CN116383942A - Design method and device for a main arch structure - Google Patents

Abstract

The invention discloses a design method and device for the main arch structure of a wooden arched corridor bridge. Based on the traditional construction techniques of wooden arched corridor bridges and modern engineering theory, the design method proposed by the invention is used to determine the main arch structure of the wooden arched corridor bridge under a certain span. The arch structure rise-span ratio and the diameter and length of the section of the three-section seedling are determined according to the geometric relationship. The invention can economically, reasonably and reliably design the rise-span ratio of the main arch structure, the length of the stalk and the diameter of the section. The construction techniques of traditional wooden arch bridges have problems such as low reliability, limited basis, and dependence on the experience of craftsmen; the existing design methods based on the family inheritance of craftsmen's pedigree have different design concepts due to different craftsman's pedigree, and the design process is complicated. , have not been scientifically verified by modern mechanics, etc., it is difficult to guarantee safety and economy in practical engineering applications. Compared with the traditional method, the present invention has higher robustness, is more economical, environmentally friendly and reliable, and can conveniently and reliably design the main arch structure of the wooden arch bridge.

Description

Design method and device for a main arch structure

technical field

The invention relates to the design field of wooden arch bridges, in particular to a design method and device for a main arch structure.

Background technique

At present, under the influence of natural factors and human factors, several precious wooden arched bridges such as Wan'an Bridge and Wenxing Bridge have been damaged and destroyed. Since 2003, Shouning, Jingning, Taishun and other places have selectively started repairing and rebuilding in order to restore the original appearance of the historical and cultural atmosphere of the area, better protect and inherit the wooden arch bridge, regain cultural beliefs, and drive the tourism industry. Wooden arcade bridge. However, the number of craftsmen who have mastered the traditional construction skills of wooden arched bridges has decreased sharply due to various reasons, and the construction skills are facing the risk of being lost. Moreover, the traditional construction skills of wooden arched bridges are only passed on through word of mouth through the experience of craftsmen's families, and the structural design is safe. It lacks the verification of modern scientific theory and cannot fully demonstrate the core value of Chinese wooden arched bridges as world cultural heritage.

Therefore, the present invention combines traditional construction techniques and applies modern structural engineering theory to design the main arch structure of the wooden arch bridge. This invention is not only an excavation of the traditional construction techniques of wooden arched corridor bridges, but also an urgent need to protect the remaining wooden arched corridor bridges, and it is also an inheritance of the traditional construction techniques of wooden arched corridor bridges. The invention can provide a reference basis for engineering practical problems such as reconstruction design, construction, repair and reinforcement of the main arch structure of the wooden arch corridor bridge in the future, and has great engineering application value.

Contents of the invention

The object of the present invention is to provide a design method and device for a main arch structure aiming at the deficiencies of the prior art.

The purpose of the present invention is achieved through the following technical solutions: a design method for the main arch structure, comprising the following steps:

Step 1: Select a suitable bridge site according to traffic, landscape requirements and shore foundation conditions, and determine the clear span L of the main arch structure according to the width of the river at the bridge site;

The main arch structure includes a three-section seedling system and a five-section seedling system, and the three-section seedling system includes the first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ , and the second three-section seedling inclined seedling S ₃ , wherein, The first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ and the second three-section seedling inclined seedling S ₃ have the same length; the five-section seedling system includes the first five-section seedling downward inclined seedling W ₁ , the first Five-section seedlings with upward slope W ₂ , five-section seedlings with flat seedlings W ₃ , second and fifth-section seedlings with upward slopes W ₄ , second-fifth-section seedlings with downward slopes W ₅ , among them, first-fifth-section seedlings with downward slopes W ₁ and the second and fifth section seedlings have the same length as the lower inclined seedling W ₅ , the upper inclined seedling W ₂ of the first and fifth section seedlings and the upper inclined seedling W ₄ of the second and fifth section seedlings have the same length;

Step 2: Set the initial rise-to-span ratio f ₁ as 0.17, and calculate the length and cross-sectional diameter of the first three-section inclined seedling S ₁ , the three-section flat seedling S ₂ and the second three-section inclined seedling S ₃ ;

Step 3: Calculate the relationship between the mid-span stress σ of the three-section flat seedling S ₂ and the rise-span ratio f, and take the corresponding rise-span ratio when the mid-span stress of the three-section flat seedling S ₂ is the smallest as the rise-span ratio f ₂ ; Span ratio f ₂ recalculates the lengths of the first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ and the second three-section seedling inclined seedling S ₃ ;

Step 4: Based on the rise-to-span ratio f ₂ and the clear span L, calculate W ₁ for the first and fifth section seedlings, W ₂ for the first and fifth section seedlings, W 3 for the fifth section seedlings, and W ₃ for the second and fifth section seedlings The length and cross-sectional diameter of the upward inclined seedling W ₄ and the second fifth joint seedling downward inclined seedling W ₅ ;

