The Arts Centre (Boys High Building)
The Boys High Building in the Christchurch Arts Centre currently houses the Christchurch Visitor Information and provides a great place to start our tour. Now that you have downloaded the PocketSights app, you can make your way upstairs into the collection of little boutiques and gift shops. If you have a look at what is now above your head, you may be able to spot some steel bars arranged in a spoke layout. These are part of the 3-dimensional BRB (buckling-restrained brace) system which has been installed in the building. You will see many more of these (albeit in many different sizes) as you make your way through the central city. They are used to dissipate the energy from an earthquake and are usually positioned so that they can be replaced with ease in case they are damaged.
Christchurch Art Gallery Te Puna o Waiwhetu
This building uses one of the most distinctive base isolations in all of Christchurch. If you enter the Gallery through the main entrance, and then take the elevator down to the underground carpark, you will be able to see lots of colourful columns. And on the top of all of these columns, are thick rubber-collared so-called "triple pendulum base isolators". These essentially separate the building from the ground and foundation. As a result, during a big earthquake, the ground may shake a lot but the building will pretty much remain in the same location. The base isolators are designed such that the building can move 60 cm relative to the ground. If you now come back outside and have a look at the area in front of the art gallery, you might find what is called a seismic gap: the area that separates the base isolated building from the surrounding ground. It is made of a flexibe rubber and smaller, weaker bricks which can move and break if necessary. This allows for the aforementioned 60 cm of movement .
Lane Neave Building
If you wander into the lobby of the Lane Neave building on Cambridge Terrace, you will be able to spot the seemingly boring white steel frames. But not all steel frames are created equal, and this is a special type called a "rocking steel frame". This frame is designed so that when a big earthquake hits, the building can in a way sway backwards and forwards. The frame is made so that it can move a lot without being significantly damaged. In addition to this, you may be able to spot some U-shaped steel bits in the gaps between the steel frame and the wall. These also have a very specific purpose. When the building sways back and forth during a major earthquake, you have to make sure that it doesn't collide with other buildings, or that different parts of the same building collide with each other. These U-shaped steel parts can be squished together and thus prevent the building from damaging itself or surrounding buildings.
BNZ Centre
If you approach the new BNZ centre from the Hereford Street side, you should be able to see some diagonal white pieces of steel on the first floor. This is a relatively "traditional" earthquake technology which has been used for over 30 years. While it was initially used to brace against wind forces, more recent applications have introduced it to the world of earthquake engineering. An eccentrically braced frame is a simple yet effective way of transferring seismic loads within a building and making sure that there is no failure.
PWC Centre Christchurch
This building uses a new earthquake technology which has become all the rage in Christchurch since the earthquakes: buckling-restrained braces (BRBs in short). These are specially designed for earthquakes and have the advantage that they do not buckle (hence the name). As a result, they can take a lot of energy out of the building during an earthquake. If there is any damage inside these BRBs, they can usually be taken out and replaced without too much trouble.
Wynn Williams House
The new Wynn Williams House on Hereford Street uses a whole host of different earthquake technologies. Although some of these are not visible from the outside (like the base isolation, rocking connections and LVL beams), you can spot the metal caps of steel tendons in the facade, which run through all of the beams. These tendons are just special types of rope which are stretched through the beams and essentially work to hold the structure together during an earthquake. Another interesting point to note about this building is the fact that it uses significant amounts of wood. Although they are hidden, the beams are all made of hollow laminated timber. They connect to the concrete columns at each of the points where a steel tendon cap is visible. This gives you a good sense of the overall structure of the building.
Christchurch Arts Centre (Chemistry Building)
If you approach the building from the Hereford Street side, you should be able to see some steel ropes which run through the facade. These are used to anchor and hold together the building. In fact, these were installed before the 2010/11 Canterbury earthquake sequence and quite possibly prevented further damage to the historical buildings.
