The Civil Engineering Contractor July 2018 | Page 23

Demolition vs refurbishment “Demolition projects are generally associated with forward-planning and safety management. Clients would typically opt to have a redundant section of their plant demolished to make way for expansion or growth,” Bester says. “Alternatively, the cost of demolition compared to the maintenance and upkeep of a redundant structure may result in the demolition of the structure as part of the client’s eventual plant-closure planning. “We are also seeing an increase in structures deteriorating beyond the point of repair due to lack of maintenance. We will almost always encourage the demolition of those types of structures before they reach the point of becoming a risk to others.” Almost a third of the buildings in Johannesburg’s CBD deserve to be condemned and demolished, if only government had the budget, says Richard Kelly, technical director at Wreckers Dismantling. “Concrete only has a certain lifespan, after which it becomes a hazard,” he says. That lifespan depends on the strength of the concrete, but he explains, for example, that many bridges and buildings in South Africa date from the 1950s and 1960s and consequently, cases of concrete cancer are common. He believes that refurbishment is not an option in such cases. “At most, these structures would only have a 10-year lifespan left, even after expensive renovation.” Sometimes, infrastructure can be demolished much sooner than anyone could predict. Occasionally, major infrastructure has a built- in obsolescence: when South Korea built a brand new Olympic stadium in Pyeongchang to host the 2018 Winter Games, the USD109-million 35 000- seat stadium was only ever meant to be used four times before it would be demolished. That cost amounts to an astonishing USD10-million an hour of use. It was built to be obsolete: the county in which the stadium is situated has only 40 000 people, and once all the competitors and guests had left, the stadium would be useless for locals. In fact, this scenario is rather typical for Olympic events, and even in the case of South Africa’s hosting of the 2010 FIFA Soccer World Cup. Judging by poor attendances at top-flight games that do not involve the country’s two most popular clubs, Kaizer Chiefs and Orlando Pirates, it appears government spending more than R9-billion on stadiums alone was a resounding waste of money. The absence of fans at football matches has given affected municipalities that own the stadiums a huge headache, as maintenance costs drain city coffers with little income to offset that expenditure. Would K ate Bester, contract manager at Jet Demolition, says, “The industry has come a long way since the days of ball-and-chain demolition, and is now a profession built on trust, experience, and proven ability.” The question of whether to repair or demolish a structure is likely to become ever more important as the size of South Africa’s infrastructure increases. According to a report titled Infrastructure Insight: South Africa by market research and information service provider Ken Research, the market value of South Africa’s infrastructure increased by around R70-billion during 2010–2015, a trend which is set to continue as it is anticipated to grow another R113- billion by 2020. It predicted that the market value of South Africa’s infrastructure would have more than doubled in just 10 years to R335.3-billion. The report looked at all key infrastructure sectors, including roads, railways, electricity and power, water and sewerage, communication, airports, and ports. In the World Economic Forum’s Global Competitiveness Report for 2015–2016, South Africa (placed 59th out of 140 countries) ranks well ahead of other major African economies in terms of its overall infrastructure quality. Nearest was Algeria at 101, Egypt at 114, and the nearest sub-Saharan competitor was Nigeria, ranked 133. However, the risk with over-emphasis on building new infrastructure at the cost of not adequately maintaining existing infrastructure is that the infrastructure often requires demolition earlier than might otherwise have been the case. TECHNOLOGY When the 68-year-old Mike Perkin began his trade in 1966, it was with a jack hammer and a 14-pound hammer. Explosives weren’t used back then, not even for 30-metre-high chimneys. He learned his trade the hard way — by exercising extreme safety and care as structures were demolished virtually by hand. “Concrete only has a certain lifespan, after which it becomes a hazard. That lifespan depends on the strength of the concrete. Many bridges and buildings in South Africa date from the 1950s and 1960s and consequently, cases of concrete cancer are common.” Richard Kelly, technical director at Wreckers Dismantling demolition be a cheaper long-term option? Kelly says that Wreckers has been involved in a number of demolitions of structures (often just the steel frame) of buildings condemned before they were ever complete: one structure in Nigeria’s Abuja, and another in Tshwane. Types of demolition • Implosion: This i