Analysis of communication tower with different heights subjected to wind loads using TIA-222-G and TIA-222-H standards

Figures & data

Figure 1. General arrangement of (a) 40, (b) 60 and (c) 80 m high towers.

Figure 2. Modeling and Analysis of a typical communication tower (a) Line model, (b) 3D computer model, (c) Loading applied.

Table 1. Tower weight and solidity ratio.

Tower height (m)			Segment	Level (m)	Ht. (m)	Ht. from ground to centerline of segment (Z), (m)	Solidity ratio (ε)
							Ag (m^2)	Af (m^2)	ε
			1	70–80	10	75	10	2.41	0.24
			2	60–70	10	65	13	3.03	0.23
			3	50–60	10	55	19	3.63	0.19
		80	4	40–50	10	45	25	4.29	0.17
	60		5	30–40	10	35	31	4.92	0.16
40			6	20–30	10	25	37	5.52	0.15
			7	10–20	10	15	43	6.18	0.14
			8	0–10	10	5	49	6.80	0.14

Table 2. Effective projected area (EPA)_S of each tower segment.

Segment	ε	Cf	Af	Df (0°)	Df (45°)	(EPA)S (0°) m^2	(EPA)S (45°) m^2
1	0.24	2.810	2.41	1.0	1.18	6.7731	7.997
2	0.23	2.841	3.034	1.0	1.18	8.6193	10.128
3	0.19	3.018	3.633	1.0	1.14	10.9648	12.537
4	0.17	3.105	4.293	1.0	1.13	13.3289	15.046
5	0.16	3.165	4.917	1.0	1.12	15.5614	17.413
6	0.15	3.209	5.516	1.0	1.11	17.7026	19.682
7	0.14	3.235	6.176	1.0	1.11	19.9800	22.132
8	0.14	3.258	6.8	1.0	1.10	22.1562	24.462

Table 3. Effective projected area (EPA)_A of ladder & cable.

	Ladder (CAxAA)		Cable (CAxAA)		(EPA)A
	W0 0°	W0 45°	W0 0°	W0 45°	W0 0°	W0 45°
	(m^2/m)
Top 10 m (no cage)	0.196	0.108	0.027	0.027	0.134	0.081
Lower part (with cage)	0.377	0.241	0.226	0.320	0.362	0.337

Table 4. Design wind force.

Segment	Kz	on each tower segment			on ladder, cables & appurtenances
		qz (kN/m^2)	(FST)s 0° (kN)	(FST)s 45° (kN)	(EPA)A (0°) m^2	(EPA)A (45°) m^2	F(0°) kN	F(45°) kN
1	1.53	0.84	4.81	5.68	0.134	0.081	0.95	0.58
2	1.48	0.81	5.95	6.99	0.362	0.362	2.50	2.50
3	1.43	0.78	7.30	8.35	0.362	0.362	2.41	2.41
4	1.37	0.75	8.51	9.60	0.362	0.362	2.31	2.31
5	1.30	0.71	9.42	10.54	0.362	0.362	2.19	2.19
6	1.21	0.66	9.99	11.10	0.362	0.362	2.04	2.04
7	1.09	0.60	10.12	11.21	0.362	0.362	1.83	1.83
8	0.87	0.47	8.91	9.83	0.362	0.362	1.45	1.45
		Total force =	65.00	73.31	Total force =		15.69	15.32

Table 5. Design wind force on dishes.

No.	Dia. (m)	Forces on dishes	Forces on tower
		FAM (kN)	Fx (kN)	MN (kN.m)
16	0.42	2.44	2.44	1.22
16	0.42	−1.66	1.66	0.83
1	0.68	0.40	0.40	0.20
Total force =			4.51	2.25

Figure 3. (a) Node interval on one leg, (b) Design wind force on structure, (c) Design wind force on the ladder, cable, and appurtenances, (d & e) Design wind force on antennas, discrete appurtenances.

Figure 4. Leg member forces at wind speed of 125, 225 kph for tower heights 40, 60, and 80 m for (a) Structure Class-I (TIA-222-G), (b) Risk Category-I (TIA-222-H).

Figure 5. Leg member forces at wind speed of 125, 225 kph for tower heights 40, 60, and 80 m for (a) Structure Class-II (TIA-222-G), (b) Risk Category-II (TIA-222-H).

