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Wednesday, March 9, 2011

Rebuilding Christchurch

                   Creating the Heritage for our Grand Children*

*While this blog talks about Christchurch, some thought should be given to implementing such measures in all areas of New Zealand.  All are prone to earthquakes.

My family and I have been very lucky.  We live about 50km north of Christchurch and while any earthquake above about a 4.5 rattles our house, only a few ornaments have been knocked off the shelves and the house hasn't taken any damage.  It would probably be a different story if a 6.3, like the recent one under Christchurch happened here.  One of our sons was driving in Christchurch during the quake and just missed being flattened by a falling building.

Christchurch, despite the damage and loss of life, fared remarkably well.  Old brick buildings came down and a couple of modern ones as well.  The suspicion at this point is that the modern buildings  collapsed  because of the soil they were built on rather than any lack of compliance with the building regulations.  Our Prime Minister has ordered a full enquiry to get to the bottom of the situation and to see if the earthquake proofing regulations must be updated.  Rescue teams from around the world have said that this is the 'best' disaster they have been to in terms of the organization and support from the entire country.  Compliments to our leaders past and present.

Despite fairing "remarkably well" it looks as if around a thousand commercial buildings will have to be demolished and that doesn't include residential properties.

Now we have the task of rebuilding Christchurch.   This includes both commercial buildings and at an early estimate, 10,000 dwellings.  Some heritage buildings will undoubtedly be saved but overwhelmingly we will have to build anew.  So what do we want to see in Christchurch.    Below is a hodge podge of ideas in no particular order - brainstorming if you like.  I will keep adding to it and if you want to have your say, please make a comment.

The urgent aim at present is just to get the city up and running.  It seems very harsh to ask the planners to use this opportunity to create a better city.  However, if we don't do so, we will end up with a patch work and much greater expense if we decide to incorporate any of the following ideas later.  It will be far less expensive to incorporate them now while the infrastructure is upside down and a huge amount of energy is being put in to restoring Christchurch.

Solar Power*
Just think of the price reduction for quantity we could achieve if we decided to put solar panels on the rooves of every new building or better still, if the technology is up to it, to use solar panels as the roof (saving the cost of the conventional roof).  Here I'm not talking about a few panels per building but rather the north facing slope of every new roof completely clad in panels. Technology is well under way, also,  that turns windows into solar panels.  Every north facing window which receives the sun could incorporate this technology.  The reduction for quantity would extend to all the ancillary equipment such as inverters, grid compatibility electronics and so forth.  We should get our best people from Pharmac** on the case.

*In March 2011, Japan announced that it is thinking of requiring every new building in Japan to be clad in solar panels.  This follows the decline in generating power due to Fukushima.

**Pharmac is our medicine buying organization which results in the medicines we use in New Zealand costing us as little as a tenth of what other first world countries pay (much to the disgust of Big Pharm in America)

With the huge size of the investment involved, we could afford to send a couple of our best engineers on a world tour, starting with and ending with Germany, to thoroughly investigate the state of Solar technology at present.  At the same time, we could introduce smart grids to Canterbury.  It has to come sometime, and  better sooner than later.  The same engineers could examine the state of smart grids in the world.  There are many problems for power companies associated with the introduction of smart grids and with the incorporation of large sources of renewable energy.  The sooner we get a handle on how to manage smart grids and multiple inputs of energy from small generators, the better.   Christchurch could turn into a major net generator of electricity.  We would soon be running electric  cars which are entering the market this year, with stably priced electricity from our own rooves rather than with ever more expensive petrol and too-valuable-to-burn coal. Doing the introduction of solar on this scale would introduce a high level of standardization which would keep the price down for later introductions of solar.  It would  decrease the cost for anyone with a house that wanted to retrofit solar.

And how about a solar water heater for every new house.  An often heard estimate is that a third of the electricity used by a house is to heat its water.  Again, huge economies of scale could be achieved by using  a standardized water heater for every new house and we produce these in New ZealandTo the government I say don't you dare even think of buying these overseas.  We have our own solar water heater industry.

Roof gardens
On rooves not clad with solar panels, how about roof gardens.  Many cities are incorporating these now and they can be decorative, making a pleasant place to sit and sip coffee or can even be growing salad greens, tomatoes and herbs for downstairs restaurants.  The technology now exists to use very light rooting medium in combination with hydroponics. In some locations, one could even have walk ways between buildings, eliminating the necessity to even come down to ground level to go from, say a cinima to a restaurant

Wood Construction
One of our MP's, Jim Anderton  suggested rebuilding with wood.  In case you are thinking in terms of 4 X 2 house construction, this is not what is talked about.  Laminated wooden beams are incredibly strong and resilient and wooden buildings can be built many stories high.  Ply wood cladding, glued and fastened to structural members adds a huge amount of extra strength.  Wood is extremely flexible and has great vibration dampening properties.  Wood is a particularly easy medium to use to achieve whatever style is desired.   Wood construction can be made virtually fire proof, vermin proof and UV proof.  I don't think there is any question that wood construction should be very seriously considered and investigated.  However, there is a potential problem.

