Construction method suitable for suspended splicing rapid construction of UHPC composite beam segments

Abstract

The invention discloses a construction method suitable for suspended splicing rapid construction of UHPC (Ultra High Performance Concrete) composite beam segments and a construction method thereof, which are applied to connection construction of the composite beam segments consisting of a composite bridge deck slab and a steel main beam, and the composite bridge deck slab at least consists of an upper UHPC bridge deck slab and a lower bridge deck slab steel bottom plate. Welding and connecting a side web plate of the steel main beam, a bottom plate of the steel main beam, a middle web plate of the steel main beam and the bridge deck slab steel bottom plate at the joint of each composite beam section to form an annular welding joint of the composite beam sections; the circumferential welding joints of the adjacent composite beam sections are welded and connected through the PBL steel structure inlaying sections to form a complete closed steel box. The wet joint lagging construction can be realized.

Description

Technical Field

[0001] The invention relates to the field of UHPC composite beams, and in particular to a construction method suitable for rapid construction of suspended assembly of UHPC composite beam segments. Background Art

[0002] The bridge deck of the composite bridge is made of ultra-high performance concrete (UHPC) with high tensile and compressive strength, low chloride ion diffusion coefficient, zero shrinkage after steam curing and small creep. It can effectively avoid problems that have long plagued the engineering community, such as fatigue cracking caused by using only orthotropic steel bridge decks, easy damage to bridge deck pavement, and easy cracking of ordinary concrete bridge decks.

[0003] Since the maintenance of wet joints of bridge decks takes time, it usually takes 12 to 14 days to construct a segment of composite beam suspension. For large-span cable-stayed bridges, the use of UHPC composite beams in the main beam can give full play to the excellent performance of UHPC. Now there are more and more application cases. However, if the conventional composite beam suspension process is used, it still takes 10 to 12 days to construct a standard segment. For coastal areas facing the impact of typhoons, the need to accelerate the construction of composite beam suspension to avoid the typhoon period is imminent.

[0004] In conventional cable-stayed bridges, the cables are tensioned twice. When the cable is tensioned once, the bridge crane can be unloaded. After unloading, the weight of the new beam section is borne by the cable. When the cable is tensioned twice, the bridge deck is directly adjusted to the design cable force. Under the action of the design cable force, the compressive stress reserve of the bridge deck is not very large. When the next beam section is hoisted, the bridge deck is likely to be subjected to a large tensile stress and crack.

[0005] Chinese patent CN201710853512.6 discloses "A UHPC composite bridge deck with self-contained formwork", and CN201910603313.9 discloses "A UHPC composite bridge with self-contained stiffening formwork". The composite bridge decks they use include a UHPC bridge deck and a steel bottom plate of the bridge deck below it, and the upper plate surface of the steel bottom plate is welded with a PBL shear connector for connecting the UHPC bridge deck. For this type of composite bridge deck, it is advisable to research and develop a construction method that can be constructed quickly. Summary of the invention

[0006] The invention provides a construction method suitable for the rapid construction of suspended assembly of UHPC composite beam segments, which can delay the construction of wet joints, is convenient for construction, has high work efficiency, and can greatly reduce the construction period.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A construction method suitable for rapid cantilever construction of UHPC composite beam segments, which is applied to the connection construction of composite beam segments composed of a composite bridge deck and a steel main beam, wherein the composite bridge deck is composed of at least an upper UHPC bridge deck and a lower bridge deck steel bottom plate, comprising the following steps:

[0009] S00. Cast the UHPC bridge deck on the steel main beam in one go to form a composite beam segment and steam cure it;

[0010] S10. The No. 1 composite beam segment is hoisted and after hoisting to the installation position, the position of the composite beam segment is matched and positioned. One No. 1 inclined cable corresponding to the No. 1 composite beam segment is installed, including the tower end hanging cable, the beam end cable insertion and anchoring of the No. 1 inclined cable, and the inclined cable is tensioned. The bridge deck crane is unloaded. After unloading, the weight of the No. 1 composite beam segment is borne by the inclined cable. There are two No. 1 inclined cables, and the two inclined cables are over-tensioned.

