UHPC (Ultra High Performance Concrete) box-type section cover beam gate-type pier

Abstract

The invention relates to the technical field of bridge construction, in particular to a UHPC box-type section cover beam gate-type pier which comprises a plurality of UHPC prefabricated box beam sections and stand columns, the UHPC prefabricated box beam sections are longitudinally connected and connected through tensioning internal prestressing tendons to form a UHPC box-type section cover beam, the UHPC box-type section cover beam is erected on the stand columns, and the UHPC box-type section cover beam gate-type pier is arranged on the stand columns. Pre-embedded sleeves are arranged in the UHPC prefabricated box beam sections, reserved steel bars of the stand columns are connected with the pre-embedded sleeves, and the UHPC box-type section cover beam and the stand columns are connected into an integral structure by pouring beam end post-pouring section concrete. The bent cap has the advantages that the bent cap has very high practicability, based on the ultrahigh mechanical property and durability of the UHPC material, the box-shaped section is adopted, so that the problems that a common concrete bent cap is limited in overall construction weight and poor in durability are solved, and the problems that a steel bent cap is difficult to maintain and high in manufacturing cost are solved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a UHPC box-section cap beam portal pier. Background Art

[0002] With the increasing traffic volume and the continuous improvement of the requirements for bridge service performance, traditional concrete portal piers can no longer meet the high standards of modern bridge engineering in terms of bearing capacity, durability and seismic resistance.

[0003] Traditional concrete portal piers have exposed many limitations in long-term practice. First, the material's own strength is relatively limited. In order to meet the design bearing capacity requirements, a larger cross-sectional size is often required, which directly leads to the problem of excessive structural deadweight. The larger deadweight not only increases the cost and difficulty of infrastructure construction, but also generates a larger inertial force under the action of dynamic loads such as earthquakes, which has an adverse effect on the seismic performance of the structure and increases the risk of damage to the bridge in earthquake disasters. Secondly, in terms of durability, ordinary concrete is easily corroded by environmental factors, which seriously reduces the durability and service life of the structure. Summary of the invention

[0004] The purpose of the present invention is to provide a UHPC box-section cap beam portal pier based on the above-mentioned deficiencies in the prior art. By assembling the UHPC box-section cap beam and coordinating the connection with the columns, the problem that ordinary concrete spans have a large deadweight and cannot be hoisted for construction is solved. At the same time, the limitations of poor structural bearing capacity and durability are solved and the span of the portal pier is increased.

[0005] The purpose of the present invention is achieved by the following technical solutions: A UHPC box-section cap beam portal pier, characterized in that it comprises a plurality of UHPC prefabricated box beam segments and columns, wherein the plurality of UHPC prefabricated box beam segments are longitudinally connected and connected through prestressed beams in tension bodies to form a UHPC box-section cap beam, the UHPC box-section cap beam is erected on the columns, embedded sleeves are arranged in the UHPC prefabricated box beam segments, reserved steel bars of the columns are connected to the embedded sleeves, and the UHPC box-section cap beam and the columns are connected into an integral structure by pouring concrete of a post-cast section at the beam end.

[0006] The UHPC box-section cap beam further includes a plurality of UHPC diaphragms, which are arranged in the UHPC prefabricated box beam segments and cast together.

[0007] The UHPC prefabricated box girder segment is additionally provided with an external prestressed tendon.

[0008] The external prestressed tendons are connected and tensioned by setting a steering block.

[0009] The UHPC prefabricated box beam segments are longitudinally connected by adhesive joints and shear keys.

[0010] The advantages of the present invention are: it is highly practical. Based on the ultra-high mechanical properties and durability of UHPC materials, the box-type section not only solves the problem of limited overall construction weight and poor durability of ordinary concrete cap beams, but also solves the problem of difficult maintenance and high cost of steel cap beams. At the same time, based on the excellent material properties of UHPC, it is applied to the design and construction of box-section cap beam portal piers, which is expected to break through the technical bottleneck of traditional portal piers, achieve a comprehensive improvement in the performance of the bridge substructure, and meet the urgent needs of modern transportation infrastructure construction for high-performance and long-life bridge structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a cross-sectional view of the cap beam of the present invention; Figure 2 The cross section of the cap beam of the present invention is Figure I ; Figure 3 The cross section of the cap beam of the present invention is Figure II ; Figure 4 It is a side view of the portal pier of the present invention; Figure 5 It is the front view of the portal pier of the present invention; Figure 6 It is a schematic diagram of the prestressed steering block of the present invention. DETAILED DESCRIPTION

[0012] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art: like Figure 1-6 As shown, the reference numerals in the figure respectively represent: UHPC prefabricated box girder segment 1, UHPC diaphragm 2, portal pier column 3, internal prestressed tendon 4, external prestressed tendon 5, cushion stone 6, adhesive joint 7, post-cast section concrete 8, turning block 9, anchor end 10.

