Akobo Construction Field Report-draft.doc PDF

7/31/2019 Akobo Construction Field Report-draft.doc PDF

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Akobo field construction Report Page 1

ProjectCompound Improvement

For

Akobo Field Office

Undertaken by

Contractor: GASCO Limited

Compiled by: Ladu George Lambu

Construction Supervisor, SCI AKOBO.

Checked by: Stephane K,

Construction Consultant, SCI JUBA

Date: 6th

May 2012


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SCOPE OF WORKS

The Contractor was awarded the contract, number PB/135/11/UN on the first dayof February2012 to construct an office block, two separate latrines each with four

stances and the Chain link fence, to be completed within 90 calendar days upon

the date of the contract signature.

IMPLEMENTATION

From 8th

march 2012 the contractor arrived and took over the site. From the 9th

Between 10

of March the SCI logistics manager was requested about the local material

sources, whereby he had to assist in the local mobilization of sand and aggregatebut he was busy and could not make it for that day.

thand 16

th

From 17

of March (a duration of 6 days), there was no major activity

going on for the reason being that land Boundaries for SCI compound had not yet

been decided between the SCI and the local authority and the local materials had

not yet been fully mobilized.

th

Foundation works had to go on for three consecutive days till 20

of March, the foundation works started by setting out and excavation as

per the drawings within the defined boundaries as it had been agreed by the local

authorities and SCI management.

th

The foundation works proceeded immediately after the bulk materials had been

secured and delivered on site.

of March when

it was stopped after a decision taken by the contractor through the foreman to

switch to the mobilization of materials which had to do with the collection of sand

from River Meer area and local aggregates from the same area.

From the foreman, Tony, we were able to get information that all the rest of

materials apart from sand and local aggregates, were to come from Juba


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including; marrum / gravel , harder aggregates and the rest of the material to

complete the works . This was to take only 3 days for all the materials to be

delivered.

We found out that all the walling was done by use of cement/sand blocks made in

situ on site. Some of the blocks indicated that they were very weak and

crumbling. Well, the foreman had to explain as to why as such was happening for

the first batch of blocks before they were even used and he said that it was the

first trial test that was done by a 1:4 ratio (cement bag: wheelbarrow of sand)

instead of 1:3 mix ratio that is commonly used.

On the same note, the wall thickness done on site for the foundation walls (plinth

walls) for all the construction is 150mm compared to that in the drawing which is

specified as 400mm for the Office block as per the drawing and 200mm thickness

for the toilet walls.

The foreman had defended himself that it was all about the mould that was

delivered on site that gave him no option. The mould could make block sizes of

150x200x400mm compared to the expected 200x200x400mm solid blocks.

Basically the walls were built on edge instead of building on bed to achieve the

200mm desired thickness.

There was enough evidence that curing was not done effectively otherwise it

could have been the ratio that was poor on top of the clay impurities in the sand

that led to the poor quality of the first lot of the blocks that were made.

THE PROJECT WAS DELAYED

We looked at the time frame and got worried about the time left compared to the

works left to be done. The contract was signed on the 1st

of February 2012 and

the project duration is for only 90 days. This means that the contractor has only

the month of May to cover everything to turn key and handover.


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When we tried to track backwards, it was found out that work started onthe 8

th

The project commencement was earmarked when a team of 5 Masons(skilled laborers) and 6(unskilled laborers) Helpers and their foreman

arrived in Akobo.

of May 2012, which was one month and a week late ever since the

project was signed and we could not get any reason as to why this

happened that way.

On the other hand, the foreman explained that they had to wait foranother 6 days before the new SCI boundaries had to be negotiated

between the SCI admin and the local authorities.

That, rain had interrupted twice ever since the project started. This was inthe mid march when rain started at around 11:00 am and work came to a

standstill until the next day. The other occasion was in the first week of

April when it started raining at around 2:30pm and work couldnt proceed

until the next day.

