CN116244793B - Method for calculating design wind load of bent torsion column spiral Liang Jingguan tower based on GLF method - Google Patents

Method for calculating design wind load of bent torsion column spiral Liang Jingguan tower based on GLF method Download PDF

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CN116244793B
CN116244793B CN202211726995.0A CN202211726995A CN116244793B CN 116244793 B CN116244793 B CN 116244793B CN 202211726995 A CN202211726995 A CN 202211726995A CN 116244793 B CN116244793 B CN 116244793B
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赵爽
张成涛
姜伟
晏致涛
时易
岳佳豪
陈家豪
黄枭雄
刘永杰
何泉江
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Chongqing University of Science and Technology
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Abstract

The invention discloses a method for calculating the design wind load of a bent torsion column spiral Liang Jingguan tower based on a GLF method, wherein the appearance and the mass distribution of a landscape tower are unevenly changed along the height, and the method comprises the following steps: firstly, determining related parameters of a landscape tower structure, related coefficients of roughness of the ground and reference coefficients of wind conditions; then according to the load specification, calculating the gust load factor G and the average wind load of the building with the shape unchanged along the height direction based on the GLF methodThen introducing a wind direction angle change correction coefficient eta (theta) to correct the wind load factor G to obtain a corrected wind load factor G * (θ); finally, using the corrected gust load factor G * (theta) calculating the corrected static equivalent wind loadAs a design wind load. The invention has the beneficial effects that: the method provided by the conventional load specification is corrected by considering the wind direction angle change factors, and the design wind load calculation method closer to the actual wind load is provided, is concise and accurate, is used for guiding the structural design and material selection of the landscape tower, and is beneficial to improving the design safety.

Description

Method for calculating design wind load of bent torsion column spiral Liang Jingguan tower based on GLF method
Technical Field
The invention belongs to the technical field of tower building design, relates to determination of tower building design load with uneven appearance and mass distribution, and particularly relates to a method for calculating special-shaped landscape tower design wind load based on a Gust Load Factor (GLF) method.
Background
In wind-resistant designs for towering structures, the following problems should be considered: the structure is ensured to have enough strength and can reliably bear the internal force under the action of wind load; the structure must have sufficient rigidity to control displacement of the towering structure under horizontal loads; reasonable structural system and appearance are selected. Structural wind load design values are a precondition for a designer to perform preliminary structural design. In engineering design application, for a general high-rise structure, the maximum wind load born by the main body supporting structure is not higher than the allowable stress value calculated according to the section characteristics and materials at the corresponding position. Therefore, the wind load design value of the structure is accurately and efficiently calculated, and the wind load design value has direct influence on the safety, applicability and economy of the structure.
In engineering design application, the wind load standard value W is generally adopted k To calculate the wind loading effect to which the structure is subjected. Reasonable wind-resistant design is in addition to the structural materials and the construction technology, and the structure W k Is a precondition that a designer obtains a load design value when carrying out preliminary structure design, and has direct influence on the safety, applicability and economy of the structure. The gust load factor G is an important parameter in the structural wind resistance design, but the unique profile of the landscape tower can have a beneficial or detrimental effect and require further investigation.
Although dynamic time-course analysis can obtain wind vibration response of the structure, wind load calculated by adopting load specification is concise, convenient and time-saving, and the method is still widely adopted by designers at the present stage. The wind load calculated by the specification should have an effect of enabling equivalent wind vibration response of the tower type building and actual maximum wind vibration response. The design of the landscape tower by adopting the accurate equivalent static wind load is a precondition for ensuring the safe use of the building. The dynamic sensitive structure gust load factor calculation method is recommended in the current Canadian Specification (NR 24-28/2015E, 2015). However, the specification does not consider the influence of the wind direction angle on the G in the GLF method, and in addition, the influence of the quality and the wind shielding area of the landscape tower along the uneven change of the height on the wind load factor is large. When the random vibration theory is adopted to calculate the equivalent static wind load of the landscape tower, the expression relates to complex multiple integration, the appearance and the mass distribution of the landscape tower are irregular, and the expression is difficult to summarize by a unified expression. Therefore, in order to meet the engineering practice demands of landscape tower design, not only is the rationality of landscape tower wind resistance design by using the existing load specification assessed, but also a simple and accurate landscape tower design wind load calculation method is necessary.
