JP2007169886A - Composite structure of main girder and precast floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein a bridge has longitudinal and transverse gradients and its installation is adjusted by changing a haunch height, and the haunch is machined by bending a lower face steel plate, whle since the longitudinal and transverse gradients differ every panel, the precast floor slabs with haunches are manufactured one by one to cause a cost increase. <P>SOLUTION: A connecting steel plate 2 formed with connecting bent parts with high strength bolt insertion holes 2b bored on both sides is laid between an upper flange of a main girder 4 and a bottom steel plate lower face of the precast floor slab 1 with a high strength bolt connecting nut 5 embedded in concrete 1a from the lower face of a bottom steel plate 1b. The precast floor slab 1 and the connecting steel plate 2, and the upper flange 4a of the main girder 4 and the connecting steel plate, are fastened by the high strength bolts 6 respectively through the bored high strength bolt insertion holes 2b. Concrete is then filled from a concrete filling hole of the precast floor slab to provide the composite structure of the main girder and the precast floor slab. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite structure of a main girder in a composite girder of a bridge and a precast floor slab manufactured in a factory.

  The cross-sectional force of the main girder is a structure in which the stud girder and floor slab are synthesized by melting a stud bolt on the main girder upper flange and placing concrete or mortar on the part.

Japanese Patent No. 2941632

Theory and Design of Steel / Concrete Composite Structure (1) Fundamentals: Theoretical Society, Japan Society of Civil Engineers, page 33

  The problem with precast slabs is in the synthesis with the main girder. Specifically, this is due to the precast slab haunch. The bridge has a longitudinal cross slope, and the adjustment of the installation of the precast slab is supported by changing the height of the hunch. Specifically, the bottom steel plate of the precast floor slab was bent and processed. Each panel has different vertical and horizontal gradients, so the production of precast floor slabs with hunches is one by one, which increases costs.

  In the case of composite girders by floor slab replacement, it is necessary to cut off existing stud bolts or stoppers using steel molds and newly plant stud bolts. At this time, since the quality of the vegetation falls unless the existing position is removed from the vegetation position, it is difficult to arrange a new stud bolt.

  In the case of composite girders when floor slabs are replaced, and traffic regulations must be released daily, the composite structure of main girders and precast slabs must be completed every day. It becomes tight in the process and leaves a problem in quality.

  In the conventional synthetic structure with the main girder (the gap between the precast floor slab with a haunch and the main girder is filled with non-shrinkable mortar), the synthetic effect decreases when the gap (3 cm or more) increases. If the haunch is high, the stud bolt will bend due to fatigue and the shear strength per stud bolt will decrease. As a countermeasure, the allowable force of the stud bolt per one is reduced and the number is increased.

  The present invention seeks to solve the problems caused by the precast slab haunch as described above.

  Basically, a connecting steel plate formed with connecting bent parts with high-strength bolt insertion holes penetrating the top and bottom surfaces at the appropriate intervals in the main girder direction at substantially the ends on both sides in the direction perpendicular to the bridge axis is used for precast slabs. A precast floor slab in which nuts for high-strength bolts to be screwed into high-strength bolts inserted through high-strength bolt insertion holes drilled in connecting bent parts in the concrete from the bottom steel plate bottom surface are embedded at appropriate intervals in the main girder direction. Precast floor with bottom steel plate and high-strength bolt insertion holes penetrating the upper and lower surfaces at the both sides of the main girder upper flange in a haunch shape on the main girder upper flange upper surface drilled at appropriate intervals Plate and connecting steel plate, main girder upper flange and connecting steel plate, high strength bolt coupling nut embedded in precast floor slab and high strength bolt insertion hole drilled in connecting steel plate, main girder upper flange and connecting steel plate drilled High strength bolt Through the hole and fastened with high-strength bolts, provides a synthetic structure of the main girder and precast floor slab, characterized in that filling the concrete from the concrete filling hole of the precast slab.

