Saturday, December 17, 2011

And the project site gets busy and messy

Work on the project site began on November 28th. After three weeks of work we have a site that is filled with activity, lots of big holes, and a big pile of dirt. Working at the site is a team of 25 labourers working at squaring and leveling the foundation holes in preparation for putting down a solid base upon which the foundation pads will be built. Also being worked on is the cutting and bending of all the rebar required for the foundation concrete.

On the bottom of the picture you see the pile of dirt that stands about 2 - 15 feet tall. Most of this was dug and piled there by an excavator. The labourers use pick and shovel to trim the sides of the foundation holes until they are at the correct size and square. Then they level the bottom of the holes and bring them to the correct depth - with +/- 10mm.The holes are then connected by the labourers digging the trenches for the strap beams and tie beams that will bind all the foundation pads together. In the top left corner is a pile of rock dust and a pile of crushed rock used to line the bottom of the holes and provide a solid foundation base. No use working on a sandy foundation. Such a structure just would not stand up very well, especially in a very active earthquake zone.
On the top of the one dirt pile can be seen a slab of concrete that has been cut into 2" squares with tie wire imbedded in square. These will be used to hold the rebar in place until the concrete has been poured and set.
In the top right corner labourers are busy at cutting and bending the rebar to prescribed length and shape for the foundation pads and columns. There are hundred and hundreds of pieces to be bent before pouring concrete can begin. A bit of a closeup can be seen in the pictures below.

Our office is rapidly taking shape. Furniture has arrive, window frames have been installed, and glass has been installed in the window frames as of Dec 16th. That means the breeze will no longer blow through the office and it won't be quite so cold in there. The warmest place still will be the top of the dirt pile when the sun shines. That seems to be the place we sit to have most of our discussions regarding the project progress and technical issues.

 A difficult situation we encountered was mud in the holes. The holes have broken into the top of the water table resulting in water pouring into them. The bottom of most holes is in gravel with some clay mixed in. However, the water coming up is also carrying considerable amounts of silt with it filling the bottoms with a mud slurry, in some places as much as 18" deep. Not at all a good base for the foundation.

Maybe laying down some crushed rock and rock dust will help squeeze the mud to one end of the hole and then out.
Plan 'B' - maybe tamping the base will force the water to the top, seal the water table, dry up the holes and provide a solid foundation.
Well if all else fails go to plan 'C'. Nothing seemed to provide a really good solution. the first project site meeting was held on Friday, and plan 'C' is to place rock on the bottom that will settle on the solid gravel base. The space between the rock will be sealed with rock dust. This will bring the base above the water table preventing any further mud from coming to the surface while at the same time providing a solid base for the foundation.
We have access to the roof of our four story office building from which we have an absolutely wonderful view as can be seen in the following pictures. The first picture of this post showing the project site is also taken from this vantage point providing an excellent birds eye view of all the activity below.