Disclosure of Invention
In view of this, the present invention provides a method for calculating the wind load of a twist column spiral Liang Jingguan tower design based on the GLF method.
The technical scheme is as follows:
the method for calculating the design wind load of the bent torsion column spiral Liang Jingguan tower based on the GLF method is characterized in that the appearance and the mass distribution of the landscape tower are unevenly changed along the height, and the method comprises the following steps:
s1, determining related parameters of a landscape tower structure, related coefficients of the roughness of the ground and a wind condition reference coefficient;
s2, calculating gust load factors of buildings with unchanged shapes along the height direction based on a GLF method according to load specificationsG and average wind loadThe height of the building with the shape unchanged along the height direction is the same as the height of the landscape tower, and the width of the building is the same as the structural width of the landscape tower;
s3, introducing a wind direction angle change correction coefficient eta (theta) to correct the wind load factor G to obtain a corrected wind load factor G * (θ)，
G * (θ)＝G×η(θ)，
Wherein the wind direction angle change correction coefficient η (θ) is determined based on the profile of the landscape tower;
s4, using the corrected gust load factor G * (theta) calculating the corrected static equivalent wind loadAs design wind load, static equivalent wind load +.>The calculation expression of (2) is +.>
In one embodiment, the landscape tower comprises three sections, namely a first structure, a platform and a second structure from bottom to top;
the wind direction angle change correction coefficient eta (theta) is expressed as a fitting function
Wherein y is 0i 、x ci 、w i 、A i Fitting parameters are respectively adopted;
wherein i represents the ith section of the landscape tower;
the wind direction angle change correction coefficient η (θ) is calculated with θ=195° as a reference, and the correction coefficient value at other wind direction angles is calculated.
In one embodiment, in step S1, the natural frequency n of the landscape tower is determined first 0 Average wind speed at 10 meters height, in the terrain roughness classThe overall height H of the landscape tower and the structural width of the landscape tower;
and determining a roughness coefficient k and a roughness index alpha of the ground related to the ground surface according to the category of the roughness of the ground.
In one embodiment, the post-correction gust load factor G * The expression of (θ) is
In the formula g p The value range is 3.4-4.4 for the displacement peak factor;
k is a ground roughness index determined according to a load specification, and K=16k is given to take a value of 0.08 for open terrain;
beta is critical damping ratio;
C eH for the exposure coefficient of the top of the landscape tower, for the structures on open terrain, the calculation formula isWherein H is the total height of the landscape tower;
b is the background turbulence coefficient, and the calculation formula isWherein w is the effective width of the windward side of the landscape tower and is->Wherein w is i At a height h i A width perpendicular to the wind direction;
s is a scale reduction coefficient, and the calculation formula isWherein n is 0 Is the natural frequency of the landscape tower->Is the average wind speed at the top of the landscape tower,/-for the landscape tower>
F is the energy ratio of the gust,
in one embodiment, the average wind loadBy generalized mean wind load->Equivalent calculation, generalized mean wind load +.>Is that
In the method, in the process of the invention,and the average wind pressure near the top of the landscape tower is shown, and alpha is the ground roughness index.
In one embodiment, the landscape tower is a steel structure building, the landscape tower comprises a spiral stair with a vertically arranged lower part, a platform is arranged at the top of the spiral stair, a spiral ribbon structure is vertically arranged on the platform, and a thin-wall hollow sphere is arranged at the upper part of the ribbon structure;
in the step S1, the width W of the spiral stair is used as the structural width of the landscape tower;
in one embodiment, the displacement peak factor g p The value is 3.5.
Compared with the prior art, the invention has the beneficial effects that: aiming at the landscape tower with the shape changing along the height, the method given by the existing load specification is corrected by considering the wind direction angle changing factor, and the design wind load calculating method closer to the actual wind load is provided.
Drawings
FIG. 1 is a schematic flow chart of a computing method of the present invention;
FIG. 2 is a schematic diagram of a structure of a spiral landscape tower;
FIG. 3 is a schematic illustration of a constant profile landscape tower calculation model;
FIG. 4 is a photograph of a wind tunnel test model, wherein: (a) A aeroelastic model, (b) a tower upper rigid segment model;
FIG. 5 is a simulated wind tunnel interior airflow conditions, wherein: (a) average wind speed and turbulence; (b) wind speed power spectrum;
FIG. 6 is a wind direction angle definition of a wind tunnel test of a pneumatic elastic model;
FIG. 7 is an average value of the forward wind displacement of the A1 measuring point;
FIG. 8 is a graph of Canadian specifications, model wind tunnel tests, and gust load factor comparisons determined in accordance with the present invention, taking into account wind direction angle change correction factors;
FIG. 9 is a calculation flow of wind load for a spiral landscape tower design.
