CN201801806U - Externally-prestressed continuous beam bridge with first simple supporting and second continuation - Google Patents

Abstract

An externally prestressed continuous girder bridge that is simply supported first and then continuous, comprising a concrete beam, the concrete beam adopts an externally prestressed beam that is simply supported first and then continuous, and the two sides of the concrete beam are symmetrically installed with in vitro Prestressed bundle, the concrete beam includes a wing plate, a web, a horseshoe and a diaphragm, the wing plate, the web and a horseshoe are integrated and have a T-shaped cross section, and multiple pieces of the beam are arranged on the concrete beam Said diaphragm, said diaphragm is provided with external prestressed tunnels, and each span on both sides of said concrete beam is provided with a plurality of inter-span steering blocks, the utility model adopts the above-mentioned construction technology to replace Convenience, low frictional loss, light beam lifting weight, easy assembly construction, and thin bridge deck pavement.

Description

A kind of externally prestressed continuous girder bridge with simple support first and then continuous

technical field

The utility model relates to a beam bridge construction technology, in particular to an external prestressed continuous beam bridge which is simply supported first and then continuous.

Background technique

With the rapid development of high-grade highways in my country, the quality requirements of bridges connecting expressways have been increased accordingly, and bridge construction technology is extremely critical. The current status is that for high-grade highway bridges with small spans, prefabricated reinforced concrete slab girders are mostly used, and bridges with medium spans are in the form of prestressed concrete T (box) girders. For stressed concrete continuous girder bridges, the current construction method mainly adopts balanced cantilever pouring method or assembly method. However, because the construction of cast-in-place continuous beams is complicated, labor-intensive and time-consuming, people have always hoped to combine the mass prefabrication of simply supported beams with the superior performance of continuous beams, and realize the mass prefabrication of beams or slabs to speed up the continuous beams. Construction This is the method we often say "simply supported first and then continuous construction". The simply supported and then continuous bridge structure has the following characteristics: (1) high rigidity, small deformation, less expansion joints and comfortable driving; (2) the prestressed steel tendons of the simply supported Prestressed steel tendons are arranged and stretched on concrete beams, and only lifting equipment is needed to lift concrete beams, which reduces construction equipment and avoids obstacles on the ground caused by tensioning prestressed steel tendons; (3) prefabricated beams can be used Standard components, factory unified production and management, is conducive to technical operations, saves construction time, shortens the construction period, and improves economic benefits. the

Investigation and analysis of existing highway bridges reveals two major problems: on the one hand, quite a number of bridges have been in service for 20 to 30 years, and concrete damage, spalling, steel bar corrosion, cracks, etc. On the other hand, due to the increase in traffic volume and vehicle load, the bearing capacity of some bridges is obviously insufficient and urgently needs to be reinforced, which has attracted the attention of the world. Since the 1960s, the protection problems of the stay cables have been continuously solved and improved, and the anti-corrosion problems of the external prestressing that belong to the same category as the stay cables have been well solved; A large number of steel bars are often arranged, and there are many curves. The crowded curves make the quality of grouting unable to be guaranteed, causing corrosion of the steel beams and affecting the durability of the structure. In the past 20 years, the general opinion in the world has tended to favor external prestressed steel. The structural durability of the harness is better than that of the inner harness.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the prior art, to provide a prestressed beam that is easy to replace, has small friction loss, light beam lifting weight, and is easy to assemble and construct. Continuous external prestressed continuous girder bridge.

The purpose of this utility model is achieved through the following technical solutions:

An externally prestressed continuous girder bridge that is simply supported first and then continuous, comprising a concrete beam, the concrete beam adopts an externally prestressed beam that is simply supported first and then continuous, and the two sides of the concrete beam are symmetrically installed with in vitro prestressed beams.

In the utility model, the concrete beam includes a wing plate, a web, a horseshoe and a diaphragm, and the wing plate, the web and the horseshoe are integrated and have a T-shaped cross section. The diaphragm, the diaphragm is provided with external prestressed channels, each span on both sides of the concrete beam is provided with a plurality of inter-span turning blocks, and the position of the middle pier top of each span of the concrete beam is The pier top steering block is provided, and the external prestressing beam is installed in the external prestressing channel of the diaphragm, the steering device of the inter-span steering block and the steering device of the pier top steering block, and the two ends of the external prestressing beam Anchor on the anchor block.