  Preferably, in the above, the composition of the main girder and the precast floor slab in which a nut is attached to the connecting bent portion from above the high strength bolt insertion hole position drilled in the connecting bent portion of the connecting steel plate to be fastened to the main girder upper flange Provide structure.

  Preferably, in the above, a composite structure of a main girder having a hand hole opened at an appropriate interval in a main girder direction between connecting bent portions of a connecting steel plate and a precast floor slab is provided.

  In this composite structure, the cross-sectional stress of the main girder is such that the main girder and the precast slab are placed between the upper flange of the main girder and the precast floor slab by connecting steel plates joined by friction welding with high-strength bolts. Synthetic action.

  The present invention has the following effects.

  In Claim 1 thru | or 3, adjustment of the haunch height of the precast floor slab with respect to a longitudinal cross gradient can respond | correspond by processing only a connection steel plate. In addition, the bending of each precast floor slab is not performed, leading to cost reduction.

  The composite action of the floor slab according to claim 1 or 2, wherein the high-strength bolt of the main girder upper flange portion and the friction on the precast floor slab side are applied to the acting shear force generated at the interface between the main girder upper flange and the concrete. It is exerted by the force, the tension and shear rigidity of the connecting plate, the embedded nut, and the flat holding by the filled concrete. Therefore, the main girder and the stud bolt for the precast floor slab are unnecessary.

  In the first to third aspects, the floor slab span can be fitted almost at the center, so that the precast floor slab can be installed open every day in the floor slab replacement work.

  In claim 1 to claim 3, since the stud bolt is not used for the main girder and the shearing force is transmitted by the connecting steel plate, even if the gap between the precast floor slab and the main girder becomes large, it is possible to suppress the deterioration of the composite effect. it can.

  In claim 2, since the nut is attached to the connecting bent portion from above the position of the high strength bolt insertion hole drilled in the connecting bent portion of the connecting steel plate fastened to the main girder flange, This makes it easy to connect bolts and nuts.

  In claim 3, since the hand hole is opened at an appropriate interval in the direction of the main girder between the connecting bent portions of the connecting steel plate, the hand can be inserted from the hand hole, and the main girder upper flange and the connecting steel plate Easy to connect with bolts and nuts.

  1 to 3 show an embodiment of the present invention. FIG. 1 is a schematic perspective view, and FIG. 2 is a cross-sectional view of the precast floor slab as viewed from the direction of the main girder at a position between concrete filling holes. 3 is a cross-sectional view of the precast floor slab as viewed from the direction of the main girder at the concrete filling hole position.

  1 is a precast floor slab, 2 and 3 are a pair of connecting steel plates that form a haunch shape together with a concrete floor slab lower surface and an upper flange of the main girder 4, and 4 is a main girder.

  The precast slab 1 is composed of a bottom steel plate 1b synthesized on the lower surface of the concrete 1a, and a concrete filling hole 1c that penetrates the bottom steel plate 1b from the upper surface of the concrete 1a at an appropriate interval in the direction of the main girder 4 in the main girder 4 equivalent position. Being done.

  This precast floor slab 1 includes a connecting fold of connecting steel plates 2 and 3 spanned between the upper flange 4a of the main girder 4 and the bottom steel plate 1b at an appropriate interval in the direction of the main girder 4 from the lower surface of the bottom steel plate 1b to the concrete 1a. A cylindrical nut 5 in which an internal thread for a high-strength bolt that fastens the curved portions 2a and 3a is screwed is embedded.

  The connecting steel plates 2 and 3 have a length in the length direction of the precast floor slab 1 and are connected bent portions connected to the bottom steel plate 1b of the precast floor slab 1 and the main girder 4 upper flange on both sides in the direction perpendicular to the bridge axis. 2a and 3a are formed by bending.

