CN100494576C - Erecting Method of Suspension Scaffold Outside the Box in Box Bridge Girder Maintenance Project - Google Patents

Abstract

The invention relates to a construction method of external scaffold in box-type bridge maintenance engineering, particularly a construction method of externally-suspended scaffold in maintenance engineering of box-type bridge girder. The invention is characterized in that the method comprises the following steps: 1) building a full hall scaffold, as a hoisting rooting platform, on a pier repair platform of the original bridge or in a smaller space near the pier, and building a first row of in-box horizontal steel tubes (8), vertical leaf steel cables (9), vertical right steel cables (10), low boom columns (13), left vertical steel tubes (12) and right vertical steel tubes (14) on the hoisting rooting platform; 2) cantilevering second and third rows by the same method as the first tow until the maintenance section is covered completely; 3) building trusses; 7) paving gang boards on a truss top chord (15), a left web maintenance platform (22) and a right web maintenance platform (23) respectively, and suspending a safety net. The invention has the advantages of no limitation of space under bridge and short construction cycle.

Description

Erecting Method of Suspension Scaffold Outside the Box in Box Bridge Girder Maintenance Project

technical field

The invention relates to a method for setting up scaffolding outside the box of a box-type bridge maintenance project.

Background technique

Scaffolding is an indispensable temporary facility in building construction. It is erected with the progress of the project and dismantled when the project is completed. Although scaffolding is a temporary facility, it is inseparable from scaffolding in the foundation of the project, main construction and decoration, equipment installation and other operations. Scaffolding is often used in construction to solve the problems of personnel operating platforms, temporary material storage and short-distance transportation channels. Therefore, whether the scaffolding design and construction is reasonable or not not only directly affects the construction progress and construction cost of the construction project, but also directly affects the working conditions and life safety of the operators.

A certain construction platform needs to be set up for new bridges and bridge reinforcement and maintenance. Conventional construction of new bridges mainly adopts the combination of cast-in-place support and hanging blue hanging cast-in-place. Conventional scaffolds are mainly floor-to-ceiling frames and sliding scaffolds, and the materials used are steel pipes, section steel and other materials. The advantages of conventional scaffolding construction are: the structural force is clear, safe and reliable; the disadvantages are: large site constraints, heavy weight, large amount of materials, high cost, and long construction period.

Due to factors such as space under the bridge and structures (river, railway) involved in bridge reinforcement and maintenance, the construction site does not have the conditions for erecting full-house scaffolding and sliding scaffolding, and the existing scaffolding construction methods are difficult to implement.

Contents of the invention

The object of the present invention is to provide a method for erecting a hanging scaffold outside the box of a box-type bridge girder body maintenance project that is not limited by the site under the bridge and has a short construction period.

In order to achieve the above object, the technical solution of the present invention is: the erection method of hanging scaffolding outside the case of box-type bridge girder body maintenance project, it is characterized in that it comprises the following steps:

1) Use the maintenance platform of a bridge pier of the original bridge or use the smaller site at the bridge pier to set up a full house of scaffolding as the hanger construction rooting platform, relying on the hanger construction rooting platform, set up the first row of horizontal steel pipes in the box 8, vertical Left steel wire rope 9, vertical right steel wire rope 10, truss lower chord 13, left vertical pole steel pipe 12, right vertical pole steel pipe 14:

At first along the transverse direction of the box bridge at the left part and the right part of the box girder bottom plate 5 of the box bridge girder body, the first row of left holes 6 and right holes 4 are opened. The first row of horizontal steel pipes 8 in the box is horizontally placed in the box girder cavity 2, and the vertical left steel wire rope 9 of the first row passes through the left hole 6 of the first row and hangs on the horizontal steel pipe 8 in the box. The two ends of the left steel wire rope 9 are fixedly connected by rope clamps to form a left steel wire rope cover. The vertical right steel wire rope 10 of the first row passes through the right hole 4 of the first row and hangs on the horizontal steel pipe 8 in the box. The two ends of the right steel wire rope 10 are fixedly connected by rope clamps 11 to form a right steel wire rope cover;

