CN100381641C - Widened box girder, combined slab section elevated road and its manufacturing and maintenance method - Google Patents

Abstract

A box girder (400) is provided, which comprises two or more wide box girders (1) and/or narrow box girders (2) each having an upper surface carrying a bridge deck, the wide box girders (1) and / Or the narrow box girder (2) extends in a straight line in the transverse direction, and is characterized in that there is a T-shaped connector (3) between two laterally adjacent box girders, and the upper transverse of the T-shaped connector (3) One end (4) of part (6) is lapped on the upper surface of a box girder, and the other end (4') is lapped on the upper surface of another adjacent box girder, and its lower vertical part (5) fills the The gap between the box girders. Also provided is an elevated road in a doubling section using the box girder (400) and a maintenance method thereof.

Description

Widened box girder, combined slab section elevated road and its manufacturing and maintenance method

technical field

The present invention relates to a widened box girder, and also relates to an elevated road made of the widened box girder, and a method for manufacturing and maintaining the elevated road.

Background technique

With the increasing development of the economy, plane transportation has become more and more difficult to meet the requirements. Therefore, many large and medium-sized cities alleviate traffic congestion by developing three-dimensional transportation. Elevated road is a commonly used three-dimensional traffic mode.

With the increase of the population (including the floating population and the resident population), the urban development space is becoming smaller and smaller, so new requirements are put forward for the elevated road, that is, the elevated road is required to occupy less land and have a beautiful appearance under the premise of ensuring smooth traffic. etc.

In addition, with the development of economy and society, new requirements are put forward for the construction of elevated roads: that is, civilized construction, no or less impact on the traffic near the construction site, and small impact on the environment. Most of the existing road construction methods adopt the on-site tamping and pouring method. This method needs to build steel pipe scaffolding, assemble formwork and carry out concrete tamping and pouring on the spot. Obviously, it is difficult to meet the requirements due to its large footprint, long construction period and large amount of dust generated.

In order to overcome the defects of the prior art and meet the above-mentioned requirements, a construction method of factory prefabrication, on-site assembly, and bridge erecting machine erection has been proposed.

The elevated road is basically composed of a column, a support placed on the column, a horizontal box girder placed on the support, and a vertical box girder erected between two adjacent horizontal box girders. The box girder is installed in the factory Prefabricated with the help of templates. Due to the high price of the formwork, in order to control the project cost, it is impossible to purchase a large number of formwork with different specifications in one project, and the formwork specifications that can be used are limited.

According to the design requirements, the elevated road generally has a certain width n ₁ , and this width (also referred to as the width of the main bridge deck) can generally meet the requirements of, for example, two-way 4-lane or 6-lane. When manufacturing elevated roads of this width, a formwork with a width of _m1 can be used to construct its box girder (hereinafter referred to as wide box girder).

Elevated roads will inevitably have on-ramps or optional emergency parking strips. The on and off ramps have a width n ₂ different from said width n ₁ . Can adopt the formwork that width is m ₂ to manufacture its box girder (hereinafter referred to as narrow box girder) when manufacturing described ramp.

For traffic considerations, the width of the elevated road is usually greater than the sum of the width n ₁ of the main bridge deck and the width n ₂ of the ramp (n ₁ +n ₂ ) at the junction of the on-ramp and/or the off-ramp and the main bridge deck. Sections of elevated roads with on-ramps or emergency parking areas inevitably require changes in road width. For example, on a road section with an on-ramp, it is required that the road surface should change from wide (that is, the width is greater than n ₁ +n ₂ ) to narrow from the junction of the on-ramp and the main bridge deck until the above-mentioned main bridge deck width n ₁ is reached. In the field, such a road section where the road surface changes from wide to narrow or from narrow to wide is called a "joint section". In order to meet traffic safety and visual requirements, the prior art adopts a method of gradually narrowing the width of the bridge deck from the junction of the on-ramp and the main bridge deck. When manufacturing this kind of slab section with gradually changing road width, the method of on-site stamping and pouring can be used, the method of factory-made box girders with gradually changing widths and subsequent on-site assembly, or the method of steel structure assembly can be used.

