Prefabricated steel-UHPC composite structure and construction method

Abstract

The present invention relates to the technical field of bridge assembly, and in particular to an assembled steel-UHPC composite structure and a construction method, comprising a trough-shaped steel box installed on a top plate and a bottom plate of a side box arch rib to be reinforced, wherein a plurality of groups of supporting sleeves are arranged inside the trough-shaped steel box, a plurality of groups of perforated ribs are welded inside the trough-shaped steel box, chemical bolts are implanted inside each group of the supporting sleeves, the trough-shaped steel box is connected to the main arch side box arch rib of a concrete arch bridge through chemical bolts, the trough-shaped steel box cooperates with the perforated ribs to form a plurality of groups of concrete casting cavities, a first UHPC filling layer is cast inside the casting cavity, and after the first UHPC filling layer is solidified, it cooperates with the trough-shaped steel box and the chemical bolts to form a reinforcement surface for improving the structural strength on the side of the side box arch rib to be reinforced, thereby improving the structural strength.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge assembly, and in particular to an assembled steel-UHPC composite structure and a construction method. Background Art

[0002] Large-span concrete arch bridges have obvious economic advantages over concrete beam bridges with the same span. Therefore, a certain number of large-span prefabricated concrete box-slab arch bridges were built before 2010. However, the design load level of large-span prefabricated concrete box-slab arch bridges is not high, the defects at the longitudinal and transverse joints of the concrete box-slab arch are becoming increasingly prominent, and the seismic and impact toughness of the bridges are insufficient, and they are in urgent need of reinforcement and renovation.

[0003] At present, there are two types of reinforcement methods for long-span concrete arch bridges in the prior art:

[0004] 1. General maintenance, specifically crack repair and mortar joint shedding repair, is difficult to play a substantial reinforcement role, cannot improve the bearing capacity of the bridge, and poses a safety hazard;

[0005] 2. Outsourcing concrete reinforcement requires a large amount of work, high technical requirements, complex processes, a long construction period, and a heavy self-weight of the reinforced structure, which increases the load on the original main arch structure. Drilling and planting reinforcements cause great damage to the existing arch bridge, and the reliability of the combination of reinforced concrete and the original main arch is poor, while the mechanical properties of the reinforced structure depend on the combination of the new and old structures.

[0006] Therefore, a prefabricated steel-UHPC composite structure and construction method were proposed. Summary of the invention

[0007] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides an assembled steel-UHPC composite structure and a construction method.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: an assembled steel-UHPC composite structure, comprising a trough-shaped steel box installed on the top plate and bottom plate of the side box arch rib to be reinforced, a plurality of groups of supporting sleeves are arranged inside the trough-shaped steel box, a plurality of groups of perforated ribs are welded inside the trough-shaped steel box, a chemical bolt is implanted inside each group of the supporting sleeves, the trough-shaped steel box is connected to the main arch side box arch rib of the concrete arch bridge through the chemical bolts, the trough-shaped steel box cooperates with the perforated ribs to form a plurality of groups of concrete pouring cavities, and a first UHPC filling layer is poured inside the pouring cavity;

[0009] After the first UHPC filling layer is consolidated, a reinforcement surface is formed on the side of the arch rib of the side box to be reinforced in combination with a grooved steel box and chemical bolts to improve the structural strength.

[0010] Preferably, the trough-shaped steel box is an open trough-shaped box, the middle part of the trough-shaped steel box is parallel to the main arch side box arch ribs of the concrete arch bridge, and the two sides of the trough-shaped steel box are perpendicular to the main arch side box arch ribs of the concrete arch bridge.

[0011] Preferably, several groups of the support sleeves and several groups of perforated ribs are staggered, and each group of the support sleeves and perforated ribs is perpendicular to the middle of the trough-shaped steel box.

[0012] Preferably, the trough steel box, the supporting sleeve, the perforated rib plate, the first UHPC filling layer and the chemical bolts cooperate to form a prefabricated steel-concrete assembly, and two groups of prefabricated steel-concrete assemblies are respectively installed on the arch back and the arch rib of the main arch side box of the concrete arch bridge, and a tensile and compressive structural layer is formed between the two groups of prefabricated steel-concrete assemblies to generate a lateral connection between the two groups of prefabricated steel-concrete assemblies.

[0013] Preferably, the tensile and compressive structural layer includes a cross-connected steel plate, a cross-connected steel bar and a second UHPC filling layer, the cross-connected steel plate is welded between the opposite ends of the trough-shaped steel boxes of the two groups of prefabricated steel-concrete assemblies, the cross-connected steel bar is welded between the middle parts of the opposite ends of the trough-shaped steel boxes of the two groups of prefabricated steel-concrete assemblies, and the second UHPC filling layer is poured and formed in the cross-connected steel plate.

