Design and construction method for multifunctional pushing temporary piers of large-span tied-arch bridge

Abstract

The invention discloses a design and construction method for multifunctional pushing temporary piers of a large-span tied arch bridge, which comprises the following steps of: symmetrically arranging temporary piers at the upstream and downstream of a main beam, and respectively arranging two walking jacks at the top of each temporary pier; in the main beam pushing stage, the two sides of the top end of the temporary pier are each provided with an end supporting base, the end supporting bases and the walking type jacks work cooperatively in a reciprocating mode, the four transverse walking type jacks actively and synchronously push the main beam, and longitudinal pushing operation of the main beam is completed; before arch ribs are assembled, a main beam is integrally jacked through a walking type jack, then end supporting seats arranged on the two sides of the top end of a temporary pier are replaced with middle supporting seats arranged in the middle of the top end of the temporary pier, and the main beam and an upper structure of the main beam are supported by the middle supporting seats. According to the design and construction method for the temporary piers, the temporary piers can continuously keep the supporting balance state for the ultra-wide main beam in the main beam pushing and main arch assembling stages, and transverse stress unbalance loading is avoided.

Description

Technical Field

[0001] This invention relates to the field of bridge jacking construction technology, and in particular to a design and construction method for a multifunctional temporary pier for jacking a long-span tied arch bridge. Background Technology

[0002] Long-span simply supported tied arch bridges have achieved significant development due to their excellent landscape effects, rational structural stress distribution, and good terrain adaptability. Because of their structural stress characteristics, simply supported tied arch bridges are generally constructed using a method of first jacking up the main girder and then assembling the main arch on top of it. This construction method is characterized by a typical two-stage construction process: jacking up the main girder and assembling the main arch.

[0003] In recent years, with the rapid development of transportation demand, the spans and deck widths of simply supported tied arch bridges have become increasingly larger. This has led to a surge in the number of temporary piers and the loads they bear. Simultaneously, issues such as lateral load imbalance and instability of the ultra-wide main girder under temporary pier support have become increasingly prominent. For large-span simply supported tied arch bridges with ultra-wide main girders, temporary piers have become a significant constraint on the structural safety during construction. Therefore, to overcome the shortcomings of existing technologies, there is an urgent need for a design and construction method for temporary piers that can maintain a continuous and balanced support for the ultra-wide main girder during the main girder jacking and main arch assembly stages, thus preventing lateral load imbalance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a temporary pier design and construction method that can maintain the supporting balance of the ultra-wide main beam during the main beam jacking and main arch assembly stages, and avoid lateral force eccentricity.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] A design and construction method for a multifunctional incremental launching temporary pier for a long-span tied arch bridge, comprising the following steps:

[0007] (1) Temporary piers are symmetrically arranged at the upstream and downstream of the main beam, and two walking jacks are installed on the top of each temporary pier.

[0008] (2) During the main beam jacking stage, end support seats are set on both sides of the top of the temporary pier. The end support seats work in coordination with the walking jacks. Four walking jacks in the transverse direction actively and synchronously jack the main beam to complete the longitudinal jacking operation of the main beam.

[0009] (3) Before the arch rib is assembled, the main beam is lifted as a whole by walking jacks, and then the end support seats set on both sides of the top of the temporary pier are replaced with the middle support seats set in the middle of the top of the temporary pier. The middle support seats support the main beam and its superstructure.

[0010] Furthermore, the temporary pier in step (1) includes multiple columns arranged in a matrix and supported on the foundation. The top of each column is symmetrically provided with a column top distribution beam. A pair of jacking longitudinal beams are symmetrically provided on the top surface of the column top distribution beams. The jacking longitudinal beams are perpendicular to the column top distribution beams. A pair of transverse flat beams are symmetrically provided on the top surface of the jacking longitudinal beams. The transverse flat beams are perpendicular to the jacking longitudinal beams. The walking jacks are all provided on each jacking longitudinal beam.