The hidden cost of contracting such work overseas is immense.  Instead of buying overseas, let us become the world center for building reconstruction for the earth quake damaged areas of the world using our considerable wood resources to sell know how and value added products.

There will  be a temptation to do a patch up job on some buildings, notably some of the damaged dwellings.  Come the next earth quake, they will be further weakened or destroyed.  Insurance companies would be foolish to insure such buildings.  The construction must be carried out to a standard such that any building passed will be re insured for the same premium that a similar building in a different location would attract.  This must be the criteria for the necessary standard of repair.

For private houses, one can build, for instance, on floating foundations*.  With a floating foundation, if another quake does come and the house tilts, it won't break. Houses built on floating foundations won't have liqufaction coming up through the floor.  A floating foundation must be strong enough that if it tilts, it can be releveled.    Above all, any rebuilt houses must be earthquake proof.

A floating foundation is a reinforced cement slab with reinforced beams underneath, all cast in one pour.

Overhead Power Lines
It is very nice having buried power lines but not very practical for an earth quake prone area.  Overhead lines are far less vulnerable to damage and are far more quickly and cheaply repaired than buried lines.  Some work might be done to reduce the visual impact of overhead power lines but putting them underground should not be considered.  If there was some practical way of having water and sewage above ground, that would also be desirable but unfortunately this is probably out of the question.  Keeping the power on after a disaster greatly alleviates the suffering of the effected population.  Having electricity can help alleviate the lack of piped water and sewage.   With power available, one has cooking, heating, water sterilization, and communication.  Power tools can be used to repair damage and water can be pumped if a source is available.

Car Charging Points
Electric cars are coming to the market this year (2011).  To attain the considerable benefits from electric cars, there must be convenient outlets to charge them.  In the rebuild of Christchurch, much road work will have to be done and streets will be dug up to repair sewage, water and electric lines.  This is a perfect opportunity to put in the necessary cables which will allow cars to be charged where there are parking meters today and in the parking lots of businesses.  They should be card swipe units which allow you to dial how much charge you want and at what priority.  In addition, lots should be set aside for the construction of battery changing stations a la Better Place.  Whatever the case, lets get the necessary power lines installed while the roads are being dug up anyway.

Sorting out Road Names
How about, while we are at it, sorting out the names of the roads in and around Christchurch.  Some roads change their names as many as 5 times as you drive along them.  Work out some system of deciding which of these names is to be used and change all the others to fit.  Christchurch is a confusing town to navigate in.  The CBD is nicely squared off but outside of there, the roads radiate out in every which way.  Knowing, for instance, that when you are on Pages road, Baldwin's road, or Aldwin that you are actually on Ensors would greatly aid navigation.

Thermal Mass in Houses
The insulation of a house is only one factor in making it comfortable to live in.  A great deal can also be achieved by increasing the thermal mass inside the house and putting the insulation outside rather than in the walls.  This evens out temperature variations and retains cold or heat that you have spent money in achieving.  If you are using free heat by allowing sun to shine into windows, this heat is retained overnight.  If you are cooling by allowing cool air in at night, this is retained through the day.

Heat Exchange Windows
It is highly desirable to have a high level of air exchange in a house.  This, however, wastes heat in cold days or wastes "cold" in  hot days.  You pay money to heat or air condition your house.  Windows exist which transfer heat between outgoing and incoming air.  They could be considerable improved by using counter-flow technology.  Such windows allow a good exchange of air while maintaining the temperature you are trying to achieve in your house. New Zealand could become the leader in this technology while improving the livability of New Zealand homes which are famous for dampness, mold and poor thermal characteristics.

Large Hats
A house avoids a lot of the problems of leaks simply by having a large overhang on the roof.  It is not the whole solution but is an important component.  Put in the building regulations the requirement for a minimum required overhang.  This might be larger for two floor houses than for one floor houses.  While we are at it, legislate for only long run roofing.  It is light, strong, easily replaced, only dents if something falls on it and "bridges" rather than collapsing if the whole house falls down.  It needs lighter underlying construction than ceramic or cement rooves and hence makes a more earthquake resistant dwelling.  Who in their right mind would want a great weight of fragile cement above them when an earthquake hits.  Better still, make the roof cladding out of solar panels.

It hardly needs stating that brick chimneys are out.  If you must have the style get one of the fibre glass ones with a steel flue inside.   If someone insists on a brick chimney, cancel his insurance.  The fire service wasted thousands of hours taking down brick chimneys when they should have been doing far more vital work.  While we are at it, brick chimneys should be eliminated from all of New Zealand.  No place on our islands is immune from earthquakes.  Cut the gorgons knot.

