final report on field testing and analysis of bridge ...€¦ · three crc deck-girder approach...

FINAL REPORT ON

FIELD TESTING AND ANALYSIS

OF BRIDGE 01496A

FOR YAMHILL COUNTY

Christopher Higgins, PhD

Mary Ann Triska

October 20, 2010

2

Bridge Description

Lambert Slough Bridge #01496A crosses Lambert Slough in Yamhill County, OR, and is

the only bridge to provide access to and from Grand Island, OR. The bridge combines

prestressed concrete girders, conventionally reinforced concrete deck-girders (RCDG), and

conventionally reinforced concrete (CRC) box girders. The drawings for the bridge are

dated 1963. There are eight spans: two prestressed girder approach spans (span lengths =

70 ft) on the west side, three CRC box girder main spans (span lengths=90, 120, 90 ft), and

three CRC deck-girder approach spans on the east side (span lengths = 64 ft). The spans

support a roadway width of 24 ft. There are 5 girder lines in the prestressed spans, four

web stems in the box girder spans, and 4 girder lines in the RCDG spans. The RCDG

girders are 14.5 in. x 54 in., uniform and prismatic except from the diaphragms to the

continuous support locations (bents 7 and 8) where the web width increases in a linear

taper. Diaphragms are located at the 1/3 points along the RCDG spans. The box girder

webs are 10 in. x 78 in., uniform and prismatic except where they increase in width at the

continuous support locations. Internal diaphragms are located at the quarter points in the

boxes along the spans. The reinforced concrete deck is 6.5 in. thick over the RCDG and

box girder spans and an asphalt wearing surface is applied to the bridge. The specified

concrete compression strength was 3300 psi and the reinforcing steel was specified as

ASTM A305 intermediate grade (nominally 40 ksi yield stress) deformed round bars.

Crack Identification and Mapping

Visual inspection of the downstream face of the exterior girders was performed to identify

cracks and select instrument locations. Flexural and diagonal cracks were observed to

correspond to those previously reported and marked on the girder surface (Burgess and

Niple 2004). No visible cracking was observed on the exterior face of the prestressed

concrete girders. The prestressed girder spans could not be completely inspected due to

growth of vegetation and access limitations near the western side of the bridge. As would

be expected, diagonal cracks were concentrated near support locations and vertically

oriented cracks were closer to midspan locations. The crack sizes, orientations, density and

3

locations correspond to similar aged bridges inspected by the investigators on other Oregon

highways and interstates.

Instrumentation of Bridge

After inspection, locations were selected for instrumentation. At selected crack locations,

strain gages and displacement transducers were installed. Crack locations were selected

based on the width and orientation of the cracks and to coincide as best as possible with

locations that were of similar distance from the face of the support. These criteria

facilitated subsequent load distribution estimates. Strain gages were installed to measure

the reinforcing steel stress at the crack locations. Strain gages were installed by chipping

into the concrete and exposing the embedded reinforcing steel at the crack locations. The

actual amount of concrete removed varied based on the concrete cover, but typical concrete

removal provided an exposed reinforcing length of approximately 3 to 4 in. overall,

centered about the crack, as illustrated in Fig. 1. The width of the excavation was

approximately 2 to 3 in. permitting preparation of the rebar surface for bonding strain

gages. The deformation pattern on the reinforcing steel was not removed to install the

strain gages, as the strain gage size (Measurements Group strain gage EA-06-062AQ-350,

with a gage length of 1/16 in. and gage factor of 2.105) permitted installation within the

deformation pattern. This strain gage was a bondable type gage with a 350 Ohm resistance.

A typical installation of a strain gage and position sensor is also shown in Fig. 1. Strain

gages applied to the reinforcing steel were installed in 7 different locations on the bridge.

Both flexural bars and stirrups were instrumented. A single surface concrete strain gage

was applied near a vertically oriented crack tip near the deck soffit as seen in Fig. 2. This

crack is the same one that crosses the two other strain gages which were applied to the

flexural reinforcing steel in the box girder. The instrumented locations are illustrated

schematically in Fig. 3. As seen here, only the downstream exterior girders/web and the

downstream interior girder/web were instrumented. Symmetry of structural responses was

assumed and test trucks were positioned as described subsequently to enable prediction of

load distribution. Displacement sensors were mounted across the cracks to monitor crack

motions. These were applied relatively close to the location of the strain gages as seen in

Fig. 1.