Detailed Description
The invention is further described below with reference to examples and figures.
A method for calculating the design wind load of a twisted column spiral Liang Jingguan tower based on a GLF method, wherein the appearance and the mass distribution of the landscape tower are unevenly changed along the height, as shown in figure 1, comprises the following steps:
s1, determining related parameters of a landscape tower structure, related coefficients of the roughness of the ground and a wind condition reference coefficient;
s2, calculating based on Gust Load Factor (GLF) method according to load specificationGust load factor G and average wind load of building with unchanged profile in height direction
The height of the building with the shape unchanged along the height direction is the same as the height of the landscape tower, and the width is consistent with the width of the main structure of the landscape tower;
s3, introducing a wind direction angle change correction coefficient eta (theta) to correct the wind load factor G to obtain a corrected wind load factor G * (θ)，
G * (θ)＝G×η(θ)，
Wherein the wind direction angle change correction coefficient η (θ) is determined based on the profile of the landscape tower;
s4, using the corrected gust load factor G * (theta) calculating the corrected static equivalent wind loadAs design wind load, static equivalent wind load +.>The calculation expression of (2) is +.>
When calculating the wind direction angle change correction coefficient η (θ), the correction coefficient value at other wind direction angles is calculated with θ=195° as a reference. That is, the corrected gust load factor value at θ=195° corresponds to the gust load factor which is initially calculated according to the load specification.
The load specification may be Canadian (NR 24-28/2015E, 2015). Average wind loadBy generalized mean wind load->Equivalent calculation。
Taking a spiral landscape tower as an example, the principle and accuracy of the method are described through wind tunnel tests and numerical calculation.
As shown in fig. 2, the spiral landscape tower is a steel structure building, the landscape tower comprises a spiral stair vertically arranged at the lower part, a platform is arranged at the top of the spiral stair, a spiral ribbon structure is vertically arranged on the platform, and a light thin-wall hollow steel ball is arranged at the upper part of the ribbon structure. The spiral stair consists of an arc-shaped box girder and a anticlockwise torsion steel box column, the platform consists of a box girder framework, and the ribbon is a lattice system consisting of two box girders and a box girder connected in the middle.
Derivation of design formula of wind load factor of constant-profile landscape tower array
For a constant profile landscape tower, its mass and wind-blocking area are constant along the height, as shown in fig. 3. In the figure, H is the total height of the landscape tower, W is the width of the landscape tower with unchanged appearance, and M 1 (x 1 ,z 1 ) And M 2 (x 2 ,z 2 ) Is any two points in space.
1.1 gust load factor derivation based on GLF method
Based on the principle of wind induced response analysis in the frequency domain, the gust load factor G is defined as the ratio of the structural peak displacement response to the average displacement response, namely:
in the peak displacementComprising mean wind displacement->And pulsating wind displacement->g p As a shift peak factor, sigma y1 Is the displacement root mean square value.
According to the wind gust load factor G of the formula (1), the total static equivalent wind load of the structural design can be obtained
In the middle ofIs the average wind load.
Average wind response
First, assuming that the landscape tower only counts the influence of the first vibration mode and assuming that the first vibration mode is a straight line shape, the first-order vibration mode coefficientCan be expressed as:
in the formula, xi is the relative height,z is the ground clearance height, and H is the landscape tower height. Assuming that the mass distribution along the height of the landscape tower is m (xi), the generalized mass of the 1-order vibration mode is +.>Expressed as:
if usedRepresents the average wind pressure near the top of the landscape tower,the wind force at the relative height ζ is:
wherein α is a floor roughness index.
From general statics equation, the average wind load is generalizedThe method comprises the following steps:
k for generalized stiffness if the landscape tower corresponds to the first mode * Representing the displacement response of its average windThe method comprises the following steps:
wherein omega is 1 Is the undamped natural circular frequency of the first mode.