[0011] S20. Lifting the No. 2 composite beam segment, and after lifting it to the installation position, performing position matching and positioning of the composite beam segment;

[0012] S30. The steel structure of the No. 2 composite beam segment is connected to the steel structure of the No. 1 composite beam segment by T-shaped welding;

[0013] S40. One No. 2 stay cable corresponding to the No. 2 composite beam segment, including the tower end hanging cable of the No. 2 stay cable, the beam end cable insertion and anchoring, and the cable tensioning, and the bridge deck crane unloading. After unloading, the weight of the No. 2 composite beam segment is borne by the stay cable;

[0014] S50. The steel structure of the No. 2 composite beam segment is connected to the No. 1 composite beam segment. When the adjacent composite beam segments are connected, the matching parts and the yard plates are first used to match and locate and fix the positions of the two adjacent composite beam segments. Then, the side webs of the steel main beams, the bottom plates of the steel main beams, the middle webs of the steel main beams and the steel bottom plates of the bridge deck at the connection of each composite beam segment are welded to form the circumferential welded seams of the composite beam segments. The circumferential welded seams of the adjacent composite beam segments are welded to form a completed closed steel box through the PBL steel structure patching sections.

[0015] S60. Two No. 2 inclined cables corresponding to the No. 2 composite beam segment, the two inclined cables are over-tensioned, and three No. 1 inclined cables corresponding to the No. 1 composite beam segment, the three inclined cables are tensioned;

[0016] S70. Lift the No. 3 composite beam segment, and after lifting it to the installation position, perform position matching and positioning of the composite beam segment;

[0017] S80. The steel structure of the No. 3 composite beam segment is connected to the steel structure of the No. 2 composite beam segment by T-shaped welding;

[0018] S90. One No. 3 stay cable corresponding to the No. 3 composite beam segment, including the tower end hanging cable, beam end cable insertion and cable tensioning of the No. 3 stay cable, and the unloading of the bridge deck crane. After unloading, the weight of the No. 3 composite beam segment is borne by the stay cable;

[0019] S100. The steel structure of the No. 3 composite beam segment is connected to the No. 2 composite beam segment. When the adjacent composite beam segments are connected, the matching parts and the yard plates are first used to match and locate and fix the positions of the two adjacent composite beam segments. Then, the side webs of the steel main beams, the bottom plates of the steel main beams, the middle webs of the steel main beams and the steel bottom plates of the bridge deck at the connection of each composite beam segment are welded to form the circumferential welded seams of the composite beam segments. The circumferential welded seams of the adjacent composite beam segments are welded to form a completed closed steel box through the PBL steel structure patching sections.

[0020] S110. Wet joint reinforcement connection and casting between composite beam segment No. 1 and composite beam segment No. 2;

[0021] S120. Two cables No. 3, two cables are over-tensioned, and three cables No. 2, three cables are tensioned;

[0022] S130. The track jack pushes the whole machine to make the spliced ​​composite beam segment move forward a standard beam segment length;

[0023] S140. Similarly, referring to step S70 to step S130, install and connect composite beam segments No. 4 to N, and sequentially perform wet joint reinforcement connection and pouring between composite beam segment No. 2 and composite beam segment No. 3, wet joint reinforcement connection and pouring between composite beam segment No. 3 and composite beam segment No. 4, and wet joint reinforcement connection and pouring between composite beam segment No. N and composite beam segment No. N+1, where N is a positive integer, N≥4.

[0024] When the composite beam segments of the present invention are cantilevered, the steel bottom plate of the bridge deck below the UHPC bridge deck, the steel main beam segments and the PBL patching segments are connected to form a complete closed steel box. Although the UHPC of the wet joint is not cast and the UHPC bridge deck is not continuously connected, the steel bottom plate below the UHPC bridge deck has made the entire bridge deck steel structure continuously connected, and the force can be normally transmitted between the two steel main beam segments, thereby achieving the purpose of delayed construction of the wet joint.

[0025] The present invention also has the following preferred design:

[0026] The steps S50 and S100 described in the present invention both include: inspecting the circumferential welding seams, and after the welding seams are of good quality, welding the bottom plate stiffening ribs and side web stiffening ribs of the steel main beam and welding the PBL steel structure patching section. The bottom plate and side web stiffening ribs are provided to improve the local and overall stability of the steel structure so that it will not become unstable and damaged due to large external loads.

[0027] In step S00 of the present invention, the casting of the UHPC bridge deck includes the installation of bridge deck reinforcement, embedded sleeves of crash barrier bolts, cable conduits, embedded pipes of lighting cables, embedded pipes of temporary hanging points, embedded steel plates of dampers, installation of formwork and roughening-free tape, and casting of UHPC. After casting the UHPC, the film is covered for moisturizing maintenance for about 36 hours. After the UHPC is finally set, the side formwork is removed, and then high-temperature steam curing at 90°C for 48 hours is carried out. After the UHPC is steam-cured, the surface of the UHPC bridge deck is covered with geotextile, and watering is continued for moisturizing maintenance for 7 days.