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The strain gages and displacement sensors were connected to a Campbell Scientific

CR9000 data logger. This is a high-speed, multi-channel, 16-bit digital data acquisition

system. Resolution for the strain measurements was greater than 5.84E-7 strain and for

displacements was 0.0001 inch. In order to reduce noise and prevent aliasing in the data,

both analog and digital filters were employed. During the ambient monitoring period, data

were sampled at 100 Hz. During controlled truck tests, data were sampled at 200 hz. The

system recorded sensor readings and converted signals into corresponding strains and crack

displacements. Data from sensors were archived for retrieval and post-processing.

Testing Methods

Two different types of live load data were collected: response under ambient traffic loading

and response under controlled truck loading. The strains and crack displacements generated

by normal traffic flow were recorded over a period of 9.57 nonconsecutive calendar days

from August 25 to September 24, 2010. The system also recorded individual event

histories when strain thresholds exceeded 50 microstrain ( at sensor location CH_8. For

each trigger event, data were recorded for several seconds prior to and following the

trigger. The four largest events recorded during the ambient traffic monitoring period are

shown in Fig. 4a, b, c and d.

Controlled truck loading tests were conducted using a heavily loaded Yamhill County

maintenance truck and trailer, as shown in Fig. 5a. The axle weights and spacing are shown

in Fig. 5b. Traffic was temporarily halted using a flagging crew so that the control truck

would be the only vehicle on the bridge during data collection. The control truck passed

over the bridge at several designated speeds and lane positions. Test speeds varied from

slow (approximately 5 mph), to fast (in the range of 30 to 40 mph). Lane locations

included placing the truck in the lane, straddling the truck over the center-line stripe, and

placing the truck in the opposite lane going the wrong direction. Lane positions and the

corresponding truck positions relative to the girder/box stem locations are illustrated in Fig.

6. During each pass of the control truck, reinforcing steel strains and crack motions were

recorded for each of the instrumented locations. Peak strain values for each of the test runs

are summarized in Tables 1a and 1b for the eastbound and westbound passes, respectively.

5

Strain ranges measured for each of the test runs are summarized in Tables 2a and 2b for the

eastbound and westbound passes, respectively. The measured time-history response data

for all instruments and loading positions and speeds for the test truck with trailer are shown

in Appendix A.

Ambient Traffic Induced Reinforcing Steel Stress

Ambient traffic-induced strains at each of the instrumented crack locations were monitored

at each bridge for a period of 9.57 days. The strain-ranges and numbers of cycles recorded

at the instrumented locations are shown in Fig. 7. The largest single strain-range measured

was approximately 135 microstrain (corresponding to 4.3 ksi) at location CH_8 (a flexural

reinforcing bar on the interior girder of the RCDG). The largest strain range measured on a

box girder was also 135 microstrain (corresponding to 4.3 ksi) at location CH_4 (a stirrup

on the box girder). The measured strain ranges were converted to stress ranges using the

modulus of elasticity of steel (29,000 ksi) and concrete (~3,625 ksi). Then, using Miner’s

Rule (Miner, 1945), the variable amplitude stresses were described as an equivalent

constant amplitude stress-range for each of the instrumented locations:

3 3 itot

ieqv SR

N

nSR [1]

where SRi is the ith stress-range, ni is the number of cycles observed for the ith stress-range,

and Ntot is the total number of cycles at all stress ranges. The equivalent constant amplitude

stress-ranges were below 1.0 ksi at all locations, as seen in Table 3. These relatively small

equivalent constant amplitude stress ranges are small compared to those measured in

previous research on other 1950’s vintage RCDG bridges (Higgins et al. 2004) and

indicate high-cycle fatigue of the embedded reinforcing steel is unlikely.

6

Field Measured Dynamic Influence/Impact

As vehicles move across the bridge at highway speeds, the static force effects may be

amplified due to the dynamic response of the structure under the moving load and/or due to

impact of the wheels on the deck surface due to uneven approaches or deck surface

imperfections. An impact/dynamic coefficient was determined using the control test truck

data at each of the reinforcing steel strain locations. Impact coefficients were calculated as

the ratio of the peak strain produced by the truck as it moves in the marked lane at traveling

speed over the peak strain when the truck moves in the marked lane slowly (5 mph) across

the bridge. Impact coefficients were determined only for the cases when the truck was over

the instrumented section of the bridge (westbound inlane and eastbound in the wrong lane).

The impact coefficients are reported in Table 4. As seen in Table 4, there were cases when

the dynamic effects reduce the stress amplitude (ratios less than 1.0). The largest

controlling impact coefficient for the box girder was 1.12 (shear) and in the RCDG was

also 1.12 (flexure). These are less than that recommended by the AASHTO LRFR

provisions (typically taken as 1.2).

