JP2008248529A - Straight road-type suspended floor slab bridge and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a straight road-type suspended floor slab bridge which makes a longitudinal road slope gentle by reducing a sag, and decreases a horizontal force acting on an abutment, and also to provide a construction method the straight road-type suspended floor slab bridge. <P>SOLUTION: The straight road-type suspended floor slab bridge comprises: a primary cable 3 for erecting a suspended floor slab; and a secondary cable 13 for supporting the whole of the bridge. Both the primary cable 3 and the secondary cable 13 are tensioned and anchored together by means of the abutment 2. A cable 9 for directly introducing prestress is arranged in a suspended floor slab body, and tensioned and anchored by an end of the suspended floor slab. The end of the suspended floor slab is supported by an elastic support without being fixed to the abutment 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a direct-type suspension floor slab bridge using an external cable and a construction method thereof.

  There is a direct suspension type slab bridge A shown in Fig. 11 as a PC suspended floor slab bridge in which PC steel material stretched between abutments and piers is wrapped with thin concrete and made into a floor slab. There is an upper suspension type suspension floor bridge B shown in FIG. 12 (see, for example, cited documents 1 to 3 and non-patent document 1).

The direct-type suspension floor slab bridge A is a structure that allows people and cars to pass directly over the floor slab (suspended floor slab) that wraps the cable (primary cable) that spans between the abutments. As a structure, a sag (suspension) S remains on the road surface, and the structure is easy to bend. On the other hand, the upper-floor type suspension floor slab bridge B has a structure in which a vertical material (or truss diagonal member) 21 is erected on the suspension floor slab 20 and an upper floor slab 22 serving as a road surface is placed on the vertical material 21. As a structure, the road surface is horizontal.
In the above case, although not shown in the drawings, the prestress-introducing PC steel material disposed in the suspended floor slab of the direct suspension type slab bridge A is tension-fixed on the back surface of the abutment 2, and similarly the suspended floor in the upper suspension type suspension slab bridge B. The pre-stress introducing PC steel material disposed in the plate 20 is tension-fixed on the back surface of the abutment 2. Further, the upper floor slab cable of the upper-floor type suspension floor slab bridge B is fixed at the bridge axial direction end of the upper floor slab 22. Further, since the vertical material 21 and the concrete upper floor slab 22 are placed on the suspended floor slab 20, the weight is increased, and the horizontal force borne by the cable or the abutment 2 and the anchor material is not reduced (the sag of the suspended floor slab is greatly increased). If this is done, the horizontal force is reduced, but the weight is offset because the weight is increased). However, this has the advantage that the overall rigidity is higher than that of the straight suspension type slab bridge A. The present invention belongs to the straight-line type suspension floor slab described above.

A conventional suspension floor slab bridge is generally constructed by placing a precast floor slab on a PC cable stretched between abutments and then placing post-cast concrete.
Conventionally, in suspended floor slab bridges for long spans, it is possible to reduce the horizontal force acting on the abutment by arranging an outer cable as a secondary cable and providing a vertical member between the precast floor slab and the outer cable. Known (see Patent Documents 2 and 5).
Japanese Patent No. 2967874 Japanese Patent No. 2979297 Japanese Patent No. 3678719 Japanese Patent Laid-Open No. 11-323841 JP-A-10-140521 PC floor slab bridge design and construction standards (draft) P4, 5, 11 November 2000, Prestressed Concrete Technology Association

  By the way, the setting of the basic sag is the most important thing in the suspension floor slab bridge. The sag is the number of cables, horizontal force acting on the abutment and the number of ground anchors, vibration during operation, wind resistance stability, straight type floor slab bridge. It will be considered as an important factor because it will affect the maximum vertical slope, landscape, drainage plan, etc.

  The sag ratio of suspended floor slab bridges (along with the road longitudinal gradient by sag in parentheses) is often 1/30 (13.3%) to 1/50 (8%) between the suspension branches. When the longitudinal gradient (sag ratio is also shown) is 6.7% (1/60) or less, for example, when the road longitudinal gradient (sag ratio) is 3% (1 / 133.3) or less, the upper surface of the suspended floor slab is Since it is closer to the horizontal plane, there is a great merit that the pedestrian can walk easily and can be barrier-free.

