Análisis de guyed mástil de celosía de acero sometido a cargas ambientales

cuatro torres de comunicación de hierro / tubo ángulo patas
enero 12, 2019
Directrices sobre las especificaciones técnicas Torre de comunicación
enero 21, 2019

Análisis de guyed mástil de celosía de acero sometido a cargas ambientales

Análisis de guyed mástil de celosía de acero sometido a cargas ambientales

mástiles de celosía de acero se encuentran entre las estructuras de soporte de carga más eficientes en el campo de la construcción de gran altura. El análisis no lineal de un mástil de celosía de acero guyed se lleva a cabo usando el SAP 2000 programa de elementos finitos para diferentes valores de espesor de hielo en 1500 m de altitud. Después de definición del modelo geométrico y cruz- propiedades de la sección, Se analizan diversas combinaciones de carga. Finalmente, la velocidad del viento- se obtiene la relación de espesor de hielo, y la velocidad máxima del viento que la estructura puede resistir se determina para diferentes espesores de hielo.

  1. Introducción

Lattice mast is a general name for different kinds of steel masts.A lattice mast or truss mast is a freestanding framework mast. These structures can be used as transmission masts especially for

voltages of more than 100 kilovoltios, as radio masts (self-radiating masts or carriers for aerials), or as observation masts for safety purposes. Big and heavy frame sections are not required in these

masts. This is why they are lighter than other mast types, and the modules can easily be connected to one another.

Steel lattice masts have been used for many years in the countries where the ice and wind loads are considerable. This is due to increasing demands of modern industry with regard to communication and energy. There are different styles of masts on which small wind generators are mounted: freestanding, guyed lattice, and tilt-up. Freestanding masts are relatively heavy duty, and they stay upright without the help of guy cables. Guyed lattice masts use guy cables to anchor the mast and keep it upright using a relatively small quantity of concrete. Cables stretch from three points near the top of the mast to the ground at some distance from the base of the mast. These constructions are quite light compared to freestanding masts, and therefore constitute the least expensive means for supporting a wind turbine. sin embargo, they require a larger area to accommodate the guy cables.

The technical efficiency and durability of steel lattice masts have increased in recent years. The behaviour of steel lattice masts has been investigated in literature. As the design procedure is significant in these masts, the structural analysis is related to the geometrical model and section properties. Así, the module production and assembly steps, and economic costs, are directly related to the design of masts. Steel lattice masts on land are vulnerable structures. They are mostly affected by environmental loading. Wind loads are the most effective design criteria for these structures. sin embargo, the ice effect must also be taken into consideration, especially at high elevations. In cold regions, these two effects are combined. Por lo tanto, the relationship between the wind and ice must be investigated by conducting proper finite-element analyses to avoid the collapse of such structures. In this paper, the non linear analysis of a guyed steel lattice mast 80 m in height is performed using the SAP 2000 program. While the model is constituted according to TS 648 load conditions are taken from TS 498. The altitude of the structure is taken to be 1500 metro, and the snow region IV is adopted, which is the most conservative option. De este modo, the analysis can also be used for other snow regions. The structure was first analysed without any ice effect. Afterwards, the ice thickness was gradually increased, and the relationship between the wind speed and ice thickness was determined.

  1. Materialand method

Proper sections and angles of the steel lattice mast are first determined. Afterwards, the three dimensional finite element model is given in Figure 1. Top view of the model is presented

in Figure 2. Face sections of the model, showing the distances with angles, are shown in Figure 3 and Figure 4.

Figura 1. 3-re model

 

Figura 2. Parte superior ver

 

 

Figura 3. A y B cara secciones

 

 

Figura 4. C cara section

Mesa 1. Material properties

Material

tipo

Resistencia a la tracción

fuerza

[MPa]

Rendimiento

fuerza

[MPa]

ST52 (S355)

510

360

Mesa 2. section properties

Miembro

tipo

Sección

tipo

Tamaño

[mm]

Columna

miembros

Tubo

48×7

Vertical

miembros

Circular

16

Diagonal

miembros

Circular

16

Guy members

Circular

16

Mesa 3 velocidad del viento y las cargas de acuerdo con la altura

Altura

[metro]

Viento velocidad

“v”

[Sra]

Viento carga

“q”

2

[kg/m ]

0-8

28

50

8-20

36

80

20-80

46

130

A module 3015 mm in length is made of steel members. Columns are placed at an angle of 900 to the ground. Vertical steel members connect columns to one another, and are placed vertically with respect to the columns. Diagonal members are placed by definite angles to the columns, and they also connect the columns to one another. A column with diagonal and vertical members that constitute the module, are shown in Figure 5.

