PROGRESS REPORT ON THE BUILDING PROJECT FOR NKO
NKO Foundation is currently building a Medical-Surgical Center in Anambra state, Nigeria. The three-story center will have four levels. The first level will have all the diagnostic equipment, radiological equipment, Pharmacy, Ophthalmology, Ear, Nose and Throat (ENT), Kidney Transplant and Dialysis Center, Orthopedics, Urology, General Surgery, Neurosurgery, Primary Care, OB/GYN, and offices. The second level will have 10-large modern operating suites and two levels of overnight stay for post-op patients. Level three will be mid-level staff temporary stay that could accommodate at least 100 workers. Level four will be residential suites that could accommodate about 100 physicians. Construction at the site started in 2019. The pictures and videos of the construction can be found under “Projects and Services” “Our Gallery.” Below is a breakdown of the work done thus far:
DEVELOPMENT: SURGICAL MEDICAL CENTRE
LOCATION: ISIUZO VILLAGE, ODIDA OGIDI
SCOPE OF REPORT: SETTING OUT TO D.P.C. LEVEL
This report is prepared based on the following sequence of operation:
- Setting out
- First concrete blinding
- Preparation of columns/bases reinforcement
- Preparation of ground beam reinforcement.
- Erection of columns/bases with concrete
- Placement of ground beams reinforcement
- Casting of the foundation strip
- Striking of the ground beams formworks
- Casting of the reinforced concrete ground beams
- Laying of blocks on aforementioned beams
- Placement of reinforcement on the walls (rings beams)
- Striking of ring beams
- Casting of the rings beams.
- Filling of foundation with Laterite at D.P.C. Level.
DECEMBER 2019 WK. 3
1. SETTING OUT:
The building measures 78.09 meters long by 27.49 meters wide, or 260feet by 95 feet. The setting out started on 17th December, 2019, being the third week of that month. We were able to establish the four building points on the first day of the setting out.
On the second day of the setting out, we struck the profiles, and started marking the width of foundation, column bases and walls on the profile. Marking on the profile ended on the third day of setting out.
DECEMBER, 2019 WK. 4
2. EXCAVATION OF FOUNDATION:
Excavation of the building started in the fourth week of December, as soon as the setting out ended. Details of Excavation:
- Depth of the foundation was 1.2m or 4 feet
- Depth of column bases was 0.3m or 1 foot deep after the foundation trench excavation
Width of the foundation was 0.674m or 2 feet, 3 inches making the depth of the foundation at column base point to be 1.5m or 5 feet deep. Due to the topography of the land, we introduced upto three steps in a particular line, towards the width of the building. The first thing that was done as the excavation started was to establish the peripheral wall of the building, before partitioning.
JANUARY, 2020 WK 1
- The Excavation was not completed at a stretch, but in segment. It started from December, 2019 and lasted to the end of January, 2020. As the excavation was in progress, we were also marking the column positions and digging them as well with the three expansion joints whose width was double, the width of the foundation trenches.
- 3. FIRST CONCRETE BLINDING:
We started pouring or casting, the first concrete of 3 inches thickness in February, known as concrete blinding. The essence of this blinding was to cover the width of the foundation with concrete in order not to allow iron reinforcement to come into contact with the soil, which causes rusting.
- 4. PREPARATION OF COLUMNS/BASE REINFORCEMENT:
As blinding was in progress, the fitters or iron benders were busy preparing the starter columns and their bases. The columns were prepared with 20mm high yield tensile rods, with 8mm stirrups. The height of the columns was 2.7.meters or 9 feet. We have two sizes of columns, 85 of them have 6 bars, and measure 450mm by 225mm or 18 inches by 9 inches columns. These columns are mainly located at the periphery of the building and the major areas of the building. Other columns were 55 in number, and have 4 bars. These were placed in pairs at the expansion joints, partitioning and the open court areas. The column bases were prepared with 16mm high yield tensile rods. They measure 1.2m x 1.2m or 4 feet by 4 feet wide. The double columns, that is those with 6 bars, had bigger width, which is 1.5m by 1.5m or 5 feet by 5 feet.
- 5. PREPARATION OF GROUND BEAM REINFORCEMENT:
The ground beams reinforcement were prepared with 12mm high tensile rods. The beams were inform of inverted Tee shape, where the base is measuring 0.6m or 2 feet, and the and the upper one is measuring 0.75m or 2 feet, 6 inches high. The inverted Tee reinforcement rings were spaced at 0.45m interval or 18 inches and tied horizontally with 12mm bars.