However, the reason why the sag (longitudinal gradient of the road) of the suspended floor slab is set to 1/30 (13.3%) to 1/50 (8%) between the suspension branches as described above is as follows.
If the suspension floor plate end is fixed to the abutment as a supporting condition for the suspension floor plate end, the suspension floor plate end can be changed to abutment due to creep, drying shrinkage and temperature change of the suspension floor plate when the sag is reduced. This is because the acting tensile force (mainly horizontal force) increases and it is difficult to establish a structure.

  In addition, it is also known that prestress is introduced into the girder member by releasing the primary cable for slab erection (see, for example, Patent Document 4), but when this is applied to a straight-line suspension floor slab, it is completed. In the system, the suspended floor slab itself is not in a state of being directly suspended by a cable, so that consideration must be given to torsion.

As described above, when the sag is made smaller than the fixed structure for fixing the suspended floor slab to the abutment, the tensile force due to creep, drying shrinkage, and temperature change is increased, making it difficult to establish the structure as the end of the suspended floor slab. In addition, in determining the structure of a suspended floor slab, stability against torsion is required.
The present invention provides a straight-line suspension floor slab bridge that can solve the above-mentioned problems, can reduce the sag and loosen the road longitudinal gradient, and can reduce the horizontal force acting on the abutment, and a construction method thereof. For the purpose.

In the straight-line type suspension floor slab bridge of the first invention, in the direct-line type suspension floor slab bridge, a primary cable for constructing the suspension floor slab and a secondary cable supporting the entire bridge body are provided, and the primary cable and the secondary cable are Both are fixed in tension on the abutment, and a cable for directly introducing prestress is arranged on the suspended floor slab body, and the tension is fixed on the end of the suspended floor slab, and the suspended floor slab end is not fixed to the abutment.
In the second invention, the saddle and the suspended floor slab are supported by the primary cable in the direct path type suspended floor slab of the first invention, and the saddle and the suspended floor slab are arranged adjacent to each other.
In the third invention, the direct cable type suspended floor slab bridge of the first invention or the second invention is characterized in that the secondary cable supports the suspended floor slab via a vertical member.
According to a fourth aspect of the present invention, in the direct path type suspended floor slab bridge according to any one of the first to third aspects of the invention, the end of the suspended floor slab is supported by the abutment via a support.
According to a fifth aspect of the present invention, there is provided a method for constructing a straight-line suspension floor slab bridge. In the method for constructing a direct-line suspension floor slab bridge, a suspension floor slab is installed with a primary cable, and the entire bridge body is supported with a secondary cable. After the tension of the secondary cable and the secondary cable is fixed on the abutment, the end suspended floor slab of the suspended floor slab supported on the abutment is constructed, and the cable that directly introduces prestress into the suspended floor slab body is arranged. The tension is fixed at the end of the suspended floor slab, and the end suspended floor slab is not fixed to the abutment.