But above-mentioned existing method all has defect. For example, the method of pouring on site requires steel pipe scaffolding. This method has a long construction period, affects traffic and affects the environment due to the generation of dust, and does not meet the requirements of civilized construction; It overcomes the defects of the pouring-in-place method, but it requires the use of templates with various width gradients. There are two main defects in this method: firstly, it needs templates of various specifications, and because the templates are expensive, it inevitably increases the project cost; secondly, it needs at least a template with a width greater than n ₁ +n ₂ to make the width A box girder that meets the requirements, when the upper and lower ramps are on the same road section, it even needs an ultra-wide box girder with a width greater than n ₁ +2n _2. After the ultra-wide box girder is manufactured, a large vehicle needs to be transported to the site, which requires transportation and equipment. very high. In addition, because the elevated road in the combined plate section needs a certain road length to make the width gradually change to meet the requirements of traffic safety, if all the combined plate sections with steel structure are used, the cost will be unacceptably high.

Therefore, there is a need for a method for manufacturing and slab-section elevated roads using existing equipment to improve the utilization rate of formwork m ₁ and m ₂ .

content of the invention

The purpose of the present invention is to improve the utilization rate of formwork _m1 and _m2 in elevated road construction so as to reduce the construction cost of the project.

Accordingly, the present invention provides a widened box girder comprising two or more wide and/or narrow box girders each having an upper surface carrying a deck, said wide and/or narrow box girders Extending in a straight line in the transverse direction, it is characterized in that there is a T-shaped connector between two laterally adjacent box girders, and one end of the upper cross part of the T-shaped connector is lapped on the upper surface of a box girder, The other end is lapped on the upper surface of another adjacent box girder, and the vertical part thereof fills the gap between the box girders.

The present invention also provides an elevated road for parallel board sections, which is composed of parallel elevated roads for parallel board sections and elevated roads for parallel board section with gradually changing width. The parallel elevated road for parallel board sections includes columns, The widened transverse box girder and the longitudinal box girder erected between the widened transverse box girders are characterized in that each of the widened transverse box girders and longitudinal box girders is basically composed of a wide box for supporting the main bridge deck Beams, one or two narrow box girders extending in a straight line laterally along the wide box girders to support the ramp, and T-shaped connectors between two adjacent box girders.

Both the wide box girder and the narrow box girder include an upper surface for carrying the road surface, one end of the upper transverse part of the T-shaped connector is lapped on the upper surface of the wide box girder, and the other end is lapped on the narrow box girder. On the upper surface of the beam, the lower vertical portion fills the gap between the wide box girder and the narrow box girder.

The present invention also provides a method for manufacturing a parallel elevated road with parallel panels, which includes the following steps:

Two or three uprights extending along the width of the road are formed at prescribed intervals according to the required road width;

A wide box girder extending transversely and one or two narrow box girders extending transversely are respectively formed on the two or three uprights, the widths of the wide box girder and the narrow box girder extend in a straight line along the width of the road, and the Both wide and narrow box girders include an upper surface for carrying road slabs;

A wide box girder or a narrow box girder extending longitudinally is respectively hoisted between two adjacent wide box girders extending transversely or two adjacent narrow box girders extending transversely along the extending direction of the elevated road;

Between each pair of wide box girders and narrow box girders adjacent in the width direction of the elevated road, a T-shaped connector is formed, the width of the lower vertical part is such that it can be placed in the gap between the two box girders , the height of the lower vertical part is approximately equal to the height of the ends of the wide box girder and the narrow box girder; one end of the upper transverse part of the T-shaped connector is lapped on the upper surface of the wide box girder, and the other end is lapped on the upper surface of the wide box girder. On the upper surface of the laterally adjacent narrow box girders, so that the lower vertical part fills the gap between the wide box girder and the narrow box girder.

The manufacturing method of the present invention also includes the step of forming a pavement slab on the box girder.

The present invention also provides a method for maintaining the elevated road in the parallel parallel section of the present invention, which includes the following steps:

1) Set the column settlement warning value;

2) Regularly measure the settlement difference of two or three columns used to support the same widened box girder;

3) When the settlement difference reaches the early warning value, adjust the height of the support to control the wide box girder, the narrow box girder and the T-shaped connector placed between the wide box girder and the narrow box girder internal force.

Description of drawings

The present invention will be described in more detail below in conjunction with the accompanying drawings. In the attached picture:

Fig. 1 is the perspective view of elevated road of the present invention;

Fig. 2 is the top view of elevated road of the present invention;

Fig. 3 is the enlarged schematic diagram of Fig. 1 road box girder;

Figure 4 is an enlarged schematic view of a T-shaped connector of the present invention;

Fig. 5 is a schematic diagram of an existing ultra-wide box girder.