[0014] A construction method for an assembled steel-UHPC composite structure comprises the following steps:

[0015] Step A, determining the target concrete arch bridge main arch side box arch ribs that can be used for reinforcement and pre-processing the main arch side box arch ribs of the concrete arch bridge;

[0016] Step B, based on the bending moment of inertia of the reinforced front box arch rib section and the expected enhanced bending moment of inertia, calculate the specifications of the required prefabricated steel-UHPC composite structure components, and prepare the components for the prefabricated steel-UHPC composite structure;

[0017] Step C, installing the assembled arch rib area steel-UHPC composite structure on site;

[0018] Step D: Install the cross-connected steel plates on site and pour UHPC.

[0019] Preferably, the step A comprises:

[0020] Step A1, surveying the main arch of the target large concrete arch bridge, and determining the side box arch ribs on both sides of the main arch of the concrete arch bridge for reinforcement;

[0021] Step A2, roughening the top and bottom surfaces of the side box arch ribs, and cleaning the roughened surfaces after the roughening is completed;

[0022] Step A3, opening a plurality of bolt holes for installation work on the roughened surface, and implanting chemical bolts into the bolt holes.

[0023] Preferably, the step B comprises:

[0024] Step B1: Calculate the bending moment of inertia of the unreinforced front box arch rib section ;

[0025] Step B2, based on the bending moment of inertia of the unreinforced front box arch rib section , determine the converted bending moment of inertia of the reinforced section to be achieved after reinforcement ;

[0026] Step B3, establish the calculation formula 1 for the converted bending moment of inertia of the reinforced section,

[0027] ;

[0028] Step B4, establish the calculation formula 2 for the converted bending moment of inertia of the reinforced section,

[0029] ;

[0030] In calculation formulas 1 and 2, , , , and They are the elastic modulus of steel, original main arch ring concrete and newly added UHPC, To increase the cross-sectional area of ​​the steel structure, To add the cross-sectional area of ​​the first UHPC filling layer, is the width of the side box arch rib section, is the cross-sectional width of the first UHPC filling layer, is the cross-sectional area of ​​the side box arch rib;

[0031] Step B5, combine calculation formula 1 and calculation formula 2 to obtain the newly added steel structure cross-sectional area and the cross-sectional area of ​​the first newly added UHPC filling layer ,

[0032] Step B6: According to the newly added steel structure cross-sectional area and the fixed width of the steel structure, the required length of the trough steel box is obtained , the distance between two adjacent groups of trough steel boxes, that is, the length of the cross-connecting steel plate is The sum of the lengths of two adjacent sets of trough steel boxes and the cross-connecting steel plates is .

[0033] Preferably, the step C comprises:

[0034] Step C1, dividing the length of the desired trough steel box into four equal parts, and respectively arranging the trough steel boxes at both ends of the top surface and the bottom surface of the side box arch rib;

[0035] Step C2, implanting a plurality of groups of chemical bolts into a plurality of groups of supporting sleeves in the grooved steel box respectively;

[0036] Step C3, fixing the channel-shaped steel box on the surface of the side box arch rib using the implanted chemical bolts;

[0037] Step C4, pouring a first UHPC filling layer into the interior of the trough-shaped steel box, using the high fluidity of UHPC to make the first UHPC filling layer dense, thereby reducing the vibration of the concrete.

[0038] Preferably, the step D comprises:

[0039] Step D1, welding and connecting a set of cross-connecting steel plates between the ends of two sets of trough-shaped steel boxes on the same side of the side box arch rib;

[0040] Step D2, connecting a set of transverse steel bars between the middle parts of two sets of channel steel boxes on the same side of the side box arch rib;

[0041] Step D3, while pouring the first UHPC filling layer into the interior of the trough-shaped steel box, pour the second UHPC filling layer into the interior of the cross-connected steel plate, and use the high fluidity of UHPC to make the second UHPC filling layer dense, thereby reducing the vibration of the concrete.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] The present invention is provided with a grooved steel box, a supporting sleeve, a perforated rib plate, a first UHPC filling layer and chemical bolts. The grooved steel box cooperates with the perforated rib plate to form a plurality of groups of concrete pouring cavities, and the first UHPC filling layer is poured inside the pouring cavity. After the first UHPC filling layer is solidified, it cooperates with the grooved steel box and the chemical bolts to form a reinforcement surface to improve the structural strength on the side of the arch rib of the side box to be reinforced, thereby improving the strength of the arch rib of the side box;