Step 5: According to the lengths of the first three-node oblique seedling S ₁ , the three-node flat seedling S ₂ and the second three-node oblique seedling S ₃ obtained in step 3, and the first three-node oblique seedling obtained in step 2 S ₁ , the cross-sectional diameters of the flat seedlings S ₂ of the three-section seedlings and the inclined seedlings S ₃ of the second and third-section seedlings, and the lower inclined seedlings W ₁ of the first and fifth section seedlings, the upper inclined seedlings W ₂ of the first and fifth section seedlings obtained in step 4, Establish the finite element model of the main arch structure based on the length and cross-sectional diameter of the five-section flat seedling W ₃ , the second-fifth-section up-slope W ₄ , and the second-fifth-section down-slope W ₅ , and calculate all the members of the main arch structure If the stress or deflection of some members of the main arch structure exceeds the limit specified in the "Standards for Design of Timber Structures" GB50005-2017, increase the cross-sectional diameter of the overrunning members and recalculate all the members of the main arch structure. The stress and deflection of the members until the stress and deflection of all the members of the main arch structure are less than the specification limit.

Further, the step 2 specifically includes the following sub-steps:

Step 2.1: Set the initial rise-span ratio f ₁ of the main arch structure to 0.17, and use the formula (1) to calculate the first three-section inclined seedling S ₁ , the three-section flat seedling S ₂ and the second three-section inclined seedling The length l ₁ of S ₃ :

Step 2.2: The cross-sectional diameters of the first three-section seedling _S1 and the second three-section seedling _S3 are both _D1 , and the cross-section diameter of the three-section flat seedling _S2 is _D2 ; design the first The cross-section diameters of the three-section oblique seedling S ₁ and the second three-section oblique seedling S ₃ are not less than 11.4l ₁ +226 , and the cross-section diameter of the three-section flat seedling S ₂ is not less than 10.8l ₁ +211 .

Further, the step 3 specifically includes the following sub-steps:

Step 3.1: Take the left half of the three-section seedling system as the basic system of the force method, and calculate the mid-span stress σ of the three-section seedling flat seedling S ₂ by the following formula:

Among them, M is the mid-span bending moment of the three-section flat seedling _S2 , and the calculation formula is as follows:

自由项Δ_1P的计算公式为/>

Among them, the calculation formula of the coefficient _δ11 is

The calculation formula of the free term Δ _1P is />

Among them, l is the length of the first three-section oblique seedling S ₁ , the three-section flat seedling S ₂ and the second three-section oblique seedling S ₃ when the rise-span ratio is f; The included angle between the inclined seedling W ₁ of the first five-section seedling and the horizontal plane and the angle between the inclined seedling S ₁ of the first three-section seedling and the horizontal plane; θ=arcsin(H/l), H=f*L, and H is the main arch structure E is the modulus of elasticity; I ₁ is the section moment of inertia of the first three-section inclined seedling S ₁ and the second three-section inclined seedling S ₃ , and I ₂ is the section moment of inertia of the three-section flat seedling S ₂ ; q is the uniform load value;

The moment balance equation is established by using the intersection point of the bottom of the inclined seedling S ₁ of the first three-section seedling and the horizontal plane as the origin, and the axial force F of the three-section flat seedling S ₂ is derived:

In the formula, F ₁ is the external load of the three-section seedling system, its value is 0.135qL, and the acting position is the 1/4 position of the three-section seedling flat seedling S ₂ ; F ₂ is the external load of the three-section seedling system, and its value is 0.205qL, and the action position is at the intersection of the first three-section seedling oblique seedling S ₁ and the three-section flat seedling S ₂ ;

Through the formula (2) - formula (4), the relationship between the mid-span stress σ and the rise-span ratio f of the three-section seedling flat seedling _S2 is obtained;

Step 3.2: Based on the relationship between the mid-span stress σ of the three-section flat seedling S ₂ determined in step 3.1 and the rise-span ratio f, take the corresponding rise-span ratio when the mid-span stress of the three-section flat seedling S ₂ is the smallest as the rise-span ratio f ₂ ; recalculate the lengths of the first three-section oblique seedling S ₁ , the three-section flat seedling S ₂ , and the second three-section oblique seedling S ₃ through formula ( ₁ ) using the rise-span ratio f 2 , which is l ₂ .

