CN112681135A

CN112681135A - Construction method of n-shaped sea-crossing temporary steel trestle

Info

Publication number: CN112681135A
Application number: CN202011475244.7A
Authority: CN
Inventors: 李宏强; 吴青华; 任高峰; 朱清利; 陈国庆; 王�锋; 唐辉
Original assignee: Third Engineering Co Ltd of China Railway 20th Bureau Group Co Ltd
Current assignee: Third Engineering Co Ltd of China Railway 20th Bureau Group Co Ltd
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2021-04-20
Anticipated expiration: 2040-12-14
Also published as: CN112681135B

Abstract

The invention discloses a construction method of a temporary steel trestle shaped across the sea, which comprises the following steps: firstly, constructing an abutment and a steel approach bridge; secondly, constructing two connecting bridge sections; thirdly, constructing two transition bridge sections; and fourthly, constructing the main bridge section. According to the invention, the inverted V-shaped sea-crossing temporary steel trestle is erected across the sea under the condition of combining the geographical positions of the existing wharf, the first dam and the second dam, the steel trestle main body and the channel-type trestle can provide a safe and reliable construction platform for the construction of the bridge to be built, the construction method of the temporary steel trestle is simple and convenient, the construction is convenient, the problem of difficulty in construction of the temporary steel trestle in the ultra-large span sea area is solved, and the construction period can be shortened.

Description

Construction method of n-shaped sea-crossing temporary steel trestle

Technical Field

The invention belongs to the technical field of temporary steel trestle construction, and particularly relates to a construction method of an n-shaped sea-crossing temporary steel trestle.

Background

The bridge to be built comprises a main bridge to be built, a first approach bridge to be built and a second approach bridge to be built, the total length of the bridge to be built is 1775.8m, the total length of the first approach bridge to be built is 720m, the total length of the second approach bridge to be built is 600m, for the second approach bridge to be built and the first approach bridge to be built with the total length of more than 500m, according to the actual engineering situation and the overall construction arrangement, a temporary steel trestle needs to be laid between the east and west banks along the direction of the bridge to be built during the construction process, and the temporary steel trestle has many unpredictable problems during the actual construction process, for example, because the temporary steel trestle needs to be laid in the direction matched with the bridge to be built, the first approach bridge to be built and the second approach bridge to be built at the set positions of the main span bridge to be built, the first approach bridge to be built and the second approach bridge to be built, meanwhile, the laying direction of the temporary steel trestle is required to be matched with the first approach bridge cofferdam structure to be built and the second approach bridge cofferdam structure to be built; moreover, due to the fact that the geographical position of the bridge to be built is complex, the construction requirements cannot be met by a conventional construction method, the large-scale pile foundation steel trestle is long in design and construction period and high in construction cost, rapid construction cannot be achieved, and the requirements of economy, applicability and environmental protection and conservation cannot be met. Therefore, it is required to provide a construction method of the n-shaped sea-crossing temporary steel trestle which is convenient for rapid construction.

Disclosure of Invention

The invention aims to solve the technical problem that the defects in the prior art are overcome, and the invention provides the construction method of the n-shaped sea-crossing temporary steel trestle, which is characterized in that the n-shaped sea-crossing temporary steel trestle is erected across the sea under the condition of combining the geographical positions of the existing wharf, the first dam and the second dam, the steel trestle main body and the channel type trestle can jointly provide a safe and reliable construction platform for the construction of a bridge to be built, the construction method of the temporary steel trestle is simple and convenient, the construction is convenient, the problem of difficulty in construction of the extra-large-span sea area temporary steel trestle is solved, and the construction period can be shortened.

In order to solve the technical problems, the invention adopts the technical scheme that: a construction method of an n-shaped sea-crossing temporary steel trestle is characterized by comprising the following steps: the temporary steel trestle comprises a steel trestle main body erected on one side of the bridge to be built, the bridge to be built comprises a main bridge to be built and approach bridges to be built arranged on two ends of the main bridge to be built, the main bridge to be built comprises a concrete bridge body erected across the sea and a plurality of concrete piers arranged below the concrete bridge body, the steel trestle main body is erected on one side of the main bridge to be built, two ends of the steel trestle main body are connected with the steel approach bridges erected on one side of the approach bridge to be built, the steel trestle main body comprises a main bridge section and two connecting bridge sections which are respectively arranged on two ends of the main bridge section and are connected with the steel approach bridges, the two connecting bridge sections are positioned on the same side of the main bridge section and are both parallel to the main bridge section, the connecting bridge section is communicated with the main bridge section through transition bridge sections, and the main bridge sections and the two connecting bridge sections jointly form a steel trestle main body in a shape, a plurality of channel type trestle bridges for providing construction channels for the concrete bridge piers are arranged on the main bridge section, the transition bridge section and the connecting bridge section, the extending direction of the channel type trestle bridges is perpendicular to the extending direction of the steel trestle main body, one end of each channel type trestle bridge is a connecting end connected with the steel trestle main body in a shape like a Chinese character 'ji', the other end of each channel type trestle bridge is an overhanging end, and the connecting bridge section is communicated with the existing wharf through the connecting type trestle bridges; the construction method comprises the following steps:

step one, constructing an abutment and a steel approach bridge:

building a bridge abutment on the second dam, erecting a first steel approach bridge right above the first dam, and meanwhile erecting a second steel approach bridge right above the second dam;

step two, construction of two connecting bridge sections:

two connecting bridge sections are respectively for laying at the first connecting bridge section of main bridge section one end and laying at the second connecting bridge section of the main bridge section other end, and the concrete construction step of constructing first connecting bridge section and second connecting bridge section simultaneously includes:

step 201, constructing a first connecting bridge section along the direction that the first connecting bridge section is close to the main bridge section by taking the first steel approach bridge erected in the step one as a construction channel, and constructing a second connecting bridge section along the direction that the second connecting bridge section is close to the main bridge section by taking the second steel approach bridge erected in the step one as a construction channel;

step 202, taking the first connecting bridge section erected in step 201 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the first connecting bridge section; meanwhile, taking the second connecting bridge section erected in the step 201 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the second connecting bridge section;

step 203, taking the second connecting bridge section erected in the step 201 and the existing wharf as a construction channel, and constructing the connecting trestle in opposite directions until the connecting trestle is communicated;

step three, construction of two transition bridge sections:

two bridge sections are respectively for connecting the first bridge section of transition between first bridge section and the main bridge section and connecting the second bridge section of transition between second bridge section and the main bridge section, and the concrete construction step of constructing first bridge section of transition and second bridge section simultaneously includes:

step 301, constructing a first transition bridge section along a direction in which the first transition bridge section is close to the main bridge section by taking the first connecting bridge section erected in the step 201 as a construction channel; constructing a second transition bridge section along the direction in which the second transition bridge section approaches to the main bridge section by taking the erected second connection bridge section in the step 201 as a construction channel;

step 302, taking the first transition bridge section erected in the step 301 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the first transition bridge section; meanwhile, the second transition bridge section erected in the step 301 is used as a construction channel, and construction of a plurality of channel type trestle bridges connected to the second transition bridge section is simultaneously carried out;

step four, constructing the main bridge section, which comprises the following steps:

step 401, constructing the main bridge section in opposite directions until the main bridge section is communicated by taking the first transition bridge section and the second transition bridge section which are erected in the step 301 as construction channels;

and step 402, taking the main bridge section erected in the step 401 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the main bridge section.