Figure 6. Comparison of forces in leg members for 80 m high tower at basic wind speed of 125 & 225kph for (a) Structure Class-I & II, (b) Risk Category-I & II.

Table 6. Design wind force.

Segment	Kz	on each tower segment			on ladder, cables & appurtenances
		qz (kN/m^2)	(FST)s 0° (kN)	(FST)s 45° (kN)	(EPA)A (0°) m^2	(EPA)A (45°) m^2	F(0°) kN	F(45°) kN
1	1.53	1.34	7.71	9.10	0.134	0.081	1.53	0.92
2	1.48	1.30	9.51	11.18	0.362	0.362	4.00	4.00
3	1.43	1.25	11.69	13.36	0.362	0.362	3.86	3.86
4	1.37	1.20	13.62	15.37	0.362	0.362	3.70	3.70
5	1.30	1.14	15.08	16.87	0.362	0.362	3.51	3.51
6	1.21	1.06	15.98	17.77	0.362	0.362	3.27	3.27
7	1.09	0.95	16.20	17.94	0.362	0.362	2.93	2.93
8	0.87	0.76	14.25	15.74	0.362	0.362	2.33	2.33
		Total force =	104.03	117.33	Total force =		25.12	24.52

Table 7. Design wind force on dishes.

No.	Dia. (m)	Forces on dishes	Forces on tower
		FAM (kN)	Fx (kN)	MN (kN.m)
16	0.42	3.91	3.91	1.96
16	0.42	−2.66	2.66	1.33
1	0.68	0.64	0.64	0.32
Total force =			7.21	3.61

Table 8. Leg Members compressive, tensile, bolt strength, and utility ratios for 40 m high tower.

Block (m)	Angle Size	Code/Standard	Axial load, Pu (kN)	Compressive Strength		Tensile Strength (kN)		Bolt Strength (kN)
				ϕc Pn	Utility Ratio	ϕc Pn	Utility Ratio	ϕ Rnb	ϕ Rnb	Utility Ratio
0–5	HL 3”x3/16”	TIA-222-G	10.89	132	0.08	172	0.06	281	332	0.11
		TIA-222-H	14.06	157	0.09	188	0.07	365	398	0.11
5–10	HL 3” x ¼”	TIA-222-G	43.68	174	0.25	227	0.19	374	332	0.36
		TIA-222-H	56.54	224	0.25	269	0.21	486	398	0.36
10–15	HL 4” x ¼”	TIA-222-G	80.19	265	0.30	332	0.24	374	332	0.65
		TIA-222-H	103.88	321	0.32	385	0.27	486	400	0.65
15–20	HL 4” x 3/8”	TIA-222-G	113.02	432	0.26	487	0.23	842	498	0.61
		TIA-222-H	146.4	530	0.28	636	0.23	1095	598	0.61
20–25	HL 4” x 3/8”	TIA-222-G	146.20	432	0.34	487	0.30	842	498	0.79
		TIA-222-H	189.5	530	0.36	636	0.30	1095	600	0.79
25–30	HL 5” x 3/8”	TIA-222-G	178.31	602	0.30	619	0.29	1053	778	0.62
		TIA-222-H	231.33	715	0.32	858	0.27	1369	935	0.62
30–35	HL 5” x 3/8”	TIA-222-G	208.15	602	0.35	619	0.34	1053	778	0.72
		TIA-222-H	270.28	715	0.38	858	0.32	1369	397	0.72
35–40	HL 5” x 1/2”	TIA-222-G	238.28	792	0.30	812	0.29	1404	778	0.83
		TIA-222-H	209.57	941	0.33	1129	0.27	1825	400	0.83

Table 9. Tower top maximum displacements.

Sr. No.	Tower Height (m)	Structure Class I	Structure Class II	Risk Category I	Risk Category II
		125 kph	125 kph	125 kph	125 kph
1	40	136.44	160	223.52	203.2
2	60	287.02	328.68	452.22	438.15
3	80	424.94	476.76	660.4	622.3

Figure 7. Comparison of leg member forces for 40, 60 & 80 m high tower and Structure Class-I/Risk Category-I at basic wind speed of 225kph.

Figure 8. Comparison of leg member forces for 40, 60 & 80 m high tower and Structure Class-II/Risk Category-II at basic wind speed of 225kph.