Steel box girder and concrete pier column fixed structure

Abstract

The utility model relates to bridge engineering technical field, and disclose a kind of steel box girder and concrete pier column consolidation structure, including steel box girder, concrete pier column, shear nail and the adjusting member for adjusting the elevation of steel box girder installation, concrete pier column top is reserved with shear key, steel box girder bottom is equipped with for with concrete pier column top socket joint connection's notched, concrete pier column top outer circumferential wall is equipped with the slope of being inserted easily, concrete pier column top is inserted in the inside of notched, adjusting member includes jacking corbel and jack, jacking corbel is connected by bolt with the reserved planting bar on the outer wall below concrete pier column, jack is installed in jacking corbel top, jack top and steel box girder bottom are abutted. The present application is simple in structure, high in precision of factory prefabrication, force transmission is direct in socket design, stress concentration is small, and the elevation of section member is accurately adjusted, convenient for construction, applicable to complex environment and large-span bridge.

Description

Technical Field

[0001] This utility model relates to the field of bridge engineering technology, specifically to a steel box girder and concrete pier structure. Background Technology

[0002] Steel box girders are a common type of bridge structure. They primarily use box-shaped sections welded from steel plates or structural steel as load-bearing components, characterized by high strength, high stiffness, and good overall integrity, and are widely used in modern bridge engineering. The rigid connection between the steel box girder and the concrete pier is a common connection method in bridge engineering. This refers to the use of specific structures to rigidly connect the main beam of the steel box girder to the concrete pier, allowing both to share the load.

[0003] The current main method for consolidating steel box girders with piers involves installing steel sleeves within a certain range at the top of the pier. These sleeves are connected to the pier via shear keys or shear studs, and the top of the sleeves is welded to the top plate of the steel box girder. Stiffening ribs are also installed at the connection between the sleeves and the bottom of the box girder. In addition to this, some engineering applications also employ methods such as extending the pier reinforcement into the main girder, adding steel sections or bolts to the main girder at the top of the pier, and then pouring concrete inside the box girder. Existing steel box girder pier-girder consolidation techniques place high demands on the sleeve welds, requiring on-site welding. On-site welding quality control is difficult, and stress concentration occurs at the weld joints, leading to uneven stress distribution on the steel box girder. Accurate calculations are challenging, and reliability and durability need improvement.

[0004] An existing application with application number 202322090609.X discloses a pier-beam reinforcement structure for a steel box girder and a concrete pier, comprising a steel box girder, a concrete pier column, and a steel sleeve. The steel sleeve is arranged at the top of the concrete pier column. An inner cavity formed by crossbeams is provided within the steel box girder. The steel sleeve includes a main section located between the bottom plate of the steel box girder and the concrete pier column, and a torsional section located above the main section and inserted into the inner cavity. Both the interior of the steel sleeve and the inner cavity are filled with micro-expansion concrete. The steel box girder and the concrete pier column are connected by the steel sleeve, and the torsional section of the steel sleeve is inserted into the inner cavity of the steel box girder. The torsional section of the steel sleeve is reliably connected to the steel box girder by micro-expansion concrete and shear studs.

[0005] The aforementioned steel box girder and concrete pier consolidation structure involves a steel sleeve divided into a main section and a torsional section. The steel box girder has an internal cavity formed by crossbeams, resulting in a complex structure with stringent installation precision requirements, cumbersome procedures, and a large amount of on-site work. When the steel sleeve, micro-expansion concrete, and shear studs work together under load, the stress distribution is complex, making accurate calculations difficult. Furthermore, stress concentrations easily occur at welds and component connections, affecting structural durability. Extensive on-site welding (such as stiffening rib fillet welds) makes quality control difficult, and welds are prone to becoming sources of defects. Simultaneously, the steel sleeve works in conjunction with multiple components, and durability is affected by various structural nodes, resulting in numerous risk points. This structure fails to meet the project's requirements for ease of construction, rational stress distribution, and durability. Therefore, to address these shortcomings, we propose a steel box girder and concrete pier consolidation structure. Utility Model Content

[0006] The purpose of this utility model is to provide a steel box girder and concrete pier consolidation structure to solve the problems mentioned in the background art, which currently require on-site welding for the consolidation of steel box girders and concrete piers. On-site welding quality control is difficult, stress concentration occurs at the weld joint, and the steel box girder is subjected to uneven stress.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A steel box girder and concrete pier structure includes a steel box girder, a concrete pier, shear studs, and an adjusting component for adjusting the installation elevation of the steel box girder. The top of the concrete pier has a shear key, and the bottom of the steel box girder has a slot for insertion into the top of the concrete pier. The outer circumferential wall of the top of the concrete pier has a ramp for easy insertion, and the top of the concrete pier is inserted into the slot.

