Saturday, May 28, 2011

Third Foundation Pour

The work on the foundations is moving slowly and steadily forward. The site work is still moving along at a slower pace than I would like to see, and part of the challenge I'm dealing with in my new role is not being able to make decisions that affect the operations yet.

I'm still learning a lot about vertical construction in general, and construction in Ramallah with the local materials, labor and methods in specific. As such, I have only been able to give suggestions about ways by which we might be able to increase the speed of production or save some time on our delivery schedule only to be met with resistance from the contractor. It's tough to get him to consider changing "the way it's always been done" so I am forced to accept the speed of operations for the time being, while keeping track of ways it could be done differently for future reference and implementation.

Business operations aside, below are some photos from the third foundation pour which took place a few days ago.

(forms around remaining foundation footings)
(crew working on reinforced steel at the base of the future stairwell) 
(short concrete pump needed to park closer to the forms)
(concrete pour in action)
(foundation footings have all been poured)
As for the next step in the process, the crew is preparing forms for what should be the fourth and final foundation concrete pour (hopefully Monday or Tuesday of next week), which will include the stairwell and elevator shaft walls, the column necks and the wall along the north and west boundaries. As you can see below, the forms around the columns are being constructed using concrete blocks as it is a faster that timber forms for such small spaces. The down side, obviously, is that these concrete blocks will not be re-used after the pour and their cost is offsetting the time / cost savings of the shorter construction time.

(footings completed, and forms around column necks and internal walls being erected)
The crew takes their elevation level (using a water tube level) by comparing to the marks on the 'bracelet' that surrounds the building. This will allow them to establish the height of the next set of forms needed around the columns for the fourth foundation concrete pour.

(marking elevations using a water level)
After the next concrete pour and dismantling of the forms the day after, we will be ready to import / haul in the fill material that will go around the foundations and under the slab on grade, starting to really change the way the site looks and putting the tricky (and most time consuming) part of the 'adem (frame) construction behind us. 

And finally, I just had to take this picture in case anyone reading this blog is a Yankees fan. Apparently your ilk has made it to our construction site in Ramallah!

(Yankees paraphernalia)

Monday, May 23, 2011

Second Foundation Pour

The second foundation pour took place a couple of days ago, and everything went smoothly. We should have one more pour that includes the stair case and elevator shaft foundation, before starting to form the columns and prepare for the fill material to be placed below the slab on grade.

Below are a few photos of the rudimentary methods used in preparing and erecting the timber forms, which I continue to find strikingly old fashioned and ingenious at the same time:

(short footing edge formed with dirt and rocks)
(braces for the forms anchored with boulders)
The main element of support the crew needs during this stage is ensuring that the column and wall centers are accurate compared to the axis given to us by the surveyors, that the spacing and proper thickness of steel reinforcement bars are used, and that the layout of the steel for the column necks is correct. 

(close up view of one of the footing forms, still missing steel)
(forms completed)
(calculating steel reinforcement beam spacing and locations)
We calculated that we would need around 45 cubic meters of B300 concrete, placed the order and called the geotechnical engineer to schedule the testing crew again. They showed up a few minutes before the mixers arrived and took a sample from each mixer batch to test. After the 5 footings were poured, we ended up using 42 cubic meters of concrete.

(steel in place, concrete pump arrives with the fog from the valley)

(crews directing the pour, vibrating the concrete already placed, and smoothing the surface)
The next few days will bring the forming and steel setup for the stairwell and elevator shaft, the final foundation footing pour, the forming of the column necks, and preparation for construction of the 5.5 meter tall concrete retaining wall between the building and the street. 

Saturday, May 14, 2011

We Have Foundation Wall

Yesterday we poured the first batch of foundation-strength concrete (B300) into the forms for the building's Foundation Wall. The reinforcement steel was laid out, tied to the foundation steel, and the wooden forms were held in place by metal wire ties as well as 6 mm steel bars connecting both sides of the forms together to withstand the pressure of the concrete being pumped into the forms.

Last time I posted about being amazed by the manual labor aspect of development in this part of the world, so I thought I'd post a few more photos to illustrate my point. Here's a shot of the crew tying the column starter bars in the proper location using their tape measure and string to identify the location, metal wire to tie the bars in place, and nails, large boulders, and 6 mm metal bars to hold the wooden forms in place.

(the crew tying starter bars for columns in place)
(the starter bars held in place with metal wire ties and 10 mm 'bracelet' ring)
(the L-shaped footings of the starter bars, all tied individually to the foundation steel)
(the Foundation Wall footing, all hand-tied and placed inside the hand-made forms)
(pick axe, buckets and shovels used to clear the debris from areas where foundation will be poured)

After the Foundation Wall reinforcement steel is in place, the electricians weld a metal strip along the footing to provide an "earth" network that will ground the building and dissipate any electrical charge that might need dissipation (electric short, lightening ... etc).