[0013] Example: Combination Figures 1 to 6 As shown, the UHPC box-section cap beam portal pier in this embodiment includes the following process when implemented: First, the UHPC prefabricated box girder segment 1 is prefabricated in the factory, transported to the construction site, and longitudinally connected using adhesive joints 7 and corresponding shear keys such as pins or serrated blocks to assemble the UHPC box-section cap beam; the internal prestressed tendons 4 are tensioned and anchored before the structure is hoisted as a whole. After it is hoisted onto the portal pier column 3, the post-cast concrete 8 is poured at the end of the cap beam, and the steering block 9 is installed. After the post-cast concrete 8 reaches the required design strength, the external prestressed tendons 5 are tensioned and anchored.

[0014] In this embodiment, the UHPC box-section cap beam is composed of a plurality of UHPC prefabricated box beam segments 1 and a plurality of UHPC diaphragms 2, and the diaphragms 3 are cast together with the UHPC box beam segments 1 in the factory.

[0015] The UHPC box-section cap beam is a prestressed structure. After being assembled into an integral structure, the prestress of 4 is tensioned inside the body and anchored. In combination with the actual situation, relevant stabilization measures are taken before construction to prevent excessive prestressing, which may lead to instability.

[0016] When pouring the portal pier column 3 at the bridge construction site, steel bars are reserved at the pile top position of the portal pier column 3. After the UHPC box-section cap beam is hoisted to the top surface of the portal pier column 3, the reserved steel bars are connected to the embedded sleeves buried in the UHPC prefabricated box beam segment 1, and corresponding measures are taken for temporary stabilization.

[0017] Cast the post-cast section concrete 8 at the end of the UHPC box-section cap beam, where the height of the post-cast section concrete 8 should be higher than the reserved steel bar length at the top of the portal pier column 3 to ensure that the structural anchorage length meets the requirements. The next process can be carried out only after the strength and elastic modulus of the post-cast section concrete 8 meet the design requirements.

[0018] In this embodiment, the UHPC box-section cap beam is a prestressed component, and the specific distribution of the beams should be determined according to the specific calculation conditions to determine whether to use the external prestressed beam 5. If the external prestressed beam 5 is used, it is necessary to set the turning block 9 and use the post-casting section concrete 8 to tension the external prestressed beam 5, and then seal the anchor end 10 after completion.

[0019] The portal pier column 3 as the lower structure should be used for the upper simply supported beam and continuous beam construction, and the support pad stone 6 should be used for connection. The support pad stone 6 should be constructed simultaneously with the UHPC prefabricated box beam segment 1 in the factory. The position of the support pad stone 6 should be marked and constructed according to the actual situation on site.

[0020] In addition to the above-mentioned segmental prefabrication, assembly and hoisting construction, UHPC box-section cap beams can also be constructed using integral prefabrication or integral cast-in-place construction methods.

[0021] After completing the above construction steps, the simply supported beam is hoisted or the continuous beam is constructed.

[0022] During construction, the following steps may be included: prefabrication of UHPC box girder segments 1, diaphragms 2, and cushion stones 6 in the factory → after the construction of portal pier columns 3 is completed, the prefabricated components are transported to the site and assembled through adhesive joints 7 and shear keys → tensioning of internal prestressed tendons 4 → integral lifting of the UHPC box-section cap beam to the top of the portal pier columns 3 → pouring of post-cast section concrete 8, and waiting for the structure to form a consolidation system → installation of steering blocks 9 → tensioning of external prestressed tendons 5, and sealing of anchor ends 10.

[0023] Although the above embodiments have described in detail the concepts and embodiments of the present invention with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and changes can still be made to the present invention without departing from the scope of the claims, so they are not described one by one here.

Claims

1. A UHPC box-section cap beam portal pier, characterized in that: It comprises a plurality of UHPC prefabricated box beam segments and columns. The plurality of UHPC prefabricated box beam segments are longitudinally connected and connected through prestressed tendons in the tension body to form a UHPC box-section cap beam. The UHPC box-section cap beam is erected on the column. An embedded sleeve is arranged in the UHPC prefabricated box beam segment. The reserved steel bars of the column are connected to the embedded sleeve. The UHPC box-section cap beam and the column are connected into an integral structure by pouring concrete of the post-cast section at the beam end.

2. A UHPC box-section cap beam portal pier according to claim 1, characterized in that: The UHPC box-section cap beam further includes a plurality of UHPC diaphragms, which are disposed in the UHPC prefabricated box beam segments and cast together.

3. The UHPC box-section cap beam portal pier according to claim 1, characterized in that: The UHPC prefabricated box girder segment is additionally provided with an external prestressed tendon.

4. A UHPC box-section cap beam portal pier according to claim 3, characterized in that: The external prestressed tendons are connected and tensioned by setting a steering block.

5. The UHPC box-section cap beam portal pier according to claim 1, characterized in that: The UHPC prefabricated box beam segments are longitudinally connected by adhesive joints and shear keys.

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