The construction method of the n-shaped sea-crossing temporary steel trestle is characterized by comprising the following steps of: the utility model discloses a bridge structure, including concrete pier, linear type combination pier or nonlinear line combination pier, linear type combination pier is main pier, linear type combination pier or nonlinear line combination pier, linear type combination pier is by at least two waiting to build that the straight line was arranged and assists the pier to constitute, nonlinear line combination pier is by two waiting to build the support mound and constitute, the landing stage is supported for enclosing the annular of establishing in main pier week side, is laid to the passageway type a landing stage or is laid a landing stage is supported to a font of linear type combination pier homonymy or is laid an L shape of nonlinear line combination pier homonymy.

The construction method of the n-shaped sea-crossing temporary steel trestle is characterized by comprising the following steps of: in the first step, the first steel approach bridge and the second steel approach bridge are uniformly constructed into multi-span approach bridge sections, the construction processes of the multi-span approach bridge sections are the same, and the construction process of any one span approach bridge section is as follows: firstly, constructing a steel pipe pile foundation of the approach section, and then paving an approach bridge body of the approach section on the constructed steel pipe pile foundation of the approach section; the approach bridge body comprises a transverse steel girder, a longitudinal steel girder erected on the transverse steel girder and an approach bridge panel erected on the longitudinal steel girder.

The construction method of the n-shaped sea-crossing temporary steel trestle is characterized by comprising the following steps of: in step 201, the first connecting bridge section and the second connecting bridge section are equally divided into multiple-span connecting bridge section sections to be sequentially constructed, the construction processes of the multiple-span connecting bridge section sections are the same, and the construction process of any one span connecting bridge section is as follows: and firstly, constructing the steel pipe pile foundation of the connecting bridge section, and then paving the bridge body of the connecting bridge section on the constructed steel pipe pile foundation of the connecting bridge section.

The construction method of the n-shaped sea-crossing temporary steel trestle is characterized by comprising the following steps of: in step 202, step 302 and step 402, the channel-type trestle is divided into multiple-span channel-type trestle sections to be sequentially constructed, the construction processes of the multiple-span channel-type trestle sections are the same, and the construction process of any one span channel-type trestle section is as follows: the construction of the steel pipe pile foundation of the channel type trestle section is firstly carried out, and then the channel type trestle body of the channel type trestle section is laid on the steel pipe pile foundation of the constructed channel type trestle section.

The construction method of the n-shaped sea-crossing temporary steel trestle is characterized by comprising the following steps of: in the first step, after the bridge abutment is built, a section steel distribution beam is arranged on the bridge abutment, and one end of a transverse section steel beam of the second steel approach bridge is fixedly arranged on the section steel distribution beam.

The construction method of the N-shaped sea-crossing temporary steel trestle is characterized in that in the step 201 and the step 401, the main bridge section, the first connecting bridge section and the second connecting bridge section are all non-widened bridge sections, a bridge body of each non-widened bridge section comprises a non-widened steel girder and a non-widened bridge deck positioned right above the non-widened steel girder, N Bailey girders are erected between the non-widened steel girder and the non-widened bridge deck, and N are positive integers.

In step 301, the first transition bridge section and the second transition bridge section both include a non-widened bridge section and two widened bridge sections arranged at two ends of the non-widened bridge section in a staggered manner, the two widened bridge sections of the first transition bridge section are respectively connected with the first connecting bridge section and the main bridge section, and the two widened bridge sections of the second transition bridge section are respectively connected with the second connecting bridge section and the main bridge section; the bridge body of the widened bridge section comprises a widened section steel main beam and a widened bridge deck positioned right above the widened section steel main beam, wherein M Bailey beams are erected between the widened section steel main beam and the widened bridge deck, M is a positive integer, and M is larger than N; and the non-widened steel girder and the widened steel girder are both provided with door-shaped limiting frames for limiting the installation position of the Bailey beam.

The temporary steel trestle of sea is striden to a style of calligraphy of foretell, its characterized in that: the below of the axle body of steel trestle main part is laid a plurality of double steel-pipe pile supports that the interval was laid and a plurality of is laid adjacent two single steel-pipe pile supports between the double steel-pipe pile supports, the below of the axle body of passageway type trestle with the below equipartition of the axle body of connection type trestle is equipped with a plurality of single steel-pipe pile supports, double steel-pipe pile supports including four at least and being two rows of steel-pipe piles of laying, single steel-pipe pile supports including two at least and being the steel-pipe pile that single row was laid, connects through the bridging between two adjacent steel-pipe piles.

Foretell interim steel trestle major structure of sea is striden to several font, its characterized in that: be provided with second dykes and dams gate opening basis on the second dykes and dams, be provided with supplementary steel-pipe pile on the second dykes and dams gate opening basis and support, supplementary steel-pipe pile supports including installing assisting on second dykes and dams gate opening basis with the steel-pipe pile, erect assisting with the top of steel-pipe pile and with assisting with horizontal shaped steel girder steel looks parallel and level add horizontal shaped steel girder steel, the bottom of assisting with the steel-pipe pile is provided with concrete steel pile casing, assist with steel-pipe pile and adjacent connect through the bridging between the steel-pipe pile.

Compared with the prior art, the invention has the following advantages:

1. the steel trestle main body of the temporary steel trestle comprises a main bridge section and two connecting bridge sections which are respectively arranged at two ends of the main bridge section and are used for being connected with a steel approach bridge, wherein the two connecting bridge sections are positioned at the same side of the main bridge section and are parallel to the main bridge section, the connecting bridge sections are communicated with the main bridge section through the transition bridge sections, the main bridge section, the two transition bridge sections and the two connecting bridge sections jointly form a n-shaped steel trestle main body, the connecting bridge sections can enable the extending direction of the steel trestle main body to avoid a cofferdam structure, the integrity of the steel trestle main body can be ensured, the temporary steel trestle provides a stable and reliable construction platform for the construction of a bridge to be built, and when the temporary steel trestle is removed after the construction of the bridge to be built, the construction of the bridge to be built can not be adversely affected.

2. According to the temporary steel trestle, the steel access bridge is erected on one side of the access bridge to be built, the two steel access bridges are respectively connected to the two ends of the steel trestle main body, the two steel access bridges are respectively used as fixing structures for the two ends of the steel trestle main body, the stability of connection between the two ends of the steel trestle main body and the first dam and the second dam can be improved, the steel access bridge can provide a safe and reliable construction platform for erection of a bridge body of the access bridge to be built, and transportation of construction materials and tooling equipment is facilitated.

3. The temporary steel trestle is characterized in that a plurality of channel type trestles are arranged on the main bridge section, the transition bridge section and the connecting bridge section, the extending direction of the channel type trestle is perpendicular to the extending direction of the steel trestle main body, one end of the channel type trestle is a connecting end connected with the steel trestle main body in a shape like a Chinese character 'ji', the other end of the channel type trestle is an overhanging end, namely one end of the channel type trestle is communicated with the steel trestle main body, the other end of the channel type trestle is in a free state, the number of the channel type trestles is equal to the number of concrete piers, and the channel type trestles and the steel trestle main body and the channel type trestles correspond to each other one by one, and the steel trestle main body and the channel type trestles can provide a safe and reliable construction platform for the construction of a bridge to be constructed together, and the steel trestle main body and.