The last delay was from the time when cement got finished and the workshad to come to a stand still waiting for the materials from Kampala. Our

estimation was for about a week when these materials had to reach Juba

and three days for the materials to reach Akobo from Juba. Fortunately,

the consignment was sent on Wednesday 1st

of May from juba and it

reached on the 4th

day of May 2012 to Akobo, the day after our arrival in

Akobo.


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TECHNICAL FINDINGS

HOW IT WAS DONE ON SITE FROM THE CONTRACT DOCUMENT

OFFICE BLOCK:

The plinth wall thickness is150mm,

The plinth wall thickness is400mm,

The Stud columns are 150mmx200mm,

The Stud columns are 400mmx400mm,

The RCC ground beam is150mmx200mm,

The RCC ground beam is300mmx300mm,

The marrum / Gravel layerthickness is 65mm,

The murrum / Gravel layerthicknesss is not indicated.

The DPM Ga 1000 PVC membranewas not provided,

The DPM Ga 1000 PVCmembrane was not

documented,

The BRC reinforcement Bars to theslab are R8 tied @ 370mm spacing,

The BRC reinforcement Bars areindicated as Y10 to be tied @

300mm spacing, The stirrups used are R6@300mm

spacing

The stirrups specified areR8@200mm spacing.

FENCE

The spacing of the angle line pits is3000mm c/c @ the depth of

600mm with diameter of 250mmon average.

121 pieces of 50x50x6mm AngleDelivered on site

The spacing of the angle line pitswas not indicated and the depth

of 400mm/ 500mm with a topcross section area of 300X300mm

was specified in the BOQ.

Required is 174 pieces of50x50x6mm Angle as per the


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BOQ to cater for struts and

Strainers for the fence

VIP LATRINE, 2No @ 4-stance

The deepest end of the pitexcavated is 4000mm from the

ground level.

The depth of the pit could not beread from the document i.e the

section detailed drawing for the

pit was missing from the

document.

The top section of the built pit is1500x4700mm internally and

1600mm depth from the ground

level. And the bottom section of

just mere excavated pit separated

by a 65mm thick slab is

790mmx4000mm and 2600mm

deep.

Ditto but the drawing planspecifies 900x4000mm top areaof the pit which differs from the

1300x2100x5000mm as per the

BOQ ,

The total excavated volume wascomputed to be 20m

The total volume to beexcavated was 28m

3

3per 4stance

pit as per the BOQ

The slab thickness to one of thetoilets near the office block was

made to be 65mm thick with Y12

rebar @ 300mm spacing and

covered by the welded wire mesh

on top.

The slab was specified to be100mm thickness for all the

toilets as per the BOQ.


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MATERIALS DELIVERED TO THE SITE

The last batch of the materials for the completion of the work arrived yesterday4

thMay 5, 2012 at around 3:00 pm, it took 3 days to reach AKOBO from Juba.

These included:-

Item Details Quantity Unit Remarks

1 Portland Cement, Rhino

Brand

250 Bags Non was damaged

2 Y12, Reinforcement bars 38 No

3 Iron sheets, Ga 28 pre-

painted maroon in color

145 Pcs

4 Welded Wire

mesh,120x240mm

3 Pcs

5 Wooded Door frames 8 Pcs

6 Softboards,122x244cm,10mm

thick

65 Pcs

7 Sadolin paints, Emulsion,

under coat

Jkans

8 Sadolin paints, Emulsion,

Final coat , cream

Jkans

9 Sadolin paints, Gloss

paint

Jkans

10 Sadolin paints weather 4 tins of Tin


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guard 20Ltr @

11 Metallic doors for VIPLatrines, 80cmx210cm

8 pcs

12 Flash Timber doors 4 pcs

13 Barbed wires,25kg Roll 3 Rolls

14 Main Gate

Metallic,4000x2100

1 No The small pedestrian gate

was not provided

15 Binding wire 10 Kg

16 Putty for glasses 2 Tins

17 50x50x6mm Angle bars 121 Pcs

17 Wood preservative 3 Jkans

18 Burnt clay Vent

bricks,220x112x75mm,Z

design

20 Pcs

19 Hand crashed Aggregate 10 Ton

20 Chain link 20 Rolls

21 Tension wire for the chain

link

3 Rolls

22 Ridge caps 25 Pcs

23 Valleys @ 2m long 5 pcs

24 2x6 common timbers 45 pcs


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27 1x9 Fascia boards 32 pcs One was damaged during

