CN105064196B - The fish belly I-shaped combination of prestressing force steel reinforced concrete simply supported girder bridge and its construction method of precast assembly - Google Patents

Abstract

The invention discloses a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge, which adopts a prefabricated fish-belly girder and a prefabricated concrete bridge deck, and adopts a ladle concrete member on the lower flange of the fish-belly I-shaped beam , the tension prestress in the concrete of the steel-clad concrete member of the lower flange greatly improves the bending stiffness of the steel girder, increases the precompressive stress of the bridge deck concrete after the completion of the bridge, and greatly increases the spanning capacity of the simply supported composite beam, And avoid the atmospheric exposure of the prestressed reinforcement, greatly improving the durability and reliability of the prestressed reinforcement. At the same time, the steel-concrete composite simply supported girder bridge of this structure can be easily transported, prefabricated, and assembled, and can fully meet the requirements of factory prefabricated components and on-site rapid installation. Accordingly, the inventor has also established a corresponding construction method, which is safe, high-quality, convenient and fast.

Description

Prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported beam bridge and its construction method

technical field

The invention belongs to the field of transportation bridge and culvert engineering, and in particular relates to a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported beam bridge and a construction method thereof.

Background technique

With the development of three-dimensional traffic infrastructure, urban bridge construction in densely populated areas or expressway cross-line construction is faced with the problem of uninterrupted traffic during the construction of bridge structures under heavy traffic conditions, which requires high construction safety and shortens the construction period. The requirements are short, and at the same time, the requirements for landscape and environmental protection must be taken into account.

Contents of the invention

The technical problem to be solved by the present invention is to provide a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge with convenient prefabrication of components and rapid on-site installation, and its construction method to meet the requirements of three-dimensional traffic construction with high safety, Short cycle, pay attention to the requirements of landscape and environmental protection.

In order to solve the above technical problems, the present invention adopts the following technical solutions: the prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge adopts prefabricated fish-belly girders and prefabricated concrete bridge decks, and the fish-belly I-shaped girder The lower flange adopts steel-clad concrete members, and the concrete of the lower-flange steel-clad concrete members is tensioned and prestressed.

The rise-span ratio of the steel-concrete composite simply supported girder bridge is controlled between 1/15-1/20, and the fish belly line of the lower flange is catenary or parabola.

The ratio of the height of the support section to the maximum mid-span height of the steel-concrete composite simply supported beam bridge is controlled between 1/2-2/3.

The construction method of the above-mentioned prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge comprises the following steps:

<1>Prefabricated concrete bridge deck and prefabricated fish-belly I-shaped steel girder in advance

When prefabricating fish-belly I-shaped steel beams, the steel-clad concrete components of the lower flange of the prefabricated unit are welded and processed, and the steel beam platform is used to make the beam platform, and the steel-clad concrete components of the lower flange, upper flange plates, webs, transverse stiffeners, Longitudinal stiffeners, support area webs, lower flanges of support members, support stiffeners, support transverse stiffeners, and support vertical stiffeners are welded into a single girder fish-belly I-shaped prefabricated unit; Binding ring-shaped stirrups in the concrete member and erecting steel bars form a reinforcement cage, and a bellows is installed, and the bellows passes through the diaphragm with holes in the lower flange member and passes through the support, and then welds the lower flange cladding plate; Concrete inclined formwork is installed at the edge, concrete is poured in the lower flange steel clad slab, and the concrete is cured;

<2>On-site hoisting

After the concrete is cured, the prefabricated fish-belly I-shaped prefabricated units are transported to the construction site and positioned and hoisted; between the multi-piece prefabricated fish-belly I-shaped prefabricated units, the mid-span hollow diaphragm and the support hollow diaphragm are used board connection;

<3> Tensile prestress

After the wet joint concrete curing of the concrete bridge deck is completed, the prestressed tendons in the steel-clad concrete member of the lower flange are stretched to form a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge.

The hoisting age of the precast concrete bridge deck is more than 180 days. The concrete bridge deck is equipped with bridge deck slot holes and reserved steel bars in the slot holes. Rebar connections are reserved inside.

A single fish-belly I-shaped prefabricated unit includes two fish-belly I-shaped steel beams, and the distance between the two fish-bellied I-shaped steel beams is 0.7-1.5 times the mid-span height of the I-shaped beam.

