CN111663441A - Wave-mode plate base structure composite material for bearing surface of bridge and other large-scale structures - Google Patents

Abstract

The invention discloses a type of corrugated board-based structural composite material for structural bearing planes. This type of corrugated sheet-based structural composite consists of one or more basic units comprising corrugated sheets; each basic unit is characterized by the implantation of specially designed meso-shaped and sized sheets between two specially selected flat or curved basic sheets. Plates to form regularly arranged open or closed cavities; or fill the open cavities with other materials according to large-scale structural characteristics and load types; so as to make full use of the combined properties of materials and the structural characteristics of the cavities to achieve high strength, high Durability, and light weight for optimum application benefits. When this type of panel-based structural composite material is used as a pavement cover, it is attached to the referred large structure by one or a combination of the following methods: these methods are: riveting, welding, bolting, or simply resting on the bearing surface. When using riveting, welding, and bolting, ensure that the joint will not become a source of secondary fatigue defects.

Description

A class of corrugated slab-based structural composites for load-bearing surfaces of bridges and other large structures Material

technical field

The invention relates to the technical field of structural design and bearing surface repair of bridges, houses and other large-scale steel structures, which can be directly applied to the design of the bearing surface of the large-scale structure, or can be used as a pavement material to cover such load-bearing surfaces. superior. A possible wider application is bridge deck design, paving, or paving repair; in particular, orthotropic deck design, paving, or paving repair for long-span bridges. Figure 1(a) is an ortho-shaped steel box girder under construction; Figure 1(c) is a common crack in the deck roof of this type of ortho-shaped steel box girder. Fig. 1(d)(e) are the following two types of stress distribution calculated by the finite element model of Fig. 1(b) ortho-shaped steel box girder bridge [2, 3].

The present invention is a further innovation based on the applicant's US patent [1]. Compared with [1], the novelty and originality of the present invention are mainly reflected in the design of the basic plate shape and cavity of the unit according to the bearing method.

Background technique

The main considerations in the design of large structures are load-carrying capacity and durability. Considering a point on the surface of a structural component, the stress it bears can be simply divided into two categories: (1) the stress directly acting on the surface contact force, see Figure 1(d); (2) the surface contact force and other loads, Including the weight of the structure itself, the stress generated at this point is mainly the stress caused by the bending moment, see Figure 1(e). For example, two people standing on a bridge separated by a distance, the bridge deck under each person's feet feels the contact pressure of this person and the bending moment stress caused by the other person and the weight of the bridge itself.

For large structures, the bending moment and the corresponding stress caused by the weight of the component itself and the full load on the component, that is, the second type of stress mentioned above, are the main considerations in current engineering design. For example, for orthorectified steel box girders used in very large span bridges in recent decades, traditional codes allow ultra-thin (less than 12 mm) steel box girders to be designed to reduce their own weight. However, under the long-term repeated impact of vehicle wheels on the bridge deck, fatigue cracks caused by repeated contact loads appear in the welds of many such bridge decks around the world or around them. Since it is impossible to replace the 100-meter-long steel box girder due to individual local cracks; the continued expansion of cracks under the vehicle may lead to catastrophic consequences; welding closed cracks will cause new cracks around the weld, so generally only from the improvement of bridge deck paving Installed to ensure bridge safety. The traditional method is to cover the bridge deck with a pavement such as concrete or epoxy resin. Due to the disparity between these materials and steel materials, it is difficult to bond closely with the steel bridge deck. Under the effect of temperature changes and vehicle wheel loads, the pavement will fall off after three to five years and needs to be reprocessed. At the same time that the new bridge design improves the thickened steel box girder slabs, there have been many inventions that apply composite paving methods and inventions to improve the stress state of the bridge decks in operation [1, 4-10], for example, [1] This paper introduces the concept of applying multiple wave-shaped plates superimposed with cavity composite design to protect ortho-shaped steel box girder bridge decks. However, some methods are necessary to improve the strength, stiffness, corrosion resistance and fatigue resistance of themselves and their connecting parts with steel box girder and other aspects related to service life, because, according to the current conventional design, the service life of general bridges is 75 to 120 year. In order to ensure the safe operation of such bridges, the plate-based structural composite material of the present invention can be used as a permanent pavement material to repair and protect the panels of bridges in operation; A further innovation based on the US patent [1]. Compared with [1], the novelty and originality of the present invention is mainly reflected in the design of the connection mode of the cavity and the structural unit according to the contact load of the wheel and the characteristics of the bridge structure, so as to obtain better mechanical and material properties.

SUMMARY OF THE INVENTION

(1) Brief description: Provide a type of slab-based structural composite material that can be used as a large-scale structure bearing surface or such bearing surface covering pavement. Large structures here refer to bridges and house structures, other steel structures on land, ships, and offshore work platforms; here bearing surfaces refer to the surface planes or curved surfaces of these structures directly bearing external loads.

(2) Technical problem to be solved: applying the plate-based structural composite material provided by the present invention (a) to enhance the conventional strength such as compression and impact resistance of the bearing surface of large-scale structures, (b) to improve its fatigue resistance and wear resistance, etc. Durability index; (c) enhance the overall strength of large-scale structures; this type of plate-based structural composite material itself must (d) satisfy conventional strength indexes such as compressive and impact resistance, and durability indexes such as fatigue strength and wear resistance. e) Meet the additional rigidity and stability requirements for its own structure.

(3) Technical solution: In order to solve the above problems, the plate-based structure composite material provided by the present invention is composed of at least three types of the following eight types of material units according to the specific design conditions. These eight types of material units are shown in Fig. 2 The corrugated plate 3 in the middle, the upper top plate 4, the lower top plate 5, the filling material 7 of the upper cavity between the corrugated plate 3 and the upper top plate 4, the upper cavity rib 12 in the upper cavity, the filling of the corrugated plate 3 and the lower top plate. The lower cavity filling material 7 between 5, the lower cavity rib 11 in the lower cavity. A further explanation is as follows:

(1) The thickness of the corrugated plate 3 is 1 to 18 mm, and the corrugation height is 4 to 120 mm; the upper top plate 4 and the lower top plate 5 are connected by welding seams 10 at both ends of the repeated corrugation direction and spot welding 9 on the other two sides.

(2) The upper cavity filling material 7 and the lower cavity filling material 8 may be the same or different concrete or epoxy materials; their function is to ensure that the corrugated plate 3 does not experience local instability under compression.

(3) The upper cavity rib 14 and the lower cavity rib 15 are connected to the corrugated plate 3 by spot welding; their function is to ensure that the corrugated plate 3 does not suffer from local instability under pressure.

(4) The conventional pavement 11 placed on the upper roof 4 is, for example, conventional asphalt concrete.

(5) When this type of slab-based structural composite material is used as a pavement covering but does not need to simultaneously strengthen the strength and rigidity of the bearing surface of the covered large-scale structure, this type of slab-based structural composite material can simply be placed on the bearing surface.

(6) When this type of slab-based structural composite material is used as a pavement and needs to strengthen the strength and stiffness of the bearing surface of the covered large-scale structure, one of the following methods or a combination thereof shall be used to connect each piece of slab-based structural composite material to the Refers to large structures: these methods are: riveting, welding, bolting. However, riveted and bolted connections must drill holes in the load-bearing panels; welding can cause localized material dissimilation, for example, in the heat-affected zone, causing material embrittlement; therefore, the load-bearing face structure is inevitably weakened. In order to ensure that the joints using this method will not become the source of secondary fatigue defects, according to the analysis and test results of [2, 3], the selection conditions of riveting, welding and bolting positions 12 are specified:

(i) The dynamic load stress amplitude in any direction at the corresponding position of the structural bearing panel must be less than 1/3 of the maximum dynamic load stress amplitude borne by all materials in the entire structural bearing panel.

(ii) The average stress in any direction at the corresponding position of the structural load-bearing panel must be less than 1/2 of the maximum average stress borne by all material elements in the entire structural load-bearing panel.

According to conventional bridge design codes, such as [11-13], when the condition (i) is satisfied, the fatigue life (number of dynamic load cycles) of the material element at the reserved hole or welding position of the structural bearing panel is the fatigue life of the peak force element of the bearing panel (Number of cycles that can withstand dynamic loads) in cubes. According to the analysis and test results [2, 3], when the condition (ii) is satisfied, the fatigue life of the material element at the corresponding position of the reserved hole or weld can be increased by 50%. These two conditions ensure that the hot spots sensitive to secondary fatigue loss will not be formed by drilling holes in the corresponding positions of the structural load-bearing panels.

Description of drawings

Figure 1: (a) An example of an ortho-shaped steel box girder under construction; (b) a 3D finite element model of an ortho-shaped steel box girder bridge; (c) Common cracks in the roof deck of an ortho-shaped steel box girder bridge; (d) The stress distribution directly acting on the surface contact force; (e) The stress distribution corresponding to the bending moment caused by the surface contact force and other loads, including the weight of the structure itself.

Figure 2: The basic structure of the plate-based structure composite material of the present invention; including the upper and lower cavity filling materials.

Method of implementation

Method 1: The plate-based structural composite material is only composed of upper and lower roof plates and corrugated plates

(1) The corrugated sheet can be formed into a corrugated shape by cold pressing or hot pressing of a flat strip, or formed by a corrugated rolling mill.

(2) Place the corrugated plate on the lower top plate and the upper top plate on the corrugated plate; connect to each other by welding.

(3) Place on the bearing surface of the structure.

(4) According to the needs of the working conditions, they are connected by bolts or welded or riveted structural bearing panels.

(5) Add conventional pavement to the surface of the upper roof

Method 2: The plate-based structural composite material is only composed of upper and lower top plates, corrugated plates, and upper and lower cavity ribs

(1) The corrugated lath can be formed into a corrugated shape by cold pressing or hot pressing of a flat strip, or formed by a corrugated rolling mill.

(2) According to the needs of the working conditions, spot welding the upper cavity rib to the corresponding position of the corrugated plate.

(3) According to the needs of the working conditions, spot welding the lower cavity rib to the corresponding position of the corrugated plate.

(4) Place the corrugated plate on the lower top plate and the upper top plate on the corrugated plate; connect to each other by welding.

(5) Place on the bearing surface of the structure.

(6) According to the needs of the working conditions, they are connected by bolts or welded or riveted structural bearing panels.

(7) Add conventional paving, such as asphalt concrete, to the upper roof surface.

Method 3: The plate-based structural composite material is only composed of upper and lower roof plates, corrugated plates, upper and lower cavity ribs and filling materials

As in method 2, according to the working conditions, the upper cavity filling material should be built in the remaining space of the upper cavity after the completion of (2); and the lower cavity filling material should be built in the remaining space of the lower cavity after (3) according to the working conditions.

Method 4: The plate-based structure composite material is only composed of upper and lower top plates, corrugated plates, and upper and lower cavity filling materials

(1) The corrugated sheet can be formed into a corrugated shape by cold pressing or hot pressing of a flat strip, or formed by a corrugated rolling mill.

(2) Place the corrugated slats on the working platform with the same curvature as the structural bearing surface, and build the upper cavity filling material in the upper cavity according to the needs of the working conditions

(3) Connect with the upper top plate by spot welding; if necessary, build the lower cavity filling material in the lower cavity after turning over.

(4) Connect with the lower top plate by spot welding.

(5) Place on the bearing surface of the structure.

(6) According to the needs of the working conditions, they are connected by bolts or welded or riveted structural bearing panels.

(7) Add conventional paving, such as asphalt concrete, to the upper roof surface.

The reserved holes or welding positions in the lower top plate fixed by the method are determined according to the following criteria: (i) The dynamic load stress amplitude in any direction at the corresponding position of the structural bearing panel must be less than the maximum dynamic load borne by all materials in the entire structural bearing panel 1/3 of the stress amplitude. (ii) The average stress in any direction at the corresponding position of the structural load-bearing panel must be less than 1/2 of the maximum average stress borne by all material elements in the entire structural load-bearing panel. According to the bridge design code [2], when the condition (i) is satisfied, the fatigue life (number of cycles of dynamic load) of the material element at the reserved hole or welding position of the structural bearing panel is the fatigue life of the peak force element of the bearing panel (which can withstand the dynamic load). number of cycles) cubed. According to the analysis and test results [2], when the condition (ii) is satisfied, the fatigue life of the material element at the corresponding position of the reserved hole or welding can be increased by 50%. These two conditions ensure that no secondary fatigue loss sensitive hot spots are formed at the corresponding connection positions of the structural load-bearing panels.

references

[1] US Patent US9222260B1, priority date April 10, 2009

【2】Su Hao (Hao Su), Closure to "I35W Bridge Collapse" by S.Hao, ASCE J.ofBridge Engineering, V.18(9), 2013, pp.929-930.

