Day 38 – There must be a better way

24 Oct

I’m fascinated by the sidewalks in Berlin. I’ve become very familiar with them because of all the walking I’ve done during my time here. Aside from admiring their beauty, I’ve mostly been wondering if they are better than the ones we have in Ottawa. I don’t think this is an easy question as there are many factors that have to be taken into account. And while I have not done any formal research, I have had a lot of time to think about the problem. Here is what I have so far:

The requirement is to provide a system that will enable pedestrians to safely navigate the city on foot. This system must be cost effective to install / maintain and it must not drastically alter the aesthetic of the city.

It think that about sums up the why and the how. Now the system in question will include crosswalks and signal lights and all that stuff, but this does not interest us – right now. Today we are going to focus on the physical sidewalks – specifically the German “decision” to use pavers / stones and the Canadian “choice” of concrete slabs.

Note: I put “decision” and “choice” in quotation marks because I do not think the city planners actually sat down and weighed all their options. All of this happened so long ago there was probably a convention in place for some similar requirement and they simply modified it to address the new problem. And once they started doing it that way it just stuck. There would have been changes over the years but they would have been incremental improvements on the existing system. There would not have been a complete overhaul – the sunk-costs would have been too high.

Now, I don’t have any pictures of the Canadian sidewalks so we will have to make due with my drawerings. Back home sidewalks are made of concrete slabs that are about 1.5 m x 1.5 m. I’m not sure of the thickness. Each slab is poured on site and separated by an expansion joint to prevent damage from changes in temperature. I figure they need to be rated for about plus forty to minus forty degrees Celsius – welcome to Ottawa. Some times the slabs go right to the curb, other times there is a section of grass separating the two.

In Germany they have a similar system but it’s way different. The main waking area is made of two types of pavers. The centre is all squares and the edges are house-shaped. Between the sidewalks and the buildings / curbs there are these cube-shaped stones.

I’m going to list the things I’ve observed about the German system and contrast it with what we have back home. I would like to preface all this with the following: in the past year or so the sidewalks in front of my house had to be dug up twice – once by the phone company (about 10 slabs) and once by the gas company (two slabs). It’s my understanding that this is a common occurrence. Many utilities that were once above ground are now buried. As we start to see fibre-to-the-home, this will happen even more. The point is that sidewalks are not fire-and-forget – there is a lot of maintenance involved.

1. Re-use-ability of the Materials.

The removal of a slab sidewalk is a destructive process – the slab cannot be reused. The paver sidewalk is made up of many small pieces and can be disassembled and reused after the job is complete.

2. Appearance

This one is tough because it’s subjective. I think pavers look nicer but that’s just me.

3. Ease of Maintenance

To remove a slab you need many men and much equipment – a jackhammer to smash it up, a truck to haul the pieces away, and if the pieces are too heavy you will need a backhoe to lift them. To rebuild you need a cement truck and often times good weather – pouring cement in a rain storm can’t be good for the finished product.

Contrast that with pavers. A single worker with a few simple, manual tools can remove an equivalent sized area with much less effort as well as reassemble everything when the work is done.

The tools

Depending on the complexity of the job, a wet-saw might be needed. Even so, you could fit all of this gear in the trunk of your Volkswagen Golf.

He said it would take him less than two hours to complete this section.

4. Use-ability (personal preference)

As someone who used to skateboard, I hate the expansion joints on slab sidewalks.

With pavers it is possible to have an almost continuous smooth surface for unobstructed ollies and kick-flips.

5. Reliability

Even with expansion joints slab sidewalks are prone to cracking.

Because of their smaller size, pavers are much less likely to break then their larger concrete cousins.

6. Initial Cost

I have no idea which costs less for the initial installation. I would be interested to know the following:

  • which takes longer to install – my guess is pavers because they are installed by hand

These guys were working on this job for a while (weeks)

  • which uses more manpower – my guess is again pavers for the same reason
  • which costs more to install – I think slabs because more equipment is needed and the cement has to be mixed on an as-needed basis. With pavers you can have a centralized factory making the bricks and after that it’s just shipping / and storage. With cement you have all this plus the added cost of the extra step of mixing the cement. Plus there could be delays if all the cement trucks are rented for the day. And if you are working on a busy street you have to put the cement truck somewhere.
  • which costs more to maintain – slabs no question (see the above sections on Maintenance, Re-usability, and Reliability)
  • which system is more efficient with with non-standard installations – I think the pavers / cubes system is more flexible as less specialization is required.

Pretty neat, eh?

7. Other

There are many other factors that would need to be investigated if the German system were to be implemented in Canada. The main thing I can think of is the pavers would have to have the surface roughed up. The ones over here are pretty slick. This would not be good in the Canadian winter. Or spring. Or fall. Maybe the summer. Also Canada has more extreme temperature and weather. This would all have to be tested.

Another problem is that the utility companies are the ones that spend the most money digging up the sidewalks but it is the city that decides on the type of sidewalk. Like I said before, it’s a complicated problem.

Anyway, I for one, am very excited to visit another German city. I’m really curious to know if this is just a Berlin thing. As soon as I get to Hamburg I’m going to check if they have the same type of sidewalks as we do here. I can’t wait.

Looks like Munich has a similar system but without the house-shaped edge pieces.

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