Seismic Matters

Wunderlich Park near Woodside

These high dry stone walls near Woodside California which were built before the big earthquake are still in great condition.

The lush foliage of moss and various species of fern makes this wall an especially attractive border enclosing a grassy area around an old stable.

That these walls have lasted so long seems to indicate that they were built right, even though they didn't build them out of concrete.

For centuries the mortar-free construction has proven to be apparently more earthquake-resistant than using mortar. The stones of the dry-stone walls in the pictures above which were built by the chinese workers in California in the late 1800's for example, could move slightly and resettle without the walls collapsing, which should be recognized as an ingenious passive structural control technique employing both the principle of energy dissipation and that of suppressing resonant amplifications. When walls are built correctly (meaning, well-bonded, properly battered, and having good foundations and built sufficiently thick enough ) they can resist seismic movement because of a certain cohesive elasticity.

Twisted Sisters.

The twisted Sketchup preliminary drawing

The real twisted thing, completed yesterday.

Twisted brothers and twisted sisters.

Pillars of the Perverse

Speaking of twisted things, here is a photo I just came across recently of our dry stone helix being built in Garden Hill, Ontario, an unusual structure which I designed and was fortunate enough to have skilled members of the DSWAC ( Reid Snow, Evan Oxland, Patrick Callon and Stephen Nevin ) come and try to build it at the 2008 Northumberland Dry Stone Wall Festival. Like the two pillars we are building today, this was very tricky to figure out, especially how much to 'twist' the two walls as they curved upwards. The ten flat long stone rungs held the ascending walls in place and stopped the 'rubble helix' from falling over.

Our two twisted pillars were coming along well, but every stone has to be placed and shaped and repositioned several times before feeling good about it actually looking 'right'. (As if a twisted pillar can ever actually look right?) But seriously, this has turned out to be more awkward than we first realized. Recently we have been doing a lot of weird pillars. Entrance gate columns with curving Japanese style contours at one job, another one that had water flowing out from the top of it, two others that were over 6 feet tall and 4 feet thick. I'm thinking of calling this chapter in my life Pillars of the Peverse.

As promised, here are two visualizations I drew yesterday in Sketchup of this new 'twisted' project, to try to figure out how it would look - and, based on what we saw, how we would go about building it.

Below is a picture of how far we have come today on one of the pillars.

It looks like who ever was building this pillar was drunk! We have ended up using rebar as batter guides, twisting them clockwise and held in place at the top with a square piece of plywood rotated 45 degrees to the base and held with duct tape (you cant see that in this picture) Bungee cord string-lines help us to line up our stones with the 'splayed' geometry of the twisted sides.

The secret handshake or the secret cold shoulder ?

While we might wonder what the secret Masonic handshake actually is, we understand that it was developed as a way masons could recognize and show 'respect' for each other, without necessarily speaking. ( The 'nonspeaking' part didn't imply that they didn't like each other ! ) The handshakes were a way for those who worked in stone to express their solidarity with other masons. As part of these perhaps antiquated rituals, secret handshakes allowed masons to express fraternity and above all 'friendship'.

 When a mason apprenticed with a skilled Freemason, that mason would teach him a secret handshake, reflective of the degree of learning the apprentice mason acquired. When the mason traveled for work and gave another foreman the secret handshake, that person would know that the apprentice had learned a certain degree of masonry skill (along with the appropriate handshake) from his instructor.

Presumably these masons saw it was important to acknowledge from whence and whom they acquired much of their knowledge. It was not right to pretend they arrived at their level of skill and method of construction without any other mason's help or learned what they did without being associated with any organization along the way. Unfortunately this may not be the case anymore. Competitiveness amongst masons is not necessarily a bad thing, however to refuse to give reference to those one has learned from or been helped by in ones acquiring of those skills, belies a basic fault which is likely to 'show up' in other ways later on, not only in their work but in their character too.

I tend to think that the stones in the wall will hold together to the degree that the person who builds it recognizes the responsibility he has in valuing and maintaining the freindships he has with those who have helped him along the way in his craft. 

To that end it is only right to make sure the contriving of contentious and rivalrous factions amidst the community of wallers here in Canada is discouraged amidst those of us who seek to continue cooperating with one another to build not only 'walls without mortar ' but also without hostility.