Further, the step 4 specifically includes the following sub-steps:

y₃＝f₂L；Step _4.1 : Calculate θ ₂ =arcsin(H ₂ /l ₂ ), H ₂ =f ₂ *L based on the span ratio f ₂ The bridge direction is the x axis, and the vertical bridge direction is the y axis to establish a plane coordinate system, and it is determined that the coordinates of the intersection point of the oblique seedling S ₁ of the first three-section seedling and the flat seedling S ₂ of the three-section seedling are (x ₃ , y ₃ ), wherein,

y ₃ =f ₂ L;

Step 4.2: Determine the coordinates of the intersection point of the downward slanting seedling W ₁ of the first fifth section seedling and the upward slanting seedling W ₂ of the first fifth section seedling as (x ₆ , y ₆ ), where,

In the formula, β is the length ratio of the downward slanting seedling W ₁ of the first fifth section seedling to the upper slanting seedling W ₂ of the first fifth section seedling, and the calculation formula is as follows:

Determine subsequently that the coordinates of the intersection point of the inclined seedling W ₁ and the vertical plane of the first fifth section seedling are (x ₅ , y ₅ ), wherein, x ₅ =0,

y₈＝y₃+h；其中，k为第一五节苗上斜苗W₂的斜率，

h为第一五节苗上斜苗W₂与五节苗平苗W₃的交点到第一三节苗斜苗S1的垂直距离，h＝L/80；Determine again that the coordinates of the intersection of the first five-section seedling on the oblique seedling W ₂ and the five-section seedling flat seedling W ₃ are (x ₈ , y ₈ ), wherein,

y ₈ =y ₃ +h; among them, k is the slope of the slope seedling W ₂ of the first and fifth seedlings,

h is the vertical distance from the intersection point of the first five-section seedling on the inclined seedling W ₂ and the fifth-section seedling flat seedling W ₃ to the first three-section seedling inclined seedling S1, h=L/80;

Calculate the length P ₁ of the first and fifth section seedlings with downward slope W ₁ and the second fifth section with downward slope W ₅ ,

Calculate the length P ₂ of the slanting seedling W ₂ of the first fifth section seedling and the slanting seedling W ₄ of the second fifth section seedling,

Calculate the length P ₃ of the five-section seedling flat seedling W ₃ , P ₃ =L-2x ₈ ;

Step 4.3: The section diameters of the first and fifth section seedlings W ₁ and the second fifth section seedlings W ₅ are both D ₃ , and the first and fifth section seedlings W ₂ and the second fifth section are both D 3 . The cross-section diameters of the upper inclined seedlings W ₄ of _the section seedlings are all D ₄ , and the cross-sectional diameters of the flat seedlings W ₃ of the five-section seedlings are all D ₅ ; The cross-sectional diameter D ₃ of the oblique seedling W ₅ is not less than 9.4P ₁ +217, the cross-sectional diameter D 4 _of the oblique seedling W ₂ of the first and fifth section seedlings and the upper oblique seedling W ₄ of the second fifth section seedling is not less than 11.5P ₂ +183 , and the cross-sectional diameter D ₅ of the five-section seedling flat seedling W ₃ is not less than 13.3P ₃ +230.

The present invention also provides a design device for a main arch structure, including one or more processors for realizing the above-mentioned design method for a main arch structure.

The present invention also provides a computer-readable storage medium, on which a program is stored, and when the program is executed by a processor, it is used to realize the design method of the above-mentioned main arch structure.

The beneficial effects of the present invention are:

(1) The method for determining the rise-span ratio in the present invention can quickly determine the value of the rise-span ratio of the main arch structure, and while reducing the construction consumables of the main arch structure, the stress of the three-section seedling flat seedling of the main arch structure can be made under the same load minimum;

(2) The method for determining the coordinates of the bull's head in the present invention is beneficial to the stress of the main arch structure. In addition, the relationship between the nodes of the main arch structure is expressed by mathematical expressions, which is convenient for quickly and accurately calculating the length of each seedling stem of the five-section seedling system;

(3) the seedling stalk section diameter design formula among the present invention has realized the rapid design selection of the stalk component section;

Description of drawings

Fig. 1 is the flowchart of a kind of design method of main arch structure;

Fig. 2 is a schematic diagram of the main arch structure;

Fig. 3 is the schematic diagram of three section seedling system;

Fig. 4 is the bending moment diagram solved by the force method of the three-section seedling system, wherein, Fig. 4 (a) is a schematic diagram of the semi-structure of the three-section seedling system, Fig. 4 (b) is the bending moment diagram of the statically determinate foundation of the structure under the action of unit force, and Fig. 4 ( c) is the bending moment diagram of the original structure load acting on the statically determinate foundation of the structure;

Fig. 5 is a relationship diagram between mid-span stress σ and rise-span ratio f of three-section seedling flat seedling _S2 ;

Fig. 6 is a schematic diagram of the finite element model of the main arch structure;

Fig. 7 is a structural diagram of a design device for a main arch structure.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, rather than all Example. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts are within the protection scope of the present invention.

As shown in Figure 1, the present invention provides a kind of design method of the main arch structure of wooden arched corridor bridge, comprises the following steps:

Step 1: Select a suitable bridge site according to traffic, landscape requirements and shore foundation conditions, and determine the clear span L of the main arch structure according to the width of the river at the bridge site. The clear span L is basically the same as the width of the river at the bridge site.

