JPH0380202B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a method of constructing an arch ring for an RC arch bridge.

[Prior art]

Conventionally, when constructing an arch ring for an RC arch bridge, if it is not possible to assemble and install ground-type shoring below the arch ring, an arch center is erected between the arch abutments, and then the arch center is placed above the arch center. The method used was to erect formwork and then pour concrete to form an arch ring. Another method has been to form an arch ring by dividing the arch ring using the cantilever method and pouring concrete from the base of the arch ring toward the arch crown.

[Problem that the invention seeks to solve]

However, in the case of the method using the arch center, the construction cost increases as the arch span increases, so recently, the cantilever construction method has become mainstream.

The cantilever construction method is an application of the bridge girder construction method, and does not require a large arch center, but uses a small-scale mobile work vehicle to construct the arch ring in sections. This has the advantage that costs can be reduced.

However, when using the cantilever construction method, the bridge girder is a nearly horizontal member, whereas the arch ring is a curved member.
When constructing parts from the base of the arch ring to the arch crown, the angle of inclination of the members changes, and the mobile work vehicle must have the ability to handle this change in angle of inclination. There is a problem in that the work vehicle cannot be used as is for the cantilever construction method.

FIG. 11 shows an example of a conventional mobile work vehicle 8 used in the construction of bridge girders, in which front wheels 12 and rear wheels are mounted on rails 10 fixed to the upper part of the bridge girder, front wheels 12 attached to a movable frame 11, Wheels 13 are mounted, and an anchor jack 14 that engages with the lower surface of the head of the rail 10 is attached to the rear of the moving frame 11, and a screw jack 15 that faces the upper surface of the head of the rail 10 is attached. furthermore, front wheels 1 are attached to the moving frame 11.
The main jack 16 is engaged with the rail 10 near 2
, an upper formwork receiving member 17 , a lower formwork receiving member 18 , and scaffolds 19 , 20 are attached, and a swinging lever for moving the mobile work vehicle 8 forward is attached to the rear portion of the moving frame 11 . A small-sized traction device 21 such as a type traction device or a chain block is locked, and the chain 2 of the small-sized traction device 21 is
2 is engaged with the front end of the rail 10, and by manually operating the small traction device 21, the mobile work vehicle 8 is moved forward.

Moreover, FIG. 12 shows a part of the mobile work vehicle 23 modified for arch ring construction, and shows a large propulsion vehicle for pushing the mobile work vehicle 23 up along the arch ring of a steep slope vehicle. Jyatsuki 24
and an angle adjustment device 25 consisting of a screw type telescopic device.

Therefore, the manufacturing cost of the mobile work vehicle 23 shown in FIG. 12 is considerably higher than that of the mobile work vehicle 8 shown in FIG. 11.

Furthermore, when constructing an inclined concrete member, reinforcement work and concrete pouring work must be performed on the slope, so there is a problem that the workability is extremely poor compared to when constructing a substantially horizontal member.

[Purpose and structure of the invention]

An object of the present invention is to provide an arch ring construction method for an RC arch bridge that solves the problems described above that occur when forming an arch ring using the conventional cantilever construction method. The gist is that an arch abutment 1 and an anchor block 2 are constructed on the foundation ground, a base member 4 of a pin support 3 is fixed to the arch abutment 1, and an arch ring is connected to a movable member 5 of the pin support 3. After constructing the base block 6A in a substantially horizontal state, the arch ring base block 6A is suspended and supported by the anchor block 2 via the first suspension cable 7 so that the second arch ring block can be constructed in a substantially horizontal state. death,
Next, after assembling and installing the mobile work vehicle 8 on the arch ring base block 6A, the second arch ring block 6B connected to the arch ring base block 6A is constructed in a substantially horizontal state, and then the third arch ring is constructed. After the second arch ring block 6B is suspended and supported by the anchor block 2 via the second suspension cable 9 so that the block can be constructed in a substantially horizontal state, the first suspension cable 7 is removed from the arch ring base block 6A. Then, the mobile work vehicle 8 is moved onto the second arch ring block 6B, and the third and subsequent arch ring blocks are constructed in a substantially horizontal state, and the first suspension cable 7 and the second suspension cable 9 are used alternately to construct the new construction. This is an arch ring construction method for an RC arch bridge, which is characterized by alternately carrying out lifting support of arch ring blocks and moving a mobile work vehicle 8.

〔Example〕

Next, the present invention will be explained in detail using illustrated examples.

When constructing an arch ring for an RC arch bridge by carrying out this invention, first, as shown in Figs. 1 and 2, concrete arch abutments 1 and 26 are placed on the foundation ground.
After constructing the arch abutment 1, an end post 27 is constructed on top of the arch abutment 1, and an end post 2 is constructed.
7 and the abutment 26, a pin support 3 is placed in advance at a position that will serve as a support point for the arch ring, and the base member 4 of the pin support 3 is attached to the arch abutment. 1 with anchor bolts 29.