Detailed ways

A. Definition

Horizontal box girder: refers to the box girder supported on the pillars extending along the width direction of the elevated road;

Longitudinal box girder: refers to the box girder that is placed between two adjacent horizontal box girders and connected together by, for example, steel cables and horizontal box girders. The vertical box girder and the columns supporting the horizontal box girder constitute the bridge deck support system of the elevated road;

Transverse or width direction of horizontal box girder or vertical box girder: refers to the direction in which box girder extends laterally (widthwise) along the elevated road;

T-shaped connector: refers to the connector used to connect two laterally adjacent box girders in the parallel slab section and has a T-shaped shape, which has an upper horizontal part and a lower vertical part;

The width of the T-shaped connector: refers to the size of the T-shaped connector along the transverse or width direction of the box girder;

Wide box girder: refers to a horizontal box girder or a longitudinal box girder used to manufacture conventional road widths;

Narrow box girder: refers to the horizontal box girder or longitudinal box girder used to make the ramp;

Super-wide box girder: refers to a box girder whose width exceeds the sum of the width of a wide box girder and the width of a narrow box girder;

Combined section: refers to the road section where the elevated road changes from normal width to extra-normal width or from extra-normal width to normal width due to the setting of ramps and/or emergency parking belts;

Parallel merged section: refers to a road section with an extraordinary width in the merged section, and the width of the road section is roughly balanced;

Road section of normal width: refers to the road section whose width can ensure the normal passage of vehicles, such as a road section with two-way 4-8 lanes. Sections of road where the width of the road exceeds the normal width;

Merging section with gradually changing width: refers to the road section in the joining section used to connect the parallel parallel section and the elevated road with normal width;

B. Widened box girder and parallel elevated road

In the prior art, there are various box girders used for slab-joining sections, but no matter what kind of box girder, they all have the same design principle. For example, Figure 5 shows a typical existing ultra-wide box girder, whose shape is similar to enlarged wide box girder or narrow box girder. gravity.

After a lot of research, the inventor finds that not only the shape of this box girder can meet the requirements of the elevated road. Based on the studies, the present inventors came up with the present invention.

The present invention provides a widened box girder 400, as shown in FIGS. The wide box girder 1 and/or the narrow box girder 2 extend in a straight line in the transverse direction, and are characterized in that there is a T-shaped connector 3 between two laterally adjacent box girders 1 and 2, and the T-shaped connector 3 One end 4 of the upper transverse part 6 is lapped on the upper surface of one box girder, the other end 4' is lapped on the upper surface of another adjacent box girder, and its lower vertical part 5 fills the space between the box girders. void.

The widened box girder of the present invention will be described in more detail below in conjunction with the parallel-type elevated road of the present invention.

The existing elevated roads in the merged section are often designed as a merged section with gradual road changes. This kind of merged section road has a reasonable design and a beautiful appearance. FIG. 1 is a schematic diagram of an elevated road, which includes a doubling section 100 . As shown in the figure, when the shaded part is not considered, the amalgamation section 100 is an elevated road in an amalgamation section with gradually changing road width. This doubling section has a certain length, and its length spans the distance between four groups of uprights in FIG. 1 .

However, the disadvantage of this combined slab section is that it requires cast-in-place construction methods that affect traffic, or forms of various widths are required to prefabricate suitable box girders. If steel structures are used in order not to affect traffic during construction, the cost will be greatly increased.

In order to benefit the existing equipment to the greatest extent, the inventor has proposed a novel elevated road for parallel board sections. Composed of a parallel section elevated road 300 with gradually changing width, the parallel parallel section elevated road 200 includes a column 11, a widened box girder 400 placed on the column (ie, a horizontal box girder) and erected along the length of the viaduct. The vertical box girder between two widened horizontal box girders adjacent in direction is characterized in that the widened horizontal box girder and the vertical box girder are each basically composed of a wide box girder 1 for supporting the main bridge deck, one or Two narrow box girders 2 extending in a straight line laterally along the wide box girder 1 for supporting the ramp are composed of a T-shaped connecting piece 3 between two adjacent box girders.