Field Measured Load Distribution

Distribution of shear and moment across the multiple girders/boxes on each of the bridges

was inferred from the relative magnitude of the peak measured strains in each girder across

the instrumented section of the bridge. Distribution of shear and moment was determined

from maximum measured strains for the truck passages at a slow speed (5 mph) in each of

the lane positions. Distribution factors were determined for a single truck in the various

lane positions and for two trucks in adjacent lane positions by superposition of the single

lane cases. The strain at a given section of the bridge was divided by the sum of the strains

on all girders at the section to determine the distribution factor. Theoretical 2-lane

positioning was also investigated by mirroring results from the single-lane test results.

Distribution factors based on strain measurements for the bridge are shown in Table 5. The

worst case load distribution factors for shear in the RCDG were approximately 0.42 for

one-lane loaded and 0.54 for two-lanes loaded (this is found by taking twice the value

shown in the table for the two lane loaded case to account for analysis and design practice

7

that uses a single lane loading to compute load effects in the bridge members). Shear

distribution in the box girder could not be determined as only the exterior stem was

available for instrumentation. The worst case load distribution factors for moment in the

RCDG were approximately 0.43 for one-lane loaded and 0.52 for two-lanes loaded. The

worst case load distribution factors for moment in the box girders were approximately 0.32

for one-lane loaded and 0.56 for two-lanes loaded. The distribution factors calculated here

represent the proportion of the statical force effect (shear or moment) on the bridge

assigned to an individual girder/box at the section under consideration when either one or

two trucks are in possible lane positions. The measured distributions are lower than would

be expected from the AASHTO design provisions (better load distribution than assumed at

design).

LRFR Rating and Risk Index Factors

The instrumented sections of the bridge were evaluated per AASHTO-LRFR and using the

OSU risk index methodology (Higgins et al. 2004). Ratings and risk indices were

computed for the 105.5 kip test truck configuration used for field testing (Fig. 5b). This

truck is believed to be consistent with the expected operational conditions on the bridge in

the future. The analysis methodology is described below.

Distribution factors for shear and moment were based on the field measured values. Two

lane distribution factors were used as these are the maximums in Table 5 (must take twice

the value shown in the table for the two lane loaded case). The maximum field measured

impact factors of 1.12 were applied to both shear and flexural load effects (from Table 4).

The resistance of these sections was computed per AASHTO-LRFD section 5.8 which uses

modified compression field theory (MCFT). The sectional capacity depends on a number

of variables including the concrete and rebar material strength (both transverse and

longitudinal steel), stirrup spacing, amount of flexural steel (including partially developed

bars), and the flexural resultant moment arm. The design drawings show class “A” 3300

psi concrete compressive strength and ASTM A305 “Intermediate Grade” deformed

reinforcing bars that correspond to 40 ksi yield. Because some cracks are diagonal, the

available longitudinal rebar areas crossing the diagonal crack is located at the beam soffit

8

for the locations considered. Further, the statical shear and moment at the section are

computed at vertical cuts taken at mid-length of the diagonal cracks. The diagonal crack is

idealized as originating at the flexural tension steel (near bottom of the web) and is

assumed to be 45o for the purpose of determining the available steel areas and the location

for performing statics. The RCDG span was evaluated at two sections corresponding to the

instrumented sections: 31 ft and 7.4 ft east of Bent 6. The box girder span was evaluated at

two sections corresponding to the instrumented sections: 33 ft and 7.1 ft west of Bent 6.

The box girder section was treated as an equivalent deck-girder considering the outside

stem with only 1/6 of the available flexural steel in the lower flange attributed to this

section. In all cases the skin steel was neglected. AASHTO-LRFD MCFT curves were

developed at each of the instrumented sections. The resistance factor used with the shear-

moment interaction capacity curve was 0.9 for subsequent LRFR checks.

The flexural steel plays a key role in the shear-moment interaction capacity of the section,

and, where available, partially developed flexural steel was used. The amount of partially

developed steel was determined by taking the ratio of the available rebar embedded length

at the intersecting plane of the crack (considering the controlling lengths available on each

side of the crack) to the AASHTO-LRFD computed development length (straight bar

development per 5.11.2.1). Once the available flexural steel was determined, the effective

flange width was computed per AASHTO-LRFD 4.6.2.6. These were then used to compute

the AASHTO-LRFD MCFT nominal capacity envelopes per 5.8.3.3.

