News of Progress from Usalama

During a recent trip to Usalama, project leader Charles Newman was able to meet with the Primary school students, teachers and administrators.
The 4 new classrooms built in 2010, as well as the library built in 2009, are still being used daily and show few signs of wear. Structurally, there were no apparent cracks in the concrete, and the roof systems showed no signs of sagging or splitting.
During conversations with the school administrators, we reviewed the schools tests scores from the past 5 years. Since 2007, the students scores have risen by 15%. This can be due to various reasons. The new classrooms have enabled the administration decrease the class sizes - increasing the students exposure to the cirriculum and individual attention. The classrooms themselves also provide improved lighting and a ventilated environment conducive to learning and studying. The library has also had a positive effect. Not only do the students now have access to over 4000 books, but the school administration has initiated partnerships with neighboring libraries to start book lending programs.
In the past two months, the school has received 3 major awards: 1st in the district for most high test scores, 3rd in the district for highest average score, and 3rd for best school administration. We at EWB-NY cannot be happier for the community and their hard work and dedication to improving the lives of their young students.
We are continuing to work with the our donor, Mwikali’s Gift, and the community. Soon we hope to coordinate a close-out trip that will involve the monitoring of one final construction project of the community’s choosing.

Completion of 4 New Classrooms in Usalama

    Our implementation project for June - August 2010 was recently completed on schedule and under budget.  Project leader and architect, Charles Newman traveled to Usalama for the entire length of construction.  Mathew Sisul, an engineer and long time friend of the community, and Avi Guter, a structural engineer, also each spent 6 weeks on site helping to guide the construction effort.
    Our goal was to construct 4 classrooms for the community of Usalama.  Not only would such an effort culminate in 4 new, structurally resilient spaces that would allow for smaller class sizes for the students, but the construction effort itself would serve as a forum during which construction details and methods could be exchanged between our team and the community.  Below is a general recount of our construction efforts, conducted along side the skilled masons of Usalama.  (More detailed accounts, concerning specific details and the day to day events lives of the volunteers can be found in the preceding blog posts below.)

    The previous implementation trip in 2009, a library project for the community, taught us many lessons that allowed us to streamline our construction efforts during this trip.  The library, a reinforced masonry structure, exhibited the typical construction practices of the region.  We worked within these practices to ensure feasibility and clear communication with the local labor. Having this previous experience allowed us to improve upon our design strategies.  We modified not only many design details, but also methods of operation and scheduling.  Further, we worked with much of the same skilled labor, which opened up communication avenues from the beginning.  Each of these enabled the project - of a much larger scale than the library of the previous summer - to come in further under budget, to remain on schedule, and to be completed as an improved example of quality design and construction.
    Our first major design improvement concerned the foundation depth.  During our library project, our footing reached a depth of about 32”.  After receiving input from many architects and engineers here in New York, we opted to decrease the depth of the footing, which saved on material and labor from the get go.

This modification also included reinforcement that extended up from the footing and up through the buttresses.  This reinforcement continued up the length of the wall, eventually connecting and embedding into the ring beam.  This continuous reinforcement is a perhaps the primary structural improvement over the library project.  We also opted to use brick in every other bay of the exterior walls.  These brick bays each included a window, and were located between the stone buttresses to minimize any structural weaknesses that might occur as a result of the weaker material.  This introduction of brick provided substantial costs savings in our primary building materials.  Upon plastering of the interior, we inserted a control joint at the brick/stone junction to minimize any cracking that might occur.  We opted to use brick much more often after learning of such responsible practices.
After completing the ring beams, we constructed the gables above our of brick as well.  By embedding the ring beam with 12”x12” pieces of wire mesh, we were able to connect and reinforce these portions of the walls with larger, continuous pieces of wire mesh.  This tied the entire structure together, creating brick walls that is every bit as strong as their adjacent stone walls.
    The exterior spaces presented various challenges.  By this time, we had refined our planning strategies to work within the labor capacities of a single day of labor.  It is important to mention that pouring such quantities of concrete could not have been accomplished without the volunteer labor of many of the parents in Usalama.  On such days, we had the help of 10 - 15 volunteers.  Such involvement allowed us to retrieve water throughout the day, mix the concrete, as well as to instill an ownership of the project in the community at large.  Moreover, such help allowed us to retain the skilled labor at important locations in the production line.  Each of the two exterior slabs were approximately the same volume of a single classroom slab, though both sites required the formation of stairs.  Each stair required additional formwork, which in turn required accurate surveying, wire mesh considerations, and a clear, methodical approach.
Our masons took on numerous responsibilities, often taking the lead in helping ensure a smooth day of concrete pouring.  One detail of note, is that of improved column bases.  During the construction of the library, we were confronted with the reality that wood columns would eventually deteriorate due to ever present termites.  Our solution created a localized budget overrun after the purchase of 10ft steel columns.  This miscalculation gave way to a new detail for the classrooms that involved numerous short steel column bases.  These 18” bases elevated the coming wood columns 6” above the finished grade of the slab.  This, paired with a dose of pesticide around each, will ensure the protection of the columns for years to come.