Both the wide box girder 1 and the narrow box girder 2 include an upper surface for carrying the road surface, one end 4 of the upper cross part 6 of the T-shaped connector overlaps the upper surface of the wide box girder 1, and the other end 4' is lapped on the upper surface of the narrow box girder 2, and the lower vertical part 5 fills the gap between the wide box girder 1 and the narrow box girder 2.

The elevated road 300 with a gradually changing width in the parallel plate section of the present invention is, for example, assembled from steel structures. The method of the present invention can advantageously shorten the length of the road section using the steel structure, thereby not only ensuring the requirement of "less construction impact on traffic", but also Control the project cost.

The elevated road in the parallel parallel section of the present invention is mainly used for road sections with up-and-down ramps or emergency parking belts. Therefore, in a road section with an up-ramp or a down-ramp, the width of the parallel-type parallel section is greater than that of a main bridge The sum of the width n ₁ of the surface and the width n ₂ of a ramp (n ₁ +n ₂ ); in the road section with an up ramp and a down ramp at the same time, the width of the combined board section is greater than the width n of a main bridge deck ₁ and the sum of the widths 2n ₂ of the two ramps (n ₁ +2n ₂ ).

The invention is not limited to a widened box girder 400 formed by a wide box girder 1 and a narrow box girder 2 via a T-shaped connecting piece 3 . In a preferred example of the present invention, the widened box girder 400 includes a plurality of box girders formed by formwork _m1 or _m2 supported on pillars, and two box girders adjacent to each other in the transverse direction T-connectors between beams.

FIG. 4 shows a schematic diagram of the T-shaped connector 3 of the present invention. As shown in the figure, the T-shaped connector 3 of the present invention includes an upper horizontal portion 6 and a lower vertical portion 5 . The height of the lower vertical part of the connector is generally equal to the height of the lateral ends of the wide box girder 1 and/or the narrow box girder 2 . The width of the upper cross section 6 depends on the distance between the wide box girder 1 and the narrow box girder 2, that is, it can be any width as long as it can firmly connect the wide box girder and the narrow box girder. In the present invention, the term "firm connection" refers to such a connection mode, that is, the T-shaped connector can connect the wide box girder and the narrow box girder to form a widened box girder whose strength meets the design requirements.

The height of the upper transverse part 6 of the T-shaped connector (that is, the height of its protruding top surface 20 of the wide box girder 1 or the height of the top surface 21 of the narrow box girder 2) should ensure the strength of the final widened box girder. Affect the smoothness of the entire elevated road surface. In a preferred example of the present invention, said height is equivalent to the thickness of the reinforced concrete bridge deck laid on the top surface of the box girder, so that the upper surface of the concrete layer on the top surface of the box girder and the upper surface of the T-shaped connector roughly on a plane, so as not to affect the smoothness of the asphalt or concrete layer laid on the upper surface. .

The length of the lower vertical part of the T-shaped connector can be any length as long as it can firmly connect the wide box girder 1 and the narrow box girder 2 . In the present invention, the term "the length of the lower vertical part" refers to the distance from the lower top of the T-shaped lower vertical part to the connection with the upper horizontal part. However, from an aesthetic and economic point of view, the height of the lower vertical part preferably corresponds to the height of the end of the wide box girder and/or the narrow box girder, ie its lower end is preferably aligned with the end of the wide box girder or the narrow box girder. The width of the lower vertical part should be such that it can be placed in the gap between the wide box girder 1 and the narrow box girder 2 and be in close contact with its connected neighbors. In a preferred example of the present invention, the width of the lower vertical part of the T-shaped connector is 0.5-4.5 meters.

The T-shaped connector of the present invention can be made of conventional materials in the field. For example, it can be assembled from steel structures, or it can be poured from reinforced concrete. In a preferred embodiment of the invention, reinforced concrete cast T-connectors are used.

In summary, the present invention overcomes the technical prejudice in the art that the box girder must have the shape shown in Figure 5, and the wide box girder and the narrow box girder are connected by T-shaped connectors to form a widened box girder . As a result, the utilization rate of the existing box girder formwork is improved. On the premise that the construction interferes less with the traffic, the length of the steel structure road section is shortened, and the project cost is saved.

