JP7619811B2 - Deck slab lifting device and deck slab lifting method using same - Google Patents

Description

The present invention relates to a deck slab lifting device used during deck slab erection work and a method for lifting a deck slab using the same.

In bridge deck installation work, where the deck is lifted and installed on the bridge girder, in order to ensure the flatness of the deck after it is installed on the bridge girder, it is necessary to suppress deformation of the deck when lifting and lowering it during installation so as not to apply unnecessary stress.

Conventionally, a large number of hanging fittings are embedded in a precast concrete deck (hereafter referred to as PCa deck) to provide multi-point hanging, and a lifting scale made of steel members assembled in a ladder shape to minimize bending stress is used to lift the PCa deck by hanging wires vertically from the lifting scale.

Specifically, as shown in Figure 2, in the case of a pretensioned prestressed concrete deck P1 (hereafter referred to as a PC deck), it is common to lift it at eight points using a lifting balance. However, even in this case, it was necessary to check that the load was evenly distributed on each of the lifting materials (each wire) at the lifting point by adjusting the length of the lifting wires and other lifting materials with a chain block 5 and measuring the tension on each lifting material with a load meter.

This required checking the load at eight locations and coordination between each location, making the work more difficult and requiring eight workers, which led to increased costs. There was therefore a need for a deck slab suspension device that could reduce the number of workers required and enable easy installation in a short time.

For example, Patent Document 1 discloses a suspended balance device 1 that includes a balance body 2, a counterweight 3 attached to the rear end of the balance body 2, a bracket holder 4 attached to the front end of the balance body 2, and a hanging member such as a wire 61 for hanging the balance body 2, and that is length-adjustable using a chain block 7 (see paragraphs [0017] to [0047] of the specification of Patent Document 1, and Figures 1, 5, 6, etc. of the drawings).

However, the hoisting balance device 1 described in Patent Document 1 is a hoisting balance device used when attaching brackets to bridge piers to prevent the bridge from falling over, and is not applicable to deck construction work. Furthermore, the invention described in Patent Document 1 does not at all recognize the above-mentioned issues when hoisting the deck so as not to apply bending stress to it.

JP 2020-84634 A

The present invention was devised in consideration of the above-mentioned problems, and its purpose is to provide a deck slab lifting device and a deck slab lifting method using the same that can be easily performed by a small number of people in a short time and that does not apply unnecessary stress to the deck.

The deck slab suspension device of claim 1 is a deck slab suspension device for lifting a deck, and comprises a suspension balance frame body made of combined steel materials, a plurality of fixed pulleys attached to the suspension balance frame body, and a plurality of suspension materials for lifting the deck that are inserted through the fixed pulleys, and is characterized in that one end of each of the plurality of suspension materials is connected to one of the plurality of suspension fittings attached to the deck, and is inserted through two adjacent fixed pulleys of the plurality of fixed pulleys, and the other end is connected to a different suspension fitting of the plurality of suspension fittings .

The deck slab suspension device of claim 2 is the deck slab suspension device of claim 1, characterized in that each of the multiple suspension members is length adjustable using a manually operated length adjustment jig.

The deck slab suspension device of claim 3 is the deck slab suspension device of claim 2, characterized in that each of the multiple suspension members is equipped with a load meter so that tension can be measured.

The method of lifting a deck according to claim 4 is a method of lifting a deck using the deck lifting device according to any one of claims 1 to 3, characterized in that the hanging material is inserted through two adjacent fixed pulleys, both ends of the hanging material are respectively connected to different hanging fittings of a plurality of hanging fittings attached to the deck, and the deck is lifted using the deck lifting device.

The method of lifting a deck according to claim 5 is a method of lifting a deck using the deck lifting device according to claim 3, characterized in that the hanging material is inserted through two adjacent fixed pulleys, both ends of the hanging material are respectively connected to different hanging fittings of a plurality of hanging fittings attached to the deck, and the deck is lifted using the deck lifting device, and the length of each of the plurality of hanging materials is adjusted with the length adjustment jig so that the measurement values of the load meters are as uniform as possible.

According to the inventions of claims 1 to 5, both ends of the hanging material inserted into two adjacent fixed pulleys are connected to different hanging fittings, so the tension applied to the hanging material when lifting the different hanging fittings is approximately equal, making it easy to lift without applying unnecessary stress to the deck slab. In addition, the number of personnel required for each hanging fitting can be halved, making it possible to easily and quickly install the deck slab with a small number of personnel.

In particular, according to the invention of claim 5, the length of each of the plurality of hanging members is adjusted with a length adjustment jig so that the measurement values of the load meters are as uniform as possible, so that no unnecessary stress is applied when the deck is lifted, and the flatness of the deck can be ensured after it is erected on the bridge girder.

FIG. 1 is a schematic diagram showing the state in which a deck is being lifted using a deck hoisting device according to an embodiment of the present invention, where (a) is a front view seen in the bridge axis direction, and (b) is a vertical cross-sectional view seen perpendicular to the bridge axis. FIG. 2 is a schematic diagram showing the state in which a deck is being lifted using a conventional deck lifting device, where (a) is a front view seen in the bridge axis direction, and (b) is a vertical cross-sectional view seen perpendicular to the bridge axis.