Dynamic response of pulsating wind
The response of the landscape tower caused by the action of the pulsating wind load can be solved in the frequency domain based on the random vibration theory. The wind power spectrum corresponding to the j-th vibration mode is as follows according to the random wind vibration theory:
in the formula, coh (eta, eta ', n) and Coh (zeta, zeta', n) are respectively coherence functions of the pulsating wind speed at any two points on the windward side of the landscape tower, and the expressions are respectively:
in addition, S p (n) is a pulsating wind pressure spectrum; n is the pulsating wind frequency;the j-th vibration mode; η, η' is the relative width, +.>Wherein x, x' are the horizontal distance to the landscape tower edge, and W is the horizontal width. Wherein the pulsation wind pressure spectrum and the wind speed spectrum S v The following relationship exists between (n):
in the method, in the process of the invention,the average wind pressure at any height xi, xi'; />Is the average wind speed at any altitude ζ, ζ'. The wind speed spectrum proposed by Davenport is adopted, is irrelevant to the space position, and has the following specific expression:
where k is the surface roughness coefficient,is the variance of the fluctuating wind speed,/>Is the average wind speed at 10m height; omega 10 Is the average wind pressure at a height of 10 m.
If only the first mode is considered, equations (3) and (12) are substituted into equation (9), and the result is obtained:
in the method, in the process of the invention,the average wind pressure at the top of the landscape tower; />Is the average wind speed at the top position of the landscape tower. />Obtained from the average wind speed at the top of the landscape tower, and the top average wind speed can be obtained from the average wind speed at the reference height of 10m + ->Obtained by->Is the climatic statistics of the land. The method is obtained by the following relation:
in the formula (17), there is the following exponential relationship:
after the substitution formulas (18) and (19) are combined, the following integral relationship can be obtained:
finally, the wind spectrum corresponding to the first vibration mode can be written as:
according to the random vibration theory, the displacement response corresponding to the first vibration mode of the landscape tower is obtained as follows:
substituting formula (23) into formula (24), and letting:
wherein H is 1 (in) is the frequency response function of the landscape tower 1-order mode; n is n 1 Is the first natural frequency; beta is critical damping ratio, and the steel frame structure suggests a value of 0.01. The root variance of the displacement can thus be calculated as follows:
and then can obtain:
the integration result of formula (28) can be divided into A 1 、A 2 The expressions are as follows:
where k is a roughness coefficient related to the earth surface, the former represents the resonance influence and contribution of the displacement response, and the latter represents the background portion of the displacement response, as can be seen from equation (29) and equation (30).
Thus, formula (28) can be written as:
1.2 constant profile landscape tower wind gust load factor
The computational model is simplest when the profile of the landscape tower is unchanged along the height, i.e. the mass and the wind-break area are unchanged along the height. Here, a gust load factor definition G consistent with the specification definition is introduced:
the combination of (29) and (30) may be the same as the A 1 、A 2 The expression is as follows:
wherein B, s and F are respectively the background turbulence coefficient, the scale reduction coefficient and the wind gust energy ratio, and the calculation formulas are respectively as follows:
in the method, w is the effective width of the windward side of the landscape tower,wherein w is i At a height h i The effective width of the landscape tower with the unchanged appearance is the structural width W; n is n 0 Is a natural frequency; />Is the average wind speed at the top of the landscape tower,/-for the landscape tower>Wherein->Is the average wind speed of 10 meters in height.
Let k=16k, there isSubstitution (32) can be obtained:
in the formula g p The value range is 3.4-4.4 for the displacement peak factor, and the recommended value of the landscape tower is 3.5; k is the roughness coefficient of the ground, and is 0.08 for open terrain; c (C) eH For landscape tower top exposure coefficients, for structures on open terrain, the following can be calculated:
the formula (40) is that the load specification (NR 24-28/2015E, 2015) calculates a dynamic sensitive structure gust load factor expression, which shows that the gust influence factor of the load specification is applicable to the landscape tower with unchanged appearance.
Deducing a design formula of actual landscape tower gust load factor by combining wind tunnel test
The ideal situation where the landscape tower profile is unchanged along the height is discussed above, however, such a form of construction is rare. The appearance and the mass distribution of the spiral landscape tower of the embodiment are unevenly changed along the height. Furthermore, the frontal area will vary at different wind angles. Wind tunnel test is carried out on the landscape tower, wind vibration response of the landscape tower is measured by adopting a pneumatic elastic model, the wind gust load factor G is calculated according to test data, the accuracy of the G value calculated by Canadian load specification is tested by combining the test data, a correction method is provided, and finally a design formula of the actual wind gust load factor of the landscape tower is determined.
