Inspectan esitys Deep Foundation Technologies konferenssissa Instiassa 2014. Inspecta's presentation in the Deep Foundation Technologies conferens in India 2014.

1. 1 December 17, 2014
DFI INDIA 2014

2. DFI INDIA 2014
1. Background
•
Typical soiltypes in Finland
•Piling methods used in Finland
•Used piling equipment
•Piletypes
•Geotechnical and structural design
2. Case 1: Railway project ”Kerava-Lahti” direct line
3. Case 2: Construction project ”Porin puuvilla” shopping center
4. Conclusions
2 December 17, 2014
The use of driven precast concrete piles in Finland

3. Finland
Population: 5 445 883 (2013)
Capital: Helsinki
Weather: usually bad (below zero)
Soil conditions: Relatively easy
•
Interior hard soils moraine and bed rock usually
relatively low
•
With coastlines ususally clay layers
10-50 m and bedrock
3 15 November 2013
DFI India 2014
The use of driven precast concrete piles in Finland

4. DFI INDIA 2014
Soil conditions in Finland
•
Typical soil layers from bottom
–
Bedrock and moraine
–
gravel and sand
–
Silt and clay
–
Topsoil
•
The load bearing layer for piles are usually moraine or bedrock (usually in 10 to 20 m, with coastline up to 50 m)
4 December 17, 2014
The use of driven precast concrete piles in Finland

5. DFI INDIA 2014
Used piling methods in Finland:
•
Driven Precast concrete piles (most common)
•
Driven Large diameter steel pipe piles (most common in the Bridges)
•
Driven small diameter steel pipe piles (small buildings, and to replace concrete piles when use is not reasonable)
•
Drilled steelpiles (usually in special soil conditions / special constructions)
•
Jacked small diameter steel pipe piles (used usually in conservation or underpinning)
•
Bored piles (not commonly used)
5 December 17, 2014
The use of driven precast concrete piles in Finland

6. DFI INDIA 2014
Piles are usually driven with 4 t or 5 t hydraulic hammers
•
The pile cushion is used to reduce tension waves in the piles and to prevent pile head damage
•
Pile cushion usually abot 10-15 cm of wood (birch or beech)
•
Dropheight usually 0,2-0,5 m depending pile lenght
•
End bearing piles are usually driven to 10-30 mm / 10 blows (usually the total amount of blows to pile varies from few hundred to thousand)
•
Maximum lenght of the pile element is limited to 15 m
•
In Finland at the moment only Junttan Hammers are in use in this hammer category
6 December 17, 2014
The use of driven precast concrete piles in Finland

7. DFI INDIA 2014
December 17, 2014
7
The use of driven precast concrete piles in Finland

8. DFI INDIA 2014
Standard pile types
•
Standard pile types used in Finland are 250x250 mm, 300x300 mm and 350x350 mm
•
There are also few differend kind of reinforcement in the piles, depending on the pile loads
•
Conrete strenght 45 to 50 MPa
•
Reinfocement A500HW / A700HW
•
The lenght of the pile elements available from 3m to 15m
8 December 17, 2014
The use of driven precast concrete piles in Finland

9. DFI INDIA 2014
Pile splices
•
In Finland the mechanical splices are used for precast concrete piles
•
The structural design of splice is designed so, thet splice has the same moment capacity as the pile
•
Splices are tested according to European standard EN 12794 (Impact blow test and bending test)
9 December 17, 2014
The use of driven precast concrete piles in Finland

10. DFI INDIA 2014
EN 12794:
10 December 17, 2014
The use of driven precast concrete piles in Finland

11. DFI INDIA 2014
•
Pile is first driven to bedrock or as in the picture steelbox which lies on a concrete block.
•
1000 blows with 28 MPa average compression stress (stress is measured for example with PDA strain transducers during the test)
•
The inclination between Joint halves is measured at the start of the test and after 500 blows and at the end of test (which should be less than 1:150)
•
After impact blow test pile is lifted from the ground for further tests
11 December 17, 2014
The use of driven precast concrete piles in Finland

12. DFI INDIA 2014
Impact blow test and bending test
12 December 17, 2014
The use of driven precast concrete piles in Finland

13. DFI INDIA 2014
Rock shoe
•
In Finland the rock shoe is used in the most cases (if pile is supposed to support on bedrock or stony soil)
•
Rock shoes are tested with Impact blow test and bending test (national requirement – same impact load test as for he splice)
13 December 17, 2014
The use of driven precast concrete piles in Finland

14. DFI INDIA 2014
Geotechnical Design according to EN 1997: Eurocode 7
Design load  design resistance
•Charasteristic value of resistance is aclculated with correlation factors
•Desugn value of resistance is calculated with partial safety factor
14 December 17, 2014
The use of driven precast concrete piles in Finland

15. DFI INDIA 2014
Geotechnical Design according to EN 1997: Eurocode 7
Correlation factors from National annex
1.
Static load test
2. Dynamic tests
3. Calculations from soil investigation data
15 December 17, 2014
The use of driven precast concrete piles in Finland

