PROJECT: PROPOSED DEVELOPMENT OF 242 UNITS OF 27 STOREYS CONDOMINIUM (PHASE 1A-RC3) AT SOUTHERN PRECINCT ON LOT 6 TO LOT 16 AND PT9315, MUKIM PETALING, DAERAH PETALING, SELANGOR DARUL EHSAN FOR SUNWAY SOUTH QUAY SDN. BHD. MICROPILE DESIGN Working Load
140
tonnes
Section Properties: Dia. of drilled hole
300
mm
Concrete grade, f cu
30
N/mm2
API pipe outer dia API pipe thk.
177 11.5
mm mm
Steel yield strength, f y Elastic Modulus of Steel, E s
525 200
N/mm2 kN/mm2
*
Elastic Modulus of Concrete, E c *default value
25
kN/mm2
*
Tabulations of Areas:
Area of drilled hole Area of steel pile Area of cement grout
70686 5979.25 64706.75
mm2 mm2 mm2
1) STRUCTURAL DESIGN
i) Consider USED API PIPIE only Ultimate Capacity
=
fyAs 313.91
tonnes
ii) Design as short column From Equation 38 BS8110 : Clause 3.8.4.3: Ulti Ultim mate ate Cap Capacit acity y
=
0.35f .35fcu cuAc Ac +0.6 +0.67 7fyA fyAs 278.26 tonnes
From the values tabulated in (i) and (ii), the lower value is taken into consideration Ultimate Capacity Factor of safety provided
= =
279 1.99
tonnes
2) Geotechnical Design Design is based on SOCKETING INTO LIMESTONE fs- fcu/20 or lower depending on soil Assumed bond stress of grout/limestone, fs Minimum socketing length required
= =
950 3.91
kN/mm2 m
3) Elastic Shortening Check: Equivalent Young's Modulus, Eeq
= =
(EsAs+EcAc)/At 39.80 kN/mm2
Elastic Shortening of micropile P/kN 1400 L/m 2 Elastic shortening/mm 1.00 L= length of pile, P=Applied load
= 1400 4 1.99
PL/AtEeq
1400 6 2.99
1400 8 3.98
kN/mm2 (worst case condition)
0.00
4) Buckling Capacity of Micropile i) Using Mascadi's Formula Assume Soil Elasticity Mod, Esl Bd
= =
0.001 0.85
Buckling Capacity, Qk
=
2√(Esl.EI)
Moment inertia of pipe, Is
=
π(Do4-Di4)/64
=
20570489.2
Momnet inertia of grout, Ig
=
Total moment of inertia, It
mm4
π(Dh4-(Do4-Di4))/64
=
377038260.8
=
Is+(Ec/Es)Ig
mm4
=
67700271.8
=
(0.2EcIc+EsIs)/(1+Bd)
=
3.24E+09
Buckling Capacity, Qk
=
3601.59
Factor of safety provided
=
2.57
EI
mm4
kN
ii) Using Euler Formula Buckling Capacity, Qk
=
π2EsIt/Le2
Effective Length, Le
=
π2EsIt/√(FOS*WL)
=
6.18
m
5) Pile Head Design Ref. BS8110:Part 1: 1985 Section 5 CI 5.2.3.4 - Design Ultimate Bearing Stress
For contact face of a steel bearing plate caset into member of supper and not exceeding 40% of the concrete dimension: 0.8 fcu Strength of Concrete (Pile Cap)
=
30
N/mm2
Ref: BS5950: Part 1 Design by the effective area method using reference 27.1 steel design manual Area required teq
= = = = >
87500 11.5 87500 78.40 (D-2t)/2
mm2 mm mm2
D+2K Adopt
= = =
87500 333.78 340
mm2 mm mm
Pyp Tp
= =
265 41.89
N/mm2 mm
(refer to Table 6, BS5950)
Shear Check
=
25.90 OK
mm
<
Tension Load
=
28
Steel Area Required
=
1049.48
(2K+teq)(D-teq)π
K K if K>D/2, then
(D+2K)2π/4
=
77
41.89
U-Bar for Pile Head 1. say 20% working load is tension tonnes mm2
(defaulted to high yield bar fy=460)
N/mm2 mm nos. mm
(each bar)
2. Anchorage Bond Length Equation 49, BS8110: Part 1: 1985 fb B
= =
fb Bar Size Adopted Number of Bars L
= = = =
B√fcu 0.5 2.74 12 3 678.01
Design of Fillet Weld Weld Size
=
E-43 Electrode Strength of fillet welds Required Weld Length Maximum available weld length
= = = =
6*
mm
0.92 kN/mm tension load/ weld strength 456.52 mm 556.06 mm
(perimeter of steel pipe)