Pass the truss lower chord 13 of the first row through the left wire rope sleeve and the right wire rope sleeve of the first row; the upper end of the left pole steel pipe 12 passes through the left hole 6 and fixes it with the horizontal steel pipe 8 in the box of the first row by fasteners Connection, the lower end of the left vertical rod steel pipe 12 is fixedly connected with the lower chord 13 of the truss by a fastener, and the upper end of the right vertical rod steel pipe 14 passes through the right hole 4 and is fixedly connected with the horizontal steel pipe 8 in the first row of boxes by the fastener. The lower end of the right vertical rod steel pipe 14 is fixedly connected with the lower chord 13 of the truss by a fastener;

2) According to the method of erecting horizontal steel pipe 8, vertical left steel wire rope 9, vertical right steel wire rope 10, truss lower chord 13, left vertical rod steel pipe 12, right vertical rod steel pipe 14 in the first row, along the longitudinal direction of the box bridge, Set up the second row of horizontal steel pipes, vertical left steel wire ropes, vertical right steel wire ropes, truss lower chords, left vertical rod steel pipes, and right vertical rod steel pipes in the second row on the box girder floor 5; Set up the second row, the third row... until the maintenance section is completed;

3) The truss lower chord 13 of the first row is fixedly connected with the truss lower chord of the second row by the truss longitudinal lower link, and the truss lower chord of the second row and the third row of the truss lower chord are fixedly connected by the truss longitudinal lower chord Connecting rods are fixedly connected, and so on;

A truss upper chord 15 is erected above the truss lower chord, and the truss upper chord is fixedly connected with the left vertical rod steel pipe 12 and the right vertical rod steel pipe 14 by fasteners; the first row of truss upper chords and the second row of truss upper chords are connected by The longitudinal upper link is fixedly connected, the truss upper chord of the second row and the third row of truss upper chord are fixedly connected by the truss longitudinal upper link, and so on; the truss upper chord and the truss lower chord are respectively connected by truss vertical bars 1. Fixed connection of truss oblique rods; truss lower chords, truss upper chords, truss vertical rods, truss oblique rods, truss longitudinal lower links, and truss longitudinal upper links constitute the truss;

4) Extend the left web wire rope 16 from the left web ventilation hole 18 of the box girder left web 7 of the box girder body of the box bridge, and the lower end of the left web wire rope 16 is fixedly connected with the lower chord 13 of the truss, and the left web wire rope The upper end of 16 is located in the inner chamber 2 of the box girder, and is fixed by a steel pipe; the right web steel wire rope 17 is stretched out from the right web ventilation hole 19 of the box girder right web 3 of the box bridge girder body, and the right web steel wire rope 17 The lower end is fixedly connected with the lower chord 13 of the truss, and the upper end of the right web steel wire rope 17 is located in the inner cavity of the box girder and fixed by a steel pipe;

5) From the left hole 6 of the box girder bottom plate 5, extend an obliquely left steel wire rope 20, the lower end of the obliquely left steel wire rope 20 is fixedly connected with the lower chord 13 of the truss, and the upper end of the obliquely left steel wire rope 20 is located in the inner cavity 2 of the box girder, It is fixed by the horizontal steel pipe 8 in the box; the oblique right steel wire rope 21 is extended from the right hole 4 of the box girder bottom plate 5, and the lower end of the oblique right steel wire rope 21 is fixedly connected with the lower chord 13 of the truss, and the upper end of the oblique right steel rope 21 is located in the box Inside the beam cavity 2, it is fixed by the horizontal steel pipe 8 in the box;

6) A left web maintenance platform 22 is provided on the left side of the left web 7 of the box girder. The lower end of the left web maintenance platform 22 is fixedly connected with the truss upper chord 15 and the truss lower chord 13 by fasteners. The left web maintenance platform 22 The middle part is fixedly connected with one end of the left fixedly connected steel pipe 24 by a fastener, the other end of the left fixedly connected steel pipe 24 is fixedly connected with the left vertical rod steel pipe 12 by a fastener, and the top of the left web maintenance platform 22 is connected with the left web by a fastener. One end of the plate connection steel pipe 26 is fixedly connected, and the other end of the left web connection steel pipe 26 passes through the left web ventilation hole 18 and is fixed with the steel pipe located in the inner cavity 2 of the box girder by fasteners; the right side of the right web 3 of the box girder Set the right web maintenance platform 23, the lower end of the right web maintenance platform 23 is fixedly connected with the truss upper chord 15 and the truss lower chord 13 by fasteners, and the middle part of the right web maintenance platform 23 is fixedly connected with the right steel pipe 25 by fasteners One end of the right fixedly connected steel pipe 25 is fixedly connected with the right vertical rod steel pipe 14 by a fastener, and the top of the right web maintenance platform 23 is fixedly connected with an end of the right web connected steel pipe 27 by a fastener, and the right web The other end of the plate connecting steel pipe 27 passes through the vent hole 19 of the right web and is fixed with the steel pipe positioned in the inner cavity 2 of the box girder by fasteners;