    The final three weeks of construction became a logistical challenge.  As our team of Engineers Without Borders fell to one, the problems involving procurement of materials and construction oversight required careful delegation of responsibilities to the local masons.  By promoting our head mason, Matungi, to a more administrative position; issues of personnel, early morning tasks, and salary distribution ensured continuous productivity through to substantial completion. This relationship created a forum during which we reached daily agreements regarding piecework, orders of operations, and exchanging opinions of material quantities needed. 

    The community of Usalama has taken a large step forward in working to provide 4 new classrooms for their next generations of children and grandchildren.  The additional classrooms and social space will undoubtedly improve the learning atmosphere for the children, and the school at large.  Further, the lessons exchanged between our team of Engineers Without Borders and the local labor, will have lasting impressions that will run along side the advantages of the newly built structures.  Each of the masons maintained constant enthusiasm throughout construction, and will undoubtedly bring the knowledge of responsible building practices into their next local construction project.  It is much the same with our team here in New York.  Our lessons learned will be passed on to those working with us, and will be applied into our next projects for years to come.

Super Structure!

The following is a post implementation report by Avi Guter, the third member of the EWB-NY Usalama, Kenya field team:

When I arrived at Usalama Primary School on Tuesday, June 29th, 2010 the four classrooms had just begun to rise from the ground.  The stone walls were between one and two courses high, sitting on top of the concrete strip footings below.  This year, as Matt stated in an earlier blog post, we provided for vertical reinforcement in the buttresses.  Short dowels sticking out of the strip footing were lapped with bars that extended to the top of the buttresses.  We placed two twisted Y10 bars per buttress.  After every two courses of stone that were placed, we filled in the buttresses with concrete to engage the rebar.  The vertical reinforcement was sized to resist the overturning moment due to wind.

For horizontal reinforcement, we placed barbed wire every other course and wrapped it around the vertical buttress reinforcement at the ends of each wall.  The barbs allow the mortar to mechanically bond to the wire. The combination of horizontal and vertical reinforcement served to tie the wall together, distribute load, and make the structure more durable.  This is a departure from the thin flat metal bands of Misomo that were use on the library last year for horizontal reinforcement.

Between wall segments we left space for large windows.  In order to reduce costs we filled in the area below the windows with locally made brick, which is cheaper than the quarried stone.  The contrast of the deep red clay bricks was a nice accent to the grayish, light green and pinkish hues of the sedimentary rock that composed the walls.  Additionally, at the bottom of the walls we installed plastic pipes to intake air for natural ventilation.  The pipes were tipped slightly outward to prevent water from entering the classroom.  Metal screening was added to each pipe assembly to help stop mosquitoes from entering.

As the Fundis, or skilled workers, erected the walls it allowed Charles, Matt, and myself time to prepare rebar for the ring beams on top of the walls (and take a quick safari in Tsavo West national park!).  We kept the ring beams the same size as on the library - 6"w x 8"h - and used the same longitudinal reinforcement - (2) twisted Y8 top & bottom.  However, we used a reduced stirrup spacing of - R6 @ 12" O.C. - where the beam was supported continuously on the walls. This was to provide additional confinement for the concrete. In the locations where the beam spanned over the windows to serve as a lintel, we placed the stirrups at 6" O.C. to increase the shear capacity.

