CN205205685U - Span wire pier is function portal device at most - Google Patents

Abstract

The utility model provides a multifunctional gantry device at the top of a suspension bridge pier, which belongs to the field of suspension bridge construction devices, and includes an existing gantry body. The existing gantry body includes a supporting truss system and a working platform, and the upper end of the working platform and the supporting truss system Connection, the lower end of the supporting truss system is anchored to the top of the suspension pier through the anchor system. The existing gantry body also includes the catwalk saddle, lifting system and traction system. system connection. The multifunctional gantry device on the top of the suspension bridge pier is equipped with the existing gantry body, the gantry is divided into blocks, and assembled on the top of the tower, which can not only meet the requirements of on-site hoisting, but also facilitate transportation, installation, and processing, and realize simplified construction and installation. , can be combined with the catwalk cable saddle at the top of the tower, which is safe under force, and can give full play to the role of the portal frame at all stages of the installation and construction of the upper structure of the suspension bridge, truly realizing a multi-purpose.

Description

Multifunctional gantry device on top of suspension bridge pier

technical field

The utility model relates to the field of suspension bridge construction devices, in particular to a multifunctional portal frame device at the top of a suspension bridge pier.

Background technique

In order to meet the lifting and installation of the main cable saddle, it is convenient for the construction of catwalks, traction systems, cable strand tensioning systems and other temporary facilities, as well as the installation of construction equipment such as cable tightening machines, wire winding machines, and cable cranes, and at the same time facilitates the subsequent erection of the main cable , cable clips and slings, steel box girders and other permanent structures, and a door frame is set on the top of the tower. Because the overall weight of the conventional door frame is too large, it is not conducive to hoisting and installation. It is necessary to simplify the design of the door frame to facilitate hoisting, installation, and transportation.

Utility model content

The utility model provides a multifunctional gantry device on the top of a suspension bridge pier, aiming at improving the above problems.

The utility model is achieved in that:

A multifunctional gantry device on the top of a suspension bridge pier, comprising a ready-to-install gantry body, the ready-to-install gantry body including a supporting truss system and a working platform, the working platform is connected to the upper end of the supporting truss system, and the supporting The lower end of the truss system is anchored to the top of the suspension bridge pier through an anchor system. The existing gantry body also includes a catwalk cable saddle, a lifting system and a traction system. The catwalk cable saddle, the lifting system and the traction system The system is respectively connected with the support truss system.

Further, the supporting truss system includes two oppositely arranged gantry truss structures, the two gantry truss structures are connected by several gantry beams, and the gantry truss structures include a plurality of main bearing columns, Longitudinal beams, several cross braces, several small diagonal braces and overhanging large diagonal braces, the main bearing column is anchored to the top of the suspension pier through the anchor system, the working platform is set on the longitudinal beams, two adjacent The main bearing column is connected by the cross brace and the small diagonal brace, one end of the longitudinal beam is a cantilever beam, and the cantilever beam is connected with the main bearing column by a cantilevered large diagonal brace. The cantilever beam and the cantilevered large diagonal brace are connected through the cross brace and the small diagonal brace.

The supporting truss system includes main bearing columns, longitudinal beams, cross braces and other components, which provide lifting and support for the installation and lifting of cable saddles, the erection and traction of cable strands, and the installation of steel box girder hoisting equipment. The supporting truss system adopts the gantry truss structure, and the overall structure of the supporting truss system is safe under force. The connection between each component is mainly bolted and supplemented by welding, which simplifies the difficulty of construction and facilitates transportation and turnover. It is made of standard profiles, bolted connections, fast assembly speed, high installation accuracy, and less on-site welding work.

Further, the gantry beams include end beams, inter-column beams, middle beams and cantilever beams, the two ends of the two longitudinal beams are respectively connected by the end beams, and the two longitudinal beams are connected to the The joints of the main bearing columns are connected by inter-column crossbeams, the middle parts of the two longitudinal beams are connected by middle crossbeams, and the two cantilever beams are connected by the inter-cantilever crossbeams.