As shown in Figure 2, _the main arch structure includes a three-section seedling system and a five-section seedling system, and the three-section seedling system includes the first three-section seedling inclined seedling S ₁ , the three-section Seedling S ₃ , wherein the lengths of the first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ and the second three-section seedling oblique seedling S ₃ are the same; the five-section seedling system includes the first five-section seedling downward oblique Seedling W ₁ , up-slanting seedlings W ₂ of the first and fifth joints, flat seedlings of the fifth joints W ₃ , upward-slanting seedlings of the second and fifth joints W ₄ , downward-slanting seedlings of the second and fifth joints W ₅ , of which, the first and fifth joints The lengths of the lower oblique seedlings W _{1 of} the node seedlings and the lower oblique seedlings W ₅ of the second and fifth node seedlings are the same, and the lengths of the upper oblique seedlings W ₂ of the first and fifth node seedlings and the upper oblique seedlings W ₄ of the second and fifth node seedlings are the same.

In this embodiment, the main arch structure is the main arch structure of a pre-built wooden arch bridge, and the clear span L is 29.5m.

Step 2: Set the initial rise-to-span ratio f ₁ as 0.17, and calculate the length and cross-sectional diameter of the first three-section oblique seedling S ₁ , the three-section flat seedling S ₂ , and the second three-section oblique seedling S ₃ .

The step 2 specifically includes the following sub-steps:

Step 2.1: Set the initial rise-span ratio f ₁ of the main arch structure to 0.17, and use the formula (1) to calculate the first three-section inclined seedling S ₁ , the three-section flat seedling S ₂ and the second three-section inclined seedling The length l ₁ of S ₃ :

In this embodiment, the length l ₁ of the first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ and the second three-section seedling inclined seedling S ₃ is calculated to be 10.67 m.

Step 2.2: The cross-sectional diameters of the first three-section seedling _S1 and the second three-section seedling _S3 are both _D1 , and the cross-section diameter of the three-section flat seedling _S2 is _D2 ; design the first The cross-section diameters of the three-section oblique seedling S ₁ and the second three-section oblique seedling S ₃ are not less than 11.4l ₁ +226 , and the cross-section diameter of the three-section flat seedling S ₂ is not less than 10.8l ₁ +211 .

In the present embodiment, the cross- _sectional diameter D 1 of the first three-section seedling inclined seedling S ₁ and the second three-section seedling inclined seedling S ₃ is designed to be 327 mm, and the cross-sectional diameter D ₂ of the three-section seedling flat seedling S ₂ is designed to be 347 mm.

Step 3: Calculate the relationship between the mid-span stress σ of the three-section flat seedling S ₂ and the rise-span ratio f, and take the corresponding rise-span ratio when the mid-span stress of the three-section flat seedling S ₂ is the smallest as the rise-span ratio f ₂ ; Span ratio f ₂ recalculates the lengths of the first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ and the second three-section seedling inclined seedling S ₃ .

The step 3 specifically includes the following sub-steps:

Step 3.1: Take the left half of the three-section seedling system as the basic system of the force method, and calculate the mid-span stress σ of the three-section seedling flat seedling S ₂ by the following formula:

Among them, M is the mid-span bending moment of the three-section flat seedling _S2 , and the calculation formula is as follows:

自由项Δ_1P的计算公式为/>

Among them, the calculation formula of the coefficient _δ11 is

The calculation formula of the free term Δ _1P is />

Among them, l is the length of the first three-section oblique seedling S ₁ , the three-section flat seedling S ₂ and the second three-section oblique seedling S ₃ when the rise-span ratio is f; The angle between W ₁ of the first and fifth section seedlings and the horizontal plane, and the angle between the first and third section seedlings S ₁ and the horizontal plane, the angle between the first and fifth section seedlings W ₁ and the first and third section seedlings S ₁ Parallel; _θ =arcsin(H/ _l ), H=f*L, H is the vector height of the main arch structure; E is the modulus of elasticity; The section moment of inertia of seedling S ₃ , I ₂ is the section moment of inertia of three-section flat seedling S ₂ ; q is the uniformly distributed load value, which can be taken as 1kN/m; f is the rise-span ratio.

The moment balance equation is established by using the intersection point of the bottom of the inclined seedling S ₁ of the first three-section seedling and the horizontal plane as the origin, and the axial force F of the three-section flat seedling S ₂ is derived:

In the formula, F ₁ is the external load of the three-section seedling system, its value is 0.135qL, and the acting position is the 1/4 position of the three-section seedling flat seedling S ₂ ; F ₂ is the external load of the three-section seedling system, and its value 0.205qL, and the action location is at the intersection of the first three-node oblique seedling S ₁ and the three-node flat seedling S ₂ , as shown in Figure 3 and Figure 4.

Through the formula (2) - formula (4), the relationship between the mid-span stress σ and the rise-span ratio f of the three-section seedling and flat seedling S ₂ is obtained.