In the utility model, the inter-span steering block is arranged symmetrically at the position of the inner diaphragm of the second concrete beam, so that the external prestressed beam is bent upward from this position, and the pier top steering block is arranged at the end of the concrete beam position from which the external prestressing beam is bent downward.

In the utility model, the inter-span steering block and the pier top steering block are formed by enlarging and thickening the cross-sectional size of the standard diaphragm.

In the utility model, the concrete beam is a T-shaped cross-section beam.

Due to the adoption of the above scheme, the external prestressed structure arranges the prestressed tendons outside the main structure of the beam, and is connected to the beam body through the anchor blocks at both ends, the turning blocks between the spans, and the turning blocks at the top of the pier. The basic design idea is that in the construction stage , using the internal prestressed beams to a minimum to realize the stress of the overall structure in the construction stage, and then use the second-stage external prestressed beams to bear the second-stage dead load and service load.

Due to the adoption of the above scheme, it has the following significant advantages:

(1) The external prestressed beams are arranged outside the web, which is convenient for maintenance and replacement. At the same time, the self-weight of the beam is reduced, the spanning capacity of the bridge is increased, and the shortcomings of dense bellows and difficult vibration of the web are avoided. Light weight, easy to transport and install.

(2) The external prestressed beams are arranged in full length, which saves the negative moment beams and anchors at the top of the pier, and reduces the thickness of the pavement layer required for anchorage on the bridge deck.

(3) The direction of the external prestressed beam changes through the steering block between the spans and the top of the pier, and only contacts with the concrete at the steering block between the spans, the top of the pier and the anchorage, so that the friction loss of the prestress is reduced and the prestress is improved. benefit.

Description of drawings

Fig. 1 is the structural representation of the erection of the concrete T beam of the present invention and its external prestressed bundle, inter-span steering block, pier top steering block, and anchor block arrangement. the

Figure 2 is an enlarged view of Figure 1 A.

Fig. 3 is the utility model concrete T-beam structure schematic diagram.

Fig. 4 is the sectional view of the external prestressing beam of the utility model.

Fig. 5 is the sectional view of the utility model concrete T beam.

In the accompanying drawings 1-5: 1---anchor block, 2---span steering block, 3---external prestressed beam, 4---pier top steering block, 5---shock absorber, 6 ---Steering device, 7---Embedded pipe, 8---Anchor, 9---Epoxy coated steel strand, 10---Embedded steel plate, 11---PE casing, 12- --Grease, 13---external prestressing hole, 14---horseshoe, 15---wing plate, 16---diaphragm, 17---web.

Detailed ways

The specific implementation of the simply supported and then continuous externally prestressed continuous girder bridge will be described in detail below in conjunction with the accompanying drawings.

As shown in Figures 1, 2, 3, 4, and 5, a simply-supported and then continuous externally prestressed continuous girder bridge includes concrete beams, and the concrete beams are simple-supported and then continuous externally prestressed beams. The two sides of the concrete beam are symmetrically installed with external prestressed beams 3 which play a bearing role.

In the utility model, the concrete beam includes a wing plate 15, a web 17, a horseshoe 14 and a diaphragm 16, and the wing plate 15, the web 17 and the horseshoe 14 are integrated and have a T-shaped cross section. The concrete on the web 17 is provided with a plurality of said transverse diaphragms 16, said transverse diaphragms 16 are provided with external prestressed tunnels 13, and each span of said concrete beam is provided with a plurality of spans on both sides of the web. Steering block 2, the position of each intermediate pier top of the concrete beam is provided with a pier top steering block 4, and the external prestressed bundle 3 is installed on the external prestressed channel 13 of the diaphragm 16, and the steering block 2 between the spans In the steering device of the device 6 and the steering block 4 at the top of the pier, the two ends of the external prestressing beam 3 are anchored on the anchoring block 1 .

In the utility model, the inter-span steering block 2 is arranged symmetrically at the position of the inner diaphragm of the second concrete beam, so that the external prestressed beam 3 is bent upward from this position, and the pier top steering block 4 is arranged on the concrete beam. The beam end position is such that the external prestressing beam is bent downward from this position.

In the utility model, the inter-span turning block 2 and the pier top turning block 4 are formed by enlarging and thickening the cross-sectional size of the standard diaphragm.

In the utility model, the concrete beam is a T-shaped cross-section beam.