[0044] In the present invention, a tensile-compressive structural layer is formed between two groups of prefabricated steel-concrete assemblies. The tensile-compressive structural layer includes a cross-connected steel plate, a cross-connected steel bar and a second UHPC filling layer, forming a reinforcement surface for improving the structural strength, further improving the strength of the side box arch rib. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the assembled steel-UHPC combined structure of the present invention;

[0046] Figure 2 It is a schematic diagram of the combined structure of the tensile and compressive structural layer of the present invention;

[0047] Figure 3This is a schematic diagram before reinforcement of the present invention;

[0048] Figure 4 It is a schematic diagram of the reinforcement process of the present invention;

[0049] Figure 5 It is a schematic diagram after reinforcement of the present invention;

[0050] Figure 6 It is a schematic diagram of the computing surface structure of the present invention.

[0051] The numbers in the figure represent:

[0052] 1. Trough steel box; 2. Support casing; 3. Perforated rib plate; 4. First UHPC filling layer; 5. Chemical bolts; 6. Cross-connecting steel plate; 7. Cross-connecting steel bars; 8. Second UHPC filling layer. DETAILED DESCRIPTION

[0053] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the following embodiments are merely preferred embodiments of the present invention and are not exhaustive.

[0054] Example:

[0055] like Figure 1-Figure 6 As shown, the present invention provides an assembled steel-UHPC composite structure, including a trough-shaped steel box 1 installed on the top plate and bottom plate of the side box arch rib to be reinforced, the trough-shaped steel box 1 is an open trough, the middle of the trough-shaped steel box 1 is parallel to the main arch side box arch rib of the concrete arch bridge, the two sides of the trough-shaped steel box 1 are perpendicular to the main arch side box arch rib of the concrete arch bridge, and the trough-shaped steel box 1 forms a space for pouring on the side of the main arch side box arch rib of the concrete arch bridge;

[0056] Several groups of supporting sleeves 2 are arranged inside the trough steel box 1, and several groups of perforated ribs 3 are welded inside the trough steel box 1. Several groups of supporting sleeves 2 and several groups of perforated ribs 3 are staggered, and each group of supporting sleeves 2 and perforated ribs 3 are perpendicular to the middle of the trough steel box 1;

[0057] Chemical bolts 5 are implanted inside each group of supporting sleeves 2, and the grooved steel box 1 is connected to the arch ribs of the main arch side boxes of the concrete arch bridge through the chemical bolts 5. The grooved steel box 1 cooperates with the perforated rib plates 3 to form several groups of concrete pouring cavities, and the first UHPC filling layer 4 is poured inside the pouring cavity.

[0058] The trough steel box 1, the supporting sleeve 2, the perforated rib plate 3, the first UHPC filling layer 4 and the chemical bolts 5 cooperate to form an assembled steel-concrete assembly. The two groups of assembled steel-concrete assemblies are respectively installed on the arch back and the arch rib of the main arch side box of the concrete arch bridge. A tensile and compressive structural layer is formed between the two groups of assembled steel-concrete assemblies. The tensile and compressive structural layer includes a cross-connecting steel plate 6, a cross-connecting steel bar 7 and a second UHPC filling layer 8. The cross-connecting steel plate 6 is welded between the opposite ends of the trough steel boxes 1 of the two groups of assembled steel-concrete assemblies. The cross-connecting steel bar 7 is welded between the middle parts of the opposite ends of the trough steel boxes 1 of the two groups of assembled steel-concrete assemblies. The second UHPC filling layer 8 is poured and formed in the cross-connecting steel plate 6.

[0059] A construction method for an assembled steel-UHPC composite structure comprises the following steps:

[0060] Determine the target concrete arch bridge main arch side box arch ribs that can be used for reinforcement, and pre-treat the concrete arch bridge main arch side box arch ribs;

[0061] Survey the main arch of the target large concrete arch bridge, determine the side box arch ribs on both sides of the main arch of the concrete arch bridge for reinforcement, roughen the top and bottom surfaces of the side box arch ribs, clean the roughened surfaces after roughening to keep them clean and free of floating dust, and open several groups of bolt holes for installation work on the roughened surfaces;

[0062] Arch bridges are pressure-bearing components. The increase in the converted cross-sectional area can effectively reduce the compressive stress of the main arch ring under the action of axial force. Before reinforcement, the bending moment of inertia of the arch rib section of the unreinforced front box is calculated. , based on the bending moment of inertia of the unreinforced front box arch rib section , determine the converted bending moment of inertia of the reinforced section to be achieved after reinforcement , establish the calculation formula 1 for the converted bending moment of inertia of the reinforced section,

[0063] ;

[0064] Establish the calculation formula 2 for the converted bending moment of inertia of the reinforced section.

