Could you imagine Johannesburg without the Sentech Tower? The Sentech Tower stands tall in Brixton. It is a landmark recognized throughout the city. It is also known as the Albert Hertzog Tower and Brixton Tower.
Its history is quite interesting. Construction began in 1961. It finished in 1962. The Sentech Tower was once the tallest structure in Africa. That was until the Hillbrow Tower surpassed it.
The Sentech Tower cost R300000 to build. Today it would cost around R300 million.
Ove Arup and Partners designed it. Christiani and Nielsen SA built it. The first transmission happened on 22 December 1961. Today, Sentech broadcasts 18 FM programs. It also broadcasts seven TV stations.
Initially, the tower only transmitted FM radio. Television transmissions started in the 1970s. Later, it became a digital terrestrial television test site.
The Sentech Tower is a cantilever structure. It has a reinforced concrete shaft. It can lean up to 2 meters in strong winds. The tower can withstand winds up to 200 km/h. Its foundation is 2 meters deep and 6 meters wide. The base has a 26-meter diameter. Impressive isn’t it?
The tower’s full height measures 237 meters. Some sources say it’s 234 meters. The 53-ton steel mast was added in just three weeks. The entire structure weighs 7820 tons. The foundation used 1340 tons of concrete. The tower itself used 5684 tons. Reinforcement includes 300 tons of steel bars.
The Sentech Tower’s location is ideal. It stands on Jeppestown shale. This type of shale is brittle but strong under pressure. This makes it great for carrying heavy loads.
Earthquakes are imperceptible inside the Sentech Tower. Its shape makes it immune to tremors. Lightning protection is comprehensive. It uses connections to the mast, steel, lift shaft, and ground. During storms, lightning strikes it multiple times.
Until 1982, observation decks were open to the public. They closed due to security concerns. There were fears of anti-apartheid activists targeting the tower. Sentech’s chairman has expressed interest in reopening them.
From the top, the Sentech Tower offers great views. You can see northern suburbs. Mine dumps lie to the south. The city center is to the east. You can view Soweto and Soccer City to the southwest. On clear days, the Magaliesberg is visible to the north.
The Sentech Tower needed concrete rehabilitation. This project prolonged its lifespan. Workers repaired and protected the concrete. They also replaced windows. New handrails were installed. Port holes were closed. The rotunda roof slab was waterproofed.
Access was difficult. Workers used landing platforms and suspended platforms. A monorail aided movement around the tower. Weather greatly affected progress. Work stopped during rain and lightning within 16km. High winds also caused delays.
The Sentech Tower stands as a symbol. It represents innovation and resilience. It connects the city. It broadcasts information. It remains an iconic part of Johannesburg’s skyline.