By setting the end beams, column beams, middle beams and cantilever beams, multiple corresponding parts of the two longitudinal beams are connected, the structure is more stable, the force is safer, and the portal frame is fully utilized for all stages of the installation and construction of the suspension bridge superstructure. role.

Further, the end beams and the longitudinal beams, and the inter-column beams and the longitudinal beams are respectively connected by top diagonal braces.

The connection between the end beam and the longitudinal beam, and the inter-column beam and the longitudinal beam is strengthened by setting the top diagonal brace, which further improves the overall structural stability of the supporting truss system, strengthens the supporting function, and makes the overall stress more secure.

Further, the end beam is connected to the main load-bearing column at the end far away from the cantilever beam through a cross-bridge diagonal brace.

By setting the diagonal bracing of the transverse bridge, the bearing capacity of the transverse bridge is enhanced, the force is safer, and the structure is more reliable.

Further, the anchoring system includes embedded bolts, connecting steel plates, leveling nuts and reinforcing steel bars, the connecting steel plates are provided with bolt holes, and the main bearing column is anchored to the On the top of the suspension bridge pier, the leveling nuts and the reinforcing steel bars are respectively arranged on the main bearing column.

The main load-bearing column is anchored to the top of the suspension pier by connecting steel plates and embedded bolts. Therefore, the anchoring system adopts embedded bolts, connecting steel plates, leveling nuts and reinforcing steel bars, etc., to ensure the pressure, tension, torsion and wind resistance of the mast device.

Further, the catwalk cable saddle is connected to the main bearing column. The setting of embedded parts in the concrete on the top of the tower is reduced.

Further, the lifting system includes a lifting beam, a beam moving track, a traversing chain and a pulley block, the beam moving track is arranged on the longitudinal beam, and the lifting beam is installed across the beam moving track, The lifting beam is connected to the shifting trolley, and the traversing chain and the pulley block are respectively fixed on the cross braces on the cantilever beam.

The hoisting and vertical and horizontal movement of components of various tonnages are completed by various tonnage hoists installed on the top of the mast or on the ground. It is convenient and quick to move, easy to transport, install and process. The beam moving track ensures that the shifting trolley moves longitudinally along the existing track. Manual vertical displacement of the lifting beam can be realized by moving the chain and the pulley block laterally.

Further, the traction system includes a guide wheel set fixing frame, a winch support base and a block block, the guide wheel set fixation frame is arranged at the end of the longitudinal beam away from the cantilever beam, and the winch support base is installed on On the longitudinal beam, the pulley block is installed on the longitudinal beam at a position close to the support base of the hoist.

During the catway cable traction and cable strand erection process, ensure that the cable body passes smoothly, and use the hoist and pulley group to lift the cable strand to adjust the sag and line shape.

Further, the working platform is provided with a working platform guardrail. By setting the guardrail of the working platform, the personal safety of the construction personnel can be guaranteed and accidents such as falling can be prevented.

The beneficial effect of the multifunctional gantry device on the top of the suspension bridge pier provided by the utility model is: the multifunctional gantry device on the top of the suspension bridge pier is optimized on the traditional gantry system, and the gantry is divided into blocks by setting the existing gantry body , assembled at the top of the tower, and by setting the lifting system and traction system, it can not only meet the requirements of on-site hoisting, but also facilitate transportation, installation and processing, realize simplified construction and installation, and can be combined with the catwalk on the top of the tower. together. The gantry system structure is safe under force, and the gantry can give full play to the role of the gantry in all stages of the installation and construction of the suspension bridge superstructure, and truly realizes a multi-purpose.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following drawings will be briefly introduced in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention. Therefore, it should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained according to these drawings without creative work.