In this embodiment, the relationship between the mid-span stress σ and the rise-span ratio f of the three-section seedling and flat seedling _S2 is shown in Fig. 5 .

Step 3.2: Based on the relationship between the mid-span stress σ of the three-section flat seedling S ₂ determined in step 3.1 and the rise-span ratio f, take the corresponding rise-span ratio when the mid-span stress of the three-section flat seedling S ₂ is the smallest as the rise-span ratio f ₂ ; recalculate the lengths of the first three-section oblique seedling S ₁ , the three-section flat seedling S ₂ , and the second three-section oblique seedling S ₃ through formula ( ₁ ) using the rise-span ratio f 2 , which is l ₂ .

In this embodiment, it can be obtained from Fig. 5 that when the mid-span stress of the three-section seedling _S2 is the smallest, the corresponding rise-span ratio value is 0.175, that is, the rise-span ratio f ₂ =0.175; the use rise-span ratio f ₂ =0.175 The lengths of the first three-node oblique seedling S ₁ , the three-node flat seedling S ₂ and the second three-node oblique seedling S ₃ are calculated again by formula (1), and l ₂ =10.72m is obtained.

Step 4: Based on the rise-to-span ratio f ₂ and the clear span L, calculate W ₁ for the first and fifth section seedlings, W ₂ for the first and fifth section seedlings, W 3 for the fifth section seedlings, and W ₃ for the second and fifth section seedlings The length and cross-sectional diameter of the upward inclined seedling W ₄ and the second fifth joint seedling downward inclined seedling W ₅ ;

The step 4 specifically includes the following sub-steps:

_Step 4.1: Calculate θ ₂ =arcsin(H ₂ /l ₂ ), H ₂ =f ₂ *L based on the rise-span ratio f ₂ ; The point of intersection is the origin, the longitudinal bridge direction is the x-axis, and the vertical bridge direction is the y-axis to establish a plane coordinate system, the coordinates are (0,0), determine the intersection point of the first three-section seedling inclined seedling S ₁ and the three-section flat seedling S ₂ The coordinates of are (x ₃ , y ₃ ), where,

Step 4.2: Determine the coordinates of the intersection point of the downward slanting seedling W ₁ of the first fifth section seedling and the upward slanting seedling W ₂ of the first fifth section seedling as (x ₆ , y ₆ ), where,

In the formula, β is the length ratio of the downward slanting seedling W ₁ of the first fifth section seedling to the upper slanting seedling W ₂ of the first fifth section seedling, and the calculation formula is as follows:

Determine subsequently that the coordinates of the intersection point of the inclined seedling W ₁ and the vertical plane of the first fifth section seedling are (x ₅ , y ₅ ), wherein, x ₅ =0,

y₈＝y₃+h；其中，k为第一五节苗上斜苗W₂的斜率，

h为第一五节苗上斜苗W₂与五节苗平苗W₃的交点到第一三节苗斜苗S1的垂直距离，h＝L/80；Determine again that the coordinates of the intersection of the first five-section seedling on the oblique seedling W ₂ and the five-section seedling flat seedling W ₃ are (x ₈ , y ₈ ), wherein,

y ₈ =y ₃ +h; among them, k is the slope of the slope seedling W ₂ of the first and fifth seedlings,

h is the vertical distance from the intersection point of the first five-section seedling on the inclined seedling W ₂ and the fifth-section seedling flat seedling W ₃ to the first three-section seedling inclined seedling S1, h=L/80;

By coordinates (x ₅ , y ₅ ) and coordinates (x ₆ , y ₆ ), the lengths P ₁ of the first and fifth section seedlings W ₁ and the second fifth section seedlings W ₅ are calculated,

Through the coordinates (x ₆ , y ₆ ) and coordinates (x ₈ , y ₈ ), the length P ₂ of the upper inclined seedling W ₂ of the first fifth section seedling and the upper inclined seedling W ₄ of the second fifth section seedling is calculated,

Calculate the length P ₃ of the five-section seedling flat seedling W ₃ , P ₃ =L-2x ₈ ;

In this embodiment, h=368.75mm; θ ₂ is 28.8°; β is 0.71; x ₆ =6.490m, y ₆ =3.989m; x ₅ =0m, y ₅ =0.421m; x ₈ =12.143m, y ₈ = 5.531m; the length P ₁ of the first and fifth section seedlings W ₁ and the second and fifth section seedlings W ₅ is 7.406m; the first and fifth section seedlings W ₂ and the second and fifth section The length P ₂ of the inclined seedling W ₄ is 5.860 m; the length P ₃ of the five-section seedling W ₃ is 5.213 m.

