JPH0551725B2 - - Google Patents

Description

Claim 1: A piece comprising a front jib 4 and a front runner 5 and a rear runner 15 rolling on a track comprising two transverse rails 2a, 2b on an already cast bridge part or pier 1. Cast-molded carriage with support structure 3
The two rear runners are equipped with rails 2a and 2b.
Splitting a prestressed concrete bridge using a cantilever construction method in which the rear runner supports a gate-shaped frame, which is arranged so as to cooperate with the lower side of the flange of the rail and to which the rear part 23 of the cast carriage is fixed. In the casting machine, the portal frame has pivot joints 26, 27, 31, 3 at all four corners.
2, the axis of the joint extends in the longitudinal direction of the track 2, and the portal frame can be swung laterally around the axes 26, 27 of the two lower pivot joints. Split casting equipment.

2 Cantilevered structure with a front jib 4 and a front runner 5 and a rear runner 15 rolling on a track including two transverse rails 2a, 2b on an already cast bridge part or pier 1 Casting carriage 3
The two rear runners are equipped with rails 2a and 2b.
Splitting a prestressed concrete bridge using a cantilever construction method in which the rear runner supports a gate-shaped frame, which is arranged so as to cooperate with the lower side of the flange of the rail and to which the rear part 23 of the cast carriage is fixed. In the casting machine, the portal frame has pivot joints 26, 27, 31, 3 at all four corners.
2, and the axis of the joint extends in the longitudinal direction of the track 2, so that the portal frame can be swung laterally about the axes 26, 27 of the two lower pivot joints. The gantry frame has two parallel supports 28, 29 and a top horizontal cross beam 30 whose height is adjustable in relation to the supports, the cross beam 30 carrying the load of the rear runner 15. A split casting device characterized in that it has a suspended tie rod 38 which is secured to the casting bridge deck 18 for greater release.

Description The present invention relates to a carriage of cantilever construction with a front jib and front and rear runners rolling on a track comprising two traversing rails on an already cast bridge section or pier. a cast carriage), the cast carriage having two rear runners arranged to abut the underside of the flange of the rail to cooperate with the rail, to which the rear part of the cast carriage is attached; This invention relates to a split casting device for prestressed concrete bridges using the cantilever construction method in which a portal frame is supported by rear runners.

Casting devices of the above type have been known for some time and are described, for example, in Swedish Patent No. 138855, owned by the applicant. According to the embodiment described in that patent, the anchoring frame between the rear part of the casting carriage and the runner unit is rigid and immovable longitudinally and laterally. There is. The rear part of the casting carriage is fixed to the frame, so
It is also not possible to move the ends of the casting carriage laterally (for example for adjustment purposes). The necessary lateral adjustments must therefore be made directly for each formwork.

The aim of the invention is to simplify the task of lateral adjustment, which is achieved by designing the support frame between the rear part of the casting carriage and the runner as a portal, so that it can be rotated around all four corners. It is constructed by providing joints and extending the joint axes in the longitudinal direction of the track, the support frame being able to swing laterally about the two lower joint axes.

If the support frame containing the rear part of the carriage is moved to one side, the formwork suspended from the front part of the casting carriage will correspondingly move as the casting carriage pivots about the front runner. Moved to the other side. As a result, lateral adjustments of formwork panels can be made easier, more accurately and also more quickly.

Also, when the rear portion of the casting carriage is in the correct position, it is desirable to fix the rear end portion of the casting carriage to the already poured concrete deck in order to fix the position.

Therefore, in the second invention of the present application, the support frame or the portal frame has two parallel vertical supports,
with a horizontal cross beam at the top, adjustable in height in relation to the support, the cross beam being fixed to the cast bridge deck to offload the rear runners. Equipped with a pull-up tie rod. In this case, the front and rear runners do not contact the underside of the traverse rail and the loads acting on the casting carriage are supported by the tension tie rods.

