Method for reinforcing horizontal cracks in upper middle of solar heat absorption tower and solar heat absorption tower

Abstract

The invention belongs to the technical field of anti-seismic design of high-rise structures, and provides a method for reinforcing horizontal cracks in the middle-upper portion of a solar heat absorption tower and the solar heat absorption tower. The method comprises the steps that the height of a concrete cylinder in the heat absorption tower is determined, and a profile steel reinforced concrete section is determined at the preset position of the middle-upper portion of the concrete cylinder according to the height; a plurality of pieces of H-shaped steel are arranged in the circumferential direction of the section steel reinforced concrete section; for an area without a leading direction of wind load, the H-shaped steel is uniformly arranged in the circumferential direction of the concrete barrel, and the circumferential distance between the adjacent H-shaped steel is determined according to an earthquake acceleration value; for an area with the prevailing wind direction, the H-shaped steel is non-uniformly arranged in the circumferential direction of the concrete barrel, and directional correction is conducted on the circumferential distance according to the prevailing wind direction; and when the reinforcing position, the layout form and the number of the H-shaped steel are determined, the structural characteristics, the stress condition and the field wind load condition of the heat absorption tower are comprehensively considered, and the problem of too high cost is avoided on the basis of ensuring the reinforcing effect.

Description

Technical Field

[0001] This invention belongs to the field of seismic design technology for tall structures, and particularly relates to a method for reinforcing horizontal cracks in the upper part of a solar heat absorption tower and the solar heat absorption tower itself. Background Technology

[0002] Tall solar heat absorption towers have a relatively flexible concrete structure, making them more sensitive to vertical seismic forces. This makes them prone to the appearance and expansion of horizontal cracks. Compared to other buildings, they lack multiple seismic defenses and are easily damaged or even collapse under strong earthquakes.

[0003] Existing measures to prevent the generation and development of horizontal cracks in solar heat absorption towers mainly include increasing the strength grade or reinforcement ratio of concrete, reinforcing with steel plates or carbon fiber, and increasing the cross-sectional thickness. These methods increase the risk of brittle fracture and material costs. High-altitude construction is difficult and significantly increases the self-weight of the structure. They do not take into account the structural characteristics, stress conditions, and wind load conditions of the heat absorption tower itself, resulting in a contradiction between reinforcement effectiveness and cost. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a method for reinforcing horizontal cracks in the upper part of a solar heat-absorbing tower, as well as the solar heat-absorbing tower itself. When determining the location, layout, and quantity of H-beams for reinforcement, the invention comprehensively considers the structural characteristics of the heat-absorbing tower, its stress conditions, and the on-site wind load conditions, thus ensuring the reinforcement effect while avoiding excessive costs.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a method for reinforcing horizontal cracks in the upper part of a solar heat absorption tower, employing the following technical solution: A method for reinforcing horizontal cracks in the upper part of a solar heat absorption tower includes: Determine the height of the concrete cylinder in the heat absorption tower, and determine the steel reinforced concrete section at a predetermined position in the upper part of the concrete cylinder based on the height; Multiple H-beams are installed circumferentially in the steel reinforced concrete section; For areas where there is no dominant wind load direction, H-beams are uniformly arranged around the circumference of the concrete cylinder, and the circumferential spacing between adjacent H-beams is determined based on the seismic acceleration value; for areas with a dominant wind direction, H-beams are non-uniformly arranged around the circumference of the concrete cylinder, and the circumferential spacing is directionally corrected according to the dominant wind direction.

[0006] Furthermore, the directional correction of the circumferential spacing based on the prevailing wind direction includes: determining the prevailing wind direction; dividing the perimeter of the concrete cylinder into four regions using the prevailing wind direction and its perpendicular direction as axes; reducing the circumferential spacing in the regions on both sides of the concrete cylinder perpendicular to the prevailing wind direction; and increasing the circumferential spacing in the regions on both sides of the concrete cylinder parallel to the prevailing wind direction.

[0007] Furthermore, the circumferential spacing between adjacent H-beams is determined based on the seismic acceleration value. For areas where the design seismic acceleration value is not less than a preset value, the circumferential spacing tends towards the preset lower limit; otherwise, the circumferential spacing tends towards the preset upper limit.

[0008] Furthermore, the steel-reinforced concrete section is provided with longitudinal and circumferential reinforcing bars; the H-beam is fixed to the concrete within the steel-reinforced concrete section by H-beam flange shear studs and H-beam web shear studs.

[0009] Furthermore, the steel-reinforced concrete section is provided with a transition section, in which the circumferential reinforcement gradually changes from sparse to dense.