7) The truss upper chord 15, the left web maintenance platform 22 and the right web maintenance platform 23 are respectively laid springboards, and the dense mesh safety net is hung under the truss upper chord 15; the left web maintenance platform 22 and the right web maintenance platform 23 are hung safe net.

Beneficial effects of the present invention:

1. During the bridge maintenance and construction process, because there are rivers, railways, and roads under the bridge and the shipping or traffic under the bridge cannot be interrupted, and there is no reliable rooting point for scaffolding under the bridge, or because the beam maintenance operation point is relatively high from the ground To save the cost of scaffolding, adopting the present invention can be used as a construction platform for maintenance and reinforcement outside the box of a box girder bridge body.

1) It is not restricted by the site under the bridge, does not interrupt the existing traffic under the bridge, and has a wide range of applications.

2) The structural form is safe and reliable, meeting the construction load requirements of maintenance projects.

3) Compared with the full house scaffolding and section steel bracket, the material consumption is less and more economical.

4) Short construction period.

5), set up the full scaffolding to the top of the bridge web, the full scaffolding is relatively high, so that the wind load has a greater impact on the full scaffolding; while the suspended scaffold of the present invention is attached to the bottom plate of the box girder, the height is small, and the structure has better wind resistance .

Description of drawings

Fig. 1 is the structural representation of horizontal steel pipe 8, vertical left steel wire rope 9, vertical right steel wire rope 10 in the present invention erecting box;

Fig. 2 is a structural schematic view of erecting the left vertical rod steel pipe 12, the lower chord 13 of the truss, and the right vertical rod steel pipe 14 in the present invention;

Fig. 3 is the structural representation of erecting truss of the present invention;

Fig. 4 is the structural representation of setting up left web steel wire rope 16, right web steel wire rope 17 of the present invention;

Fig. 5 is the structural representation of erecting obliquely left steel wire rope 20, obliquely right steel wire rope 21 of the present invention;

Fig. 6 is a schematic structural view of the erection of the present invention;

Fig. 7 is a schematic diagram of the longitudinal structure of the suspended scaffold erected by the present invention

In the figure: 1-top of box girder, 2-inner cavity of box girder, 3-right web of box girder, 4-right hole, 5-bottom plate of box girder, 6-left hole, 7-left web of box girder, 8- Horizontal steel pipe in the box, 9-vertical left steel wire rope, 10-vertical right steel wire rope, 11-rope clamp, 12-left vertical rod steel pipe, 13-truss lower chord, 14-right vertical rod steel pipe, 15-truss upper chord, 16-left web wire rope, 17-right web wire rope, 18-left web ventilation hole, 19-right web ventilation hole, 20-diagonal left wire rope, 21-diagonal right wire rope, 22-left web maintenance Platform, 23-right web maintenance platform, 24-left fixed connection steel pipe, 25-right fixed connection steel pipe, 26-left web connection steel pipe, 27-right web connection steel pipe, 28-first row, 29-second row, 30-box bridge, 31-river.