PROJECT: PROPOSED DEVELOPMENT OF 242 UNITS OF 27 STOREYS CONDOMINIUM (PHASE 1A-RC3) AT SOUTHERN PRECINCT ON LOT 6 TO LOT 16 AND PT9 315, MUKIM PETALING, DAERAH PETALING, SELANGOR DARUL EHSAN FOR SUNWAY SOUTH QUAY SDN. BHD. MICROPILE DESIGN Working Load, WL =
140
tonnes
Section Properties: Dia. of drilled hole =
300
mm
Concrete grade, fcu =
30
N/mm2
API pipe outer dia =
177
mm
Steel yield strength, fy =
525
N/mm2
API pipe thk. =
11.5
mm
Elastic Modulus of Steel, Es =
200
kN/mm
Elastic Modulus of Concrete, Ec = *default value
2
kN/mm
25
Tabulations of Areas: 2
70686
mm
Area of steel pile, A s =
5979.25
mm
Area of cement grout, A c =
64706.75
mm
Area of drilled hole, A t =
2 2
1) STRUCTURAL DESIGN
Cross Section of Micropile
i) Consider USED API PIPIE only Ultimate Capacity
=
fyA s 313.91
tonnes
ii) Design as short column From Equation 38 BS8110 : Clause 3.8.4.3: Ultimate Capacity
=
0.35fcu Ac + 0.67f yAs 278.26 tonnes
From the values tabulated in (i) and (ii), th e lower value is taken into consideration Ultimate Capacity Factor of safety provided,
= =
278.26 1.99
tonnes
2) GEOTECHNICAL DESIGN
Design is based on SOCKETING INTO LIMESTONE fs- fcu/20 or lower depending on soil Assumed bond stress between grout & limestone, fs Minimum socketing length required, L
= =
950 3.91
=
(EsAs+EcAc)/At
=
39.80
2
kN/mm m
3) ELASTIC SHORTENING CHECK
Equivalent Young's Modulus, Eeq
2
2
kN/mm
* *
Elastic shortening of micropile
=
PL/AtEeq
P (kN) 1400 1400 1400 1400 L (m) 2 4 6 8 Elastic shortening (mm) 1.00 1.99 2.99 3.98 Notes: a) L= length of pile, P=Applied load b) Elastic shortening should be within 25mm for maximum length of micropile 4) BUCKLING CAPACITY OF MICROPILE i) Using Mascadi's Formula
Assume:
Soil Elasticity Mod, Esl Beta Value, bd
= =
0.001 0.85
Buckling Capacity, Qk
=
2√(Esl.EI)
Moment inertia of pipe, Is
=
π(Do4-Di4)/64
=
20570489.2
Momnet inertia of grout, Ig
=
Total moment of inertia, It
kN/mm2 (worst case condition)
mm4
π(Dh4-(Do4-Di4))/64
=
377038260.8
=
Is+(Ec/Es)Ig
mm4
=
67700271.8
=
(0.2EcIc+EsIs)/(1+Bd)
=
3.24E+09
Buckling Capacity, Qk
=
3601.59
Factor of safety provided
=
2.57
EI
mm4
kN
ii) Using Euler Formula Buckling Capacity, Qk
=
π2EsIt/Le2
Effective Length, Le
=
π2EsIt/√(FOS*WL)
=
6.18
m
FOS = 2.5
5) PILE HEAD DESIGN Ref. BS8110:Part 1: 1985 Section 5 CI 5.2.3.4 - Design Ultimate Bearing Stress
For contact face of a steel bearing plate cast into member of support and not exceeding 40% of th e concrete dimension: 0.8 f cu Strength of Concrete (Pile Cap)
=
30
2
N/mm
Ref: BS5950: Part 1 Design by the effective area method using reference 27.1 steel design manual Area required teq
2
= =
87500 11.5
mm mm
= = >
87500 78.40 (D-2t)/2
mm
D+2K Adopt
= = =
87500 333.78 340
mm2 mm mm
Pyp Tp
= =
265 41.89
N/mm2 mm
(refer to Table 6, BS5950)
Shear Check
=
25.90 OK
mm
<
Tension Load
=
28
Steel Area Required
=
1049.48
(2K+teq)(D-teq)π
K K if K>D/2, then
(D+2K)2π/4
2
=
77
41.89
U-Bar for Pile Head
1. say 20% working load is tension tonnes 2
mm
(defaulted to high yield bar fy=460)
2. Anchorage Bond Length Equation 49, BS8110: Part 1: 1985 fb B
= =
fb Bar Size Adopted Number of Bars L
= = = =
B√fcu 0.5 2.74 12 3 678.01
2
N/mm mm nos. mm
(each bar)
Design of Fillet Weld Weld Size
=
E-43 Electrode Strength of fillet welds Required Weld Length Maximum available weld length
= = = =
6*
mm
0.92 kN/mm tension load/ weld strength 456.52 mm 556.06 mm
(perimeter of steel pipe)