Load and Impact Factors

Dead load on the bridge was computed by estimating the total weight of the bridge and

distributing the weight evenly to all four girders as a uniformly distributed load. The

computed service-level weight of components (DC) was 1.66 kips/ft for the RCDG and

2.13 kips/ft for the box girder. A 2 in. thick asphalt wearing surface (DW) was assumed for

the bridge and this weight was also assumed to be evenly distributed to all four girders as

0.11 kips/ft. The dead load factors used in the rating analyses was 1.25 for DC and 1.5 for

DW. The dead load factor (applied to DC and DW) used in the risk index calculation is

1.0.

9

Analyses were performed using the test truck configuration illustrated in Fig. 5b. Oregon

specific live load factors (Groff, 2006) were used to compute AASHTO-LRFR consistent

rating factors. The Oregon-specific live load factor for the 105.5 kip GVW truck was used

with the value of 1.25 for ADTT<500.

Risk indices were computed using unfactored live and dead loads and an AASHTO-MCFT

nominal moment-shear interaction bias factor of 1.1 and a coefficient of variation of 7.4%,

based on full-scale test results designed to reflect 1950’s vintage detailed reinforced

concrete girders (Higgins et al. 2004).

Rating Factor and Risk Index Results

At each of the sections identified, the available capacity was compared with the demands

to determine the LRFR ratings and OSU risk indices for each of the 4 instrumented

sections. Results are shown in Figs. 8 to 11. As seen here, the instrumented sections rate

well according to the LRFR method and have low risk indices. These indicate the sections

are sufficient to safely carry the loads represented by the test truck. The box girder near

midspan shows the least conservative outcomes, although the analysis made conservative

assumptions that it operates as an individual girder rather than a box section (and used only

the exterior stem in the analysis).

Discussion

Based on the largest measured ambient traffic-induced responses (Fig. 4a, b, c, and d) and

the test truck measured responses (Appendix A and Table 1a and 1b) on the instrumented

sections of the bridge, it appears that the bridge is currently operating at the expected load

levels considered in the potential near-term developments on the island. The measured

strains and projected equivalent stress magnitudes and ranges are relatively small and well

below the service level stresses for which the original designers would likely have

designed. The strain ranges and numbers of cycles are also relatively low by comparison to

other similarly aged bridges instrumented by the research team. If the present operating

conditions were to remain, the bridge would likely continue to operate indefinitely, barring

unforeseen natural or manmade hazards.

10

If the bridge were subjected to higher numbers of heavier load cycles, of the numbers

considered in the proposed applications: 148 trips per weekday, rounded to 150 trips =

39,107 trips annually = 1,955,350 trips in a 50 year life, the anticipated effect on the

embedded reinforcing steel can be estimated. Considering the ambient traffic stress ranges

collected, there would conservatively be approximately 9.57days * 150trips/day=1,436

additional events at each location that would have been measured at stress ranges (taking

the maximum from either Table 2a or 2b and assuming all days of measurement were

weekdays) representative of the test truck. Artificially adding these into the results

collected, the resulting equivalent stress ranges were recalculated and are shown in Table

7. As seen here there is a modest increase in the equivalent stress ranges, but they are still

of sufficiently low magnitude such that fatigue of the embedded steel is not likely even

with the increased volume and magnitudes. Based on field measurements of in-service

bridges and laboratory tests of large-size concrete girders under high-cycle fatigue we

expect that a 50 year service life on an interstate bridge will have equivalent damage

represented by 2 million cycles of repeated load causing stirrup stresses of around 14 ksi

(Higgins et al. 2007). The present and expected operating stresses are well below this

value. They were also well below the AASHTO fatigue threshold of 20 ksi (and 10 ksi at

bends) for fatigue of reinforcing steel. Another possible long-term performance question is

bond fatigue. Under large repeated service level stresses, bond fatigue may occur whereby

the steel-concrete bond softens around crack locations and crack widths can grow over

time. Given the projected reinforcing steel stresses described above, bond fatigue damage

is not likely. However, routine periodic inspections should continue to identify new

cracking and monitor existing larger width cracks to identify changes that may occur over

time.

Summary and Conclusions

Bridge 01496A was instrumented, monitored under ambient traffic loads, and tested under

controlled truck loads. The test truck load magnitude was expected to be similar to that

proposed in the possible near-term development. Based on the field work, analysis of data,

and analytical evaluation of the sections considered, the following conclusions are made:

11

The bridge is presently operating at the projected load levels considered in the

proposed near-term development on the island.

Presently, the measured stress ranges and numbers of cycles are small and few,

respectively.

Under the present operating conditions, the bridge should continue operational

performance well into the future, barring unforeseen natural or manmade hazards.

Increasing the volume of heavy truck traffic will produce marginal increases in the

equivalent stresses in the bridge. These stresses are sufficiently small so that

continued operational performance of the bridge is expected.