4. The temporary steel trestle of the invention is characterized in that a connecting type trestle is erected between the connecting bridge section and the existing wharf, one end of the connecting type trestle is connected with the second connecting bridge section, the other end of the connecting type trestle is connected with the existing wharf, and the existing wharf and the bridge to be built are respectively positioned at two sides of the connecting bridge section, so that after the connecting type trestle is used for communicating the connecting bridge section with the existing wharf, the connecting type trestle not only serves as a construction channel, more importantly, the connecting type trestle and the existing wharf form a fixed structure positioned at one side of the connecting bridge section together, and the stability of the connecting bridge section and the steel trestle main body can be improved.

5. The construction method of the temporary steel trestle is simple, can shorten the construction period and is convenient to popularize and apply.

In summary, the invention can erect the temporary steel trestle in the shape of a Chinese character 'ji' across the sea under the condition of combining the geographical positions of the existing wharf, the first dam and the second dam, and the steel trestle main body and the channel type trestle can provide a safe and reliable construction platform for the construction of the bridge to be built.

The invention is described in further detail below with reference to the figures and examples.

Drawings

FIG. 1 is a flow chart of the construction method of the present invention.

FIG. 2 is a schematic view of the connection relationship among the steel trestle main body, the steel approach bridge, the concrete pier and the existing wharf.

FIG. 3 is a schematic view showing the connection relationship between the steel trestle body, the steel approach bridge, the first dam and the second dam according to the present invention.

FIG. 4 is a schematic structural view of a non-widened bridge segment according to the present invention.

Fig. 5 is a schematic structural view of a widened bridge section according to the invention.

FIG. 6 is a schematic view of a connection structure of an approach bridge body and a single-row steel pipe pile support.

FIG. 7 is a schematic view showing the connection relationship between the second steel approach bridge, the auxiliary steel pipe pile supports, the second dam gate foundation and the second dam gate sidewall according to the present invention.

Description of reference numerals:

1-main bridge section; 1-2-a first connecting bridge section; 1-3-a second connecting bridge section;

1-4-a first transition bridge section; 1-5-a second transition bridge section;

2-a first steel approach bridge; 3-second steel approach bridge; 4-abutment;

5-existing wharfs; 6-annular trestle; 7-a straight trestle;

8-connecting type trestle bridges; 9-1-a first straight line channel type trestle;

9-2-a second straight-line section channel type trestle; 10 — a first dam;

11-a second dam; 12-main bridge pier to be built; 13-auxiliary bridge piers to be built;

14, building a support pier; 15-section steel distribution beam; 18-second dam gate foundation;

19-second dam gate sidewall; 20-1 — a non-widened section steel main beam;

20-2 — non-widening deck slab; 20-3-beret beam; 20-4-door type spacing rack;

21-1-steel pipe pile; 21-2-a cross brace; 22-1-transverse section steel beam;

22-2-longitudinal steel section and beam; 22-2-access panel; 23-1-adding a transverse steel girder;

23-2-adding a steel pipe pile; 23-3-concrete steel casing; 24-1-widening the steel girder;

24-2-widening the deck slab.

Detailed Description

As shown in fig. 1, 2 and 3, the temporary steel trestle of the invention comprises a steel trestle main body erected on one side of the bridge to be built, the bridge to be built comprises a main span bridge to be built and approach bridges to be built arranged on two ends of the main span bridge to be built, the main span bridge to be built comprises a concrete bridge body erected across the sea and a plurality of concrete piers arranged below the concrete bridge body, the steel trestle main body is erected on one side of the main span bridge to be built, two ends of the steel trestle main body are connected with the steel approach bridge erected on one side of the approach bridge to be built, the steel trestle main body comprises a main bridge section 1-1 and two connecting bridge sections respectively arranged on two ends of the main bridge section 1-1 and used for being connected with the steel approach bridge, the two connecting bridge sections are positioned on the same side of the main bridge section 1-1 and are both parallel to the main bridge section 1-1, the main bridge section 1-1, the two transition bridge sections and the two connecting bridge sections form a U-shaped steel trestle main body together, a plurality of channel type trestles for providing construction channels for the concrete piers are arranged on the main bridge section 1-1, the transition bridge sections and the connecting bridge sections, the extending direction of the channel type trestles is perpendicular to the extending direction of the steel trestle main body, one end of each channel type trestle is a connecting end connected with the U-shaped steel trestle main body, the other end of each channel type trestle is an overhanging end, and the connecting bridge sections are communicated with the existing wharfs 5 through connecting type trestles 8; the construction method comprises the following steps:

step one, constructing an abutment and a steel approach bridge:

building a bridge abutment 4 on a second dam 11, erecting a first steel approach bridge 2 right above the first dam 10, and simultaneously erecting a second steel approach bridge 3 right above the second dam 11;

in this embodiment, since the bridge to be built includes a main bridge to be built including a concrete bridge body and a concrete bridge pier erected across the sea, a first access bridge to be built, and a second access bridge to be built, since the total length of the first access bridge is 720m and the total length of the second access bridge is 600m, for the second access bridge to be built and the first access bridge having the total length exceeding 500m, in actual construction, when the concrete bridge body and the concrete bridge pier of the main bridge to be built are constructed, by erecting a temporary steel trestle at one side of the bridge to be built, the extending direction of the temporary steel trestle coincides with the extending direction of the bridge to be built, since the bridge to be built is not a straight bridge, the middle portion of the bridge to be built is deviated to the north side, and at the same time, when the bridge pier of the first access bridge and the pier of the second access bridge to be built are constructed, it is necessary to construct a first cofferdam structure near the first dam 10, the second cofferdam structure is built near the second dam 11 to avoid the erection of the steel trestle main body from being affected by the first cofferdam structure and the second cofferdam structure, so in the present embodiment, the construction of the abutment 4, the first steel access bridge 2 and the second steel access bridge 3 is performed in the first step, because: when a steel trestle main body is constructed subsequently, the first steel access bridge 2 and the second steel access bridge 3 not only need to be respectively used as fixing structures at two ends of the steel trestle main body to ensure the stability of connection between two ends of the steel trestle main body and the first dam 10 and the second dam 11, but also more importantly, the first steel access bridge 2 needs to be used as a bridge body of a second access bridge to be built to provide a safe and reliable construction platform, and the second steel access bridge 3 needs to be used as a bridge body of a first access bridge to be built to provide a safe and reliable construction platform and a construction channel, so that the bridge abutment 4, the first steel access bridge 2 and the second steel access bridge 3 need to be constructed in step one.