According to the straight-line suspension floor slab bridge of the present invention, the end suspension floor slab is in a state of being separated without being fixed to the abutment, so that the floor slab bridge is creeped and dried as in the conventional fixed structure. Since the tensile force acting on the abutment due to shrinkage and temperature change does not increase, the horizontal force acting on the abutment can be reduced, and the sag can be reduced. From the above, it is possible to provide a direct-type suspension floor slab bridge with a structure that improves barrier-free for pedestrians with a small road longitudinal gradient.
In addition, when the sag is reduced to, for example, about 3% in the road longitudinal gradient, if the suspension floor plate end is fixed to the abutment, the horizontal force acting on the abutment increases due to the tension of the secondary cable, or the end of the suspension floor slab However, in the present invention, the suspended floor slab end is separated from the abutment and separated, so that the horizontal force acting on the abutment and the bending of the suspended floor slab end are caused by the tension of the secondary cable. Prestress can be introduced by the cable placed in the suspended floor slab without increasing the moment.
Moreover, according to the construction method of the direct route type suspension floor slab bridge of the present invention, in the construction method of the direct route type suspension floor slab bridge, the suspension floor slab is constructed with a primary cable, and the entire bridge body is supported with a secondary cable. After fixing the cable and the secondary cable on the abutment, construct an end suspension floor slab at the end of the suspension floor slab supported on the abutment and place the cable that directly introduces prestress into the suspension floor slab body Then, the tension is fixed at the end of the suspended floor slab, and the end suspended floor slab is not fixed to the abutment. Therefore, a straight-line suspended floor slab bridge having a structure in which the end suspended floor slab is not fixed to the abutment can be easily constructed. In addition, after the primary cable and the secondary cable are tensioned and fixed on the abutment, the end suspended floor slab may be provided on the support of the installation on the abutment, so that effects such as easy construction can be obtained.

    Next, the present invention will be described in detail based on the illustrated embodiment.

  FIG. 1A to FIG. 9 show an embodiment of the straight-line suspension floor slab bridge 1 of the present invention, and the primary cable 3 is fixed in a tensioned state between the abutments 2. In addition, a large number of precast intermediate suspended floor slabs 5 (see FIG. 6) except for the end suspended floor slabs 4 (see FIG. 8f) are laid in series on the primary cable 3, and a large number of serially arranged An end suspension floor slab 4 as an end of the suspension floor slab installed on the elastic bearing device 6 installed on the abutment 2 is connected to the primary cable 3 and the end of the intermediate suspension slab 5 in the bridge axis direction. It is provided so as to be supported by the elastic bearing device 6. The end suspension floor slab 4 as the end of the suspension floor slab is provided in a state separated from the abutment 2 and acts on the abutment 2 from the end suspension floor slab 4 to the abutment 2 due to creep, drying shrinkage and temperature change of the floor slab bridge. The tensile force to be applied is not increased.

  As the elastic bearing device 6, a known elastic bearing device having an elastic layer such as rubber is installed, and a vertical load of the end suspension floor slab 4 and the intermediate suspension floor slab 5 or a lateral direction such as a direction perpendicular to the bridge axis is provided. It is cushioned elastically against fluctuations. A bearing device 6 such as a steel bearing device other than the elastic bearing device 6 may be used.

As shown in FIG. 1 (b), each of the intermediate suspended floor slab 5 and the end suspended floor slab 4 has a saddle 7 to be supported by the primary cable 3 in the floor slab width direction perpendicular to the bridge axis. A plurality are provided at intervals. The saddles 7 are arranged so as to be placed on the plurality of primary cables 3, and the intermediate suspended floor slabs 5 constituting the suspended floor slab 17 are supported by the primary cables 3. The end suspension floor slab 4 is supported by a support device, and a saddle 7 is appropriately provided on the end suspension floor slab 4.
The lower surface of the downward opening groove on the saddle 7 side may be placed on the primary cable 3, and as shown in FIG. 10, the saddle 7 disposed in the suspended floor slab body may be supported by the primary cable 3. Good. The saddle 7 may be attached to the suspended floor slab body 5b so as to be exposed to the outside as shown in FIG. 1 and FIG. 5 (a).
Moreover, when the intermediate cable suspension floor slab 5 or the end suspension floor slab 4 is supported by the primary cable 3, as shown in FIG. 5 (b), concave portions 23 are formed on both sides on the upper surface side of the suspension floor slab, A form in which a plurality of suspension jigs 24 are embedded in the recess 23 may be employed. The suspension jig 24 is used to insert the primary cable 3 below the suspension jig 24 and to construct the intermediate suspension floor slab 5 or the end suspension floor slab 4 between the abutments 2 and 2. May be embedded with post-cast concrete 25 as a post-filling material to be placed in the recess 23 (however, the suspended floor slabs 4 and 5 are shown in FIG. As shown in a), the primary cable 3 must be slidable in the bridge axis direction). As shown in FIG. 5 (b), the primary cable 3 may be inserted under the hanging jig 24, or may be inserted into the saddle 7 as shown in FIG. 5 (c).
In addition, in FIG. 1 etc., in order to make the prestress introduction cable 9 and the primary cable 3 easy to understand, for convenience, the primary cable 3 is slightly below the intermediate suspension floor slab 5 and the end suspension floor slab 4. The saddle 7 having a predetermined length in the bridge axis direction is simply indicated by a circle.