Figure 1 is a schematic diagram of the overall structure of the multifunctional gantry device on the top of the pier of the suspension bridge provided by the embodiment of the utility model;

Fig. 2 is a schematic diagram of the front view of the supporting truss system of the multifunctional gantry device on the top of the pier of the suspension bridge provided by the embodiment of the utility model;

Fig. 3 is a side view structural schematic diagram of the supporting truss system of the multifunctional gantry device on the top of the suspension bridge pier provided by the embodiment of the utility model;

Fig. 4 is a top view structural schematic diagram of the supporting truss system of the multifunctional gantry device on the top of the suspension bridge pier provided by the embodiment of the utility model;

Fig. 5 is a partial enlarged view of the multifunctional gantry device at the top of the pier of the suspension bridge provided by the embodiment of the utility model at a in Fig. 2;

Fig. 6 is a partial enlarged view of the multi-functional gantry device at the top of the pier of the suspension bridge provided by the embodiment of the utility model at b in Fig. 3;

Fig. 7 is a jigsaw diagram of the truss structure of the gantry truss structure of the multifunctional gantry device on the top of the suspension bridge pier provided by the embodiment of the utility model.

The marks in the figure are:

Working platform 101; suspension bridge pier top 102; catwalk turning cable saddle 103; portal truss structure 104; main bearing column 105; longitudinal beam 106; cross brace 107; Beam 110; end beam 111; column beam 112; middle beam 113; cantilever beam 114; top diagonal brace 115; cross bridge diagonal brace 116; embedded bolt 117; connecting steel plate 118; leveling nut 119; reinforcement bar 120; lifting beam 121; beam moving track 122; block pulley 123; guide wheel block 124; winch 125;

detailed description

In order to meet the lifting and installation of the main cable saddle, it is convenient for the construction of catwalks, traction systems, cable strand tensioning systems and other temporary facilities, as well as the installation of construction equipment such as cable tightening machines, wire winding machines, and cable cranes, and at the same time facilitates the subsequent erection of the main cable , cable clips and slings, steel box girders and other permanent structures, and a door frame is set on the top of the tower. Because the overall weight of the conventional door frame is too large, it is not conducive to hoisting and installation. It is necessary to simplify the design of the door frame to facilitate hoisting, installation, and transportation.

In view of this, the designer of the utility model has designed a multifunctional gantry device on the top of a suspended bridge pier through long-term exploration and attempts, as well as many experiments and efforts, and has designed a multifunctional gantry device on the top of a suspended bridge pier. The mast is divided into blocks and assembled on the top of the tower, and by setting up the lifting system and traction system, it can not only meet the requirements of on-site hoisting, but also facilitate transportation, installation and processing, and realize simplified construction and installation. Road turning cable saddle 103 is combined together. The gantry system structure is safe under force, and the gantry can give full play to the role of the gantry in all stages of the installation and construction of the suspension bridge superstructure, and truly realizes a multi-purpose.

In order to make the purpose, technical solutions and advantages of the embodiments of the utility model more clear, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described The embodiments are some embodiments of the present utility model, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Example

Please refer to Figures 1 to 4, the present embodiment provides a multifunctional gantry device at the top of a suspension bridge pier. The multifunctional gantry device at the top of a suspension bridge pier includes an existing gantry body, which includes a support truss system The working platform 101 is connected to the upper end of the supporting truss system, and the lower end of the supporting truss system is anchored to the top of the suspension bridge pier 102 through the anchor system. The catwalk turning saddle 103, the hoisting system and the traction system are respectively connected with the support truss system.

The multifunctional gantry device on the top of the suspension bridge pier provided in this embodiment is optimized on the traditional gantry system. By setting the ready-to-install gantry body, the gantry is divided into blocks and assembled on the top of the tower, and by setting the lifting system and traction The system can not only meet the requirements of on-site hoisting, but also facilitate transportation, installation and processing, realize simplified construction and installation, and can be combined with the catwalk saddle 103 at the top of the tower. The gantry system structure is safe under force, and the gantry can give full play to the role of the gantry in all stages of the installation and construction of the suspension bridge superstructure, and truly realizes a multi-purpose.

