1.Test Setup and Instrumentation

visitormaddeningUrban and Civil

Nov 25, 2013 (3 years and 9 months ago)

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1.

Test Setup and Instrumentation

The overview of the test setup is shown in
Figure
1
-
1
. The central portion of the 30
-
foot long pipe was
supported by a central concrete pedestal. The two ends of the pipes were restrained to the West and East
shake table respectively with steel
restraints. The ends of the pipes were sealed and closed with two
mechanical end caps, and subsequently the pipes were pressurized with water pressure of approximately
48 psi before the tests and monitored between tests to ensure consistent pressure in eac
h test.

The detailed
dimensions of the test setup are shown in
Figure
1
-
2
.


Figure
1
-
1

Overview of Shake Table Test Setup


East Shake Table

Mounting Plate

Steel Restraint

Post
-
Tension
Steel Rods

West Shake Table

Central
Concrete
Pedestal

Steel Plank

Digital Camera


East Joint

West Join
t

Ductile Iron Pipe


Figure
1
-
2

Dimensions of Test Setup


In order to measure and record the data from the experiments, the pipe specimens and the shake tables
were instrumented with potentiometers, accelerometers and strain gaug
es. The Krypton K600 Optical
Measurement System was also used in the tests to verify the accuracy of the test results. The general
instrumentation lists and drawings are provided in Appendix A. The number of sensors varied according
to the requirements of
the different tests.

1.1

Pipe Specimens and Insituform IMain liner

Four DI pipes with 6 in. nominal diameter, and 30 ft. nominal length were tested on the two shake tables
in
the Structural Engineering and Earthquake Simulation Laboratory (SEESL) at UB
. Each p
ipe specimen
had two push
-
on joints located at its 1/3 span. The standard DI pipes used in the tests were provided by
the Los Angeles Department of Water & Power (LADWP) and sent to InsituForm Technologies
(Chesterfield, MO) to be lined with Insituform IMa
in Liner technology and cut to a prescribed length, as
shown in
Figure
1
-
3
. The composition of the Liner was IMain epoxy resin with IMain

hardener. Six pipe
specimens were delivered to UB for the shake table tests. Pipe specimens SP1 to SP 4 were used for the
first set of tests and the last two specimens were saved for future testing.


Figure
1
-
3

Pipe Specimen Layout (Insituform Technologies, 2011)

Before the IMain Liner was applied, the wall of the pipe consisted of two layers
--

ductile iron layer and
interior mortar liner. The ductile iron layer has a nominal wall thickness of 0.30 in. and

the interior mortar
liner has a nominal thickness of 0.15 in. The outside diameters of the unlined pipes were approximately
6.90 in.
Figure
1
-
4

shows the detailed co
nfiguration of the ductile iron joint with Insituform IMain liner.
When the IMain liner was applied to the pipes, it went across the joints of the DI pipes continuously
without any trenches. The curing process of the IMain Liner formed a bond between the
outer surface of
the IMain liner and the inner surface of the mortar. This liner reduces the inner diameter of the original DI
pipes to approximately 5.50 in.


Figure
1
-
4

Cross Section of DI Joint with IMain

Liner

Figure
1
-
5

shows a close
-
up view of a typical joint equipped with various sensors before a test. Four
potentiometers and six LED sensors were placed around the joints to measure the joint opening and
b
ending in both principal directions of the pipe.


Figure
1
-
5

Close
-
up View of Instrumented Joint

The material properties of the DI pipes and Insituform IMain liner used in the tests are listed in
Table
1
-
1

and
Table
1
-
2
, respectively.


Table
1
-
1

Mechanical Properties of Ductile Iron (Flowserve Corporation, 1999)

Material Name

Ductile Iron

Modulus of Elasticity (ksi)

24000

Yield Strength (ksi)

42

Tensile Strength (ksi)

70

Poisson’s Ratio

0.275

Elongation (%)

30


Table
1
-
2

Mechanical Properties of Insituform IMain Liner (Zhong, et al. 2011)

Longitudinal Direction

Circumferential Direction

Shear Properties

Longitudinal Modulus, E
2

(psi)

481000

Circumferential Modulus, E
1

(psi)

707000

In
-
plain Shear
Modulus, G
12

(psi)

221800

Longitudinal Tensile
Strength, F
2t

(psi)

6100

Circumferential Tensile
Strength, F
1t

(psi)

11200

Shear Strength, F
s

(psi)

5530

Ultimate Longitudinal
Tensile Strain,

2t

(%)

2.31

Ultimate Circumferential
T
ensile Strain,

1t

(%)

2.62

Ultimate
Longitudinal Shear
Strain,

s

(%)

4.02

Longitudinal
Compressive Modulus,
E
2c

(psi)

481000

Circumferential
Compressive Modulus, E
1c

(psi)