In the width direction of the floor slab in each of the intermediate suspended floor slabs 5 and the end suspended floor slabs 4, cable insertion holes 8 are formed by being embedded in sheaths and are disposed in the respective cable insertion holes 8. The prestress introduction cable 9 is fixed by the fixing bracket 10 in a tensioned state at the end of the end suspension floor slab 4 (see FIG. 2).
1 and 3, the saddle 7 may be disposed outside the cross section of the suspended floor slab 5, but if the saddle 7 is disposed near the center of the suspended floor slab 5, it becomes unstable during installation. It arranges in the middle part from the width direction outside.
In the form of FIG. 5C, the cable insertion hole 8 is disposed in the intermediate portion in the width direction of the suspended floor slab, and the saddle 7 is disposed on the end portion in the width direction of the suspended floor slab, as shown in FIGS. As described above, the cable insertion hole 8 may be disposed on the width direction intermediate portion and both end sides of the suspended floor slab, and the saddle 7 may be disposed on the width direction end portion side of the suspended floor slab.

  A large number of intermediate suspension floor slabs 5 are provided with supports 11, and each intermediate suspension floor slab 5 and each support 11 form a three-dimensional truss, and each support 11 includes vertical members 12a, 12a, 12b, 12b and a cross member 12d are provided as main parts (see FIG. 3). The end suspension floor slab 4 is the same as the intermediate suspension floor slab 5 except that the support 11 is not provided.

As shown in FIG. 3, vertical members 12 a and 12 a are pivotally attached to the lower surfaces on both sides of the intermediate suspended floor slab body 5 b via bearings 12 e and 12 e so as to be rotatable in the bridge axis direction, Vertical members 12b and 12b are pivotally attached to the lower surface of the center of the floor slab body 5b where the primary cable 3 is not disposed via bearings 12f and 12f so as to be rotatable in the direction of the bridge axis. The members 12a and 12b are integrated at the lower end, and are connected to each other by being pivotally attached to the same connecting tool 12c via the lateral pin joint 27 so as to be pivotable in the bridge axis direction. 12c and a horizontal member 12d are pivotally attached to each other through a vertical pin joint 28, and a secondary cable insertion hole 14 for inserting the secondary cable 13 is formed in the connector 12c. Yes. Thus, the vertical members 12b, 12b are pivotally attached to the central lower surface of the intermediate suspended floor slab 5 so as to support the central lower surface portion of the intermediate suspended floor slab 5 from below together with the action of the secondary cable 13. . The vertical members 12a, 12a, 12b, and 12b that are arranged and connected to each other in this way are kept at a predetermined distance or more and integrated with the cross member 12d and the intermediate suspended floor slab 5 as one construction unit. Is forming.
As described above, since the structure is provided with a pair of vertical pin joints 28, each secondary cable 13 in FIG. 3 is a connecting structure that allows the movement in a different direction in the bridge axis direction. The pair of vertical members 12a and 12b has a structure that keeps a distance following this.
The vertical members 12b and 12b and the horizontal cross member 12d may be attached so as to be rotatable in all directions. However, a structure that is attached or connected in a structure that is rotatable in the bridge axis direction, for example, a pin structure. Is desirable.

  The support 11 has secondary cable insertion holes 14 at the lower ends of both ends in the direction perpendicular to the bridge axis, and the secondary cables 13 are inserted and arranged, and the ends of the secondary cables 13 are fixed to the abutment 2 in tension. Has been. Both ends of the primary cable 3 and the secondary cable 13 are fixed to the abutment 2 with a predetermined distance in the vertical direction (or horizontal direction, not shown).

