Que2.11. What’s specification and its objects? Also explain its types.
Answer Specification A specification is a statement of particulars. Construction specifications may be defined as written instructions identifying( or limiting) and describing in detail the construction work to be accepted. Objects Following are the objects of specification
1. Contract Document Specifications serve as a contract document between the proprietor and the contractor, limiting and describing their liabilities.
2. companion to stab Specifications enable the estimators of the contractors to arrive at a fair price for the work involved.
3. Guide to administrators Specifications serve as a companion for the fabrication and installation of accoutrements and outfit. Types of Specification Following are the two types of specification
1. General Specifications
i. In general specifications, nature and class of workshop and names of accoutrements that should be used are described.
ii. Only a brief description of each and every item is given. It’s useful for estimating the design.
iii. The general specifications don’t form a part of contract document.
2. Detailed Specifications
i. The detailed specifications form a part of a contract document.
ii. They specify the rates, amounts and proportions of accoutrements and the system of medication and prosecution for a particular item of workshop in a design.
iii. The detailed specifications of the different particulars of the work are set independently and they describe what the work should be and how they shall be executed.
iv. While writing the detailed specifications, the same order sequence as the work is to be carried out is to be maintained.
Que2.12. bandy the significance of detailed specification.
Answer significance of Specifications Following are the significance of specifications
1. The cost of a unit volume of work is governed by its specifications.
2. Specification of a work is needed to describe the quality and volume of different accoutrements needed for a construction work and is one of the essential contract documents.
3. This also specifies the workmanship and the system of doing the work.
4. A work is carried out according to its specification and the contractor is paid for the same. Any change in specification changes the proffered rate.
5. As the rate of work is grounded on the specification, a contractor can calculate the rates of colorful particulars of workshop in tender with his procurement rates of accoutrements and labour. therefore tender rate without specification of workshop is unwarranted, deficient and invalid.
6. Specification is necessary to specify the outfit tools and shops to be engaged for a work and therefore enables to land them beforehand.
7. The necessity of specification is to corroborate and check the strength of accoutrements for a work involved in a design.
Que2.13. Write down a detailed specification of channel in excavation in foundation.
Answer Channel in Excavation in Foundation Following are the points consider in excavation in foundation
- Excavation Foundation fosses shall be dug out to the exact range of foundation concrete and the sides shall be perpendicular. , the sides If the soil isn’t good and doesn’t permit perpendicularsides.should be leaned back or defended with timber shoring.
- iii. shoveled earth shall not be placed within 1 m of the edge of the fosse .
2. Finish of Trench
i. The bottom of foundation fosses shall be impeccably leveled both longitudinally and obliquely and the sides of the fosse shall be dressed impeccably perpendicular from bottom up to the least consistence of loose concrete so that concrete may be laid to the exact range as per design.
ii. The bed of the fosse shall be smoothly doused and well rammed. redundant digging if done through mistake shall be filled with concrete at the expenditure of the contractor.
iii. Soft or imperfect spots shall be dug out and removed filled with concrete or with stabilized soil. , these should be If jewels or boulders are set up duringexcavation.removed and the bed of the fosses shall be leveled and made hard by consolidating the earth. Foundation concrete shall not be laid before the examination and blessing of the fosse by the mastermind- in- charge.
3. Water in Foundation Water, if any accumulates in the fosse , should be bailed or pumped out without any redundant payment and necessary preventives shall be taken to help face water to enter into the fosse .
4. fosse Filling After the concrete has been laid masonry has been constructed the remaining portion of the fosses shall be filled up with earth in layers of 15 cm and doused and well rammed.
5. dimension
i. The dimension of the excavation shall be taken in cu m( cu ft) as for blockish fosse bottom range of concrete multiplied by the perpendicular depth of foundation from ground position and multiplied, by the length of fosses indeed though the contractor might have shoveled with leaning side for his convenience.
ii. Rate shall be for complete work for 30 m lead and1.50 m lift, including all tools and shops needed for the completion of the workshop.
iii. For every redundant lead of 30 m and every redundant lift of1.5 m separate redundant rate is handed.
Que2.14. Write down a detailed specification of cement concrete 1 2 4.
Answer Detailed Specification of Cement Concrete 1 2 4 Following are the point consider in specifications of cement concrete 1 2 4
1.Accoutrements Aggregate shall be of invert accoutrements and should be clean, thick, hard, sound, durable,non-absorbent and able of developing good bond with mortar.
ii. Coarse total shall be of hard broken gravestone of determinedness or analogous gravestone, free from dust, dirt and other foreign matters.
iii. The gravestone cargo shall be of 20 mm size and down and all should be retained in a 5 mm square mesh and well graded similar that the voids do not exceed 42 per cent.
iv. For erecting work 20 mm hand and for road work and mass work 40 to 60 mm hand may be used. Fine total shall be of coarse beach conforming of hard, sharp and angular grains and shall pass through screen of 5 mm square mesh.
vi. Cement shall be fresh Portland cement of standard ISI, specifications, and shall have the needed tensile and compressive stresses and fineness.
vii. Water shall be clean and free from alkaline and acid matters and suitable for drinking purposes.
2. Proportion
i. The proportion of concrete shall be 1 2 4 as cement beach gravestone cargo by volume unless else specified.
ii. minimal compressive strength of concrete of 1 2 4 proportion shall be 140 kg per sq cm( 2000 lbs/ sq in) on 7 days.
iii. Gravestone total and beach shall be measured by volume with boxes.
iv. Cement need not be measured by box, one bag of cement( 50 kg) should be considered as 1/ 30 cum. Size of measured box may be 30 cm × 30 cm × 38 cm or 35 cm × 35 cm × 28 cm original to content of one bag of cement.
3. Hand Mixing Mixing shall be done in masonry platform or distance iron charger.
ii. For concrete of 1 2 4 proportion, first two boxes of beach and one bag of cement shall be mixed dry completely and also this dry blend of cement and beach shall be placed over a mound of 4 boxes of gravestone total and the whole mixed dry turning at least three times to have invariant blend. iii. Water shall also be added sluggishly and gradationally according to water cement rate with a water- can while.
iv. The whole shall be mixed completely turning at least three times to give a invariant concrete.
4. Machine mixing Stone cargo beach and cement shall be put into the cement concrete mixer to have the needed proportion.
ii. Mixer, the machine shall also be revolved to blend accoutrements dry and also water shall be added gradationally to the needed volume.
5. Formwork Formwork centering and shuttering shall be handed as needed, as per standard specifications before laying concrete to confine to support or to keep the concrete in position.
ii. The inner face of shuttering shall be waxed to help concrete sticking to it.
iii. The base and formwork over which concrete to be laid shall be doused by smattering water before concrete is laid.
iv. Forms shouldn’t be removed before 14 days in general, side forms may still be removed after 3 days of concreting.
6. Laying Concrete shall be laid gently( not thrown) in layers not exceeding 15 cm and compacted by cascading with rods and tamping with rustic tampers or with mechanical wobbling machine until a thick concrete is attained.
ii. Concrete shall be laid continuously, if laying is suspended for rest or for the following day the end shall be leaned at an angle of 30 ° and made rough for farther jointing.
iii. When the work is proceeded , the former graded portion shall be planed, gutted and doused and a grout of neat cement shall be applied and the fresh concrete shall be laid.
iv. For consecutive subcaste the upper subcaste shall be laid before the lower has set.
7. Curing After about two hours laying when concrete has begun to harden, it shall be kept damp by covering with wet gunny bags or wet beach for 24 hours, and also cured by submerging with water making slush walls7.5 cm high or by covering with wet beach or earth and kept damp continuously for 15 days.