663000



Longitudinal
Compressive Strength,
F
2c

(psi)

11300

Circumferential
Compressive Strength, F
1c

(psi)

14500



Ultimate Longitudinal
Compressive Strain,

2c

(%)

2.74

Ultimate Circumferential
Compressive Strain,

1c

(%)

2.17



Minor in
-
plane Poisson’s
Ratio, v
21

0.35

Major in
-
plane Poisson’s
Ratio, v
12

0.53





1.2

Major
Components for the Test Setup

1.2.1

Twin Re
-
locatable Shake Tables

Both static and dynamic tests were performed on the twin re
-
locatable SEESL shake tables at UB. The
pipe specimens were spanned across both shake tables and were restrained in all directions on b
oth shake
tables. Both shake tables have six degrees of freedom. In this first set of tests, the two shake tables were
excited only in the longitudinal direction of the pipe specimen (or X axis of the two shake tables) to
simulate the major transient groun
d deformations caused by the seismic wave propagation during an
earthquake event. The pipe specimens were approximately 30 feet long and a separation between the two
tables of 19 feet was chosen for the tests. The pertinent specifications of the shake tabl
es are shown in
Table
1
-
3
.

Table
1
-
3

Shake Table Specifications

Table size with extension platform in p
lace (feet)

23 × 23

Maximum specimen mass (ton)

20 nominal / 50 maximum

Frequency of operation (Hertz)

0.1~50 nominal / 100 maximum

Nominal Performance

X axis, Y axis and Z axis

Stroke (in.)

± 6, ± 6 and ± 3

Velocity (feet/sec.)

4.1, 4.1 and 1.6

Acceleration (g)

±1.15 , ±1.15 and ±1.15 (with 20 ton specimen)

Maximum Dynamic Lateral Force (kips)

93

Maximum Dynamic Vertical Force (kips)

220


Based on material tests performed on the Insituform IMain liner, the tensile capacity of the liner in the

DI
pipe ranges from 32 kips to 35 kips, which exceeds the shear capacity of the load cells available in
SEESL. Therefore, the forces on the pipe specimens were obtained through the differential pressure cells
of the shake table actuators.

1.2.2

Steel Restraint
s

In order to connect the pipe specimens to the two shake tables and central concrete pedestal, six steel
restraints with post
-
tension rods were designed and fabricated, as shown in
Figure
1
-
6
.


Figure
1
-
6

Overview of Two Steel Restraints for Shake Table Tests

Each steel restraint was designed based on the capacity of the pipe and Insitu IMain

liner. For this
purpose, it was assumed that the DI pipe yielded in flexure in both horizontal and vertical directions, and
the joints reached its failure capacity in tension during the tests. Because the axial
-
pull tests on the pipe
without Insituform IM
ain liner performed at Cornell University (Cornell University NEESR Group,
2011a) showed that the strengths of the push
-
on joints were much smaller than the tensile capacity of the
Insituform IMain liner, the resistance of the push
-
on joints in the pipe sp
ecimen was neglected in
calculating the tensile capacity of the joints. Moreover, considering the load capacities of the two shake
tables, as shown in
Table
1
-
3
, the
input motions used in the tests only consisted of positive longitudinal
displacements to ensure that the pipe would be mainly subjected to tensile forces and avoid metal butting
in the joints during the tests. Therefore, the shear forces and bending moment
s were resisted directly by
the steel restraints, while the tensile forces and possible compressive forces caused by the residual
deformations of the liner were resisted by the friction between the inner surfaces of the restraints and the
outer surface of
the DI pipe specimens.

Each steel restraint consists of two mirror
-
imaged components: the bottom and top assemblies. Except for
four extra holes on the bottom plate used for fixing the restraints the two assemblies were identical.
Figure
1
-
7

shows a 3
-
D view of the bottom assembly of the steel restraint. The steel saddles of the
restraints were fabricated to perfectly match the outside diameters of the DI pipe specime
ns to maximize
the contact area. Also, the inner surfaces of the saddles were sand
-
blasted to increase the friction
coefficient and to avoid slippage of the pipe specimens during the tests. Ten post
-
tension rods of grade B7
and 5/8 in. diameter were used i
n each restraint to clamp the pipe specimens. The shop drawings and
construction details for the steel restraints are provided in Appendix B.


Figure
1
-
7

Bottom Assembly of the Steel Restraint

1.2.3

Central
Concrete Pedestal and Steel Plank

A central concrete pedestal with the dimensions of 48 in.
×
24 in.
× 40 in.

was cast to attach two steel
restraints and support the pipe specimen at its mid
-
span. Concrete with a compressive strength of 5000 psi
and grade
60 reinforcements were used for the concrete pedestal.