  As described above, the fixed ends of the primary and secondary cables 3 and 13 are separated by a predetermined length, so that the rigidity of the bridge as a whole is improved, the torsional frequency of the suspended floor slab bridge is increased, and resistance to torsional divergence vibration is increased. Will improve.

  Further, in the straight-line suspension floor slab bridge 1 of the present invention, since a tension force is introduced into the secondary cable 13, a tensile stress is generated in the secondary cable 13, and the vertical members 12a, 12a, 12b, 12b Although an upward force from the secondary cable 13 acts, in particular, in the present invention, the integration of the intermediate suspended floor slab 5 is integrated after the tension of the secondary cable 13 is fixed and separated from the abutment. Therefore, due to the tension fixation of the secondary cable 13 or the tension fixation of the primary cable, the compressive stress in the bridge axis direction does not act on the intermediate suspended floor slab 5 and the bridge axis direction is applied to the abutment 2 via the floor slab. Compressive stress does not act. That is, according to the present invention, prestress is not introduced into the intermediate suspension floor slab 5 and the end suspension floor slab 4 due to the tension fixation of the primary cable 3 and the tension fixation of the secondary cable 13. After tension fixation and tension fixation of the secondary cable 13, only the prestress introduction cable 9 of the inner cable disposed in the intermediate suspension floor slab 5 and the end suspension floor slab 4 is the intermediate suspension floor slab 5 and the end. Prestress is directly introduced after the joint processing of the suspended floor slab 4 is performed, and the suspended floor slab 17 is introduced with prestress.

Furthermore, if the deflection (sag) of the secondary cable 13 is set to be larger than that of the primary cable 3 as shown in FIG. Because the load is borne by the secondary cable 13 having a larger deflection (sag) than the cable, the horizontal force acting on the cable structure that receives the same load between the same supports becomes smaller in inverse proportion to the amount of cable deflection. The total horizontal force acting on the substructure such as the abutment 2 and the ground anchor 16 can be reduced.
Further, in the present invention, the end of the suspended floor slab is separated from the abutment 2 and supported by an elastic bearing, so that the completed system suspended floor slab 17 and the road surface sag S1 can be reduced, and the road longitudinal gradient can be reduced. For example, it can be reduced to about 3%.

  Next, the construction process of the direct route type suspended floor slab bridge of the present invention will be described.

  FIGS. 6 to 9 show the construction process of the straight-line suspension floor slab bridge of the present invention. The abutment 2 is constructed on a ground (not shown), and a ground anchor 16 is provided on each abutment 2. As shown in FIG. 6A, the primary cable 3 is stretched between the abutments 2, and both ends of the primary cable 3 are tensioned to each abutment 2 as shown in FIG. To settle.

Next, as shown in FIG. 6 (b), the intermediate suspended floor slab 5 provided with the support 11 is sequentially installed from one abutment 2 toward the other abutment 2 so as to be supported by the primary cable 3. The positions of the installed intermediate floor slabs 5 are appropriately fixed.
As the position fixing means of the intermediate floor slab 5, the position may be fixed by a clamp fitting provided on the intermediate suspended floor slab 5 (not shown), for example.

  Next, as shown in FIG. 7 (c), the intermediate suspended floor slab 5 provided with the support 11 is erected from one abutment 2 to the other abutment 2 except for the position just above the abutment 2 to fix the position. After that, as shown in FIG. 7 (d), the secondary cable 13 is installed so as to engage with the vertical member at the lower part of each intermediate suspension floor slab 5 from one abutment 2 to the other abutment 2. . In constructing the secondary cable 13, a suspension scaffold (not shown) is appropriately constructed from one abutment 2 to the other abutment 2 and constructed using the suspension scaffold. In addition, you may install the said suspension scaffold at the time of suspension floor slab construction.