(electricians welding metal "earthing" strip)

This is the site the day before the second concrete pour. Forms are in place on both sides, tied to each other and held securely in place, with steel reinforcement bars for the foundations in place and starter bars for all the columns inside the Foundation Wall established.

The morning of the pour, the general contractor is on site helping spray water on the areas that are about to receive concrete to increase moisture content and decrease the temperature a little ... then the 52-meter pump arrives and mixers start to pour cement into the pump and the pump delivers it to the foundation forms.

(contractor waters the forms prior to pour)
(concrete pump hose starting to spew cement mix)
(the crew get to work)
(workers direct the pump hose while others follow behind with concrete vibrator to eliminate gaps)

And here's a video of the process so you can see everyone in action:

The concrete had to be sampled by the geotechnical engineer in order to ensure conformance with the required strength and mix standards. The concrete blocks will be tested / crushed in two batches: once after 7 days and again after 28 days.

(concrete sample-collection blocks)
(first sample collected and labeled)

Finally, here's what the site looks like at the end of the following day. The crew cuts the 6 mm bars holding the forms together, removes all the wood frames, pulls all the nails out of the wood, then stacks it up according to size to get ready to build the forms for the next round of column foundations (the base of which can be seen beyond the Foundation Wall in the pictures below). 

(Foundation Wall poured, and forms taken apart)
(crew stacking the wood from the forms for future use)

I should note that these guys work from 7:30 am to 3:30 pm, every day except Friday. The more experienced (master) workers make 145 NIS (around $41) a day, while the less experienced (apprentice) workers make 85-90 NIS (around $24-$26) a day. 

Almost without exception, they love watching WWF wrestling on Thursday night television and talking about it the next week.

Thursday, May 5, 2011

Foundations & Concrete

Work has been progressing relatively quickly at the site for the past week. Once the marks for the foundation axis were established, the crew went to work setting up forms for the foundations that will support the building columns. I find myself constantly impressed at how old-school the methods used to accomplish this work are: all the measurements (after the surveyors gave us the initial markings) are taken with a tape measure and the crew uses string, a level and spray paint to mark form locations, all the elevation levels are taken with a clear hose filled with water, then measured from the benchmark set by the surveyors on the 'bracelet' fence surrounding the site, wood boards are fastened together using metal wire and supported by large rocks and dirt on the outside edges.

Keep in mind there have been only 4 workers on the site this whole time, we only added a fifth two days ago to prepare for the pouring of the first layer of concrete (the Blinding, called 'nadaaf' in Arabic, or clean layer) which will allow us to set up our steel reinforcements on a uniform, horizontal surface.

Below are a few photos of the site over the past few days, showing various stages of development:

(workers and foreman discussing progress)

(setting a new mark for the edge of a concrete form using string and a level)

('bracelet' on the right and forms on the left, before cleaning the pour area)

(the forms taking shape)

(areas around the forms are getting cleared of debris)
In addition to the construction oversight, project budget management and scheduling, I've enjoyed learning (or remembering) how to perform some of the engineering calculations required for the ordering of materials and supplies. We had our first order of reinforcing steel arrive at the site today:

(delivery truck unloading steel)

(steel of various thicknesses and shapes, based on the foundation design)
After finalizing our price negotiations with the concrete plant yesterday, the time came to receive the first batch of concrete for the nadaaf areas that were ready. Based on the surface area we calculated and a 10 cm thickness, we ordered 15 cubic meters of concrete with +/- 2 cubic meters that were allowable for return if need be. The mixer trucks carry 9 cubic meters each, so we had two mixer trucks and a big (52 meter) pump truck come out to the site today:

(setting up for initial concrete pump, & spraying water on the ground underneath it)

(ready to go)

(pumping begins and the crew goes to work guiding, shaping and smoothing)

(each crew member knew what to do, worked very efficiently)

(tough job of guiding the erratic pump hose manually)

(foreman giving directions on depth)

(almost done)

(foundation base is in place)
We can't forget the floor of the new site bathroom (not quite portable), so that there's a flat surface to stack the concrete bricks on for bathroom walls:

(barrel with sawed opening in the middle)
And here's the site after the week's work was completed:

(1 week down, 76 to go)
The crew started right back up setting forms for the remainder of the foundations that will get poured with the next concrete order. We used 16 cubic meters this time around, quite close to the estimate we calculated. Next week should be more of the same, but we'll get closer to pouring the actual foundations and ground beam, which will allow us to set up the column necks then fill around them to get to the finished slab elevation for the bottom of the second basement floor.