Device for bridging expansion joints in bridges or the like

A device for bridging expansion joints in bridges or the like is provided with parallel lamellae arranged at right angles to the longitudinal axis of the traffic route. The lamellae are supported on at least two inclined traverses which are pivoted and movably supported at both sides in the joint edges, which bridge said joint diagonally with respect to the longitudinal axis, and are rotatably and movably guided in sliding drag bearings at the bottoms of the lamellae. The inclined traverses are arranged parallel to each other, whereby the support width of the lamellae is always uniform. At least one longitudinal traverse which is movably connected the longitudinal direction with each lamellae via sliding bearings fixed at the bottoms of the lamellae is provided for, preferably at the edge, for taking up the forces which inevitably occur due to movements of the bridge superstructure.

FIELD OF THE INVENTION 
The invention relates to a device for bridging expansion joints in bridges 
or the like, said device comprising lamellae extending at right angles to 
the longitudinal axis of the traffic route and being supported on 
traverses which are pivoted and/or movably supported in the joint edges 
and bridge the joints. 
BACKGROUND OF THE INVENTION 
The prior art as disclosed in German Patent Document No. DE 27 46 490 C3 
discloses a bridging device for expansion joints in which lamellae 
extending at right angles to the longitudinal axis of the traffic route 
are supported on traverses which are pivoted and movably supported at both 
sides in the joint edges and which diagonally bridge the joint. U-shaped 
bows are welded to the bottom of the lamellae, wherein elastic sliding 
drag bearings which are slewably connected with the lamellae and in which 
the traverses are movably guided are arranged in said U-shaped bows. In 
order to take up the horizontal force components occurring in the lamellae 
during the movement of the bridge superstructure, the traverses are 
alternately diagonal to each other. Thereby, the force components of the 
horizontal forces which are directed in the longitudinal direction of the 
lamellae neutralize each other so that there is no danger of a one-sided 
drifting of the lamellae. 
The fact that the support distances of the lamellae are not uniform in this 
known construction has proven to be a particular disadvantage. As a 
result, a complicated reinforcement of the lamellae is required at those 
places in which the distances are larger in order to ensure the required 
flexural strength for loads occurring, for example, in heavy vehicle 
traffic. If the superstructure moves due to temperature influences, such 
as a creeping or contraction of the concrete, the traverses twist about a 
vertical axis. Due to the swivel, and traverses being arranged at an acute 
angle to the direction of movement of the superstructure, the angle 
between the swivel traverse and the direction of the lamellae or the two 
joint edges, respectively, changes when the joint gap is increased or 
reduced in size. 
SUMMARY OF THE INVENTION 
It is, therefore, the main object of the present invention to provide for a 
device of a simple design for bridging expansion joints, wherein the 
lamellae are supported by the traverses at uniform distances and the force 
components resulting from the movements of the superstructure as well as 
from the traffic loads are securely taken up. 
According to the present invention, the object is solved by a device 
comprising the features of claim 1. 
According to the present invention, the control forces are transmitted via 
the diagonal inclined traverses if there is a change in the joint width. 
The parallel arrangement of the inclined traverses therein guarantees a 
uniform support distance, so that a reinforcement of the lamellae is not 
required. Horizontal control forces which result from movements of the 
bridge superstructure generate force components in the longitudinal 
direction of the lamellae due to the parallel arrangement of the inclined 
traverses. Said force components are taken up by at least one additional 
traverse in the form of a guide traverse which is preferably disposed at 
the edges and may be arranged in the direction of displacement of the 
superstructure or diagonally, in particular opposite to the direction of 
the inclined traverses. 
The guide traverse may therein also have the function of a moulding 
traverse which is required as a vertical support for the lamellae at both 
ends of the joint construction and which constitutes a guide for the 
lamella ends, so that the lamella ends are prevented from being vertically 
displaced to the upside. 