  Next, as shown in FIG. 8 (e), while adjusting the tension of the secondary cable 13, the sag of the intermediate suspension floor slab 5 is adjusted, and the end of each secondary cable 13 is fixed to the abutment 2. To do.

Next, as shown in FIG. 8 (f), the elastic bearing device 6 is installed on each abutment 2, and the upper surface of the elastic bearing device 6 is used as a part of the mold device to make the elastic bearing device 6. Each end suspended floor slab 4 made of concrete is constructed as a suspended floor slab end so as to be connected to the intermediate suspended floor slab 5 on the end side. The upper surface of the bearing device 6 may be slidably supported in the direction of the bridge axis as a sliding bearing surface. Accordingly, a gap in the bridge axis direction is formed between the abutment 2 and the end suspension floor slab 4, and if necessary, the expansion joint material or the expansion device having a known bridge axis direction expansion / contraction action in the gap. May be arranged.
Bolts or anchor bolts are appropriately provided on the upper portion of the elastic bearing device 6 so as to be integrated with the end suspension floor slab 4. The elastic bearing device 6 and the abutment 2 are fixed with bolts or the like.
As the elastic bearing device 6, a type B bearing device is used. However, depending on the scale of the straight-line suspension floor slab bridge, a type A bearing device may be used.

Next, in order to allow the prestress introduction cable 9 to be inserted and arranged, a sheath is appropriately arranged, and a joint material is provided between the intermediate suspended floor slabs 5, and after the joint material is cured, it is shown in FIG. Thus, the prestress introduction cable 9 is inserted and arranged across each end suspension floor slab 4 and the intermediate suspension floor slab 5 between them, and the prestress introduction cable 9 is tensioned to end suspension suspension slab 4. Tension settles in. Thus, the tension force of the prestress introduction cable 9 is applied to the abutment 2 by fixing the tension of the prestress introduction cable 9 to the rear surface of the abutment 2 but by fixing the tension at the end of the end suspension floor slab 4. Will not work. Further, the saddle 7 and the primary cable 3 of the intermediate suspension floor slab 5 and the end suspension floor slab 4 are in a completed system in a state where the lower surface of the downward opening recess 26 of the saddle 7 is engaged.
Next, as shown in FIG. 9 (h), the bridge surface on the end suspension floor slab 4 and the intermediate suspension floor slab 5 is constructed, and the railing 15 is constructed as shown in FIG. Complete construction of bridge 1.
In the form in which the primary cable 3 is disposed on the saddle 7 of the intermediate suspension floor slab 5 and the end suspension floor slab 4 (see FIGS. 2, 3, and 10), the recess or insertion of the primary cable for the saddle 7 is inserted. Since the hole is a support part such as a plastic pipe, it is not necessary to fill the filler in the completed system.

  In the above-described embodiment, (1) in the conventional straight-line suspension floor slab bridge, the primary cable is integrated with the suspension floor slab, but the primary cable 3 is formed as an external cable through a saddle 7. (2) Further, the entire bridge body (the entire end suspended floor slab and the entire intermediate suspended floor slab) is supported by the secondary cable 13 of the outer cable having a larger sag than the primary cable 3. (3) Further, the end suspended floor slab supported by the support device 6 installed on the abutment 2 without fixing the prestress introduction cable 9 that has been conventionally fixed on the abutment 2 backside. No. 4 is firmly established. From the three points (1), (2) and (3), the horizontal force acting on the abutment 2 can be greatly reduced even when the sag of the bridge body is small. As described above, in the present invention, the horizontal force acting on the abutment is kept small in the straight-line suspension floor slab bridge that allows a person or a vehicle to pass directly over the suspended floor slab wrapped with PC concrete stretched between the abutments. In addition to increasing resistance to torsional vibration, the vertical gradient (sag) is further reduced to increase barrier-free for pedestrians.