[0010] Furthermore, the transition section is located between the reinforced concrete section and the steel reinforced concrete section of the concrete cylinder.

[0011] Furthermore, the height range of the transition section between the reinforced concrete section and the steel reinforced concrete section is 0.60H to 0.62H of the total height H of the concrete cylinder.

[0012] Furthermore, the center of the steel-reinforced concrete section is located at 2 / 3 of the total height of the concrete cylinder.

[0013] To achieve the above objectives, in a second aspect, the present invention also provides a solar heat absorption tower, which adopts the following technical solution: A solar heat absorption tower is obtained by a method for reinforcing the upper horizontal cracks of a solar heat absorption tower as described in the first aspect; it includes a plurality of H-beams arranged circumferentially in a steel reinforced concrete section.

[0014] Furthermore, the steel-reinforced concrete section is provided with longitudinal and circumferential reinforcing bars; the H-beam is fixed to the concrete within the steel-reinforced concrete section by H-beam flange shear studs and H-beam web shear studs.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention reinforces weak areas of the pre-set height reinforced concrete section of the concrete cylinder with H-beams, avoiding the problem of horizontal cracks caused by vertical seismic forces. Furthermore, in areas where wind load has no dominant direction, the H-beams are uniformly arranged circumferentially around the concrete cylinder, with the circumferential spacing between adjacent H-beams determined based on the seismic acceleration value. In areas with a dominant wind direction, the H-beams are non-uniformly arranged circumferentially around the concrete cylinder, and the circumferential spacing is directionally corrected according to the dominant wind direction. The determination of the H-beam reinforcement location, layout, and quantity comprehensively considers the structural characteristics of the heat absorption tower itself, its stress conditions, and the on-site wind load conditions, ensuring reinforcement effectiveness while avoiding excessive costs. Attached Figure Description

[0016] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0017] Figure 1 This is a schematic diagram of the structure of a tall solar heat absorption tower according to an embodiment of the present invention; Figure 2 This is a plan view of the SRC segment according to an embodiment of the present invention; Figure 3 This is a horizontal cross-sectional view of the SRC segment according to an embodiment of the present invention; Figure 4 This is a vertical cross-sectional view of the SRC segment according to an embodiment of the present invention; Among them, 1. H-beams; 2. Concrete cylinder; 3. Longitudinal reinforcement; 4. Circumferential reinforcement; 5. Tie bars; 6. H-beam flange shear studs; 7. H-beam web shear studs. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0020] Solar energy, as a prominent and sustainable clean energy source, plays a crucial role in addressing the looming global energy crisis. Concentrated Solar Power (CSP) has garnered widespread attention due to its ability to mitigate the inherent intermittency of solar resources. Among various forms of concentrated solar power (CSP) technologies, Solar Power Tower (SPT) systems have become globally recognized and widely adopted due to their superior power generation efficiency, cost-effectiveness, and commercial viability. The core of an SPT system is the receiver tower, the cornerstone structure supporting the receiver, constructed from either concrete or steel. Concrete structures are particularly popular due to their cost-effectiveness, especially in tall towers. Unlike traditional concrete chimneys, the unique design of a solar power tower features a large-mass molten salt receiver mounted on its top.

[0021] Compared to ordinary buildings, this type of structure is simple in form and inconvenient to repair and maintain. Due to design and construction issues during the construction period, as well as the effects of various adverse factors such as natural disasters and environmental erosion during long-term use, existing tall concrete structures generally suffer from cracking and severe concrete carbonation, resulting in a decline in structural safety and reliability.

[0022] Tall concrete structures are highly flexible and sensitive to vertical seismic forces, making them prone to the appearance and expansion of horizontal cracks. Compared with other buildings, they lack multiple seismic defenses and are easily damaged or even collapsed under strong earthquakes, resulting in serious economic losses.

[0023] Existing measures to prevent the generation and development of horizontal cracks mainly include the following three aspects: increasing the strength grade or reinforcement ratio of concrete. Although this method can improve seismic resistance to a certain extent, it increases the risk of brittle failure and increases material costs; external steel plate or carbon fiber reinforcement. This method is generally used to reinforce the structure after an earthquake. High-altitude construction is difficult, and carbon fiber has poor heat resistance; increasing the cross-sectional thickness. This method will significantly increase the self-weight of the structure. Since there is a large mass molten salt tank on the upper part of the heat absorption tower structure, the vertical seismic effect of the structure will be further amplified, leading to a further increase in design costs.