The bottom plate of the steel-clad concrete member of the lower flange and the web are welded together along the entire length of the beam, and the opening diaphragm is arranged at the lower part of each transverse stiffener of the web plate, and the web, bottom plate and cladding plate of the steel-clad concrete member of the lower flange Shear studs are arranged on the surface, and the concrete in the steel-clad concrete member of the lower flange is cast in-situ after the prefabrication of the entire I-beam prefabricated unit is completed.

The concrete in the steel-clad concrete member of the lower flange adopts fine-grained continuous graded crack-resistant concrete; the transverse wet joints of the bridge deck adopt quick-setting micro-expansion concrete, and the longitudinal wet joints use quick-setting concrete.

The shear stud group is arranged on the surface of the web and the top and bottom plates near the support; the upper surface of the upper flange adopts two types of long and short shear studs, the short shear studs are evenly distributed, and the evenly distributed short shear studs The length is 5-10cm; the long shear nails are clustered, and the length of the clustered long shear nails is 20-25cm.

The mid-span hollow diaphragm is composed of the upper chord of the mid-span hollow diaphragm, the lower chord of the mid-span hollow diaphragm, and the oblique mid-span hollow diaphragm; the support hollow diaphragm is composed of the support hollow diaphragm The upper chord of the diaphragm, the lower chord of the fastening diaphragm of the support, and the oblique composition of the hollow diaphragm of the support.

In order to meet the strict requirements of three-dimensional traffic construction, the inventor designed a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge. The lower flange of the girder is made of steel-clad concrete members, and the prestress is tensioned in the concrete of the lower flange steel-clad concrete members. The spanning capacity of the supporting composite beam is greatly increased, and the atmospheric exposure of the prestressed steel bars is avoided, and the durability and reliability of the prestressed steel bars are greatly improved. At the same time, the steel-concrete composite simply supported girder bridge of this structure can be easily transported, prefabricated, and assembled, and can fully meet the requirements of factory prefabricated components and on-site rapid installation. Accordingly, the inventor has also established a corresponding construction method, which is safe, high-quality, convenient and quick to use.

Description of drawings

Fig. 1 is the layout diagram of the prefabricated concrete bridge deck in the prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge of the present invention.

Fig. 2 is a layout diagram of reserved slots and steel bars on a single bridge deck in the prefabricated bridge deck of Fig. 1 .

Figure 3 is a detailed elevational view of the layout of the support and a schematic diagram of the support components.

Fig. 4 is a sectional view of a prefabricated unit of a single fish-belly I-shaped beam.

Fig. 5 is a schematic elevational view of the prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported beam bridge of the present invention.

Fig. 6 is a layout diagram of the cast-in-place concrete and the cross-section of the shear studs supported by the upper flange.

Fig. 7 is a perspective view of the steel-clad concrete member of the lower flange.

Fig. 8 is a perspective view of a prefabricated steel beam segment.

Fig. 9 is a schematic cross-sectional view of the mid-span of a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported beam bridge.

Fig. 10 is a cross-sectional schematic diagram of a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported beam bridge support.

Fig. 11 is an elevation view of a 48m main span of a certain city overpass bridge using the prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge of the present invention.

Fig. 12 is a mid-span cross-sectional view of a 48m main span of an urban overpass flyover.

Fig. 13 is a cross-sectional view of a 48m main span support of an urban overpass bridge.

Figure 14 is a cross-sectional view of the steel-clad concrete member of the lower flange of a 48m main span of an urban overpass flyover.