2.1 wind tunnel test study of landscape tower
Modeling and wind field simulation
The upper structure of the landscape tower comprises a sphere, a ribbon and a platform at the top of the tower, and the total height is 25.66m. The lower part is the whole spiral stair with the height of 38.10m (shown in figure 2). The test is carried out in TK-400 DC wind tunnel laboratory of Tianjin water engineering college, the scale of the wind tunnel laboratory is 15m multiplied by 4.4m multiplied by 2.5m, and the test wind speed is continuously adjustable from 0 to 30 m/s. According to the requirements of laboratory scale and model blocking ratio less than 5%, the geometric similarity ratio lambda of the aeroelastic model L ＝L m /L p =1/50, where L is geometry; lambda is the similarity ratio; subscripts m and p are the scaled aeroelastic model and prototype, respectively. The total height of the prototype tower of the landscape tower is 63.76m, and the height of the pneumatic elastic scale model is 1.28m. Determining mass similarity ratio lambda based on inertial force similarity criteria m ＝(λ L ) 3 =1/125, where m is mass. The landscape tower is a sharp-edge structure with obvious separation points, the configuration change is small under the action of gravity, and Reynolds, froude number similarity criteria can be ignored in model design. Thus, the frequency similarity ratio is not the only value, and the design of the aeroelastic model is more flexible. In addition, the design of the landscape tower aeroelastic model also needs to meet the requirements of Strouhal number, cauchy number, density ratio and zeta.
When manufacturing the railing and stair surfaces of the landscape tower, acrylonitrile-butadiene-styrene (ABS) plastic is used to make pneumatic garments to meet the aerodynamic profile similarity requirements. In addition, the handrail and stair surface are cut and separated by a specific distance to prevent the pneumatic garment from forming a single unit, providing additional rigidity and damping to the structure. The lead plates are uniformly arranged on the surface of the stairs to ensure that the model meets the quality similarity ratio. Lead sheets are uniformly arranged on the stair surface, so that the model is ensured to meet the quality similarity ratio. The model stress skeleton is made of steel materials consistent with the actual structure, and the similarity of aerodynamic appearance is met. The finished aeroelastic model is shown in fig. 4 (a).
And (3) carrying out free vibration test and weighing on the completed landscape tower model under manual excitation, and analyzing the acceleration time course of the tower top to determine the fundamental frequency, the first-order damping ratio ζ and m of the model to be 5.407Hz, 0.022 and 2.930kg respectively. Furthermore, the values of 0.329Hz, 0.020 and 2.912kg were compared to the corresponding values of the prototype structure determined by the finite element model FEM. Zeta has a relative error of 9.1% and mass has a relative error of only 0.6%. The comparison result shows that the aeroelastic model meets the test requirement. In addition, it can be confirmed that the frequency similarity ratio lambda n ＝n m /n p =16.43, where n is frequency. According to the Strouhal number similarity criterion, the wind speed similarity ratio lambda v ＝λ n λ L =0.33, where v is wind speed. According to the dimension relation, the acceleration similarity ratio lambda a ＝λ L ·(λ n ) 2 =5.40, where a is acceleration. The same structural material and fine manufacturing process make the zeta value of the model and the prototype the same, the damping similarity ratio lambda ξ =1. The similarity ratio of the reduced scale model is shown in Table 1 according to the requirement of the similarity ratio
TABLE 1 similarity ratio of reduced scale models of landscape towers
The wind tunnel laboratory test section simulates a class B landform turbulent wind field with the proportion of 1/50 according to the requirements of Chinese load specifications by arranging wedges and multiple rows of distributed coarse elements, and the experimental arrangement is shown in a figure 4 (B), wherein the class B landform is usually a suburban landform with sparse houses. Average wind speed v (z) and turbulence in the specificationDegree I z The expression (z) is as follows:
wherein alpha is a ground roughness index, and the grade B landform takes a value of 0.15.I 10 The value is 0.14 under the B-type landform. The Davenport wind speed power spectrum can be calculated in 1.1 knots (13).
The wind speed power spectrum at the position of the model test, which is in the downwind direction, the average wind speed and the turbulence degree and the corresponding prototype 10m height, is compared with the recommended value of the Chinese specification, as shown in figure 5. The comparison result shows that the simulated wind field meets the standard requirements.
