What is civil engineering?

Not many people know much about civil engineers and what they do. They might know that they build bridges and tall buildings but they rarely appreciate exactly how much our lives - and civilisation itself - depends on civil engineering. Much of it we think about - either because we can't see it, or because it works so well we take it for granted.

At the most basic level civil engineering is about providing people with clean water, shelter and sanitation. These things are fundamental to human life and arguably civil engineers have saved more lives than the medical profession.

...but it's more than just that. Civil engineering covers a huge array of disciplines as this video from the Institution of Civil Engineers shows.



You might be thinking, "but what has this got to do with timber?" Well quite a lot as it happens. Timber is one of the few renewable building materials and it becoming increasingly important for larger construction projects as well as for building homes. For this reason, civil engineering degrees are now more likely to include timber as well as steel and concrete (especially the courses we run at Napier). But civil engineering is also needed to create and maintain forests, to prepare the ground, ensure the right amount of water in the soil, and to provide access roads and bridges. In fact, if you've not watched the firrs DVD, you might be surprised to learn that the Forestry Commission employs civil engineers.

why wood : what wood

Last week I gave a presentation it the Institute of Materials, Minerals and Mining in London, which was part of their Materials and Design Exchange (MADE). This was intended as an introduction to wood as a material and used some of the videos made for the firrs project. You can download a pdf copy of my presentation, with a few notes on what I said, here.

Is it wood, is it bricks or is it lego?

Time to practice your French with this post. One of the big new things coming over from continental Europe is "massive wood construction". This is an extension of the idea of a traditional log cabin - in which the walls are solid wood - but updated with modern hi-tech manufacturing methods. So instead of irregular round logs you have nice regular building blocks.

This provides very good insulation keeping the heat in and the noise from outside out. It's also greener than conventional fired clay bricks - which require more energy to make and produce more carbon dioxide in the process.

Obviously it requires an awful lot of wood, but the good thing is that cheaper, low quality, wood can be used. As there is so much of it, the force is shared over a bigger area, meaning it doesn't have to be nearly as strong or as stiff as the wood used in a timber frame building.

You might see this type of construction more often in the next few years for buildings like schools and hotels.

The first video is an explanation (in French) of one particular system of massive wood construction (there are others). Notice the computer controlled robotic cutting and drilling machines. Wood manufacturing really is like this in the 21st century.

The second video, which has no sound, shows the same system being used to actually construct a building. Notice how accurately the pieces fit together thanks to the precision manufacturing.

Careers in the timber industry

The UK's multipurpose forests provide environmentally friendly materials for all sorts of things and there are a vast array of different types of job out there.

For more information on jobs visit The Doorway and A Job In.

Earthquakes

Many people live in places where there is a risk of earthquakes. Timber is a good choice for houses in these areas because wooden construction is able to absorb a lot of movement and energy. Materials like brick and concrete are very stiff and crack easily so it is more complicated to make earthquake resistant buildings from them. Steel bolts and welds can also crack in situations like this.

In most cases the buildings won't actually be designed to survive a big earthquake without any damage at all. The most important thing is for the building to stay standing long enough so that people can get outside. People often choose to build their houses from timber because it makes them easy to repair after a natural disaster.

The first video shows a timber frame building and the second video shows a concrete frame building. Notice how this timber building is able to recover after large movements, whereas this concrete building can't.

Lolly stick bridges

We found loads of videos on the web of people's lolly stick bridge competions - from highschool science classes to engineering students at university...and in every single one people were having a lot of fun!

Now you could do this with lolly sticks (or popsicle sticks as the americans call them), modelling matches (the ones without heads), balsa wood, or with the wooden coffee stirrers you get in fancy coffee shops - you can buy a box of those quite cheaply. For fixings you could use glue, sticky tape, drawing pins, or even string.

Standing on the bridges looks a little bit risky - not least because everyone gets to know how much you weigh. Instead you could be more scientific and hang a bucket of weights off the bridge. The figures in this video are in pounds. There are 2.2 pounds in a kilogram.

There are lots of other things you can do instead of bridges...how about cranes, towers, roofs or even fighting walls. You can even make a lolly stick bridge using no fixings at all - just lolly sticks and nothing else! Maybe one day we'll show you how...

Traditional timber frame 2

Here is a nice contrast to the "traditional timber frame 1" video. Again it's a class of students in the USA, but this time they are using modern machine tools for their carpentry. The most interesting bit is towards the end where you can briefly see some computer controlled robotic saws in action.

Timber frame DIY

It's possible to buy a timber frame kit house and to erect it yourself. Here is a video showing a photo montage of just that. The kit is made of small and light components that can be lifted into position without a crane. Timber frame is a very popular choice for people who build their own homes.

The green stuff is a special membrane that helps the building "breath" - a bit like a gore-tex jacket.

The stages of construction you can see here are:
1) The foundations (which would include all the drainage and other services)
2) Ground floor preparation (to get a nice surface and keep the water out)
3) The walls of the ground floor erected
4) The floor placed on the ground floor walls
5) The upper storey walls erected
6) The roof trusses erected
7) The windows installed
8) The outer brickwork laid
9) The roofing installed

Traditional timber frame 1

This video shows a group of students at a workshop in the USA building a traditional timber frame "post and beam" house using hand tools. Buildings like this are still being made (check out Carpenter Oak in the UK), but only for special projects. They require skilled craftspeople and large pieces of timber so are not practical for everyday houses... but can be very beautiful.

In contrast, a modern timber framed house is usually made from pieces about twenty times smaller in size! ....but that doesn't necessarily mean that a modern house won't last as long. The timber is used in a different way that allows for the forces to be carried by a larger number of smaller pieces. The wood is almost always a softwood like spruce, pine or fir which is dried in a kiln before it's used for building.

In this video it looks like the wood is a softwood, but post and beam houses are also often made from hardwoods like oak. In both cases, the timbers tend to be too big to be dried before use, so the connections must all be made to allow for the timber to shrink as it dries out as the building ages.

Check out "Traditional timber frame 2" to see the same sort of thing, but with modern power tools.

Timber kit timelapse

This video shows a short timelapse of a timber frame house being erected...it looks like this was a demonstration during an exhibition. Many houses are now built like this in the UK. The timber kits are made as wall and floor panels in a factory and transported to the building site on a lorry in the right order for them to be placed on the foundations. A normal sized house can be put together like this in a matter of hours ...but this speed doesn't mean poor workmanship. In fact factory prefabrication (or so called "modern methods of construction") allow much tigher quality control than is possible outdoors on a busy building site.

Normally the house is then clad with brickwork to keep the wind and rain out...protecting the timber as well as the people living in the house. As far as most people can tell, the finished house looks like it is made from bricks.

The video seems to freeze 3 seconds in so you may need to drag the playhead to get it started again.