JPS5980809A - Construction of prestressed concrete floor panel in road bridge - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a construction method for prestressed concrete slabs forming the road surface of road bridges and the like.

In recent years, in addition to the increase in traffic interruptions, the traveling speed and weight of vehicles have increased, and vehicles are susceptible to damage due to the weak points of the road.
Road maintenance is becoming increasingly poor. However, in 1φ steel bridges where two reinforced concrete deck slabs are placed on the steel girders, the tgI2 reinforced concrete deck slabs are often damaged, and as a countermeasure, the new deck slabs are installed with a thickness of 8, and the slab thickness Ct). The Ministry of Construction has issued new guidance on consideration of additional bending moments due to differences in stiffness of main girders, and reinforcement methods. ? Construction work to replace steel or floor slabs is gradually becoming more common. As reinforcement measures for the aging floor slab, G:T, additional longitudinal girders, steel plate adhesion, and fiber reinforcement are being used.In addition, when replacing the floor slab, measures will be taken to minimize traffic restrictions under the current traffic conditions. Therefore, there are two methods: one is to sequentially replace concrete slabs such as well-known composite slabs that have been manufactured in advance at a factory, and the other is to use unit slabs known as semi-prefabricated concrete slabs and place concrete on site. It is being

By the way, as a road bridge other than the above-mentioned steel bridge, there is a so-called concrete bridge made of concrete. In particular, concrete bridges whose girders are made of prestressed concrete are now being used for construction points and spans that were previously considered only for steel bridges. In comparison, there is very little damage and its utility value is increasing.

On the other hand, as a step to apply prestress to the deck of the above-mentioned steel bridge, we used a precast deck, and the main reinforcement direction, that is, the width direction, is ROq construction, and the longitudinal narrowing prestress is applied in the distribution reinforcement direction, that is, the bridge axis direction. There is one that integrates with the main girder by pouring concrete onto the main girder.

However, such a conventional paper does not solve the problem by applying prestress in the direction of the bridge axis of the reinforced concrete slab.
Although the strength and durability of the above-mentioned deck slabs can be improved to some extent, there is a strong desire for new deck slabs with even greater strength and poor durability as llr deck slabs for steel bridges.

The present invention was made in consideration of the above points, and
Prestressed concrete slabs that have been prestressed in advance are used as deck slabs for steel bridges, and the prestressed concrete slabs can significantly improve the strength and durability of steel bridge decks, and also reduce the amount of concrete used. To provide a bridge casting system for prestressed concrete slabs in road bridges, etc., which is easy to use and can also prestress joint concrete in the bridge axis and width directions.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 shows a prestressed concrete floor slab (hereinafter referred to as PS slab) used in the implementation of the present invention. are arranged in the concrete 3 along the width direction and the bridge axis direction, respectively, and one end of the distribution reinforcement 2, that is, the joint flAza, projects from the end surface of the Pa slab A by a predetermined lap length. Further, the PB deck A has a duct for inserting a PC steel material extending in the width direction and the bridge axis direction (two directions), and the PC steel material 4 is arranged inside the width direction duct. The PC steel materials 4 placed in the width direction duct, that is, the PC steel materials 4 placed between the above-mentioned upper and lower main reinforcements 1, are connected to one PC@ placed near both side edges of the PS deck A. kidnapping 4a
, 4a, and the other PC steel members 4 are buried in the concrete 3 in a tensioned state.

In other words, in a precast concrete slab that has ducts in the width and bridge axis directions (two directions), among the PC steel members 4 arranged in the width direction, one of the PC steel members 4 located near both side edges is left, and the other PC steel members [ 4 is tensioned, thereby forming the above-mentioned PB floor slab A.

In addition, the upper i flexible version A has a dimension in which the length 11 in the width direction is longer than the length l in the bridge axis direction, and the bridge axis A hump portion 5 is provided to protrude along the direction. In this hump portion 5, sheaths 6 extending in the bridge axis direction are embedded side by side in the width direction, and the sheaths 6 form the above-mentioned duct for inserting the PC steel material in the bridge axis direction. Further, in the haunch portion 5, cylindrical grout holes 7 are formed which extend in the thickness direction of the P8 deck slab A and are lined up in the bridge axis direction.

On the other hand, 8 in the figure is a glass fiber rain 7 austed concrete plate (referred to as G-R-C! plate and mi!1) attached to PS floor slab A as a formwork for the joint area.
9 shows reinforcing bars of other machines.

Next, an explanation will be given of the inside of the construction 1 in a road bridge or the like using the PS floor sales A configured as described above.

First, as shown in Figures 2 to 4, the steel main girder lO
Seal rubber 1 on both sides of the upper s7 flange 10a in the bridge axis direction.
1 pasted on the above-mentioned PS that has been pre-manufactured at a factory etc.
It will be lowered by a crane above the S floor slab and placed on the main girder 10 above. On the upper 72 inch 10a of this main girder 10,
Dovetails 12 with heads located in the grout holes 7 of the Pa floor slab A are fixed by means such as welding. Therefore, when passing the PEI floor slab A onto the main girder lO, 12 into the grout pole 7 to position the FSS floor slab.

Once the positioning on the upper main girder 10 of one PSS deck slab is completed, the other P8 floor slab A is then lowered by a crane, and a predetermined joint spacing is established between each other on both edges in the width direction of the PSS floor slab, and grouting is performed. A dowel 12 is fitted into the hole 7 and the girder is constructed on the main girder IO. At this time, the joint ends 2a of the distribution bars 2 between the PSS floor slabs are lapped together as shown in detail in FIG. 4.