In the figure: 1 web, 2 prefabricated concrete bridge deck, 2a bridge deck groove hole, 2b reserved reinforcement in the prefabricated bridge deck groove hole, 2c reserved reinforcement around prefabricated bridge deck, 3 longitudinal stiffener, 4 lower Flange steel-clad concrete member, 4a open diaphragm in the lower flange steel-clad concrete member, 4b inner surface studs, 4c fine-grained continuous graded concrete body in the lower flange steel-clad concrete member, 4d lower flange steel-clad concrete member Clad plate, 4e lower flange steel-clad concrete member bottom plate, 4f lower flange steel-clad concrete member web, 4g lower flange steel-clad concrete member top plate, 5 transverse stiffeners, 6 support members, 6a support stiffeners, 6b support Component lower flange, 6c support longitudinal stiffener, 6d support vertical stiffener, 6e support member upper bending plate, 6f web below the steel-clad concrete flange in the support area, 7 steel beam end anchorage area plate Shear nail groups distributed on the surface, 8 upper flange plates, 9 support anchorage points of prestressed tendons, 10-span hollow diaphragm, 10a mid-span hollow diaphragm upper chord, 10b mid-span hollow diaphragm Slab lower chord, 10c mid-span hollow diaphragm slanting member, 10d mid-span hollow diaphragm gusset plate, 11 bridge deck wet joint, 11a bridge deck transverse wet joint, 11b bridge deck longitudinal wet joint, 12 Faster diaphragm on support, chord on upper diaphragm on diaphragm 12a, lower chord on diaphragm on diaphragm 12b, oblique rod on diaphragm on diaphragm 12c, diaphragm node on diaphragm 12d slab, 13 prestressed tendons inside the steel-clad concrete member of the lower flange, 14 small longitudinal beams erected under the prefabricated bridge deck, 15 cluster shear studs on the upper flange, 16 small longitudinal beams, evenly arranged on the chord surface of the vierendeel diaphragm shear studs, 17 evenly distributed shear studs on the upper surface of the upper flange, 18 concrete support on the upper surface of the upper flange, 19 upper bent plate on the lower flange of the support area, 20 fish-belly I-shaped beam prefabricated unit, 21 It is a single-piece fish-belly I-beam, with 22 bridge supports and 23 supports with concrete in the anchorage area.

detailed description

1. The basic structure of prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge

Prefabricated fish-web girders and prefabricated concrete bridge decks are used, steel-clad concrete members are used in the lower flange of fish-belly I-shaped beams, and prestressing is tensioned in the concrete of the lower flange steel-clad concrete members. The rise-span ratio is controlled between 1/15-1/20, where the rise-span ratio is defined as the ratio of the height of the I-shaped composite beam span to the span, and the fish belly line of the lower flange is a catenary or parabola ; The ratio of the section height of the support to the maximum height of the span is controlled between 1/2-2/3. The length control of the web along the main girder near the support area is determined according to the design shear force of the main girder, and the shear force near the support should satisfy:

V≤t _f h _f f _v +0.75A _g f _g tanθ+A _s f _s tanθ

In the formula, V is the design shear force, tf is the thickness of the web, hf_ is the height of the web, f _v is the design value of the shear strength of the web, Ag is the total area of the steel strand, fg is the design tensile strength of the steel strand value, θ is the angle between steel strand or ladle concrete flange and the horizontal direction, As is the steel area of ladle flange, fs is the design value of tensile strength of ladle flange steel.

2. Construction method of prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge

<1>Prefabricated concrete bridge deck and prefabricated fish-belly I-shaped steel girder in advance

The hoisting age of the precast concrete bridge deck 2 is more than 180 days. The concrete bridge deck is provided with bridge deck slot holes 2a and rebars 2b are reserved in the slot holes. Connect with the reserved steel bar 2b in the grooved hole (see Figure 1 and Figure 2).

When prefabricating fish-belly I-shaped steel beams, the steel-clad concrete member 4 of the lower flange of the prefabricated unit is welded and processed, and the steel beam frame is used to make the steel-clad concrete member 4 of the lower flange, the upper flange plate 8, the web 1, Transverse stiffener 5, longitudinal stiffener 3, upper bent plate 6e of support member, lower flange of support member 6b, support stiffener 6a, support longitudinal stiffener 6c, support vertical stiffener 6d (see Figure 3 ) is welded into a prefabricated unit 20 of a single fish-belly I-shaped beam (Fig. 4); in the lower flange steel-clad concrete member 4, ring-shaped stirrups and vertical steel bars are bound to form a reinforcement cage, and bellows are arranged, and the bellows pass through the lower The open diaphragm 4a in the steel-clad concrete member of the flange passes through the support, and then welds the cladding plate 4d of the steel-clad concrete member of the lower flange; Continuously graded concrete body 4c, concrete curing;

Among them, the prefabricated unit 20 of a single fish-belly I-shaped section beam includes two pieces of fish-belly I-shaped steel beams 21 (Fig. 4, Fig. 5), and the distance between the two pieces of fish-belly I-shaped steel beams is 100% of the mid-span height of the I-shaped beam. 0.7-1.5 times.

