CN111549658A - Continuous bridge joint structure and continuous box girder bridge structure - Google Patents

Abstract

The invention relates to a continuous bridge joint structure and a continuous box girder bridge, comprising two prefabricated box girders and ultrahigh-performance concrete poured at the joint between the two prefabricated box girders; the method is characterized in that the top plates of two prefabricated box girders are connected at a continuous pier through cast-in-place ultrahigh-performance concrete to change a bridge structure from a simple support to a partial structure continuous state; the continuous box girder bridge structure adopts the continuous bridge joint structure. Compared with the prior art, the bridge pier top joint with the simple support-to-continuous structure is optimally designed, the joint only needs to be connected with the top plate, the complex process of jacking and dismantling after a temporary support is arranged is omitted, the construction difficulty is greatly reduced, the concrete volume poured in the construction site is reduced, and the construction efficiency of the joint and the economical efficiency of bridge construction are improved.

Description

A continuous bridge joint structure and continuous box girder bridge structure

technical field

The invention relates to the technical field of bridge engineering, in particular to a continuous bridge joint structure and a continuous box girder bridge structure.

Background technique

The conventional simply supported continuous structural system bridge involves system conversion during construction. The continuous pier tops should be set up with temporary supports first. After the bridge is transformed into a continuous structural system, the temporary supports are removed and replaced by permanent supports. In addition, cast-in-place ordinary concrete is usually used for the joints at the top of the continuous pier, which requires a large amount of pouring and welding of steel bars on site. The construction process is cumbersome and the construction period is long.

In order to improve the joint performance and construction efficiency, ultra-high performance concrete (UHPC) has been applied to bridge joints, but the unit price of UHPC is currently relatively high. The full-section pouring at the joints requires a large amount of squares, and the cost is high.

Chinese patent CN108316132A discloses a simply supported variable continuous bridge structure. A section of prefabricated beams are respectively arranged on both sides of the continuous pier top, and the beam end faces of the prefabricated beams on both sides are provided with spacing. For the continuous pier top of the structure, only the top and bottom plates of the two sections of prefabricated beams are connected, and the abdominal part of the beam body is not connected, forming a transition from a simply supported state to a continuous state. The patented technology is a small box girder bridge with multiple transverse main beams with small span. The proportion of live load bending moment is relatively high. Only the bending resistance of the top plate cannot meet the force requirements. The compression creates a moment to resist the negative bending moment of the fulcrum, so it is necessary to connect the top and bottom plates of the prefabricated beam to meet the force requirements. In addition, the connection structure of the patented technology is a plate-like structure, the connection strength at the joint is relatively weak, and the construction is relatively complicated.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a continuous bridge joint structure and a continuous box girder bridge structure in order to overcome the defects of large concrete pouring volume, high construction difficulty and low construction efficiency in the prior art. The present invention provides a continuous bridge joint structure with a partial structure of cast-in-place ultra-high performance concrete. Through the use of UHPC, under the premise of ensuring the mechanical performance of the joint, the bridge pier top of the traditional simply supported variable continuous structure can be improved to the greatest extent. The joints are optimally designed to simplify construction and improve construction efficiency and economy. The present invention also provides a continuous box girder bridge with a partial structure obtained by utilizing the joint structure.

The object of the present invention can be realized through the following technical solutions:

A continuous bridge joint structure, comprising two prefabricated box girders and ultra-high performance concrete poured at the joint between the two prefabricated box girders; The roof is connected by cast-in-place ultra-high-performance concrete to realize the bridge structure from simply supported to partially structurally continuous state.

In a simply supported continuous bridge, when the span increases, the proportion of the structural self-weight to the design load increases significantly, the proportion of the second-phase dead load and live load is relatively low, and the pier top joints basically only bear the second-phase dead load , the negative bending moment that may be generated by the vehicle live load and other loads; based on this analysis, the present invention optimizes the design of the pier top joint of the simply supported variable continuous bridge, thereby simplifying the construction and improving the construction efficiency and economy.

Compared with the prior art, the present invention is mainly suitable for the whole-hole large box girder with a span of more than 50m. Its structure self-weight accounts for a high proportion of the total load, and the live load bending moment of the pier top is relatively small, which can be borne by the local structural connection of the top plate. In this part of the negative bending moment, the cast-in-place concrete has less square volume, and the construction is fast; the joint of the present invention is a T-shaped structure, and the cast-in-place UHPC joint and the prefabricated beam section are increased by setting the L-shaped notch on the top plate of the prefabricated box girder. The contact surface of the beam section makes the transition of the internal force of the beam section smooth, improves the connection strength, and further reduces the amount of concrete cast in place while ensuring the structural performance.

