Laboratory of Engineering for Maintenance SystemGraduate School of Engineering Hokkaido University

2

Date Study Date Study Date Study

2010/8/23Departure 2010/9/20Listening Speech 2010/10/18Preparing – S3-G-SR instrumentation

2010/8/24Greeting to all lab member 2010/9/21Design of experimental program 2010/10/19Preparing – S3-G-SR instrumentation

2010/8/25Paper work 2010/9/22Design of experimental program 2010/10/20Material prop test

2010/8/26Surface preparation for RC cap 2010/9/23Design of experimental program 2010/10/21Test – S3-G-SR, Material prop test

2010/8/27Design of experimental program 2010/9/24Meeting with fyfo company 2010/10/22Preparing test for S4-P-SR

2010/8/30Anchorage design 2010/9/27Design of experimental program 2010/10/25Preparing test for S4-P-SR

Meeting

2010/8/31Anchorage design 2010/9/28Design of experimental program2010/10/26

Preparing test for S4-P-SR

2010/9/1Material prop test design 2010/9/29Apply PET primer2010/10/27TEST S4-P-SR

Preparing material prop test

2010/9/2Material prop test design 2010/9/30Apply PET putty & GFRP epoxy

2010/9/3Design of experimental program 2010/10/1Design of experimental program

2010/9/6Design of experimental program 2010/10/4Testing frame set uo

2010/9/7Design of experimental program 2010/10/5Set up C1 and set up string pots

2010/9/8Build masonry wall 2010/10/6Wire of string pots attached

2010/9/9Build masonry wall 2010/10/7Material prop test

2010/9/10Open bank account „& Social security

number2010/10/8Preparing – Cl instrumentation

2010/9/13Design of experimental program 2010/10/11Preparing – Cl instrumentation

2010/9/14Design of experimental program 2010/10/12Preparing – Cl

2010/9/15Meeting , Material prop test design 2010/10/13Test CL specimen

2010/9/16Design of experimental program 2010/10/14Preparing – S3-G-SR

2010/9/17Visit bank & Social Security office 2010/10/15Attend Master‟s defense, Preparing –

S3-G-SR

Conduct experimental program using full-scale wall specimens

Examine various anchorage systems

Simulate the simple boundary conditions and loading experienced by existing structures

Evaluate the effectiveness of a GFRP system to strengthen infill masonry walls

Twenty full-scale specimens

Two main FRP materials, anchorage systems

Experimental Testing of Full-Scale Wall Panels

The main objective of the proposed research program is to investigate the most

effective FRP anchorage system for strengthening masonry infill structures.

The study includes two types of FRP:

Glass Fiber Reinforced Polymer (GFRP) and Polyethylene Terephthalate (PET).

Each type of FRP system will be evaluated using five different types of anchorage.

Specimen ID FRP Type Anchorage Type

C1 ----- -----

S1-G-O GFRPOverlap

S2-P-O PET

S3-G-SR GFRPShear Restraint

S4-P-SR PET

S5-G-FB GFRPFiber Bolt

S6-P-FB PET

S7-G-EB GFRPEmbedded Bar

S8-P-EB PET

S9-G-SK GFRPCFRP Shear Key

S10-P-SK PET

S11-C-NSM CFRP Near Surface Mounted

The main objective of the proposed

research program is to investigate the

most effective FRP anchorage system

for strengthening masonry infill

structures.

The research includes an experimental

program consisting of a total of 12

infill wall specimens, including 11

strengthened wall panels and one

unstrengthened (control) wall.

Table 1: Proposed test specimens

The test specimens are designed to determine the most effective anchorage system for FRP strengthening of

infill masonry walls. The specimens were strengthened with a different type of externally bonded FRP sheet.

Front view

5’

7’-6’’

1’

1’

6’’1’4’

1’-

6’’

3’

6 ½’’

3 5/8’’

Profile view

7’-6’’

5’

Glass Fiber Reinforced Polymer (GFRP) was supplied by Fyfe Co. LLC

Polyethylene terephthalate (PET) was supplied by Maeda Kosen Co. Ltd.

Figure 1: Details of test specimen

Overlap Embedded FRP bar Shear Restraint Anchorage

CFRP Shear key NSM FRP barFiber Bolts

GFRP GFRPGFRP

GFRPGFRP

PET PETPET

PETPET

The test specimens were loaded out-of-plane with a uniformly distributed pressure to simulate the differential pressure

induced by a tornado. The airbag was placed within a steel frame between the brick walls and the laboratory reaction

wall. In addition to the four reaction rods, the RC cap is given greater rigidity using four steel bolts centered on the

specimen. These bolts are secured only to the steel frame.

Figure 2: Details of test set up

RTR

MTR

MBR

RBR

MBL

RBL

RTL

MTL

PTI

PTQ

PTM

PBQ

PBI

RT

M

MBI

MTI

MT

Q

MID

MBQ

RBI

RTI

RB

M

String potentiometers were used to measure the

deflection at various locations on the test specimens.