As shown in fig. 3, in actual use, the deck elevation of the first steel access bridge 2 and the deck elevation of the second steel access bridge 3 are determined according to factors such as the dam crest elevation of the first dam 10, the dam crest elevation of the second dam 11, the crest elevation of the existing wharf 5, the annual highest tide level of the construction sea area, and the like, in this embodiment, since the dam crest elevation of the first dam 10 is 4.2m, the crest elevation of the existing wharf 5 is 4.4m, the dam crest elevation of the second dam 11 is 6.16m, and the annual highest tide level of the construction sea area is 3.3m, in order to ensure that the deck elevation of the first steel access bridge 2 and the deck main body are normally connected and the deck elevation of the second steel access bridge 3 and the deck main body are normally connected, the deck elevation of the deck main body is 5.8m, the deck elevation of the first steel access bridge 2 and the deck main body are connected is 5.8m, the elevation of the other end of the first steel access bridge 2 and the deck main body is 5.4m, the bridge deck elevation of one end of the second steel approach bridge 3 connected with the abutment 4 is 6.16 m.

Step two, construction of two connecting bridge sections:

the two connecting bridge sections are respectively a first connecting bridge section 1-2 arranged at one end of the main bridge section 1-1 and a second connecting bridge section 1-3 arranged at the other end of the main bridge section 1-1, and the concrete construction steps of simultaneously constructing the first connecting bridge section 1-2 and the second connecting bridge section 1-3 comprise:

step 201, constructing a first connecting bridge section 1-2 along the direction that the first connecting bridge section 1-2 is close to the main bridge section 1-1 by taking the first steel approach bridge 2 erected in the step one as a construction channel, and constructing a second connecting bridge section 1-3 along the direction that the second connecting bridge section 1-3 is close to the main bridge section 1-1 by taking the second steel approach bridge 3 erected in the step one as a construction channel;

as shown in fig. 2 and 3, in this embodiment, the steel trestle main body comprises a main bridge section 1-1, a first connecting bridge section 1-2 and a second connecting bridge section 1-3, the first connecting bridge section 1-2 can make the extending direction of the steel trestle main body avoid the first cofferdam structure, the second connecting bridge section 1-3 can make the extending direction of the steel trestle main body avoid the second cofferdam structure, therefore, when the construction of the steel trestle main body is completed under the premise that the construction of the first steel bridge 2 and the second steel bridge 3 is completed, the first construction must be the first connecting bridge section 1-2 and the second connecting bridge section 1-3, because the construction space of the first connecting bridge section 1-2 is opposite to the construction space of the second connecting bridge section 1-3, and is not interfered with each other, when the first connecting bridge section 1-2 and the second connecting bridge section 1-3 are constructed synchronously, the construction period can be greatly shortened.

Step 202, taking the first connecting bridge section 1-2 erected in the step 201 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the first connecting bridge section 1-2; meanwhile, taking the second connecting bridge sections 1-3 erected in the step 201 as construction channels, and simultaneously constructing a plurality of channel type trestle bridges connected to the second connecting bridge sections 1-3;

in this embodiment, a plurality of channel-type trestles located on one side of the concrete pier are arranged on the main bridge section 1-1, the first connecting bridge section 1-2, the second connecting bridge section 1-3, the first transition bridge section 1-4 and the second transition bridge section 1-5, the number of the channel-type trestles is equal to that of the concrete piers, the channel-type trestles correspond to the concrete piers one by one, one end of each channel-type trestle is communicated with the steel trestle main body, the other end of each channel-type trestle is in a free state, the steel trestle main body and the channel-type trestles can provide a safe and reliable construction platform for construction of a bridge to be built, and the steel trestle main body and the channel-type trestles have the advantages of being convenient to construct and convenient to disassemble.

In this embodiment, after the first connecting bridge section 1-2 and the second connecting bridge section 1-3 are both constructed, a plurality of channel-type trestles can be performed, the first connecting bridge section 1-2 is used as a construction reference and a construction channel, and a plurality of channel-type trestles connected to the first connecting bridge section 1-2 are simultaneously constructed, so that construction management is facilitated, meanwhile, the function of checking the construction accuracy of the first connecting bridge section 1-2 can be performed, the second connecting bridge section 1-3 is used as a construction reference and a construction channel, the function of checking the construction accuracy of the second connecting bridge section 1-3 can be simultaneously performed, and meanwhile, the function of checking the construction accuracy of the second connecting bridge section 1-3 can be performed.

Step 203, constructing the connecting trestle 8 in opposite directions until the second connecting bridge section 1-3 erected in the step 201 and the existing wharf 5 are used as construction channels until the connecting trestle is communicated;

as shown in fig. 2, in this embodiment, by erecting a connecting trestle 8 between the second connecting trestle section 1-3 and the existing quay 5, in practical use, the connecting trestle 8 comprises a widened trestle section connected with the second connecting trestle section 1-3 and a plurality of non-widened trestle sections connected with the widened trestle section, the width of the bridge body of the non-widened trestle section is 6m, the width of the bridge body of the widened trestle section ranges from 8m to 10m, one end of the connecting trestle 8 is connected with the second connecting trestle section 1-3, the other end of the connecting trestle 8 is connected with the existing quay 5, and since the existing quay 5 and the bridge to be built are respectively located at both sides of the second connecting trestle section 1-3, at this time, the connecting trestle 8 not only serves as a construction passage after the second connecting trestle section 1-3 is connected with the existing quay 5 by the connecting trestle 8, more importantly, the connecting type trestle 8 and the existing wharf 5 jointly form a fixed structure positioned at one side of the second connecting bridge section 1-3, the stability of the second connecting bridge section 1-3 and the steel trestle body can be improved, it needs to be noted that the construction precision requirement of the connecting type trestle 8 is lower than that of the second connecting bridge section 1-3 and a plurality of channel type trestles connected to the second connecting bridge section 1-3, therefore, on the premise that the construction of the second connecting bridge section 1-3 is completed, in order to ensure the construction accuracy of the second connecting bridge section 1-3 and the plurality of channel type trestles connected to the second connecting bridge section 1-3, the construction of the connecting type trestle 8 must be performed after the construction of the second connecting bridge section 1-3 and the plurality of channel type trestles connected to the second connecting bridge section 1-3 is completed.

Step three, construction of two transition bridge sections:

the two transition bridge sections are respectively a first transition bridge section 1-4 connected between a first connecting bridge section 1-2 and a main bridge section 1-1 and a second transition bridge section 1-5 connected between a second connecting bridge section 1-3 and the main bridge section 1-1, and the concrete construction steps of simultaneously constructing the first transition bridge section 1-4 and the second transition bridge section 1-5 comprise:

step 301, constructing a first transition bridge section 1-4 along a direction that the first transition bridge section 1-4 is close to the main bridge section 1-1 by taking the first connecting bridge section 1-2 erected in the step 201 as a construction channel; constructing a second transition bridge section 1-5 along the direction that the second transition bridge section 1-5 is close to the main bridge section 1-1 by taking the erected second connecting bridge section 1-3 in the step 201 as a construction channel;

as shown in fig. 2 and 3, in this embodiment, the first connecting bridge section 1-2 is connected to the main bridge section 1-1 through a first transition bridge section 1-4, the second connecting bridge section 1-3 is connected to the main bridge section 1-1 through a second transition bridge section 1-5, the first connecting bridge section 1-2 and the second connecting bridge section 1-3 are both parallel to the main bridge section 1-1, the main bridge section 1-1 is located on the north side of the first connecting bridge section 1-2 and the second connecting bridge section 1-3, at this time, the steel trestle body is in a zigzag shape, the purpose of adjusting the extending direction of the temporary steel trestle can be achieved through the first transition bridge section 1-4 and the second transition bridge section 1-5, meanwhile, the integrity of the steel trestle body can be ensured, and the temporary steel trestle provides a stable construction platform for the construction of the bridge to be constructed, after the construction of the bridge to be built is finished, when the temporary steel trestle is dismantled, the constructed bridge to be built cannot be adversely affected, so that the construction of the first transition bridge section 1-4 and the second transition bridge section 1-5 can be carried out on the premise that the construction of the first connecting bridge section 1-2 and the second connecting bridge section 1-3 is finished, and the construction of the first transition bridge section 1-4 and the second transition bridge section 1-5 must be used as a precondition for the construction of the main bridge section 1-1.