  In the connection bent portions 2a and 3a, high-strength bolt insertion holes 2b and 3b for fastening the precast floor slab 1 and the upper flange 4a of the main girder 4 with high-strength bolts 6 at appropriate intervals in the main girder 4 direction. Is perforated. Further, nuts 7 are attached to the high-strength bolt insertion holes 2b and 3b of the upper flange of the main girder 4 from the connection bent portions 2a and 3a side. The plate width between the connection bent portions 2a and 2a and between the connection bent portions 3a and 3a is processed to a width corresponding to the height of the hunch.

  The main girder 4 includes an upper flange 4a, a web 4b, and a lower flange 4c. The upper flange 4a connects the precast floor slab 1 and the upper flange 4a of the main girder 4 at appropriate intervals in the main girder 4 direction. The high strength bolt insertion holes 4d that match the high strength bolt insertion holes 2b and 3b of the connection bent portions 2a and 3a of the connecting steel plates 2 and 3 are drilled.

  The precast floor slab 1 thus formed, the pair of connecting steel plates 2 and 3 and the main beam 4 are fastened as follows.

  The precast floor slab 1 and the connecting steel plates 2 and 3 are made by matching the high strength bolt nuts 5 and the high strength bolt insertion holes 2a and 3a embedded in the precast floor slab 1 with the high strength bolts 6 respectively. -Insert from the lower surface side of 3 and screw the external thread of the high strength bolt 6 and the internal thread of the nut 5 for the high strength bolt.

  The connecting steel plates 2 and 3 and the main girder 4 are aligned with the other high strength bolt insertion holes 2a and 3a of the connecting steel plates 2 and 3 and the high strength bolt insertion holes 2b and 3b of the upper flange 4a of the main girder 4. Then, the high strength bolt 5 is inserted from the lower surface of the upper flange 4a, and the external screw of the high strength bolt 5 and the internal screw of the nut 7 are screwed together.

  At the position of the concrete filling hole 1c of the precast floor slab 1, a slab anchor 8 for preventing lifting is planted on the upper flange 4a of the main girder 4 as necessary.

  After the precast floor slab 1, the connecting steel plates 2 and 3 and the main girder 4 are fastened, concrete is filled from the concrete filling hole 1c penetrating the precast floor slab 1.

  Thus, a composite structure of the precast floor slab 1 and the main beam 4 is formed.

  What is necessary is just to perform the connection between the precast floor slabs 1 using a well-known splicing steel plate, for example.

  4 and 5 show another embodiment of the present invention. FIG. 3 is a side view (right side view or left side view), and FIG. 5 is a main view of the precast floor slab at a position between concrete filling holes. It is sectional drawing which looked at the digit direction.

  In this embodiment, there is a place where hand holes 9 are opened at appropriate intervals in the direction of the main beam 4 between the connection bent portions 2a and 2a of the connecting steel plates 2 and 3 and between 3a and 3a. Different from the previous embodiment. By opening the hand hole 9, a hand is inserted from the hand hole 9 without attaching the nut 7 to the upper surface of the connecting bent portions 2b and 3b located on the upper flange 4a of the main beam 4 of the connecting steel plates 2 and 3. A nut 7 can be screwed onto the high-strength bolt 6 inserted from the upper flange 4a side of the main girder 4.

  In addition, 10 is a spacer inserted in order to maintain the space between the bottom steel plate of the precast floor slab 1 and the upper flange of the main girder 4 as necessary.

  Since the present invention is constructed as described above, construction is performed in the following procedure on site.