Below, an embodiment of the deck slab lifting device and deck slab lifting method according to the present invention will be described in detail with reference to the drawings.

[Deck slab suspension device]
First, a deck slab hoisting device 1 according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing a state in which a deck P1 is hoisted using the deck slab hoisting device 1 according to an embodiment of the present invention, where (a) is a front view seen in the bridge axis direction, and (b) is a vertical cross-sectional view seen in the direction perpendicular to the bridge axis. Note that the deck P1, which is a pretensioned PC deck, will be described as an example of the deck to be hoisted.

As shown in FIG. 1, the deck slab suspension device 1 according to this embodiment is a deck slab suspension device for lifting a deck P1. This deck slab suspension device 1 is composed of a suspension balance frame 2 made of a combination of steel materials, a number of fixed pulleys 3 attached to this suspension balance frame 2, and a number of suspension members 4 for lifting the deck P1.

(Suspension balance frame)
The hanging balance frame 2 has a frame body as its base, in which upper main steel materials 20, such as H-shaped steel, I-shaped steel, or channel steel, and lower main steel materials 21 are assembled in a crisscross pattern, and a number of auxiliary steel materials 23 are attached across the lower end of the lower main steel material 21 to increase rigidity, forming a ladder shape when viewed from above.

A lifting plate 24 protrudes upward from the upper end of the upper main steel member 20 of the lifting balance frame 2 for lifting with a lifting machine such as a crane. This lifting plate 24 has a lifting hole 24a formed therein, and can be lifted with a sling wire W1 that is hooked to a lifting machine via a metal fitting such as a shackle S1 or a round ring R1.

A hanging plate 25 for hanging the fixed pulley 3 is protruded downward from the lower end of the lower main steel material 21 of the hanging balance frame 2. A hanging hole 25a is formed in this hanging plate 25, and the fixed pulley 3 can be hung via a metal fitting such as a shackle S1.

(Fixed pulley)
The fixed pulley 3 is a so-called fixed pulley that is connected to the hanging plate 25 and does not move but only swings, and has the function of changing only the direction of the force acting on the hanging material 4 inserted through the fixed pulley 3 without changing the magnitude of the force. In the illustrated embodiment, four pairs of fixed pulleys 3, totaling eight, are attached according to the number of hanging plates 25 of the hanging balance frame 2.

(Hanging material 4)
The suspending member 4 is a wire rope made of a sling wire for hoisting the deck P1, and is passed through two adjacent fixed pulleys 3, 3 attached to the suspension plate 25 of the same lower main steel member 21. Of course, the suspending member 4 is not limited to a wire rope, and can be any long wire capable of suspending the weight of the deck P1 to be borne. Both ends of the suspending member 4 are connected to two different suspending fittings Hb attached to different positions on the deck P1 via chain blocks 5 and load meters 6, which will be described later. The suspending fittings Hb are attached to the deck P1 with embedded anchors.

A chain block 5 is attached to one end of the hanging material 4 via a round ring R2, and the length can be adjusted by the chain block 5. The chain block 5 is not limited to a chain block, and can be any manually operated length adjustment tool, such as a lever block (registered trademark).

A load meter 6 capable of measuring the stress (tension) acting on the hanging member 4, such as a load cell, is attached to the other end of the hanging member 4 via a round ring R2. This makes it possible to accurately grasp the stress (tension) acting on the hanging member 4. However, as described below, the number of load meters 6 that were previously required for each hanging bracket Hb on the deck P1 has been halved, which halves the effort and time required to check the load (stress).

[How to lift the deck]
Next, a method for lifting a deck P1 according to an embodiment of the present invention will be described with reference to Figures 1 and 2. The method will be described in comparison with the case of lifting a deck P1 using a conventional deck hoisting device 10 shown in Figure 2. Figure 2 is a schematic diagram showing a state in which a deck is being lifted using a conventional deck hoisting device, where (a) is a front view seen in the bridge axis direction, and (b) is a vertical cross-sectional view seen at right angles to the bridge axis. Note that the same reference numerals indicate the same configuration as the deck hoisting device 1 described above.

As shown in FIG. 2, the conventional deck slab lifting device 10 has a lifting balance frame 2 of the same configuration as the deck slab lifting device 1, and a chain block 5 is attached directly to the hanging plate 25 of the lifting balance frame 2, and its lower end is connected to a lifting bracket Hb via a load meter 6. For this reason, the conventional deck slab lifting device 10 is provided with a chain block 5 for each lifting bracket Hb corresponding to the lifting point for lifting the deck P1 as a lifting material for lifting the deck P1, and each chain block 5 is provided with a load meter 6.

In the conventional deck slab lifting device 10, the stress acting on each lifting point was checked with a load meter 6 to prevent unnecessary stress on the deck P1, particularly the stress lifting the lifting hardware Hb, which is the lifting point, from varying and causing bending stress on the deck P1.