Friday, March 4, 2011

The Christchurch Earthquake

I'm writing this blog as if it is fact.  It isn't.  It is pure speculation.  Joining the dots if you like and perhaps I am seeing spots in front of my eyes.  Below is a tentative explanation of why the recent 6.3, highly destructive Christchurch earthquake occurred.

Many millions of years ago a volcano erupted on the continent of  Zelandia.  Many years later, despite the fact that the local people called it Te-ahu-patiki* a European explorer would name it  The Banks Peninsula.

*Actually, this is the name for one part of the Peninsula but it seems to be the nearest to a name that applies to the whole mountain.

The volcano erupted offshore and grew as more lava poured out of the earth. Erosion moved rock and soil down hill.  Eventually the eroded material joined the volcano to the nearby land aided by the material being washed seaward from the young rising mountain range to the west*.

*Because of the huge amount of material shed from the New Zealand Alps, the rivers, when they reach the plains are braided.  They fill up their stream beds and jump to a new path spreading new material back and forth across the plains like giant grouting machines.

The huge weight of this new mountain pushed down on the earth and the mountain sunk, trying to become isostatic with its surroundings.  Molten sills and dikes and the heat under the volcano helped with this process, making the material supporting the volcano a little less viscous than it otherwise would be.

In time, the volcano died, underground magma cooled and solidified and the volcano was locked into its surroundings.  All this time more material was washing off the volcano to be  deposited on land to the West and in the sea to the North, East and South.  The fast growing mountains to the West continued to wash material down around the volcano.  The volcano got lighter and lighter while the ground around it got heavier.

The volcano was no longer isostatic with its surroundings.  It wanted to rise but it was locked into the surrounding land.

On Sept 4, 2010 a nearby fault ruptured.  This fault had nothing to do with the volcano.  It is an east west fault coming off the north south plate-tectonic-fault that runs down the middle of the New Zealand Alps to the West.  Unfortunately, this fault points directly towards the north side of the Banks Peninsula right on the southern edge of Christchurch.  Following the Sept earthquake, after shocks just kept coming.  Between the Sept 4 quake and the Christchurch quake there were just under 5000 aftershocks.  Eventually the rock was sufficiently weakened that the volcano could pop up. The break in the rock was shallow so even thought the quake was only a 6.3, it caused huge vibration in the nearby area.  The Sept 4 quake was 40km from Christchurch, the 6.3, only 10km away.  Because it was a upward break on the volcano side and a downward break on the Christchurch side, it caused huge vertical accelerations.  It was akin to someone cracking a whip.  Unfortunately, parts of Christchurch are built on a swamp and the closer to the coast, the swampier it gets.  Further inland, the Alps have spread layer after layer of shingle (gravel) on top of the land, compressing and stabilizing it.

So far so good.  That's a theory but a Scientific theory is measured by how well it can make predictions so what would one predict if the above scenario is correct.

1.  The volcano: the Banks Peninsula, should have risen during this quake and will continue to rise as further after-shocks occur.  I must admit, I have cheated a little with this prediction.  Someone told me he had heard on a radio program that the Banks Peninsula had indeed risen.  That was what triggered off this blog.  So how about other predictions.

2.  The Banks Peninsula should have tilted.  While the North North West side should have risen, the South side should have hardly risen at all.  In fact as you go across the volcano from North West to South East, the amount of rise should be less and less.

3.  The rest of the volcano is still out of equilibrium with the surrounding rock.  One would expect more earth quakes which will center on the Western and southern rim of the volcano and possibly to the East.  Unfortunately, there is no way of predicting when, but a major earth quake might be preceded by some small ones on the other side of the peninsula from Christchurch as the rocks begin to rupture.  All the after shocks we are having,  continue to weaken the rock on the other rims of the volcano and the rock on the south rim will have been bent by the rise of the North Western side.

4.  Following any major quakes on the other rims of the Peninsula, that side would be expected to rise as well. The shore line of the Banks Peninsula should rise and the harbors become shallower.

5.  Communities to the West and South of Christchurch should expect some pretty large quakes, possibly in the near future and Christchurch will continue to experience shocks, some  fairly large, as the Banks Peninsula achieves equilibrium with its surroundings.  After-shocks should go on for a considerable time interspersed with some pretty large events on other sides of the peninsula.
It is likely that no quakes as devastating as the 6.3 will occur on the Christchurch side.

7.  The after shocks from this quake are unlikely to follow the same pattern as aftershocks from the Sept 4 event.  I have no idea whether they will be more or less but since the cause is different, the pattern should be different.  If they are greater and stronger, this would indicate that the volcano is actively trying to reach equilibrium and might increase the likelihood of large events radiating from other sides of the Banks Peninsula

Postscript.  Since writing this blog, I have come across a most interesting site from GNS Science.  Click here. 
Note that the north part of the banks peninsula moved up and to the west while the land to the North moved down and to the East.  If this blog is correct, sometime in the future one would expect to see other parts of the peninsula move upward and probably to the west with energy focused toward the land opposite the risen land.  This could be toward the ocean or toward Ashburton.