Step 302, taking the first transition bridge sections 1-4 erected in the step 301 as construction channels, and simultaneously constructing a plurality of channel type trestle bridges connected to the first transition bridge sections 1-4; meanwhile, taking the second transition bridge section 1-5 erected in the step 301 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the second transition bridge section 1-5;

step 401, constructing the main bridge section 1-1 in opposite directions until the main bridge section 1-1 is communicated by taking the first transition bridge section 1-4 and the second transition bridge section 1-5 which are erected in the step 301 as construction channels;

and step 402, taking the main bridge section 1-1 erected in the step 401 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the main bridge section 1-1.

In this embodiment, when the main bridge section 1-1 is oppositely constructed in step 401, since the main bridge section 1-1 is located at the center of the sea area, the construction environment is severe, so that it is important to improve the construction efficiency and shorten the construction period, and after the construction of both the two connecting bridge sections and the two transition bridge sections is completed, the main bridge section 1-1 is oppositely constructed, so that a convenient and safe construction condition can be provided for the main bridge section 1-1.

As shown in fig. 2, in this embodiment, the concrete pier is main pier 12, linear type combination pier or nonlinear type combination pier, linear type combination pier is by at least two wait to build that the straight line was arranged and assists pier 13 to constitute, nonlinear type combination pier comprises two waiting to build support piers 14 that the dislocation was laid, the landing stage is supported for enclosing annular 6, the establishment of establishing in main pier 12 week side of the bridge, and the linear 7 or the establishment of the landing stage of linear type combination pier homonymy are supported the landing stage of L shape of nonlinear type combination pier homonymy.

During actual construction, according to the structure of concrete bridge pier, confirm the structure of trestle is propped up to the passageway type, when concrete bridge pier is main pier 12, trestle 6 is propped up for enclosing the annular of establishing in main pier 12 week side to trestle 6 is propped up to the passageway type, and the quantity of trestle 6 is propped up to the annular equals the quantity of main pier 12, and its reason lies in: the cross section of the main pier 12 is rectangular, the main pier 12 is arranged below the bridge body of the main bridge section 1-1, the main pier 12 mainly plays a role in bearing the weight of the bridge body of the main bridge section 1-1, the main pier 12 has the characteristics of large volume and large bearing capacity, a single-sided construction platform cannot meet the construction requirements of the main pier 12, therefore, the annular trestle 6 is communicated with the main bridge section 1-1 and is arranged around the main bridge pier 12, the main bridge section 1-1 and the annular trestle 6 jointly form an annular construction platform communicated with each other on four side surfaces of the main bridge pier 12, the construction requirement of the main bridge pier 12 can be met, at the moment, the main bridge section 1-1 and the annular trestle 6 can provide a safe and stable construction platform for the construction of the main pier 12, can achieve the purpose of transporting materials and tooling equipment required by the main pier 12, and can achieve the purpose of casting the main pier 12 on site.

During actual construction, the body width of the annular trestle 6 is 8m, the distance between the side of the main pier 12 and the inner side of the bridge deck of the annular trestle 6 is 4.5m, the annular trestle 6 and the steel trestle main body are communicated into a whole, the crawler crane can conveniently walk on the bridge deck of the annular trestle 6, and meanwhile, the construction requirement of the steel cofferdam locking steel pipe pile of the main pier 12 can be met.

In this embodiment, when the concrete pier is linear type combination pier, linear type combination pier is by at least two wait to build that it constructs and assists 13 formation to be arranged linearly, and at this moment, trestle 7, its aim at are propped up for laying the in-line trestle of linear type combination pier homonymy to the passageway type: because a plurality of linear type combined piers are arranged at intervals below the bridge body of the first connecting bridge section 1-2, the bridge body of the second connecting bridge section 1-3, the bridge body of the first transition bridge section 1-4 and the bridge body of the second transition bridge section 1-5, the cross section of the auxiliary pier 13 to be built is also rectangular, but the cross section area of the auxiliary pier 13 to be built is less than 5 square meters, a single-side construction platform provided by the linear type trestle 7 can construct the main pier 12, the number of the linear type trestles 7 is equal to that of the linear type combined piers, and the extension length of the linear type trestle 7 is determined according to the width of the combined piers.

In this embodiment, the length of the in-line trestle 7 ranges from 3m to 5m, and the width of the bridge body of the in-line trestle 7 is 6 m.

In this embodiment, when the concrete pier is nonlinear line type combination pier, nonlinear line type combination pier is by two dislocation laying wait to build support pier 14 and form, consequently, the trestle is supported for laying two L shape of waiting to build support pier 14 homonymies to the channel type, and nonlinear line type combination pier is located the below of the hookup location department of second connecting bridge section 1-3 and second steel approach 3, and its reason lies in: the cross section of the support pier 14 to be built is also rectangular, and the cross section area of the support pier 14 to be built is also less than 5 square meters, however, because the in-line trestle 7 can not meet the construction requirement of constructing two support piers 14 to be built at the same time due to the special arrangement positions of the two support piers 14 to be built, an L-shaped trestle capable of providing a safe and reliable construction platform for constructing the two support piers 14 to be built at the same time needs to be arranged, the L-shaped trestle comprises a first straight-line channel-type trestle 9-1 and a second straight-line channel-type trestle 9-2 connected with one end of the first straight-line channel-type trestle 9-1, the first straight-line channel-type trestle 9-1 is connected with the second connecting bridge section 1-3 and is positioned at one side of one support pier 14 to be built, the second straight-line channel-type trestle 9-2 is positioned at one side of the other support pier 14 to, and because two support piers 14 to be built are close to the second dam 11, the construction space of the two support piers 14 to be built is limited, so that only when the L-shaped support trestle is located at the same side of the two support piers 14 to be built, the L-shaped support trestle can have enough erection space, and the construction of the two support piers 14 to be built can be met.

As shown in fig. 6, in the first embodiment, in the step one, the first steel approach bridge 2 and the second steel approach bridge 3 are both divided into multiple approach bridge sections to be sequentially constructed, the construction process of the multiple approach bridge sections is the same, and the construction process of any one of the multiple approach bridge sections is as follows: firstly, constructing a steel pipe pile foundation of the approach section, and then paving an approach bridge body of the approach section on the constructed steel pipe pile foundation of the approach section; the bridge approach body comprises a transverse steel section girder 22-1, a longitudinal steel section girder 22-2 erected on the transverse steel section girder 22-1 and a bridge approach panel 22-3 erected on the longitudinal steel section girder 22-2.