[0028] The T-shaped welding connection of the present invention refers to the welding connection of a T-shaped member composed of the side webs and the flanges on the side webs of two adjacent composite beam segment steel main beams.

[0029] The cable force value of one of the inclined cables of the present invention is determined by calculation, and it is necessary to balance most of the deadweight of the composite beam segment where the inclined cable is located and to make the joint of the T-shaped welded connection bear less stress.

[0030] More preferably, the inclined cable needs to be graded and coordinated according to the force, and the bridge crane actively unloads in three stages. When the cable force value of the inclined cable is about 60%, the bridge crane actively unloads about 20% of the load; when the cable force value of the inclined cable is about 80%, the bridge crane actively unloads about 50% of the load; when the cable force value of the inclined cable is 100%, the bridge crane actively unloads 100% of the load.

[0031] The UHPC between adjacent composite beam segments of the present invention is cast into a UHPC wet joint in one continuous casting, and no joints are allowed in the middle. The addition of high-strength fine steel fibers is one of the main reasons for the excellent mechanical properties of UHPC. The UHPC bridge deck is cast into a UHPC bridge deck in one continuous casting to avoid the degradation of mechanical properties caused by the interruption of steel fibers in the bridge deck joints within the segment.

[0032] The present invention removes the surface slurry from the joint surface between adjacent composite beam segments by chiseling, adopts manual mechanical chiseling, and the chiseling depth is controlled at 5-10 mm. No loose residue and powder shall be left after chiseling. After chiseling, it is cleaned in time and wet joint UHPC is poured.

[0033] Before pouring the wet joints between adjacent composite beam segments, the debris in the wet joints is cleaned and the UHPC joint surface is fully moistened for no less than 24 hours to ensure that the joints between the wet joint UHPC and the prefabricated board are tight.

[0034] After the pouring and vibration of the wet joints between adjacent composite beam segments of the present invention are completed, the surface is manually plastered and covered with a moisturizing film for wet curing. After wet curing for 48 hours, the joints are steam-cured. Steam curing is adopted for the wet joint UHPC, and the steam curing is carried out at a constant temperature of 63° C. to 68° C. for 72 hours. The steam curing coverage area is larger than the wet joint area, and the wet joint is steam-cured when the width is more than 500 mm around.

[0035] The second tensioning of the cable-stayed cable described in the present invention is over-tensioned, and the tensioning force exceeds the theoretical cable force of the cable. Sufficient pre-compression stress is applied on the bridge deck and the wet joint to reserve compressive stress for the hoisting of the next section of the composite beam segment. The tensioning force needs to take into account the stress of the bridge deck and the padding of the tensioning end of the cable. It is better if no additional padding is required.

[0036] The three-tensioning process of the inclined cable of the present invention is a tensioning process. When the wet joint tensile stress meets the allowable stress, the over-tensioned cable force is adjusted to the designed cable force.

[0037] According to the present invention, the construction sequence of the two inclined cables of the rear composite beam segment and the three inclined cables of the front composite beam segment is interchanged according to the stress conditions.

[0038] The present invention can adjust the construction sequence of the wet joint reinforcement connection at the front end and the rear end of the composite beam segment and the UHPC casting and curing according to design requirements.

[0039] Before the strength of the wet joint UHPC between adjacent composite beam segments of the present invention reaches 85% of the design strength grade, vehicles shall not pass on the bridge deck, materials shall not be piled up, or other construction operations that affect its stress shall not be carried out. During the wet joint moisturizing stage, the hoisting operation of the lower segment beam cannot be carried out.

[0040] The present invention has the following beneficial effects

[0041] 1. The composite beam segment of the present invention is integrally cast in a factory at one time and steam-cured in a factory, and integrally hoisted on site, eliminating the wet joint operation in each segment, and the construction is simple and fast.

[0042] 2. When the composite beam segments of the present invention are suspended, a complete closed steel box is formed by connecting the bridge deck steel bottom plate, the steel main beam and the PBL steel structure patching section. The wet joints between the segments can be cast later. The suspension process and efficiency of the UHPC composite beam are basically the same as those of the orthotropic steel main beam. The standard segment construction period is 6 to 8 days, which greatly improves the suspension construction efficiency of the composite beam cable-stayed bridge.