The bottom plate of the steel-clad concrete member of the lower flange and the web are welded together along the entire length of the beam, and the opening diaphragm is arranged at the lower part of each transverse stiffener of the web plate, and the web 4f, the bottom plate 4e and the cladding plate of the steel-clad concrete member of the lower flange The inner surface studs 4b are arranged on the inner surface of 4d (the cladding plate 4d is not welded first), and the concrete in the steel-clad concrete member of the lower flange is cast in place after the prefabrication of the entire I-beam prefabricated unit 20 is completed. The use of steel clad slabs can maximize the convenience of concrete pouring construction, and effectively improve the integrity of the lower flange concrete and steel lower flange. See Figure 6, Figure 7 and Figure 8

Concrete 4c in the steel-clad concrete member of the lower flange adopts fine-grained continuous graded crack-resistant concrete to effectively wrap the bellows and prevent cracks; the transverse wet joint 11a of the bridge deck adopts quick-setting micro-expansion concrete, and 11b uses quick-setting concrete to obtain a certain preload in the longitudinal direction of the bridge deck, which is beneficial to the overall stress of the bridge structure, and can effectively prevent wet joints and bridge deck concrete cracking, and improve the durability of the bridge deck. When the height of the beam section near the support is small, the steel plate and web of the lower flange steel-clad concrete member near the support can be made of high-strength steel, but the maximum strength should not exceed 2 times the strength of the main steel. When the anti-sectional height is small and the shear strength of the steel beam is insufficient, high-strength steel can be considered to withstand greater shear force.

The shear nail group 7 is arranged on the surface of the web and the top and bottom plates near the support to ensure the connection between the concrete and the steel beam in the anchorage area at the end; The force nails are evenly distributed, and the upper surface of the upper flange is evenly distributed. The length of the shear nails 17 is 5-10cm, which is used to connect the concrete support 18 of the cast-in-place prefabricated upper flange slab; the long shear nails are clustered, and the upper flange The cluster-type long shear nails 15 are 20-25cm in length and are used to connect the prefabricated concrete bridge deck according to the position distribution of the grooved holes 2a of the prefabricated bridge deck as shown in Fig. 6 .

<2>On-site hoisting

After the concrete is cured, the prefabricated fish-belly I-shaped prefabricated units are transported to the construction site and positioned and hoisted; between the multi-piece prefabricated fish-belly I-shaped prefabricated units, the mid-span hollow diaphragm and the support hollow diaphragm are used board connection;

The mid-span hollow diaphragm 10 is composed of the mid-span hollow diaphragm upper chord 10a, the mid-span hollow diaphragm lower chord 10b, and the mid-span hollow diaphragm oblique 10c; the support hollow diaphragm 12 It is composed of the upper chord 12a of the hollow type diaphragm of the support, the lower chord 12b of the hollow type diaphragm of the support, and the oblique 12c of the hollow type diaphragm of the support. See Figure 9 and Figure 10.

<3> Tensile prestress

After the wet joint concrete curing of the concrete bridge deck is completed, the prestressed tendons in the steel-clad concrete member of the lower flange are stretched to form a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge.

3. Application of prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge

The main span of a certain city overpass bridge is 48m, two-way six-lane, the transverse design width of the bridge is 21.5m, and the lower part spans the eight-lane main road of the city. Scheme of web girder prestressed steel-concrete composite simply supported girder bridge.

The main span is 48m, the span ratio is 1/16, the mid-span steel girder height is 3.0m, the support thickness is 0.1m, the bridge deck thickness is 0.2m, and the steel girder height at the support part is 1.5m. The distance between the single-piece steel beams is selected as 3m, the left and right cantilever cantilever is 2.2m, and the middle cantilever is 2.0m. A total of 8 prestressed reinforcement holes are set in the steel clad concrete member of the lower flange, and each hole adopts a bundle of 7φ15.2mm1860 prestressed Stressed strands. Three fish-belly I-shaped beam prefabricated units are used in the horizontal direction. The elevation of the main span of the bridge is shown in Figure 11, the mid-span cross-section is shown in Figure 12, the support cross-section is shown in Figure 13, and the cross-section of the steel-clad concrete member of the lower flange is shown in Figure 14.

The method adopted in the present invention completes the hoisting of the main span steel girder within 2-3 days after the prefabrication of the steel girder is completed, and hoistes the concrete bridge deck at night. City bridge construction hinders traffic.