Step 4.3: The section diameters of the first and fifth section seedlings W ₁ and the second fifth section seedlings W ₅ are both D ₃ , and the first and fifth section seedlings W ₂ and the second fifth section are both D 3 . The cross-section diameters of the upper inclined seedlings W ₄ of _the section seedlings are all D ₄ , and the cross-sectional diameters of the flat seedlings W ₃ of the five-section seedlings are all D ₅ ; The cross-sectional diameter D ₃ of the oblique seedling W ₅ is not less than 9.4P ₁ +217, the cross-sectional diameter D 4 _of the oblique seedling W ₂ of the first and fifth section seedlings and the upper oblique seedling W ₄ of the second fifth section seedling is not less than 11.5P ₂ +183 , and the cross-sectional diameter D ₅ of the five-section seedling flat seedling W ₃ is not less than 13.3P ₃ +230.

In the present embodiment, the cross-sectional diameter D ₃ of the first and fifth section seedlings W ₁ and the second and fifth section seedlings W ₅ is 286mm, and the first and fifth section seedlings W ₂ and the second and fifth section seedlings are 286mm. The cross-section diameter D _{4 of the} inclined seedling W ₄ is 250 mm; the cross-section diameter D ₅ of the five-section flat seedling W ₃ is 286 mm.

Step 5: According to the lengths of the first three-node oblique seedling S ₁ , the three-node flat seedling S ₂ and the second three-node oblique seedling S ₃ obtained in step 3, and the first three-node oblique seedling obtained in step 2 S ₁ , the cross-sectional diameters of the flat seedlings S ₂ of the three-section seedlings and the inclined seedlings S ₃ of the second and third-section seedlings, and the lower inclined seedlings W ₁ of the first and fifth section seedlings, the upper inclined seedlings W ₂ of the first and fifth section seedlings obtained in step 4, Establish the finite element model of the main arch structure based on the length and cross-sectional diameter of the five-section flat seedling W ₃ , the second-fifth-section up-slope W ₄ , and the second-fifth-section down-slope W ₅ , and calculate all the members of the main arch structure If the stress or deflection of some members of the main arch structure exceeds the limit specified in the "Standards for Design of Timber Structures" GB50005-2017, increase the cross-sectional diameter of the overrunning members and recalculate all the members of the main arch structure. The stress and deflection of the members until the stress and deflection of all the members of the main arch structure are less than the specification limit.

In this embodiment, the finite element model of the main arch structure is shown in Figure 6. Under the joint action of dead and live loads, the maximum stress of the main arch structure is located at the mid-span of Wujie Miaopingmiao W ₃ , which is -8.8MPa, which is less than the material The design value of bending strength is 11MPa. The maximum deflection is located in the mid-span of Wujiemiaopingmiao W ₃ , and the deflection ratio is 1/359, which is less than the specification limit of 1/250.

Example 2

Referring to FIG. 7 , an apparatus for designing a main arch structure provided by an embodiment of the present invention includes one or more processors for implementing the method for designing a main arch structure in the above-mentioned embodiments.

The embodiment of the device for designing the main arch structure of the present invention can be applied to any device with data processing capability, and any device with data processing capability can be a device or device such as a computer. The device embodiments can be implemented by software, or by hardware or a combination of software and hardware. Taking software implementation as an example, as a device in a logical sense, it is formed by reading the corresponding computer program instructions in the non-volatile memory into the memory for operation by the processor of any device capable of data processing. From the hardware level, as shown in Figure 7, it is a hardware structure diagram of any device with data processing capability where the design device of the main arch structure of the present invention is located, except for the processor, memory, network interface, In addition to the non-volatile memory, any device with data processing capability where the device in the embodiment is usually based on the actual function of any device with data processing capability may also include other hardware, which will not be repeated here.

For the implementation process of the functions and effects of each unit in the above device, please refer to the implementation process of the corresponding steps in the above method for details, and will not be repeated here.

As for the device embodiment, since it basically corresponds to the method embodiment, for related parts, please refer to the part description of the method embodiment. The device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network elements. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the present invention. It can be understood and implemented by those skilled in the art without creative effort.

An embodiment of the present invention also provides a computer-readable storage medium, on which a program is stored. When the program is executed by a processor, the method for designing the main arch structure in the above-mentioned embodiments is realized.

The computer-readable storage medium may be an internal storage unit of any device capable of data processing described in any of the foregoing embodiments, such as a hard disk or a memory. The computer-readable storage medium may also be an external storage device of any device with data processing capabilities, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), an SD card, a flash memory card, etc. (Flash Card) etc. Further, the computer-readable storage medium may also include both an internal storage unit of any device capable of data processing and an external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by any device capable of data processing, and may also be used to temporarily store data that has been output or will be output.

Those of ordinary skill in the art can understand that the above description is only a preferred example of the invention, and is not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, for those skilled in the art, it can still be understood. The technical solutions described in the foregoing examples are modified, or some of the technical features are equivalently replaced. All modifications, equivalent replacements, etc. within the spirit and principles of the invention shall be included in the scope of protection of the invention.

