Difference between revisions of "Construction-of-Low-Cost-Houses/C2/Laying-Foundation-bed-Concrete/English"
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Revision as of 15:40, 7 March 2024
Title of the Script: Laying Foundation Bed Concrete
Authors: Dr. Narsingh Varma, Chitra Balaji and Madhuri Ganapathi
Key words: Concrete spreader, Float, Level water tube, Spirit level, Bump Cutter, Screed, Safety shoes, Hand gloves, laitance, hessian cloth, video tutorial.
| Visual Cue | Narration |
| Slide Number 1
Title Slide |
Welcome to this Spoken Tutorial on Laying Foundation bed Concrete. |
| Slide Number 2
Learning Objectives |
In this tutorial we will learn about:
|
| Slide Number 3
Pre-requisites |
To practice this tutorial, learners should be familiar with basic construction methods.
For the prerequisite tutorials, please visit this site. |
| Slide Number 4
Details of foundation bed concrete |
Let us now learn about general terms on foundation bed concrete. |
|
13. details of foundation bed foundation bed laying bed concrete |
Foundation:
It is the lowest part of the building that is in direct contact with the soil. It transfers load from the superstructure to the soil safely. Foundation bed: The soil immediately beneath the foundation of a building is foundation bed. In load bearing structures, PCC has to be laid at the foundation bed after excavation. |
| Slide Number 5
Purpose of Laying PCC |
The purpose of laying of PCC at foundation bed is to:
Level the undular surface of excavated soil. Provide firm surface to the foundation More information on this is given in the Additional reading material. |
| Slide Number 6
Materials and Tools Required |
Materials and tools needed for laying foundation bed concrete. |
| copy of 1 ,copy of 2 copy of 5b, copy of 13.a
1.cement concrete 1a.cement concrete |
The materials are: Cement, sand, 20 mm and 10 mm coarse aggregates and water.
These ingredients are mixed in the ratio 1:3:6 to make plain cement concrete. Concrete mix can vary as per local technical guidance and site conditions. |
| Narration
add text on plain base |
Tools required for foundation bed concrete. |
| 2.concrete spreader
2a.concrete spreader 2b.concrete spreader |
Concrete spreader
It is used to spread the concrete. |
| 3.float
3a.float |
Float
Float is used to level and spread the concrete. It is made of a wooden strip with a wooden handle. |
| 4.Trowel | Trowel
Trowel is a tool for leveling and finishing the concrete. It is made up of a steel sheet with a wooden handle. |
| 5.water level | Level water tube
It is a thin, transparent and flexible plastic pipe. It is used to fix and mark the same height between larger distances. |
| 6.leveller | Spirit level
Spirit level is a tool used to check the surface level. It indicates whether the surface is horizontal or not. |
| 7.bump creed
7a.bump creed bumpcutter 1 bump cutter 2 |
Bump Cutter or Screed
It is used to level fresh concrete surfaces Leveling is done by cutting bumps and filling the depressions. It is also used to compact concrete, especially plain cement concrete. |
| Narration
Slide Number 7 Laying Foundation bed Concrete |
Let us see the steps involved in the process of laying foundation bed concrete.
All provisions mentioned in this tutorial are according to Indian Standard (IS) codes. |
| 10.Excavated pit
11.vibratory compactor 11a.vibratory compactor |
Preparatory work for bed concrete.
Remove loose materials if any from the excavated pit. Remove the top 10 cm soil, if the excavation was completed before. In case of filled soil, check and consolidate soil using a vibratory compactor. |
| 12.side shuttering
width of excavation width of excavation more width of excavation more 1 13.Details of foundation bed width of footing offset |
Side shuttering
Side shuttering helps to mould the wet concrete in place until it is set. If width of excavation is more than the width of bed concrete then, side shuttering is needed. side shuttering has to be provided at the required width of bed concrete. Width of bed concrete is width of footing plus 8 cm offset on sides. |
| 14.marking of shuttering
15. level tube 16. pouring of concrete pouring of concrete 1 pouring of concrete 2 17.spread concrete 17a.spread concrete |
Laying of concrete
Mark benchmarks of average 8 cm thickness from the base of the foundation pit. These markings are done at various locations along the excavated trench. This is done using a water level tube, to ensure uniform laying of concrete. The concrete mix is poured inside the foundation pit up to the marking. Care has to be taken while pouring the concrete into the foundation pit. The maximum permissible free fall of concrete should be 150 cm. Spread concrete uniformly using hoe or spreader up to benchmark level. |
| bump cutter1
bump cutter 2 19.latiance 20.sprinkle some cement 21.leveling 21a.21b.21c. |
Leveling and finishing
Remove local unevenness of concrete if any using a bump cutter. Consolidate concrete using screed. In case of formation of latiance, sprinkle dry cement over the foundation bed. Compact the foundation bed again to make it uniform.Laying and leveling must be completed when concrete is wet. |
| 22.hessian cloth
23. watering 23a.watering |
Curing
Cure concrete by covering it with wet hessian cloth. Keep the cloth wet by watering for few days before starting the masonry work. Curing must be continued till the start of masonry or minimum 14 days. |
|
24.personal protective gloves, gloves1 and gloves 2
24b.specs googles try to fit googles and shoes and gloves in page |
Safety Precautions
Always wear personal protective equipment on construction sites. Hand gloves provide safety to hands against construction chemicals. Shoes provide safety to legs against the toxic effect of cement. Shoes also prevent physical injury to the legs. Safety goggles prevent eye irritation from chemicals and concrete dust. |
| laying bed concrete
25.foundation bed level 26.segregation 27.bleeding 28.slump |
Quality Check
Check the foundation bed level using spirit level. It must be horizontal. PCC must be free from segregation and bleeding. Slump value of concrete should be 25 mm to 75 mm. |
| Slide Number 8
Reference codes |
These are the reference IS codes.
IS 456 IS 1904 IS 1080 |
| Only Narration. | With this we come to the end of this tutorial.
Let us summarise. |
| Slide Number 9
Summary |
In this tutorial we have learnt about,
|
| Slide Number 10
About Spoken Tutorial project |
The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it. |
| Slide Number 11
Forum for specific questions |
Please post your timed queries in this
forum. |
| Slide Number 12
Acknowledgement slide. |
The Spoken Tutorial Project was established by Ministry of Education, Government of India. |
| Slide Number 13
Thank you |
This tutorial is contributed by Dr. Narsingh Varma, Chitra Devi and Madhuri Ganapathi from IIT Bombay
Thank you for joining. |