Further, a slot is provided at the junction of the end face and the upper surface of the top plate of the prefabricated box girder, and the slot of the two prefabricated box girder and the end face of the top plate form a pouring space for pouring ultra-high performance concrete.

Further, the slot is L-shaped, and the pouring space is a T-shaped structure.

Further, the distance between the end faces of the top plates of the two prefabricated box beams is 30-90 cm.

Further, along the longitudinal direction of the continuous bridge, the width of the pouring space is 2 to 4 times, preferably 3 times, the distance between the end faces of the top plates of the two prefabricated box girders.

Further, the end of the top plate of the prefabricated box girder is a plate-like structure with uniform thickness, and the height of the pouring space is the same as the thickness of the plate-like structure of the end of the top plate, and is in the transverse direction of the continuous bridge. The height of the pouring space remains unchanged.

Further, the height of the notch of the top plate is one quarter to one third of the height of the pouring space, and is not less than 20 cm.

Further, the prefabricated box girder is a prefabricated whole-hole box girder.

The construction method of the above-mentioned continuous bridge joint structure comprises the following steps:

(S-1) Prefabricated whole-hole box girder at the factory;

(S-2) Transport the prefabricated box girder to the bridge site, place two rows of permanent supports on the top of the continuous pier in the longitudinal direction of the bridge, and hoist the prefabricated whole-hole box girder on the corresponding supports to form a simply supported state and put it in place. Then install the formwork of the cast-in-place UHPC joint between the notch and the end face of the top plate of the prefabricated box girder;

(S-3) After binding the steel bars at the joints and installing the prestressed pipes on the roof and the steel beams, pour the mixed UHPC into the joint formwork;

(S-4) UHPC maintenance, after the joint UHPC reaches the strength, the formwork is removed and the roof prestressed beam is stretched, and the construction is completed.

The present invention also provides a continuous box girder bridge structure using the above-mentioned continuous bridge joint structure.

Further, two rows of permanent supports are arranged on the top of the continuous pier along the longitudinal direction of the continuous bridge, and the prefabricated box girder is supported by the permanent supports in a simply supported state.

Further, both ends of the prefabricated box girder are provided with end beams.

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

(1) The present invention simplifies the pier top joint structure of the traditional simply supported continuous bridge by using ultra-high performance concrete (UHPC) and utilizes its excellent mechanical properties, eliminating the need for setting temporary supports and then lifting and dismantling them. The cumbersome process, on the basis of simply supported beams, only the roof is connected to form a partial structural continuous bridge, which not only retains the advantages of traditional simply supported continuous bridges, but also has a simple structure, which greatly reduces the difficulty of construction;

(2) Only the top plate needs to be connected at the joint, the amount of concrete poured on the construction site is greatly reduced, and because of the good anchorage performance of UHPC and steel bars, the steel bar arrangement can be simplified, so the economy is better;

(3) The notch set at the top plate of the prefabricated whole-hole box girder increases the contact surface between the UHPC and the prefabricated beam section, improves the connection strength, and is conducive to the stress at the joint;

(4) Because UHPC has the characteristics of early strength, the prestressing can be stretched 1 to 5 days after pouring, which can greatly improve the joint construction efficiency.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is a sectional view of the present invention;

Fig. 3 is the sectional view of middle A-A of Fig. 2;

Fig. 4 is a sectional view at B-B in Fig. 2;

Figure 5 is a sectional view at C-C in Figure 2;

Figure 6 is a sectional view at D-D in Figure 2;

In the figure, 1 is the precast box girder, 2 is the slot, 3 is the ultra-high performance concrete, 4 is the center line of the bearing, 5 is the manhole, 6 is the permanent bearing, h1 is the height of the pouring space, and h2 is the height of the slot. Height, L1 is the distance between the top plate end faces of the two prefabricated box girders, and L2 is the width of the pouring space.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

Example 1

A continuous bridge joint structure, which is a partially structural continuous bridge joint structure using cast-in-place ultra-high performance concrete, as shown in Figure 1, includes two prefabricated whole-hole box girder 1 and two prefabricated box girders. For the ultra-high performance concrete 3 at the joint between the beams 1, at the continuous pier, two prefabricated box girders 1 are arranged at intervals, and the ultra-high performance concrete 3 is cast in-situ between the top plates of the prefabricated box girder 1, that is, in the continuous pier. Only the top plates of the two prefabricated box girders 1 are connected at the pier, so that the bridge structure is changed from simply supported to partially continuous state. The mid-beam body and the bottom plate, and the bottom plate of the two prefabricated box beams 1 are provided with a spacer. What needs to be specified here is that ultra-high performance concrete (UHPC) has excellent mechanical properties, and has a high bond strength with the interface of ordinary concrete, and the anchoring performance with steel bars is also better than that of ordinary concrete. Therefore, using it in the joint structure of continuous pier top can optimize the joint design to the greatest extent. On the basis of simply supported beams, only the roof is connected to form a part of the continuous bridge structure, which simplifies the construction steps and greatly reduces the amount of concrete cast in place, thereby Reduce construction difficulty and improve construction efficiency.

