Backfilling 2014a-Lecture4
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This lecture discusses backfilling procedures for excavated structures. It defines backfilling as the activity that occurs after excavation to fill the excavated area. The lecture outlines the objectives of learning about backfilling clauses and how to determine which clauses apply. It then provides examples of excavating and backfilling footings and foundations for a simple guard house structure. It emphasizes the need to carefully measure excavation depths and backfill quantities for different areas. Finally, it provides exercises for students to measure backfill quantities for given structural details and footing configurations.
Backfilling 2014a-Lecture4
- 1. Lecture 4 – BackfillingLecture 4 – Backfilling Objectives:- 1.To learn the backfill to existing structures. 2.To relate the backfilling as per clauses in SMM2 3.To determine the various clauses applied to the backfilling Outcomes:- 1.Able to differentiate the different clauses used for backfilling 2.Able to write down the dimensions clearly.
- 2. BackfillingBackfilling It is an activity immediately afterIt is an activity immediately after excavation work.excavation work. This activity needs a lot of thinkingThis activity needs a lot of thinking and imagination.and imagination.
- 3. Once we have excavated the soilOnce we have excavated the soil what next?what next? Fig. 1 Excavated pit Fig 2. Excavated pit with footing and stump
- 4. Then what ?Then what ? Fig.1 Plan of a footing Fig.2 Section of a footing We need to backfill
- 5. After backfill what next?After backfill what next? A B Total excavated material( A + B = C) so A is the backfill quantity while C – A = B ( Qty. to be removed)
- 6. Lets look at a simple structureLets look at a simple structure F1 (1.00m x 1.00m ) Ground beam 150mm x 450mm Stump 150mm x 150mm Plan of a Guard house
- 7. Testing your eye sightTesting your eye sight View A View B View A View B GB1 GB2 GB3 GB4 GB1 GB4GB3
- 8. Before excavation we need to knowBefore excavation we need to know the different activities involvedthe different activities involved
- 9. 11stst . Measure the oversite. Measure the oversite excavation with average depth ofexcavation with average depth of 150mm150mm5.00m 5.00m
- 10. Area of oversite excavationArea of oversite excavation 5.00m 5.00m
- 11. Excavate for footingExcavate for footing
- 12. Section of excavationSection of excavation Ground level Base of footing level
- 13. Lets put in the structureLets put in the structure
- 14. Oversite excavation averageOversite excavation average 150mm thick150mm thick
- 15. Lets add in a ground floor slabLets add in a ground floor slab Slab 100mm thick
- 16. Lets look at the isometric view ofLets look at the isometric view of the structurethe structure Grd. Beam Grd. Floor slab Stump Footing
- 17. Look at the sequence carefullyLook at the sequence carefully A B C D
- 18. So when you measure backfill youSo when you measure backfill you shall consider carefully the differentshall consider carefully the different depth for the different areadepth for the different area Area 1 Area 2 Area 3 Area 4 Plan view of footing
- 19. Description for excavation, backfill andDescription for excavation, backfill and removal.removal. Excavate pit for footingExcavate pit for footing commencing from ground levelcommencing from ground level with plan dimension less thanwith plan dimension less than 1.25m and with depth not1.25m and with depth not exceeding 2.00m (5 nos.)exceeding 2.00m (5 nos.) Selected backfill to requiredSelected backfill to required formation level, spread, levelledformation level, spread, levelled and well rammed andand well rammed and consolidated.consolidated. Removing surplus excavatedRemoving surplus excavated material from site includingmaterial from site including transporting to contractor’s owntransporting to contractor’s own
- 20. Description for oversiteDescription for oversite excavationexcavation Oversite excavation average 200mmOversite excavation average 200mm thick including transporting top soilthick including transporting top soil to site to be determined by theto site to be determined by the architect for re-use.architect for re-use. Oversite excavation commencingOversite excavation commencing from ground level to a depth notfrom ground level to a depth not exceeding 250mm.exceeding 250mm.
- 21. Exercise no. 1: measure the backfillExercise no. 1: measure the backfill quantity using the descriptionquantity using the description providedprovided Footing F1 ( 12 nos.) 1000mm 1000mm 1.85m 650mm Stump 300mm x 300mm
- 22. Exercise no. 2- Measure the backfillExercise no. 2- Measure the backfill to footing F2to footing F2 900mm 900mm F2 ( 20 nos.) 1.65m 450mm Stump 150mm x 150mm Grd. Beam 125mm x 450mm 125mm 450mm Section of ground beam
- 23. Exercise no. 3 – Measure theExercise no. 3 – Measure the following:following: 1. Oversite excavation to footing F1.1. Oversite excavation to footing F1. 2. Excavation to Footing F1.2. Excavation to Footing F1. 3. Backfilling to Footing F1.3. Backfilling to Footing F1. 4. Removing surplus earth of footing4. Removing surplus earth of footing F1.F1. 5. Write down your answer in the5. Write down your answer in the correct format with correctcorrect format with correct description.description.
- 24. Footing F1 ( 25 nos.)Footing F1 ( 25 nos.) 950mm 950mm GL Oversite excavation 150mm depth 2.00m 50mm lean concrete Stump 250mm x 250mm 450mm GB 250mm x 600mm Plan Section