Based on LRFR rating and OSU risk indices determined at the instrumented

sections, the bridge is sufficient to safely carry the expected load magnitudes

represented by the test truck.

Routine periodic inspections should continue to identify new cracking and monitor

existing larger width cracks on the spans to identify changes that may occur over

time.

12

References

Groff, R., (2006). ODOT LRFR Policy Report: LiveLoad Factors for Use in Load and Resistance Factor Rating (LRFR) of Oregon’s State-Owned Bridges. ODOT Bridge Engineering Section, Salem OR. Higgins, C., A.-Y. Lee, T. Potisuk, and R.W.B. Forrest. (2007). “High-cycle Fatigue of Diagonally Cracked RC Bridge Girders: Laboratory Tests” ASCE Journal of Bridge Engineering, Vol. 12, No.2, pp. 226-236. Higgins, C., T. H. Miller, D. V. Rosowsky, S. C. Yim, T. Potisuk, T. K. Daniels, B. S. Nicholas, M. J. Robelo, A.-Y. Lee, and R. W. Forrest. (2004). Assessment Methodology for Diagonally Cracked Reinforced Concrete Deck Girders. FHWA-OR-RD-05-04, Final Report, SPR 350, SR 500-091. Miner, M. A. (1945). “Cumulative Damage in Fatigue,” Journal of Applied Mechanics, Vol. 12, Trans. ASME Vol. 67, pp. A159-A164.

13

Table 1a – Maximum strain measurements for test truck with trailer eastbound.

Direction BOX BOX BOX BOX RCDG RCDG RCDG RCDG

of Concrete Flex Ext Flex Int Shear Shear Ext Shear Int Flex Ext Flex Int

Travel Speed Position CH_1 CH_2 CH_3 CH_4 CH_5 CH_6 CH_7 CH_8

EB Slow inlane 2 21 31 12 4 2 27 51

EB Slow Center 3 26 39 35 9 10 66 99

EB Slow wronglane 6 39 40 77 16 15 125 91

EB Fast inlane 2 26 35 15 5 1 39 64

EB Fast Center 2 28 41 34 7 7 62 94

EB Fast wronglane 2 38 41 77 16 15 113 102

Maximum Strain (microstrain)

Table 1b – Maximum strain measurements for test truck with trailer westbound.




WB Slow inlane 4 35 40 77 14 15 119 97

WB Slow Center 2 22 36 25 7 6 51 92

WB Slow wronglane 2 20 29 16 5 4 25 50

WB Fast inlane 3 35 37 86 13 15 121 99

WB Fast Center 2 23 36 34 8 7 62 98

WB Fast wronglane 1 23 30 19 5 2 34 64

Maximum Strain (microstrain)

Table 2a – Strain range measurements for test truck with trailer eastbound.




EB Slow inlane 6 30 43 30 5 7 38 59

EB Slow Center 7 33 51 42 10 18 77 107

EB Slow wronglane 12 46 51 95 24 23 137 98

EB Fast inlane 6 35 47 33 7 5 51 75

EB Fast Center 5 36 52 41 9 14 77 105

EB Fast wronglane 7 45 52 86 22 20 128 114

Strain Range (microstrain)

Table 2b – Strain range measurements for test truck with trailer westbound.




WB Slow inlane 10 43 50 92 22 23 134 108

WB Slow Center 6 31 47 33 10 9 65 103

WB Slow wronglane 6 29 40 31 6 7 38 59

WB Fast inlane 9 41 47 99 20 20 137 112

WB Fast Center 5 31 48 40 9 16 78 110

WB Fast wronglane 6 32 42 34 7 5 50 76

Strain Range (microstrain)

14

Table 3 – Equivalent stress ranges from ambient traffic data.

Table 4 – Impact coefficients based on strain measurements for test truck with trailer.

BOX BOX BOX BOX RCDG RCDG RCDG RCDG

Travel Concrete Flexural Exterior

Flexural Interior

Shear Shear Exterior

ShearInterior

Flexural Exterior

FlexuralInterior

Direction CH_1 CH_2 CH_3 CH_4 CH_5 CH_6 CH_7 CH_8

WB 0.87 1.00 0.94 1.12 0.93 0.96 1.02 1.02

EB 0.33 0.96 1.04 1.00 0.98 0.95 0.90 1.12

Table 5 – Load distribution percentages based on strain measurements for test truck with trailer.