C. the manufacture method of elevated road of the present invention

The manufacture method of elevated road of the present invention comprises the steps:

1) Form two or more columns at prescribed intervals. The prescribed intervals depend on the width of the elevated road surface. Those of ordinary skill in the art can easily determine the interval between the columns according to requirements; in a better example of the present invention, the columns include two columns, one for supporting the wide box beam 1, one Used to support the narrow box girder 2;

2) On the two or more uprights, respectively form transverse box beams extending laterally along the road, and the transverse box beams all include an upper surface for carrying road slabs; in a preferred example of the present invention , the horizontal box girder includes two horizontal box girders, i.e. a wide horizontal box girder and a narrow horizontal box girder; Each box girder should be arranged in a straight line along its length, so as to be connected by T-shaped connectors;

3) A plurality of longitudinal box girders are respectively formed between two wide transverse box girders and two narrow transverse box girders adjacent along the extension direction of the elevated road, thereby forming two mutually separated elevated roads;

4) A T-shaped connector is formed between each pair of two laterally adjacent box girders; the width of the lower vertical part of the T-shaped connector is such that it can be placed in the gap between two adjacent box girders ;

5) One end of the upper transverse part of the T-shaped connector is lapped on the upper surface of a box girder, and the other end is lapped on the upper surface of another adjacent box girder, so that the lower vertical part is filled with the same The gap between two adjacent wide boxes. In a preferred example of the present invention, the two adjacent box girders are a wide box girder and a narrow box girder, and the T-shaped connector fills the gap between the wide box girder and the narrow box girder;

6) A merged section with gradually changing road width is formed at the junction of the parallel merged section and the conventional road section.

In a preferred embodiment of the invention, said plurality of box girders (for example a wide box girder and a narrow box girder) used to form the same widened box girder are measured before said T-connector is applied After the settlement value is reached, adjust the height of the support to make the two box girders at the same horizontal position, and then apply the T-shaped connector.

In the present invention, the term "settlement stability" means that the settlement is less than 1 mm within one month.

In another preferred example of the present invention, the T-shaped connector is cast from reinforced concrete. Prior to applying the T-shaped connector, two adjacent box girders (in a preferred example of the present invention, the adjacent two box girders are one of the wide box girder and one of the narrow box girders) are opposite to each other. The two surfaces are chiseled to improve the connection strength with the T-shaped connector.

C. The maintenance method of elevated road of the present invention

The maintenance method of the elevated road in the parallel parallel section of the present invention comprises the following steps:

1) Set the early warning value of column settlement; the early warning value depends on factors such as the material of the T-shaped connector. In a preferred example of the present invention, the warning value is set to 4mm.

2) Periodically measure the settlement difference of two or more columns used to support the same widened box girder; the period of settlement measurement is related to the local geological conditions, for example. Under geological conditions prone to subsidence, the frequency of subsidence measurement should be higher than that under geological conditions not prone to subsidence. In a preferred example of the present invention, the period of settlement measurement is set at three months.

3) When the settlement difference reaches the warning value, adjust the height of the support provided on the pillar to control the internal force of the plurality of box girders and the T-shaped connector. In a preferred example of the present invention, the support and the pillar are connected by bolts. Therefore, when the difference in settlement reaches the warning value, the bolts can be loosened, and the horizontal positional relationship between the multiple box girders can be adjusted with, for example, a jack, thereby eliminating the stress applied to the T-shaped connectors.

In a better example of the present invention, described maintenance method begins to continue to the whole process of project operation by pile foundation construction, promptly it comprises the following steps:

1) Observe the height of the column before erecting the upper structure;

2) Measure the settlement initial value of each column immediately after the erection of the upper structure is completed to form the ultra-wide box girder of the present invention, and then measure continuously for 3 times, each time at an interval of 1 month;

3) Measure the column settlement every quarter for 3 consecutive quarters;

4) Then measure the settlement value of the column once a year.

Below in conjunction with embodiment further illustrate the present invention.

Example 1

Set up a set of columns along the extension direction of the elevated road at the test site to simulate the situation of an on-ramp and slab section. A wide box girder with a width of 25 meters and a narrow box girder with a width of 8 meters are respectively hoisted on the columns. The distance between one end of the wide box girder and the end of the adjacent narrow box girder extending along its width direction is 4.5 meters.

Segmental box girders are assembled along the longitudinal bridge direction to form two elevated roads, wide and narrow, 4.5 meters apart.

Observe the settlement of the two elevated road box girders.