[0043] 3. When the segments of the present invention are suspended, the two cables are over-tensioned, and sufficient pre-stress is applied to the bridge deck and wet joints to reserve compressive stress for the next section of the composite beam segment to avoid the cracking of the bridge deck. The main beam UHPC bridge deck has a low construction stress level, and there is no need to set temporary prestressing for construction. The structure is simple and the construction is convenient.

[0044] 4. The composite beam of the present invention can be any one of a PK composite beam, a fully enclosed steel box composite beam, a double-sided box composite beam, an I-shaped composite beam, and a steel truss composite beam, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic structural diagram of an S-UHPC composite beam bridge in the longitudinal direction of the bridge in Example 1;

[0046] Figure 2 It is a structural schematic diagram of the wet joint range between the composite beam segments of the present invention;

[0047] Figure 3 is a cross-sectional structural diagram of a composite beam bridge in an embodiment;

[0048] Figure 4 yes Figure 4 Structural diagram of T-shaped connections between segments of a medium composite beam bridge;

[0049] Figure 5 It is a construction flow chart of the present invention;

[0050] Figure 6 It is a structural schematic diagram of a UHPC composite beam segment cantilever construction of the present invention;

[0051] Figure 7 It is a schematic structural diagram of a UHPC composite beam bridge along the bridge direction in Example 2.

[0052] Explanation of the accompanying numbers: 1-bridge deck, 2-bridge deck steel bottom plate, 3-PBL shear key, 4-PBL steel structure patch section, 5-bottom plate of steel main beam, 6-middle web of steel main beam, 7-side web of steel main beam, 8-upper flange of side web, 9-bottom plate stiffening rib, 10-side web stiffening rib. DETAILED DESCRIPTION

[0053] The following surface describes the technical solution of the present invention in detail in combination with the accompanying drawings and embodiments, so that ordinary technicians in the field can better understand and implement the technical solution of the present invention.

[0054] Example 1

[0055] A construction method suitable for rapid construction of UHPC composite beam segments, which is applied to Figures 1 to 4The composite bridge deck and the steel main beam are connected to form a composite beam segment, wherein the composite bridge deck is composed of at least an upper UHPC bridge deck 1 and a lower bridge deck steel bottom plate 2, combined with Figure 5 The construction method of the present invention comprises the following steps:

[0056] S00. One-time integral casting of UHPC bridge deck 1 on the steel main beam to form a composite beam segment and steam curing;

[0057] As a preferred embodiment, casting of the UHPC bridge deck 1 includes the installation of bridge deck reinforcement, embedded sleeves of crash barrier bolts, cable guide tubes, embedded lighting cable pipes, embedded temporary hanging point pipes, embedded damper steel plates, templates and non-chisel tape installation and UHPC casting. After casting the UHPC, the film is covered for moisturizing maintenance for about 36 hours. After the UHPC is finally set, the side formwork is removed, and then high-temperature steam curing at 90° C. for 48 hours is carried out. After the UHPC is steam cured, the surface of the UHPC bridge deck is covered with geotextiles, and watering is continued for moisturizing maintenance for 7 days.

[0058] S10. The No. 1 composite beam segment is hoisted and after hoisting to the installation position, the position of the composite beam segment is matched and positioned. One No. 1 inclined cable corresponding to the No. 1 composite beam segment is installed, including the tower end hanging cable, the beam end cable insertion and anchoring of the No. 1 inclined cable, and the inclined cable is tensioned. The bridge deck crane is unloaded. After unloading, the weight of the No. 1 composite beam segment is borne by the inclined cable. There are two No. 1 inclined cables, and the two inclined cables are over-tensioned.

[0059] S20. Lifting the No. 2 composite beam segment, and after lifting it to the installation position, performing position matching and positioning of the composite beam segment;

[0060] S30. The steel structure of the No. 2 composite beam segment is connected to the steel structure of the No. 1 composite beam segment by T-shaped welding;

[0061] S40. One No. 2 stay cable corresponding to the No. 2 composite beam segment, including the tower end hanging cable of the No. 2 stay cable, the beam end cable insertion and anchoring, and the cable tensioning, and the bridge deck crane unloading. After unloading, the weight of the No. 2 composite beam segment is borne by the stay cable;

[0062] S50. The steel structure of the No. 2 composite beam segment is connected to the No. 1 composite beam segment. When the adjacent composite beam segments are connected, the matching parts and the yard plates are first used to match and locate and fix the positions of the two adjacent composite beam segments. Then, the side webs 7 of the steel main beam, the bottom plate 5 of the steel main beam, the middle webs 6 of the steel main beam and the steel bottom plate 1 of the bridge deck at the connection of each composite beam segment are welded to form the circumferential welded seams of the composite beam segment. The circumferential welded seams of the adjacent composite beam segments are welded to form a completed closed steel box through the PBL steel structure patching section 4.