Test condition and measuring point arrangement
In order to calculate the gust load factor of the landscape tower test, the wind tunnel test of the atmospheric boundary layer model is required to obtain the wind-induced response time interval value of the landscape tower. To investigate the effect of changes in θ on G of the landscape tower, θ was defined as 0 ° in the positive x-axis direction and 90 ° in the positive y-axis direction, see FIG. 6. For an asymmetric structure landscape tower, the model of the asymmetric structure landscape tower needs to be rotated for a plurality of times to fully consider the influence of theta. Therefore, the test conditions of θ were 0 ° to 345 ° with 15 ° increments. The design average wind speed at the reference height of the landscape tower 10m is 28.5m/s, the corresponding model wind speed is 12m/s, and thus the test v condition is 12m/s. The wind speed under the above conditions is the average wind speed at model 1 m.
In order to determine the G profile, the measurement point should be arranged at the top position with a large wind vibration response. Thus, a measurement point A1 is arranged at the top sphere position, as shown in fig. 2. Further, a measuring piece of a laser displacement meter in the x direction is attached to the measuring point A1, and the displacement of the spherical body at the top of the landscape tower in the wind direction is determined. The sampling frequency of the laser displacement meter is 1024Hz, and the sampling time is 60s. The average value of the A1 measuring point in-wind displacement under different wind direction angles is shown in figure 7.
2.2 gust load factor analysis based on wind tunnel test
As can be seen from section 1.1, the height-independent G determined by the GLF method can be calculated by the formula (1), and the calculated G of the landscape tower calculated by the formula (1) can be compared with the calculation result of the wind tunnel test as shown in FIG. 8. From the figure, the G of the landscape tower calculated by canadian load specification covers most of the experimental measurements under wind direction angle. However, the tower top test G is larger than the standard value under the wind direction angles of 30-60 degrees and 195-225 degrees, and the standard calculation results under the wind direction angles are unsafe, wherein the maximum difference under the wind direction angle of 30 degrees is 1.216 times of the standard value. Therefore, the influence of the change in wind direction angle on G should be considered when calculating G for a landscape tower with canadian load specifications.
2.3 design formula of actual landscape tower wind load factor
In order to make the G calculation structure of the landscape tower be closer to the actual one, a wind direction angle change correction coefficient eta (theta) of the landscape tower is introduced and considered, so that the method can be used for improving the gust load factor of the landscape tower calculated according to Canadian load specifications. The expression of the wind load factor considering the wind direction angle change correction coefficient η (θ) is as follows:
and obtaining a correction coefficient eta (theta) of the gust load factor G considering the wind direction angle change by adopting a multimodal fitting method. Obtaining distribution of eta (theta) through the wind tunnel test result and the ratio of the gust load factors determined by Canadian specifications, then determining an expression of eta (theta) through a multi-modal fitting method, as shown in a formula (45),
fitting parameter y in 0i 、x ci 、w i 、A i The values of (2) are shown in Table 2.
Table 2 values of fitting parameters
Since the G calculated by the specification substantially coincides with the G at the windage angle of 195 ° determined by the wind tunnel test, the G is corrected based on this angle. For a spiral landscape tower, the calculation flow of the design wind load is shown in fig. 9.
By adopting the method, the G calculated by the specification is corrected and compared with that determined by wind tunnel test, as shown in figure 8. In FIG. 8, G is calculated by the method of the present invention * (θ) has good consistency with the wind tunnel test determination G overall and can cover the maximum and minimum values of the test gust load factor. Therefore, the algorithm of the invention can be used for wind resistance design of the landscape tower.
According to the invention, firstly, the design wind load of the appearance-unchanged landscape tower is deduced based on a GLF method, then the aerodynamic coefficient and wind vibration response of the spiral landscape tower are determined through a wind tunnel test, the gust load factor G of the landscape tower is calculated based on wind tunnel test data, the gust load factor G is compared with G calculated by Canadian load specification (NR 24-28/2015E, 2015), the defect of calculating the gust load factor G based on the existing specification method is found, a wind vibration coefficient correction formula considering wind direction angle change is deduced by nonlinear fitting, the G calculated in specification is corrected by using a wind direction angle change correction coefficient eta (theta), and the wind load of the landscape tower is calculated. The calculation method is more accurate and simple, and is suitable for being popularized to various landscape towers and other tower buildings with the appearance changing along the height.