An additional control mechanism is provided for ensuring that the lamellae 
do not jam at their protruding ends with which they are supported on the 
guide traverse, wherein the control forces of said control mechanism 
counteract the frictional forces resulting from the lamellae control force 
components acting in the longitudinal direction of the lamellae. This 
control mechanism may consist in advantageous manner of elastic control 
springs disposed in the area of the guide traverse or guide traverses, 
respectively. The control forces are therein arranged laterally between 
the lamellae and counteract the frictional forces. The control mechanism, 
however, can also consist of a rod control. 
If there are not any additional control forces acting on the protruding 
lamella ends supported on the guide traverse, it is suitable to design the 
protruding lamella ends in such a manner that they are horizontally 
resistant to bending, as otherwise a horizontal deflection of the lamellae 
and thus a jamming of the guide traverse might occur. However, it is 
advantageous to provide for additional guide means at the lateral faces of 
the guide traverse as well as at the protruding lamella ends, wherein such 
guides may be in the form of thrust sliding bearings which are arranged in 
a U-shaped bow at the bottom of the respective lamella at both sides of 
the guide traverse. In order to improve the sliding behaviour between the 
thrust sliding bearing and the guide traverse, the side faces thereof are 
provided with sliding layers which may, for example, consist of sheet 
steel. The contact surfaces of the thrust sliding bearings may furthermore 
be coated with PTFE. Due to the additional thrust bearings, considerable 
forces which act in particular in the case of large road widths in the 
longitudinal direction of the joints and which are not taken up by the 
inclined traverses are securely taken up by the guide traverse. In the 
case of very large joint lengths and due to the alternating directions of 
the longitudinal forces, it may also be advantageous to provide for a 
second guide traverse at the opposite road edge so that smaller forces are 
transmitted to the guide traverse. In this case, it may prove to be 
advantageous that the thrust sliding bearings are only provided for on the 
outside of the guide traverse. 
In order to ensure that the forces distribute evenly into the lamellae and 
are taken up by the guide traverse when the superstructure is moved, at 
least one thrust sliding bearing is provided for each support point 
lamella/guide traverse. Furthermore, a means preventing vertical 
displacement of the protruding end of the lamella is arranged between the 
guide traverse and the respective lamella. This means can consist of 
sliding bearings arranged at the top and the bottom of the guide traverse 
in a bow underneath the lamella, in particular a thrust sliding bearing 
the top of which is provided with the guide traverse and the bottom with 
encompassing guide ledges in such manner that the support in connection 
with the guide traverse prevents the lamella from lifting upwards. 
As was mentioned earlier, such means may be provided at the two opposing 
sides of the protruding lamella ends, but it is also possible to provide 
for a guide traverse on one edge side and for a moulding traverse on the 
opposing edge side, both preventing the lamella ends from lifting in a 
vertical direction when they are designed as described.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
According to FIGS. 1a to c, four lamellae 3 are arranged between the joint 
edges 1, 2 in the direction of the joint, i.e. the transverse direction, 
for bridging a joint. Whereas the joint edge 1 is defined by the bridge, 
the joint edge profile 2 defines the stationary abutment. The lamellae 3 
are supported on a series of inclined traverses 4, 5, 6 which are parallel 
to each other and only three of which have been shown for reasons of 
clarity, as well as an edge-side guide traverse 7 arranged in the 
direction of movement of the superstructure 1, i.e. at right angles to the 
lamellae 3. 
The lamellae 3 are supported via sliding drag bearings 8 on the inclined 
traverses 4, 5, 6 which for their part are supported in recesses of the 
joint edges via sliding drag bearings 9. The lower ends according to FIG. 
1a of the inclined traverses 4, 5, 6 as well as the guide traverse 7 are 
fixed in the edge profile 2 by way of drag bearings 10. As the direction 
of the guide traverse 7 corresponds to the direction of movement 11 of the 
superstructure 1, it is also possible to use a simpler, rigid bearing 
instead of the drag bearing 10. 