[0063] S60. Two No. 2 inclined cables corresponding to the No. 2 composite beam segment, the two inclined cables are over-tensioned, and three No. 1 inclined cables corresponding to the No. 1 composite beam segment, the three inclined cables are tensioned;

[0064] S70. Lift the No. 3 composite beam segment, and after lifting it to the installation position, perform position matching and positioning of the composite beam segment;

[0065] S80. The steel structure of the No. 3 composite beam segment is connected to the steel structure of the No. 2 composite beam segment by T-shaped welding;

[0066] S90. One No. 3 stay cable corresponding to the No. 3 composite beam segment, including the tower end hanging cable, beam end cable insertion and cable tensioning of the No. 3 stay cable, and the unloading of the bridge deck crane. After unloading, the weight of the No. 3 composite beam segment is borne by the stay cable;

[0067] S100. The steel structure of the No. 3 composite beam segment is connected to the No. 2 composite beam segment. When the adjacent composite beam segments are connected, the matching parts and the yard plates are first used to match and locate and fix the positions of the two adjacent composite beam segments. Then, the side webs 7 of the steel main beam, the bottom plate 5 of the steel main beam, the middle webs 6 of the steel main beam and the steel bottom plate 1 of the bridge deck at the connection of each composite beam segment are welded to form the circumferential welded seams of the composite beam segments. The circumferential welded seams of the adjacent composite beam segments are welded to form a completed closed steel box through the PBL steel structure patching section 4.

[0068] S110. Wet joint reinforcement connection and pouring between composite beam segment No. 1 and composite beam segment No. 2, including roughening and cleaning of joint surface, installation of wet joint reinforcement, mixing, transportation, material placement, vibration and leveling of wet joint UHPC, secondary finishing, film coating and steam curing;

[0069] S120. Two cables No. 3, two cables are over-tensioned, and three cables No. 2, three cables are tensioned;

[0070] S130. The bridge crane is moved forward and anchored, including loosening the bridge deck latch at the rear anchor point of the bridge crane, using the track jack to push the entire crane forward by a standard beam section length, and retrieving the lifting jack to reconnect the new bridge deck lifting lug at the rear anchor point;

[0071] S140. Similarly, referring to step S70 to step S130, install and connect composite beam segments No. 4 to N, and sequentially perform wet joint reinforcement connection and pouring between composite beam segment No. 2 and composite beam segment No. 3, wet joint reinforcement connection and pouring between composite beam segment No. 3 and composite beam segment No. 4, and wet joint reinforcement connection and pouring between composite beam segment No. N and composite beam segment No. N+1, where N is a positive integer, N≥4.

[0072] In one embodiment, both step S50 and step S100 include: inspecting the circumferential weld seams, and after the quality of the weld seams is in good condition, welding the bottom plate stiffening ribs 9 and the side web stiffening ribs 10 of the steel main beam and the PBL steel structure patching section 4, and then inspecting the welds.

[0073] In one embodiment, if Figure 4 As shown, the T-shaped welding connection refers to the welding connection of the T-shaped member composed of the side web 7 and the upper flange 8 of the side web of the steel main beam of two adjacent composite beam segments. The bottom plate 5 of the steel main beam, the middle web 6 of the steel main beam, the flange plate of the middle web, plus the side web 7 and the side web flange 8 of the steel main beam that have been previously connected by T-shaped welding are connected to form a circumferential welded seam of the composite beam segment.

[0074] In this embodiment, the cable force value of each inclined cable is determined according to calculation, and it is necessary to balance most of the deadweight of the composite beam segment where the inclined cable is located and to make the joint of the T-shaped welded connection bear less stress.

[0075] In one embodiment, the inclined cable needs to be graded and coordinated with each other according to the force, and the bridge crane actively unloads in three stages. When the cable force value of the inclined cable is about 60%, the bridge crane actively unloads about 20% of the load; when the cable force value of the inclined cable is about 80%, the bridge crane actively unloads about 50% of the load; when the cable force value of the inclined cable is 100%, the bridge crane actively unloads 100% of the load.