In other words, with the conventional deck slab lifting device 10, the length of the chain block 5 had to be adjusted for each lifting fixture Hb, which is the lifting point of the deck P1, while checking the measurement value of the load meter 6, and moreover, these adjustments had to be done by workers communicating with each other. For this reason, with the conventional deck slab lifting device 10, a worker was required for each lifting fixture Hb, i.e., four locations along the direction perpendicular to the bridge axis when viewed from the front as shown in Figure 2(a) and two rows along the bridge axis direction as shown in Figure 2(b), for a total of eight lifting fixtures Hb.

Moreover, it was not just a matter of adjusting the length; changing the length of one chain block 5 would also change the measurement value of the load meter 6 at an adjacent location, so length adjustments had to be made in eight locations in coordination, making it a difficult and time-consuming task.

In contrast, as shown in Figure 1, in the deck slab suspension device 1 according to an embodiment of the present invention, as described above, one suspension member 4 is connected to two adjacent different suspension fittings Hb via a chain block 5 via two adjacent fixed pulleys 3, 3. Since the fixed pulley 3 only changes the direction of the force without changing the magnitude of the force, the two different suspension fittings Hb connected by the single suspension member 4 are lifted with approximately the same force. This eliminates the need to evenly adjust the force used to lift these suspension fittings Hb.

In other words, while the conventional deck slab suspension device 10 requires length adjustments at eight locations in coordination, the deck slab suspension device 1 only requires length adjustments at four locations in coordination. This significantly reduces the difficulty of the work, and the work time is not only halved, but can be completed in a much shorter time.

In addition, the deck slab lifting device 1 reduces the difficulty of the work, reducing the risk of unnecessary stress acting on the deck, making it easier to lift the deck P1 without unnecessary stress acting on it.

Furthermore, in the deck slab lifting device 1, the number of locations where the length is adjusted using the chain block 5 while checking the measurement value of the load meter 6 is halved from eight to four, so the number of personnel required for each lifting fixture Hb can be reduced by at least half. Furthermore, as the skill level of the workers increases, the difficulty of the work decreases, making it possible for them to adjust the length by working at two adjacent locations at the same time, and the number of workers required to lift the deck slab P1, which was eight, can be reduced to two, making it possible to carry out the work safely.

In short, according to the deck slab lifting device 1 according to the present embodiment and the deck slab lifting method according to the present embodiment using the deck slab lifting device 1 described above, deck installation work can be easily performed in a short time with a small number of personnel. Furthermore, according to the deck slab lifting device 1 according to the present embodiment and the deck slab lifting method according to the present embodiment using the deck slab lifting device 1, the difficulty of the work is reduced, so the risk of unnecessary stress acting on the deck can be reduced, making it easier to lift the deck P1 without unnecessary stress acting on it.

The deck slab lifting device 1 according to an embodiment of the present invention and the deck slab lifting method according to an embodiment of the present invention using the same have been described in detail above, but the embodiments described above and shown in the figures are merely examples of specific embodiments for implementing the present invention. Therefore, the technical scope of the present invention should not be interpreted in a limited manner based on these.

1: Deck slab lifting device 10: Conventional deck slab lifting device 2: Lifting balance frame 20: Upper main steel member 21: Lower main steel member 23: Auxiliary steel member 24: Lifting plate 24a: Lifting hole 25: Lifting plate 25a: Lifting hole 3: Fixed pulley 4: Lifting member 5: Chain block (manually operated length adjustment jig)
6: Load cell P1: PC floor slab (floor slab)
G1: Ground Hb: Suspension hardware R1, R2: Round rings S1: Shackle W1: Sling wire

Claims (5)

A deck slab lifting device for lifting a deck,
The suspension balance frame is made of a combination of steel materials, and a plurality of fixed pulleys are attached to the suspension balance frame. A plurality of suspension members are inserted through the fixed pulleys to hoist the deck.
A deck slab suspension device characterized in that one end of each of the multiple suspension members is connected to one of the multiple suspension members attached to the deck, and is inserted through two adjacent fixed pulleys of the multiple fixed pulleys, and the other end is connected to a different suspension member of the multiple suspension members . 2. The deck slab suspension device according to claim 1, wherein the length of each of the plurality of suspension members is adjustable by a manually operated length adjustment jig. 3. The deck slab suspension device according to claim 2, wherein each of the plurality of suspension members is equipped with a load meter so that tension can be measured. A method for lifting a deck using the deck lifting device according to any one of claims 1 to 3, comprising:
A method for lifting a deck, comprising: inserting the hanging material through two adjacent fixed pulleys, connecting both ends of the hanging material to different hanging fittings of a plurality of hanging fittings attached to the deck, and lifting the deck using the deck lifting device. A method for lifting a deck using the deck lifting device according to claim 3, comprising the steps of:
The suspending member is inserted through two adjacent fixed pulleys, and both ends of the suspending member are respectively connected to different suspending fittings of a plurality of suspending fittings attached to the deck slab, and the deck slab is hoisted using the deck slab hoisting device;
A method for lifting a deck slab, comprising adjusting the length of each of the plurality of hanging members with the length adjustment jig so that the measurement values of the load meters are as uniform as possible.

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