[0011] Furthermore, the end support is located on the side of the transverse spreader beam, and the middle support is located in the middle of the transverse spreader beam.

[0012] Furthermore, the bottom of the transverse flat beam has a downward trapezoidal protrusion.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention employs two different stress states for the temporary piers during the main beam jacking and main arch assembly. During jacking, the top surfaces of the temporary piers upstream and downstream of the main beam are supported by four end supports on the top of the transverse spreader beam. During main arch assembly, the top surfaces of the temporary piers upstream and downstream of the main beam are supported by two central supports on the top of the transverse spreader beam. Throughout the process, the temporary piers remain centrally stressed, preventing lateral load instability and improving material utilization, thus effectively saving on construction materials. In the jacking and assembly of ultra-wide main beams, the invention fully considers the limitations of on-site construction conditions and the capabilities of the walking jacks, effectively avoiding the development and investment in large equipment, preventing waste, and promoting energy conservation and environmental protection. Attached Figure Description

[0015] Figure 1 This is a front view of the temporary pier in this invention;

[0016] Figure 2 This is a side view of the temporary pier in this invention;

[0017] Figure 3 This is a schematic diagram of the main beam in the jacking stage of the present invention;

[0018] Figure 4 This is a longitudinal schematic diagram of the main beam during the jacking stage of the present invention;

[0019] Figure 5 This is a schematic diagram of the main beam in the main arch assembly stage of the present invention;

[0020] Figure 6 This is a longitudinal schematic diagram of the main beam during the main arch assembly stage of the present invention;

[0021] Figure 7This is a diagram showing the distribution of the stress support points of the temporary pier in this invention.

[0022] Figure label:

[0023] 1-Main beam, 2-Temporary pier, 3-Column, 4-Column top distribution beam, 5-Pushing longitudinal beam, 6-Transverse spreader beam, 7-Walking jack, 8-End support seat, 9-Middle support seat. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] like Figures 1 to 6 As shown, a design and construction method for a multifunctional jacking temporary pier for a long-span tied arch bridge is described, with the following steps:

[0026] (1) To ensure the lateral stability of the main beam 1 during the jacking process, temporary piers 2 are symmetrically arranged upstream and downstream of the main beam 1. For example... Figure 1 and Figure 2 As shown, the temporary pier 2 includes multiple columns 3 arranged in a matrix and supported on the foundation. A column top distribution beam 4 is symmetrically arranged on the top of each column 3. A pair of jacking longitudinal beams 5 are symmetrically arranged on the top surface of each column top distribution beam 4, perpendicular to the column top distribution beam 4. A pair of transverse spreader beams 6 are symmetrically arranged on the top surface of each jacking longitudinal beam 5, perpendicular to the jacking longitudinal beams 5. Since the existing jacking equipment cannot meet the requirements for jacking the ultra-wide main beam with its heavy weight, a walking jack 7 needs to be installed on each jacking longitudinal beam 5 of the upstream and downstream temporary piers 2 in the transverse direction.

[0027] (2) such as Figure 3 and Figure 4 As shown, during the jacking stage of the main beam 1, an end support seat 8 is set on both sides of each transverse spreader beam 6, and the top of each temporary pier 2 has four end support seats 8. The end support seats 8 work in coordination with the walking jacks 7, and the four transverse walking jacks 7 actively and synchronously jack the main beam 5 to complete the longitudinal jacking operation of the main beam 1.

[0028] (3) After the main beam 1 is pushed out, since two walking jacks 7 are installed on the upstream and downstream temporary piers 2, if the beam continues to be stressed according to the four transverse support points, it will form a structure similar to a three-span continuous beam. Figure 7As shown, when a single temporary pier 2 has four end supports 8, the stress points are A, B, C, and D. As the span load continues to increase, the middle span of the main beam 1 deflects downwards, and the side supports on both sides show an upward trend. That is, the end supports 8 at points C and D of the left temporary pier 2 and points A and B of the right temporary pier 2 show an upward trend. This leads to an increase in the stress on the two inner supports, namely, the stress on the end supports 8 at points A and B of the left temporary pier 2 and points C and D of the right temporary pier 2. This inevitably results in a situation where the stress on the outer supports decreases while the stress on the inner supports increases, causing uneven stress on the temporary pier 2 and significant eccentricity in the stress distribution, seriously affecting the structural safety of the temporary pier 2.

