strain monitorinng case study: sutonng cable-stayed bridge...ble-stayed b e study is a s [1-2]....
TRANSCRIPT
![Page 1: Strain monitorinng case study: Sutonng Cable-stayed Bridge...ble-stayed B e study is a s [1-2]. easured Dat ridge (SCB) longest cable f this bridge onal artery w Suzhou by cr portant](https://reader034.vdocuments.us/reader034/viewer/2022042102/5e7e8316da500650c1637679/html5/thumbnails/1.jpg)
Co
1
2
3 Departm
ABSTRAreliabilityChina, i.edata. The in the prev
Test Stru
Sutong Cof 1,088 China. Ge1. It is acities of NRiver andmain framprovince vehicles pbridge is meteorolobeen insta
Orthotropa lightweihigh longemployedSCB. Unloads, theof OSD wcombinatiplane andstresses, catastroph(RSG are traffic andalong thecorresponperformanselected in
Among aYB201, Yselected toinduced st
ollection of SH
Strain
Key Laborato
Key Laborato
ment of Civil, E
ACT: This cay assessments e., Sutong Capresented casvious papers
ucture and M
able-stayed Bm, is the
eneral view ocritical nati
Nantong and d plays an immework of thof China. N
pass through tlocated at t
ogical disastealled on this b
pic steel deckight deck systgitudinal stiffd in the main nder long-terme welded conwill be subjecion of local
d out-of-planeleading to lo
hic failure ofinstalled at dd wind loads
e main girdernding strain vnce of the wen this study.
ll fifty-six stYB205, YB21o analyze the tress cycles. T
HM Case Stud
monitorin
Hao
ry of C&PC St
ry of C&PC St
Environmental,
ase study sumof key welde
able-stayed Bse study is a s[1-2].
Measured Dat
Bridge (SCB)longest cable
of this bridge onal artery wSuzhou by cr
mportant role he highway n
Numerous freithe bridge dathe mouth ors like typho
bridge for long
k (OSD), tem with
ffness, is girder of m traffic nnections cted to a lized in-bending
oad-induced f bridge strucdifferent sectios as an impor of SCB, thvalues are larlded details o
train gauges i12, YB220, aglobal mecha
The layout of
dies by ASCE
Up
3.50.5
ng case stu
o Wang1, Jian
tructures of Miwanghao
tructures of Mijx199
Architectural
mmarizes theed details of oridge, based summary of a
ta
), with a maine-stayed bridis shown in
which connecrossing the Y
in constitutinetwork in Jight and pas
aily. In additioof the Yangtzons happen fg-term perfor
fatigue cracctures. Thereons of the brirtant part of
he mid-span rger than thoof the OSD, o
installed at thand YB222) lanical responf the strain sen
E EMI Structur
Figure 2. Se
pstream strain g
3.75 3.75 3
T03
T12
K
udy: Suton
nxiao Mao2
inistry of [email protected] of [email protected], U
variation feat
orthotropic steon the one-y
authors’ previ
n span dge in Figure cts the
Yangtze ng the
Jiangsu senger on, the ze River in frequently. Thrmance assess
cking. The gfore, the spoidge girder tothe SHM sysection carri
ose at other sonly the strain
he mid-span located at the
nses of OSD, insors at the m
ral Health M
Figure 1. Sut
ensor layout at
gauge
YB222
3.75 fast l1.75
Temperature meter
ng Cable-s
and Jian Li3
cation, Southeadu.cn cation, Southean Univ. of Kansa
tures of the seel deck of thyear continuoious studies; d
the eastern herefore, a cosment.
growth of crot-welded eleo monitor the ystem. Amonies the largessections. The
n gauges insta
section of SCe U ribs alonincluding the
mid-span secti
Monitoring & C
ong Cable-stay
mid-span secti
Downstr
lanemiddle
lane slow
T06
T15
stayed Bri
3
ast Univ., Nanj
ast Univ., Nanj
as, Lawrence, U
strain responshe longest cabous structural detailed inform
coastal areaomprehensive
racks can poctrical resistastructural res
ng different sst bending merefore, to evalled at the m
CB, six straing the longitue slow-varyingion of SCB ar
Control Comm
yed Bridge
ion
eam
YB220
lane emergencylane
idge
ing, China,
ing, China,
USA, jianli@ku
ses and the fable-stayed brid
health monitmation is ava
a of China, we SHM system
otentially resuance strain gsponses inducections distri
moment, hencvaluate the fa
mid-span sectio
n gauges (YBudinal directiog trend and vere shown in F
mittee
u.edu
fatigue dge in toring
ailable
where m has
ult in gauges ced by ibuted ce the fatigue on are
B120, on are ehicle Figure
![Page 2: Strain monitorinng case study: Sutonng Cable-stayed Bridge...ble-stayed B e study is a s [1-2]. easured Dat ridge (SCB) longest cable f this bridge onal artery w Suzhou by cr portant](https://reader034.vdocuments.us/reader034/viewer/2022042102/5e7e8316da500650c1637679/html5/thumbnails/2.jpg)
Collection of SHM Case Studies by ASCE EMI Structural Health Monitoring & Control Committee
2. The strain gauge is 60 mm long and is protected by the stainless-steel cover. The sampling frequency of the strain gauges is 10 Hz. Four strain gauges (YB120, YB201, YB205, and YB212) are installed at the top flange of OSD, while the other two (YB220, and YB222) installed at the bottom flange. In addition, four temperature sensors (T03, T06, T12, and T15) are used to assess the correlation between strain varying trend and temperature change. Furthermore, four strain gauges around the U rib K, as shown in Figure 3, are utilized to conduct fatigue reliability assessment of the welded details. The sensors YB203, YB205, and YB206 are strain gauges measuring longitudinal strain responses, while YB204 measures the transverse ones.
