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CHAPTER 9. USING OTHER LIMITSTATE:RING FEATURES TO INVESTIGATE BRIDGE
BEHAVIOUR
9.3
Modelling bridge spans with intermediate supports
Assessment engineers are sometimes required to analyse a masonry arch bridge which contains spans which have been propped. Whilst such propping is not in general recommended
as a remedial measure, if these are present then LimitState:RING can model the likely effects
of this. For example, suppose that the crown of an arch was propped. This can be modelled by
specifying that one or more blocks at the crown are restrained in the vertical (y) direction. The
failure mechanism is altered accordingly (Figure 9.2).
(a) unpropped failure mechanism
(b) differing failure mechanism when propped
Figure 9.2: Using LimitState:RING to mimic the effect of a midspan prop
c LimitState Ltd