• Introduction:

In this project we will design a parking umbrella that will fit two cars at the same time; it will be designed such as a truss. This umbrella is used to shade cars in the summer from sunlight or cover cars from rain and snow.

We will design the truss to make it easily assembled on the site and can be easily stored at the storage place as a pre made kit, also minimizing the cost of the truss and its manufacturing. As for designing for Jordan, the truss should be carefully designed to take a high load of snow accumulation.

  • Constrains and Analysis:

- Can cover two regular size cars.

- Can handle accumulation of 30 cm, such that the snow has density of 12% of water.

- Use a design factor of two ( nd = 2 ).

- The weight of the snow is 40% at the top of the truss, 15% at each corner.

- The maximum deflection between the truss and the ground to be 10 cm.

- The clearance between the umbrella and the ground is 210 cm.

- Sixty centimeters of the column length is buried in the ground.

  • Force Analysis:

- When we take the section A-A.

- determine all the reactions and the internal forcesof the beam

If we take the top view: side view:

Loads on the column

We will have failure due to two buckling segment and due to bending

Moment on the C-channel,

  • Selection on the beams:

The beams are pointed as in the figure in numbers in red

assume all are pinned-pinned

- Beam (1):

We selected from table A-17

Thick 40 with outer diameter 41.5 mm

As shown from the iteration table shown at the end of this report.

The factor of safety due to the compression in the beam:

The factor of safety due to buckling:

- Beam (2):

The second beam will be selected as the beam number 1:

The factor of safety due to tension is:

- Beam (3):

The third beam has a compression load so it might fail due to compression or buckling

We can select ( Extra Strong with outer diameter 32.875mm ) but its weight will be higher to choose 41.5mm Thick 40.

Due to compression:

Due to buckling:

- Cable:

In the cable there is only failure due to tension so we selected 16.875 mm Thick 40,

We made this selection due to practical considerations because the bolt will take a lot of the pipe area and might lead to failure due to the holes of the pipe so we chosen this size.

- Column:

We will choose a C-channel with dimensions (152 X 76)

The column as we mentioned before has two segment of failure due to buckling and one due to normal stress from compression and bending moment. Also it can be put in two orientations in each one the moment of inertia and the value of Z will vary changing the stress and the Pcr value so we need to know the best orientation and size for the column.

So in the table of iterations we will see that the only expected mode of failure is due to compression and bending (Normal Stress)

The maximum normal stress:

- Weld mints in the joints:

The weld is shown in brown and in red the projected area of

The weld , so we can approximate it as:

Which can be reached easily in the welding.

The second weld on the same joint:

We can approximate it as:

The weld mint in the column:

First we will calculate the primary and secondary shear

- Weld mint in the in the metal sheet in the corner joint:

- Welding in the head joint:

It can be approximated as a circle

- weld mint in the column which the cable is set:

- The modes of failure from the bolt:

Bearing

Non-threaded:

Threaded:

Tearing:

Take any bolt from standard sizes and substitute in this equations and the lower force must be equal the needed force. For example in the beam which has 0.279F load select 8mm size

But the force needed F = 0.279× 8829 = 2463.3N

So this bolt will use

Defliction in the beam:

from Gastaceliano's theorem: