A reinforcement method for impact-damaged bridge main beam

Abstract

The present invention discloses a reinforcement method for a bridge main beam damaged by impact, which belongs to the field of bridge engineering and includes the following steps: cleaning the impact damage area, roughening the concrete of the main beam web at the edge of the impact damage area; roughening the auxiliary reinforcement area, dividing the auxiliary reinforcement area into a deep roughening interface area and a shallow roughening interface area; installing the formwork, pouring ultra-high performance concrete, removing the formwork after the ultra-high performance concrete reaches the design strength, grinding off the protruding reinforcement material around the joint, painting the entire beam, unifying the appearance of the main beam, and completing the reinforcement work. The present invention can not only ensure the bonding performance between the reinforcement material and the existing beam body, but also utilize the high tensile strength of the ultra-high performance concrete to improve the cracking strength of the interface between the damaged area and the undamaged area.

Description

Technical Field

[0001] The invention belongs to the field of bridge engineering, and in particular relates to a method for reinforcing a bridge main beam damaged by impact. Background Art

[0002] The rapid economic development has led to the continuous expansion of cities across my country, and the ensuing problem is increasingly congested traffic, which has led to the emergence of a large number of urban cross-line overpasses. Urban bridges play a pivotal role in the urban transportation system, but they also pose huge safety hazards. Due to improper operation by drivers, insufficient understanding of relevant road height restrictions, and an imperfect road administration system, accidents involving overheight vehicles hitting bridge structures are common, and the bridges damaged by these accidents account for more than 20% of all damaged bridges.

[0003] Regarding the problem of super-high vehicles hitting bridges, current research mainly focuses on analyzing the impact process, damage form and damage mechanism, but there is little research on the reinforcement methods of bridges damaged after the impact. At present, most bridges have been demolished and rebuilt for concrete bridge main beams damaged by vehicle impacts; at the same time, since the degree of damage to bridges after impact is generally high, the commonly used reinforcement methods cannot restore the stiffness, bearing capacity and durability of the bridges, and it is necessary to select appropriate reinforcement technology. The reinforcement methods suitable for damaged bridges are also different. At present, there are relatively few studies in this field. It is necessary to conduct in-depth research on the reinforcement technology of vehicle impact bridge main beams to provide guidance for the reinforcement of subsequent possible bridge impact accidents. Summary of the invention

[0004] The purpose of the present invention is to provide a method for reinforcing a bridge main beam damaged by impact, so as to solve the deficiencies in the prior art.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0006] A method for reinforcing a bridge main beam damaged by impact, comprising the following steps:

[0007] S1: Clean up the impact damage area

[0008] Clean up the concrete residues in the impact damage area, ensure that the concrete of the main beam web at the edge of the impact damage area is intact, cut off and weld the steel bars that are broken or have obvious plastic deformation due to the impact, ensure the lap length between the welded steel bars and the existing steel bars, and roughen the concrete of the main beam web at the edge of the impact damage area to form the side roughened surface and the upper roughened surface of the impact damage area;

[0009] S2: Chiseling the auxiliary reinforcement area

[0010] The auxiliary reinforcement area is the undamaged area around the impact damage area. Based on the requirement of interface shear force transmission, the auxiliary reinforcement area is divided into a deep roughening interface area and a shallow roughening interface area. The deep roughening interface area is adjacent to the impact damage area, and the shallow roughening interface area is adjacent to the deep roughening interface area.

[0011] S3: Installing formwork and pouring ultra-high performance concrete

[0012] Use a hair dryer to remove dust from the roughened area, spray water on all roughened surfaces until they are saturated and wet, install and fix the formwork, pour ultra-high performance concrete into the formwork from the upper pouring port, remove the formwork after the ultra-high performance concrete reaches the designed strength, grind off the protruding reinforcement materials around the joints, paint the main beams, unify the appearance of the main beams, and complete the reinforcement work.

[0013] Preferably, in step S2, the roughening depth of the deep roughening interface area is 1 times the thickness of the main beam web concrete protective layer, the web stirrups can be seen after roughening, and the width of the deep roughening interface area is 2 to 3 times the thickness of the main beam web.

[0014] Preferably, the roughening thickness in the deep roughening interface area close to the shallow roughening interface area gradually changes from 1 times the thickness of the concrete protective layer to 1 / 2 the thickness of the concrete protective layer.

[0015] Preferably, in step S2, the roughening depth of the shallow roughening interface zone is 1 / 2 of the thickness of the concrete protective layer of the main beam web, the width of the shallow roughening interface zone is 2 to 3 times the thickness of the main beam web, and the roughening thickness of the shallow roughening interface zone close to the unroughened area of ​​the main beam gradually changes to 0.

[0016] Preferably, in step S2, the shallow roughening interface area is provided with two or more deep roughening belts running vertically, and the roughening depth of the deep roughening belts is equal to the thickness of the main beam web concrete protective layer.

[0017] Preferably, in step S2, in addition to roughening both sides of the web of the main beam, the bottom surfaces of the deep roughening interface area and the shallow roughening interface area are also roughened to form a web bottom plate roughening interface area, and the roughening depth gradually decreases in a broken line pattern from twice the thickness of the concrete protective layer adjacent to the impact damage area toward the shallow roughening interface area.

[0018] The reinforcement method of a bridge main beam damaged by impact provided by the present invention has the following advantages compared with the prior art:

[0019] The present invention provides a reinforcement method for a bridge main beam damaged by impact. It is not necessary to dismantle the bridge main beam damaged by impact. It is only necessary to roughen the concrete of the main beam web and the impact damaged area and a certain area around the impact damaged area according to the design of the present invention, and fill the damaged area and the roughened area with ultra-high performance concrete. The reinforcement can be completed when the ultra-high performance concrete reaches the designed strength. The present invention can not only ensure the bonding performance between the reinforcement material and the existing beam body, but also utilize the high tensile strength of ultra-high performance concrete to improve the cracking strength of the interface between the damaged area and the undamaged area. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the elevation structure of the main beam of the bridge damaged by impact before reinforcement according to the present invention;

[0022] Figure 2 for Figure 1 Cross-sectional view at AA;

[0023] Figure 3 for Figure 1 Cross-sectional view at BB;

[0024] Figure 4 for Figure 1 Cross-sectional view at CC;

[0025] Figure 5 for Figure 1 Cross-sectional view at DD;

[0026] Figure 6 for Figure 1 Cross-sectional view at EE;

[0027] Figure 7 It is a schematic diagram of the facade structure of the main beam of the impact-damaged bridge after reinforcement according to the present invention;

[0028] Figure 8 for Figure 7 Cross-sectional view at FF;

[0029] Fig. 9 for Figure 7 Cross-sectional view at GG;

[0030] Fig.10 for Figure 7 Cross-sectional view at HH;

[0031] Fig.11 for Figure 7 A cross-sectional view at II;

[0032] Fig.12 for Figure 7 Cross-section at JJ;

[0033] Fig.13 The force analysis of the present invention Figure 1 ;

[0034] Fig.14 The force analysis of the present invention Figure 2 ;

[0035] Fig.15 It is the location diagram of the weak area of ​​the present invention.

[0036] In the figure: 1-main beam, 3-main beam web, 4-impact damage area, 5-side roughened surface, 6-deeply roughened interface area, 7-shallowly roughened interface area, 8-web bottom plate roughened interface area, 10-upper roughened surface, 11-deeply roughened belt, 12-ultra-high performance concrete. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0038] refer to Figure 1-12 As shown, the present invention provides a method for reinforcing a bridge main beam damaged by impact, comprising the following steps:

[0039] S1: Clean up impact damage area 4

[0040] Clean up the concrete residues in the impact damage area 4, ensure that the concrete of the main beam web 3 at the edge of the impact damage area 4 is intact, cut off and weld the steel bars that are broken or have obvious plastic deformation due to the impact, ensure the lap length between the welded steel bars and the existing steel bars, and roughen the concrete of the main beam web 3 at the edge of the impact damage area 4 to form the side roughened surface 5 and the upper roughened surface 10 of the impact damage area 4;

[0041] S2: Chiseling the auxiliary reinforcement area

[0042] The auxiliary reinforcement area is the undamaged area around the impact damage area 4. Based on the demand for interface shear force transmission, the auxiliary reinforcement area is divided into a deep roughening interface area 6 and a shallow roughening interface area 7. The deep roughening interface area 6 is adjacent to the impact damage area 4, and the shallow roughening interface area 7 is adjacent to the deep roughening interface area 6. In view of the problem that the bonding strength between the existing concrete of the main beam 1 and the reinforcement material in the damaged area is low, and the interface bonding strength is easily failed under tension, the reinforcement method of the present invention divides the entire reinforcement area into three reinforcement areas, namely the impact damage area 4, the deep roughening interface area 6 and the shallow roughening interface area 7. The purpose of setting the deep roughening interface area 6 and the shallow roughening interface area 7 is to convert the normal bonding force between the existing concrete of the main beam 1 and the reinforcement material in the damaged area into the shear force between the concrete in the non-impact damage area and the reinforcement material, so as to maximize the bonding force between the reinforcement material in the damaged area and the existing beam body, so that the reinforcement material and the existing beam body are subjected to force in a coordinated manner.

[0043] S3: Install formwork and pour ultra-high performance concrete 12

[0044] Use a high-power hair dryer to remove dust from the roughened area, spray water on all roughened surfaces until they are saturated and wet, install and fix the formwork, pour ultra-high performance concrete 12 into the formwork from the upper pouring port, remove the formwork after the ultra-high performance concrete 12 reaches the designed strength, grind off the protruding reinforcement materials around the joints, paint the entire beam, unify the appearance of the main beam 1, and complete the reinforcement work.

[0045] As a preferred embodiment, in step S2, the roughening depth of the deep roughening interface area 6 is 1 times the thickness of the concrete protective layer of the main beam web 3, and the web stirrups can be seen after roughening. The width of the deep roughening interface area 6 is 2 to 3 times the thickness of the main beam web 3.