delivery

28 Metallic doors for the

latrine 750x2100mm sizes

8 pcs

29 1200x2200mm Double

door

1 pcs

30 Casement Windows

,1mx1.2m

22 No 9 windows were damaged

and need welding ,panel

beating repairs & painting

31 Assorted Wire Nails

6 25 Kgs

5 6 Kgs

4 7 Kgs

3 35 Kgs

2 5 Kgs

Roofing Nails 20 Kgs

Rubber washers Are missing, not brought

Hoop Iron 5 Rolls

DPC 5 Rolls


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Recommendations

Latrines:

We would recommend that the intended detailed section as part of the drawing

to be delivered for comparison or, to give us the precedence and guidelines in

controlling the already existing part. This would help us to make quick adjustment

as soon as possible. For example its quick not clear about the specific guide

concerning the pit depth and its top area. For the BOQ, it specifies1300x2100x5000mm and the drawing indicates 900x4000mm. The contractor

decided to excavate 4000mm as the pit depth from the ground level but in steps

as indicated in the table of observations above. Please find the attached sketches

of the as built sections of the toilets.

Office Block:

The recommended BRC from the drawing was y10 bars @300mm spacing c/c

fixed with binding wire contrary to what was done by the contractor where R8

bars spaced @370mm c/c was used. This is the point dragging us to another level

until we get a go ahead from the construction manager; the condition has already

been raised to his attention.

We had taken a quick decision of improvising by just reducing the spacing through

addition of more bars but the foreman had to confirm from his boss first.

And concerning the stirrups for the beams and columns, we were suggesting that

the use of R6 bars instead of the specified R8 would call for a reduction in their

spacing from the original 300mm to 150-200mm if only approved by the designer.


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On the other hand, for the wall, we had suggested to use the hoop iron

reinforcement @ every two courses to counter cracking.

DPM

The DPM, Damp proof Membrane was ignored by the contractor simply because

it was not part of the drawing and in the BOQ. We thought that the DPM is the

protective layer of the slab and the reinforcement against the raising moisture.

On the same note, it was not procured. If we could ask for precedence from the

designer, then we are safe.

FENCE

We would recommend that the fence needs more reinforcement in any way to

provide sufficient support to it laterally. This could be archived by improvising

more angle line bars for struts and the required strainers and terminal posts or

additional Timber poles @ not < 10m with deeper excavation depth.

WATER

More water will be needed for future use especially for concrete works andcuring. Curing is mandatory and requires relatively more water. The only nearest

water source point for clean water is the compound bore hole and it this calls for

a maximum storage and water reservation from the contractor.


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akobo 1: This the Arial view of one of the toilets.


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akobo 2: This side show how the soils are terrible, even up to the 2m depth, foundation cannot be guaranteed.

So what the contractor did was to excavate below to a depth of 1500mm for the wall seated on a slab as seen in

the photo, below this is a simple slab of 65mm made of 1:2:4 plain concrete according to the F/man.


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akobo 3: The slab thickness is 65mm, reinforced as per the F/man. We thought maybe the strength is currently

based on the formwork which is still below it.


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akobo 4: This is the layout of the foundation and the interest was in the spacing of the Rebars, the raise of the

plinth wall from the ground floor level.


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akobo 5: These are some of the materials which were brought in the last consignment, of course some were

damaged during transit especially the paint, windows and angle bars,


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akobo 6: (Left) are the hand crashed aggregate fetched all the way from Juba. (Right) are the stones collected

from the river banks.


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akobo 7: This is one of the blocks that were molded on site. It shows that sand is impure with clay particles and

rubbish. The quality could partially be improved by sieving sand before use.

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