We also bent rebar to provide a connection between the top of the buttress and ring beam.  Simple angles were sufficient enough to lap with the vertical buttress steel and also develop horizontally into the concrete beam.  The ring beam serves to tie the top of the wall in place as well as transmit load between the walls.  One problem we noticed was that some of the stones in top course of the buttress were loose.  Because it is the top course there are no stones above to “lock” them in.  Since wood formwork is expensive and difficult to fabricate we decided against incorporating the entire top course of the buttress as part of the ring beam.  However, this would alleviate the problem of loose stones.

On July 7th we poured the first ring beam for Simba High.  In addition to the beam reinforcement we also embedded 12" wide pieces of chicken wire into the concrete spaced at 2'-0" O.C. The pieces stuck out the top of the beam approximately 12".  These small pieces of chicken wire were later lapped with larger pieces that spanned from the top of the ring beam to wood truss members above.  The chicken wire was to provide a backing for brick that was later to be installed above the ring beam in three locations: along the front of the classrooms and on both ends to fill in below the eves of the trusses.  Although the brick is mainly a façade element and is non-structural, we wanted to prevent it from becoming a falling hazard either from high winds or deterioration by securing it with chicken wire and mortar.

The ring beam also provided a connection for the roof trusses.  At every buttress we set 18” long 2x4’s on top of the ring beam.  The 2x4’s had nails sticking out the bottom that were embedded into the concrete.  Barbed wire or metal bands were also used to tie down the embedded 2x4’s.  The wire or metal band was wrapped around the bottom of the ring beam to hold it in place.  It was later tied around the top of the embedded 2x4’s.  Roof uplift due to wind is an important design consideration; therefore we wanted to ensure the roof would be adequately tied down.

The other three ring beams were poured on the following days – Simba Low July 10th, Tembo South July 12th, Tembo North July 13th.  Almost everything went smoothly, except one instance while pouring Tembo South.  One of the Fundis, Joseph, fell from his perch on top of the wall as he dumped buckets of concrete into the beam.  He dropped quickly and was caught by his shirt that got hooked on the top of the buttress.  Amazingly, he was OK except for a few scratches on his chest.

Coinciding with the successful completion of the ring beams on July 13th it was also Matt’s last day at Usalama.  We gathered all the Fundis and headed to Valentines, a local bar/guest house, where we celebrated with nyama choma (roasted goat), chapatti (flatbread), and plenty of Krest (bitter lemon drink) to wash it down.

Even with one man down, the next day we stayed on task and banged out all eight roof trusses for both classrooms at Tembo.  To facilitate construction, we staked out a full scale template in the dirt.  As the trusses were assembled two of the Fundi’s, Ben and James, took on the task of painting them all with a mixture of wood preservative and diesel fuel to protect against termites, a common nuisance in tropical climates.

The following day was equally as productive - we knocked out all eight trusses for Simba.  At the end of the day we got a special treat from John and Kennedy, two workers, who broke out a guitar and started to sing some of their favorite Kamba tunes “One Man, One Guitar.” It definitely brightened the mood after a long day of hammering, sawing, and nailing.

Our next task was to build up the brick eve walls above the ring beam at each end of the classrooms.  One difficulty this year was that the end walls were not perfect triangles, which made it harder to lay them out.  The Fundis used string and some 2x4’s to create, as best they could, the shape of the eve wall.  In addition to the horizontal barbed wire placed every other course, we used thin binding wire that bent around the barbed wire and stuck out beyond the face of the brick.  The binding wire was to twist around the chicken wire (described above) and hold it in place.  Each set of classrooms took one day to complete.  [Note: At Tembo, plastic pipes were inserted in the eve walls to provide exhaust for natural ventilation.]

On Monday morning July 19^th, Charles and I headed to Kalimani’s Metal shop in Kibwezi owned by Kennedy – the man we purchased our windows and doors from.  We requested Kennedy’s assistance to make a pot stand for a new stove that will go in the renovated kitchen.  Kennedy agreed to help and insisted that we stay as they tack welded together the support assembly.  The pot stand went through several iterations over many days before we felt it was ready.