In the area of the guide traverse 7, control springs 12 are arranged in 
gaps between the lamellae 3 and between the lamellae and the joint edges 
for ensuring that a uniform lamellae distance is set even in the area of 
the guide traverse when there is a change in the joint width. These 
control springs are in the form of pressure springs and consist of 
polyurethane foam or a similar material. The spring design according to 
FIG. 7, i.e. in the form of a dual seal tube 32 having an inside ribbing 
33 and being made of a material such as chloroprene, wherein the spring 
exerts spring forces due to the folding mechanism of the tube wall and the 
inside ribbing, has proven to be especially suitable. Due to the variable 
length of said tube spring 32, the spring forces can be adapted to the 
respective requirements. In the remaining area of the joint, the control 
forces for displacing the lamellae are generated by the diagonal inclined 
traverses, so that no elastic control elements are required for this 
purpose. The edge-side control springs 12 thus only serve for adjusting 
the lamellae in the area of the guide traverse 7 in order to prevent the 
protruding lamella ends from bending in this area due to control 
movements. 
The adjustment of the lamellae in the case of a change of the joint width 
can be seen from FIGS. 1a to c. Since the pivots of the sliding drag 
bearing 8 relative to the lamellae are fixed, a change of the joint width 
inevitably results in an avertence or displacement of the inclined 
traverses 4, 5, 6 relative to the lamellae 3 which are always parallel to 
each other as well as in a displacement on the guide traverse 7. 
As can furthermore be clearly seen from FIGS. 1a to c, the angle of the 
inclined traverses which for their part remain parallel to each other 
during a movement of the superstructure 1 relative to the lamellae 
changes, so that in the longitudinal direction of each laella a control 
force is generated which has to be taken up at the guide traverse 7. These 
relations are shown for a guide traverse 7 in FIG. 2, in which the guide 
traverse means is parallel to the direction of movement 11 of the 
superstructure 1. Therein, the slewable support of the lamellae on the 
guide traverse or guide traverses, respectively, in the joint edges can be 
dispensed with. If the course of the guide traverse means differs from the 
direction of movement of the superstructure 1, the lamellae must be 
slewably supported on the guide traverse and the guide traverse itself 
must be rotatably guided in both joint edges. The advantage of this 
arrangement is in the lamella and guide traverse supports being prevented 
from jamming in the event of additional joint movements. Control forces 
are generated at the lamella or support points, respectively, during joint 
movements. 
In the above two cases of the parallel arrangement of the guide traverse 7 
or the diagonal arrangement of the guide traverse 7, respectively, the 
lamellae are guided via thrust sliding bearings 13 (see FIG. 3) or 14 (see 
FIG. 6), respectively, which are laterally supported at the guide traverse 
7 for taking up the reaction forces occurring at the inclined traverse 
supports 8 and acting in the longitudinal direction of the lamellae 3. In 
order to obtain a component acting in the direction of control from these 
reaction forces directed at right angles to the guide traverse 7, the 
guide traverse 7 may--as described above--be arranged diagonally opposite 
to the inclined traverses 4, 5, 6. However, the guide traverse may 
basically also be arranged parallel to the inclined traverses, wherein an 
additional control mechanism (such as an elastic control or a rod control) 
must be provided for in the area of the guide traverse, the control forces 
of said control mechanism overcoming the forces of the guide traverse 
acting in the opposite, "wrong" direction. In this case, it would even be 
possible to arrange all inclined traverses and the guide traverse parallel 
to each other. 
In order to prevent the protruding ends of the lamellae 3 from being bent 
upwards in a vertical direction, an arrangement described with reference 
to FIG. 5 is preferred, wherein the free ends of the lamellae are fixed in 
a moulding traverse 15 which simultaneously acts as a guide traverse. As 
can be seen, the free end of the lamella is provided with a stop 16 
comprising a thrust sliding bearing 17 having an elastomer part 18 and a 
steel profile 19 having guide ledges 20, 21 attached thereto. The steel 
profile and the guide ledges are provided with sliding layers of PTFE 22 
on the sliding surfaces thereof opposing the moulding traverse. The 
opposing flank of the guide traverse is also provided with a thrust 
sliding bearing 23. The tensile or compressive forces resulting from the 
control forces and acting in the longitudinal direction of the lamellae 
are transmitted into the guide traverse via such thrust sliding bearings. 