 

Figura 5. Módulo miembros

Guy members and modules are named according to the total height from the ground level. The guy and section numbers, with related heights, are presented in Figure 6.

Mesa 4. propiedades de altura y nieve

Altitud

[metro]

Nieve

región

Nieve carga qs

2

[kg/m ]

1500

IV

176

Mesa 5. Hielo properties

Peso de unidad volumen

[kN / mm ]

7

Existen 26 módulos en el mástil de celosía. La columna, vertical,y miembros diagonales en cada cara del módulo son Figura shownin 7. las direcciones del viento positivos y negativos que afectan a la
módulo también se presentan en la figura.

Mesa 6 propiedades de la sección

 

Miembro

 

Sección

tipo

Sección

tamaño

[mm]

Sección

circunferencia

[cm]

Sección

zona

2

[cm ]

Columna

Tubo

48×7

15.08

9.02

Vertical

Circular

16

5.03

2.01

Diagonal

Circular

16

5.03

2.01

Chico

Circular

16

5.03

2.01

Columna

Tubo

48×7

15.08

9.02

Vertical

Circular

16

5.03

2.01

Diagonal

Circular

16

5.03

2.01

Chico

Circular

16

5.03

2.01

Columna

Tubo

48×7

15.08

9.02

Vertical

Circular

16

5.03

2.01

Diagonal

Circular

16

5.03

2.01

Chico

Circular

16

5.03

2.01

Columna

Tubo

48×7

15.08

9.02

Vertical

Circular

16

5.03

2.01

Diagonal

Circular

16

5.03

2.01

Chico

Circular

16

5.03

2.01

 

 

Load combinations used in the analysis are given in Eqn (1) and Eqn (2) as follows. The combinations are constituted by Snow loads, ice loads according to ice thickness values,

and wind loads effecting different heights of the lattice mast with wind speeds are given in Table 7.

 

Miembro

Nieve

carga

2

[kg/m ]

Repartido

nieve carga

[kg/m]

Hielo

espesor

[mm]

Repartido

hielo carga

[kg/m]

Viento

velocidad

[km / h]

Viento carga conforme a altura

[kg/m]

0-8 metro

8-20 metro

20-80 metro

Columna

 

176

-

 

30

5.15

 

209

12.18

19.49

26.81

Vertical

miembro

4.42

3.03

4.06

6.50

8.94

Diagonal

miembro

4.42

3.03

4.06

6.50

8.94

Chico

4.42

3.03

4.06

6.50

8.94

Columna

 

176

-

 

20

2.99

 

217

12.63

20.21

27.79

Vertical

miembro

4.42

1.58

4.21

6.74

9.26

Diagonal

miembro

4.42

1.58

4.21

6.74

9.26

Chico

4.42

1.58

4.21

6.74

9.26

Columna

 

176

-

 

10

1.28

 

223

12.96

20.73

28.50

Vertical

miembro

4.42

0.57

4.32

6.91

9.50

Diagonal

miembro

4.42

0.57

4.32

6.91

9.50

Chico

4.42

0.57

4.32

6.91

9.50

Columna

 

176

-

 

0

-

 

226

13.14

21.03

28.92

Vertical

miembro

4.42

-

4.38

7.01

9.64

Diagonal

miembro

4.42

-

4.38

7.01

9.64

Chico

4.42

-

4.38

7.01

9.64

efectos carga lateral miembros. carga de nieve distribuida se calcula teniendo en cuenta la superficie superior de los miembros.

Deja una respuesta

su dirección de correo electrónico no será publicada. Los campos necesarios están marcados *