Claims (6)

1. a design method of main arch structure, is characterized in that, comprises the following steps: Step 1: Select a suitable bridge site according to traffic, landscape requirements and shore foundation conditions, and determine the clear span L of the main arch structure according to the width of the river at the bridge site; The main arch structure includes a three-section seedling system and a five-section seedling system, and the three-section seedling system includes the first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ , and the second three-section seedling inclined seedling S ₃ , wherein, The first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ and the second three-section seedling inclined seedling S ₃ have the same length; the five-section seedling system includes the first five-section seedling downward inclined seedling W ₁ , the first Five-section seedlings with upward slope W ₂ , five-section seedlings with flat seedlings W ₃ , second and fifth-section seedlings with upward slopes W ₄ , second-fifth-section seedlings with downward slopes W ₅ , among them, first-fifth-section seedlings with downward slopes W ₁ and the second and fifth section seedlings have the same length as the lower inclined seedling W ₅ , the upper inclined seedling W ₂ of the first and fifth section seedlings and the upper inclined seedling W ₄ of the second and fifth section seedlings have the same length; Step 2: Set the initial rise-to-span ratio f ₁ as 0.17, and calculate the length and cross-sectional diameter of the first three-section inclined seedling S ₁ , the three-section flat seedling S ₂ and the second three-section inclined seedling S ₃ ; Step 3: Calculate the relationship between the mid-span stress σ of the three-section flat seedling S ₂ and the rise-span ratio f, and take the corresponding rise-span ratio when the mid-span stress of the three-section flat seedling S ₂ is the smallest as the rise-span ratio f ₂ ; Span ratio f ₂ recalculates the lengths of the first three-section seedling inclined seedling S ₁ , the three-section seedling flat seedling S ₂ and the second three-section seedling inclined seedling S ₃ ; Step 4: Based on the rise-to-span ratio f ₂ and the clear span L, calculate W ₁ for the first and fifth section seedlings, W ₂ for the first and fifth section seedlings, W 3 for the fifth section seedlings, and W ₃ for the second and fifth section seedlings The length and cross-sectional diameter of the upward inclined seedling W ₄ and the second fifth joint seedling downward inclined seedling W ₅ ; Step 5: According to the lengths of the first three-node oblique seedling S ₁ , the three-node flat seedling S ₂ and the second three-node oblique seedling S ₃ obtained in step 3, and the first three-node oblique seedling obtained in step 2 S ₁ , the cross-sectional diameters of the flat seedlings S ₂ of the three-section seedlings and the inclined seedlings S ₃ of the second and third-section seedlings, and the lower inclined seedlings W ₁ of the first and fifth section seedlings, the upper inclined seedlings W ₂ of the first and fifth section seedlings obtained in step 4, Establish the finite element model of the main arch structure based on the length and cross-sectional diameter of the five-section flat seedling W ₃ , the second-fifth-section up-slope W ₄ , and the second-fifth-section down-slope W ₅ , and calculate all the members of the main arch structure If the stress or deflection of some members of the main arch structure exceeds the limit specified in the "Standards for Design of Timber Structures" GB50005-2017, increase the cross-sectional diameter of the overrunning members and recalculate all the members of the main arch structure. The stress and deflection of the members until the stress and deflection of all the members of the main arch structure are less than the specification limit. 2. the design method of a kind of main arch structure according to claim 1, is characterized in that, described step 2 specifically comprises the following sub-steps: Step 2.1: Set the initial rise-span ratio f ₁ of the main arch structure to 0.17, and use the formula (1) to calculate the first three-section inclined seedling S ₁ , the three-section flat seedling S ₂ and the second three-section inclined seedling The length l ₁ of S ₃ :

Step 2.2: The cross-sectional diameters of the first three-section seedling _S1 and the second three-section seedling _S3 are both _D1 , and the cross-section diameter of the three-section flat seedling _S2 is _D2 ; design the first The cross-section diameters of the three-section oblique seedling S ₁ and the second three-section oblique seedling S ₃ are not less than 11.4l ₁ +226 , and the cross-section diameter of the three-section flat seedling S ₂ is not less than 10.8l ₁ +211 . 3. the design method of a kind of main arch structure according to claim 2, is characterized in that, described step 3 specifically comprises the following sub-steps: Step 3.1: Take the left half of the three-section seedling system as the basic system of the force method, and calculate the mid-span stress σ of the three-section seedling flat seedling S ₂ by the following formula:

Among them, M is the mid-span bending moment of the three-section flat seedling _S2 , and the calculation formula is as follows:

