Phase 3
The construction Phase of the project has just started. It was first scheduled to start late January 2005, but the big problem at the moment is the building industry is just too busy. As there is so much work on it is hard to get a contractor to turn up on time. The main hold up has waiting for the concrete spray people. The main contractor did not want to dig the hole too early and have it there for weeks / months before the spray concrete would turn up and do the job.
The excavation would have to start no more than one week before the spray concrete people would be ready to start the job. Other problem would be if the excavation process had problems with it caving in. As we found a layer of sand only 600mm deep at the bottom of the hole was a real big issue. As the sand would not stop moving, and could cause the sides of the hole to cave in.
Breaking the OLD Concrete the easy way
Using an excavator to break up the concrete, this is the only way to break concrete.
Digging the easy way
The cellar excavation took two days, about 220 tons of dirt, sand and old concrete came out of the hole and from where the old shed floor was. To do this by hand would have taken a very long time, but the machinery made it look just easy.
It is all to easy for some of the soil to collape, the problem was a layer of sand about 600mm think at the bottom of the hole. As the sand is very dry, it just moves, and nothing will stop it. So this problem will have to be fixed before the steel work can be installed. Last year a neighbour around the corner had the same issue. He had to get the concrete spray people out twice, once to shure up the sand problem, and then to spray the cellar walls. This process just added another $6000 to the price.
It was decided to use scrap corrugated iron and timber from the old shed to shure up the cellar hole and stop the sand from moving. As if the sand can be stabilised, it will not be a problem. The photo below is of the cellar after shuring up has been completed.
Ready for the Steel Fixers
The steel fixers, this is the process where by all the plastic and steel reinforcing rods and mesh is placed the correct distance apart and in the correct place. As I had never seen steel fixing done before, I was not sure at first what they were doing. But it soon became apparent that they also did not know what they were doing :( As I was paying lots of money for this job, I was not very happy with the way things were going. In hind site, I would have handled things differently, but as the baby was not far away, I was not interested in problems, only solutions.
Some of the problems that had to be fixed before the concrete spray people turn up.
The steel work fixed up ready for concrete spraying
Ready for Concrete Spraying
The Concrete Spraying was in all a single day job, and the people doing the job did not stop all day. I must day they did a great job of the concreting. So bit they could have cleaned up a bit better. As they left a few rod hammed through the plastic, with some concrete around them. Easy to get out when it was still wet, but I did not notice them for a few days. This meant that I had to break out some of the 32MPA concrete and then pull the rods out of the ground. A hour or two later well I get them out.
Here are some pictures of the concrete spraying in progress.
Now it was just a matter of letting the cellar cure, and wait for the people to turn up and start the next stage. But was it, well a bit of a look at the steel work around the cellar, and well, you just could not get the hold down bolts in the right place with doing some fixing up. So the fixing up we did. Three days it took of re-tieing all the steel around the cellar, so that the hold down bolts could be in the right place. In all after the steel work was fixed up. The error was less than 10mm for all the hold down bolts except two, they were two out of the first 3 that were set into the cellar wall. This was not a problem as they were only out in one direction, and a simple moving of the plate on the bottom of the column was all that was needed.
The photos below give you an idea of the nice straight lines we got he reo to, well putting the mesh down, you would think the steel fixer could do that right. Well you would be wrong. In short I had to give close supervision, and at times cut the rod ties off that he had put on and tell him he had tied the wrong steel to the wrong part. Get him to do it again. The build ordered 7 sheets of mesh for the job. With some thinking and good us of the measure tape, I was able to put double mesh over the top of the cellar, only have a small amount of scrap. It took about two sheets to have double mesh over the cellar, but if I just let the steel fixer do it the way he normally does, I would have had two sheets worth of scrap sitting in the scrap metal pile. With only one layer of mesh over the cellar.