1. After removing the existing floor slab that can be replaced in one day, remove the existing stud or slab anchor.
2. The ground surface of the connecting bent portions 2a and 3a of the connecting steel plates 2 and 3 to the upper flange 4a of the main girder 4 is processed by a grinder or the like so as to obtain a predetermined friction coefficient.
3. A slab anchor 8 for preventing floating is melted at a predetermined position on the upper flange 4a of the main girder 4.
4). A steel / concrete precast floor slab 1 manufactured in a factory is installed at a predetermined position. A height adjusting FRP spacer 10 is fixed to the upper flange 4a of the main beam 4 in advance with a double-sided tape or the like.
5. A high-strength bolt insertion hole 4d (about 1 / m) necessary for temporary fixing of the floor slab is made in the upper flange of the main girder 4.
6). The connecting steel plates 2 and 3 are fastened to the upper flange 4 a and the steel / concrete precast floor slab 1 with high-strength bolts 6. At this time, the high-strength bolt 6 on the upper flange side is fastened to the connecting steel plates 2 and 3 through the hand hole 9. The high-strength bolt insertion hole 4d required as a composite structure after completion is drilled upward from the scaffolding etc. in a state where traffic is opened after the floor slab is installed, and the high-strength bolt through the hand hole 9 provided in the connecting steel plates 2 and 3 Fasten with 6.
7). The old and new seams will be equipped with rehabilitation plates to open traffic.
8). When the construction of one unit (from joint to joint) of steel / concrete precast floor slab 1 is completed, mutual connection (attachment plate) is performed.
9. After the connection is completed, concrete is placed through the concrete filling hole 1c provided in the steel / concrete precast slab 1 to ensure the composite effect.
10. After concrete curing, replace the floor slab on the secondary construction side in the same way.
11. After the construction on the secondary construction side is completed, the construction division positions are connected.
12 After all the floor slabs have been replaced, bridge work (waterproofing, paving, expansion joints) will be completed.

It is a schematic perspective view which shows one embodiment of this invention. It is sectional drawing which looked at the direction of the main girder in the position between concrete filling holes of the precast floor slab. It is sectional drawing which looked at the main girder direction in the concrete filling hole position of the precast slab. It is a side view (right side view or left side view) showing another embodiment of the present invention. It is sectional drawing which looked at the direction of the main girder in the position between concrete filling holes of the precast floor slab.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Precast floor slab 1a Concrete 1b Bottom steel plate 1c Concrete filling hole 2 Connection steel plate 2a Connection bending part 2b High strength bolt insertion hole 3 Connection steel plate 3a Connection bending part 3b High strength bolt insertion hole 4 Main girder 4a Upper flange 4b Web 4c Lower flange 4d High strength bolt insertion hole 5 High strength bolt nut 6 High strength bolt 7 Nut 8 Slab anchor 9 Hand hole 10 Spacer 11 Splicing steel plate

Claims (3)

Connected steel plates with connecting bent parts with high-strength bolt insertion holes penetrating the upper and lower surfaces at both ends in the direction perpendicular to the bridge axis at appropriate intervals in the main girder direction. A bottom steel plate bottom surface of a precast floor slab in which nuts for high-strength bolts that are screwed into high-strength bolts inserted through high-strength bolt insertion holes drilled in connection bent portions are embedded in the main girder at appropriate intervals; A high-strength bolt insertion hole that penetrates the upper and lower surfaces of the upper side of the main girder upper flange is punched over the upper surface of the main girder upper flange in the main girder direction at appropriate intervals, precast floor slabs and connecting steel plates, High strength bolt coupling nut and main strength girder upper flange and connecting steel plate embedded in precast floor slab respectively, high strength bolt insertion hole drilled in connecting steel plate, high strength bolt insertion hole drilled in main girder upper flange and connecting steel plate Through High strength and bolted, composite structure of the main girder and precast floor slab, characterized in that the filling concrete from concrete filled hole precast slab. The main girder according to claim 1, wherein a nut is attached to the connection bent portion from above the position of the high-strength bolt insertion hole drilled in the connection bent portion of the connecting steel plate fastened to the upper girder upper flange. Composite structure of precast floor slab. The composite structure of a main girder and a precast floor slab according to claim 1, wherein hand holes are opened at appropriate intervals in the direction of the main girder between the connection bent portions of the connecting steel plates.

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