[3] Su Hao (Hao Su, Structural Fatigue Damage Evaluation in Bridges and Orthotropic Decks, 3RD ORTHOTROPIC BRIDGE CONFERENCE PROCEEDINGS, June 26-28, 2013, Sacramento, California.

[4] French patent FR2411922B1 priority date December 15, 1978

[5] Canadian patent CA1074061A priority date May 26, 1983

[6] US Patent US5342141, priority date August 30, 1994

[7] Korean Patent KR20030097049A, priority date December 31, 2003

[8] Chinese patent CN103614964A priority date December 10, 2013

[9] US Patent US 8,888,941 B2 priority date June 4, 2013

[10] Chinese patent CNCN108457182A priority date May 18, 2018

[11] American Bridge Design Specification: AASHTO LRFD Bridge Design Specification 2016

[12] Japanese Bridge Design Code: Road and Bridge Instructions Book. With Commentary 2012

[13] Eurocode: Bridge Fatigue Design: Eurocode 3 (2005). Design of SteelStructures–Part 1-9: Fatigue, EN 1993-1-9

Claims (10)

1. A board-based structural composite material which can be used as a large-scale structural bearing surface or covered and paved by the bearing surface is provided. The large structures refer to bridges and building structures, other steel structures on land, ships, and ocean working platforms; the bearing surface refers to a surface plane or a curved surface of the structures which directly bear external loads. The board-based structure composite material is characterized in that:

-its composition comprises at least one corrugated-shaped sheet comprising a number of repeating wave-shaped units; the wave pattern of each unit comprises a straight line section and a curve section connecting the straight line section;

-its composition comprises a lower ceiling; the corrugated shaped plate is disposed above the lower top plate; a lower cavity is enclosed by one corrugation of the corrugated-shaped plate and the lower top plate;

-its composition comprises an upper top plate, placed above said corrugated shaped plate; a corrugation of the corrugated plate and the upper top plate enclose an upper cavity;

-the upper top plate, the lower top plate, and the corrugated shaped plate are connected to each other by welding;

-over the large structure bearing surface.

2. The board based structural composite of claim 1 wherein at least one of said lower cavities has at least one lower cavity rib block embedded therein; the lower cavity rib block is made of metal or epoxy resin or composite material including high strength concrete.

3. The board based structural composite of claim 1 wherein at least one upper cavity rib block is disposed within at least one of said upper cavities; the upper cavity rib block is made of metal or epoxy resin or composite material including high-strength concrete.

4. The board based structural composite of claim 1, wherein at least one of said lower cavities is filled with a lower cavity filler material; the lower cavity filling material is epoxy resin or high-strength concrete.

5. The board based structural composite of claim 1 wherein at least one of said upper cavities is filled with an upper cavity filler material; the upper cavity filling material is epoxy resin or high-strength concrete.

6. The board based structural composite of claim 2, wherein a lower cavity filler material is disposed in a remaining space after the lower cavity rib block is disposed in at least one of the lower cavities; the lower cavity filling material is epoxy resin or high-strength concrete.

7. The board based structural composite of claim 3 wherein the remaining space after the upper cavity rib block is placed in at least one of said upper cavities is filled with an upper cavity filler material; the upper cavity filling material is epoxy resin or high-strength concrete.

8. The board based structural composite of claim 2 wherein at least one of said upper cavities is filled with an upper cavity filler material; the upper cavity filling material is epoxy resin or high-strength concrete.

9. The board based structural composite of claim 8, wherein a lower cavity filler material is disposed in a remaining space after the lower cavity rib block is disposed in at least one of the lower cavities; the lower cavity filling material is epoxy resin or high-strength concrete.

10. The board based structural composite material according to claim 2, wherein a prepared hole is provided at a corresponding position of the large structure bearing surface and the lower top plate; the stress level of the reserved hole at the corresponding position of the bearing surface of the large structure is less than one third of the highest peak stress of all material units of the bearing panel; the large-scale structure bearing surface is connected with the lower top plate through a bolt passing through a preformed hole; the corrugated batten grids are connected with the lower top plate through welding.

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