[0024] To address at least one of the aforementioned problems, one embodiment of the present invention provides a method for reinforcing horizontal cracks in the upper part of a solar heat-absorbing tower. Analysis of the stress distribution of a typical tall heat-absorbing tower under rare vertical earthquakes revealed that the upper part of the tower body, approximately 2 / 3H, is a weak area prone to horizontal cracks under such conditions. This method involves adding a local steel-reinforced concrete section in the upper part of the tower body. Specifically, vertical steel is added at 2 / 3 of the tower's height, sharing the load with existing steel reinforcement and concrete to form a composite stress system with high stiffness and ductility. This location is precisely where tall structures are most susceptible to horizontal cracks under vertical earthquakes. Adding a steel-reinforced concrete section at this location not only significantly improves the axial bearing capacity of this area and reduces the alternating tensile and compressive failure caused by the amplification effect of vertical earthquake acceleration, but also effectively suppresses the generation and development of horizontal cracks, thereby improving the overall seismic performance of the structure. Furthermore, a scientific, systematic, and economical method for determining the circumferential spacing s of the steel sections is proposed. This method optimizes and balances multiple influencing factors to ultimately select the optimal circumferential spacing s. s= 0.08 D ~0.12 D This range allows for precise determination of the quantity of structural steel. n This achieves a perfect balance between safety, economy, and ease of construction.

[0025] One embodiment of the present invention, such as Figure 2 and Figure 3 As shown, a solar thermal absorption tower is also provided, comprising a concrete cylinder 2 and a steel reinforced concrete section (SRC section) arranged in the upper part of the concrete cylinder 2; the height of the concrete cylinder 2 is... H The center position of the steel reinforced concrete section (SRC section) is set at the total height of the cylinder. H At 2 / 3 of the height, the height of the steel reinforced concrete section (SRC section) is equal to the total height of the concrete cylinder 2. H1 / 10; The steel reinforced concrete section (SRC section) includes several H-beams 1, circumferential reinforcing bars 4, longitudinal reinforcing bars 3, and concrete arranged vertically along the concrete cylinder 2. The H-beams 1 are reliably connected to the concrete through shear connectors (H-beam flange shear studs 6 and H-beam web shear studs 7) and share the force with the original longitudinal reinforcing bars 3 in the concrete cylinder 2; tie bars 5 are provided between the longitudinal reinforcing bars 3 on the inner wall and the longitudinal reinforcing bars 3 on the outer wall of the concrete cylinder 2; the circumferential stirrups 4 are in the SRC section. Within section C, the stirrups are densely arranged with a spacing smaller than that in the conventional area of ​​the cylinder. The SRC section includes a transition section where the circumferential reinforcement 4 gradually changes from sparse to dense, achieving a smooth transition in stiffness between the reinforced concrete section (RC section) and the steel-reinforced concrete section (SRC section). Under vertical seismic loading, the SRC section enhances the axial stiffness and load-bearing capacity of the upper part of the cylinder, suppressing horizontal cracks at 2 / 3 of its height and preventing crack propagation and penetration, thereby improving the overall seismic performance of the structure. Finite element analysis comparison reveals that, compared to conventional heat absorption tower structures, the configuration of this invention can reduce the peak tensile stress in weak parts of the cylinder by more than 20% and increase energy dissipation capacity by more than 25% under rare vertical seismic loading.

[0026] The height range of the steel reinforced concrete section (SRC section) is 0.62 times the total height of the concrete cylinder 2. H～ 0.72 H The area covered by the horizontal cracks in the cylinder under rare vertical earthquake action.

[0027] The height of the steel reinforced concrete section (SRC section) is 0.1 times the total height of the concrete cylinder 2. H .

[0028] The height range of the transition section between the reinforced concrete section (RC section) and the steel reinforced concrete section (SRC section) is 0.60% of the total height of the concrete cylinder 2. H ~0.62 H .

[0029] The requirements for the vertical H-beam 1 section in the reinforced concrete section (RC section) are as follows: the web thickness and flange thickness should meet the local buckling requirements. Wide flange H-beam section (HW) and medium flange section (HM) are preferred. The strong axis is arranged circumferentially along the cylinder wall to achieve similar stable bearing capacity around the two main axes under compression.

[0030] The number of H-beams 1 in the reinforced concrete section (RC section) n Based on the outer circumference of the cylinder and the circumferential spacing s Sure, n= π D / s Optionally, the circumferential spacings The value range is 0.08. D ~0.12 D ; D This refers to the diameter of the SRC section of the cylindrical shell. This range is an optimized interval determined by balancing structural performance, construction feasibility, and economy.