On the basis of the technical solution of the multifunctional gantry device on the top of the suspension bridge pier provided in the above embodiment, please refer to Figures 1 to 4 and 7, the supporting truss system includes two oppositely arranged gantry truss structures 104 , two gantry truss structures 104 are connected by several gantry beams, and the gantry truss structure 104 includes multiple main bearing columns 105, longitudinal beams 106, several cross braces 107, several small diagonal braces 108 and cantilevered large diagonal braces 109, the main load-bearing column 105 is anchored to the top of the suspension bridge pier 102 through the anchor system, the working platform 101 is set on the longitudinal beam 106, and two adjacent main load-bearing columns 105 are connected by cross braces 107 and small diagonal braces 108, and one end of the longitudinal beam 106 The cantilever beam 110 is connected to the main bearing column 105 through a cantilevered large diagonal brace 109 , and the cantilever beam 110 and the cantilevered large diagonal brace 109 are connected through a cross brace 107 and a small diagonal brace 108 .

The supporting truss system includes main bearing columns 105, longitudinal beams 106, cross braces 107 and other components to provide lifting and support for the installation and lifting of cable saddles, the erection and traction of cable strands, and the installation of steel box girder hoisting equipment. The supporting truss system adopts the gantry truss structure 104, and the overall structure of the supporting truss system is safe under force. The connection between each component is mainly bolted and supplemented by welding, which simplifies the difficulty of construction and facilitates transportation and turnover. It is made of standard profiles, bolted connections, fast assembly speed, high installation accuracy, and less on-site welding work.

As a preference, the existing gantry body of the gantry device is 8.8m high and 4.9m wide, and is designed as a large cantilever structure along the direction of the bridge, with a cantilever length of 13m.

Please refer to Fig. 4, the gantry crossbeam comprises end crossbeam 111, inter-column crossbeam 112, middle crossbeam 113 and cantilever crossbeam 114, and the two ends of two longitudinal beams 106 are respectively connected by end crossbeam 111, and two longitudinal beams 106 are connected with it The joints of the main bearing columns 105 are connected by an inter-column crossbeam 112 , the middle parts of the two longitudinal beams 106 are connected by a middle crossbeam 113 , and the two cantilever beams 110 are connected by an inter-cantilever crossbeam 114 .

By setting the end beams 111, the inter-column beams 112, the middle beams 113 and the cantilever beams 114, multiple corresponding parts of the two longitudinal beams 106 are connected, the structure is more stable, and the force is safer. stage to give full play to the role of the mast.

Referring to FIG. 4 , the end beams 111 and the longitudinal beams 106 , and the inter-column beams 112 and the longitudinal beams 106 are respectively connected by top braces 115 .

By setting the top diagonal brace 115, the connection between the end beam 111 and the longitudinal beam 106, and the inter-column beam 112 and the longitudinal beam 106 is strengthened, the overall structural stability of the supporting truss system is further improved, and the supporting function is strengthened. The force is more secure.

Please refer to FIG. 3 , the end beam 111 is connected to the main bearing column 105 at the end far away from the cantilever beam 110 through a cross-bridge diagonal brace 116 .

By arranging the diagonal braces 116 in the direction of the transverse bridge, the bearing capacity in the direction of the transverse bridge is enhanced, the stress is safer, and the structure is more reliable.

Please refer to Figures 1 to 3, Figures 5 and 6. The anchoring system includes embedded bolts 117, connecting steel plates 118, leveling nuts 119, and reinforcement bars 120. Bolt holes are provided on the connecting steel plates 118, and the main bearing columns 105 are connected through Steel plates 118 and pre-embedded bolts 117 are anchored to the pier top 102 of the suspension bridge, and leveling nuts 119 and reinforcing steel bars 120 are respectively arranged on the main bearing column 105 .