[0065] ;

[0066] In calculation formulas 1 and 2, , , , and They are the elastic modulus of steel, original main arch ring concrete and newly added UHPC, To increase the cross-sectional area of ​​the steel structure, To add the cross-sectional area of ​​the first UHPC filling layer, is the width of the side box arch rib section, is the cross-sectional width of the first UHPC filling layer, is the cross-sectional area of ​​the side box arch rib;

[0067] Combined calculation formula 1 and calculation formula 2, the new steel structure cross-sectional area is obtained as and the cross-sectional area of ​​the first newly added UHPC filling layer ;

[0068] According to the new steel structure cross-sectional area and the fixed width of the steel structure, the required length of the trough steel box is obtained , the distance between two adjacent groups of trough steel boxes, that is, the length of the cross-connecting steel plate is The sum of the lengths of two adjacent sets of trough steel boxes and the cross-connecting steel plates is After the bolt holes are opened, components for the assembled steel-UHPC composite structure are prepared. The assembled steel-UHPC composite structure is provided with a grooved steel box 1 at both ends of the top and bottom surfaces of the side box arch ribs. Several groups of chemical bolts 5 are respectively implanted into several groups of supporting sleeves 2 in the grooved steel box 1. The chemical bolts 5 are connected to the threaded holes opened in the side box arch ribs. The grooved steel box 1 is fixed to the surface of the side box arch ribs with the cooperation of the chemical bolts 5 and the threaded holes.

[0069] Assemble the tensile and compressive structural layer, weld and connect a set of cross-connecting steel plates 6 between the ends of the two groups of trough steel boxes 1 on the same side of the side box arch rib, connect a set of cross-connecting steel bars 7 between the middle parts of the two groups of trough steel boxes 1 on the same side of the side box arch rib, pour a second UHPC filling layer 8 into the cross-connecting steel plate 6, and vibrate the second UHPC filling layer 8 poured into the cross-connecting steel plate 6 to make the second UHPC filling layer 8 dense, pour a first UHPC filling layer 4 into the trough steel box 1, and vibrate the first UHPC filling layer 4 poured into the trough steel box 1 to make the first UHPC filling layer 4 dense;

[0070] The bridges that have been reinforced are calculated, and the equivalent data after reinforcement are calculated using Formula 1 and Formula 2. The statistical results are shown in Table 1.

[0071] Table 1. Calculation value table after reinforcement

[0072]

[0073] From the data statistics in Table 1, it can be seen that if the added UHPC area reaches 20% of the cross-sectional area of ​​the side box arch rib to be reinforced, the converted area can be increased by more than 45%, and the section moment of inertia can be increased by more than 60%.

[0074] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive of the present invention. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims of the present invention, but all of them will fall within the scope of protection of the present invention.

Claims

1. Prefabricated steel-UHPC composite structure, characterized in that: It includes a trough steel box installed on the top plate and bottom plate of the arch rib of the side box to be reinforced, wherein a plurality of groups of supporting sleeves are arranged inside the trough steel box, a plurality of groups of perforated ribs are welded inside the trough steel box, a chemical bolt is implanted inside each group of the supporting sleeves, the trough steel box is connected to the arch rib of the main arch side box of the concrete arch bridge through the chemical bolts, the trough steel box cooperates with the perforated ribs to form a plurality of groups of concrete casting cavities, and a first UHPC filling layer is cast inside the casting cavity; The grooved steel box, the support sleeve, the perforated rib plate, the first UHPC filling layer and the chemical bolts cooperate to form an assembled steel-concrete assembly. Two groups of assembled steel-concrete assemblies are respectively installed on the arch back and the arch rib of the main arch side box of the concrete arch bridge. A tensile and compressive structural layer for generating a lateral connection between the two groups of assembled steel-concrete assemblies is formed between the two groups of assembled steel-concrete assemblies. The tensile and compressive structural layer includes a cross-connected steel plate, a cross-connected steel bar and a second UHPC filling layer. The cross-connected steel plate is welded between the opposite ends of the grooved steel boxes of the two groups of assembled steel-concrete assemblies. The cross-connected steel bar is welded between the middle parts of the opposite ends of the grooved steel boxes of the two groups of assembled steel-concrete assemblies. The second UHPC filling layer is poured and formed in the cross-connected steel plate. After the first UHPC filling layer is consolidated, a reinforcement surface is formed on the side of the arch rib of the side box to be reinforced in combination with a grooved steel box and chemical bolts to improve the structural strength.

