Experimental Study of a Single Story-Single Bay
Steel Moment Frame Subjected to Dynamic Loading
Kayo TANIGUCHI
Candidate for the Degree of Master of Engineering
Supervisor: Dr. Taichiro Okazaki
Division of Architectural and Structural Designtests. A catching frame was placed beneath the moment frame
to prevent damage to the shake table. Doubler plates werewelded to the panel zones to avoid yielding of the column
panels. Therefore, the expected energy dissipation
mechanism was yielding at the top of the columns. Length
was scaled to 1/3, but time was not scaled. The fundamentalvibration period of the specimen was computed as 0.24 s.
Large beams were fastened to the specimen above which steel
plates were attached to supply mass. The total weight of themass added to the specimen was 5750 kg.

Introduction
The 1994 Northridge earthquake and 1995 Kobe earthquake
reminded engineers that severe damage and potential collapseof steel buildings can happen. Seismic design provisions
ensure ductile performance of steel moment resisting frames
by adequate connection details and a strong column-weakbeam proportion rule.
Major experiments are required to examine the damage
process under exceedingly large ground motions leading tocomplete failure, or collapse, of building systems, and thereby
to determine the safety margin against collapse. Suchexperiments, or shake table tests, require careful planning.
Shimada. et al. [1] conducted a reduced scale shake-table testin preparation for a full-scale moment frame test at E-Defense
in order to examine instrumentation schemes and thepredictability of response. Kaneshiro. et al. [2] conducted a
1/3-scale shake-table test on a one bay-two story steel
moment frame, with intentional damage introduced in thebeam-to-column connections, to observe how fracture ordamage of one beam end propagates to the entire structuralsystem.
This paper reports a 1/3-scale shake-table test of a one
bay-one story moment frame at the National ResearchInstitute for Earth Science and Disaster Prevention (NIED) in
Tsukuba in 2020 as a preliminary test of the main specimen(4 stories – 2 bays specimen conducted in 2021). The
objective of the test was to verify that reduced-scale specimen,with simplistic details, behave similarly to real building
systems and to validate the experimental method can be used
for main test. A specific interest was to examine how theinertia force, produced by a large mass out of dimensional
proportion, may be transferred to the specimen.

Excitation
As listed in Table 2, the JMA Kobe NS motion recorded fromthe 1995 Kobe earthquake was repeated 9 times withamplitudes 10, 25, 50 and 100%. Figure 3 shows the target
100% motion in form of spectral acceleration (SA) versus
spectral displacement (SD) relationship. The computed
fundamental vibration period and computed plastic strength,
Steel Mass1200– e mp t m sse m
1.

mn
1Pin

1

se e mMoving Direction

Test Plan

Fig. 1. Test specimen

Specimen

Table 1. Material properties by coupon testLocation

MaterialColumn
BeamSS400

σy[N/mm2]319
349

σu[N/mm2]447
471

JIS M16 turn buckle

e p te(b)1000

As shown in Figure 1, the specimen had a planof 1.5×2 m and height of 1.2 m. The columns
were H-100×100×6×8 and the beams were H150×75×5.5×7, both of SS400 steel. Thecolumns were pinned at the shake table througha foundation beam. Table 1 lists the mechanicalproperties established based on tension coupon

iti n p teing m ss1000

inst(a)600

800

Fig. 2. Specimen details: (a)Turn buckle brace, (b) Beam-tocolumn connection

e . Excit ti n P n

1234
5678
910%
25%50%10%100%10%100%100%10%

Expected
Behavior
Elastic
Elastic
Elastic
Elastic
Plastic
Plastic
Plastic
Plastic
Plastic40

T=0.24[s] T

3500

. s

35

400
325

Scale30e m St inge

Beam Rotation

2520

1510mnSt in

T=1.0[s]5Endplate
Displacementge

000.1

0.2

0.3

0.4

0.5

0.6

SD (m)

3Test

400300S msTi nt
isp cementFig. 3. S – S c ve

Fig. 4 Instrumentation plan

based on measured yield strength values, are indicated in thefigure. The 10% motion was sufficiently small to keep thespecimen elastic and was thereby used to compute thefundamental vibration period before and after the primary
motions. The 50% motion was expected to subject thespecimen near the proportional limit. The 100% motion wasrepeated three times. Under the 100% motion, the specimen
was expected to yield but was not expected to develop
substantial plastic deformation.