[0009] Preferably, the adjusting component includes a lifting bracket and a jack. The lifting bracket is connected to a pre-installed rebar located on the outer wall below the concrete pier by bolts. The jack is installed on the top of the lifting bracket, and the top of the jack abuts against the bottom of the steel box girder. The lifting bracket and the jack are detachable.

[0010] Preferably, the shear studs are evenly distributed on the inner circumferential wall of the slot outside the slope, and the shear studs are connected to the inner circumferential wall of the slot of the steel box girder by welding.

[0011] Preferably, the groove is 1-2m deep, and the concrete pier inside the groove is uniformly filled with high-strength grouting concrete.

[0012] Preferably, reinforcing ribs are distributed on the steel box girder on both sides of the slot, and the reinforcing ribs are connected to the transverse diaphragm at the support point of the box girder.

[0013] Preferably, the outer surface of the concrete pier located inside the groove is provided with a roughened layer.

[0014] This utility model has the following beneficial effects:

[0015] 1. This application pre-reserves the socket in the steel box girder processing plant. Compared with the latter's complex structure such as steel sleeve and inner cavity, the structure is simpler, the degree of factory prefabrication is high, which is conducive to quality control, the operation is simple, and the consolidation can be completed by grouting the joint material, with fewer construction steps.

[0016] 2. The groove depth is 1-2m. Combined with the caulking material, the force is transferred directly and evenly, which can reduce stress concentration. The groove is pre-reserved in the factory, making the quality easy to control. After the caulking material is poured, it forms a whole. The durability is less affected by on-site welding, effectively improving the reliability of the pier-beam consolidation, avoiding on-site weld quality problems, and optimizing the stress concentration problem of the box girder bottom plate.

[0017] 3. The steel box girder adopts a socket-type structure, using the lifting brackets and jacks at the bottom of the beam to adjust the elevation and temporarily fix it. The installation elevation of the steel box girder can be adjusted on site, which solves the problem of pier top elevation error and improves construction accuracy. Attached Figure Description

[0018] Figure 1 This is an overall side view of the present invention.

[0019] Figure 2 This is a schematic diagram of the side structure of the steel box girder and concrete pier column of this utility model.

[0020] Figure 3 This is a top view of the present invention.

[0021] Figure 4 This is a schematic diagram of the disassembled structure of the steel box girder and concrete pier column of this utility model.