As shown in Figures 1 and 2, a notch 2 is provided at the junction between the end face and the upper surface of the top plate of the prefabricated box girder 1, and the structure of the notch is L-shaped. The pouring space for pouring ultra-high performance concrete, in this embodiment, the pouring space is a T-shaped structure. The setting of the slot 2 increases the contact surface between the UHPC and the prefabricated beam section, which can smooth the internal force of the transition beam section, improve the connection strength, and facilitate the stress at the joint. In this embodiment, the distance L1 between the top plate end faces of the two prefabricated box girders is 60cm; along the longitudinal direction of the continuous bridge, the width L2 of the pouring space is 2 times the distance L1 between the top plate end faces of the two prefabricated box girders times.

Combining with Figure 1, Figure 2, Figure 3 and Figure 4, it can be seen that the end of the top plate of the prefabricated box girder 1 is a plate-like structure with uniform thickness, and the height h1 of the pouring space is related to the plate-like structure of the end of the top plate. The thickness is the same, and the height h1 of the pouring space remains unchanged in the transverse direction of the continuous bridge; in this embodiment, the height h2 of the notch of the top plate is one third of the height h1 of the pouring space, and is not less than 20cm. As shown in FIG. 5 , the slot 2 is arranged along the width direction of the prefabricated box girder, and is a through slot.

In this embodiment, the prefabricated box girder is a prefabricated whole-hole large box girder, and a manhole 5 is provided near the end of the prefabricated box girder 1 .

The construction method of the above-mentioned continuous bridge joint structure comprises the following steps:

(S-1) Prefabricated whole-hole large box girder at the factory and stored for 3 months;

(S-2) Transport the prefabricated beam sections to the bridge site, place two rows of permanent supports 6 on the top of the continuous pier in the longitudinal bridge direction, and hoist the prefabricated whole-hole box girder in each hole on the corresponding support 6, and prefabricate the whole hole The centerline 4 of the support of the box girder is shown in Figure 1, forming a simply supported state. After being in place, a formwork for the joint of cast-in-place ultra-high performance concrete (UHPC) is installed between the notch and the end face of the top plate of the prefabricated box girder;

(S-3) After binding the steel bars at the joints and installing the roof prestressed pipes and steel beams, pour the mixed ultra-high performance concrete (UHPC) into the joint formwork;

(S-4) Ultra-high-performance concrete (UHPC) curing, after the joint ultra-high-performance concrete (UHPC) reaches the strength, the formwork is removed and the roof prestressing beam is stretched, and the construction is completed.

The construction process of the joint structure is simple, and the technical scheme of the present invention simplifies the pier top joint structure of the traditional simply supported continuous bridge, greatly reduces the construction difficulty, and improves the construction efficiency and economy.

The above-mentioned continuous bridge joint structure is optimized for the traditional simply supported variable continuous structure bridge pier top joint. The joint only needs to connect the top plate, and the tedious process of setting temporary supports and then lifting and dismantling is omitted, which greatly reduces the It reduces the difficulty of construction and reduces the amount of concrete poured at the construction site, thereby improving the construction efficiency of joints and the economy of bridge construction.

In the continuous box girder bridge structure using the above continuous bridge joint structure, as shown in Figure 6, two rows of permanent supports 6 are arranged on the top of the continuous pier along the longitudinal direction of the continuous bridge. The seat is the permanent support 6, and the prefabricated box girder 1 is designed as a simply supported beam, with end beams at both ends.

Example 2

A continuous bridge joint structure is a continuous bridge joint structure with a partial structure of cast-in-place ultra-high performance concrete, as shown in Figure 1, comprising two prefabricated box girders 1 and two prefabricated box girders 1 The ultra-high performance concrete 3 at the joint between the two prefabricated box girders 1 is arranged at intervals at the continuous pier. Only the top plates of the two prefabricated box girders 1 are connected, so that the bridge structure is changed from simply supported to partially structurally continuous state. As shown in Figures 1 and 2, a slot 2 is provided at the junction between the end face and the upper surface of the top plate of the prefabricated box girder 1, and the slot 2 of the two prefabricated box girder 1 and the end face of the top plate form a pouring space for pouring ultra-high performance concrete , in this embodiment, the pouring space is a T-shaped structure. The setting of the slot 2 increases the contact surface between the UHPC and the prefabricated beam section, which can smooth the internal force of the transition beam section, improve the connection strength, and facilitate the stress at the joint. In this embodiment, the distance L1 between the top plate end faces of the two prefabricated box girders is 30cm; along the longitudinal direction of the continuous bridge, the width L2 of the pouring space is 4 times the distance L1 between the top plate end faces of the two prefabricated box girders times.