[0031] The circumferential spacing s The value of is no greater than 0.12. D Its main purpose is to ensure the integrity of the SRC section, prevent stress concentration and local crushing of concrete due to excessive spacing between steel sections, and meet the requirements of local stability of the steel sections themselves.

[0032] The circumferential spacing s The value is not less than 0.08 D Its main purpose is to ensure that there is sufficient clearance between adjacent steel flanges, so as to ensure that the concrete is poured densely, avoid construction difficulties, and control the amount of steel used within an economically reasonable range.

[0033] The circumferential spacing s The value of is the same as the design basic seismic acceleration value ( a This involves linkage. Specifically, it involves the design basic seismic acceleration value. a Areas with ≥0.20g, s The value of should tend towards the lower limit, i.e., 0.08. D ~0.010 D This is because the combination of high-intensity earthquakes and weak sites significantly amplifies the dynamic response of the structure. Therefore, it is necessary to maximize the axial stiffness and tensile bearing capacity of the SRC segment through reinforced steel sections to effectively suppress crack formation. Conversely, for the design basic seismic acceleration value... a Areas with <0.20g, s The value of can approach the upper limit, namely 0.10. D ~0.12 D Under these conditions, the seismic force is relatively weak. By appropriately widening the spacing between steel sections, optimal economic benefits can be achieved while ensuring structural safety and controlling crack width. This dynamic design method ensures the scientific validity, universality, and engineering applicability of this invention.

[0034] The arrangement of H-beams 1 within the SRC section can be either uniformly arranged circumferentially along the cylinder wall or non-uniformly arranged.

[0035] The circumferential arrangement strategy of the H-beams 1 needs to be optimized based on the wind load characteristics of the project site. Specifically, it can be divided into the following two cases: In the first scenario, for areas where wind load has no significant dominant direction or wind-induced vibration is not controlled, the H-beams 1 are evenly distributed along the circumference of the concrete cylinder. In this case, the circumferential spacing...s The value range is 0.08. D ~0.12 D .

[0036] In the second scenario, for areas with prevailing winds, to improve material utilization efficiency and structural performance, the H-beams 1 are arranged non-uniformly, meaning the circumferential spacing is adjusted. s Directional correction is performed. The specific method is as follows: ① Determine the prevailing wind direction; ② Divide the circumference of the cylinder into four regions using the prevailing wind direction and its perpendicular direction as axes; ③ Adjust the circumferential spacing in the regions perpendicular to the prevailing wind direction on both sides of the cylinder (i.e., the windward and leeward sides). s To reduce the stiffness and crack resistance of this area, a reduction correction was made by using a denser steel frame arrangement; in the areas on both sides of the cylinder parallel to the prevailing wind direction, the circumferential spacing was adjusted. s The size was increased and modified to accommodate sparse steel sections.

[0037] The circumferential spacing s of the steel sections in the dense steel section arrangement area is corrected to 0.85. s ~0.9 s The circumferential spacing s of the steel sections in the sparse steel section arrangement area is corrected to 1.1. s ~1.15 s A transition zone should be set between areas with different arrangement densities to allow the spacing between the steel sections to change gradually, in order to avoid stress concentration caused by abrupt changes in stiffness.

[0038] The shear connector is a stud, with a longitudinal spacing of... a v ≤8 d s and a v ≤300mm, d s Take 12-16mm, where d s The diameter of the connector. The spacing of the stirrups within the steel-reinforced concrete section. s h ≤0.5 d c And not exceeding 100mm, gradually widening within the transition zone. d c The thickness of the SRC section cylinder. The diameter of the longitudinal reinforcing bars is 16-20mm, and the diameter of the circumferential reinforcing bars is 12-16mm. The H-beams are made of Q235 steel. The reinforcing bars are HPB30, and cold drawing is not permitted for any of the reinforcing bars.

[0039] This invention significantly improves crack resistance by incorporating a steel-reinforced concrete (SRC) section in the upper part of the tower, thereby significantly enhancing the structure's vertical seismic resistance. In the SRC section, the vertical tensile stress is shared by both the structural steel and the reinforcing steel, achieving a rational load distribution. The synergistic effect of the reinforcing steel and the structural steel effectively suppresses the generation and development of horizontal cracks in the upper part of the tower, reducing the peak vertical tensile stress in the upper part of the tower by more than 20%, effectively controlling the generation of horizontal cracks, and significantly improving the overall structural integrity.

