you apply a force horizontally - it moves

V

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we are talking about a simple support

(think what happens if you apply a force horizontally)

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we are talking about a simple support

(think what happens if you apply a force horizontally.Think what happens to the ends. Do they go up –i.e. they rotate?

If they do then there is no moment reaction)

next question

enough !

a roller support can only have 1 reaction - just a vertical, V. If you apply a force horizontally - it moves

and since it is pinned it can’t produce a moment reaction

V

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we are talking about a roller support

(think what happens if you apply a force horizontally what happens if you push someone on roller skates – do they resist?)

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we are talking about a roller support

(think what happens if you apply a force horizontally what happens if you push someone on roller skates – do they resist?

Since it is pinned what happens if you apply a force to a hinge – does it rotate or resist? Think of opening a door)

next question

enough !

a hinged support can only have 2 reactions - a vertical, V. and a horizontal, H

It can’t produce a moment reaction

V

H

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we are talking about a hinged support

(think what happens if you apply a force horizontally can it come off the hinge? What happens if you pull a door?)

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we are talking about a pinned support

(think what happens if you apply a force horizontally can it come off the hinge? What happens if you pull a door?

Since it is pinned what happens if you apply a force to a hinge – does it rotate or resist? Think of opening a door)

next question

enough !

this is a rigid supportRemember Question 1?

VH

V

M

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we are talking about a fixed support

(remember Question 1?) Does it pull out of the wall? Does it spin/rotate?

That’s it exactly. A statically determinate structure is one that can produce exactly 3 reactions.

Statically determinate means just that:You can use the 3 equations of static equilibrium to calculate the reactions

next question

enough !

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that’s part of the story

what would happen if there were 2 reactions, or 4?think of the word ‘determinate’ – what does that mean?

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statically determinate

what would happen if there were 2 reactions, or 4?think of the word ‘determinate’ – what does that mean?

that’s it exactly!

next question

enough !

3 reactions for the rigid support (V, H, M) and 1 for the simple support (V) makes 4 altogether

simple support

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THINK !!

how many reactions can a cantilever produce?how many reactions can a simple support produce?

that’s it exactly!

next question

enough !

more than 3 reactions makes a system statically indeterminate,meaning that the reactions cannot be determined

by the 3 equations of static equilibrium

simple support

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THINK !!

how many equations of static equilibrium are here?therefore what make a system statically determinate?

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THINK !!

what makes a mechanism?(when ‘structure’ cannot provide the necessary reactions)

how many reactions have we got?

that’s it exactly!

next question

enough !

2 reactions (V, H) for each pin jointed support makes 4 altogether

pin joints

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THINK !!

how many reactions can one pin joint produce? how many pin joints are there?

that’s it exactly!

next question

enough !

more than 3 reactions makes a system statically indeterminate.that means the reactions cannot be determined

by the 3 equations of static equilibrium

pin joints

let me try again

let me out of here

THINK !!

how many equations of static equilibrium are here?therefore what make a system statically determinate?

let me try again

let me out of here

THINK !!

what makes a mechanism?(when ‘structure’ cannot provide the necessary reactions)

how many reactions have we got?

that’s it exactly!

next question

enough !

1 reaction (V) for each simple support makes 2 altogether

simply supported

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let me out of here

THINK !!

If you push from the side what happens? Does it resist?Is there anything to prevent the ends from rotating?

So how many reactions can one simple support produce?how many simple supports are there?

that’s it exactly!

next question

enough !

less than 3 reactions makes a system a mechanism.If you push from the side, the beam will move (slide). This is a mechanism

simply supported

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THINK !!

How many reactions do you need to make a system statically determinate?How many reactions do you need to make a system statically indeterminate?

that’s it exactly!

next question

enough !

3 reactions for each rigid joint (V, H, M) makes 6 altogether

let me try again

let me out of here

THINK !!

how many reactions can a rigid support produce?how many rigid supports are there?

that’s it exactly!

next question

enough !

more than 3 reactions makes a system statically indeterminate,meaning that the reactions cannot be determined by just

using the 3 equations of static equilibrium

let me try again

let me out of here

THINK !!

What makes a system a mechanism?How many reactions do you need to make a system statically determinate?

How many reactions do you need to make a system statically indeterminate?

that’s it exactly!

next question

enough !

2 reactions for the pin joint (V, H) and 1 for the roller (V) makes 3 altogether

let me try again

let me out of here

THINK !!

how many reactions can a pin joint produce?how many reactions can a roller support produce?

So how many reactions are there in total?

that’s it exactly!

the END

3 reactions makes a system statically determinate,meaning that the reactions can be determined by just

using the 3 equations of static equilibrium

let me try again

let me out of here

THINK !!

What makes a system a mechanism?How many reactions do you need to make a system statically determinate?

How many reactions do you need to make a system statically indeterminate?