16. DFI INDIA 2014
Geotechnical Design according to EN 1997: Eurocode 7
Partial safety factors factors from National annex:
Pile toe (Compression) 1,2
Pile shaft (compression) 1,2
Pile total (compression) 1,2
Pile shaft (tension)
Short term 1,35
Long term 1,5
16 December 17, 2014
The use of driven precast concrete piles in Finland

17. DFI INDIA 2014
The most common way in Finland to make dynamic tests for the pile and make the geotechnical design.
For example the maximum design load of 300c pile is 1124 kN and 50% of piles will be tested on site:
In tests the target capacity (mean)1,45*1,2*1124 kN = 1956 kN (min value 1753 kN)
In this case the geotechnical safety factor is 1,74 (there is also safety in the loads so total safety factor is about 2,4-2,6)
17 December 17, 2014
The use of driven precast concrete piles in Finland

18. DFI INDIA 2014
18 December 17, 2014
The use of driven precast concrete piles in Finland

19. DFI INDIA 2014
The end of drive criteria could also be calculated with wave analysis program
•
Pile is asssumed to be end bearing pile 80% of resistace is on toe
•
Hammers and hammer cushions are taken from programs database
•
It is assumed that pile cushion is a bit worn (not new, but not at the end of life)
•
Soil parameters (quakes and damping factors) are taken from resarch results from Finland and Sweden
19 December 17, 2014
The use of driven precast concrete piles in Finland

20. DFI INDIA 2014
December 17, 2014
20
The use of driven precast concrete piles in Finland

21. DFI INDIA 2014
21 December 17, 2014
The use of driven precast concrete piles in Finland
End of driving criteria is calculated with wave analysis program for 4 and 5 tons hammers (non accelerated and accelerated hammers) and different pile lenghts.
•
If you have 20 m piles (250a) and accelerated 4 tons hammer and the pile design load load 605 kN (PTL3), you should drive the pile to 15mm/10blows with 0,25 m dropheight to meet the requirements.

22. DFI INDIA 2014
22 December 17, 2014
The use of driven precast concrete piles in Finland
How about with neighbour countries to Finland:
•
Sweden and Norway uses quite similar methods for piling (the most popular is to use driven precast concrete piles). In both countries Eurocode is used for design, but both have also national codes for piling (Norway: Peleveiledning Sweden: Bro)
•
In Baltic Countries (Estonia Latvia and Lithuania) precast concrete pile is not so popular, CFA-piles and steel pipe piles are used even commonly
•
In Russia all kind of piling methods are used. When using pre cast concrete piles no mechanical splices are used. Piles are spliced by welding joints (casted steel plates in the pile heads)

23. DFI INDIA 2014
Case 1: Direct line Kerava-Lahti
•
Lenght of the track 74 km (totally new track 63 km)
•
Maximum speed on track 220 km/h
•
Bridges 76
•
About 12 km track runs on a bridge or a bridge-like reinforced conrete slab
•
Over 700 km of driven concrete piles (63 000 m³)
23 December 17, 2014
The use of driven precast concrete piles in Finland

24. DFI INDIA 2014
Case 1: Direct line Kerava-Lahti
•
Shedule for piles 12/2002 to 5/2005
•
Track ready to use 9/2006
•
Budget 331 M€
Quality control for piles:
•
Pile capacity will be tested dynamically from 2,5% of all piles
•
Integrity test will be done to all piles with low strain method
24 December 17, 2014
The use of driven precast concrete piles in Finland

25. DFI INDIA 2014
Dynamic tests:
•
In year 2002-2005 eurocode was not used in Finland,
•
The national geotechnical design was still used which based on total safety factors
•
Most of the piles were 300x300 and the allowable load for piles was 810 kN
•
The total safety factor of 2,0 was used with dynamic tests so the target capacity in the dynamic measurements was 1620 kN
25 December 17, 2014
The use of driven precast concrete piles in Finland

26. DFI INDIA 2014
Dynamic tests:
•
During the years 2003-2005 totally 407 dynamic tests were made for the concrete piles (Tampere University of Technology)
•
The target capacity were 1620 kN and the end of drive criteria varied from 15- 25 mm / 10 blows (depending on hammer, dropheight, lenght of the pile and soil conditions)
•
Maximum leghts about 40 m and shortests piles approximately 8 m
26 December 17, 2014
The use of driven precast concrete piles in Finland

27. DFI INDIA 2014
Integrity testing for the piles were made by low strain method
•
It is possible to see major defects in the pile
•
Sometimes the pile splice disturbs the signal and the lower pile segments can not be seen in the velocity curve
•
Signal is sometimes ”noisy” and filters shoud be used so that main things are still visible (also damages can be filtered, which is not the intention)
•
Sometimes signal has to be magnified to get the toe reflection
•
The new ”classification” of damages was introduced in this project to make reporting easier
27 December 17, 2014
The use of driven precast concrete piles in Finland