A 1
-
in. thick steel plate was embedded on top of the concrete block to attach the two steel restraints, as
shown in
Figure
1
-
8
. The same hole
-
patterns as the bottom plate of the steel restraints were drilled in the
steel plate for connecting the restraints. In order to minimize sliding and rotation of the central pedestal,
four post
-
tensioned steel rods of 1
-
1/4 i
n. diameters were used to connect the central concrete pedestal to
a steel plank that spanned across the shake table trench. The shop drawings and construction details for
the central concrete pedestal are provided in Appendix C.


Figure
1
-
8

Central Concrete Pedestal for Shake Table Tests

The steel plank consisted of four stitch
-
welded I
-
beams with a cross section W18
×
106. Four post
-
tensioned DYWIDAG bars were used to connect the steel plank with the trench f
loor to prevent sliding
and overturning of the plank during tests.
Figure
1
-
9

shows a 3
-
D view of the test setup with all the major
components.


Figure
1
-
9

Overview of Complete Shake Table Test Setup

The concrete pedestal was designed to be fully fixed in all directions at the center span of the pipe.
However, a small amount of rotation of the central pedestal was detecte
d during the shake table tests, as
discussed later.




2.

Appendices

2.1

Appendix A

General Instrumentation Lists and Drawings

This appendix contains the typical instrumentation from the dual shake table tests. The instrumentation
was modified slightly according

different test set up.

Table
2
-
1

Instrumentation List

Instrumentation (Pacific System)

Quantity

String Potentiometer (SP)

19

Potentiometer (D)

20

Accelerometer (A)

19

Strain Gauge (SG)

48

Total:

116


Instrumentation (Krypton System)

Quantity

Digital Camera

6

Krypton

1






Check List of the Instrumentations

Nomenclatures:

X
---
Longitudinal


Y
---
Transverse


Z
---
Vertical

Joint 1
---

West Joint

Joint 2
---

East Joint

Table 1
---

West Table

Table 2
---

East Table

MP
---

Steel Mounting Plates


Pacific System

String Potentiometers


Name

Location

Orientation

Description

SP1

Table 1

X

Abs. Disp. Of T1

SP2

Table 1

X

Abs. Disp. Of T1

SP3

Pipe1

Longitudinal

Abs. Disp. Of Pipe1

SP4

Pipe1

Longitudinal

Abs. Disp. Of Pipe1

SP5

Pipe2_West

Longitudinal

Abs. Disp. Of Pipe2

SP6

Pipe2_West

Longitudinal

Abs. Disp. Of Pipe2

SP7

Mid Support

Longitudinal

Abs. Disp. Of Mid Support

SP8

Mid Support

Longitudinal

Abs. Disp. Of Mid Support

SP9

Pipe2_East

Longitudinal

Abs. Disp. Of Pipe2

SP10

Pipe2_East

Longitudinal

Abs. Disp. Of Pipe2

SP11

Pipe 3

Longitudinal

Abs. Disp. Of Pipe3

SP12

Pipe 3

Longitudinal

Abs. Disp. Of Pipe3

SP13

Table 2

X

Abs. Disp. Of T2

SP14

Table 2

X

Abs. Disp. Of T2

SP15

Steel
Girder

X

Abs. Disp. Of Steel Girder

SP16

Steel Girder

X

Abs. Disp. Of Steel Girder

SP17

Steel Girder

Y

Abs. Disp. Of Steel Girder

SP18

Mid Support

Y

Abs. Disp. of Mid Support

SP19

Mid Support

Y

Abs. Disp. of Mid Support

















Potentiometers



Name

Location

Orientation

Description

D1

Table 1

X

Rel. Disp. Between T1 & MP

D2

Table 1

X

Rel. Disp. Between MP & Restraint on T1

D3

Table 1

X

Rel. Disp. Between Restraint & Pipe on T1

D4

Joint 1

Longitudinal

Rel. Disp. Between Bell
& Spigot of Joint 1

D5

Joint 1

Longitudinal

Rel. Disp. Between Bell & Spigot of Joint 2

D6

Joint 1

Longitudinal

Rel. Disp. Between Bell & Spigot of Joint 3

D7

Joint 1

Longitudinal

Rel. Disp. Between Bell & Spigot of Joint 1

D8

Center Support

Longitudinal

Rel. Disp. Between Steel Girder & Mid Support

D9

Center Support

Longitudinal

Rel. Disp. Between Mid Support & Restraint

D10

Center Support

Longitudinal

Rel. Disp. Between Restraint & Pipe at Mid Support

D11

Center Support

Longitudinal

Rel.
Disp. Between Steel Girder & Mid Support

D12

Center Support

Longitudinal

Rel. Disp. Between Mid Support & Restraint

D13

Center Support

Longitudinal

Rel. Disp. Between Restraint & Pipe at Mid Support

D14

Joint 2

Longitudinal

Rel. Disp. Between Bell &
Spigot of Joint 2

D15

Joint 2

Longitudinal

Rel. Disp. Between Bell & Spigot of Joint 2

D16

Joint 2

Longitudinal

Rel. Disp. Between Bell & Spigot of Joint 2

D17

Joint 2

Longitudinal

Rel. Disp. Between Bell & Spigot of Joint 2

D18

Table 2

X

Rel. Disp.
Between T2 & MP

D19

Table 2

X

Rel. Disp. Between MP & Restraint on T2

D20

Table 2

X

Rel. Disp. Between Restraint & Pipe on T2






Accelerometers



Name

Location

Orientation

Description

A1

Table 1

Longitudinal

Lon. Acc. Of Shake Table 1

A2

Table 1

Longitudinal

Lon. Acc. Of Shake Table 1

A3

Joint 1

Longitudinal

Lon. Strain of Pipe 1 near Joint1 on Spigot

A4

Joint 1

Transverse

Tran. Strain of Pipe 1 near Joint1 on Spigot

A5

Joint 1

Vertical

Ver. Strain of Pipe 1 near Joint1 on Spigot

A6

Joint 1

Longitudinal

Lon. Strain of Pipe 1 near Joint1 on Bell

A7

Joint 1

Transverse

Tran. Strain of Pipe 1 near Joint1 on Bell

A8

Joint 1

Vertical

Ver. Strain of Pipe 1 near Joint1 on Bell

A9

Mid Support

Longitudinal

Lon. Strain of Mid Support

A10

Mid Support

Transverse

Tran. Strain of Mid Support

A11

Mid Support

Vertical

Ver. Strain of Mid Support

A12

Joint 2

Longitudinal

Lon. Strain of Pipe 1 near Joint1 on Spigot

A13

Joint 2

Transverse

Tran. Strain of Pipe 1 near Joint1 on Spigot

A14

Joint 2

Vertical

Ver. Strain of Pipe 1 near Joint1 on Spigot

A15

Joint 2

Longitudinal

Lon. Strain of Pipe 1 near Joint1 on Bell

A16

Joint 2

Transverse

Tran. Strain of Pipe 1 near Joint1 on Bell

A17

Joint 2

Vertical

Ver. Strain of Pipe 1 near Joint1 on Bell

A18

Table 1

Longitudinal

Lon. Acc. Of Shake Table 2

A19

Table 1

Longitudinal

Lon. Acc. Of Shake Table 2





Strain Gauges


Name

Location

Orientation

SG1

Side

Longitudinal

SG2

Side

Longitudinal

SG3

Top

Longitudinal

SG4

Bottom

Longitudinal

SG5

Side

Longitudinal

SG6

Side

Longitudinal

SG7

Top

Longitudinal

SG8

Bottom

Longitudinal

SG9

Side

Longitudinal

SG10

Side

Longitudinal

SG11

Top

Longitudinal

SG12

Bottom

Longitudinal

SG13

Side

Longitudinal

SG14

Side

Longitudinal

SG15

Top

Longitudinal

SG16

Bottom

Longitudinal

SG17

Side

Longitudinal

SG18

Side

Longitudinal

SG19

Top

Longitudinal

SG20

Bottom

Longitudinal

SG21

Side

Longitudinal

SG22

Side

Longitudinal

SG23

Top

Longitudinal

SG24

Bottom

Longitudinal

SG25

Side

Longitudinal

SG26

Side

Longitudinal

SG27

Top

Longitudinal

SG28

Bottom

Longitudinal

SG29

Side

Longitudinal

SG30

Side

Longitudinal

SG31

Top

Longitudinal

SG32

Bottom

Longitudinal

SG33

Side

Longitudinal

SG34

Side

Longitudinal

SG35

Top

Longitudinal

SG36

Bottom

Longitudinal

SG37

Side

Longitudinal

SG38

Side

Longitudinal

SG39

Top

Longitudinal

SG40

Bottom

Longitudinal

SG41

Side

Longitudinal

SG42

Side

Longitudinal

SG43

Top

Longitudinal

SG44

Bottom

Longitudinal

SG45

Side

Longitudinal

SG46

Side

Longitudinal

SG47

Top

Longitudinal

SG48

Bottom

Longitudinal





Krypton System

Cameras



Name

Location

Orientation

Krypton

Joint 1

Y

Camera 1

Joint 1

Y

Camera 2

Joint 1

Z

Camera 3

Joint 2

Y

Camera 4

Joint 2

Z

Camera 5

Global

45 deg.

Camera 6

Global

45 deg.






2.2

Appendix B

Shop
Drawings and Construction Details of Steel Restraints










2.3

Appendix C

Shop Drawings and Construction Details of Concrete Pedestal