Detailed ways

As shown in Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, and Fig. 7, the erection method of hanging scaffolding outside the box-type bridge girder maintenance project box includes the following steps:

1) Use a bridge pier of the original bridge (such as the 13 ^# bridge pier of a certain bridge in Wuhan) to repair the platform or use the smaller site at the bridge pier to build a full house of scaffolding as a rooting platform for hanger construction, and expand and strengthen the maintenance platform according to the actual situation on site. To meet the requirements of material transportation; relying on the rooting platform of the hanger construction, set up the horizontal steel pipe 8 in the first row of boxes, the vertical left steel wire rope 9, the vertical right steel wire rope 10, the truss lower chord 13, the left vertical pole steel pipe 12, Right pole steel pipe 14:

First open the first row of left holes 6 and right holes 4 on the left and right parts of the box girder bottom plate 5 of the box bridge girder in the horizontal direction of the box bridge [such as the box girder bottom plate 5 having suitable holes (such as during cantilever construction) Boom hole) can omit the opening], horizontally place the first row of horizontal steel pipes 8 in the box in the box girder cavity 2, and the vertical left steel wire rope 9 of the first row passes through the left hole 6 of the first row The cover is hung on the horizontal steel pipe 8 in the box, the two ends of the vertical left steel wire rope 9 are fixedly connected by rope clamps to form the left steel wire rope cover, and the vertical right steel wire rope 10 of the first row passes through the cover through the right hole 4 of the first row. Hang on the horizontal steel pipe 8 in the box, and the two ends of the vertical right wire rope 10 are fixedly connected by rope clamps 11 to form a right wire rope cover;

Pass the truss lower chord 13 of the first row through the left wire rope sleeve and the right wire rope sleeve of the first row; the upper end of the left pole steel pipe 12 passes through the left hole 6 and fixes it with the horizontal steel pipe 8 in the box of the first row by fasteners Connection, the lower end of the left vertical rod steel pipe 12 is fixedly connected with the lower chord 13 of the truss by a fastener, and the upper end of the right vertical rod steel pipe 14 passes through the right hole 4 and is fixedly connected with the horizontal steel pipe 8 in the first row of boxes by the fastener. The lower end of the right vertical rod steel pipe 14 is fixedly connected with the lower chord 13 of the truss by a fastener;

2) According to the method of erecting horizontal steel pipe 8, vertical left steel wire rope 9, vertical right steel wire rope 10, truss lower chord 13, left vertical rod steel pipe 12, right vertical rod steel pipe 14 in the first row, along the longitudinal direction of the box bridge, Set up horizontal steel pipes, vertical left steel wire ropes, vertical right steel wire ropes, truss lower chords, left vertical rod steel pipes, right vertical rod steel pipes in the second row of box girder bottom plates 5; The second row, the third row, etc., cantilevered in the direction of ^#bridge pier (bridge longitudinal direction), until the maintenance section is completed;

3) The truss lower chords 13 of the first row are fixedly connected with the truss lower chords of the second row by the truss longitudinal lower links (fixed connection is realized by docking fasteners), the truss lower chords of the second row are connected with the third row The lower chords of the truss are fixedly connected by the longitudinal lower link of the truss (fixed connection is realized by butt fasteners), and so on;

A truss upper chord 15 is erected above the truss lower chord, and the truss upper chord is fixedly connected with the left vertical rod steel pipe 12 and the right vertical rod steel pipe 14 by fasteners; the first row of truss upper chords and the second row of truss upper chords are connected by The longitudinal upper link is fixedly connected (fixed connection by butt fasteners), the truss upper chords of the second row and the third row of truss upper chords are fixedly connected by truss longitudinal upper links (fixed connection is realized by butt fasteners), And so on; the truss upper chord and the truss lower chord are fixedly connected by the truss vertical rod and the truss diagonal rod respectively (fixed connection is realized by fasteners); the truss lower chord, the truss upper chord, the truss vertical rod, the truss diagonal rod, The longitudinal lower link and the longitudinal upper link of the truss constitute the truss;

4) Extend the left web wire rope 16 from the left web ventilation hole 18 of the box girder left web 7 of the box girder body of the box bridge, and the lower end of the left web wire rope 16 is fixedly connected with the lower chord 13 of the truss, and the left web wire rope The upper end of 16 is located in the inner chamber 2 of the box girder, and is fixed by a steel pipe; the right web steel wire rope 17 is stretched out from the right web ventilation hole 19 of the box girder right web 3 of the box bridge girder body, and the right web steel wire rope 17 The lower end is fixedly connected with the lower chord 13 of the truss, and the upper end of the right web steel wire rope 17 is located in the inner cavity 2 of the box girder and fixed by a steel pipe;

