Thursday, June 14, 2012

East Side Roof Terrace Slab Completion

There has been considerable activity since my last post. Form work and rebar work on the east side roof terrace slab has been completed. The beam rebar has been dropped into place in the forms with progress now being made on the slab rebar. Other tasks being worked on at the same time is the back filling around the underground water tanks. This is now about 75% complete. The electricians have also arrived on site and will be there now until the building is complete. Their primary task is to lay the conduits that need to be in the roof slab, and they are running other conduits on the ground floor while they wait for the slab rebar work to be completed so they can do their work.
Rebar for the slab and roof soffit has been completed. The perimeter forms still need to be installed and the boundaries for the trowel finish floor area need to be defined.

 The perimeter form work is complete. On the west side we have completed the concreting of the first floor columns. Eight are wrapped with jute cloth to aid in keeping them wet for curing. The other six still have the forms around them as they were concreted earlier in the day that the picture was taken. These forms will be removed in two days and the columns will be covered in jute cloth.

Noticeable are the little grey blocks in the rebar. These are cover blocks that insure the required spacing between the form and rebar is maintained during the concreting. These cover blocks are made of concrete, and were made on site.
Also, the perimeter of the trowel finish floor has been defined by the forms in the middle.

This is the morning of the east side slab concreting day. We were to begin at 6:00am and this is about 7:00am. The concrete supplier was a little late in arriving to finish the installation of the pumper piping and thus we were delayed until around 8:00am before we could get started with the concreting.
The day went fairly well. These types of days will usually have some sort of challenges that will need to be worked through and this day had its challenges. All things considered, the day went along quite well. No injuries were sustained and the final product is a very well finished terrace floor.

The concrete was moved from the trucks to the slab by a concrete pumper again. It is a very loud machine but very effective.
The pumper was parked on a neighbouring property as that was the only location the pumper could fit and still have room for the concrete trucks to access the pumper.

This is the path of the pipes from the pumper to the concreting area. The distance from the pumper to the farthest point of the slab is over 100 meters with an additional six to seven meter rise. It all went smoothly and the pipes never got plugged.

All in a days work. The man sitting on the pipe is there to remove sections as they are no longer needed. Secondly he sits on the pipe to insure it does not fall off its perch as it pulsates back and forth. This is near the beginning of the concreting day.
The man in the blue hard hat is our general contractor’s senior working foreman. He usually does not let others run the power trowel, although I have run it at times when he was busy with other things.
The man in the white hard hat is the senior engineer for the architectural firm representing the client, SDSS. He was able to convince the foreman to let him run the power trowel for a bit while the foreman did some quick patching.
 The finished product on the first half of the pour this day. The finish is nice and smooth. The bottom edge here looks a bit rough but that will be a good bonding surface for the brick wall that will be built on the edge.
On the far end are some men putting down jute bags. It is around noon and the day is already very hot. It was over 20'C by 8:00am and at noon it was well over 30'C with little or no breeze. This made for very quick curing conditions so steps had to be taken to cool the concrete a little to prevent it from curing too quickly.
Later on a dam will be built around the entire outside edge which will be used to hold water creating a shallow pool to aid in slow curing of the concrete.
The concreting is completed and the power trowel work is also complete. It is about 5:30pm. A long day, but a successful one. Curing with water will continue for 14 days, and the forms will not be removed from the slab portion for 21 days. The forms for the beams will stay in place for 28 days.

One more large slab to concrete, which is scheduled for the 30th of June, and one small slab for the potable water tanks scheduled for the 13th of July.

Everything is moving along right on schedule at the present time.