[0029] like Figure 5 and Figure 6 As shown, before assembling the arch rib, the main beam 1 is lifted as a whole using walking jacks 7. Then, the end supports 8 set on both sides of the top of the transverse spreader beam 6 are replaced with the middle support 9 set in the middle of the top of the transverse spreader beam 6. The middle support 9 supports the main beam 1 and its superstructure. Figure 7 E and F in the fulcrum.

[0030] During the subsequent arch rib assembly stage, as the load increases, temporary pier 2 will always maintain a centrally loaded state to support the main beam 1 and its superstructure. This ensures that throughout the construction of the main beam 1 and the main arch, the columns 3 of temporary pier 2 are evenly loaded and the load is fully distributed. This not only avoids lateral load instability of temporary pier 2 but also improves the material utilization rate of temporary pier 2, effectively saving on the amount of construction materials used. In the jacking assembly of the ultra-wide main beam, the limitations of on-site construction conditions and the capacity limitations of the walking jack 7 were fully considered, effectively avoiding the development and investment of large-scale equipment, avoiding waste, and promoting energy conservation and environmental protection.

[0031] The bottom of the transverse spreading beam 6 has a downward trapezoidal protrusion. The trapezoidal protrusion thickens the middle of the transverse spreading beam 6, thereby increasing the structural strength of the transverse spreading beam 6 and relatively reducing its height.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design and construction method for a multifunctional incremental launching temporary pier for a long-span tied arch bridge, characterized in that: The steps are as follows: (1) Temporary piers (2) are symmetrically arranged on the upstream and downstream sides of the main beam (1), and two walking jacks (7) are set on the top of each temporary pier (2). (2) During the jacking stage of the main beam (1), end support seats (8) are set on both sides of the top of the temporary pier (2). The end support seats (8) and the walking jacks (7) work together in reciprocating motion. The four walking jacks (7) actively and synchronously jack the main beam (1) to complete the longitudinal jacking operation of the main beam (1). (3) Before the arch rib is assembled, the main beam (1) is lifted as a whole by walking jacks (7), and then the end support seats (8) set on both sides of the top of the temporary pier (2) are replaced with the middle support seat (9) set in the middle of the top of the temporary pier (2), and the middle support seat (9) supports the main beam (1) and its superstructure.

2. The design and construction method for a multifunctional jacking temporary pier for a long-span tied arch bridge according to claim 1, characterized in that: The temporary pier (2) in step (1) includes multiple columns (3) arranged in a matrix and supported on the foundation. The top of the column (3) is symmetrically provided with a column top distribution beam (4). The top surface of the column top distribution beam (4) is symmetrically provided with a pair of jacking longitudinal beams (5). The jacking longitudinal beams (5) are perpendicular to the column top distribution beam (4). The top surface of the jacking longitudinal beams (5) is symmetrically provided with a pair of transverse flat beams (6). The transverse flat beams (6) are perpendicular to the jacking longitudinal beams (5). The walking jacks (7) are all provided on each jacking longitudinal beam (5).

3. The design and construction method for a multifunctional jacking temporary pier for a long-span tied arch bridge according to claim 2, characterized in that: The end support (8) is located on the side of the transverse flat beam (6), and the middle support (9) is located in the middle of the transverse flat beam (6).

4. The design and construction method for a multifunctional jacking temporary pier for a long-span tied arch bridge according to claim 3, characterized in that: The bottom of the transverse flat beam (6) has a downward trapezoidal protrusion.

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