5) From the left hole 6 of the box girder bottom plate 5, protrude an oblique left steel wire rope 20 (or use an oblique steel pipe on the outside of the box girder bottom plate 5 to connect with the truss lower chord fastener), and the lower end of the oblique left steel wire rope 20 is connected to the lower chord of the truss The rod 13 is fixedly connected, and the upper end of the obliquely left steel wire rope 20 is located in the box girder cavity 2, and is fixed by the horizontal steel pipe 8 in the box; the obliquely right wire rope 21 is stretched out from the right hole 4 of the box girder bottom plate 5 (or in the box girder). The outer side of the base plate 5 is connected with the truss lower chord fastener with an oblique steel pipe), the lower end of the oblique right steel wire rope 21 is fixedly connected with the truss lower chord 13, and the upper end of the oblique right wire rope 21 is located in the inner cavity 2 of the box girder. Steel pipe 8 is fixed;

6) A left web maintenance platform 22 is provided on the left side of the left web 7 of the box girder (the left web maintenance platform 22 is connected by steel pipes and fasteners), and the lower end of the left web maintenance platform 22 is connected by fasteners and trusses. Rod 15 and truss lower chord 13 are fixedly connected, the middle part of the left web maintenance platform 22 is fixedly connected with one end of the left fixedly connected steel pipe 24 by a fastener, and the other end of the left fixedly connected steel pipe 24 is fixed with the left vertical rod steel pipe 12 by a fastener Connection, the top of the left web maintenance platform 22 is fixedly connected with one end of the left web connecting steel pipe 26 by a fastener, and the other end of the left web connecting steel pipe 26 passes through the left web ventilation hole 18 by the fastener and is located in the box girder The steel pipe in the cavity 2 is fixed; the right side of the box girder right web 3 is provided with a right web maintenance platform 23 (the right web maintenance platform 23 is connected by steel pipes and fasteners), and the lower end of the right web maintenance platform 23 is formed by The fastener is fixedly connected with the truss upper chord 15 and the truss lower chord 13. The middle part of the right web maintenance platform 23 is fixedly connected with one end of the right fixedly connected steel pipe 25 by the fastener, and the other end of the right fixedly connected steel pipe 25 is connected with the right side by the fastener. The vertical rod steel pipe 14 is fixedly connected, the top of the right web maintenance platform 23 is fixedly connected with one end of the right web connecting steel pipe 27 by a fastener, and the other end of the right web connecting steel pipe 27 passes through the right web ventilation hole 19 by a fastener It is fixed with the steel pipe located in the inner cavity 2 of the box girder;

7) The truss upper chord 15, the left web maintenance platform 22 and the right web maintenance platform 23 are respectively laid springboards, and the dense mesh safety net is hung under the truss upper chord 15; the left web maintenance platform 22 and the right web maintenance platform 23 are hung safe net. Component material quality requirements:

1. Steel pipe: Steel pipe should have a product quality certificate. Scaffolding steel pipe adopts No. 3 ordinary steel pipe specified in the current national standard "Straight Seam Electric Welded Steel Pipe" (GB/T 12793) or "Welded Steel Pipe for Low Pressure Fluid Transmission" (GB/T 3092), and its quality should meet the current national standard "Carbon Steel Pipe". The provisions of Q235-A grade steel in Plain Structural Steel (GB/T 700). The steel pipe adopts φ48*3.5, without severe bending, flattening, cracks, scarring, delamination, dislocation, hard bending, indentation and corrosion. The surface of the steel pipe should be straight and smooth and coated with anti-rust paint.

2. Steel wire rope: The setting of steel wire rope and rope clamp should be strictly selected according to the model specified in the scaffold calculation book.

3. Fasteners: no brittle cracks, deformation, and wire slipping, good mechanical properties and anti-rust treatment. The mechanical performance of fasteners conforms to the KT33-S technical standard stipulated in "GB-978-67".

4. Springboard: Use Nanzhu springboard with a length of 2.7m, a width of 25cm, and a thickness of 5cm, without loosening or slipping.