Direction of Travel

Loading Scenario

Bridge Member

Load Effect

ExteriorGirder/ Stem

InteriorGirder/ Stem

InteriorGirder/ Stem

Exterior Girder/ Stem

Applied to Loading Case

Westbound One Lane RCDG Shear 37% 41% 10% 13% For one lane statics

Westbound Two Lanes

RCDG Shear 25% 25% 25% 25% For two lane statics

Westbound One Lane RCDG Moment 41% 33% 17% 9% For one lane statics

Westbound Two Lanes

RCDG Moment 25% 25% 25% 25% For two lane statics

Westbound One Lane Box Girder

Moment 28% 32% 24% 16% For one lane statics

Westbound Two Lanes

Box Girder

Moment 22% 28% 28% 22% For two lane statics

Eastbound One Lane RCDG Shear 11% 6% 40% 42% For one lane statics

Eastbound Two Lanes

RCDG Shear 27% 23% 23% 27% For two lane statics

Eastbound One Lane RCDG Moment 9% 17% 31% 43% For one lane statics

Eastbound Two Lanes

RCDG Moment 26% 24% 24% 26% For two lane statics

Eastbound One Lane Box Girder

Moment 16% 24% 30% 30% For one lane statics

Eastbound Two Lanes

Box Girder

Moment 23% 27% 27% 23% For two lane statics

Equivalent Channel Stress Range

ID (ksi) Material Span CH_1 0.026 Concrete Box Girder CH_2 0.64 Flexural Steel Box Girder CH_3 0.73 Flexural Steel Box Girder CH_4 0.60 Stirrup Box Girder CH_5 0.28 Stirrup RCDG CH_6 0.24 Stirrup RCDG CH_7 0.59 Flexural Steel RCDG CH_8 0.73 Flexural Steel RCDG

15

Table 6 – Anticipated equivalent stress ranges for proposed operational level with trucks having load

effects consistent with the test truck (105.5 kips GVW).

Equivalent Channel Stress Range

ID (ksi) Material Span CH_1 0.039 Concrete Box Girder CH_2 1.24 Flexural Steel Box Girder CH_3 1.48 Flexural Steel Box Girder CH_4 1.66 Stirrup Box Girder CH_5 0.63 Stirrup RCDG CH_6 0.48 Stirrup RCDG CH_7 1.88 Flexural Steel RCDG CH_8 1.95 Flexural Steel RCDG

16

Fig. 1‐ Example of instrumented section with stain gage on reinforcing bar and displacement sensor across crack (flexural reinforcing bar in box girder shown).

Fig. 2‐ Concrete surface strain gage on exterior face of box girder stem near soffit of deck.

17

Strain gage and displacement sensor

Strain gage

CH7 StrainCH17 Disp

Gird

er1

Gird

er2

Gird

er3

Gird

er4

Bent 9

Bent 8

Bent 7

Bent 6

CH8 StrainCH18 Disp

CH6 StrainCH12 Disp

CH5 StrainCH16 Disp

CH4 StrainCH15 Disp

Web

1

Web

2

Web

3

Web

4

Bent 6

Bent 5

Bent 4

Bent 3

CH2 StrainCH21 Disp

CH1 StrainConcrete

Flow

Tra

velD

irect

ion

Wes

t-B

ound

Tra

velD

irec

tion

We

st-B

oun

d

CH3 StrainCH22 Disp

Spa

n6

RC

DG

Spa

n7

RC

DG

Spa

n8

RC

DG

Spa

n3

Box

Gird

erS

pan

4B

ox

Gird

erS

pan

5B

oxG

irde

r

Fig. 3‐ Schematic of instrumentation locations and channel identifications.

18

Time (sec)

Str

ain

(

)

0 3 6 9 12 15 18 21 24 27 30-20

0

20

40

60

80

100

120

140CH_1CH_2CH_3CH_4CH_5CH_6CH_7CH_8

Fig. 4a – Large ambient traffic event WB 9/9/2010, 9:11 am. Maximum strain = 121 microstrain: CH_7.

Time (sec)

Str

ain

(

)

0 3 6 9 12 15 18 21 24 27 30-20

0

20

40

60

80

100

120


Fig. 4b – Large ambient traffic event WB 9/9/2010, 3:36 pm. Maximum strain = 127 microstrain: CH_7.

19

Time (sec)

Str

ain

(

)

0 3 6 9 12 15 18 21 24 27 30-20

0

20

40

60

80

100

120


Fig. 4c – Large ambient traffic event WB 9/21/2010, 2:30 pm. Maximum strain = 123 microstrain: CH_8.