The main bearing column 105 is anchored to the suspension pier top 102 by connecting the steel plate 118 and the embedded bolt 117 , the reinforcing steel bar 120 plays a strengthening role, and the main bearing column 105 can be leveled by the leveling nut 119 . Therefore, the anchoring system adopts embedded bolts 117, connecting steel plates 118, leveling nuts 119, and reinforcing steel bars 120, etc., to ensure the pressure, tension, torsion, and wind resistance of the gantry device.

Please refer to FIG. 1 , the catwalk turning saddle 103 is connected with the main bearing column 105 . The setting of embedded parts in the concrete on the top of the tower is reduced.

Referring to Fig. 1, the lifting system includes a lifting beam 121, a beam moving track 122, a traversing chain and a pulley block 123. The crossbeam 121 is connected with the shifting trolley, and the traverse down chain and the pulley block 123 are respectively fixed on the cross braces 107 on the cantilever beam 110 .

The hoisting machines 125 of various tonnages arranged on the top of the mast or on the ground complete the lifting and vertical and horizontal movement of components of various tonnages. It is convenient and quick to move, easy to transport, install and process. The crossbeam moving track 122 ensures that the shifting trolley moves longitudinally along the existing track. By traversing the chain and the pulley block 123, the longitudinal displacement of the lifting beam 121 can be realized manually.

Please refer to Fig. 1, the traction system includes a guide wheel set fixing frame, a hoist support seat and a pulley block, the guide wheel set fixing frame is arranged on the end of the longitudinal beam 106 away from the cantilever beam 110, and the guide wheel set fixing frame is used for installing the guide wheel set 124, the winch support seat is installed on the longitudinal beam 106, and the block block is installed on the longitudinal beam 106 near the position of the winch support seat. The winch 125 is installed on the support base of the winch and connected with the traction cable 127 on the ground.

During the catway cable traction and cable strand erection process, the cable body is guaranteed to pass smoothly, and the hoist 125 and the pulley group are used to lift the cable strands to adjust the sag and line shape.

Referring to FIGS. 1-4 , the working platform 101 is provided with a working platform guardrail 126 . By setting the working platform guardrail 126, the personal safety of construction personnel can be ensured, and accidents such as falling can be prevented.

Key points for the installation and construction of the door frame device:

1. Each gantry is composed of two trusses and transverse connections. In the processing plant, the gantry is divided into several small processing rod units. After trial assembly, it will be shipped to the site for installation.

2. During the installation of the mast, according to the lifting capacity of the tower crane at the cable tower and the on-site assembly conditions of the mast, assemble the block components on the ground to reduce the workload of high-altitude installation. The weight of each component shall not exceed the maximum lifting capacity of the tower crane.

3. The installation of the door frame is carried out in two steps: one installation before the installation of the cable saddle, except for the rods in the longitudinal movement area of the door frame top flat car, all other components are installed in place at one time; after the installation of the cable saddle, complete the door frame system to form a complete structure.

4. After the gantry assembly before the cable saddle hoisting is completed, install hoist 125 and other equipment on the longitudinal beam 106 on the top surface of the gantry, and inspect and test the entire gantry system to ensure that all machinery and equipment are in good condition. It can be put into use only after it can work safely and normally.

5. During the construction period, pay attention to the weather forecast and avoid construction under weather conditions beyond the design conditions.

6. All construction shall comply with the design and on-site supervision requirements.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", Orientation indicated by "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. The positional relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the referred equipment or elements must have a specific orientation, be constructed and operated in a specific orientation , so it cannot be interpreted as a limitation of the present utility model.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present utility model, "plurality" means two or more, unless otherwise specifically defined.

In this utility model, unless otherwise specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connection, or integration; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present utility model according to specific situations.