- 6. ERECTION OF COLUMNS/BASES MARCH, 2020:
The erection of the columns commenced around mid march, and were cast with their bases with concrete mix of 1:2:4 ratio, that is one head pan of cement to two head pans of sand, and to four head pans of stones (Chippings).
Let it be noted that no aspect of this construction was done at a stretch. Each was done in pari-pasu with others.
- 7. PLACEMENT OF GROUND BEAM REINFORCEMENT:
It should be recalled that the form of the ground beam reinforcement has earlier been stated to be in inverted Tee form of 0.6m wide (2 feet) and 0.75m high, (2 feet, 6 inches)
The reinforcement is placed in 0.45m spacing from each other, and tied together with the columns the essence of the ground beam ie to ensure that the building is resting on sound footing, that is capable of withstanding any pressure or force on it. They are normally used in water logged area, or any soil whose bearing capacity is low (loose soil)
- 8. CASTING OF THE FOUNDATION STRIP: APRIL, 2020
Casting of concrete on the strip started in April, 2020. Same Mix of 1:2:4 was used for the lower part of the reinforced beams. The thickness of the reinforced concrete strips was 225mm or 9 inches. This is to give enough concrete cover to the reinforcement, which is 7 inches or 175mm thick. The casting was also done in segment, as the whole area was not ready at the same time for casting
- 9. STRIKING OF THE GROUND BEAM/ FORMWORK (APRIL, 2020)
The ground beam is a composition of the reinforced strip and the standing beam. Having cast the reinforced strip, the beams were covered with wood formwork to form a reinforced concrete wall on the reinforced concrete strip (floor). The thickness of the wall is 225mm or 9” inches.
- 10. CASTING OF THE REINFORCED CONCRETE BEAM
In casting the first blinding and the strips, three quarter inches (¾”) gravel was used but smaller one, that is half inch chippings were used for the beams, in order to avoid any honey comb after removing the formworks. The concrete mix for the ground beams was 1:2:4.
These ground beams were introduced in all the areas of the foundation trenches. All these reinforcement and casting were supervised by consultant structural engineer.
- 11. LAYING OF BLOCKS (MAY, 2020)
Laying of blocks took the whole of May, 2020. Blocks used throughout the foundation, were properly mixed moulded and watered. Block work really lasted for almost two months, because of the gradient of the project site. Nine inches blocks (9”) were used, because of its load bearing capacity.
The front elevation of the building, took four courses of blocks to be reasonably above the damp proof course level (D.P.C.). The mid point of the building took six to seven courses to be at the same level with the front elevation. The rear elevation took nine courses of blocks from the top of the ground beam which was two feet, six inches high from the excavation.
- 12. PLACEMENT OF REINFORCEMENT ON THE WALLS
While the block work was on going, the fitters started the chaining of the walls with ring beams. The beams were prepared with 12mm rods all through the whole walls, as they were laid. Chaining of the walls with reinforced concrete beams became necessary in order to ensure the stability of the foundation when load is imposed on it.
- 13. STRIKING OF RING BEAMS FORMWORKS (JUNE, 2020)
Striking of the ring beam from works started in the month of June, 2020 with the reinforcement and casting. As the iron benders were preparing the ring beams reinforcement, the carpenters started covering those that have been placed on the walls with planks. The thickness or height of the beams was 225mm or 9” (inches). The carpenters were using binding wire to draw the planks together very tight in order to avoid bursting of concrete after casting, and for the planks to lap properly.
- 14. CASTING OF THE RING BEAMS:
The ring beams were cast with concrete mix of 1:2:4, using smaller aggregate to ensure smooth surface after casting. This is another vital aspect of this construction, and for such utmost care was taken, especially in the aspect of mixing of sand, cement and the aggregates. The strengths of any concrete lies on the mix and the mixture of the concrete. The mix may be 1:1:1, but if it is poorly mixed, it will not give the desired result.
- 15. FILLING OF FOUNDATION WITH LATERITE (JULY, 2020)
Filling of the foundation with Laterite took the whole of July, 2020 to accomplish. Nobody envisaged that the foundation will consume the quantity of Laterite it consumed. It took 400 trips of Mack Trucks to cover the whole of the foundation, due to the depth of the foundation. The filling would not have been finished in 3 months, if done manually, hence the use of pay-loader to do the filling.
This report was prepared by Engr. Emmanuel Aguocha, the Resident Engineer.