Construction method of upper-span bridge middle pier in highway widening and traffic keeping state

Abstract

The invention provides a construction method for a middle pier of an overpass bridge in a widening and traffic keeping state of an expressway. The construction method comprises the following steps: dividing a site; issuing traffic information; traffic layout; adjusting a marked line; performing protection installation; mechanically entering the field; breaking and removing a middle division belt; pile foundation construction; constructing a bearing platform; constructing a bent cap in a bracket erection process form; carrying out support edge protection construction; and erecting the prefabricated box girder. By means of the construction method, construction of the upper-span bridge middle piers can be orderly, effectively and rapidly conducted in the state that the two sides of the expressway are widened and traffic is guaranteed, the expressway quality and safety acceptance standards are met, the requirements for whole-line staged traffic guiding and changing nodes and efficient construction are met, the traffic pressure on the existing expressway is reduced, and traffic safety is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of building construction, and in particular relates to a method for constructing a middle pier of an upper span bridge in a highway widening and traffic maintenance state. Background Art

[0002] Under the background of rapid development of national economy, some existing highways no longer meet the requirements of safe and comfortable driving. Therefore, it has become a new trend to renovate, expand and upgrade existing highways. Especially in the process of widening the two sides of the highway near the urban area, how to safely, efficiently and quickly complete the construction of the highway overpass has become an urgent problem to be solved. At this time, it is a conventional method to build a highway overpass under the state of two-way traffic maintenance; similarly, the construction task of the middle pier of the new overpass must be completed in stages with the conversion of main line and branch line traffic, and the construction must be carried out quickly. Therefore, how to minimize the impact of the middle pier construction on the existing highway and ensure the basic traffic capacity of the road under the condition of urgent time and heavy construction tasks has become a problem to be solved. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a method for constructing the middle pier of an upper span bridge when the expressway is widened and opened to traffic. The method can quickly and orderly and effectively carry out the construction of the middle pier of an upper span bridge when the expressway is widened and opened to traffic on both sides of the expressway, thereby meeting the expressway quality and safety acceptance standards, satisfying the phased traffic diversion nodes of the entire line, and achieving efficient construction, reducing the pressure on the existing expressway traffic and ensuring driving safety.

[0004] The present invention achieves the above technical objectives through the following technical means.

[0005] A method for constructing a middle pier of an upper span bridge in a highway widening and traffic maintenance state comprises the following steps: Step 1: Construction site division; Step 2: Release construction information and early warning information, and use map software to push the construction section occupancy situation; Step 3: Traffic layout; Step 4: Adjust the marking line; Step 5: Installation of protection in the construction area; Step 6: Machinery enters the site; Step 7: Break the middle band; Step 8: Pile foundation construction; Step 9: Capping construction; Step 10: Construction of cap beam; Step 11: Construction of support edge protection; Step 12: Erection of prefabricated box beams.

[0006] Furthermore, in step 1, according to the total distance between multiple overpasses, multiple mid-pier construction work areas are divided with 3km as one work area; and in combination with the characteristics of the project at this stage, the traffic organization area of ​​the work area is divided into six parts: warning area, speed limit 80km / h, length 2000m; upstream transition area, speed limit 60km / h, length 300m; buffer area, speed limit 60km / h, length 200m; working area, speed limit 60km / h, length 3000m; downstream transition area and termination area, speed limit 60km / h, length 50m.

[0007] Furthermore, in step 4, during the construction of the temporary markings, the first lane and part of the second lane, as well as the second lane and the emergency lane are alternately closed; when the first lane and part of the second lane are occupied, vehicles use the remaining lanes to pass; when the second lane and the emergency lane are occupied, vehicles use the first lane to pass; the temporary markings are divided into lane markings, oscillating markings, guide arrows and road surface text.

[0008] Furthermore, in step 5, the construction area is protected by a "three-layer combination", which includes fences, water barriers, and traffic cones from the inside to the outside, and flood prevention sandbags are added to the inside of the fence, and flashing lights are installed on the fence to indicate the outline.