Next, a column type support 30 consisting of a large number of columns and column connecting members is assembled and installed on the foundation ground in front of the arch abutment 1, and an arch ring base block is constructed on top of the column type support 30. A groove-shaped formwork 31 is installed so as to be almost horizontal, reinforcing bars are placed inside the formwork 31, and concrete is poured.

On the other hand, as shown in Figs. 3 to 5, a concrete anchor block 2 is constructed behind the abutment 26, and if necessary, the anchor block 2 is anchored to the ground with a lock anchor 32, and an arch ring is constructed. To prevent floating of an anchor block 2 during lifting. Furthermore, one end of the fixing cable 33 to be embedded and connected to the anchor block 2 is fixed to a reinforcing bar or the like at a predetermined position in advance before concrete pouring of the anchor block 2, and the anchor cable 33 is fixed to the upper part of the end post 27 or the upper deck slab. A temporary strut 34 is installed on top of the temporary strut 34, and on both left and right sides of the top end of the temporary strut 34, the intermediate portion of the first suspension cable 7 is slidably supported. A saddle 36 for slidably supporting the part is fixed.

After the concrete of the arch ring base block has hardened, it is removed from the mold, and then
As shown in the figure, a pair of first suspension cables 7 made of wire ropes or parallel wire strands arranged at intervals in the left and right direction are connected to a center hole jack 38 attached to a connecting fitting 37.
and its center hole jack 38.
The first suspension cable 7 is held by a clamp 39 that is engaged with the hollow piston rod, and the other end of the fixing cable 33 is connected to both left and right sides of the connecting fitting 37, and the first suspension cable 7 is It is fitted into the groove of the saddle 35 and sequentially inserted into the top plate of the hollow arch ring base block 6A and the center hole jack 40, and is suspended by the clamp 41 which is engaged with the hollow piston rod of the center hole jack 40. Grip the cable 7.

Next, using the center hole jack 38 on the anchor block side and the center hole jack 40 on the arch ring base side, lift the arch ring base block 6A so that the second arch ring block can be constructed in a substantially horizontal state. Later,
Each part constituting the mobile work vehicle is lifted onto the arch ring base block 6A from above the upper floor slab 28 using a lifting machine such as a crane, and the mobile work vehicle 8 is assembled on the arch ring base block 6A.

Next, a formwork 31 for the second arch ring block is erected, and after connecting the reinforcing bars placed in the formwork 31 and the reinforcing bars of the arch ring base block 6A, concrete is poured into the formwork 31. do. This poured concrete is transported to the pouring position by a cable crane (not shown) placed above the arch ring.

Next, after the concrete has hardened, it is demolded,
Next, by the same procedure as for the first suspension cable 7, the second suspension cable 9 is stretched between the anchor block 2, the saddle 36 and the second arch ring block 6B, and then the third arch to be constructed is The second arch ring block 6B is lifted together with the arch ring base block 6A by the center hole jacks 38 and 40 until the ring block is in a substantially horizontal state. As a result, the weight of the existing arch ring, the weight of the mobile work vehicle 8, etc. are transferred from the first suspension cable 7 to the second suspension cable 9, and the load is released from the first suspension cable 7. This first suspension cable 7 is used to lift the third arch ring block.

As described above, the third and subsequent arch ring blocks are successively constructed in a substantially horizontal state, and the first and second suspension cables 7 and 9 are used alternately to suspend and support the newly installed arch ring blocks. , construct the arch ring towards the arch crown. Figure 9 shows arch ring block 6A.
This shows the state in which floors 6 to 6 have been constructed.

As the length of the existing arch ring increases,
The bending tensile stress acting on the lower edge of the arch ring increases, and if only the reinforcing bars are placed to accommodate the design load, the tensile stress acting on the reinforcing bars may exceed the allowable value. This case can be dealt with by arranging an out cable (not shown) at the lower edge of the arch ring and tensioning the out cable to apply compressive stress to the lower edge of the arch ring.

When pouring concrete for the arch crown part, after removing the mobile work vehicle, as shown in Figure 10, suspending supports 42 are erected across the arch ring blocks on both sides of the arch crown part. The formwork of the arch crown portion is supported by the shoring 42, reinforcing bars are placed within the formwork, and concrete is poured.

After the arch ring is completed, if the arch base (arch springing) has a fixed structure, the reinforcing bars are made to protrude from the lower ends of the arch abutment 1 and the arch ring 43 without removing the pin support 3, and those reinforcing bars are removed. After joining, concrete is poured between the arch abutment 1 and the arch ring 43, or after the pin support is removed, the arch abutment 1 and the arch ring 43 are connected.
Place reinforcing bars between the bottom edge and pour concrete.