5. Safety net: Qualified polyvinyl chloride woven 1.8*6m dense-mesh safety net shall be selected for the railing fence, and the safety net shall be a dense-mesh safety net with a size of not less than 2000 mesh/100cm ² . Complete certificates and security inspection certificates are required. Scaffold erection and use safety requirements:

1. The operator of the suspended scaffold must be a professional scaffolder who has passed the assessment of the current national standard "Special Operator Safety Technology Assessment Management Rules" (GB5036), and holds a special post personnel certificate.

2. Personnel erecting suspended scaffolds must wear safety helmets, safety belts and non-slip shoes. Suspended scaffolding needs to hang safety nets while erecting.

3. The components and erection quality of the suspended scaffold shall be erected in strict accordance with the technical requirements of the construction specifications, and the distance and connection of each rod must meet the requirements. After the hanging scaffold is erected, it shall be inspected and accepted according to the "Technical Specifications for the Safety of Steel Pipe Scaffolding for Building Construction Fasteners" and the calculation book of the suspended scaffold, and it can only be used after passing the standard.

4. The number of construction workers and stacked materials on the construction platform of the suspended scaffold shall be strictly controlled according to the design load requirements, and shall not be overloaded. The construction load on the scaffold should be evenly arranged, and should not be concentrated on one side, resulting in one-way eccentric force. It is strictly forbidden to hang lifting equipment on each rod of the suspended scaffold.

5. During the construction process, set up specialized technical personnel to inspect the main hanging points and connecting fasteners of the hanging scaffold. Removal of suspended scaffolding:

1. Scaffolding should be dismantled in time after completing its function. When dismantling the scaffolding, first remove the rubbish and sundries on the scaffolding, and it is strictly forbidden to throw it downward. The work area should be divided when the shelf is dismantled, and a warning line and obvious signs should be set up during the dismantling.

2. The dismantling of scaffolding is just the opposite of the order of erection, dismantling after erection, and dismantling after erection.

3. The dismantling of scaffolding must be carried out step by step. According to the principle of top-down, the dismantling shall be carried out step by step. It cannot be dismantled in two or more steps at the same time. If necessary, temporary support can be erected during dismantling. When dismantling in sections, the height difference should not be greater than two steps. If the height difference is greater than two steps, it shall be reinforced according to the opening of the scaffold. The connection between the climbing facilities, scaffolding and bridge body will be dismantled simultaneously with the scaffolding.

Claims (1)

1. the erection method of the outer boat scaffold of box-type bridge beam body maintenance works case is characterized in that it comprises the steps:

1) utilize a bridge pier inspection platform of former bridge or utilize the place at bridge pier place set up full hall scaffold as suspension bracket the construction platform of taking root, with this suspension bracket construction platform of taking root is support, sets up horizontal steel tube (8), vertical left wire rope (9), vertical right wire rope (10), truss lower chord (13), left pole steel tube (12), right pole steel tube (14) in first row's the case:

At first along box-type bridge laterally at the left part of the case beam base plate (5) of box-type bridge beam body, right part is opened the first row left hole (6), right hole (4), horizontal steel tube (8) in first case of arranging is laterally placed on the edge in case beam inner chamber (2), first row's vertical left wire rope (9) passes cover and hangs on the interior horizontal steel tube (8) of case from first row's left hole (6), the two ends of vertical left wire rope (9) constitutes left steel wire loop by rope clamp is fixedly connected, first row's vertical right wire rope (10) passes cover and hangs on the interior horizontal steel tube (8) of case from first row's right hole (4), the two ends of vertical right wire rope (10) is by the right steel wire loop of the fixedly connected formation of rope clamp (11);

First row's truss lower chord (13) is passed first row's left steel wire loop, right steel wire loop; The upper end of left side pole steel tube (12) is passed left hole (6) and is fixedlyed connected with horizontal steel tube (8) in the case that first arranges by fastener, fixedlyed connected with truss lower chord (13) by fastener in the bottom of left side pole steel tube (12), the upper end of right pole steel tube (14) is passed right hole (4) and is fixedlyed connected with horizontal steel tube (8) in first case of arranging by fastener, is fixedlyed connected with truss lower chord (13) by fastener in the bottom of right pole steel tube (14);

