Some important checklists for RCC slab and beams

The following checklists are extensively utilized for RCC slab and Beams.

1. Examine the bottom line, level & width of beam properly.
2. Examine the side line, level & plumb of beam properly.
3. Beam to beam measurements should be examined according to architectural drawings.
4. Individual level & diagonal of each slab bay should be examined properly.

5. The thickness level of slab should be marked with nails on the peripheral beam’s exterior sides.
6. Examine the thickness of slab and depths of beam properly.
7. Support props for slab & beam bottoms should arrange in line & plumb. Bamboo bracing should be accomplished at around 4′ ht from floor level. Support props for double staging terraces should be examined cautiously.
8. Line of external /peripheral beam’s sides should be examined & cross supported to get rid of buldging out of sides.
9. Junctions of columns & beam should be verified to make them water resistant.
10. De-shuttering oil should be provided to beam/slab shuttering.

11. Formwork of stair case should be examined for dimensions of tread and riser, level of treads, plumb of risers.
12. Reinforcement should be examined for beams and slab as per R.C.C drawing
13. Ensure to provide exact cover for bottom /sides of beams.
14. Proper cover should be provided for slab.
15. Electrical points, electrical piping (conduits)/fan hooks should be examined as per drawing.
16. Reduction of column according to drawing should be performed if any.
17. There should be exact numbers of chairs should be arranged for slab.
18. Dowels (if any) should be arranged for elevational feaures / future expansion.
19. Parapet (Pardi) bars should be provided for balconies/staircase etc.

20. Ring (stirrups) should be arranged at the free end of each column reinforcement.
21. Distances among plates /planks should be filled. Taping should be performed at ply joints for the protection of ply shuttering.
22. Before starting pouring work, consent of the architect and R.C.C Consultant should be obtained.
23. Prior to start concreting work, verify the accessibility of necessary labour strength, mixer, lift, vibrators, masons, weigh batcher, diesel/petrol and plastic sheets etc before start of concreting.
24. Hidden beams /inverted beams/cantilever beams should be examined properly.
25. Based on the approved drawings, verify the sunk.
26. Packing underneath support props should not be provided. As an alternative, single wooden plank should be inserted as packing.
27. For large slabs, exact location of concrete joints should be determined beforehand as per approval of RCC consultant.
28. Accessibility of raw material for concrete /RMC per grade of concrete, water , electricity should be examined beforehand prior to start concreting work.

29. Initially, concreting should be performed for the beams & then slabs.
30. Compaction of concrete should be accomplished with vibrators & tamping rods.
31. The top level of the slab should be completed with mason & there should be restrictions to walk on the fresh finished concrete.
32. Carpenter should be provided under the slab shuttering throughout concreting to keep the form work tight.
33. For protection against rains, large plastic sheets should be used to wrap finished concrete.
34. Cast 6 cube moulds for testing.
35. Curing of slab should be accomplished with ponding method by making ponds in cement & sand mortar (1:10) of size around 5′ X 5′. Curing of beams and slabs should be performed for 7 to 10 days or as suggested by the consultant.
36. Deshuttering of the exterior sides of the beam should be accomplished after 24 hours . Deshuttering of the inner sides of beam should be accomplished after 48 hours . Deshuttering of the beam bottoms should be accomplished after 14 days for beam lengths up to 3 M or as per suggestions of the consultant. Deshuttering of the slab should be performed after 7 days for slabs up to 3 M span or as directed by the consultant.
37. Finishing of honeycomb should be accomplished cautiously in front of engineer the next day.
38. Hacking of the beam sides, beam bottoms, slab bottoms should be accomplished within 1 or 2 days from deshuttering.
39. Date of casting and the number of slab should be painted on the front side beam.

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Published By
Rajib Dey
www.constructioncost.co
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How to perform audit of old structures

There exist several types of public buildings with over 30 years lifespan. The stability of these buildings is decreased significantly owing to decay in materials.

On the basis of the yearly tests conducted on each public building, the weaker buildings having age over 30 years should be detected and the Assistant Executive Engineer level Officer of the related department should dispatch the list to the superior officer of the level.

Then, an inspection at the level of superintending Engineer/EE should be performed for all such building and an extensive structural audit should be carried out.

The related department should hand over the structural audit to an accredited Institution / agency and the details of which are provided below:

Usually, the Structural Audit should be performed with the following steps:

Step 1: The Architectural and Structural plans of the building are important. There should be detailed structural calculations along with assumptions for the structural design.

Step 2: When the Architectural plans and Structural plans do not exist, the similar should be arranged on the basis of site observations.

Step 3: A building should be examined thoroughly as follow :-

1. Any settlement in the building.
2. Cracks found in columns, beams and slabs.
3. Pictures of concrete disintegration and exposed steel reinforcements are useful.
4. Slight tapping with a hammer can disclose decay in concrete and wooden beams.

5. Erosion in reinforcement.
6. Status of Balconies – sagging, deflection, cracks.
7. Status of Architectural features.
8. Cracks in walls specifying swelling in R.C.C members or identification of erosion.
9. Leakages from terrace & Toilet blocks.
10. Leakages & dampness in walls which lead to cracks and corrosion.
11. Status of repairs & last repaired date.
12. What section of the structure was repaired?
13. Who was the Agency?
14. How much was incurred for repairs?
15. Are sanctioned Building plans available?

Step 4: Formulation of Audit Report:
Depending on the inspection on building, the Audit Report should be arranged.

Step 5: Tests Suggested:
It is vital that different types of tests are performed in the old buildings to get an idea about spreading of corrosion, distress and loss of strength in concrete & steel.

Step 6: Point out the major areas and repair them accordingly.



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Published By
Rajib Dey
www.constructioncost.co
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Basic differences among Prismatic Compass and Surveyors Compass

Compass belongs to an instrument that plays an important role to workout the direction of a survey line relative to magnetic north-south.

The magnetic north-south direction is treated as the reference direction and it is known as meridian (reference direction) and the angle among the line and the meridian is known as bearing. The compass is applied for calculating the direction of a line to simplify the surveying process significantly.

The variations among prismatic and surveyor’s compass are given below :-

Prismatic Compass

1. Graduation circle is attached to a broad type needle. Therefore, it will not revolve with the line of sight.
2. A prism is situated at viewing end.
3. Sighting and reading are performed concurrently.
4. The magnetic needle does not perform like an index.
5. The graduations are in whole circle bearing.
6. Graduations are pointed inverted as its reflection is examined via prism.
7. The reading is captured through a prism.
8. Tripod may or may not be applied. It can be persisted with a stretched hand also.

Surveyors Compass

1. Graduation circle is attached to the box. Si, it revolves with the line of sight.
2. No prism exists at viewing end except for a slit.
3. It is not possible to perform sighting and viewing all together.
4. Magnetic needle functions as index at the time of reading.

5. The graduations remain in quadrantal system.
6. Graduations are pointed directly. They are not inverted.
7. The reading is captured by directly viewing from top glass.

8. Tripod is necessary for being applied.

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Published By
Rajib Dey
www.constructioncost.co
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