penstock embedded design
TRANSCRIPT
WASKITA - GXED/TKL CONSORTIUM
Document No.
Penstock Design
Rev.: 0
HPP-GYM-DC-ENG-ED-xxx
Page Number
Page 1 of 6
CLIENT : PT. PLN (Persero)
PROJECT NAME : GENYEM HYDRO POWER PROJECT (2x10MW)
PROJECT TITLE : HPP
LOCATION : GENYEM, PAPUA
PLN DOCUMENT NO : 2168-GY02-S-07-DC-DSGN-002
REV DATE DESCRIPTION PREP’D CHK’D APP’D
WASKITA - GXED/TKL CONSORTIUM
Document No.
Penstock Design
Rev.: 0
HPP-GYM-DC-ENG-ED-xxx
Page Number
Page 2 of 6
Table of Contents
TABLE OF CONTENTS.................................................................................................................................... 2
1 PENSTOCK DATA.................................................................................................................................. 3
1.1 LONGITUDINAL STRESSES............................................................................................................................31.2 Buckling check......................................................................................................................................4
WASKITA - GXED/TKL CONSORTIUM
Document No.
Penstock Design
Rev.: 0
HPP-GYM-DC-ENG-ED-xxx
Page Number
Page 3 of 6
1 EMBEDDED PENSTOCK
1.1 LONGITUDINAL STRESSES
The main longitudinal stresses for embedded penstock at Between Surge Tank and Bend
3 are as follow :
Longitudinal Stress at Point Before Power House Inlet
1. Poisson’s effect stress
Where:
= Stress due to Poisson’s effect (kgf/cm2)
ν = Poisson’s effect ratio of steel (0.3)
= Circumferential stress (kgf/cm2)
Poisson's effectν = 0.30
Location bend 1 - bend 2 bend 2 - bend 3section 1 2σh (kg/m²) 9,365,073.53 13,220,168.07
σt3 (kg/m²) 2,809,522.06 3,966,050.42
2. Temperature stress
Where:
= Stress due to temperature change (kgf/cm2)
α = Coefficient of linear expansion (1.2 x 10-5 /°C)
E = Elastic Modulus of steel (2.1 x 106 kgf/cm2)
ΔT = Temperature change (20°C)
Temperature stress :α = 1.20E-05 /°C
WASKITA - GXED/TKL CONSORTIUM
Document No.
Penstock Design
Rev.: 0
HPP-GYM-DC-ENG-ED-xxx
Page Number
Page 4 of 6
E = 2.10E+06 kg/cm²ΔT = 20 °C
σt2 = 504.00 kg/cm²
σt2 = 5,040,000.00 kg/m²
1.2 BUCKLING CHECK
For buried pipe, Section 1 (between bend 1 and bend 2)
Stress due to external pressure and critical buckling pressure is calculated using E.
Amstutz formula
Where
σF = Yield point of material, 5,079.90 kg/cm2
σN = Circumferential direct stress at deformed pipe shell, iterated
t = Penstock thickness, 1.0 cm
rm = Penstock radius to center of shell, 113.1 cm
ko =gap between concrete and external surface of pipe, 0 by means of
grouting
WASKITA - GXED/TKL CONSORTIUM
Document No.
Penstock Design
Rev.: 0
HPP-GYM-DC-ENG-ED-xxx
Page Number
Page 5 of 6
With σN calculated, pk can be determined by following equation:
Soil density, γ =1,800 kg/m3
Depth of embedded penstock is designed to be not more than 4 meters
Then
Overburden stress at top of penstock = γ x H = 7,200 kg/m2 lower than the allowable
buckling pressure, pall ( kg/cm2)
WASKITA - GXED/TKL CONSORTIUM
Document No.
Penstock Design
Rev.: 0
HPP-GYM-DC-ENG-ED-xxx
Page Number
Page 6 of 6
Table 1. Embeded pipe buckling check
Location bend 1 - bend 2 bend 2 - bend 3section 1 2t (cm) 1.00 1.00D (cm) 225.00 225.00rm (cm) 113.1 113.1rm/t 113.1 113.1Es* 2.31E+06 2.31E+06σN (kg/m2) 13,516,146.97 13,516,146.97
σN (kg/cm2) 1,351.61 1,351.61μ 1.406 1.406σf* (kg/cm2) 5,079.90 5,079.90left side 0.558 0.558right side 0.558 0.558
1.63E-05 1.63E-05Pk (kg/cm2) 11.23 11.23
Pall (kg/cm2) 7.49 7.49
Pall (kg/m2) 74,881.84 74,881.84
hmax (m) 41.60 41.60