2) by the method for horizontal steel tube (8), vertical left wire rope (9), vertical right wire rope (10), truss lower chord (13), left pole steel tube (12), right pole steel tube (14) in the case of setting up first row, along box-type bridge vertically horizontal steel tube, vertical left wire rope, vertical right wire rope, truss lower chord, left pole steel tube, right pole steel tube in case beam base plate (5) is set up second row's case; Progressively set up second row, the 3rd row to another adjacent bridge pier direction cantilever ..., until till needing the maintenance works section intact;

3) fixedlyed connected by the vertical lower link of truss between first row's truss lower chord (13) and second row's the truss lower chord, fixedlyed connected by the vertical lower link of truss between second row's truss lower chord and the truss lower chord that the 3rd arranges, the rest may be inferred;

Pricncipal rafter (15) is set up in the top of truss lower chord, and pricncipal rafter is fixedlyed connected by fastener with left pole steel tube (12), right pole steel tube (14); Vertically go up connecting rod by truss between first pricncipal rafter of arranging and the second row's pricncipal rafter and fixedly connected, vertically go up connecting rod by truss between second row's pricncipal rafter and the 3rd row's pricncipal rafter and fixedly connected, the rest may be inferred; Fixedly connected by vertical bar of truss, truss brace respectively between pricncipal rafter and the truss lower chord; Truss lower chord, pricncipal rafter, vertical bar of truss, truss brace, the vertical lower link of truss, truss are vertically gone up connecting rod and are constituted truss;

4) from the left web gravity vent (18) of the case beam of box-type bridge beam body left side web (7), stretch out left web wire rope (16), fixedly connected with truss lower chord (13) in the lower end of left side web wire rope (16), the upper end of left side web wire rope (16) is positioned at case beam inner chamber (2), is fixed by steel pipe; From the right web gravity vent (19) of the right web of the case beam of box-type bridge beam body (3), stretch out right web wire rope (17), fixedly connected with truss lower chord (13) in the lower end of right web wire rope (17), the upper end of right web wire rope (17) is positioned at case beam inner chamber (2), is fixed by steel pipe;

5) from the left hole (6) of case beam base plate (5), stretch out oblique left wire rope (20), fixedly connected with truss lower chord (13) in the lower end of oblique left wire rope (20), the upper end of oblique left wire rope (20) is positioned at case beam inner chamber (2), and is fixing by horizontal steel tube in the case (8); From the right hole (4) of case beam base plate (5), stretch out oblique right wire rope (21), fixedly connected with truss lower chord (13) in the lower end of oblique right wire rope (21), the upper end of oblique right wire rope (21) is positioned at case beam inner chamber (2), and is fixing by horizontal steel tube in the case (8);

6) left web maintenance platform (22) is established in the left side of case beam left side web (7), the bottom of left side web maintenance platform (22) is by fastener and pricncipal rafter (15), truss lower chord (13) is fixedly connected, the middle part of left side web maintenance platform (22) is fixedly connected with a left end of fixedlying connected steel pipe (24) by fastener, the other end of the fixedly connected steel pipe in a left side (24) is fixedlyed connected with left pole steel tube (12) by fastener, the top of left side web maintenance platform (22) is fixedly connected by fastener is connected steel pipe (26) with left web a end, and the other end of left web connection steel pipe (26) passes left web gravity vent (18) and fixed by fastener and the steel pipe that is positioned at case beam inner chamber (2); Right web maintenance platform (23) is established on the right side of the right web of case beam (3), the bottom of right web maintenance platform (23) is by fastener and pricncipal rafter (15), truss lower chord (13) is fixedly connected, the middle part of right web maintenance platform (23) is fixedly connected with a right end of fixedlying connected steel pipe (25) by fastener, the other end of right fixedly connected steel pipe (25) is fixedlyed connected with right pole steel tube (14) by fastener, the top of right web maintenance platform (23) is fixedly connected by fastener is connected steel pipe (27) with right web a end, and the other end of right web connection steel pipe (27) passes right web gravity vent (19) and fixed by fastener and the steel pipe that is positioned at case beam inner chamber (2);

7) hang close order safety net below pricncipal rafter (15), the left web maintenance platform (22) and lay springboard respectively above the right web maintenance platform (23), pricncipal rafter (15); Left side web maintenance platform (22), right web maintenance platform (23) are hung safety net.

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