ensuringquality
TRANSCRIPT
Ensuring Quality in civil Construction
Presented by :
Er. P. Das,(M.Tech.Civil )A.E, Jatni.Under the guidance of
Er. Mahendra Kumar Mohanty
EE,DRDA,KHORDA
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Definition of QualityQuality means excellence.
It is thus a philosophy rather than a mere attribute.
The difference between two objects
is judged by their qualities.
We set some standards which
determine the level of acceptability.
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Quality control:-
Quality control means rational use of resources. Quality control procedures implement:-
appropriate mixing, proper compaction, correct placement and
adequate curing. Quality control prevents temptation of over
design.
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Quality Controls-----
Quality control ensures:- strict monitoring of every stage of
concrete production and rectification of faults. Quality control reduces maintenance
costs.
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Plan, Do, Check and Act cycle for assuring quality
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Plan :-quality
Do :- Working systematically
Check:- checking with non conformance Act :-Upon the result
The cement sand mix in the mortar and brick masonry is made quite early, prior to its use and in
larger quantities than required.
The construction materials like sand, bricks,
Aggregate etc are not washed and are full of
deleterious material and dust. 7
Knowing the 20 No mistakes occurr during construction phase ( for planning purpose )
construction mistakes
Compaction of bottom strata in foundation work is not carried out.
During concreting of footing, the concrete is poured at a height greater than 1m.
Generally, trapezoidal footings are resorted to where concrete is never vibrated.
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construction mistakes
Reinforced concrete column, being an important part of the structure are neither mechanically vibrated nor machine mixed.
They are cast in short lifts with increased number of joints.
Cover to reinforcement in column, beams and slabs is insufficient.
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construction mistakes
No cover to reinforcement in contact of the ground
Misalignment of column at foundation level and rectification at higher level, leading to eccentric loading.
Reinforced coping at plinth level being an important barrier to dampness is never densely cast.
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The plinth filling is never carried out in layers nor compacted.
At the joints of Reinforced concrete and brick masonry, either :-
the RC surface is not roughned or filling of mortar at the joint is not
evident.
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construction mistakes
The joint of brick masonry at larger height are improperly racked.
Mixing ratio in plaster and brick masonry is not maintained.
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construction mistakes
In the case where beams are cast prior to slabs :
In large slabs, the concrete in beams starts setting before casting of RC slab.
The concrete spilled on the sides of beams while casting is never removed which gets set subsequently
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construction mistakes
Reinforcement of RC column is kept exposed above RC slab.
Hacking to concrete surface is poorly done prior to Plastering.
Bearing to lintels on both the ends is not sufficient.
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construction mistakes
In load bearing structure ,secondary beams are resting directly on the walls giving point loading.
Proper care for uplift pressure in black cotton soil is not taken in by proving with
ground beam Combined footing
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construction mistakes
The above 20 no construction mistakes may result in
Cracks in concrete.Improper bonding between concrete and brick masonry.Spillage of plaster.Dampness of walls.Leakage of slabs.Cracks in brick masonry.Settlement of foundation and walls.
Result of mistakes.
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Causes for poor quality can be summarized as ignorance, poor materials, poor design,
poor detailing, poor workmanship, improper quantity of cement, improper concrete mix,
excess water, inadequate compaction, substandard forms, inadequate curing,
inadequate cover, poor construction practices, poor supervision and above all
lack of technical knowledge.
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Causes of mistakes
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Description of deficiency
Frquency of occurrence
Applicable application
% frequency occurrence
Inadequate suspended reinf conc beam depth
6 13 46%
missing column reinf 1 17 6%retaining wall reinf on wrong side of wall 11 1 100%inadequate cantilever reinf anchorage 1 1 100%
Effectiveness of the Existing system in quality vulnerability reduction
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Entity
Block Development Offi cer
Assistant Engineer
JE
Executive Offi cer
Executant
Sanjojaka
only interested in profit as 10%, profit is not in estimate
Can't be believed,not accountable
Comments
Check only the progress
Monitor progress,Check quality,encourage public participation
Estimate,Execute,Check only during his presence
Does not Check quality
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With the increase of quality of design, cost increase is exponential but value addition initially increases, but starts saturating at of some point. Hence the optimum cost is arrived when slope of both the curves is same .
Relation between Quality and Cost
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One can note that with the increase of quality of construction, cost of quality control gets saturated. Thus we can arrive at optimum quality for minimum cost from total cost of the construction.
Economics of Quality of Conformance
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Case Study
Project : Community CentreScheme : MPLADGP: GangapadaEst.Cost :-3.96 LakhSteps taken : The entire reinforcement was wrong, and was removed as per the design requirementOf the slab
CONCLUSIONS:
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100% quality in PR Deptt. can not be controlled it can only be managed by :-Immediate Execution of the work
Use of machinery and technology
Experienced quality engineer
Distributing quality manuals to the peopleMore no of supervision to the site