After the settlement is stable, T-shaped connectors are poured with reinforced concrete between the two formed elevated roads.

The load-carrying vehicle is used to simulate the daily conditions on the formed combined slab section to test the load-bearing performance of the box girder. After 6 months of testing, no cracks occurred in the box girder.

Example 2

Repeat the steps of Example 1, but the distance between one end of the wide box girder in the joint section and the end of the adjacent narrow box girder extending along its width direction is 0.5 meters. Results During the 6-month test period, no cracking of the box girder occurred.

The present invention has been described in detail above in conjunction with the situation of on-ramp. It should be understood, however, that the invention is also applicable to, for example, off-ramps, emergency parking areas and situations involving both on-ramps and on-ramps. In addition, those skilled in the art can easily make various changes and improvements after reading the disclosure of the present invention, and therefore, the present invention includes all such changes and improvements within the scope of the appended claims.

Claims (9)

1. A box girder (400), comprising two or more wide box girders (1) and/or narrow box girders (2) each having an upper surface of a bearing bridge deck, said wide box girder (1) And/or the narrow box girders (2) extend in a straight line in the transverse direction, and are characterized in that there is a T-shaped connector (3) between two laterally adjacent box girders, and the upper part of the T-shaped connector (3) One end (4) of the transverse part (6) is lapped on the upper surface of a box girder, and the other end (4') is lapped on the upper surface of another adjacent box girder, and its lower vertical part (5) fills The gap between the box girders. 2. The box girder according to claim 1, characterized in that the T-shaped connectors are assembled from steel structures or poured from reinforced concrete. 3. The box girder according to claim 1, characterized in that the height of the lower vertical part of the T-shaped connector is equal to the height of the ends of the wide box girder (1) and/or narrow box girder (2), so that The lower end of the lower vertical part of the T-shaped connector is aligned with the end of the wide box girder (1) or the narrow box girder (2). 4. An elevated road (100) for a parallel board section, which is composed of a parallel board board section (200) and a board board section (300) with a gradually changing width, The parallel paralleling section (200) includes a column (11), a widened horizontal box girder placed on the column (11) and a longitudinal box girder erected between the widened horizontal box girders, and is characterized in that The widened transverse box girder and longitudinal box girder are composed of the box girder (400) according to claim 1. 5. A method for manufacturing a board-end elevated road as claimed in claim 4, comprising the steps of: Form two or three uprights (11) extending along the road width at prescribed intervals according to the required road width; A wide box girder (1) and one or two narrow box girders (2) arranged transversely whose width extends into a straight line along the width of the road are respectively formed on the two or three columns (11). Both the wide box girder (1) and the narrow box girder (2) arranged laterally include an upper surface for carrying road slabs; Vertically arranged wide box girders (1) or narrow boxes are separately hoisted between two adjacent transversely arranged wide box girders (1) or adjacent two transversely arranged narrow box girders (2) along the extension direction of the elevated road Beam(2); A T-shaped connector (3) is formed between each pair of wide box girders (1) and narrow box girders (2) adjacent in the width direction of the elevated road, so that one end of the upper cross section of the T-shaped connector overlaps It is connected to the upper surface of the wide box girder, and the other end is lapped on the upper surface of the adjacent narrow box girder, so that the lower vertical part fills the gap between the wide box girder and the narrow box girder; thus forming a parallel parallel plate segment(200); and A doubling section (300) with a gradually changing width is formed. 6. The method according to claim 5, characterized in that forming the T-shaped connector (3) is performed after the wide box girder (1) and the narrow box girder (2) reach settlement stability. 7. method as claimed in claim 5 or 6, is characterized in that described T-shaped connector is poured by reinforced concrete; Before forming this T-shaped connector, earlier described wide box girder (1) and The two opposite surfaces of the narrow box girder (2) are chiseled to improve the fastness of connection with the T-shaped connection. 8. A method for maintaining elevated roads in parallel sections according to claim 4, comprising the steps of: 1) Set the column settlement warning value; 2) Regularly measure the settlement difference of columns used to carry the same box girder; 3) When the settlement difference reaches the early warning value, adjust the height of the support placed on the column to eliminate the wide box girder, the narrow box girder and the wide box girder and the narrow box girder. The internal force of the T-shaped connector between. 9. The method according to claim 8, characterized in that the column settlement warning value is set to 4mm.

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