Titel_SS06

In JCSS (2001) it is suggested to use an exponential probability distribution function to
describe the transient load. The transient live loads may be described by a Poisson spike
process with a mean occurrence rate equal to 1/ and mean duration of days. Hence, the

probability distribution function for the maximum transient live load corresponding to a
reference period T is given by:

v dp

FTFp,maxexp  (^1) p
x 
max
p

(7.13)

The total live load is the sum of the sustained live load and the transient live load. The
maximum total live load corresponding to a reference period T can be assessed as the
maximum of the following two loads:

1,max

2,

Q

Qp

LL L

LLL





(7.14)

where is the maximum sustained live load (reference period 1 year), is the arbitrary

point in time sustained live load,

LQ,max LQ

LP is the arbitrary point in time live load and is the

maximum transient live load (reference period 1 year). It can be assumed that the combined
total live load has a type I extreme value probability distribution function.

LP,max

Wind Loads

Wind loads on structures depend on various factor like wind climate, the exposure of the
building, the shape and dimension of the structure and the dynamic properties of the structure.

In accordance with JCSS (2001) a probabilistic model for wind loads may be defined by:

wcccQ agrref ccQaeref (7.15)

for smaller rigid structures and as:

wcccQ  daeref (7.16)

for more flexible and dynamically sensitive structures and where:

Qref: the reference (mean) velocity pressure

cr: roughness factor

cg: gust factor

ca: aerodynamic shape factor

cd: dynamic factor.

cccer g: exposure factor.

The wind velocity pressure is given by: Q

(^12)
2

QU 1 (7.17)