Also, as the load increases, the tension experienced by the tie rods increases, as does the elongation of the tie rods, which eventually becomes considerable, resulting in a significant ``loss'' of the front part of the casting carriage as well as suspension of the formwork. "downward deflection" or decline.

In order to avoid the above-mentioned disadvantages, a preferred embodiment of the invention provides for a tensioning device or jack which is adjustable in height to be installed between the rear part of the casting carriage and the cast part of the concrete bridge; The method used is to stress the tie rods less than the calculated maximum load but 10% more.

In this preferred embodiment, load-induced displacements of the height of the front part of the casting carriage and the formwork are avoided.

To enable a simple method of stressing the tie rod, in a preferred embodiment of the invention:
A height-adjustable tensioning device or jack is provided between the longitudinal girder provided between the parallel supports of the support frame under the rear part of the casting carriage and the top surface of the bridge deck; The tensioning device or jack is preferably equipped with a gauge to indicate the tension force.

The invention will be explained in more detail below by way of example with reference to the attached drawings, in which: FIG.

1 is a partially sectional side view of the device according to the invention and of a part of the bridge that has already been cast; FIG. 2 is a front sectional view of the device and a sectional view of the support bridge in the direction of the arrow - in FIG. 1; , FIG. 3 is an enlarged end sectional view of detail A of FIG. 1 viewed in the direction of the arrow -, and FIG. 4 is an end sectional view similar to FIG. 3 showing another embodiment of the invention. It is.

1 and 2 show a recently cast bridge section 1, such as the top of a pier carrying parallel transverse rails 2. FIG. On the rail runs a casting carriage 3 with a front jib 4 cooperating with the traversing rail 2 and front and rear runners 5 and 15, respectively. A downwardly extending support tie rod 6 is attached to the front end of the front jib 4, and two lower transverse rails 7 are attached to its lower end that extend freely rearward.
are fixed, and the mutual distance between them is considerably smaller than the width of the internal formwork described below (see Figure 2).
The rear part of the traversing rail 7 is rotatably suspended in a bracket 8 with runners 9 so that the traversing rail 7 can move forward together with the carriage 3. The front part of the casting carriage 3 is designated as 22, and the rear part is designated as 23.

The traversing rail 7 supports the inner formwork 11 and the formwork carriage 10. This formwork carriage has runners 14 and can be moved forward and backward on rails 7.

FIG. 2 shows that the bridge section 1 is generally box-shaped, with the side walls and top of the box being cast between an internal formwork 11 and an external formwork 16. These internal forms 11
and external formwork 16 have vertical sections 13, 17 suspended from hangers 20, 21, respectively.
Hanger 20 is supported on formwork carriage 10, while hanger 21 is suspended from casting carriage 3 by tie rods 19.

The inner formwork 11 is carried along the rails 7 and is arranged on said formwork carriage 10 in such a way that it can be moved independently of the outer formwork 16, which is connected to the casting carriage 3 by means of tie rods 19. . No external formwork is shown in FIG.

FIG. 1 shows that a bracket 8 is provided at the front end of the last cast part for the purpose of supporting the rail 7. The necessary reinforcement was carried out at an early stage when there was nothing inside the external and internal formwork, and Figure 1 shows the external formwork 16 (not shown in the first) and the top Internal formwork 11 advanced to overlapping position
The carriage 10 is shown. The formwork components can now be adjusted and prepared for casting the next part. The device shown in FIG. 3 considerably facilitates the work associated with lateral adjustment.

FIG. 3 shows detail A of FIG. 1 from the back (or from the front). As shown in FIGS. 2 and 3, the traverse rail 2 is connected to the anchor unit 34.
It comprises two rails 2a, 2b arranged at a certain distance from each other, which are fixed in advance to the cast bridge deck 18 by means of anchor bolts 35 and anchor bolts 35.