4.2

1 .

-17.5
1 .

1 .

-17.7

9.8

4.2(c) 14
9.8

14+(a)
1000-- 9.8(d)10005.9300(b)

700

700300(e)Fig. 5 Initial condition and assumptions before excitation:(a) Measured axial force of column, (b) Assumed mass
distribution, (c) Assumed concentrate load, (d) Assumed
shear force diagram

Initial Condition
Change in force distribution was measured in the column
during the process of tightening the column endplates andplacing the masses. Figure 5 shows the assumed axial force,shear force and bending moment diagrams in the system.
Figure 6 shows the initial axial force after fastening all masses.
Gravity load distributed evenly, and according to tributaryarea, to all columns. Because strain measurement was taken
only at the columns, the force distribution in the beams
needed to be estimated by mechanics.

7.21

5.9
0.66

.

1.33.

F me

F me

- 0.14.

Fig. 6 Initial bending moment diagram combine
assumption with measured axial force: (a) Frame AB, (b)Frame CDAcceleration[ m/s/s ]Test result
As shown in Figure 7 for Test 5 (the first 100% motion),
the acceleration record produced by the shake table closely
matched the target motion. At the estimated fundamental
period of the specimen, the produced motion was 5% greaterthan target.
Figure 8 shows the change in fundamental vibration
period from the 10% motions (Tests 1, 4, 6, 9) using the zerocrossing method from response acceleration of the mass. The
period elongated slightly from 0.263 s at the beginning to0.275 s after the three 100% motions.
Figure 9 shows the story shear versus drift angle
relationship from Test 3 (50% motion) and Test 5 (first 100%motion). The plastic strength of the system, based on
measured yield strength, is shown in the figure. Test 3

1 .

-18.3

Instrumentation
Figure 4 shows instrumentation plan that involved 96
channels. Three dimensional accelerometers were placed on
the middle of the mass and on the shake table. Story drift
angle was measured in each plane by wire transducers and by
subtracting slipping of endplate. Rotation of the beam end andshear deformation of the panel zone were measured bytransducers. Restoring forces were measured by elastic strain
gauges attached to the flanges of each column and beam atlocations expected to remain elastic.

1 .

9.8

mping

np t
T get
Natural period

Fig. 7 Record of absolute
acceleration response

100 %excitation

Fig. 8 The change infundamental vibration period
responsepQp

p-Qp-Mp
p

(a)

(b)

Fig. 9 Shear force and story drift angle relationship: (a) test 3,(b) test 5.
A : Acceleration
Mnod(a)(b)
Fig. 10 Time history of nod moment: (a)Column (b) Beam.

joint, as shown in Figure 13 (b). The
vertical force taken equal to the axial
force in the column below. Figure14
QBshows the bending moment diagrampsampled at the instant when the story
A : Acceleration
shear was measured. Complete bending
Mpin
Q = QA + QB
moment distribution may be derived for+ QC + QD
clear segments with two instrumented
sections, namely the column and middle
segment of the beam. The bendingp
moment distribution in the outer
segments of the beam was produced
based on measurement at one section(a)(b)and assuming that the shear force
Fig. 12 Verification of forces: (a) Shear force by column shear and condensation
equaled the shear force in the middle
models, (b) Relationship of column top moment and pin moment
portion of the beam plus the initial shear
shown in Figure 6 (d). The jump in value
produced a maximum story drift of 0.01 rad and the specimen
at the boundaries may be attributed to the concentrated
remained elastic. Test 5 produced a maximum story drift of moments shown in Figure 14. The initial bending moment as0.263 rad and a residual deformation of 0.01 rad.
shown in Figure 6 (d) was deducted from transferred force
Figure 10 shows the time history response of the column
because they were not generated by excitation. Figure 15
end moment and beam end moment from Test 5. The plastic
checked the inertia force and transferred force to the beam
moment of the members, based on measured yield strength,from 12 s to 15 s. The plots extracted the step when Figure 14
are shown in the figure. As expected, the column exceeded
was shown. Transferred force had terrible noise, so it was
the plastic moment, while the beam remained elastic.
filtered using moving average of 5 points.
The moments find in two different ways in the plot
Discussion
mentioned above were also evaluated by yielding moment ofbeams. Transferred force was 18.7 kNm and the inertial force
Verification of measurement
was 42.7kN. The error 24.0 kNm divided by yielding moment
32kN is equal to 75.2 % where the resolution of the beam
Figure 12 (a) compares the story shear force obtained formoment derived from strain gauge was 0.18 kNm. Moreover,
Test 5 (100% motion) by two methods: from strain
the positive and negative peaks were also evaluated. Positive
measurement and equilibrium conditions, and from inertia, orand negative peak differed 16.8 kNm and 14.3 kNm
multiple of mass and acceleration. The latter assumes thatrespectively. The error was evaluated in the same way andviscous damping is null. Story shear obtained from the twopercentage was 52.5 % and 44.3 %. The transferred force wasmethods were almost identical. As shown in Figure 12 (b), thesmaller than the inertia force, but they have similar behaviors.
strain gauge measurement was also used to confirm thatbending moment at the pin support was in fact very near zero.
Equivalent SDOF model
QC

