Figure $1$ below shows a structure that is to be used as a storage facility in Durban, South Africa. The altitude in the area is $350$ m above mean sea level and the surrounding areas consists of regular cover of vegetation and isolated obstacles with separations of up to $20$ obstacle heights. There are no noticeable features influencing the wind speed in the area and the mean design return period for the structure is $50$ years.Question $1(30$ marks$)$

Figure $1$ below shows a structure that is to be used as a storage facility in Durban, South Africa. The

altitude in the area is $350m$ above mean sea level and the surrounding areas consists of regular cover of

vegetation and isolated obstacles with separations of up to $20$ obstacle heights. There are no noticeable

features influencing the wind speed in the area and the mean design return period for the structure is $50$

years.

Figure $1$

Additional information:

Length of the structure $=25700mm$

Frames are spaced $5000mm$ apart

There is a $40003500mm$ high shutter door on the long side of the structure $($left side of the

above diagram$),$ and a $10002000mm$ high pedestrian door on the front face of the structure.

Determine the:

a$)$ Peak wind pressure

b$)$ Internal and external pressure coefficients on the building for a wind direction of $90$ only.

c$)$ The net wind pressures on the walls and roof of the building

d$)$ Draw a section through the portal frame structure indicating the magnitude and direction of the

possible wind loads acting on one typical internal frame.

Figure $1$

Additional information:

$$

Length of the structure $=25700$ mm

$$

Frames are spaced $5000$ mm apart

$$

There is a $4000$ x $3500$ mm high shutter door on the long side of the structure $($left side of the above diagram$),$ and a $1000$ x $2000$ mm high pedestrian door on the front face of the structure.

Determine the:

a$)$ Peak wind pressure $(8)$

b$)$ Internal and external pressure coefficients on the building for a wind direction of $900$ only. $(10)$

c$)$ The net wind pressures on the walls and roof of the building $(5)$

d$)$ Draw a section through the portal frame structure indicating the magnitude and direction of the possible wind loads acting on one typical internal frame. $(7)$