Claims (9)

1. A construction method of a prefabricated fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge, characterized in that a prefabricated fish-belly girder and a prefabricated concrete bridge deck are used, and the lower flange of the fish-belly I-shaped beam Steel-clad concrete members are used to tension prestress in the concrete of the lower flange steel-clad concrete members; specifically, the following steps are performed: <1>Prefabricated concrete bridge deck and prefabricated fish-belly I-shaped steel girder in advance When prefabricating fish-belly I-shaped steel beams, the steel-clad concrete components of the lower flange of the prefabricated unit are welded and processed, and the steel beam platform is used to make the beam platform, and the steel-clad concrete components of the lower flange, upper flange plates, webs, transverse stiffeners, Longitudinal stiffeners, support area webs, lower flanges of support members, support stiffeners, support transverse stiffeners, and support vertical stiffeners are welded into a single girder fish-belly I-shaped prefabricated unit; Binding ring-shaped stirrups in the concrete member and erecting steel bars form a reinforcement cage, and a bellows is installed, and the bellows passes through the diaphragm with holes in the lower flange member and passes through the support, and then welds the lower flange cladding plate; Concrete inclined formwork is installed at the edge, concrete is poured in the lower flange steel clad slab, and the concrete is cured; <2>On-site hoisting After the concrete is cured, the prefabricated fish-belly I-shaped prefabricated units are transported to the construction site and positioned and hoisted; between the multi-piece prefabricated fish-belly I-shaped prefabricated units, the mid-span hollow diaphragm and the support hollow diaphragm are used board connection; <3> Tensile prestress After the wet joint concrete curing of the concrete bridge deck is completed, the prestressed tendons in the steel-clad concrete member of the lower flange are stretched to form a prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported girder bridge. 2. The construction method according to claim 1, characterized in that: the hoisting age of the prefabricated concrete bridge deck is more than 180 days, the concrete bridge deck is provided with bridge deck grooved holes and steel bars are reserved in the grooved holes, During hoisting, the cluster shear nails on the upper flange of the cast-in-place concrete are connected to the reserved steel bars in the grooved holes. 3. The construction method according to claim 1, characterized in that: the single girder fish-belly I-shaped prefabricated unit includes two fish-belly I-shaped steel beams, and the distance between the two fish-belly I-shaped steel beams is I-shaped 0.7-1.5 times the mid-span height of the beam. 4. The construction method according to claim 1, characterized in that: the bottom plate of the lower flange steel-clad concrete member and the web are welded together along the entire length of the beam, and holes are set at the lower parts of the transverse stiffeners of the web. For the diaphragm, shear studs are arranged on the inner surface of the web, bottom plate and cladding plate of the steel-clad concrete member of the lower flange, and the concrete in the steel-clad concrete member of the lower flange is cast-in-place after the prefabrication of the entire I-beam prefabricated unit is completed. 5. The construction method according to claim 1, characterized in that: the concrete in the lower flange ladle concrete member adopts fine-grained continuous graded crack-resistant concrete; the transverse wet joint of the bridge deck adopts quick-setting micro Expansive concrete, quick-setting concrete is used for longitudinal wet joints. 6. The construction method according to claim 1, characterized in that: shear nail groups are arranged on the surface of the web and the top and bottom plates near the support; the upper surface of the upper flange adopts two kinds of long and short shear force Nail arrangement, the short shear nails are evenly distributed, and the length of the evenly distributed short shear nails is 5-10cm; the long shear nails are clustered, and the length of the clustered long shear nails is 20-25cm. 7. The construction method according to claim 1, characterized in that: said mid-span hollow diaphragm is composed of the upper chord of the mid-span hollow diaphragm, the lower chord of the mid-span hollow diaphragm, and the mid-span hollow diaphragm. The clapboard is composed of slant; the fasting type diaphragm of the support is composed of the upper chord of the fasting type diaphragm of the support, the lower chord of the fasting type diaphragm of the support, and the oblique composition of the fasting type diaphragm of the support. 8. The prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported beam bridge obtained by the construction method of claim 1 is characterized in that: the rise-span ratio of the steel-concrete composite simply supported beam bridge is controlled at 1/15 Between -1/20, the fish belly line of the lower flange is catenary or parabola. 9. The prefabricated and assembled fish-belly I-shaped prestressed steel-concrete composite simply supported beam bridge according to claim 8, characterized in that: the height of the support section of the steel-concrete composite simply supported beam bridge is between the maximum height of the mid-span The ratio is controlled between 1/2-2/3.