Time (sec)

Str

ain

(

)

0 3 6 9 12 15 18 21 24 27 30-20

0

20

40

60

80

100

120

140

CH_1CH_2CH_3CH_4CH_5CH_6CH_7CH_8

Fig. 4d – Large ambient traffic event EB 9/21/2010, 5:01 pm. Maximum strain = 126 microstrain: CH_8.

20

Fig. 5a‐ Loaded test truck with trailer for controlled tests of bridge.

Test Truck with Trailer: GVW=105.0 kips

GVW: 49.1 kips

Sin

gle

Dro

p

Sin

gle

Dua

l

Sin

gle

Sin

gle

Dua

l

Dua

l

Ste

er

GVW: 55.9 kips

Fig. 5b‐ Test truck axle spacing and weights.

21

RCDG Spans 6, 7, and 8: Section looking east

In lanes

On/over lane markers

Lane Markers

In lanes

On/over lane markers

Box Girder Spans 3, 4, and 5: Section looking east

Fig. 6‐ Illustration of test truck positions relative to supporting bridge structure.

22

Strain Range ()

Nu

mb

er o

f C

ycle

sYamhill Bridge #01496A

Ambient Traffic 9.57 days of data

5 6 7 8 9 10 20 30 40 50 60 70 80 90100 2001

2

3

57

10

20

30

5070

100

200

300

500700

1000

2000

3000

50007000

10000

CH_1CH_2CH_3CH_4CH_5CH_6CH_7CH_8

Fig. 7‐ Number of cycles and corresponding strain ranges for ambient traffic.

Moment (kip-ft)

Sh

ear

(kip

s)

0 250 500 750 1000 1250 1500 1750 2000 2250 25000

20

40

60

80

100

120

140

160

180

200

Mn, VnMn, VnMu, Vu for LRFR

Fig. 8a ‐ LRFR rating for RCDG at 31 ft from Bent 6.

23

Moment (kip-ft)

Sh

ear

(kip

s)

0 300 600 900 1200 1500 1800 2100 2400 27000

25

50

75

100

125

150

175

200

225 Mn, VnExpected Mean Mn, VnM, V Service Levels-3 sigma Mn, Vn-5 sigma Mn, Vn

Fig. 8b – OSU Risk Index for RCDG at 31 ft from Bent 6.

Moment (kip-ft)

Sh

ear

(kip

s)

0 200 400 600 800 1000 1200 14000

25

50

75

100

125

150

175

200


Fig. 9a ‐ LRFR rating for RCDG at 7.4 ft from Bent 6.

24

Moment (kip-ft)

Sh

ear

(kip

s)

0 200 400 600 800 1000 1200 1400 16000

25

50

75

100

125

150

175

200Mn, VnExpected Mean Mn, VnM, V Service Levels-3 sigma Mn, Vn-5 sigma Mn, Vn

Fig. 9b – OSU Risk Index for RCDG at 7.4 ft from Bent 6.

Moment (kip-ft)

Sh

ear

(kip

s)

0 300 600 900 1200 1500 1800 2100 2400 2700-25

0

25

50

75

100

125

150

175

200

225


Fig. 10a ‐ LRFR rating for box girder at 35 ft from Bent 6.

25

Moment (kip-ft)

Sh

ear

(kip

s)

0 300 600 900 1200 1500 1800 2100 2400 2700 3000-25

0

25

50

75

100

125

150

175

200

225

250

Mn, VnExpected Mean Mn, VnM, V Service Levels-3 sigma Mn, Vn-5 sigma Mn, Vn

Fig. 10b – OSU Risk Index for box girder at 35 ft from Bent 6.

Moment (kip-ft)

Sh

ear

(kip

s)

0 200 400 600 800 1000 1200 1400 1600 18000

20

40

60

80

100

120

140

160Mn, VnMn, VnMu, Vu for LRFR

Fig. 11a ‐ LRFR rating for box girder at 7 ft from Bent 6.

26

Moment (kip-ft)

Sh

ear

(kip

s)

0 200 400 600 800 1000 1200 1400 1600 1800 20000

20

40

60

80

100

120

140

160

180Mn, VnExpected Mean Mn, VnM, V Service Levels-3 sigma Mn, Vn-5 sigma Mn, Vn

Fig. 11b – OSU Risk Index for box girder at 7 ft from Bent 6.

27

APPENDIX A

28

Time (sec)

Str

ain

(

)

20 28 36 44 52 60 68 76 84 92 100-20

0

20

40

60

80

100

120


Fig. A1‐ Strains for westbound in‐lane, slow speed, test truck with trailer.

Time (sec)

Dis

pla

cem

ent

(in

)

20 28 36 44 52 60 68 76 84 92 100-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A2‐ Crack displacements for westbound in‐lane, slow speed, test truck with trailer.