Verification of torsion of mass
Fig. 2 indicates that the inertia force was transferred to thespecimen through horizontal braces, placed in the same
horizontal plane as the top flange of beams, and transverse
floor beams. The line of action of the inertia force wassubstantially higher than the centerline of the beams.
Therefore, an attempt was made to back calculate the force
transferred to the beam. The transferred forces weresimplified as a set of concentrated horizontal load, verticalload, and moment acting at each beam/column-to-floor beam

A single-degree-of-freedom model with bilinear properties
was subjected to the recorded table motion. The model wasprovided with the aforementioned theoretical stiffness andplastic strength, and a secondary-to-post-yield stiffness ratio of1/10000. The damping ratio was 1.5 %. Figure 16 compares thedisplacement response from shake-table test and model.
Equivalent SDOF managed to capture the experiment with acertain degree of accuracy. However, the residual displacementof the SDOF was -5.0mm and of the experiment was -9.2mm.
The model was undetermined by 54.3%.

B/2NAND1e

3M4

Transmitted forcee(NA+NB +NC +ND)×2/B+M1+M2+M3+M4+M5+M6+M7+M8

Ma×e

(a)

Fig. 13 Expected moment by ground motion: (a) Inertial force (b) Transferred force
Sec nemReliable Shear force

13.9

10.9
1.

-14.2.

Q.

3 .1
33.0

ei ement

MFig. 14 Calculation method of torsional moment of secondary beam
ModelecFig. 15 Expected axial force byground motion

specimen. Seismic performance and theexperimental method were summarized
below:▪
The acceleration record produced by theshake table closely matched the target motion.
▪
As expected from material test, column
reached Mp. On the other hand, beam remainedelastic.
▪
Strain measurement was suitable.
▪
The bending moment at the pin support
was in fact very near zero. The performance
was required for the main frame.
▪
From initial strain of the column, weightof mass was distributed almost even to all thecolumns before excitation.
▪
Since the mass was tightened rigidly tothe beam, the inertial force was transferred tothe at each beam/column-to-floor beam joint.
The inertia force, produced by a large mass outof dimensional proportion, matched thetransferred force to a certain extent.
▪
The numerical simulation of theequivalent SDOF system, using a bilinear stressstrain relationship, fairly agreed with theexperimental response.
The main test (4 stories – 2 bays specimen)
was conducted in 2021 following theexperimental method and the measurement
was succeeded.

QpReferences
ModelRecordFig. 16 Result of elastic – plastic analysis of single degree of freedom: (a)Displacement response, (b) Shear force and story drift angle relationship

Conclusions
A 1/3-scale, single story-single bay specimen was tested on a
shake table as a preliminary test of the four stories-four bays

-Qp

[1] Yuko Shimada, Motoki akazawa et al.
Shaking table test on collapse behavior of smallscale steel frame structure. J. struct. Constr. Eng.,AIJ, No.620, 125-132, Oct., 2007
[2] Yusuke KANESHIRO and Takashi
HASEGAWA and satoru HIROSHIMA. Shakingtable test on seismic response of steel 2-story frame
structure considering fracture at beam – end. AIJ J.
Technol. Des. Vol. 26, No.62, 147-152, Feb.
2020