[0076] In one embodiment, the UHPC between adjacent composite beam segments is continuously poured at one time to form a UHPC wet joint, and no joints are allowed in between.

[0077] In one embodiment, the surface slurry is chiseled off the joint surface between adjacent composite beam segments, and the chiseling is performed manually and mechanically. The chiseling depth is controlled at 5 to 10 mm. No loose residue and powder should be left after the chiseling. After the chiseling is completed, the joint surface is cleaned and wet joint UHPC is poured in time.

[0078] In one embodiment, before pouring the wet joints between adjacent composite beam segments, the debris in the wet joints is cleaned and the UHPC joint surface is fully moistened for no less than 24 hours to ensure that the joints between the wet joint UHPC and the precast panels are tight.

[0079] In one embodiment, after the pouring and vibration of the wet joints between adjacent composite beam segments are completed, the joints are manually plastered and covered with a moisturizing film for wet curing. After wet curing for 48 hours, the joints are steam-cured. Steam curing is adopted for the wet joint UHPC, and the steam curing is carried out at a constant temperature of 63°C to 68°C for 72 hours. The steam curing coverage area is larger than the wet joint area, and the wet joint is steam-cured when the width is more than 500 mm around.

[0080] In the present embodiment, the second cable-stayed cable is over-tensioned, and the tensioning force exceeds the theoretical cable force of the cable. Sufficient pre-stress is applied on the bridge deck and the wet joint to reserve compressive stress for the hoisting of the next section of the composite beam segment. The tensioning force needs to take into account the stress of the bridge deck and the padding of the tensioned end of the cable. It is better if no additional padding is required.

[0081] In this embodiment, the three-stayed cable is in the tensioning process, and when the wet joint tensile stress meets the allowable stress, the over-tensioned cable force is adjusted to the designed cable force.

[0082] In one embodiment, the construction order of the two inclined cables of the subsequent composite beam segment and the three inclined cables of the previous composite beam segment is interchanged according to the stress conditions. For example, in step S120, the construction order of the two inclined cables No. 3 and the three inclined cables No. 2 can be interchanged according to the stress conditions.

[0083] The second cable-stayed cable in the present invention is over-tensioned, and sufficient pre-compression stress is applied on the bridge deck and the wet joint to reserve compressive stress for the hoisting of the next section of the composite beam segment, thereby avoiding the problem of cracking of the bridge deck. The third cable-stayed cable is in the tensioning process. When the tensile stress of the wet joint meets the allowable stress, the cable force can be adjusted to the designed cable force.

[0084] In one embodiment, the construction sequence of the wet joint reinforcement connection between the front and rear bridge decks of the composite beam segment and the UHPC casting and curing can be adjusted according to the design requirements. The project research based on which the present invention is based shows that the wet joint can be cast after 3 segments, but after 2 segments, the rapid construction requirements are met, so the present invention recommends casting the wet joint after 2 segments. Figure 6 , the application example is as follows: for the No. 2 composite beam segment, its front wet joint is recorded as the No. 2 wet joint, and its rear wet joint is recorded as the No. 3 wet joint. The No. 2 wet joint is constructed after the No. 4 composite beam segment and the No. 5 composite beam segment complete the steel structure connection to form a closed steel box according to step S100, and the No. 2 wet joint is constructed after the No. 4 composite beam segment is connected; for the No. 3 wet joint, it can be constructed after the No. 5 composite beam segment is connected or the No. 6 composite beam segment is connected. Compared with the existing construction method, the wet joint can be cast later, and the construction time of the wet joint steel bar connection and UHPC casting can be delayed by 2 to 3 segments. The UHPC composite beam suspension splicing process and efficiency are basically the same as those of the orthotropic steel main beam. The standard segment construction period is 6 to 8 days, which greatly improves the efficiency of the composite beam cable-stayed bridge suspension splicing construction. The wet joint lag time is determined comprehensively according to the stress conditions and construction organization requirements.

[0085] In one embodiment, before the strength of the UHPC wet joints between adjacent composite beam segments reaches 85% of the design strength grade, vehicles shall not pass on the bridge deck, materials shall not be stacked, or other construction operations that affect its stress shall not be carried out, and the lifting operation of the lower segment beam cannot be carried out during the wet joint moisturizing stage.