In the present utility model, the external prestressing bundle 3 includes epoxy sprayed steel strand 9, PE sleeve 11, grease 12, and the PE sleeve 11 is set outside the epoxy sprayed steel strand 9, and the Grease 12 is filled between the PE sleeve 11 and the epoxy-coated steel strand 9 .

In the utility model, the external prestressed beam 3 is provided with a vibration damping device 5 at intervals of 8-10 m, and the vibration damping device 5 is fixed on the concrete beam through a pre-embedded steel plate 10 .

The construction method of the utility model: after pouring the concrete T-beam, wait until the concrete strength reaches 95% of the design strength, stretch the internal prestressed bundle, and the internal prestressed bundle adopts low-relaxation prestressed steel strands; then install the permanent supports of each bridge pier Set up concrete T beams hole by hole, set inter-span turning blocks 2 between each span of concrete T beams, set pier top turning blocks 4 at the top of each middle pier of concrete T beams, and set wet joints 60cm at the ends of the beams; after erection After the concrete T beam, the external prestressed beam 3 passes through the embedded pipe 7 of the anchor block 1, the external prestressed channel hole 13 of the diaphragm 16, the steering device 6 of the steering block 2 between the spans, and the steering block 4 at the top of the pier, and then connects To the other concrete T beam, continuously form the external prestressed beams arranged in the whole length, and the two ends of the external prestressed beams 3 are fixed on the anchor block 1 through the anchor 8; the wet joint of the beam end at the top of the pouring pier makes the concrete T beam The structural continuity is formed in the longitudinal direction, and the cast-in-place wet joints between the flange and the diaphragm are horizontally connected to form a whole, and the external prestressed beams are stretched for the first time; after the construction of the bridge deck system (the construction of the bridge deck system includes: Pouring anti-collision railings or installing wave-shaped guardrails, pouring cement concrete and asphalt concrete on the bridge deck, installing drainage facilities, etc.), and stretching the external prestressed beams for the second time.

Example: As shown in Figure 1, it is a three-span concrete T-beam bridge, which adopts an externally prestressed continuous T-beam bridge that is simply supported and prefabricated first, and then the structure is continuous. (24m + 41m + 35m) girder bridge, the load class is automobile-super class 20, trailer-120, and the concrete T-beam is made of C50 concrete. As shown in Figure 5, in order to maintain coordination with the height of the front and rear beams and reduce the type of beam height, the beam height of the concrete T beam is 2.3 m, and the concrete T beam adopts a T-shaped section. The concrete T beam includes a wing plate 15, a web plate 17, The horseshoe 14, the diaphragm 16, the external prestressing beam 3 arranged outside the web 17, the steering device 6 and the anchor system, the external prestressing beam 3 is arranged outside the web 17, so that the beam rib width near the mid-span Reduced from the original 22cm to 18cm, the width of the horseshoe 14 was reduced from the original 54cm to 42cm; the external prestressed beams are arranged in 3 lengths, saving the negative moment beams and anchors at the top of the pier, and thinning the bridge deck due to anchoring needs As for the thickness of the pavement layer, the thickness of the pavement layer on the bridge deck is reduced from 15 cm to 10 cm. Transverse diaphragms are installed at the fulcrum and mid-span of the whole bridge, and the transverse slope of the bridge deck is formed by the combination of prefabricated concrete T-beam wing plates along the slope and oblique placement of cover beams.

Prestressing system: The bridge adopts the method of internal prestressing and external prestressing mixed reinforcement.

低松弛预应力钢绞线，其抗拉标准强度

，弹性模量，张拉控制应力，锚具8采用HVM群锚体系。The internal prestressing beam 3 adopts the nominal diameter

Low-relaxation prestressed steel strands, the standard tensile strength of which

,Elastic Modulus , tension control stress , Anchorage 8 adopts HVM group anchor system.

无粘结低松弛环氧喷涂钢绞线9，其抗拉标准强度

，弹性模量

。全桥采用2—6

体外预应力束3沿混凝土T梁腹板17两侧通长布置。体外预应力束3外套装高密度聚乙烯PE套管11，张拉体外预应力束3后在PE套管11内灌入油脂12，使用OVM锚具8，沿PE套管11每隔8~10m设置一道减振装置5，减震装置5通过预埋钢板10固定在混凝土T梁上。As shown in Figures 1 and 4, the external prestressing beam 3 adopts the nominal diameter

Unbonded low-relaxation epoxy sprayed steel strand 9, its standard tensile strength

,Elastic Modulus

. The whole bridge adopts 2-6

The external prestressed beams 3 are arranged along the entire length of both sides of the concrete T-beam web 17 . The external prestressing beam 3 is covered with a high-density polyethylene PE sleeve 11, and after the external prestressing beam 3 is stretched, grease 12 is poured into the PE sleeve 11, and the OVM anchor 8 is used to run along the PE sleeve 11 at intervals of 8~ A shock absorbing device 5 is installed at 10m, and the shock absorbing device 5 is fixed on the concrete T-beam through the embedded steel plate 10.

