34
K. Jurasz-Drozdowska and W. Radomski
zones of damaged girders as well as girders in neighboring spans. Internal forces in
the transom beams also increased, which, however, did not overload these elements.
Not only the impacts on the bottom of the structure can cause the redistribution
of internal forces. All other collisions of means of communication with the bridge
object can contribute to the impact on its work, we are talking here about bridges over
navigable rivers, where there is a risk of the ship being hit by intermediate supports,
as well as the boughs etc. carried by water. Attention should also be paid to the
movement on the site, because in the case of structures with downhill driving (e.g.
arch bridges, truss) there is a risk of collision of cars with the main girder. That is why
it is necessary to properly design equipment components, including energy-intensive
barriers, aimed at preventing this type of failure, because when this happens, it is not
enough to remove damaged vehicles, but also to properly examine the structure to
confirm its ability to continue operation.
3 Computational Models
The article deals with the problem of the impact of sudden damage to the bridge on
its condition and the possibility of further operation. The fictitious three-span bridge
with five main girders has been analyzed (Fig. 4). The structure of the underside of
the structure as a result of the impact of the oversized vehicle in the middle of the
second span has been modeled. Damage in the longitudinal section is distributed as
follows: extreme girder No. 1 damaged over a width of 5 m, successively girder No. 2
over a width of 3.5 m and girder No. 3 over a width of 2 m (Fig. 1). Figure 5 presents
the course and dimensions of damages of individual main beams in transverse view.
The course of the damage line is similar to the one in Fig. 3b. The object was modeled
using the finite element method (FEM) using the SOFiSTiK program as a beam-shell
model (Fig. 1). The bridge was introduced to the program by means of a problemoriented language of CADINP preprocessors in alphanumeric format, introduced in
the TEDDY text editor—this is the basic way to declare data in the system. The
structure was analyzed and calculated for a class B load [12].
The analysis consisted in comparing the results obtained after calculating two
bridge construction systems:
(a) three-span, 5-girder bridge, (output system)
(b) three-span, 5-girder bridge, system with modeled damage, formed in the middle
of the span as a result of impact of an oversized vehicle (damaged system). The
above cases were additionally considered in two variants. The first assumed
a continuous structure, the second with two joints in the middle span. So in
summary, the following cases were considered for a 5-girder structure:
• bridge without damage (marking—m1),
• bridge with damage (marking—m1u),
• bridge without damage, with joints (marking—m2p),
• bridge with damage, with joints (designation—m2pu).
K. Jurasz-Drozdowska and W. Radomski
zones of damaged girders as well as girders in neighboring spans. Internal forces in
the transom beams also increased, which, however, did not overload these elements.
Not only the impacts on the bottom of the structure can cause the redistribution
of internal forces. All other collisions of means of communication with the bridge
object can contribute to the impact on its work, we are talking here about bridges over
navigable rivers, where there is a risk of the ship being hit by intermediate supports,
as well as the boughs etc. carried by water. Attention should also be paid to the
movement on the site, because in the case of structures with downhill driving (e.g.
arch bridges, truss) there is a risk of collision of cars with the main girder. That is why
it is necessary to properly design equipment components, including energy-intensive
barriers, aimed at preventing this type of failure, because when this happens, it is not
enough to remove damaged vehicles, but also to properly examine the structure to
confirm its ability to continue operation.
3 Computational Models
The article deals with the problem of the impact of sudden damage to the bridge on
its condition and the possibility of further operation. The fictitious three-span bridge
with five main girders has been analyzed (Fig. 4). The structure of the underside of
the structure as a result of the impact of the oversized vehicle in the middle of the
second span has been modeled. Damage in the longitudinal section is distributed as
follows: extreme girder No. 1 damaged over a width of 5 m, successively girder No. 2
over a width of 3.5 m and girder No. 3 over a width of 2 m (Fig. 1). Figure 5 presents
the course and dimensions of damages of individual main beams in transverse view.
The course of the damage line is similar to the one in Fig. 3b. The object was modeled
using the finite element method (FEM) using the SOFiSTiK program as a beam-shell
model (Fig. 1). The bridge was introduced to the program by means of a problemoriented language of CADINP preprocessors in alphanumeric format, introduced in
the TEDDY text editor—this is the basic way to declare data in the system. The
structure was analyzed and calculated for a class B load [12].
The analysis consisted in comparing the results obtained after calculating two
bridge construction systems:
(a) three-span, 5-girder bridge, (output system)
(b) three-span, 5-girder bridge, system with modeled damage, formed in the middle
of the span as a result of impact of an oversized vehicle (damaged system). The
above cases were additionally considered in two variants. The first assumed
a continuous structure, the second with two joints in the middle span. So in
summary, the following cases were considered for a 5-girder structure:
• bridge without damage (marking—m1),
• bridge with damage (marking—m1u),
• bridge without damage, with joints (marking—m2p),
• bridge with damage, with joints (designation—m2pu).