Applied Loads and Stability of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 152

These characteristic values should represent shade air temperatures for mean
sea level in an open country with an annual probability exceeding 0.02.
Where an annual probability exceeding 0.02 is deemed inappropriate, the
minimum shade air temperatures and the maximum shade air temperatures
should be modified in accordance with Annex A of EC1 [ 3.3 ]. The values
of minimum and maximum uniform bridge temperature components for
restraining forces shall be derived from the minimum ( T min ) and maximum
( T max ) shade air temperatures. The initial bridge temperature T o at the time
that the structure is restrained may be taken from Annex A of EC1 [ 3.3 ]for
calculating contraction down to the minimum uniform bridge temperature
component and expansion up to the maximum uniform bridge temperature
component. Thus, the characteristic value of the maximum contraction range
of the uniform bridge temperature component

D T N,con should be taken as

D T N , con ¼T o T e : min ð 3 :

22 Þ

and the characteristic value of the maximum expansion range of the uniform
bridge temperature component D T N,exp should be taken as

D T N ,exp ¼T e : max T o ð 3 : 23 Þ

The overall range of the uniform bridge temperature component is
expressed as follows:

D T N ¼T e : max T e : min ð 3 : 24 Þ

For bearings and expansion joints, the National Annex may specify the
maximum expansion range of the uniform bridge temperature component
and the maximum contraction range of the uniform bridge temperature
component, if no other provisions are required. The recommended values
are (

T N,con +20) C, respectively. If the tempera-
ture at which the bearings and expansion joints are set is specified, then
the recommended values are (

T N,exp +20) C and (

D D

T N,con +10) C,
respectively. EC1 [ 3.3 ] states that for the design of bearings and expansion
joints, the values of the coefficient of expansion given in Annex C (Table C.1
of EC1 [ 3.3 ] ) may be modified if alternative values have been verified by
tests or more detailed studies.
According to EC1 [ 3.3 ] , over a prescribed time period, heating and cool-
ing of a bridge deck's upper surface will result in a maximum heating (top
surface warmer) and a maximum cooling (bottom surface warmer) temper-
ature variation. The vertical temperature difference may produce effects
within a structure due to restraint of free curvature due to the form of

T N,exp +10) C and ( D D