Back at Usalama Primary School, the Fundis were busy erecting trusses.  They carried each of the trusses into the classrooms and propped them temporarily on their sides spanning from ring beam to ring beam.  When I arrived at the site I noticed the trusses lying on their sides and immediately had shores placed under the trusses to prevent them from bending out of plane.  Some damage had been done and was noticeable when the trusses were placed vertically - some permanent warping occurred and a couple of splice connections needed to be reinforced.  By the end of the day all 16 trusses were erected and temporary bracing was nailed in place to keep the trusses upright.

The next three days were spent excavating soil and placing hardcore for the exterior porch slabs situated between and in front of the classrooms at Tembo and Simba.  Parents came to help in designated groups that the Chairman, Mr. Jackson, arranged.  On Friday, July 23rd we were finally ready to pour the slab at Tembo.  Concrete was mixed on the classroom floor adjacent to where the slab was being poured.  We first laid down 4’x8’ pieces of light gage welded wire fabric (WWF) over the hardcore to reinforce the slab against cracking.  As we poured concrete we tugged up on the WWF to keep it in the middle of the slab.  It took us late into the day to finish, mainly because we miscalculated how much concrete was required and needed to prepare an additional batch, which cost us time.

The porch slab between the two classrooms at Simba, which is almost twice the size of the slab at Tembo, was ready to pour on July 26th.  The sloping grade in front of the classrooms required the porch slab to step down four times.  We used a surveying transit level to excavate the different bottom of slab elevations.  With help from parents in the morning, the concrete pour went smoothly.  After a delicious late lunch of stewed hen and cow peas bought for us by the Head Teacher Mr. George Katolo and Deputy Head Teacher Mr. Charles Wambua, we were energized and able to finish before sundown. 

As the two porch slabs were prepped and poured two Fundis and their assistants installed windows and doors for all four classrooms.  Like last year, all of the steel work was done by Kennedy at Kalimanis Metal Shop.  However, this year there were a total of 16 windows and four doors, many more than last year.  The inserts that held the windows in place were at slightly different elevations for the various classrooms.  This required some of the doors and windows to be sent back to Kalimanis for adjustments to the steel embed heights.  Additionally, because of the brick border that surrounds the windows we needed to make the steel embeds for the windows 12” long in order to be supported by the stone.  We did not want the windows supported only by the brittle brick, which was not even integrally connected to the rest of the wall with a running bond. 

After all the concrete, stone, and brick work was near completion our attention turned to the wood framing for the roof and porch.  The week of June 27^th – August 3^rd was spent finishing the installation of the perlins across the tops of the trusses, erecting porch columns, adding cross bracing between trusses, making small trusses to support the roof between the classrooms, and making two beams to support these trusses.  

When installing the perlins in some locations the Fundis cut notches out of the top chords of the trusses to make the perlins level.  These notches however compromised the integrity and robustness of the trusses.  Some notches even occurred at joints on the trusses.  We assessed all the locations and noted where repairs needed to be completed.  We suggested that on future projects instead of cutting into the trusses, the perlins should be shimmed up to make everything level. 

One major change this year was the addition of cross bracing between the roof trusses.  The braces serve to prevent all the trusses from ‘racking’ or tipping over.  Without the braces, the trusses have no lateral stability in their out of plane direction.  We also installed braces at the tops of the porch columns between the classrooms.  In this area there are no walls to block the wind and the roof could potentially act like a big sail.  The braces serve as the lateral system in this area. 

The last big task was to install the corrugated metal roof panels.  The highest quality brand sold in Kibwezi is Dumza, which are galvanized and therefore do not rust.  They are also extremely reflective so when the Fundis installed them they wore sunglasses.  Along the portion of the roof between the two classrooms we used twice as many nails to hold the Dumzas down because these areas are unprotected from wind.  Roof installation for Simba coincided with an end of semester graduation ceremony on Monday August 2^nd.  All of the parents who attended the ceremony were able to see all their hard work finally come together.