[0040] The introduction of structural steel in the SRC section of this invention provides the structure with additional deformation capacity, enabling it to undergo a large range of elastoplastic deformation without brittle failure under dynamic forces such as vertical earthquakes. This design significantly improves the structure's ductility and energy dissipation capacity, increasing energy dissipation by more than 25%, effectively absorbing seismic energy, reducing the risk of damage to the cylinder and key components, and thus enhancing the seismic performance of tall structures.

[0041] This invention achieves crack resistance during the design phase, eliminating the need for post-earthquake reinforcement or repair measures, thereby reducing later maintenance risks and costs. Simultaneously, the early design of the SRC section ensures the long-term safety and reliability of the structure, providing effective technical support for large-scale projects such as tall heat-absorbing towers.

[0042] The number of H-beams arranged in this invention can be determined comprehensively based on the structural stress characteristics and economic efficiency, avoiding the problems of construction complexity and material waste caused by overly dense arrangement, and taking into account both seismic performance and economic feasibility.

[0043] The SRC section of this invention is only 1 / 10 of the total height, which has little impact on the self-weight of the cylinder and the difficulty of construction. Its overall economic efficiency is better than the external steel reinforcement and cross-section thickening scheme.

[0044] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A method for reinforcing upper horizontal cracks in a solar power tower, characterized in that, The application relates to a solar heat absorption tower, and relates to a solar heat absorption tower and a horizontal crack reinforcing method for the upper part of the solar heat absorption tower. The height of the concrete cylinder in the heat absorption tower is determined, and a steel reinforced concrete section is determined at a preset position in the upper part of the concrete cylinder according to the height; A plurality of H-shaped steels are arranged in the circumferential direction of the steel reinforced concrete section. For a region without a dominant direction of wind load, the H-shaped steels are uniformly arranged in the circumferential direction of the concrete cylinder, and the circumferential spacing between adjacent H-shaped steels is determined according to the seismic acceleration value; for a region with a dominant wind direction, the H-shaped steels are non-uniformly arranged in the circumferential direction of the concrete cylinder, and the circumferential spacing is directionally corrected according to the dominant wind direction.

2. The method of claim 1, wherein the horizontal cracks are in the upper portion of the solar receiver tower. The method for directionally correcting the circumferential spacing according to the dominant wind direction comprises the following steps: determining the dominant wind direction; taking the dominant wind direction and the vertical direction thereof as the axis, dividing the circumference of the concrete cylinder into four regions; reducing the circumferential spacing in the regions on both sides of the concrete cylinder which are perpendicular to the dominant wind direction; and increasing the circumferential spacing in the regions on both sides of the concrete cylinder which are parallel to the dominant wind direction.

3. The method of claim 1, wherein the horizontal cracks are in the upper portion of the solar receiver tower. The circumferential spacing between adjacent H-shaped steels is determined according to the seismic acceleration value, which comprises the following steps: for a region with a design seismic acceleration value not less than a preset value, the circumferential spacing tends to a preset lower limit; otherwise, the circumferential spacing tends to a preset upper limit.

4. The method of claim 1, wherein the upper horizontal crack reinforcement is a steel band. Longitudinal steel bars and circumferential steel bars are arranged in the steel reinforced concrete section, and the H-shaped steels are fixed on the concrete in the steel reinforced concrete section through H-shaped steel flange shear nails and H-shaped steel web shear nails.

5. The method of claim 1, wherein the method is used to reinforce horizontal cracks in the upper portion of a solar power tower. The steel reinforced concrete section is provided with a transition section, and the circumferential steel bars in the transition section gradually change from sparse to dense.

6. The method of claim 5, wherein the horizontal cracks are in the upper portion of the solar receiver tower. The transition section is arranged between the reinforced concrete section and the steel reinforced concrete section of the concrete cylinder.

7. The method of claim 6, wherein the horizontal cracks are in the upper portion of the solar receiver tower. The height of the transition section between the reinforced concrete section and the steel reinforced concrete section ranges from 0.60H to 0.62H of the total height H of the concrete cylinder.

8. The method of claim 1, wherein the method is used to reinforce horizontal cracks in the upper portion of a solar power tower. The center position of the steel reinforced concrete section is arranged at 2 / 3 of the total height of the concrete cylinder.

9. A solar heat tower characterized by, The application relates to a solar heat absorption tower, and relates to a solar heat absorption tower and a horizontal crack reinforcing method for the upper part of the solar heat absorption tower.

10. The solar power tower of claim 9, wherein, Longitudinal steel bars and circumferential steel bars are arranged in the steel reinforced concrete section, and the H-shaped steels are fixed on the concrete in the steel reinforced concrete section through H-shaped steel flange shear nails and H-shaped steel web shear nails.

Images