Measuring strain in the FRP sheets aids in

understanding the extent to which the FRP is being

utilized in resisting the load.

Figure 3-1: Location of string potentiometers Figure 3-2: Location of strain gages

Fixed Frame used for Instruments

String potentiometers were used at the locations shown to measure the out-of-plane displacement profile of the wall

and the frame.

Taking midspan as an example, as the walls deflect, the potentiometers measure the lateral displacement, allowing for

the determination, in this case, of the out-of-plane displacement profile at midspan.

Figure 4: String potentiometers set up

OTR

OBR

OTL

OBL

VTRVTL

Vertical ties Reaction rods

Load cells were attached with the reaction rods to determine the load in the reaction rods.

The measured load in the reaction rods provides an indication of how the load is distributed

throughout the section.

Figure 5: Location of load cells

Applying Primer for PET sheet

Applying Putty for PET sheet

RC cap with HSS (test frame) Build masonry infill Conducted by local mason

Masonry wall

Impregnating FRP with EpoxyMixing thickened epoxyEmbedding fiber bolts

Placing FRP sheets

Making SR anchorage

Fiber bolts anchorage

Attaching string potsPlacing SR anchorage

String pots to the back poles

Before the tests After the test (Cl)Transfer the next specimen

Once all instrumentation was attached, specimens were subjected to cycles of uniformly distributed

pressure according to the loading protocol shown. The pressure was increased in increments by

inflating the airbag. The load was held at each increment for 5 mins after which, the specimens were

unloaded to the service load of 1.2 psi before proceeding to the next increment.

0

1

2

3

4

5

6

7

8

9

10

11

0 20 40 60 80 100 120 140

Time (min)

Pre

ssu

re (

psi

)At each loading step, the

pressure load level will be

maintained constant for 5

minutes per ASTM E 72.

Figure 6: Typical loading sequences

A comparison between the total applied load and the total load measured by the reaction rods is given in below

figure.

The total measured load was not linearly related to the total applied load.

The 60-80% difference between the total applied load and the total measured load is likely due to frictional forces.

Figure 7-1: Load Comparison for CL

Friction parts

The specimen is put on this steel stand and friction is caused between the bottom of RC and

this steel stand.

Roller system might solve this problem “How do we reduce this frictional force?”

Figure 7-2: location of frictional forces

Revised

Low friction - Roller system -

Figure 7-4: close up view of roller system

The regions where the frictional force was

caused were substituted for the roller system.

The frictional forces can be extremely reduced

by this system. The closed up view of roller

system are shown in Fig 7-4.

The self-weight of the wall creates a friction

force along the bottom edge of the wall

panel that is not present along the top edge.

Figure 8-1: Load Comparison for S3-G-SR

After the above mentioned revise, the total applied load and

the total load measured by the reaction rods were compared

again.

The problem by the frictional force was mostly solved.

However, total measured load has exceeded total applied

pressure which should be an upper limit of line.

Uniform pressure was applied to the

masonry via an airbag. During

testing, the airbag was in full contact

with the surface of the masonry.

However, as deformation of masonry

wall progresses, a range which are

applied pressure might extend to RC

cap that is shown in Fig 8-2.

It should be one reason of excess of

upper limit of total applied load.

Figure 8-2: extension of applied

pressure zone

18

CL S1-G-O

S2-P-O S3-G-SR

The envelope of the pressure-deflection curves is

shown in Figure. 9. S3-G-SR recorded ultimate

pressure about 8 times larger than control specimen.

In the just overlap system, S1-G-O had the larger

ultimate pressure, while S2-P-O had more ductility.

Figure 9: Load-deflection behavior

8x

Figure 10: Out-of-plane displacement profiles

along vertical line

The measured out-of-plane displacement profiles for

applied pressures of Cl-2.24 psi, S1-5.25 psi, S2-

4.25 psi, and S3-16.26 psi are shown in Figure 10.

In this figure, a solid line connects the measured

values.

Figure 11: FRP strain profiles along vertical line

The measured strains in the FRP sheets at various locations are shown in Figure11. The strain profiles of the FRP

sheet along a vertical line at mid-width at various applied pressures are shown in Figure 3-2. In the specimens

S1-G-O and S2-P-O, the profiles clearly show that debonding initiated at the top interface between the PET

and the RC cap in the anchorage zone, with very large strains developing in the FRP in this region, but very

little strain developing just below the interface on the masonry itself. On the other hand, there are no observed

strain in the anchorage zone in S3-G-SR.

Date

From 10/27/2010 Strengthen & Anchorage – S6-P-FB

To 11/23/2010 Strengthen & Anchorage – S7-G-EB

Strengthen & Anchorage – S8-P-EB

Strengthen & Anchorage – S9-G-SK

Strengthen & Anchorage – S10-P-SK

Strengthen & Anchorage – S11-C-NSM

Test - S5-G-FB

Test - S6-P-FB

Test - S7-G-EB

Test - S8-P-EB

Test - S9-G-SK

Test - S10-P-SK

Test - S11-C-NSM

25days until the return day…….