Parking garage, Gamletull. MDM-piles, pre-installation testing RÄTT FRÅN GRUNDEN!

Transkript

1 Parking garage, Gamletull MDM-piles, pre-installation testing Gamletull, MDM-pålar 1

2 CPT tests Gamletull, MDM-pålar 2

3 CPT test results Cone resistance Undrained shear strength Gamletull, MDM-pålar 3

4 Interpretation of soil layers WSP 4A BH 3 Gamletull, MDM-pålar 4

5 Loads & pile design Design parameters Total settlement 40 mm Differential settlement 1:800 Environmental impact 10 mm 20 mm Gamletull, MDM-pålar 5

6 Design of MDM piles and pile slabs Load limits Sliding Horisontal shear Contact pressure Load capacity MDM Geotechnical bearing capacity Total settlement Differential settlement Gamletull, MDM-pålar 6

7 Load characteristics Sliding Vertical 2100 kn (472 Kipf) Horizontal 200 kn (45 Kipf) Requiered friction 5.4 degrees!!!!! Result: Small stresses No reinforcement Shear Horizontal 200 kn (45 Kipf) Area 1.6*1.6=2.56 m 2 Shear strain 78 kpa (11.3 psi) Contact pressure Horizontal 200 kn (45 Kipf) Contact surface 1.6*2=3.2 m 2 Contact pressure 63 kpa (9.1 psi) Gamletull, MDM-pålar 7

8 Load capacity MDM piles Load 2100 kn (472 kipf) Load transfer surface, 2.56 m 2 Compressive stress 820 kpa (118 psi) Average compressive strength approx kpa (435 psi) Safety factor 3.7 Gamletull, MDM-pålar 8

9 Geotechnical bearing capacity, CPT evaluations Gamletull, MDM-pålar 9

10 Plaxis 3D analysis Vertical load CFA & MDM; V 4000 kn; H 0 kn Vertikal deformation Deformation [mm] CFA 15 m MDM 12 m Lasteffekt Dim. sättning MDM 15 m Vertikal lasteffekt [kn] Gamletull, MDM-pålar 10

11 Plaxis 3D analysis Horizontal load CFA & MDM; V2200 kn; H330 kn Horisontell deformation Deformation [mm] CFA 15 m MDM 12 m Horisontell lasteffekt [kn] Gamletull, MDM-pålar 11

12 Visual control Gamletull, MDM-pålar 12

13 Static load test (pull) single pile Gamletull, MDM-pålar 13

14 Results pull-out load test Force [kn] Deformation [mm] MDM Stag Plaxis 3D 7 m long pile 1 week curing time Shaft resistance 35 kpa (5 psi) Geotechnical bearing capacity 400 kn (90 kipf) Gamletull, MDM-pålar 14

15 Extraction of 2 MDM piles (1) Pullout force 510 & 610 kn (114 & 137 kipf) Age - 2 weeks Weight 45 kn (10 kipf) Density 2.27 ton/m 3 Shaft resistance 39 & 46 kpa (5.6 & 6.7 psi) Gamletull, MDM-pålar 15

16 Pile extraction (2) Pile 1 Length 5.7 m Bending 26 knm (19 kpff) Tension stress kpa (161 psi) Compressive stress 7.4 MPa (1073 psi) Pile 2 Length 4.5 m Bending 16 knm (11.8 kpff) Tension stress 700 kpa (101 psi) Compressive stress 4.7 MPa (681 psi) Gamletull, MDM-pålar 16

17 Pile extraction (3) Gamletull, MDM-pålar 17

18 Static load test MDM block (1) Gamletull, MDM-pålar 18

19 Static load test results MDM block A-B/12 Kraft [kn] Deformation [mm] Plint -6 m 9 piles, 12 m long (net) 4 mm permanent deformation at 2100 kn (472 kipf) Secant modulus (2100 kn) 2.5 GPa Gamletull, MDM-pålar 19

20 Static load test results MDM block B-C/5 Kraft [kn] Deformation [mm] Plint 9 piles, 16 m long (net) No permanent deformation at 2100 kn (472 kipf) Secant modulus (2100 kn) 6 GPa Titan tension piles pulled out at 2100 kn (472 kipf), test abandoned Gamletull, MDM-pålar 20

21 Description of work Grading Cut-off level +1.0 Widening of excavation Setting out Installation Piles to be installed with overlap; fresh in fresh Min 0.5 above cut-off Final grading Within hours Frost protection Curing 3 days Casting of slabs Form work Reinforcement Pouring of concrete Quality control! Gamletull, MDM-pålar 21

22 Construction guidelines Pile lengths Line A-B/12: 13 m (70% of total number of piles) Line B-C/5: 16 m (30% of total) QC methods MDM Core drilling Wet grab sampling of fresh piles Extraction of complete piles (pull out with Gewe rod) Environmental control methods Settlement gauges Movement sensors on surrounding properties Gamletull, MDM-pålar 22