Hand Tricks - Turning 'Rocks' into 'Stones'

Unlike the few problem-types we come across occasionally, (examples of which I described earlier this week) rocks are simply a pleasure to work with. Masonry restoration expert, and good friend Bobby Watt explains that the difference between a rock and a stone is that "a rock is simply an unemployed stone". It is safe to say all kinds of rocks will end up being very useful in your wall if they get half a chance. When you try to build with them, it's as if they actually 'want' to be part of your dry stone wall. They often have at least one or two nice faces. They are usually 'kind' faces too, the kind that are agreeable in terms of working together well with others in a wall.

Almost any rock will 'work' naturally in the wall because of its elongated shape or flatness ( making them able to not only show the best face but also really 'get into' the wall). Many others 'work' because of their ability to take the hard breaks and still stay together or their willingness to take up the slack and add 'heart' to the middle of the wall.

Anyone who 'employs' rocks and makes good stone walls will know you can make walls out of any of the three basic types of rock - igneous, sedimentary or metamorphic. ( as well as almost any combination of these naturally occurring geological materials ) While I cant quite say that 'I have never meta-morphic rock I didn't like', I have found most rocks, like most people, to be level bedded, cooperative, responsive and dependable, individuals who bond well with each other and are beholden to the basic principles of form and function. They make good stones.

Special Handling Requirements

There's a kind of hard to place rock that thinks it is special and needs special recognition. It's a rock that often 'sticks out' from the wall, or appears to be set too far back into the wall. Usually this is because its difficult to know where the 'plane' of its 'special' face actually is, and so setting it becomes a problem. While it may seem that this type of rock would best be put in a prominent place in your wall due to its special shape or interesting colour, it is usually not a good idea. If a rock is chosen and placed merely for its looks, disregarding its structural value, then it will be a rock that is basically in a 'race to the bottom' While others in the wall cooperate and become one tidy entity, these 'posers' may end up bringing their part of the wall down, visually, if not literally.

These high-maintenance rocks, the kind you'd actually like to cement in the wall, can come in other shapes too. There are the ones that are not very natural at all. They are more than likely guillotined, or specially quarried/chosen 'veneer' stones. A wall that incorporates a lot of these so-called 'tracers', the kind that are way too shallow or with their bed face showing ( no matter how special or beautiful they are ) will start to slump and fall apart before too long.

Hard to Handle

Another type to be aware of is the 'hard-to-handle' rock. The kind that play and lay 'dirty'. They never seem to be happy where they are put. These are mean stones that not only pinch and crush and give you what Kevin Gardner refers to as a 'granite kiss', but have an agenda and want to bite your whole leg off. They are the temperamental ones which you would do best just to avoid. In thinking with my hands, is it ironic to describe these easily irritated stones as 'touchy'? Perhaps they are related to 'erratics'? Basically everything about them is edgy and angular. Their shape seems totally unadaptable. Their hardness only makes them more hard to handle.

While most useful walling material almost 'speaks' to you (if you are patient enough and take time to listen) these rocks don't seem to have anything to say. If you have to, place these rocks very carefully in your wall but remember you don't have to use every rock that you have in your stock pile.

Holding hands.

My hands held things all day today. They not only held rocks of all sizes and shapes to carry them to the wall we are building, but they also held chisels of all sizes and hammers of all sizes. Some hammers took two hands to hold. Everything I held required that my hands worked together. They never argued with each other or worked against each other. They augmented each other's capacity to split rocks and fit difficult stones together and basically get things done.

We talk about the way a thing 'holds'. A temporary wedge under a stone 'holds' until we find a better shaped one to fill the gap properly. A wooden handle 'holds' the head that is fitted tightly onto it. The batter-frame 'holds' the string-lines taunt while we sight down the wall. The whole wall holds together because we have built it well by maximizing the friction between each stone we have placed in the wall. We have made use of stone's three great properties, it's tremendous weight, it's great compressive strength and it's relative immutability.

Hands add another important capacity for holding dry stone walls together. Their flexibility. This flexibility is what is transfered to the structure of the wall when we don't use mortar. The wall becomes alive. It can move. It can yield to the forces of nature without breaking and falling apart. A wall holds, for all these reasons, and hopefully it holds for a long time. My grip gets tired after a while. My hands need to take breaks. But the wall goes on holding. A day of me constantly holding and letting go of things is translated into years and years of stones holding together. I am ok with this exchange of 'states 'of holding, like some metaphysical equation. I am pleased with my investment of energy, my holdings. Everything is held in place, because nothing is withheld.