Among them, the calculation formula of the coefficient _δ11 is

The calculation formula of the free term Δ _1P is />

Among them, l is the length of the first three-section oblique seedling S ₁ , the three-section flat seedling S ₂ and the second three-section oblique seedling S ₃ when the rise-span ratio is f; The included angle between the inclined seedling W ₁ of the first five-section seedling and the horizontal plane and the angle between the inclined seedling S ₁ of the first three-section seedling and the horizontal plane; θ=arcsin(H/l), H=f*L, and H is the main arch structure E is the modulus of elasticity; I ₁ is the section moment of inertia of the first three-section inclined seedling S ₁ and the second three-section inclined seedling S ₃ , and I ₂ is the section moment of inertia of the three-section flat seedling S ₂ ; q is the uniform load value; The moment balance equation is established by using the intersection point of the bottom of the inclined seedling S ₁ of the first three-section seedling and the horizontal plane as the origin, and the axial force F of the three-section flat seedling S ₂ is derived:

In the formula, F ₁ is the external load of the three-section seedling system, its value is 0.135qL, and the acting position is the 1/4 position of the three-section seedling flat seedling S ₂ ; F ₂ is the external load of the three-section seedling system, and its value is 0.205qL, and the action position is at the intersection of the first three-section seedling oblique seedling S ₁ and the three-section flat seedling S ₂ ; Through the formula (2) - formula (4), the relationship between the mid-span stress σ and the rise-span ratio f of the three-section seedling flat seedling _S2 is obtained; Step 3.2: Based on the relationship between the mid-span stress σ of the three-section flat seedling S ₂ determined in step 3.1 and the rise-span ratio f, take the corresponding rise-span ratio when the mid-span stress of the three-section flat seedling S ₂ is the smallest as the rise-span ratio f ₂ ; recalculate the lengths of the first three-section oblique seedling S ₁ , the three-section flat seedling S ₂ , and the second three-section oblique seedling S ₃ through formula ( ₁ ) using the rise-span ratio f 2 , which is l ₂ . 4. the design method of a kind of main arch structure according to claim 3, is characterized in that, described step 4 specifically comprises the following sub-steps: Step _4.1 : Calculate θ ₂ =arcsin(H ₂ /l ₂ ), H ₂ =f ₂ *L based on the span ratio f ₂ The bridge direction is the x axis, and the vertical bridge direction is the y axis to establish a plane coordinate system, and it is determined that the coordinates of the intersection point of the oblique seedling S ₁ of the first three-section seedling and the flat seedling S ₂ of the three-section seedling are (x ₃ , y ₃ ), wherein,

y ₃ =f ₂ L; Step 4.2: Determine the coordinates of the intersection point of the downward slanting seedling W ₁ of the first fifth section seedling and the upward slanting seedling W ₂ of the first fifth section seedling as (x ₆ , y ₆ ), where,

In the formula, β is the length ratio of the downward slanting seedling W ₁ of the first fifth section seedling to the upper slanting seedling W ₂ of the first fifth section seedling, and the calculation formula is as follows:

Determine subsequently that the coordinates of the intersection point of the inclined seedling W ₁ and the vertical plane of the first fifth section seedling are (x ₅ , y ₅ ), wherein, x ₅ =0,

Determine again that the coordinates of the intersection of the first five-section seedling on the oblique seedling W ₂ and the five-section seedling flat seedling W ₃ are (x ₈ , y ₈ ), wherein,

y ₈ =y ₃ +h; among them, k is the slope of the slope seedling W ₂ of the first and fifth seedlings,

h is the vertical distance from the intersection point of the first five-section seedling on the inclined seedling W ₂ and the fifth-section seedling flat seedling W ₃ to the first three-section seedling inclined seedling S1, h=L/80; Calculate the length P ₁ of the first and fifth section seedlings with downward slope W ₁ and the second fifth section with downward slope W ₅ ,

Calculate the length P ₂ of the slanting seedling W ₂ of the first fifth section seedling and the slanting seedling W ₄ of the second fifth section seedling,

Calculate the length P ₃ of the five-section seedling flat seedling W ₃ , P ₃ =L-2x ₈ ; Step 4.3: The section diameters of the first and fifth section seedlings W ₁ and the second fifth section seedlings W ₅ are both D ₃ , and the first and fifth section seedlings W ₂ and the second fifth section are both D 3 . The cross-section diameters of the upper inclined seedlings W ₄ of _the section seedlings are all D ₄ , and the cross-sectional diameters of the flat seedlings W ₃ of the five-section seedlings are all D ₅ ; The cross-sectional diameter D ₃ of the oblique seedling W ₅ is not less than 9.4P ₁ +217, the cross-sectional diameter D 4 _of the oblique seedling W ₂ of the first and fifth section seedlings and the upper oblique seedling W ₄ of the second fifth section seedling is not less than 11.5P ₂ +183 , and the cross-sectional diameter D ₅ of the five-section seedling flat seedling W ₃ is not less than 13.3P ₃ +230. 5. A device for designing a main arch structure, characterized in that it comprises one or more processors for implementing the method for designing a main arch structure according to any one of claims 1-4. 6. A computer-readable storage medium with a program stored thereon, characterized in that, when the program is executed by a processor, it is used to realize the design method of the main arch structure according to any one of claims 1-4.

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