[0009] Furthermore, in step 8, based on the condition of two-way traffic, the plan layout of the pile foundation construction site is: crane + steel cage transport vehicle + impact drill + leakproof pool + mud box + closed mud transport vehicle, the front of the crane faces north and the rear of the vehicle faces south, and the position is adjusted to ride on the center dividing strip during lifting operations; the mud circulation system uses two mud boxes for circulation operations, one main and one secondary to prevent mud overflow; when the mud box enters the site, one mud box is filled with water in advance as water for pile foundation drilling, and subsequent water is supplied by a water truck; during drilling, the mud circulation system circulates from the hole through the mud pump to the mud box; to prevent the mud pump from being damaged and leaking slurry, leakproof sandbags are arranged at the enclosures on both sides to prevent the mud from spilling onto the roadway and affecting driving safety, and a water truck is configured to flush the mud in the enclosure.

[0010] Furthermore, during the concrete pouring construction of the pedestal and the cap beam, the pump station is located outside the existing road and crosses the highway to pour concrete. The pump pipe mouth is wrapped with geotextile and firmly tied with steel wire to prevent concrete dripping.

[0011] Furthermore, in step 10, after the pile foundation construction is completed, half of the highway is closed, and the lower structure of the middle pier is constructed on the half-closed site; when constructing the pedestal, a blasting machine is used to first pierce the four corners of the pedestal to set the positions. Considering that the pedestal foundation pit is the location of the original highway center dividing strip, the soil is compacted gray soil, and slope excavation is more difficult, which affects traffic. The foundation pit is excavated vertically along the edge of the pedestal to eliminate the need for formwork support; finally, concrete pouring is carried out.

[0012] Furthermore, in step 11, the cap beam is erected using a support erection process, and the distance from the center of the cap beam to the right side of the support is ensured to be 1.3m; when the cap beam is erected, the position of the buckle node is marked to ensure the accuracy of the point position and size, and a transverse main beam I-beam is set on the top of the support. The main beam I-beam is cantilevered 30cm to the side of the driving channel as a cantilevered operating platform. The cantilevered operating platform and the top of the left support are fully covered with scaffolding for construction workers to walk and work, and a ladder cage is also installed on one side of the support, which is connected to the scaffolding for construction workers to walk on. Workers crawl up and down; small beams are set longitudinally on the upper edge of the main beam I-beam, and the small beams are made of square wood; the support foundation above the concrete of the middle pier cap is made of plain fill and C20 concrete; horizontal protective nets are set on the upper and lower parts of the support; steel bars are welded to the outer edge of the cantilevered end of the main beam I-beam, and bamboo plywood is placed vertically as hard edge protection; reflective signs and light strips are also set at the corners of the support for outline to prevent vehicle collision; after the support structure is fully erected, formwork, steel bar tying, concrete pouring, and other maintenance processes are carried out.

[0013] Furthermore, in step 12, a PVC casing with a diameter of 30 mm and a length of 20 cm is embedded as a reserved hole before pouring the cap beam. The holes are 20 cm inward in the long and short sides of the cap beam, and there are 4 holes in total. After the cap beam concrete is cured, before the pedestal stone construction, 4 threaded steel bars with a diameter of 28 mm and a length of 1.5 m are inserted into the holes, and steel wire ropes are used to form a circle as support pedestal stones and edge protection during support installation to prevent falling from heights. Finally, the erection of prefabricated box beams is carried out alternately.

[0014] Furthermore, in step 13, in the half-width closed state, the precast beams on the closed side are first erected, and then after the half-width construction is completed, the traffic on this side is opened; the other half-width road is closed, and the precast beams on the half-width are erected.