Combining with Figure 1, Figure 2, Figure 3 and Figure 4, it can be seen that the end of the top plate of the prefabricated box girder 1 is a plate-like structure with uniform thickness, and the height h1 of the pouring space is related to the plate-like structure of the end of the top plate. The thickness is the same, and the height h1 of the pouring space remains unchanged in the transverse direction of the continuous bridge; in this embodiment, the height h2 of the notch of the top plate is one third of the height h1 of the pouring space, and is not less than 20cm.

Example 3

A continuous bridge joint structure is a continuous bridge joint structure with a partial structure of cast-in-place ultra-high performance concrete, as shown in Figure 1, comprising two prefabricated box girders 1 and two prefabricated box girders 1 The ultra-high performance concrete 3 at the joint between the two prefabricated box girders 1 is arranged at intervals at the continuous pier. Only the top plates of the two prefabricated box girders 1 are connected, so that the bridge structure is changed from simply supported to partially structurally continuous state. As shown in Figures 1 and 2, a slot 2 is provided at the junction between the end face and the upper surface of the top plate of the prefabricated box girder 1, and the slot 2 of the two prefabricated box girder 1 and the end face of the top plate form a pouring space for pouring ultra-high performance concrete , in this embodiment, the pouring space is a T-shaped structure. The setting of the slot 2 increases the contact surface between the UHPC and the prefabricated beam section, which can smooth the internal force of the transition beam section, improve the connection strength, and facilitate the stress at the joint. In this embodiment, the distance L1 between the top plate end faces of the two prefabricated box girders is 90cm; along the longitudinal direction of the continuous bridge, the width L2 of the pouring space is 4 times the distance L1 between the top plate end faces of the two prefabricated box girders times.

Combining with Figure 1, Figure 2, Figure 3 and Figure 4, it can be seen that the end of the top plate of the prefabricated box girder 1 is a plate-like structure with uniform thickness, and the height h1 of the pouring space is related to the plate-like structure of the end of the top plate. The thickness is the same, and the height h1 of the pouring space remains unchanged in the transverse direction of the continuous bridge; in this embodiment, the height h2 of the notch of the top plate is a quarter of the height h1 of the pouring space, and is not less than 20cm.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various variations or modifications within the scope of the claims, which do not affect the essential content of the present invention.

Claims (10)

1. A continuous bridge joint structure comprises two prefabricated box girders (1) and ultrahigh-performance concrete (3) poured at a joint between the two prefabricated box girders (1); the method is characterized in that the top plates of two prefabricated box girders (1) are connected through cast-in-place ultrahigh-performance concrete (3) at the continuous piers to realize that the bridge structure is changed from a simple support to a partial structure continuous state.

2. A continuous bridge joint structure according to claim 1, characterized in that the intersection of the end face and the upper surface of the top plate of the prefabricated box girder (1) is provided with a notch (2), and the notches (2) of the two prefabricated box girders (1) and the end face of the top plate form a casting space for casting the ultra-high performance concrete (3).

3. The continuous bridge joint construction of claim 2, wherein the notch is L-shaped and the casting space is T-shaped.

4. A continuous bridge joint construction according to claim 2, wherein the distance (L1) between the end faces of the top plates of two prefabricated box girders is 30-90 cm.

5. A continuous bridge joint construction according to claim 2, characterized in that the width (L2) of the casting space is 2-4 times, preferably 3 times, the distance (L1) between the end faces of the top plates of two precast box girders in the longitudinal direction of the continuous bridge.

6. A continuous bridge joint construction according to claim 2, characterized in that the end of the top plate of the precast box girder (1) is a plate-like structure of uniform thickness, the height (h1) of the casting space is the same as the thickness of the plate-like structure of the end of the top plate, and the height (h1) of the casting space is kept constant in the transverse direction of the continuous bridge.

7. A continuous bridge joint construction according to claim 1, characterized in that the height (h2) of the notch of the roof slab is one quarter to one third of the height (h1) of the casting space and is not less than 20 cm.

8. A continuous box girder bridge structure constructed using the continuous bridge joint of claim 1.

9. A continuous box girder bridge construction according to claim 8, characterized in that the tops of the continuous piers are provided with two rows of permanent bearings (6) in the longitudinal direction of the continuous bridge, and the precast box girders (1) are supported with the permanent bearings (6) in a simply supported state.

10. A continuous box girder bridge construction according to claim 8, characterized in that the precast box girders (1) are provided with end cross beams at both ends.

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