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What are the advantages of Steel tower w.r.t. Reinforced Concrete (RCC) Poles?
Higher Strength, span and life
Less weight and maintenance
assemble at site
All of these
All of these
Steel lattice towers offer higher mechanical strength, longer span capabilities, and significantly longer operational lifespans compared to RCC poles. They feature lower relative weight for high power capacities and lower maintenance costs over time, while their prefabricated components allow for easy assembly at the site. Thus, all listed advantages are correct.
IS 802 (Part 1/Sec 1): 2015
Steel lattice towers offer higher mechanical strength, longer span capabilities, and significantly longer operational lifespans compared to RCC poles. They feature lower relative weight for high power capacities and lower maintenance costs over time, while their prefabricated components allow for easy assembly at the site. Thus, all listed advantages are correct.
S=8TwL2тАЛ тАФ Sag equation showing relationship between span length (L) and conductor tension (T)
MRтАЛ=╧ГтЛЕZ тАФ Moment of resistance for supporting structure structural cross-section
Steel towers are fabricated using galvanized structural steel angles and members assembled into a lattice framework. This lattice structure efficiently distributes wind, ice, and mechanical line tension loads through axial tension and compression across its members. In contrast, RCC poles rely on concrete mass and steel reinforcement to withstand bending moments, making them much heavier and limited to lower voltage and shorter span applications.
Steel towers are typically used for high voltage transmission lines (66┬аkV and above).
RCC poles are limited to primary and secondary distribution networks (11┬аkV and 33┬аkV).
Lattice towers allow high structural height, increasing ground clearance for extra-high voltage lines.
High structural strength capable of withstanding heavy wind and line loading over long spans (> 300 m).
Longer service life (> 50-100 years) due to hot-dip galvanization.
Sectional structural members enable easy transportation and site assembly in difficult terrain.
Lower overall maintenance cost compared to concrete degradation over time.
High initial capital cost.
Requires a larger footprint and substantial foundation area.
Susceptible to atmospheric corrosion if hot-dip galvanizing coating deteriorates.
High Voltage (HV), Extra High Voltage (EHV), and Ultra High Voltage (UHV) overhead transmission lines.
Long river crossings, hilly terrains, and wide span corridors.
| Feature | Steel Tower | RCC Pole |
|---|---|---|
Typical Span Length | Large (> 300 m) | Small (80 - 100 m) |
Operating Voltage | 66 kV to 765 kV+ | Up to 33 kV |
Transportation & Assembly | Assembled at site from member parts | Pre-cast full length, heavy to transport |
Lifespan | Longer (~100 years) | Moderate (~50 years) |
Option A is correct because steel lattice construction provides high strength-to-weight ratio allowing longer spans.
Option B is correct because prefabricated steel angle members weigh significantly less per unit power carried than massive RCC poles, leading to easier handling and low long-term maintenance.
Option C is correct because steel towers are shipped as light individual angle sections and bolted together directly at the tower footing site.
D is correct тАФ Steel towers exhibit superior strength, support longer spans, have a longer service life, incur lower maintenance, and can be assembled on-site from lightweight components.
In competitive exams, remember that RCC/PCC poles are preferred for low-cost distribution (11┬аkV/33┬аkV) with spans under 100┬аm, whereas Steel Towers are mandatory for EHV lines (>66┬аkV) due to ground clearance and span requirements.