[0015] The present invention has the following beneficial effects: The present invention aims to disclose a method for constructing the middle pier of an upper span bridge under the state of widening and maintaining traffic on a highway. The method for constructing the middle pier of an upper span bridge under the state of bidirectional maintenance of traffic is described through four stages, namely, phased traffic diversion, pile foundation construction of two overtaking lanes, construction of a half-closed lower structure, and alternating erection of prefabricated beams. The construction method provided by the present invention solves the problem of how to quickly construct an upper span bridge under various traffic diversion and maintenance conditions on a highway. During the diversion stage, the upper span bridge on the highway is delivered for use as early as possible, and the impact of the construction on the surrounding existing highways and local roads is reduced as much as possible, thereby ensuring the basic traffic capacity of the road. The present invention accelerates the process of dismantling and rebuilding the upper span bridge through four stages, namely, simulation of phased traffic diversion, adjustment of pile foundation construction of two overtaking lanes, upgrading of the construction of a half-closed lower structure, and optimization of alternating erection of prefabricated beams. It has promotion value and can allow more renovation and expansion projects to adopt this intensive, efficient and safe construction method when constructing the upper span bridge. By utilizing the present invention, the construction of the middle pier of the upper bridge can be carried out in an orderly, effective and rapid manner while widening and maintaining traffic on both sides of the expressway, thereby meeting the expressway quality and safety acceptance standards, satisfying the phased traffic diversion nodes of the entire line, achieving efficient construction, reducing the pressure on existing expressway traffic, and ensuring driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of temporary marking construction for the middle pier; Figure 2 This is the enclosure layout of the middle pier pile foundation work area; Figure 3 This is the layout drawing of the working surface for the middle pier pile foundation construction; Figure 4 This is the plan layout of the construction site of the middle pier pile foundation; Figure 5 This is the front section view of the formwork-free support of the middle pier cap; Figure 6 This is the top view of the formwork-free support of the middle pier cap; Figure 7 This is the front section view of the small eccentricity of the middle pier cap beam support; Figure 8 This is a top view of the slightly eccentric middle pier cap beam support.

[0017] Fig. 9 This is the process flow chart for the construction of the middle pier of the upper span bridge when the expressway is widened and maintained.

[0018] In the figure: 1-cap pedestal; 2-protection pier; 3-customized protection mesh; 4-main beam I-beam; 5-plain fill; 6-C20 concrete; 7-horizontal protection net; 8-hard edge protection; 9-small beam; 10-ladder cage; 11-rebar; 12-scaffolding board. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto. The directions indicated by "east", "west", "south", "north", "left" and "right" in the present invention are based on the descriptions shown in the accompanying drawings and actual construction projects, and are only for the purpose of more clearly showing the content of the scheme, and cannot be understood as limiting the present invention.

[0020] Reference Fig. 9 The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining the traffic of the expressway according to the present invention comprises the following steps: Step 1: Site division; According to the total distance between multiple overpasses, the operation area is divided into multiple mid-pier construction operation areas with 3km as one operation area; and combined with the characteristics of this stage of the project, the traffic organization area of ​​the operation area is divided into six parts: Figure 1 , 2 The speed limit in the warning zone S is 80km / h and the length is 2000m; the speed limit in the upstream transition zone Ls is 60km / h and the length is 300m; the speed limit in the buffer zone H is 60km / h and the length is 200m; the speed limit in the working zone G is 60km / h and the length is 3000m; the speed limit in the downstream transition zone Lx and the termination zone Z is 60km / h and the length is 50m.

[0021] Step 2: Information release; At each stage of construction, report to the highway management center and information release platform seven days before implementation, use traffic broadcasts, highway electronic information boards, networks (public accounts) and other platforms to release construction information and early warning information; use mobile map software to push the construction section occupancy status. According to the characteristics of this project, it is necessary to occupy the first lane of both directions, and the occupied lane status can be prompted on the map software.

[0022] Step 3: Traffic layout; Before the deployment of traffic facilities, traffic cones shall be used to channelize lanes according to the traffic organization plan and drawings, guide vehicles to reduce speed, and set up traffic guidance facilities and closure facilities. After the traffic safety facilities are set up, they can be implemented only after confirmation by the relevant management unit.