[0086] In one embodiment, the steps of lifting the composite beam segment generally include anchoring and positioning after the beam transport ship is transported to the position and lifting and lifting the composite beam segment with a bridge crane; the transportation by beam transport ship includes obtaining the consent of the maritime department, publishing navigation dynamics, and transporting the beam transport ship to the bridge site; anchoring and positioning includes the beam transport ship adjusting the position, dropping the positioning anchor and the main stern anchor, etc. After the composite beam segment is lifted and leaves the deck of the beam transport ship for a certain distance, the anchor boat immediately lifts the anchor and evacuates the site.

[0087] In the present invention, the matching piece and the yard plate are not components of the composite beam, but are only temporary auxiliary positioning and fixing workpieces used in the process of cantilever assembly construction of composite beam segments.

[0088] Example 2

[0089] like Figure 7 As shown, the difference from Example 1 is that in this embodiment, between the adjacent diaphragms of the non-wet joints, no steel bottom plate is provided under the UHPC bridge deck.

[0090] That is, the UHPC composite bridge deck or S-UHPC composite bridge deck to which the present invention is applicable does not require a steel bottom plate to be provided entirely at the bottom of the UHPC bridge deck, but only requires a steel bottom plate to be provided below the wet joint to the adjacent diaphragm.

[0091] The composite beam of the present invention can be any one of a PK composite beam, a fully enclosed steel box composite beam, a double-sided box composite beam, an I-shaped composite beam, and a steel truss composite beam, and has a wide range of applications.

[0092] The above embodiments are only preferred embodiments of the present invention, but cannot be used as limitations of the invention. Any modifications and improvements based on the concept of the present invention should fall within the protection scope of the present invention. The specific protection scope shall be subject to the claims.

Claims

1. A construction method suitable for the rapid construction of UHPC composite beam segments, which is applied to the connection construction of composite beam segments composed of composite bridge decks and steel main beams, wherein the composite bridge deck is composed of at least an upper UHPC bridge deck and a lower bridge deck steel bottom plate, characterized in that: The following steps are involved: S00. Cast the UHPC bridge deck on the steel main beam in one go to form a composite beam segment and steam cure it; S10. The No. 1 composite beam segment is hoisted and after hoisting to the installation position, the position of the composite beam segment is matched and positioned. One No. 1 inclined cable corresponding to the No. 1 composite beam segment is installed, including the tower end hanging cable, the beam end cable insertion and anchoring of the No. 1 inclined cable, and the inclined cable is tensioned. The bridge deck crane is unloaded. After unloading, the weight of the No. 1 composite beam segment is borne by the inclined cable. There are two No. 1 inclined cables, and the two inclined cables are over-tensioned. S20. Lifting the No. 2 composite beam segment, and after lifting it to the installation position, performing position matching and positioning of the composite beam segment; S30. The steel structure of the No. 2 composite beam segment is connected to the steel structure of the No. 1 composite beam segment by T-shaped welding; S40. One No. 2 stay cable corresponding to the No. 2 composite beam segment, including the tower end hanging cable of the No. 2 stay cable, the beam end cable insertion and anchoring, and the cable tensioning, and the bridge deck crane unloading. After unloading, the weight of the No. 2 composite beam segment is borne by the stay cable; S50. The steel structure of the No. 2 composite beam segment is connected to the No. 1 composite beam segment. When the adjacent composite beam segments are connected, the matching parts and the yard plates are first used to match and locate and fix the positions of the two adjacent composite beam segments. Then, the side webs of the steel main beams, the bottom plates of the steel main beams, the middle webs of the steel main beams and the steel bottom plates of the bridge deck at the connection of each composite beam segment are welded to form the circumferential welded seams of the composite beam segments. The circumferential welded seams of the adjacent composite beam segments are welded to form a completed closed steel box through the PBL steel structure patching sections. S60. Two No. 2 inclined cables corresponding to the No. 2 composite beam segment, the two inclined cables are over-tensioned, and three No. 1 inclined cables corresponding to the No. 1 composite beam segment, the three inclined cables are tensioned; S70. Lift the No. 3 composite beam segment, and after lifting it to the installation position, perform position matching and positioning of the composite beam segment; S80. The steel structure of the No. 3 composite beam segment is connected to the steel structure of the No. 2 composite beam segment by T-shaped welding; S90. One No. 3 stay cable corresponding to the No. 3 composite beam segment, including the tower end hanging cable, beam end cable insertion and cable tensioning of the No. 3 stay cable, and the unloading of the bridge deck crane. After unloading, the weight of the No. 3 composite beam segment is borne by the stay cable; S100. The steel structure of the No. 3 composite beam segment is connected to the No. 2 composite beam segment. When the adjacent composite beam segments are connected, the matching parts and the yard plates are first used to match and locate and fix the positions of the two adjacent composite beam segments. Then, the side webs of the steel main beams, the bottom plates of the steel main beams, the middle webs of the steel main beams and the steel bottom plates of the bridge deck at the connection of each composite beam segment are welded to form the circumferential welded seams of the composite beam segments. The circumferential welded seams of the adjacent composite beam segments are welded to form a completed closed steel box through the PBL steel structure patching sections. S110. Wet joint reinforcement connection and casting between composite beam segment No. 1 and composite beam segment No. 2; S120. Two cables No. 3, two cables are over-tensioned, and three cables No. 2, three cables are tensioned; S130. The track jack pushes the whole machine to make the spliced ​​composite beam segment move forward a standard beam segment length; S140. Similarly, referring to step S70 to step S130, install and connect composite beam segments No. 4 to N, and sequentially perform wet joint reinforcement connection and pouring between composite beam segment No. 2 and composite beam segment No. 3, wet joint reinforcement connection and pouring between composite beam segment No. 3 and composite beam segment No. 4, and wet joint reinforcement connection and pouring between composite beam segment No. N and composite beam segment No. N+1, where N is a positive integer, N≥4.

2. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1 is characterized in that: The step S50 and the step S100 both include: inspecting the circumferential welded seams, and after the quality of the welded seams is in good condition, welding the bottom plate stiffening ribs and the side web stiffening ribs of the steel main beam and welding the PBL steel structure patching section.

3. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1 is characterized in that: In the step S00, the casting of the UHPC bridge deck includes the installation of bridge deck reinforcement, embedded sleeves of crash barrier bolts, cable guide tubes, embedded pipes of lighting cables, embedded pipes of temporary hanging points, embedded steel plates of dampers, installation of formwork and roughening-free tape, and casting of UHPC. After casting the UHPC, the film is covered for moisturizing maintenance for about 36 hours. After the UHPC is finally set, the side formwork is removed, and then high-temperature steam curing at 90°C for 48 hours is carried out. After the UHPC is steam cured, the surface of the UHPC bridge deck is covered with geotextile, and watering is continued for moisturizing maintenance for 7 days.

4. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1 is characterized in that: The T-shaped welding connection refers to the welding connection of a T-shaped member composed of the side webs and the flanges on the side webs of two adjacent composite beam segment steel main beams.

5. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1 is characterized in that: The cable force value of each cable is determined by calculation, and it is necessary to balance most of the deadweight of the composite beam segment where the cable is located and to make the joint of the T-shaped welded connection bear less stress.

6. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 5 is characterized in that: The inclined cable needs to be graded and coordinated according to the force, and the bridge crane actively unloads in three stages. When the inclined cable reaches 60% of the cable force, the bridge crane actively unloads 20% of the load; when the inclined cable reaches 80% of the cable force, the bridge crane actively unloads 50% of the load; when the inclined cable reaches 100% of the cable force, the bridge crane actively unloads 100% of the load.

7. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1 is characterized in that: Before pouring the wet joints between adjacent composite beam segments, clean up the debris in the wet joints and fully moisten the UHPC joint surface for no less than 24 hours to ensure that the joints between the wet joints UHPC and the precast panels are tight.

8. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1 is characterized in that: After the pouring and vibration of the wet joints between adjacent composite beam segments are completed, they are manually plastered and covered with a moisturizing film for wet curing. After 48 hours of wet curing, the joints are steam-cured. Steam curing is adopted for the wet joint UHPC, and the steam curing is carried out at a constant temperature of 63℃~68℃ for 72 hours. The steam curing coverage area is larger than the wet joint area, and the wet joint is steam-cured if the width is more than 500 mm around it.

9. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1, characterized in that: The second cable-stayed cable is over-tensioned, and the tensioning force exceeds the theoretical cable force of the cable. Sufficient pre-compression stress is applied at the bridge deck and wet joints to reserve compressive stress for the hoisting of the next section of the composite beam segment. The tensioning force needs to take into account the stress of the bridge deck and the padding of the tensioned end of the cable. It is better if no additional padding is required.

10. The construction method suitable for rapid construction of UHPC composite beam segments according to claim 1, characterized in that: The three tensioning steps of the inclined cables are in the tensioning process. When the wet joint tensile stress meets the allowable stress, the over-tensioned cable force is adjusted to the designed cable force.

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