There have been many great feats of architecture in the last quarter century, some that have become truly iconic for marvels in engineering and some that have equally been complete disasters.
Here are our top 5 structural engineering horror stories from around the world.
The Golden Gate Bridge
We start with an iconic landmark known around the world that has been suffering from a serious case of corrosion. Initially, people thought that the bridge could never be built – a structure that would have to be light enough for the hanging cables, but strong enough to withstand the forces of nature – resilient it still stands. However, this was not always the case. Corrosion to the cables from damp weather conditions meant that many of the cables were at risk of snapping. I n 1973 engineers were brought in to replace almost 500 of the cables – requiring regular maintenance henceforth.
John Hancock Tower
Boston’s 240-meter (790 ft) John Hancock Tower was a pioneer in 1970s structural design, save one major engineering problem – exploding windows! The glass was efficient in letting as much sunlight in as possible, but in the process kept out much of the heat, which in turn warped the windows causing the explosions. Engineers quickly installed double-paned panels layered with lead that allowed for the expansion, all at an eye-watering $7 million and five year delay to the project.
Another skyscraper from the 1970’s that did not meet the structural requirements for safety was Manhattan’s Citicorp Centre. The base of the building sits on stilts – prompted by a planning negotiation stating that the building would not encroach on a neighbouring churchyard. However, the stilts were designed to sit central to the building instead of on the sides – this proved to be a gross error in judgement when an observation was made regarding the speed and force of gale force winds. Citicorp was forced to bring in an emergency team to weld all joints of the building secure.
Sydney Opera House
One of the most iconic buildings ever to grace a city skyline – it is hard not to marvel at such an engineering triumph, or so it would seem. During the construction in 1959, a new government came to power and questions over costs arose. Designers had to amend their plans, resulting in the auditorium being too small for an opera acoustically, and the concert hall becoming too large. The Sydney Opera House has since been voted the 18th worst concert hall in the world for acoustics.
The Washington Monument was fraught with problems from the beginning. Originally designed to stand 180 meters tall, the flat-topped pillar would be encased in marble, at its base a circular colonnade and Washington upon the roof. However, there was a mounting problem – the column exerted a pressure of 500 kilopascals on a space of only 7 square meters. The column began to lean 4 centimeters out of alignment with cracks beginning to appear. US Corps of Engineers managed to remodel the structure in 1876 by streamlining the top with a pointed pyramidion, allowing it to stand proud ever since.