In the present invention, unless otherwise clearly specified and limited, a first feature being "on" or "below" a second feature may include direct contact between the first and second features, and may also include the first and second features being in direct contact with each other. The features are not in direct contact but through another feature between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

The above descriptions are only preferred embodiments of the utility model, and are not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (10)

1. suspension cable bridge pier function mast apparatus at most, it is characterized in that, comprise existing dress door frame body, the described door frame body that now fills comprises sub-truss system and working platform, described working platform is connected with the upper end of described sub-truss system, the lower end of described sub-truss system is anchored in suspension cable top of bridge pier by anchor system, described now dress door frame body also comprises cat road and turns cable saddle, Hoisting System and trailer system, and described cat road turns cable saddle, described Hoisting System and described trailer system and is connected with described sub-truss system respectively.

2. suspension cable bridge pier according to claim 1 function mast apparatus at most, it is characterized in that, described sub-truss system comprises two door frame purlin chip architectures be oppositely arranged, two described door frame purlin chip architectures are connected by some door frame crossbeams, described door frame purlin chip architecture comprises many main carrying columns, longeron, some stulls, some little diagonal braces and large diagonal brace of encorbelmenting, described main carrying column is anchored in suspension cable top of bridge pier by described anchor system, described working platform is arranged on described longeron, adjacent two described main carrying columns are connected with described little diagonal brace by described stull, one end of described longeron is Cantilever Beams, described Cantilever Beams is connected by large diagonal brace of encorbelmenting with described main carrying column, described Cantilever Beams is connected with described little diagonal brace by described stull with described large diagonal brace of encorbelmenting.

3. suspension cable bridge pier according to claim 2 function mast apparatus at most, it is characterized in that, described door frame crossbeam comprises crossbeam between end floor beam, intercolumniation crossbeam, middle cross beam and cantilever, the two ends of two described longerons connect respectively by described end floor beam, two described longerons are connected by intercolumniation crossbeam in its junction with described main carrying column, the middle part of two described longerons is connected by middle cross beam, and two described Cantilever Beams are connected by crossbeam between described cantilever.

4. suspension cable bridge pier according to claim 3 function mast apparatus at most, is characterized in that, between described end floor beam with described longeron, described intercolumniation crossbeam is connected respectively by end face diagonal brace with between described longeron.

5. suspension cable bridge pier according to claim 4 function mast apparatus at most, is characterized in that, is connected between described end floor beam and the described main carrying column of the one end away from described Cantilever Beams by direction across bridge diagonal brace.

6. suspension cable bridge pier according to claim 2 function mast apparatus at most, it is characterized in that, described anchor system comprises pre-embedded bolt, junction steel plate, leveling nut and stiffener, described junction steel plate is provided with bolt hole, described main carrying column is anchored in suspension cable top of bridge pier by described junction steel plate and described pre-embedded bolt, and described leveling nut and described stiffener are arranged on described main carrying column respectively.

7. suspension cable bridge pier according to claim 2 function mast apparatus at most, is characterized in that, described cat road turns cable saddle and is connected with described main carrying column.

8. suspension cable bridge pier according to claim 2 function mast apparatus at most, it is characterized in that, described Hoisting System comprises lifting crossbeam, cross beam movement track, traversing jack and assembly pulley, described cross beam movement track is arranged on described longeron, described lifting crossbeam is across being installed in described cross beam movement track, described lifting crossbeam is connected with displacement dolly, and described traversing jack and described assembly pulley are individually fixed in the described stull on described Cantilever Beams.

9. suspension cable bridge pier according to claim 2 function mast apparatus at most, it is characterized in that, described trailer system comprises guide wheel group fixed mount, hoist engine supporting seat and tackle pulley, described guide wheel group fixed mount is arranged at described longeron one end away from described Cantilever Beams, described hoist engine supporting seat is installed on described longeron, and described tackle pulley is installed on the position near described hoist engine supporting seat on described longeron.

10. suspension cable bridge pier according to claim 1 function mast apparatus at most, is characterized in that, described working platform is provided with working platform guardrail.