  In the form of fixing the suspension floor slab end to the abutment, in the case of the conventional structure, when the sag is reduced to, for example, about 3% by the road longitudinal gradient, when the suspension floor slab end is fixed to the abutment, due to the tension of the secondary cable, The horizontal force acting on the abutment increases or a large bending moment occurs at the end of the suspended floor slab, but in the present invention as described above, the suspended floor slab end is separated from the abutment and is in a separated state, Due to the tension of the secondary cable, prestress can be introduced by the cable arranged in the suspended floor slab without increasing the horizontal force on the suspended floor slab.

(A) is a schematic side view which shows the direct route type suspended floor slab bridge of this invention, (b) is a vertical front view which shows the arrangement | positioning relationship of a floor slab, a primary cable, a secondary cable, and the cable for prestress introduction. It is a schematic side view which expands and shows a part of FIG. It is a longitudinal front view which shows the relationship with a floor slab and a vertical material. FIG. 4 is a side view of FIG. 3 viewed from a direction perpendicular to the bridge axis. The various forms of the positional relationship between the primary cable and the saddle or the suspended floor slab are shown, wherein (a) is a form in which a saddle is disposed outside the suspended floor slab, (b) is a form in which a hanging jig is disposed, (c ) Is an explanatory view showing a form in which the saddle is arranged on the suspended floor slab. (A) And (b) is a schematic side view which shows the construction process of the direct route type suspension floor slab bridge of this invention. (C) And (d) is a schematic side view which shows the construction process of the direct route type suspension floor slab bridge of this invention. (E) And (f) is a schematic side view which shows the construction process of the direct route type suspension floor slab bridge of this invention. (G) And (h) is a schematic side view which shows the construction process of the direct route type suspension floor slab bridge of this invention. It is a vertical front view which shows the relationship with the floor slab of another form, and a vertical material. It is a schematic side view which shows the conventional direct route type suspended floor slab bridge. It is a schematic side view which shows an upper road type slab bridge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Direct route type suspension floor slab bridge 2 Abutment 3 Primary cable 4 End floor slab 5 Middle part suspension floor slab 6 Bearing device 7 Saddle 8 Cable insertion hole 9 Prestress introduction cable 10 Fixing bracket 11 Support body 12a Vertical member 12b Vertical member 12c Connector 12d Cross member 12e Bearing 12f Bearing 13 Secondary cable 14 Secondary cable insertion hole 15 Hand rail 16 Ground anchor 17 Suspended floor slab 20 Suspended floor slab 21 Vertical material 22 Upper floor slab 23 Recess 24 Suspension jig 25 Downward concrete 26 Downward Opening recess 27 Horizontal pin joint 28 Vertical pin joint A Straight-line suspension floor slab bridge B Upper-floor floor slab bridge

Claims (5)

  In a direct-type suspension floor slab bridge, a primary cable for laying the suspension floor slab and a secondary cable for supporting the entire bridge body are provided, and both the primary cable and the secondary cable are tension-fixed at the abutment, and the suspended floor slab body The direct suspension type slab bridge is characterized in that a cable that directly introduces prestress is placed and tension is fixed at the end of the suspended floor slab, and the end of the suspended floor slab is not fixed to the abutment.   The straight-line suspension floor slab bridge according to claim 1, wherein the saddle and the suspension floor slab are supported by a primary cable, and the saddle and the suspension floor slab are disposed adjacent to each other.   The straight cable type suspended floor slab bridge according to claim 1 or 2, wherein the secondary cable supports the suspended floor slab via a vertical member.   The straight-line-type suspension floor slab bridge according to any one of claims 1 to 3, wherein the end portion of the suspension floor slab is supported by an abutment via a support.   In the construction method of a straight-line suspension floor slab bridge, the suspension floor slab is installed with a primary cable, the entire bridge body is supported with a secondary cable, and the primary cable and the secondary cable are tensioned and fixed on the abutment. The end suspended floor slab is supported at the end of the suspended floor slab supported by the support, and a cable that directly introduces prestress into the suspended floor slab body is placed and tension is fixed at the end of the suspended floor slab. A method for constructing a direct-type suspension floor slab bridge characterized by not being fixed to an abutment.

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