Finally, it should be noted that the above description is only a preferred embodiment of the present invention, and that many similar changes can be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (4)

1. The method for calculating the design wind load of the bent torsion column spiral Liang Jingguan tower based on the GLF method is characterized by comprising the following steps of:
s1, determining related parameters of a landscape tower structure, related coefficients of the roughness of the ground and a wind condition reference coefficient;
s2, calculating the gust load factor G and the average wind load of the building with unchanged appearance along the height direction based on a Gust Load Factor (GLF) method according to the load specificationThe height of the building with the shape unchanged along the height direction is the same as the height of the landscape tower, and the width of the building is the same as the structural width of the landscape tower;
s3, introducing a wind direction angle change correction coefficient eta (theta) to correct the wind load factor G to obtain a corrected wind load factor G * (θ)，
G * (θ)＝G×η(θ)，
Wherein the wind direction angle change correction coefficient η (θ) is determined based on the profile of the landscape tower;
s4, using the corrected gust load factor G * (theta) calculating the corrected static equivalent wind loadAs design wind load, static equivalent wind load +.>The calculation expression of (2) is +.>
The landscape tower comprises three sections, namely a first structure, a platform and a second structure from bottom to top;
the wind direction angle change correction coefficient eta (theta) is expressed as a fitting function
Wherein y is 0i 、x ci 、w i 、A i Fitting parameters are respectively adopted;
wherein i represents the ith section of the landscape tower;
the wind direction angle change correction coefficient eta (theta) takes theta=195 DEG as a reference, and calculates correction coefficient values under other wind direction angles;
in step S1, the natural frequency n of the landscape tower is determined first 0 Average wind speed at 10 meters height, in the terrain roughness classThe overall height H of the landscape tower and the structural width of the landscape tower;
determining a roughness coefficient k and a roughness index alpha of the ground, which are related to the ground surface, according to the category of the roughness of the ground;
corrected gust load factor G * The expression of (θ) is
In the formula g p The value range is 3.4-4.4 for the displacement peak factor;
k is a ground roughness index determined according to a load specification, and K=16k is given to take a value of 0.08 for open terrain;
beta is critical damping ratio;
C eH for the exposure coefficient of the top of the landscape tower, for the structures on open terrain, the calculation formula isWherein H is the total height of the landscape tower;
b is the background turbulence coefficient, and the calculation formula isWherein w is the effective width of the windward side of the landscape tower and is->Wherein w is i At a height h i A width perpendicular to the wind direction;
s is a scale reduction coefficient, and the calculation formula isWherein n is 0 Is the natural frequency of the landscape tower->Is the average wind speed at the top of the landscape tower,/-for the landscape tower>Wherein->An average wind speed at a height of 10 meters;
f is the energy ratio of the gust,
2. the method for calculating the design wind load of the bent-strut spiral Liang Jingguan tower based on the GLF method according to claim 1, wherein the method comprises the following steps: the average wind loadBy generalized mean wind load->Equivalent calculation, generalized mean wind load +.>Is that
In the method, in the process of the invention,and the average wind pressure near the top of the landscape tower is shown, and alpha is the ground roughness index.
3. The method for calculating the design wind load of the bent-strut spiral Liang Jingguan tower based on the GLF method according to claim 1, wherein the method comprises the following steps: the landscape tower is a steel structure building and comprises a spiral stair, wherein the lower part of the spiral stair is vertically provided with a platform, the platform is vertically provided with a spiral ribbon structure, and the upper part of the ribbon structure is provided with a thin-wall hollow sphere;
in step S1, the width W of the spiral stair is taken as the structural width of the landscape tower.
4. The method for calculating the design wind load of the bent-strut spiral Liang Jingguan tower based on the GLF method according to claim 1, wherein the method comprises the following steps: shift peak factor g p The value is 3.5.
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CN109558680A (en) * 2018-11-30 2019-04-02 福州大学 Bridge multiple target equivalent static wind load calculation method based on POD technology
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CN109558680A (en) * 2018-11-30 2019-04-02 福州大学 Bridge multiple target equivalent static wind load calculation method based on POD technology
CN114861451A (en) * 2022-05-23 2022-08-05 国网福建省电力有限公司经济技术研究院 Typhoon-resistant design method for tower in coastal region

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