The guide ledges 20, 21 at the same time prevent a vertical displacement 
of the lamellae to the upside. The same arrangement may be provided for on 
the opposing sides of the lamellae but it is sufficient if the control 
forces are only taken up on one side of the bridging construction by way 
of a guide traverse. Therefore, the embodiment according to FIG. 5 is 
provided with a moulding traverse 24 which per se is known and which 
reaches through a disk 25 arranged at the bottom of the lamella 3. 
An alternative embodiment is shown in FIG. 6, wherein a U-profile 26 in 
which the sliding drag bearing 8 or the thrust sliding bearing 14, 
respectively, are arranged is provided for below the lamella 3. It can 
furthermore be taken from FIG. 6 that the bottoms and the tops of the 
inclined traverses are movably guided between the grooves of a lower and 
an upper bearing body 8. Such bearing bodies comprise essentially 
disk-shaped projections which are pivoted in corresponding recesses at the 
lamella or the bow bottom, respectively. The sliding drag bearings are 
inserted in a vertically pre-stressed condition in order to prevent the 
traverses from lifting off the bearings. The inclined traverses are 
supported with sliding drag bearings in the traverse boxes in the same 
manner and their ends comprise stops in order to prevent them from sliding 
out of their bearings at the joint edges. 
In the alternative embodiment shown in FIG. 6, the bottom 27 and the top 28 
of the guide traverse 7 are guided between square bearing plates into 
which corresponding grooves have been milled. These bearing plates can 
additionally be pivoted--as in the case of the sliding drag bearings--with 
the aid of disk-shaped cams 29 at the lamella bottom or bow bottom, 
respectively, if the guide traverse 7 does not extend in the direction of 
movement of the superstructure. If it is arranged in the direction of 
movement of the superstructure, a rotatable support can be dispensed with 
altogether as the guide traverse 7 does not undergo any rotations relative 
to the lamella. The embodiment shown includes a guide traverse 7 which is 
diagonal to the direction of movement of the bridge superstructure 1. It 
can also be seen from FIG. 6 that the thrust sliding bearings 14 between 
which the two side faces 30 of the guide traverse 7 are guided without 
play is provided with sliding foil 31 for reducing the friction. 
Due to the fact that the lamellae are guided at the guide traverse 7 
through the thrust sliding bearing 14, large tensile and compressive 
forces acting in the longitudinal direction of the lamellae can be 
received, which is necessary as all forces introduced via the inclined 
traverses, acting in the longitudinal direction of the lamellae and 
inevitably occurring as a result of the horizontal wheel loads from the 
traffic or during movements of the superstructure due to the diagonal 
arrangement of the inclined traverses have to be taken up by the guide 
traverse. Therefore, the cross-section of the guide traverse is also 
adapted to the lateral loads. A corresponding, sufficiently dimensioned 
reception with laterally guided sliding bearings is provided for both ends 
of the guide traverse in the traverse boxes. 
The above arrangement of the inclined traverses and the guide traverse or 
guide traverses, respectively, proves to be advantageous in so far as the 
support widths of the parallel lamellae are constant in the trafficable 
area. The reinforcement of individual lamellae having enlarged support 
widths which has been required so far in the swivel traverse solution can 
be dispensed with. The possibility of arranging the inclined traverses in 
a more acute angle relative to the lamella results in an improvement of 
the control behaviour. In the alternately diagonal arrangement of the 
traverses relative to the lamellae, the acute angle is limited due to the 
support width of the lamellae varying considerably in the event of an 
increasing inclination of two neighbouring traverses in this traverse 
field. There is no such limitation in the case of a parallel arrangement 
of the inclined traverses. If the joint edge moves in such manner that the 
joint is closing, control forces are generated at the support points of 
the lamellae on the traverses due to the avertence of the traverses about 
a pivot arranged, for example, in a joint edge and having a vertical axis 
of rotation, said control forces displacing the lamellae towards the 
closing direction of the joint on the traverses. These forces are 
counteracted by frictional forces between the lateral steps of the sliding 
bearing and the lateral wall of the inclined traverses.