The measured 24-hour strain responses of YB205 on Jan. 7, 2009 are shown in Figure 4(a). The strain responses are composed of two components, namely, the slow-varying component and the dynamic component. The slow-varying trends are extracted using MAM and results show that it has the similar variation trend with the structural temperature. After the slow-varying trends of the strain responses are removed using MAM, the remaining components, namely as the dynamic strain responses, can be used to represent the dynamic loading effects of traffic and wind. The dynamic strain responses of YB205 on August 10th are displayed in Figure 4(b), which contain higher-frequency signals with the maximum amplitude close to 350με.
(a) (b) Figure 4. Recorded 24-h strain responses of YB205. (a) Original signal;(b) Dynamic component.
SHM Methodology and Results
The slow-varying trend of strain responses is firstly eliminated with the combination of moving average method and padding scheme, and the dynamic strain responses are obtained. After that, the dynamic strain responses are transformed into stress values according to the Hooke’s law with the modulus of 210,000 MPa. The stress-range histograms of the selected strain gauges, i.e., YB120, YB201, YB205, YB212, YB220, and YB222, are obtained using the rainflow cycle counting algorithm which includes four steps, i.e., hysteresis filtering, peak-valley filtering, discretization, and four-point cycle counting. On that basis, the lognormal probability distribution function (PDF) is applied to fit the distribution of the estimated stress
0 4 8 12 16 20 24Time / h
-100
0
100
200
300
400Original ValueVariation trend
0 4 8 12 16 20 24
10
15
20
25
30
35
40
45Mean Temperature
0 4 8 12 16 20 24Time / h
-100
-50
0
50
100
150
200
250
300
350
Figure 3. Strain gauges around U rib K
U rib
deck YB203
YB204
YB205
YB206
perpendicular
parallel
asphalt concrete pavement
Figure 5. Fitted stress range PDFs
![Page 3: Strain monitorinng case study: Sutonng Cable-stayed Bridge...ble-stayed B e study is a s [1-2]. easured Dat ridge (SCB) longest cable f this bridge onal artery w Suzhou by cr portant](https://reader034.vdocuments.us/reader034/viewer/2022042102/5e7e8316da500650c1637679/html5/thumbnails/3.jpg)
Collection of SHM Case Studies by ASCE EMI Structural Health Monitoring & Control Committee
(a) (b)
ranges PDFs are shown in Figure 5. Afterwards, the equivalent stress ranges Sre of the selected strain gauges are calculated according to the equations listed in [1]. Based on the continuously monitored strain responses by the SHM system, the daily equivalent stress ranges and stress cycles during 2009 were calculated and shown in Figure 6.
Figure 6. Calculated daily: (a) equivalent stress range; and (b) number of cycles in 2009
The lifetime fatigue reliability of three welded details of orthotropic steel deck will be investigated, including rib-to-deck at diaphragm (RTDD), rib-to-diaphragm (RTD), and diaphragm-to-deck (DTD) details. The fatigue crack of RTDD would be evaluated with YB204. The fatigue crack of RTD will be evaluated with YB205 and YB206. The fatigue crack of DTD will be evaluated with YB203. Following the limited state function of Miner’s damage accumulation index, the fatigue reliability of three welded details are estimated using the field-monitoring stress ranges and cycles. The estimated time-dependent fatigue reliability indexes are shown in Figure 7.
Lessons Learned
This case study demonstrated the feasibility of performing detailed evaluation of fatigue reliability of the welded details with field-monitored strain responses. The presented results can provide valuable references for the fatigue-resistance design, construction, operation, and maintenance of long-span bridges and add to our knowledge about the operational conditions of these bridges in terms of serviceability, strength, and reliability.
Acknowledgements
The authors would like to gratefully acknowledge the support from the National Natural Science Foundation of China (Grant No. 51722804). The support from the Jiangsu Health Monitoring Data Center for Long-span Bridges is also acknowledged.
References
[1] Jianxiao Mao, Hao Wang, Jian Li. Fatigue reliability assessment of a long-span cable-stayed bridge based on one-year monitoring strain data, Journal of Bridge Engineering, 2018: 24(1), 05018015.
[2] Hao Wang, Tianyou Tao, Aiqun Li, Yufeng Zhang. Structural health monitoring system for Sutong cable-stayed bridge, Smart Structures and Systems, 2016, 18(2): 317-334.
0 73 146 219 292 365Day
0
5
10
15
20
25YB203YB204
YB205YB206
Num
ber
of C
ycle
s
Figure 7. Fatigue reliability indexes of welded details
Fat
igue
rel
iabi
lity
inde
x