In this way, the P8 deck slab A is sequentially moved to a section L (20 to 30 m) suitable for introducing prestress in the bridge axis direction.
In addition, these PS floor slabs A
A PC steel material 15 is inserted into the sheath 6 buried in the haunch portion 5 of the PS deck A and each PS floor slab A is joined together.

Next, joint concrete 16 is applied between the mutually facing end surfaces of the PS slab A, that is, at the joints, and after hardening to a predetermined compressive strength, the PC steel concrete 15 is tensioned at the end of the section using a post-tension method. Apply prestress to the bridge axis direction of the deck slab A. At this time, prestress is also introduced into the joint concrete 16 in the bridge axis direction.

Further, prestress is introduced into the unstressed PC steel @ 4a near both widthwise edges of the PS floor slab A using a post-tensioning method, and prestress is applied to the joint concrete 16 at the joint in the widthwise direction. That is, the joint concrete 16 is created by applying prestress to the PC steel members 4a, which are located near both sides of the I'S floor slab A and are not subjected to +A tension.
Prestress is introduced from the stroke of 6. Therefore, prestress is introduced into the joint concrete 16 from the longitudinal and lateral directions in the bridge axis direction and upper width direction.

Finally, mortar grout 17 is applied inside the grout hole 7, and the P8 floor slab A is integrally joined onto the main girder IO. In addition, after introducing prestress into the above-mentioned PC steel materials 4a and 15, grouting is carried out in the duct into which these PC steel materials 4a and 15 are inserted, and the PC steel materials are completely covered with mortar or cement paste to prevent rust. It fulfills its role and at the same time causes an adhesion.

Note that the grout hole 7 is formed in a cylindrical shape, and the seal rubber 11 is pasted on the upper 7 flange lOa of the main girder 10, so that the PS floor slab A can be prevented by these actions when prestress is introduced. to the main girder 10 above the dowel 1
In particular, after the grout hole 7 has been grouted, the mortar grout 17 and dowel 12 are integrated so that the PS
The floating above the S floor plate exerts the effect of preventing the P
It also prevents slippage in the axial and width directions of the SS deck slab.

After completing the erection of the PS deck slab A in the section according to the above-described procedure, the PSS deck slab A is installed on another section using the same procedure as described above to form the road surface of the steel bridge. After the erection of the PB slab A is completed for all sections, concrete is poured on both ends of the PSS slab in the width direction to form the ground cover 20, and the height A21 is attached. Pave the top with asphalt 22 or the like.

For road surfaces such as road bridges constructed in this way,
The use of prestressed concrete deck slabs with the structure described above further increases their strength and durability, making them fully effective for road maintenance on steel bridges, and making the slabs thicker than conventional reinforced concrete deck slabs. It can be made thinner, thus reducing dead weight.

Moreover, since prestress can be introduced into the joint concrete 16 in the bridge axis direction and width direction at the same time as above the PSS deck slab, the weak points of the joint concrete 16 can be covered.

In addition, since the PS floor slabs A are joined together by the lap method using the joint ends 2a of the distribution bars 2, it is possible to easily connect the PS floor slabs A with the same shape by adjusting the width of the joints. It is possible to apply to curved bridges.

Furthermore, in the present invention, the sheath 6 is buried in this part using the haunch part 5, and the prestress is introduced into the hump part 5 by inserting the PC steel material 15 into the sheath 6. Prestress can also be introduced in the bridge axis direction of PS deck slab A if necessary.

As described above, in the present invention, in a precast concrete slab having ducts in the width direction and the bridge axis direction (two directions), the PC steel members placed in the width direction duct are located near both side edges. A prestressed concrete slab was formed by tensioning other PC steel materials, leaving at least one of the PC steel slabs, and the prestressed concrete slab was erected on top of the bridge with a predetermined joint spacing between both edges of the slab in the width direction. After that, the PCC steel is inserted into the duct in the axial direction of the bridge, and after applying joint concrete to the joint and hardening it to a predetermined compressive strength, prestress is introduced in the axial direction of the bridge. This method is characterized by applying prestress to the joint concrete in the bridge axis direction and width direction by introducing prestress into the neighboring prestressing steel members that are not under tension. Compared to conventional concrete, it has more strength and durability, and it is also possible to apply prestress vertically and horizontally to concrete joints. It has a great effect.

[Brief explanation of drawings]

The figures show one embodiment of the construction method according to the present invention. Figure 1 is a perspective view of a prestressed concrete slab used for carrying out the construction method of the present invention, and Figure 2 is a schematic perspective view. Figure 3 is a front view, and Figure 4 is an enlarged perspective view of the main parts. A... Prestressed concrete floor slab (Ps floor slab)
, 4,4a=・POill material, ls−・・pam+u
, 16... Joint concrete. Applicant Ishikawajima Kenzai Kogyo Co., Ltd.

Claims (1)

[Claims] In a precast concrete slab that has ducts in the width and bridge axis directions (two directions), among the PC steel members placed in the width direction duct, at least one of the PC steel members located near both sides of the line is left aside, and other PC steel members are used. After tensioning to form a prestressed concrete deck slab, and installing the prestressed concrete deck slab on the main girder with both edges in the width direction set apart from each other with a predetermined joint spacing, PC steel material is pushed into the duct in the axial direction of the bridge. After applying joint concrete to the above joint and hardening it to a predetermined compressive strength, prestress is applied in the bridge axis direction, and prestress is applied to the unstressed PC steel near both sides of the width direction. A method for constructing prestressed concrete slabs for road bridges, etc., characterized by applying prestress to joint concrete in the off-axis direction and in the IIQJL direction by applying stress.