[0022] In the diagram: 1. Steel box girder; 11. Groove; 12. Reinforcing rib; 2. Concrete pier; 21. Shear key; 22. Slope; 23. Roughened treatment layer; 3. Adjusting component; 31. Lifting bracket; 33. Jack; 4. Shear stud. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Please see the appendix Figure 1, Figure 2 , Figure 3 and Figure 4As shown, a steel box girder and concrete pier structure includes a steel box girder 1, a concrete pier 2, shear studs 4, and an adjusting member 3 for adjusting the installation elevation of the steel box girder 1. A shear key 21 is pre-installed at the top of the concrete pier 2. When the steel box girder 1 and the concrete pier 2 are connected via a socket joint 11, significant horizontal and vertical shear forces exist at the interface. The shear key 21, as a pre-installed protrusion at the top of the concrete pier 2, can be directly embedded into the socket joint 11 of the steel box girder. Through mechanical interlocking, the shear force borne by the pier is transferred to the steel box girder, preventing interface slippage and ensuring that the two form an integral load-bearing system. The convex and concave structure of the shear key 21 can... Effectively resisting the relative misalignment between the steel box girder 1 and the pier, especially under horizontal forces such as vehicle loads and wind, it can prevent shear failure of the steel box girder along the top of the pier. The bottom of the steel box girder 1 has a slot 11 for insertion into the top of the concrete pier 2. The outer circumferential wall of the top of the concrete pier 2 has a ramp 22 for easy insertion. The top of the concrete pier 2 is inserted into the slot 11, with the ramp 22 serving as a transition. The ramp 22 has a chamfer angle of 15°-30° to guide the top of the concrete pier 2 into the slot 11 and avoid stress concentration. Shear studs 4 are evenly distributed on the inner circumferential wall of the slot 11 outside the ramp 22. 4. Shear studs 4 are welded to the inner circumferential wall of the slot 11 of the steel box girder 1. Their rods are embedded in the high-strength concrete grout. Through the combined action of shear resistance and concrete bearing capacity, the loads (such as bending moment, shear force, and torque) borne by the steel box girder are transferred to the grout and concrete pier 2. When the steel box girder 1 is subjected to horizontal force, the shear stud 4 directly resists the relative slippage between the steel and concrete. (Calculated based on a standard shear stud with a diameter of 19mm and a length of 100mm). Actual test data shows that a single shear stud can withstand a shear force of 50-80kN. In the vertical direction, the shear stud 4 can inhibit the movement of the steel box girder 1 and the grout. The concrete separation tendency avoids force transmission failure caused by interface peeling. Compared with the defects of traditional steel hoop schemes that rely on weld force transmission (such as stress concentration and difficulty in controlling welding quality), shear studs 4, through the characteristics of distributed arrangement and flexible force transmission, transform concentrated stress into distributed load, avoiding structural damage caused by single weld failure. Reinforcing ribs 12 are distributed on the steel box beams 1 on both sides of the slot 11. The reinforcing ribs 12 penetrate and connect to the transverse diaphragm of the box beam in the middle support on the steel box beam 1. The outer surface of the concrete pier column 2 located inside the slot 11 is provided with a roughening treatment layer 23, with a roughening depth ≥5mm, evenly distributed in a quincunx pattern, and the surface roughness index after roughening is ≥0.The surface of the 5mm thick concrete pier needs to be rinsed with a high-pressure water gun after roughening to ensure the cleanliness of the interface before pouring the high-strength caulking concrete. This enhances the adhesion between the caulking concrete and the pier. The groove 11 is 1-2m deep. The concrete pier 2 inside the groove 11 is uniformly filled with high-strength caulking concrete. After the main beam is installed, high-strength and tough caulking material is poured into the socket 11 to form a connection. The groove 11 is pre-reserved in the steel box girder 1 processing plant to reduce on-site welding and avoid the on-site assembly of traditional steel sleeves and the problem of quality control of a large number of welds. Before pouring, the elevation of the steel box girder 1 can be precisely adjusted by adjusting the adjusting piece 3. The fluidity of the caulking concrete can fill tiny gaps, solve the construction error at the top of the pier, and has strong adaptability. The caulking concrete completely encapsulates the contact area between the steel box girder's slot 11 and the pier, isolating it from external moisture and corrosive media, thus preventing steel corrosion. Compared to traditional welds, the concrete protective layer offers superior durability. The concrete and steel components form a rigid connection through shear studs 4 and a roughened surface. Creep and shrinkage effects under long-term loads are mitigated by the material's toughness, reducing the risk of joint fatigue damage, decreasing on-site welding equipment investment and high-altitude work, and lowering labor costs. High-strength concrete is cheaper per unit than special welding materials, resulting in a more cost-effective overall construction. It is suitable for complex environments such as those spanning the sea and mountains, and is particularly suitable for large-span steel box girder bridges requiring high construction precision, avoiding the welding quality risks associated with traditional methods in harsh weather conditions.

[0025] Please see the appendix Figure 1 and Figure 4 As shown, the adjusting component 3 includes a lifting bracket 31 and a jack 33. The lifting bracket 31 is connected to the reserved rebar on the outer wall below the concrete pier 2 by bolts. The bolt type is ≥M20 and the rebar depth is ≥15d (d is the diameter of the rebar). The pull-out force of the bracket is ≥500kN. It is made of Q355B steel and welded. The bottom plate of the bracket is ≥300mm×300mm and the web thickness is ≥16mm. A horizontal steel plate (surface roughness Ra≤12.5μm) is set on the top for installing the jack. The jack (33) is installed on the top of the lifting bracket 31. The top of the jack 33 abuts against the bottom of the steel box girder 1. The jack 33 is a hydraulic jack with a rated lifting force ≥2000kN, a stroke ≥100mm, a lifting accuracy ≤0.5mm, and a pressure locking function (pressure holding time ≥24h). The lifting bracket 31 and the jack 33 are detachable.