The rear part of the casting carriage 3 comprises a joint unit B, longitudinal beams 33 each fixed to the joint unit B, and a cross member 36.
and horizontal cross beam or end beam 3
0. The cross members 36 extending from each side of the joint unit B are forked as shown to guide the lateral swinging of the supports 28,29. Two support or suspension beams 28, 29 are connected at their lower ends to the trolley yokes 24, 25 for free swinging and are rotatably and at a distance from each other by means of pivot bolts 31, 32. The trolley yoke is suspended from the cross beam 30, and its vertical legs 37 support the aforementioned runners 15, 15a, and 15b at their lower ends, and the trolley yoke has an inverted U-shaped appearance when viewed from the rear. It will be appreciated that the distance between the supports 28, 29 corresponds approximately to the distance between the rails 2a, 2b. Due to the excess weight acting on the front part of the casting carriage 3, the runners 15a, 15b normally roll along the underside of the flanges of the rails 2a, 2b. A tie rod 38 for coupling to the bridge deck 18 depends from the end portion of the crossbeam 30. The tie rod is threaded and includes nuts 39,40.

As can be seen from FIGS. 3 and 4, the supports 28, 29 and the cross beam 30 are connected to the joints 26, 2.
7, 31, and 32 at the four corners. Generally, supports 28, 29 are in their original position, in other words they are approximately vertical as shown in FIG. The supports 28, 29 are under tension due to the weight of the front part 22. The lateral position of the rear part 23 is fixed, if necessary, by means of devices not shown in FIG. When the casting carriage and formwork components are in the position shown in FIG.
position) and approximately the edge of the preceding casting deck. The rear part 23 with the cross beam 30 is displaced laterally by the device shown in FIG. 3, for example from the position shown in FIG. 4 to the position shown in FIG. 3, i.e. to the left as shown in FIG. In this case, the casting carriage rotates about an axis lying at a point between the front runners 5 (see Figure 1), so that the formwork panel in front of the casting carriage moves in the opposite direction, i.e. Move correspondingly to the right. In this way, lateral adjustments can be made quickly and accurately. Once the adjustment is complete, Tie Rod 38
are moved vertically along slots (not shown) in the cross beam 30 as shown in FIG.
5b is removed from the underside of the flanges of the rails 2a, 2b, and the forces acting on the rails and on the supports 28, 29 carrying the trolley yokes 24, 25 are released.

FIG. 4 roughly corresponds to FIG. Under the rear part 23 of the casting carriage 3, more precisely under the longitudinal girder 33, a tensioning device 42 is attached to the bracket 4.
1, said tensioning device extends downwardly to an anchor plate 44 which, in its normal unloaded state, generally acts as a hold-down for the rails 2a, 2b and can also serve as a platform for the device 42. Exists. The tensioning device has a threaded spindle 43 by means of which the tensioning device can rest against the bridge deck 18, so that the tensioning device can be attached to the longitudinal girder 33, i.e. of the casting carriage. It is clamped between the rear part 23 and the bridge deck 18. When tensioning device 42 is locked, tie rod 38
occupies a fixed position between the cross beam 30 and the bridge deck 18. To tension the tie rod 38, a tension jack equipped with a force gauge as shown at 45 is used. Mechanical tension device 4
2, a hydraulic jack with a cylinder and a ram can be used.

The tensioning device 42 is adjusted in height so that the longitudinal girder 33 is generally horizontal. Tie rod 38 is then tensioned to obtain a prestress approximately 10% higher than the effective load. This applied force is applied so that when adjusting and releasing the casting carriage, there is no gradual elongation over time as the casting operation continues, as is the case in the past.
I guarantee that the tie rod 38 growth has already been taken.

The advantage of this design lies in the fact that the downward deflection at the front of the casting carriage 3 is considerably reduced. Furthermore, this provides greater safety against overall damage. As casting continues, the tie rod 38 removes all securing force at the rear; if the tie rod breaks,
The entire carriage tilts forward around the runner 5 and total damage cannot be avoided. They can also be tested by prestressing tie rods. If a break occurs during the prestressing stage, the runner 15, supports 28, 29 and cross beam 30 absorb the load and damage is thus avoided. Prestressing these tie rods increases strength and safety during casting operations.