As the block progresses from the arch ring base toward the arch crown, it is necessary to increase the length of the suspension cables 7 and 9. In this case, loosen the clamp 39 and suspend the suspension from the center hole jack 38. The cables 7, 9 are moved, and then the hanging cables 7, 9 are held again by the clamp 39.

〔Effect of the invention〕

According to this invention, after fixing the base member 4 of the pin support 3 to the arch abutment 1 and constructing the arch ring base block 6A connected to the movable member 5 of the pin support 3 in a substantially horizontal state, the second arch ring The anchor block 2 connects the arch ring base block 6 via the first suspension cable 9 so that the block can be constructed in a substantially horizontal state.
After lifting and supporting the arch ring base block 6A, and then assembling and arranging the mobile work vehicle 8 on the arch ring base block 6A, the second arch ring block 6B connected to the arch ring base block 6A is constructed in a substantially horizontal state. Then, the anchor block 2 connects the second arch ring block through the second suspension cable 9 so that the third arch ring block can be constructed in a substantially horizontal state.
After suspending and supporting arch ring block 6B,
The first suspension cable 7 is removed from the arch ring base block 6A, and the mobile work vehicle 8 is moved onto the second arch ring block 6B. Next, the third and subsequent arch ring blocks are constructed in a substantially horizontal state, and the first
Since the suspension cables 7 and the second suspension cables 9 are used alternately to lift and support the newly installed arch ring block, and the mobile work vehicle 8 is moved, each concrete block that makes up the arch ring of the RC arch bridge is always almost always lifted. Construction can be carried out in a horizontal state, so installation and movement of the mobile work vehicle 8, reinforcing work, concrete pouring work, etc. can be performed easily and quickly, and the cost of erecting the arch ring can be reduced. Moreover, as the mobile work vehicle 8, the one used for conventional bridge girder construction can be used as is, so there is no need to modify the conventional mobile work vehicle or manufacture a new special and expensive mobile work vehicle. Therefore, effects such as being economical can be obtained.

[Brief explanation of drawings]

Figures 1 to 10 show one embodiment of the present invention, in which Figure 1 is a vertical cross-sectional side view showing the completed construction preparation of the arch ring base block, and Figure 2 is a pin support for the arch abutment. Fig. 3 is a vertical side view showing the arch ring base block supported by a suspension cable and a mobile work vehicle installed;
Figure 4 is a front view showing the suspension cable supported by the saddle on the temporary support, Figure 5 is its side view, and Figure 6
The figure is a longitudinal side view showing the connection state between the fixing cable and the suspension cable connected to the anchor block, Figure 7 is a plan view thereof, and Figure 8 is a longitudinal section showing the connection state between the arch ring base block and the suspension cable. A side view, FIG. 9 is a longitudinal sectional side view showing a state in the middle of construction of an arch ring, and FIG. 10 is a longitudinal sectional side view showing a state when an arch crown portion is being constructed. 1st
FIG. 1 is a side view showing a conventional mobile work vehicle for constructing bridge girders, and FIG. 12 is a side view showing a conventional mobile work vehicle modified for arch ring construction. In the figure, 1 is an arch abutment, 2 is an anchor block, 3 is a pin support, 4 is a base member, and 5 is a
is a movable member, 6 is an arch ring base block, and 7 is a movable member.
is the first suspension cable, 8 is the mobile work vehicle, 9 is the second suspension cable, 26 is the abutment, 27 is the end post, 28 is the upper floor slab, 29 is the anchor bolt, 30
31 is the formwork, 32 is the lock anchor, 33 is the anchoring cable, 34 is the temporary support, 35
36 is a saddle, 37 is a connecting fitting, 38 is a center hole jack, 39 is a crown, 40 is a center hole jack, 41 is a clamp, 42
is a suspension support, and 43 is an arch ring.

Claims (1)

[Claims] 1 Construct an arch abutment 1 and an anchor block 2 on the foundation ground, fix the base member 4 of the pin support 3 to the arch abutment 1, and approximately After the construction is carried out in a horizontal state, the anchor block 2 is attached to the first arch ring block so that the second arch ring block can be constructed in a substantially horizontal state.
The arch ring base block 6A is suspended and supported via the suspension cable 7, and then the mobile work vehicle 8 is assembled and installed on the arch ring base block 6A. The second arch ring block 6B is suspended by the anchor block 2 via the second suspension cable 9 so that the second arch ring block 6B can be constructed in a substantially horizontal state, and then the third arch ring block can be constructed in a substantially horizontal state. After the upper support, the first suspension cable 7 is removed from the arch ring base block 6A, and the mobile work vehicle 8 is moved onto the second arch ring block 6B, and then the third and subsequent arch ring blocks are placed in a substantially horizontal state. Arch ring construction for an RC arch bridge characterized by alternately performing construction, lifting support of a newly installed arch ring block by alternately using a first suspension cable 7 and a second suspension cable 9, and moving a mobile work vehicle 8. Law.