In this embodiment, in step 201, the first connecting bridge section 1-2 and the second connecting bridge section 1-3 are both divided into multiple connecting bridge section segments, which are sequentially constructed, the construction processes of the multiple connecting bridge section segments are the same, and the construction process of any one connecting bridge section segment is as follows: and firstly, constructing the steel pipe pile foundation of the connecting bridge section, and then paving the bridge body of the connecting bridge section on the constructed steel pipe pile foundation of the connecting bridge section.

In this embodiment, in step 202, step 302, and step 402, the construction methods of the channel-type trestle connected to the main bridge section 1-1, the first connecting bridge section 1-2, the second connecting bridge section 1-3, the first transition bridge section 1-4, or the second transition bridge section 1-5 are all the same, the channel-type trestle is divided into multiple channel-type trestle sections to be constructed sequentially, the construction processes of the multiple channel-type trestle sections are all the same, and the construction process of any one channel-type trestle section is: the construction of the steel pipe pile foundation of the channel type trestle section is firstly carried out, and then the channel type trestle body of the channel type trestle section is laid on the steel pipe pile foundation of the constructed channel type trestle section.

As shown in fig. 3, in the first step, after the bridge abutment 4 is constructed, the section steel distribution beam 15 is laid on the bridge abutment 4, and one end of the transverse section steel beam 22-1 of the second steel approach bridge 3 is fixedly mounted on the section steel distribution beam 15.

In this embodiment, the structural steel distribution beam 15 is disposed on the abutment 4, and when the bridge body of the second steel approach bridge 3 is laid, the reason for this is that: if one end of the transverse steel girder 22-1 is directly connected to the abutment 4, the transverse steel girder 22-1 of the second steel access bridge 3 can continuously bear a large transverse force in the long-term use process, and the abutment 4 is easily crushed, and if one end of the transverse steel girder 22-1 of the second steel access bridge 3 is fixedly arranged on the section steel distribution beam 15, the transverse force borne by the transverse steel girder 22-1 of the second steel access bridge 3 can be uniformly distributed on the abutment 4 by using the section steel distribution beam 15, so that the abutment 4 can be prevented from being damaged, and the connection between the transverse steel girder 22-1 and the section steel distribution beam 15 is convenient for construction and disassembly and has a good use effect.

As shown in fig. 2 and 4, in step 201 and step 401, in the present embodiment, the main bridge section 1-1, the first connecting bridge section 1-2, and the second connecting bridge section 1-3 are all non-widened bridge sections, a bridge body of the non-widened bridge sections includes a non-widened steel girder 20-1 and a non-widened bridge deck 20-2 located directly above the non-widened steel girder 20-1, and N beret beams 20-3 are erected between the non-widened steel girder 20-1 and the non-widened bridge deck 20-2, where N is a positive integer.

As shown in fig. 2 and 5, in step 301, in this embodiment, each of the first transition bridge section 1-4 and the second transition bridge section 1-5 includes a non-widened bridge section and two widened bridge sections arranged at two ends of the non-widened bridge section in a staggered manner, two widened bridge sections of the first transition bridge section 1-4 are respectively connected with the first connecting bridge section 1-2 and the main bridge section 1-1, and two widened bridge sections of the second transition bridge section 1-5 are respectively connected with the second connecting bridge section 1-3 and the main bridge section 1-1; the bridge body of the widened bridge section comprises a widened section steel main beam 24-1 and a widened bridge deck 24-2 located right above the widened section steel main beam 24-1, wherein M Bailey beams 20-3 are erected between the widened section steel main beam 24-1 and the widened bridge deck 24-2, M is a positive integer and M is larger than N; the non-widened steel main beam 20-1 and the widened steel main beam 24-1 are both provided with door-shaped limiting frames 20-4 used for limiting the installation position of the Bailey beam 20-3.

In actual assembly, because the first connecting bridge section 1-2 is parallel to the main bridge section 1-1, in two widened bridge sections of the first transition bridge section 1-4, the south side of the widened bridge section connected with the first connecting bridge section 1-2 is flush with the south side of the first connecting bridge section 1-2, and the north side of the widened bridge section connected with the main bridge section 1-1 is flush with the north side of the main bridge section 1-1, at this time, the two widened bridge sections are not arranged in a straight line, but arranged in a staggered manner, so that the first transition bridge section 1-4 can realize the purpose of connecting the first connecting bridge section 1-2 with the main bridge section 1-1; because the second connecting bridge section 1-3 is parallel to the main bridge section 1-1, in the two widened bridge sections of the second transition bridge section 1-5, the north side of the widened bridge section connected with the main bridge section 1-1 is flush with the north side of the main bridge section 1-1, and the south side of the widened bridge section connected with the second connecting bridge section 1-3 is flush with the south side of the second connecting bridge section 1-3, at this time, the two widened bridge sections are not arranged in a straight line, but arranged in a staggered way, so that the second transition bridge section 1-5 can realize the purpose of connecting the main bridge section 1-1 with the second connecting bridge section 1-3; the south side of the widened bridge section, the south side of the first connecting bridge section 1-2 and the south side of the second connecting bridge section 1-3 are all sides of the steel trestle main body connected with the linear trestle 7, and the north side of the widened bridge section and the north side of the main bridge section 1-1 are all sides of the steel trestle main body not connected with the linear trestle 7.

In this embodiment, when the width of the bridge body of the non-widened bridge section is 8m, the value range of the width of the bridge body of the widened bridge section is 10m to 12m, and the number of the bailey beams 20-3 is 6.

During actual use, determining the structural parameters of the temporary steel trestle according to factors such as the speed of the temporary steel trestle on the vehicle, the load which can be borne by the temporary steel trestle, the service life of the temporary steel trestle and the like, wherein in the embodiment, the speed of the temporary steel trestle on the vehicle is 10 km/h; the value range of the load size that interim steel trestle can bear is: 40t to 100 t; the service life of the temporary steel trestle ranges from 2 years to 2.5 years, so that when the width of the bridge body of the non-widened bridge section is 8m, the number of the Bailey beams 20-3 is 4, and the 4 Bailey beams 20-3 are arranged at equal intervals along the width direction of the bridge body of the non-widened bridge section.

In this embodiment, after the bridge body of every steel trestle main part of striding is laid, still need in time carry on every installation of striding the bridge body both sides safety protection railing of steel trestle main part, it needs to explain that has a construction passageway that link up in order to guarantee that steel trestle main part and the crossing position department of passageway type trestle, consequently, main trestle and the crossing position department of passageway type trestle need not install safety protection railing.

As shown in fig. 3 to 7, in this embodiment, a plurality of double-row steel pipe pile supports arranged at intervals and a plurality of single-row steel pipe pile supports arranged between two adjacent double-row steel pipe pile supports are arranged below a bridge body of a steel trestle main body, a plurality of single-row steel pipe pile supports are uniformly arranged below the bridge body of the channel type trestle and below the bridge body of the connection type trestle 8, the double-row steel pipe pile supports include at least four steel pipe piles 21-1 arranged in two rows, the single-row steel pipe pile supports include at least two steel pipe piles 21-1 arranged in a single row, and the two adjacent steel pipe piles 21-1 are connected through shear braces 21-2.