Steering and anchoring system:

The steering block is an important part for the external prestressed beam to maintain the designed bending shape within the span and transmit the cable force firmly. The joint is respectively provided with inter-span steering blocks and pier top steering blocks at the positions of each span and the middle pier top. According to the bending radius, bending angle and tension force of the external prestressed beam, the inter-span steering block is symmetrically arranged at the position of the second internal diaphragm of the concrete T beam, and the thickness of the inter-span steering block is set to 60 cm. The top turning block is set at the end of the concrete T beam, and the thickness of the turning block on the top of the pier is 75 cm. The structural layout is shown in Figure 1. The ANSYS software is used to analyze the local force of the inter-span steering block and the pier top steering block, and the distribution of tensile stress and shear stress generated when the external prestressed beam is turned is obtained. Based on this, the inter-span steering block and the pier top steering block Ring bars enclosing a single turning bar and closed hoops enclosing all bars in the block along the perimeter of the turning block between spans and the turning block at the top of the pier, and connecting the ring bars and stirrups with the longitudinal reinforcement in the beam Knot.

The utility model is not limited to the above-mentioned embodiment, but can be extended to a multi-span externally prestressed continuous girder bridge that is simply supported first and then continuous. Within the protection scope of the present utility model.

Claims (7)

1. a kind of externally prestressed continuous girder bridge that is simply supported first and then continuous, comprising concrete beams, is characterized in that: said concrete beams adopt first simply supported and then continuous externally prestressed beams, and both sides of said concrete beams are installed symmetrically There are external prestressed beams (3) that play a load-bearing role. 2. The externally prestressed continuous girder bridge simply supported first and then continuous according to claim 1, characterized in that: the concrete girder includes wing plates (15), webs (17), horseshoes (14) and diaphragms The plate (16), the wing plate (15), the web (17) and the horseshoe (14) are integrated and have a T-shaped cross section, and a plurality of the diaphragms (16) are arranged on the concrete beam , the diaphragm (16) is provided with external prestressed tunnels (13), each span on both sides of the concrete beam is provided with a plurality of inter-span steering blocks (2), and each span of the concrete beam The top of the middle pier is provided with a turning block (4) on the top of the pier, and the external prestressing beam (3) is installed on the external prestressing channel (13) of the diaphragm (16) and the steering device of the interspan steering block (2). (6) and the steering block (4) at the top of the pier, the two ends of the external prestressed beam (3) are anchored on the anchor block (1). 3. The externally prestressed continuous girder bridge simply supported first and then continuous according to claim 2, characterized in that: the inter-span steering block (2) is symmetrically arranged at the position of the diaphragm in the second road of the concrete beam, so that the The external prestressed beam (3) is bent upward from this position, and the pier top turning block (4) is arranged at the beam end of the concrete beam, so that the external prestressed beam is bent downward from this position. 4. The externally prestressed continuous girder bridge simply supported first and then continuous according to claim 2 or 3, characterized in that: the inter-span steering block (2) and the pier top steering block (4) are made of standard diaphragms Increase and thicken the section size. 5. The externally prestressed continuous girder bridge simply supported first and then continuous according to claim 1 or 2, characterized in that: the concrete girder is a T-shaped cross-section girder. 6. The externally prestressed continuous girder bridge simply supported first and then continuous according to claim 1 or 2, characterized in that: the externally prestressed bundles (3) include epoxy sprayed steel strands (9), PE sleeves tube (11), grease (12), the PE sleeve (11) is set outside the epoxy sprayed steel strand (9), the PE sleeve (11) and the epoxy sprayed steel strand Grease (12) is filled between (9). 7. The externally prestressed continuous girder bridge simply supported first and then continuous according to claim 1 or 2, characterized in that: the externally prestressed bundle (3) is provided with damping devices (5) every 8-10m ), the damping device (5) is fixed on the concrete beam by the embedded steel plate (10).

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