Applied Loads and Stability of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 147

3.5.3.6 Collision Forces on Vehicle Restraint Systems
EC1 [ 3.1 ] recommends that horizontal and vertical forces transferred to the
bridge deck by vehicle restraint systems should be taken into account for
structural design. EC1 recommends four classes of values for the transferred
horizontal force as given in Table 3.11 . The horizontal force, acting trans-
versely, may be applied 100 mm below the top of the selected vehicle
restraint system or 1.0 m above the level of the carriageway or footway,
whichever is the lower, and on a line 0.5 m long. The values of the hori-
zontal forces given for the classes A-D derive from measurements during
collision tests on real vehicle restraint systems used for bridges. There is
no direct correlation between these values and performance classes of vehicle
restraint systems. The proposed values depend rather on the stiffness of the
connection between the vehicle restraint system and the curb or the part of
the bridge to which it is connected. A very strong connection leads to the
horizontal force given for class D. A very weak connection may lead to the
horizontal force given for class A. The vertical force acting simultaneously
with the horizontal collision force may be defined in the National Annex.
The recommended values may be taken equal to 0.75 a Q1 Q 1k . The calcula-
tions taking account of horizontal and vertical forces may be replaced, when
possible, by detailing measures (for example, design of reinforcement). The
structure supporting the vehicle parapet should be designed to sustain locally
an accidental load effect corresponding to at least 1.25 times the character-
istic local resistance of vehicle parapet (e.g., resistance of the connection of
the parapet to the structure) and need not be combined with any other var-
iable load.

3.5.3.7 Collision Forces on Structural Members
Vehicle collision forces on unprotected structural members above or beside
the carriageway levels should be taken into account as recommended by
EC1. The code recommends that the forces may act 1.25 m above the

Table 3.11 Four Classes for the Horizontal Force Transferred by
Vehicle Restraint Systems Recommended by EC1 [ 3.1 ]
Recommended Class Horizontal Force (kN)

A 100

B 200

C 400

D 600