[0023] Step 4: Adjust the marking line; Before the implementation of the middle pier, the markings need to be adjusted in advance. During the construction of temporary markings, the first lane and part of the second lane, as well as the second lane and the emergency lane, need to be closed alternately. When occupying the first lane and part of the second lane, vehicles use the remaining lanes for passage; when occupying the second lane and the emergency lane, vehicles use the first lane for passage; during the period of occupying the lanes, the remaining traffic lanes are not less than 4m. Temporary markings are divided into lane markings, oscillating markings, guide arrows and road text.

[0024] Step 5: Protective installation; like Figure 3 As shown, the construction area is protected by a "three-layer combination", which consists of fences, water barriers, and traffic cones from the inside to the outside. The fences prevent construction materials from rolling onto the road surface, and flood prevention sandbags are added to the inside of the fences to enhance the anti-collision level and stability. Flashing lights are installed on the fences to indicate the outline.

[0025] Step 6: Machinery enters the site; After the vehicle reaches the target construction site, it drives into the closed section and reverses into the construction site. After completion, it drives from the closed area into the traffic section. Professional flag-waving personnel must be arranged to direct the entry and exit. The entry and exit of construction vehicles must not affect the driving of vehicles on the normal traffic section.

[0026] Step 7: Break the middle band; In this embodiment, the middle piers of many newly built overpasses are located in the median strip of the highway. Due to the special location and narrow site, it is calculated that in order to meet the actual construction conditions on site, the demolition length of the median strip is 40m. The demolition operation of the median strip is carried out within the enclosure. The demolition range is 27m north from the center of the north end pile and 13m at the south end. Excavators and jackhammers are used to cooperate in demolition to ensure the working range of crane lifting and drilling rigs.

[0027] Step 8: Pile foundation construction; Reference Figure 4 , considering that under the condition of two-way traffic, pile foundation construction cannot be carried out according to conventional practices, and there are great risks of leakage and scattering in mud disposal and concrete pouring; therefore, the site plan layout of this embodiment is crane + steel cage transport vehicle + impact drill + leakproof pool + mud box + closed mud transport vehicle, and the crane station is north-south, that is, the front of the vehicle faces north and the parking position faces south. During the lifting operation, the station is adjusted to ride on the middle dividing belt to facilitate lifting; the mud circulation system uses two mud boxes for circulation operation, one main and one secondary to prevent mud overflow, and the size of the mud box is 2.6m×6m×3m; when the mud box enters the site, one mud box is filled with water in advance as water for pile foundation drilling, and subsequent water is supplied by a water truck; during drilling, the mud circulation system circulates from the hole through the mud pump to the mud box. In order to prevent the mud pump from being damaged and leaking slurry, 5m leak-proof sandbags are arranged at the enclosures on both sides to prevent the mud from spilling onto the roadway and affecting driving safety; and a water truck is provided to flush the mud inside the enclosure.

[0028] Step 9: Construction of platform 1; Reference Figure 5 , 6After the pile foundation construction is completed, half of the highway is closed, and the lower structure of the middle pier is constructed on the half-closed site; during the construction of cap 1, the blasting machine is used to first pierce the four corners of cap 1 to set the position. Considering that the foundation pit of cap 1 is the location of the original median strip of the highway, the soil is compacted gray soil, and it is difficult to excavate the slope, which affects the traffic. Therefore, the foundation pit is excavated vertically along the edge of cap 1 to eliminate the need for formwork support; finally, concrete pouring is carried out. During the concrete pouring, the pump station is located on the outside of the existing road, crossing the highway for concrete pouring. The pump pipe mouth is wrapped with geotextile and tied firmly with steel wire to prevent concrete dripping.

