7/27/2019 viento EXPO2

1/31

7/27/2019 viento EXPO2

2/31

7/27/2019 viento EXPO2

3/31

7/27/2019 viento EXPO2

4/31

7/27/2019 viento EXPO2

5/31

7/27/2019 viento EXPO2

6/31

7/27/2019 viento EXPO2

7/31

Exposure Categories

Exposure A Deleted in ASCE 7-02 and later

Extremely sheltered. Large city centers with tall buildings.

Exposure B

Urban and suburban areas, wooded areas, areas with manyclosely spaced obstructions.

Exposure C

Open terrain with scatter obstructions. Airports, areas thatare generally flat open country.

Exposure D

Flat, unobstructed areas and water surfaces outsidehurricane prone regions. This category includes smooth mudflats, salt flats, and unbroken ice that extend 5,000 ft or 20times the building height in the upwind direction.

See ASCE 7-05 6.5.6 & C6.5.6 (See images!)

A Beginner's Guide to ASCE 7-05

7/27/2019 viento EXPO2

8/31

Determining Exposure

Wind Direction & Sectors (ASCE 7-05

6.5.6.1)

the exposure of the building or structure

shall be determined for the two upwindsectors extending 45o either side of the

selected wind direction.

the exposure resulting in the highest wind

loads shall be used to represent the windsfrom that direction.

A Beginner's Guide to ASCE 7-05

7/27/2019 viento EXPO2

9/31

Location of Pressure

ASCE 7 provides means for computing forces on

various surfaces.

The building envelope surfaces experience pressure

on both sides (i.e. external and internal).

A Beginner's Guide to ASCE 7-05

7/27/2019 viento EXPO2

10/31

Internal Pressure Coefficients,

GCpi

Internal pressure is fairly easy because the air isrelatively stagnant and the shape of the structuredoes not affect its magnitude.

As gusting is not a concern internally, the gust factorand the pressure coefficient are combined. GCpi

The magnitude of the internal pressure coefficient isstrictly dependent on the enclosure classification.

The pressure can be both positive or negative (i.e.suction) depending on the direction of the windrelative to opening for partially enclosed or enclosedbuildings. Both internal pressures must be considered.

See ASCE 7-05 6.5.11.1 & Figure 6-5

A Beginner's Guide to ASCE 7-05

7/27/2019 viento EXPO2

11/31

Internal Pressure

A Beginner's Guide to ASCE 7-05

7/27/2019 viento EXPO2

12/31

Buildings with Roofs Consisting of Flat

Surfaces

ASCE 7-05 Figure 6-6 gives the external

coefficients of wall and roof surfaces.

See ASCE 7-05 Figure 6-6

A Beginner's Guide to ASCE 7-05

7/27/2019 viento EXPO2

13/31

EJEMPLO.- EL EDIFICIO CERRADO QUE SE MUESTRA ES USADOPARA PROPSITOS DE AGRICULTURA, UBICADO EN LA CIUDADDE CHUQUISACA EN UN TERRENO PLANO (SEGN DATOS DESENAMHI LA VELOCIDAD BSICA DEL VIENTO APROX. 90 MPH).

CON EL VIENTO EN LA DIRECCIN QUE SE MUESTRA SE PIDEDETERMINAR LA PRESIN DE DISEO DEL VIENTO QUE ACTA ENLA EDIFICACIN.

7/27/2019 viento EXPO2

14/31

7/27/2019 viento EXPO2

15/31

7/27/2019 viento EXPO2

16/31

7/27/2019 viento EXPO2

17/31

7/27/2019 viento EXPO2

18/31

7/27/2019 viento EXPO2

19/31

7/27/2019 viento EXPO2

20/31

7/27/2019 viento EXPO2

21/31

7/27/2019 viento EXPO2

22/31

7/27/2019 viento EXPO2

23/31

7/27/2019 viento EXPO2

24/31

7/27/2019 viento EXPO2

25/31

7/27/2019 viento EXPO2

26/31

7/27/2019 viento EXPO2

27/31

7/27/2019 viento EXPO2

28/31

7/27/2019 viento EXPO2

29/31

7/27/2019 viento EXPO2

30/31

7/27/2019 viento EXPO2

31/31