Report on Igbosere

8/4/2019 Report on Igbosere

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CYRUSSTRUCTURAL ENGINEERING, CONSTRUCTION AND PROPERTIESKM 38 Lagos/Abeokuta Exp. Rd, Owoyemi House, Sango Ota, Ogun State, Nigeria.Email:[email protected] Mobile: +234-08034006525;+234-07036438781

Postal: P. O. Box 1814, Ota, Ogun State

Our Ref CR/008/13 Your Ref Date 7th

September 2011

The Managing DirectorGT Homes, 28 Saka Tinubu Street,

Victoria Island, Lagos.

Sir,

REPORT ON SITE VISIT TO THE HIGH RISE PROPERTY SITUATED

AT 38/40, STRACHAN STREET, OFF IGBOSERE ROAD, OBALENDE,

LAGOS STATE

PREAMBLE

The said property is a seven storey building with a penthouse which was

affected by an inferno. The ground and first floors were un-affected by the

inferno. The effects of the flames on the structural members were noticeable at

the second floor and on to the seventh floor as well as the penthouse. The

destructive effect of the fire varied from floor to floor.


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DETAILED OBSERVATIONS

Table 1: Second Floor

s/n Defect Description Recommended Solution

1 Spalling effects could beobserved on the cover to

the concrete walls and

the partition sandcreteblockwalls.

The partition sandcrete blockwalls (which hasbeen weakened by the flames) should be

completely removed and replaced. The

damaged mortar cover on the concrete wallsshould also be exfoliated completely and

replaced with high grade mortar

2 The lintel to the door thatleads to the main hall

(close to the internalstaircase) has beenweakened

It can be re-cast

3 Some portions of the

cover to the top slab had

fallen off

See general observation No. 1

Table 2: Third Floor


1 The partition wall on this floor (close to theinternal staircase) are extremely weakened

and may collapse any moment or at theslightest disturbance (Figure 1)

It should be removed withutmost caution to avoid

impact on the floor slab

2 Portions of the top slab reinforcement are

seriously compromised. Part of thereinforcement is twisted and weakened(Figures 2 and 3).

See general observation No.

2 and generalrecommendation No. 2

3 The lintel to the door that leads to the main

hall (close to the internal staircase) has beenweakened

It can be re-cast


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Fig. 1: Partition wall close to the stairwell about to disintegrate

Fig. 2: Seriously compromised slab reinforcement


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Fig. 3: Slab affected by the flames

Table 3: Fourth Floor


1 The partition walls on this floor areweakened

All internal partition walls are tobe removed and replaced

2 Spalling effects could be observed on

the covers to the concrete members(Figure 4)

See general recommendation

No. 1

3 The lintel to all the doors on this floor

are weak

They should be re-cast

Figure 4: An exposed bottom reinforcement in a beam


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Table 4: Fifth Floor

s/n Observation Recommendation

1 The structural members on this floor wererelatively unaffected by the flames with theexception of soot on the walls and top slab.

All concrete covers were in place and noexposed reinforcements could be observed.

The soot on the walls andceiling on this floor may bescrubbed off and

redecorated

2 The partition walls are also in order.

Table 5: Sixth Floor


1 Portions of the top slab and beams haveexposed reinforcements

See generalrecommendation No. 1

2 The partition walls showed signs of

weakening

See general

recommendation No. 3

Table 6: Seventh Floor

s/n Defect Description Recommended

Solution

1 The effect of the fire on this floor is not much.However, some minor portions of the top slab and

beams have lost their cover to the reinforcements

See generalrecommendation No.

1

2 Portions of the flat roof are leaking It could be felted

Table 7: Penthouse

s/n Observation Recommendation

1 The structural members on this floor were

relatively unaffected by the flames with theexception of soot on the walls and top slab.All concrete covers were in place and no

exposed reinforcements could be observed.

The soot on the walls and

ceiling on this floor may bescrubbed off andredecorated

2 Portions of the flat roof are leaking It could be felted


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Table 8: Others minor observations


1 The perimeter fence at the back of thebuilding is weak and about to fall on thebuilding behind the property.

The wall should be removedand replaced to avoid thesecondary cost of repairing an

adjacent building

2 The septic tank to the property (whichwas cleverly covered with concrete slab)appears filled up. It could be observed

through the vents on the floor just in frontof the generator house

The waste matter here couldbe suctioned away

GENERAL OBSERVATIONS

1. The flames had very serious impact on the partition walls and causeddamage to the covers to much of the concrete structural members on the

identified floors.

2. The greatest structural concern in this entire property is on the third floortop slab (the base of the fourth floor slab).

3. The effect of the fire appeared to be concentrated around the elevatorshaft area. Access could not be made into the elevator because it waslocked.

4. The structural integrity of the building in general is still intact.

GENERAL RECOMMENDATIONS

1. All damaged covers to concrete members should be replaced with highgrade mix of mortar.

2. The damage to the third floor top slab (Table 2, No. 2) demands that allextreme loadings on this isolated portion (situated between the two beams

that flank the stair well) should be avoided. Definition of extreme loading

here include but is not limited to:


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i. Crowds such as church activities where large numbers of excitedpeople jump around.

ii. Heavy machineries such as printing presses etc.

This problem can be remediated by considering two alternatives.

i. Cut off the slab in the seriously affected area using concrete saw.However, the attendant vibrations on other weakened sections of

the property and the aesthetic appeal would not be welcome. So

this leads to the second and more welcome solution.

ii. Replace the cover to the slab but cordon off the weakened sectionon the fourth floor using light weight aluminium partition and just

leave access ways for people to pass from one section of the floor

to another. That way, no dead loads would be imposed on the

affected slab.

3. All affected partition walls should be removed and replaced.4. Further investigation should be conducted on the elevator systems and

fire installation systems by specialist mechanical and electrical Engineers.

Yours faithfully,

Dr. David Omole (PhD, MNSE, COREN Reg.)

For: CYRUS

Report on Igbosere

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