28. Low Strain method
DFI India 2014
09/09/2014 Teemu Riihimäki
Pile lenght L
2L/c
Sttress Wave is caused by hand held hammer, and at the same time accreleration is measured on the top of the pile
Damage is detected at time 2x/c
Toe reflection at time 2L/c
Damage at depth X

29. DFI INDIA 2014
December 17, 2014
29
The use of driven precast concrete piles in Finland

30. DFI INDIA 2014
During the years 2003-2005 totally 13 725 integrity tests were made for the concrete piles (Tampere University of Technology)
•
The percentage of rejected piles was less than 0,5%
•
Most of the piles damaged during the driving especially in the soils which contained boulders and stones
•
Sometimes the pile cushion was the reason for the damages
•
Some of the piles were damaged after driving, when excavators were digging the soil around piles
30 December 17, 2014
The use of driven precast concrete piles in Finland

31. DFI INDIA 2014
As a conclusion
•
The railway was manufactured in schedule and in the budget
•
The piling with driven prefanricated concrete piles was a sucsess in this project
•
In the sites was in the ”best” time about 20 piling machines
•
At the moment 79 trains / day and about 1 million passengers per year
31 December 17, 2014
The use of driven precast concrete piles in Finland

32. DFI INDIA 2014
Case 2: Puuvilla shopping center
•
Totally 100 000m2 shopping center
•
Rental shopping area 43 000 m2
•
Amount of shops 75-85
•
Budget 110 meur
32 December 17, 2014
The use of driven precast concrete piles in Finland

33. DFI INDIA 2014
Case 2: Puuvilla shopping center
•
Piling schedule 1/2013 -5/2013
•
Totally 3000 piles (about 100 000m)
•
Piletypes 250x250, 300x300 and 350x350 average lenght 33m (two splices, three pile elements)
Quality control for piles:
•Pile capacity will be tested dynamically from 2% of all piles (about 60 piles)
•Piles design loads
–250x250mm 513 kN target capacity 1,6*1,2*513 kN = 985 kN
–300x300 mm 741 kN target capacity 1,6*1,2*741 kN = 1423 kN
–350x350 mm 1008 kN target capacity 1,6*1,2*1008 kN = 1935 kN
•Integrity test will be done if on site quality management or piling contactor suspects defects on piles
33 December 17, 2014
The use of driven precast concrete piles in Finland

34. DFI INDIA 2014
Typical measured stresswaves:
34 December 17, 2014
The use of driven precast concrete piles in Finland

35. DFI INDIA 2014
Integrity problems after excavating
•
After excavating the piling contactor suspected problems with driven piles
•
Integrity tests were made to find out if piles had been damaged during the excavation
35 December 17, 2014
The use of driven precast concrete piles in Finland

36. DFI INDIA 2014
December 17, 2014
36
The use of driven precast concrete piles in Finland

37. DFI INDIA 2014
Integrity problems after excavating
•
After excavating the piling contactor suspected problems with driven piles
•
Integrity tests were made to find out if piles had been damaged during the excavation
37 December 17, 2014
The use of driven precast concrete piles in Finland

38. DFI INDIA 2014
As a conclusion
•
The Shopping center was in schedule and the costs were like in budget
•
Only few (about 10 piles) of 3000 piles damaged during the installation or other way
•
In this case the piling schedule was quite tight and at the best time 5 piling machines were driving at the same time in the quite smal area
•
Piles came from 3 different factories to make the schedule possible
38 December 17, 2014
The use of driven precast concrete piles in Finland

39. DFI INDIA 2014
Conclusion driven precast concrete piles in Finland
•
Driven precast concrete piles are the most economical solution in most cases in Finland about 75% of projects is made by precast concrete piles
•
Pile type should be selected correctly to soil conditions, lots of different solutions shoud be considered (There is no one right solution which fits everytime)
•
Shedule and budget are important (Time is money!)
•
Standard pile types makes deign easier
•
Testing is important (integrity and the capacity of the installed pile is the main issue)
•
Quality is important during the whole piling process (next slide)
39 December 17, 2014
The use of driven precast concrete piles in Finland

40. 40 December 17, 2014
Trust and quality in each step of the piling process
Final construction
•
Final construction is as designed and safe
Piling machine
•
Quality of manufacturing
•
Inspection of machine
•
Suitability of piling machine to the site conditions and piletype
Pre- construction phase
•
Design of construction in accordance standards
•
Setting quality limits for the final construction
•
Setting testing methods for the quality
Construction phase
•
Supervision
•
Monitoring
•
Testing of the driven piles
•
Capacity
•Integrity
Pile
•Quality of materials
•Quality of pile parts manufacturing
•Quality of manufacturing piles
•Testing of the piles, pileparts and materials

41. DFI INDIA 2014
December 17, 2014
41
The use of driven precast concrete piles in Finland
Thank you !

42. 42 December 17, 2014