[0046] As a preferred embodiment, the roughening thickness of the deep roughening interface area 6 close to the shallow roughening interface area 7 gradually changes from 1 times the thickness of the concrete protective layer to 1 / 2 the thickness of the concrete protective layer.

[0047] As a preferred embodiment, in step S2, the roughening depth of the shallow roughening interface area 7 is 1 / 2 of the thickness of the concrete protective layer of the main beam web 3, the width of the shallow roughening interface area 7 is 2 to 3 times the thickness of the main beam web 3, and the roughening thickness of the shallow roughening interface area 7 close to the unroughened area of ​​the main beam 1 gradually changes to 0.

[0048] As a preferred embodiment, in step S2 , the shallow roughening interface area 7 is provided with two or more deep roughening bands 11 running vertically through, and the roughening depth of the deep roughening bands 11 is equal to the thickness of the concrete protective layer of the main beam web 3 .

[0049] As a preferred embodiment, in step S2, in addition to roughening both sides of the main beam web 3, the bottom surfaces of the deep roughening interface area 6 and the shallow roughening interface area 7 also need to be roughened to form a web bottom plate roughening interface area 8, and the roughening depth gradually decreases in a broken line pattern from twice the thickness of the concrete protective layer adjacent to the impact damage area 4 toward the shallow roughening interface area 7.

[0050] The principle of the present invention is:

[0051] refer to Figure 13-15 As shown in the figure, the normal tension between the reinforcement material in the damaged area and the undamaged beam body ( Fig.13 ) is converted into most of the tangential force + part of the normal force ( Fig.14 ) to ensure that the reinforcement material has sufficient bonding strength with the existing beam interface. In addition, the high tensile strength of the reinforcement material ultra-high performance concrete is used to improve the weak area ( Fig.15 ) cracking load, we have verified the effectiveness of this reinforcement through experiments.

[0052] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0053] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0054] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for reinforcing a bridge main beam damaged by impact, characterized in that: The steps include: S1: Clean the impact damage area (4) Cleaning concrete residues in the impact damage area (4), ensuring that the concrete of the main beam web (3) at the edge of the impact damage area (4) is intact, cutting and repairing the steel bars that are broken or have obvious plastic deformation due to the impact, ensuring the lap length between the repaired steel bars and the existing steel bars, and roughening the concrete of the main beam web (3) at the edge of the impact damage area (4) to form a roughened side surface (5) and an upper roughened surface (10) of the impact damage area (4); S2: Chiseling the auxiliary reinforcement area The auxiliary reinforcement area is an undamaged area around the impact damage area (4). Based on the requirement of interface shear force transmission, the auxiliary reinforcement area is divided into a deep roughening interface area (6) and a shallow roughening interface area (7). The deep roughening interface area (6) is adjacent to the impact damage area (4), and the shallow roughening interface area (7) is adjacent to the deep roughening interface area (6). The shallow roughening interface area (7) is provided with two or more deep roughening belts (11) that run through from top to bottom. The roughening depth of the deep roughening belts (11) is equal to the thickness of the concrete protective layer of the main beam web (3). In addition to roughening both sides of the main beam web (3), the bottom surfaces of the deep roughening interface area (6) and the shallow roughening interface area (7) are also roughened to form a web bottom plate roughening interface area (8). The roughening depth gradually decreases in a broken line pattern from twice the thickness of the concrete protective layer adjacent to the impact damage area (4) toward the shallow roughening interface area (7). S3: Install formwork and pour ultra-high performance concrete (12) A hair dryer is used to remove dust from the roughened area, water is sprayed on all the roughened surfaces until the roughened surfaces are saturated and wet, the formwork is installed and fixed, and ultra-high performance concrete (12) is poured into the formwork from the upper pouring port. After the ultra-high performance concrete (12) reaches the designed strength, the formwork is removed, the protruding reinforcement material around the joint is polished off, the main beam (1) is painted, the appearance of the main beam (1) is unified, and the reinforcement work is completed.

2. A method for reinforcing a bridge main beam damaged by impact according to claim 1, characterized in that: In step S2, the roughening depth of the deep roughening interface area (6) is 1 times the thickness of the concrete protective layer of the main beam web (3), and the web stirrups can be seen after roughening. The width of the deep roughening interface area (6) is 2 to 3 times the thickness of the main beam web (3).

3. A method for reinforcing a bridge main beam damaged by impact according to claim 2, characterized in that: The roughening thickness of the deep roughening interface area (6) close to the shallow roughening interface area (7) gradually changes from 1 times the thickness of the concrete protective layer to 1 / 2 the thickness of the concrete protective layer.

4. The method for reinforcing a bridge main beam damaged by impact according to claim 1, characterized in that: In step S2, the roughening depth of the shallow roughening interface area (7) is 1 / 2 of the thickness of the concrete protective layer of the main beam web (3), the width of the shallow roughening interface area (7) is 2 to 3 times the thickness of the main beam web (3), and the roughening thickness of the shallow roughening interface area (7) close to the unroughened area of ​​the main beam (1) gradually changes to 0.

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