29

Time (sec)

Str

ain

(

)

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30-20

0

20

40

60

80

100

120


Fig. A3‐ Strains for westbound in‐lane, fast speed, test truck with trailer.

Time (sec)

Dis

pla

cem

en

t (i

n)

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A4‐ Crack displacements for westbound in‐lane, fast speed, test truck with trailer.

30

Time (sec)

Str

ain

(

)

40 48 56 64 72 80 88 96 104 112 120-20

0

20

40

60

80

100

120


Fig. A5‐ Strains for westbound over center stripe, slow speed, test truck with trailer.

Time (sec)

Dis

pla

cem

ent

(in

)

40 48 56 64 72 80 88 96 104 112 120-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A6‐ Crack displacements for westbound over center stripe, slow speed, test truck with trailer.

31

Time (sec)

Str

ain

(

)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15-20

0

20

40

60

80

100

120


Fig. A7‐ Strains for westbound over center stripe, fast speed, test truck with trailer.

Time (sec)

Dis

pla

cem

en

t (i

n)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A8‐ Crack displacements for westbound over center stripe, fast speed, test truck with trailer.

32

Time (sec)

Str

ain

(

)

50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130-20

0

20

40

60

80

100

120


Fig. A9‐ Strains for westbound wrong lane, slow speed, test truck with trailer.

Time (sec)

Dis

pla

cem

ent

(in

)

50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A10‐ Crack displacements for westbound wrong lane, slow speed, test truck with trailer.

33

Time (sec)

Str

ain

(

)

20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40-20

0

20

40

60

80

100

120


Fig. A11‐ Strains for westbound wrong lane, fast speed, test truck with trailer.

Time (sec)

Dis

pla

cem

en

t (i

n)

20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A12‐ Crack displacements for westbound wrong lane, fast speed, test truck with trailer.

34

Time (sec)

Str

ain

(

)

40 48 56 64 72 80 88 96 104 112 120-20

0

20

40

60

80

100

120


Fig. A13‐ Strains for eastbound in lane, slow speed, test truck with trailer.

Time (sec)

Dis

pla

cem

en

t (i

n)

40 48 56 64 72 80 88 96 104 112 120-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A14‐ Crack displacements for eastbound in lane, slow speed, test truck with trailer.

35

Time (sec)

Str

ain

(

)

20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40-20

0

20

40

60

80

100

120


Fig. A15‐ Strains for eastbound in lane, fast speed, test truck with trailer.

Time (sec)

Dis

pla

cem

ent

(in

)

20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0.0016

0.0018

0.002CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A16‐ Crack displacements for eastbound in lane, fast speed, test truck with trailer.

36

Time (sec)

Str

ain

(

)

40 48 56 64 72 80 88 96 104 112 120-20

0

20

40

60

80

100

120


Fig. A17‐ Strains for eastbound over center stripe, slow speed, test truck with trailer.

Time (sec)

Dis

pla

cem

ent

(in

)

40 48 56 64 72 80 88 96 104 112 120-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0.0016

0.0018

0.002CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A18‐ Crack displacements for eastbound over center stripe, slow speed, test truck with trailer.

37

Time (sec)

Str

ain

(

)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20-20

0

20

40

60

80

100

120


Fig. A19‐ Strains for eastbound over center stripe, fast speed, test truck with trailer.

Time (sec)

Dis

pla

cem

ent

(in

)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0.0016

0.0018

0.002CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A20‐ Crack displacements for eastbound over center stripe, fast speed, test truck with trailer.

38

Time (sec)

Str

ain

(

)

30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110-20

0

20

40

60

80

100

120


Fig. A21‐ Strains for eastbound wrong lane, slow speed, test truck with trailer.

Time (sec)

Dis

pla

cem

en

t (i

n)

30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110-0.0005

-0.00025

0

0.00025

0.0005

0.00075

0.001

0.00125

0.0015

0.00175

0.002

0.00225

0.0025CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A22‐ Crack displacements for eastbound wrong lane, slow speed, test truck with trailer.

39

Time (sec)

Str

ain

(

)

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25-20

0

20

40

60

80

100

120


Fig. A23‐ Strains for eastbound wrong lane, fast speed, test truck with trailer.

Time (sec)

Dis

pla

cem

ent

(in

)

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0.0016

0.0018

0.002CH_12CH_13CH_14CH_15CH_16CH_17CH_18

Fig. A24‐ Crack displacements for eastbound wrong lane, fast speed, test truck with trailer.

final report on field testing and analysis of bridge ...€¦ · three crc deck-girder approach...

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