Analisis Guyed keluli kekisi mast tertakluk kepada beban alam sekitar

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januari 12, 2019
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januari 21, 2019

Analisis Guyed keluli kekisi mast tertakluk kepada beban alam sekitar

Analisis Guyed keluli kekisi mast tertakluk kepada beban alam sekitar

tiang keluli kekisi pangkat antara struktur menanggung beban yang paling berkesan dalam bidang pembinaan bangunan tinggi. Analisis bukan linear daripada Guyed keluli kekisi mast dijalankan menggunakan SAP 2000 program unsur terhingga untuk nilai ketebalan ais yang berbeza pada 1500 m ketinggian. Selepas takrif model geometri dan salib- seksyen hartanah, pelbagai kombinasi beban dianalisis. akhirnya, kelajuan angin- hubungan ketebalan ais diperolehi, dan kelajuan angin maksimum bahawa struktur boleh menahan ditentukan bagi yang berbeza-beza ketebalan ais.

  1. pengenalan

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 kilovolt, 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. Walau bagaimanapun, 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. Justeru, 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. Walau bagaimanapun, the ice effect must also be taken into consideration, especially at high elevations. In cold regions, these two effects are combined. kebakaran, 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 m, and the snow region IV is adopted, which is the most conservative option. Dengan cara ini, 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.

Figure 1. 3-D model

 

Figure 2. Top pandangan

 

 

Figure 3. A dan B muka bahagian

 

 

Figure 4. C muka seksyen

Jadual 1. bahan hartanah

bahan

jenis

tegangan

kekuatan

[MPa]

hasil

kekuatan

[MPa]

St52 (S355)

510

360

Jadual 2. seksyen hartanah

ahli

jenis

Section

jenis

Saiz

[mm]

Kolum

ahli

paip

48×7

menegak

ahli

Pekeliling

16

Diagonal

ahli

Pekeliling

16

Guy members

Pekeliling

16

Jadual 3 Kelajuan angin dan beban mengikut ketinggian

tinggi

[m]

angin kelajuan

v

[Cik]

angin beban

“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.

 

Figure 5. modul ahli

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.

Jadual 4. Ketinggian dan salji hotel

Altitude

[m]

salji

rantau

salji beban qs

2

[kg/m ]

1500

IV

176

Jadual 5. ais hartanah

Berat badan daripada unit jumlah

[kN / mm³ ]

7

Tiada 26 modul dalam mast kekisi. lajur, menegak,dan ahli pepenjuru dalam setiap muka modul adalah Rajah shownin 7. arah angin positif dan negatif yang menjejaskan
modul juga turut dipersembahkan dalam rajah.

Jadual 6 seksyen hartanah

 

ahli

 

Section

jenis

Section

saiz

[mm]

Section

lilitan

[cm]

Section

kawasan

2

[cm ]

Kolum

paip

48×7

15.08

9.02

menegak

Pekeliling

16

5.03

2.01

Diagonal

Pekeliling

16

5.03

2.01

Lelaki

Pekeliling

16

5.03

2.01

Kolum

paip

48×7

15.08

9.02

menegak

Pekeliling

16

5.03

2.01

Diagonal

Pekeliling

16

5.03

2.01

Lelaki

Pekeliling

16

5.03

2.01

Kolum

paip

48×7

15.08

9.02

menegak

Pekeliling

16

5.03

2.01

Diagonal

Pekeliling

16

5.03

2.01

Lelaki

Pekeliling

16

5.03

2.01

Kolum

paip

48×7

15.08

9.02

menegak

Pekeliling

16

5.03

2.01

Diagonal

Pekeliling

16

5.03

2.01

Lelaki

Pekeliling

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.

 

ahli

salji

beban

2

[kg/m ]

diedarkan

salji beban

[kg/m]

ais

ketebalan

[mm]

diedarkan

ais beban

[kg/m]

angin

kelajuan

[km / h]

angin beban Menurut kepada ketinggian

[kg/m]

0-8 m

8-20 m

20-80 m

Kolum

 

176

 

30

5.15

 

209

12.18

19.49

26.81

menegak

ahli

4.42

3.03

4.06

6.50

8.94

Diagonal

ahli

4.42

3.03

4.06

6.50

8.94

Lelaki

4.42

3.03

4.06

6.50

8.94

Kolum

 

176

 

20

2.99

 

217

12.63

20.21

27.79

menegak

ahli

4.42

1.58

4.21

6.74

9.26

Diagonal

ahli

4.42

1.58

4.21

6.74

9.26

Lelaki

4.42

1.58

4.21

6.74

9.26

Kolum

 

176

 

10

1.28

 

223

12.96

20.73

28.50

menegak

ahli

4.42

0.57

4.32

6.91

9.50

Diagonal

ahli

4.42

0.57

4.32

6.91

9.50

Lelaki

4.42

0.57

4.32

6.91

9.50

Kolum

 

176

 

0

 

226

13.14

21.03

28.92

menegak

ahli

4.42

4.38

7.01

9.64

Diagonal

ahli

4.42

4.38

7.01

9.64

Lelaki

4.42

4.38

7.01

9.64

kesan beban sisi ahli. beban salji diedarkan dikira dengan mengambil kira kawasan permukaan atas anggota.

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