[0029] Step 10: Construction of cap beam; Reference Figure 7 , 8 As the pier is square, the cap beam is erected by the scaffolding technology. Due to the special position of the center dividing strip, the outer side of the east curb is close to the traffic lane. In order to prevent overloaded vehicles from colliding with the bracket, the distance from the center of the cap beam to the right side of the bracket is 1.3m, that is, the inner side of the white line of the curb. When the cap beam is erected, the position of the disc buckle node is marked to ensure the accuracy of the point position and size. As it is impossible to erect an extra row of brackets on the right side for pedestrian passage, a transverse main beam I-beam 4 is set on the top of the bracket. The main beam I-beam 4 is cantilevered 30cm to the right as a cantilevered operating platform. The cantilevered operating platform and the top of the left bracket are fully covered with scaffolding boards 12 for construction workers to walk and work. A ladder cage 10 is also installed on one side of the bracket. The ladder cage 10 is connected to the scaffolding board 12 for The construction workers crawled up and down; a small beam 9 was set longitudinally on the main beam I-beam 4, and the small beam 9 was made of 10cm×10cm square wood; the support foundation above the concrete of the middle pier cap was made of plain fill 5 and 15cm thick C20 concrete 6; horizontal protection nets 7 were set on the upper and lower parts of the support; a steel bar 11 with a diameter of 25mm and a length of 1.2m was welded on the outer edge of the cantilevered end of the main beam I-beam 4, and a 1.2m high and 15mm thick bamboo plywood was placed vertically as a hard edge protection 8; reflective signs and light strips were also set at the corners of the support to indicate the outline and prevent vehicle collision; after all the above support structures were erected, other processes such as formwork, steel bar tying, concrete pouring, and maintenance were carried out, and the concrete pouring method was the same as the cap 1. The main beam I-beam 4 was made of No. 14 I-beam.

[0030] Step 11: Construction of support edge protection; Before pouring the cap beam, PVC sleeves with a diameter of 30mm and a length of 20cm are embedded as reserved holes. The holes are located on the block, 20cm inward from the long and short sides, with a total of 4 holes. After the cap beam concrete is cured, before the pad stone construction, use the holes reserved when pouring the cap beam to insert 4 threaded steel bars with a diameter of 28mm and a length of 1.5m into the holes, and use a steel wire rope with a diameter of 8mm to form a circle as the support pad stone and the edge protection during the support installation to prevent falling from heights; finally, the prefabricated box beams are erected alternately.

[0031] Step 12: Erection of prefabricated box beams; When half of the road is closed, the precast beams on the closed side are erected first, and then after the construction of half of the road is completed, the traffic on this side is opened; the other half of the road is closed and the precast beams on the other half are erected.

[0032] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A method for constructing the middle pier of an upper span bridge in a highway widening and traffic maintenance state, characterized in that: The process includes the following: Step 1: Construction site division; Step 2: Release construction information and early warning information, and use map software to push the construction section occupancy situation; Step 3: Traffic layout; Step 4: Adjust the marking line; Step 5: Installation of protection in the construction area; Step 6: Machinery enters the site; Step 7: Break the middle band; Step 8: Pile foundation construction; Step 9: Construction of the foundation (1); Step 10: Cap beam construction; Step 11: Construction of support edge protection; Step 12: Erection of prefabricated box beams.

2. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1 is characterized in that: In the step 1, multiple mid-pier construction work areas are evenly divided according to the total distance between multiple upper span bridges; and the traffic organization area of ​​the work area is divided into six parts in combination with the characteristics of the project at this stage: a warning area with a speed limit of 80km / h and a length of 2000m; an upstream transition area with a speed limit of 60km / h and a length of 300m; a buffer area with a speed limit of 60km / h and a length of 200m; In the working area, the speed limit is 60km / h and the length is 3000m; in the downstream transition zone and termination zone, the speed limit is 60km / h and the length is 50m.

3. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1 is characterized in that: In step 4, during the construction of the temporary markings, the first lane and part of the second lane, as well as the second lane and the emergency lane are alternately closed; the temporary markings are divided into lane markings, oscillating markings, guide arrows and road surface text.

4. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1 is characterized in that: In step 5, the construction area is protected by a "three-layer combination", which includes fences, water barriers, and traffic cones from the inside to the outside. Flood prevention sandbags are added to the inside of the fence, and flashing lights are installed on the fence to indicate the outline.

5. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1 is characterized in that: In step 8, based on the condition of two-way traffic, the plan layout of the pile foundation construction site is: crane + steel cage transport vehicle + impact drill + leakproof pool + mud box + closed mud transport vehicle, the front of the crane faces north and the rear of the crane faces south, and the position is adjusted to ride on the center dividing strip during lifting operations; the mud circulation system uses two mud boxes for circulation operations, one main and one secondary to prevent mud overflow; when the mud box enters the site, one mud box is filled with water in advance as water for pile foundation drilling, and subsequent water is supplied by a water truck; during drilling, the mud circulation system circulates from the hole through the mud pump to the mud box; in order to prevent the mud pump from being damaged and leaking slurry, leakproof sandbags are arranged at the enclosures on both sides to prevent the mud from spilling onto the roadway and affecting driving safety, and a water truck is configured to flush the mud in the enclosure.

6. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1 is characterized in that: During the concrete pouring construction of the cap (1) and the cap beam, the pump station is located outside the existing road and crosses the highway to pour concrete. The pump pipe mouth is wrapped with geotextile and tied firmly with steel wire to prevent concrete dripping.

7. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1 is characterized in that: In step 10, after the pile foundation construction is completed, the half-width highway is closed, and the lower structure of the middle pier is constructed on the half-width closed site; when the cap (1) is constructed, the four corners of the cap (1) are firstly set with a blasting machine. Since the foundation pit of the cap (1) is located at the original center dividing strip of the highway, the soil is compacted gray soil, and the slope excavation is difficult and affects traffic. Therefore, the foundation pit is vertically excavated along the edge range of the cap (1) to avoid formwork support; finally, concrete pouring is carried out.

8. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1 is characterized in that: In step 11, the cap beam is erected using a support frame process, and the distance from the center of the cap beam to the right side of the support frame is ensured to be 1.3 m. When the cap beam is erected, the position of the buckle node is marked to ensure the accuracy of the point position and size. A transverse main beam I-beam (4) is set on the top of the support frame. The main beam I-beam (4) is cantilevered 30 cm to the side of the driving channel as a cantilevered operating platform. The cantilevered operating platform and the top of the left support frame are fully covered with scaffolding boards (12) for construction workers to walk and work. A ladder cage (10) is also installed on one side of the support frame. The ladder cage (10) is connected to the scaffolding board (12) for construction workers to go up and down. Crawling; a small beam (9) is longitudinally arranged on the upper edge of the main beam I-beam (4), and the small beam (9) is made of square wood; the support foundation above the concrete of the middle pier cap is made of plain fill (5) and C20 concrete (6); horizontal protection nets (7) are arranged on the upper and lower parts of the support; steel bars (11) are welded to the outer edge of the cantilevered end of the main beam I-beam (4), and bamboo plywood is placed vertically as hard edge protection (8); reflective signs and light strips are also arranged at the corner points of the support for delineation to prevent vehicle collision; after the support structure is fully erected, formwork, steel bar tying, concrete pouring, and other maintenance processes are carried out.

9. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1, characterized in that: In step 12, multiple PVC sleeves are embedded in advance to make reserved holes before pouring the cap beam. After the cap beam concrete is cured, threaded steel bars are inserted into the holes before the pedestal stone is constructed, and steel wire ropes are used to form a circle to serve as support pedestal stones and edge protection during support installation to prevent falling from heights. Finally, the erection of prefabricated box beams is carried out alternately.

10. The method for constructing the middle pier of the upper span bridge in the state of widening and maintaining traffic of the expressway according to claim 1, characterized in that: In step 13, in the half-width closed state, the precast beams on the closed side are first erected, and then after the half-width construction is completed, the traffic on this side is opened; the other half-width road is closed and the precast beams on the half-width are erected.

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