2. The assembled steel-UHPC composite structure according to claim 1, characterized in that: The trough-shaped steel box is an open trough-shaped box, the middle of which is parallel to the main arch side box arch ribs of the concrete arch bridge, and the two sides of which are perpendicular to the main arch side box arch ribs of the concrete arch bridge.

3. The assembled steel-UHPC composite structure according to claim 2, characterized in that: A plurality of groups of the support sleeves and a plurality of groups of the perforated ribs are staggeredly arranged, and each group of the support sleeves and the perforated ribs are perpendicular to the middle of the trough-shaped steel box.

4. A construction method for the assembled steel-UHPC composite structure according to claim 3, characterized in that: The following steps are included: Step A, determining the target concrete arch bridge main arch side box arch ribs that can be used for reinforcement and pre-processing the main arch side box arch ribs of the concrete arch bridge; Step B, based on the bending moment of inertia of the reinforced front box arch rib section and the expected enhanced bending moment of inertia, calculate the specifications of the required prefabricated steel-UHPC composite structure components, and prepare the components for the prefabricated steel-UHPC composite structure; Step C, installing the assembled arch rib area steel-UHPC composite structure on site; Step D: Install the cross-connected steel plates on site and pour UHPC.

5. The construction method of the assembled steel-UHPC composite structure according to claim 4, characterized in that: The step A comprises: Step A1, surveying the main arch of the target large concrete arch bridge, and determining the side box arch ribs on both sides of the main arch of the concrete arch bridge for reinforcement; Step A2, roughening the top and bottom surfaces of the side box arch ribs, and cleaning the roughened surfaces after the roughening is completed; Step A3, opening a plurality of bolt holes for installation work on the roughened surface, and implanting chemical bolts into the bolt holes.

6. The construction method of the assembled steel-UHPC composite structure according to claim 4, characterized in that: The step B comprises: Step B1: Calculate the bending moment of inertia I of the unreinforced front box arch rib section c ; Step B2, based on the bending moment of inertia I of the unreinforced front box arch rib section c , determine the converted bending moment of inertia I0 of the reinforced section to be achieved after reinforcement; Step B3, establish the calculation formula 1 for the converted bending moment of inertia of the reinforced section, Step B4, establish the calculation formula 2 for the converted bending moment of inertia of the reinforced section, In calculation formulas 1 and 2, E s 、E UHPC and E c are the elastic modulus of steel, original main arch ring concrete and newly added UHPC, A s A is the newly added steel structure cross-sectional area. uc is the cross-sectional area of ​​the first newly added UHPC filling layer, h c is the width of the side box arch rib section, h uc is the cross-sectional width of the first UHPC filling layer, A c is the cross-sectional area of ​​the side box arch rib; Step B5, combine calculation formula 1 and calculation formula 2 to obtain the newly added steel structure cross-sectional area A s and the cross-sectional area of ​​the first newly added UHPC filling layer A uc ; Step B6: According to the newly added steel structure cross-sectional area A s and the fixed width of the steel structure, the required length B of the trough steel box is obtained s The distance between two adjacent groups of trough steel boxes, that is, the length of the cross-connecting steel plate, is B. r , the sum of the lengths of two adjacent groups of trough steel boxes and the cross-connecting steel plates is B.

7. The construction method of the assembled steel-UHPC composite structure according to claim 4, characterized in that: The step C comprises: Step C1, dividing the length of the desired trough steel box into four equal parts, and respectively arranging the trough steel boxes at both ends of the top surface and the bottom surface of the side box arch rib; Step C2, implanting a plurality of groups of chemical bolts into a plurality of groups of supporting sleeves in the grooved steel box respectively; Step C3, fixing the channel steel box to the side box arch rib surface by using the implanted chemical bolts; Step C4, pouring a first UHPC filling layer into the interior of the trough-shaped steel box, and making the first UHPC filling layer dense by utilizing the high fluidity of UHPC.

8. The construction method of the assembled steel-UHPC composite structure according to claim 4, characterized in that: The step D comprises: Step D1, welding a set of cross-connecting steel plates between the ends of two sets of trough-shaped steel boxes on the same side of the side box arch rib; Step D2, connecting a set of transverse steel bars between the middle parts of two sets of channel steel boxes on the same side of the side box arch rib; Step D3, while pouring the first UHPC filling layer into the interior of the trough-shaped steel box, pour the second UHPC filling layer into the interior of the cross-connected steel plate, and use the high fluidity of UHPC to make the second UHPC filling layer dense.

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