In the embodiment, because the volume of the double-row steel pipe pile support is larger than that of the single-row steel pipe pile support, the shearing resistance of the double-row steel pipe pile support is superior to that of the single-row steel pipe pile support, the bearing capacity of the double-row steel pipe pile support is larger than that of the single-row steel pipe pile support, therefore, the bridge body of the steel trestle main body is supported by a plurality of double-row steel pipe pile supports and a plurality of single-row steel pipe pile supports together, because the width of the bridge body of the channel type trestle and the width of the bridge body of the connecting type trestle 8 are both smaller than the width of the bridge body of the steel trestle main body, the bearing capacity requirement of the bridge body of the channel type trestle and the bearing capacity requirement of the bridge body of the connecting type trestle 8 are far lower than the bearing capacity requirement of the bridge body of the steel trestle main body, therefore, the bridge body of the channel type trestle and the bridge body of the connecting type trestle 8 are supported by a plurality of single-row steel pipe piles, and double-row steel pipe pile supports do not need to be arranged below the bridge body of the channel type trestle and the bridge body of the connecting type trestle 8.

In the embodiment, the number of the double rows of steel pipe pile supports is at least six; when the number of the double-row steel pipe pile supports is six, the six double-row steel pipe pile supports are respectively arranged below the bridge body at the connecting position of the main bridge section 1-1 and the transition bridge section, below the bridge body at the connecting position of the transition bridge section and the connecting bridge section, and below the bridge body at the connecting position of the connecting bridge section and the steel approach bridge.

The number of the steel pipe piles 21-1 supported by the single row of steel pipe piles arranged below the bridge body of the widened bridge section is larger than the number of the steel pipe piles 21-1 supported by the single row of steel pipe piles arranged below the bridge body of the non-widened bridge section, and the number of the steel pipe piles 21-1 and the distance between every two adjacent steel pipe piles 21-1 are adjusted according to the width of the bridge body of the widened bridge section, so that the stability of the support of the single row of steel pipe piles is ensured.

As shown in fig. 7, in the present embodiment, a second dam gate base 18 is provided on the second dam 11, an auxiliary steel pipe pile support is provided on the second dam gate base 18, the auxiliary steel pipe pile support includes an auxiliary steel pipe pile 23-2 installed on the second dam gate base 18, an auxiliary transverse steel beam 23-1 erected on the top of the auxiliary steel pipe pile 23-2 and flush with the transverse steel beam 22-1, a concrete steel casing 23-3 is provided on the bottom of the auxiliary steel pipe pile 23-2, and the auxiliary steel pipe pile 23-2 is connected to the adjacent steel pipe pile 21-1 through a shear brace 21-2.

In actual construction, since the second dam doorway side wall 19 obstructs the construction of the steel pipe pile foundation of the second steel access bridge 3, when the steel pipe pile foundation of the second steel access bridge 3 is constructed, the steel pipe pile 21-1 positioned at the leftmost side is moved to the right side so as to avoid collision with the second dam doorway side wall 19, at the same time, an auxiliary steel pipe pile 23-2 is additionally arranged at the left side of the second dam doorway side wall 19, the bottom end of the auxiliary steel pipe pile 23-2 is driven on the second dam doorway base 18, a concrete steel casing 23-3 is arranged at the bottom of the auxiliary steel pipe pile 23-2 so as to ensure the stability of the auxiliary steel pipe pile 23-2, an auxiliary transverse steel beam 23-1 flush with the transverse steel beam 22-1 is laid at the top of the auxiliary steel pipe pile 23-2, and a shear brace 21-2 is installed between the auxiliary steel pipe pile 23-2 and the adjacent steel pipe pile 21-1, at the moment, the auxiliary steel pipe pile 23-2, the auxiliary transverse steel girder 23-1, the steel pipe pile 21-1 and the transverse steel girder 22-1 are connected into a whole, so that the problem that the second dam gate side wall 19 blocks the construction of the steel pipe pile foundation of the second steel access bridge 3 is solved, and the structure is stable.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A construction method of an n-shaped sea-crossing temporary steel trestle is characterized by comprising the following steps: the temporary steel trestle comprises a steel trestle main body erected on one side of the bridge to be built, the bridge to be built comprises a main bridge to be built and approach bridges to be built arranged at two ends of the main bridge to be built, the main bridge to be built comprises a concrete bridge body erected across the sea and a plurality of concrete piers arranged below the concrete bridge body, the steel trestle main body is erected on one side of the main bridge to be built, two ends of the steel trestle main body are connected with the steel approach bridge erected on one side of the approach bridge to be built, the steel trestle main body comprises a main bridge section (1-1) and two connecting bridge sections which are respectively arranged at two ends of the main bridge section (1-1) and are used for being connected with the steel approach bridge, the two connecting bridge sections are positioned on the same side of the main bridge section (1-1) and are parallel to the main bridge section (1-1), and the connecting bridge sections are communicated with the main bridge section (1-1) through transition bridge sections, the main bridge section (1-1), the two transition bridge sections and the two connecting bridge sections jointly form a U-shaped steel trestle main body, a plurality of channel type trestles for providing construction channels for the concrete bridge piers are arranged on the main bridge section (1-1), the transition bridge sections and the connecting bridge sections, the extending direction of the channel type trestles is perpendicular to the extending direction of the steel trestle main body, one end of each channel type trestle is a connecting end connected with the U-shaped steel trestle main body, the other end of each channel type trestle is an overhanging end, and the connecting bridge sections are communicated with the existing wharfs (5) through connecting type trestles (8); the construction method comprises the following steps:

step one, constructing an abutment and a steel approach bridge:

building a bridge abutment (4) on a second dam (11), erecting a first steel approach bridge (2) right above the first dam (10), and meanwhile erecting a second steel approach bridge (3) right above the second dam (11);

step two, construction of two connecting bridge sections:

the concrete construction steps of simultaneously constructing the first connecting bridge section (1-2) and the second connecting bridge section (1-3) comprise that the two connecting bridge sections are respectively a first connecting bridge section (1-2) arranged at one end of the main bridge section (1-1) and a second connecting bridge section (1-3) arranged at the other end of the main bridge section (1-1):

step 201, constructing a first connecting bridge section (1-2) along a direction that the first connecting bridge section (1-2) is close to the main bridge section (1-1) by taking the first steel approach bridge (2) erected in the step one as a construction channel, and constructing a second connecting bridge section (1-3) along a direction that the second connecting bridge section (1-3) is close to the main bridge section (1-1) by taking the second steel approach bridge (3) erected in the step one as a construction channel;

step 202, taking the first connecting bridge section (1-2) erected in the step 201 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the first connecting bridge section (1-2); meanwhile, the second connecting bridge section (1-3) erected in the step 201 is used as a construction channel, and a plurality of channel type trestle bridges connected to the second connecting bridge section (1-3) are constructed simultaneously;

step 203, constructing the connecting trestle (8) in opposite directions until the second connecting bridge section (1-3) erected in the step 201 and the existing wharf (5) are communicated with each other by taking the erected second connecting bridge section and the existing wharf (5) as construction channels;

step three, construction of two transition bridge sections:

the two transition bridge sections are respectively a first transition bridge section (1-4) connected between the first connecting bridge section (1-2) and the main bridge section (1-1) and a second transition bridge section (1-5) connected between the second connecting bridge section (1-3) and the main bridge section (1-1), and the concrete construction steps of simultaneously constructing the first transition bridge section (1-4) and the second transition bridge section (1-5) comprise:

301, constructing a first transition bridge section (1-4) in the direction in which the first transition bridge section (1-4) is close to the main bridge section (1-1) by taking the first connecting bridge section (1-2) erected in the step 201 as a construction channel; constructing a second transition bridge section (1-5) along the direction that the second transition bridge section (1-5) is close to the main bridge section (1-1) by taking the second connecting bridge section (1-3) which is erected in the step 201 as a construction channel;

step 302, taking the first transition bridge section (1-4) erected in the step 301 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the first transition bridge section (1-4); meanwhile, the second transition bridge section (1-5) erected in the step 301 is used as a construction channel, and a plurality of channel type trestle bridges connected to the second transition bridge section (1-5) are constructed simultaneously;

step 401, constructing the main bridge section (1-1) in opposite directions until the main bridge section is communicated by taking the first transition bridge section (1-4) and the second transition bridge section (1-5) which are erected in the step 301 as construction channels;

and step 402, taking the main bridge section (1-1) erected in the step 401 as a construction channel, and simultaneously constructing a plurality of channel type trestle bridges connected to the main bridge section (1-1).

2. The construction method of the n-shaped sea-crossing temporary steel trestle according to claim 1, characterized in that: concrete pier is main pier (12), linear type combination pier or nonlinear type combination pier, linear type combination pier is by at least two waiting to build that the straight line was arranged and assists pier (13) to form, nonlinear type combination pier is by two dislocation laying waiting to build support pier (14) and constitutes, landing stage (6), the laying are supported for enclosing to establish in the annular of main pier (12) week side to the passageway type landing stage (7) or the laying are supported to a font of linear type combination pier homonymy landing stage (7) or the laying are supported to the L shape of nonlinear type combination pier homonymy.

3. The construction method of the n-shaped sea-crossing temporary steel trestle according to claim 1, characterized in that: in the first step, the first steel approach bridge (2) and the second steel approach bridge (3) are uniformly constructed into multiple-span approach bridge sections in sequence, the construction processes of the multiple-span approach bridge sections are the same, and the construction process of any one span approach bridge section is as follows: firstly, constructing a steel pipe pile foundation of the approach section, and then paving an approach bridge body of the approach section on the constructed steel pipe pile foundation of the approach section; the bridge approach body comprises a transverse steel girder (22-1), a longitudinal steel girder (22-2) erected on the transverse steel girder (22-1) and a bridge approach panel (22-3) erected on the longitudinal steel girder (22-2).

4. The construction method of the n-shaped sea-crossing temporary steel trestle according to claim 1, characterized in that: in step 201, the first connecting bridge section (1-2) and the second connecting bridge section (1-3) are divided into multiple connecting bridge section sections for sequential construction, the construction processes of the multiple connecting bridge section sections are the same, and the construction process of any connecting bridge section is as follows: and firstly, constructing the steel pipe pile foundation of the connecting bridge section, and then paving the bridge body of the connecting bridge section on the constructed steel pipe pile foundation of the connecting bridge section.

5. The construction method of the n-shaped sea-crossing temporary steel trestle according to claim 1, characterized in that: in step 202, step 302 and step 402, the channel-type trestle is divided into multiple-span channel-type trestle sections to be sequentially constructed, the construction processes of the multiple-span channel-type trestle sections are the same, and the construction process of any one span channel-type trestle section is as follows: the construction of the steel pipe pile foundation of the channel type trestle section is firstly carried out, and then the channel type trestle body of the channel type trestle section is laid on the steel pipe pile foundation of the constructed channel type trestle section.

6. The construction method of the n-shaped sea-crossing temporary steel trestle according to claim 3, characterized in that: in the first step, after the bridge abutment (4) is built, a section steel distribution beam (15) is arranged on the bridge abutment (4), and one end of a transverse section steel beam (22-1) of the second steel approach bridge (3) is fixedly arranged on the section steel distribution beam (15).

7. The construction method of the temporary steel trestle shaped across the sea in the step 201 and the step 401 is characterized in that the main bridge section (1-1), the first connecting bridge section (1-2) and the second connecting bridge section (1-3) are all non-widened bridge sections, bridge bodies of the non-widened bridge sections comprise non-widened steel girders (20-1) and non-widened bridge decks (20-2) located right above the non-widened steel girders (20-1), and N Bailey girders (20-3) are erected between the non-widened steel girders (20-1) and the non-widened bridge decks (20-2), wherein N is a positive integer.

8. The construction method of a temporary steel trestle shaped across the sea according to claim 7, wherein in step 301, the first transition bridge section (1-4) and the second transition bridge section (1-5) each comprise a non-widened bridge section and two widened bridge sections arranged at both ends of the non-widened bridge section in a staggered manner, the two widened bridge sections of the first transition bridge section (1-4) are respectively connected with the first connecting bridge section (1-2) and the main bridge section (1-1), and the two widened bridge sections of the second transition bridge section (1-5) are respectively connected with the second connecting bridge section (1-3) and the main bridge section (1-1); the bridge body of the widened bridge section comprises a widened steel girder (24-1) and a widened bridge deck (24-2) located right above the widened steel girder (24-1), wherein M Bailey beams (20-3) are erected between the widened steel girder (24-1) and the widened bridge deck (24-2), M is a positive integer, and M is larger than N; the non-widened steel main beam (20-1) and the widened steel main beam (24-1) are respectively provided with a door-shaped limiting frame (20-4) used for limiting the mounting position of the Bailey beam (20-3).

9. The inverted V-shaped sea-crossing temporary steel trestle of claim 3, wherein: the steel trestle comprises a steel trestle main body, and is characterized in that a plurality of double steel pipe pile supports arranged at intervals and a plurality of single steel pipe pile supports arranged between two adjacent steel pipe pile supports are arranged below the trestle body of the steel trestle main body, a plurality of single steel pipe pile supports are uniformly arranged below the trestle body of the channel type trestle and below the trestle body of the connecting type trestle (8), the double steel pipe pile supports comprise at least four steel pipe piles (21-1) arranged in two rows, the single steel pipe pile supports comprise at least two steel pipe piles (21-1) arranged in one row, and the two adjacent steel pipe piles (21-1) are connected through a shear brace (21-2).

10. The main body structure of a temporary steel trestle of a Chinese character 'ji' shape across the sea of claim 9, characterized in that: the second dam (11) is provided with a second dam gate opening foundation (18), an auxiliary steel pipe pile support is arranged on the second dam gate opening foundation (18), the auxiliary steel pipe pile support comprises an auxiliary steel pipe pile (23-2) arranged on the second dam gate opening foundation (18), an auxiliary transverse steel beam (23-1) erected at the top of the auxiliary steel pipe pile (23-2) and parallel to the transverse steel beam (22-1), a concrete steel casing (23-3) is arranged at the bottom of the auxiliary steel pipe pile (23-2), and the auxiliary steel pipe pile (23-2) is connected with the adjacent steel pipe pile (21-1) through a cross brace (21-2).