[0026] The steel box girder 1 and the concrete pier 2 adopt a socket-type structure. The elevation is adjusted and temporarily fixed by using the lifting bracket 31 and the bottom jack 33. The installation elevation of the steel box girder 1 can be adjusted on site to solve the elevation error of the pier top and improve the construction accuracy. After the jacking is in place, the jack 33 locks the pressure and bears the self-weight of the steel box girder 1 until the strength of the caulking concrete reaches 80% of the design value (usually 7 days). After the caulking is completed, the jack 33 is unloaded and the bracket is removed. The bolt holes of the bracket are sealed with micro-expansion mortar, which does not affect the appearance and durability of the pier. The flexible support of the jack 33 can alleviate the instantaneous impact under the action of earthquake and avoid the stress change of traditional rigid support.

[0027] In the steel box girder 1 processing plant, the groove 11 and shear studs 4 are welded, and reinforcing ribs 12 are welded to both sides of the groove 11. During the construction of the concrete pier 2, shear keys 21 are pre-embedded, and a 15°-30° slope 22 is poured on top. The outer surface of the pier is roughened, and the lifting bracket 31 is processed according to the design dimensions and equipped with M20 bolts. The performance of the hydraulic jack 33 is checked. The rebar installation positions are marked on the outer wall below the concrete pier 2, holes are drilled and rebars are inserted, and the bottom plate of the lifting bracket 31 is connected to the rebars with M20 bolts. The steel box girder 1 is lifted by a crane to the top of the pier, so that the top of the pier is inserted into the groove 11 along the slope 22, completing the initial installation. First, position the hydraulic jack 33 on top of the lifting bracket 31, with a 20mm thick steel pad on the piston end to abut against the bottom plate of the steel box girder. Start the jacks in stages, monitor the elevation of the steel box girder with a level, and simultaneously adjust the synchronization of the jacks on multiple piers. After the elevation is adjusted to the correct position, lock the jack pressure valve and pour C60 grade high-strength joint-sealing concrete from the bottom of slot 11 upwards. After compaction, cover and cure. When the joint-sealing concrete reaches 80% of the design value (about 7 days), slowly unload the jacks, remove the bracket and bolts, seal the bolt holes of the bracket with micro-expansion mortar, smooth the surface, and apply an anti-corrosion coating. Construction is complete.

[0028] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A steel box girder and concrete pier structure, comprising a steel box girder (1), a concrete pier (2), shear studs (4), and an adjusting member (3) for adjusting the installation elevation of the steel box girder (1), characterized in that: The top of the concrete pier (2) is reserved with a shear key (21), and the bottom of the steel box girder (1) is provided with a slot (11) for insertion and connection with the top of the concrete pier (2). The outer circumferential wall of the top of the concrete pier (2) is provided with a ramp (22) for easy insertion, and the top of the concrete pier (2) is inserted into the slot (11).

2. The steel box girder and concrete pier fixed structure according to claim 1, characterized in that: The adjusting component (3) includes a lifting bracket (31) and a jack (33). The lifting bracket (31) is connected to the reserved reinforcing bars located on the outer wall below the concrete pier (2) by bolts. The jack (33) is installed on the top of the lifting bracket (31). The top of the jack (33) abuts against the bottom of the steel box girder (1). The lifting bracket (31) and the jack (33) are detachable.

3. The steel box girder and concrete pier fixed structure according to claim 1, characterized in that: The shear studs (4) are evenly distributed on the inner circumferential wall of the slot (11) outside the slope (22), and the shear studs (4) are connected to the inner circumferential wall of the slot (11) of the steel box girder (1) by welding.

4. The steel box girder and concrete pier fixed structure according to claim 1, characterized in that: The groove (11) is 1 to 2 m deep, and the concrete pier (2) located inside the groove (11) is uniformly filled with joint-sealing high-strength concrete.

5. The steel box girder and concrete pier fixed structure according to claim 1, characterized in that: Reinforcing ribs (12) are distributed on the steel box girder (1) on both sides of the slot (11), and the reinforcing ribs (12) are connected to the transverse diaphragm at the support point of the box girder on the steel box girder (1).

6. The steel box girder and concrete pier fixed structure according to claim 1, characterized in that: The outer surface of the concrete pier (2) located inside the groove (11) is provided with a roughened layer (23).

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