On August 4^th Kenya voted on their new constitution.  The Election Commission set up a polling station in Usalama at the library that EWB helped construct last summer (2009).  Charles and I biked to the school on Election Day and watched as Kenyans cast their vote.  It was a tremendous feeling to see the Library become part of such a momentous occasion.

Usalama Water Pipeline Update

The Usalama Water Pipeline is a gravity flow water system that connects to the main Kibwezi line and is meant to provide potable water for the village of Usalama. Mwikali's Gift contracted AMREF to design and build the project in late 2006/early 2007. As of today the project is incomplete with some water kiosks operational and intermittent water reaching the main tank.

One of EWB-NY's secondary goals during the Classroom Construction project was to perform a third party ex-poste evaluation of the Pipeline system in order to provide recommendations for remediation if necessary. There were some obvious limitations to our ability to perform a thorough evaluation. First, the project is incomplete, which makes "ex-poste" a little unrealistic. Second, we could not dedicate more than one Engineer (Matt Sisul) to the task, though he was teamed with the pipeline supervisor, James. This limited the extent in which the various system components could be evaluated and tested.

A little about the system:
The pipeline is run by the Usalama Water Board (UWB), a committee set up with the help of Mwikali's Gift and AMREF. The UWB is in charge of operation and maintenance of the system from the intake at the Kibwezi Pipeline junction, the mainline to the tank, the tank, and return lines from the tank going in two directions, north to Kiosks 1 & 2, and south to Kiosks 3, 4, & 5. The board also employs attendants to sell the water at the kiosks for 2 ksh per 20L Jerry Can. (Pretty Standard). The UWB pays the government water agency a tax for the use of the water that costs somewhere around 15 ksh per cu. meter. So the UWB makes a profit of 100 - 15 ksh per cu. meter water sold that goes toward paying attendants, maintenance and loses, the remainder of the money goes into a bank account for future capital expenditures.

Source:
The source of the water is the Umani Springs. Umani (or sometimes Umanyi) supplies water to Kibwezi town and many points north and south of Kibwezi (Makindu, Mtito Andei). The water emerges from the spring in a very clean condition, but likely picks up some bacteria in the pools before entering the pipeline. In 2006 the water at the spring tested positive for fecal coliform presence/absence.

Present State of the System:
It was not easy getting a sense of the present state of the system. But after discussions with many individuals and a first hand inspection I was able to get an idea of how the system is currently functioning in its incomplete state. The final system is meant to have a mainline that connects to the tank with two return lines, one going north to kiosk 1/2 and another south to kiosks 3/4/5. However, kiosk 1 is attached to the mainline and the return line is about 20 feet short. Kiosk 2 is attached to both the mainline and the return line, with a bypass system in place so the kiosk operator can switch between the two lines. Kiosks 3/4/5 are all attached to their return line. The tank does not receive adequate flow to fill in the 24 hour cycle, in part because kiosks 1/2 reduce the flow while operational and in part due to an overly optimistic design by the engineers at AMREF. Kiosks 3 & 4 can get adequate water when the tank is full, but this is rarely available due to issues with the flow into the tank. Kiosk 5 may be in a position to receive little to no flow, as it is in line with kiosks 3 & 4, and at a higher elevation, so perhaps when the tank is full and kiosks 3 & 4 are closed there may be potential, but that has not been verified.

Next Steps:
Our next task is to take the data collected during the pipeline inspection: alignment, elevations, pipe diameters/types, locations of intake, airvalves, kiosks, tanks, etc and try to create an "As-Built" profile of the pipeline. The profile can be used to determine the dynamic head losses in the pipe as the water travels from the intake to the tank and from the tank into the kiosks in order to determine:
1) That the profile and components are consistent with allowing water to flow via gravity.
2) What steps or changes to the system can be made increase the flow of water into the tank, thus ensuring adequate flow of water from the tank into the kiosks.
3) Key data is lacking in order to accurately determine expected flow rates, and that is the flow and pressure at the intake. We will have to set up a measuring program to measure the pressure at the airvalves closest to the intake and tank, as well as the flow into the tank (where pressure=0) at various times of the day, days of the week and months of the year to determine variation in flow at the intake and reliability of the system.

Pictures from the inspection are available here. See this older post for detailed maps of the system.