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5MONDAY, OCTOBER 18, 2010 | SECTION 1 | CHICAGO TRIBUNE
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The highway bridge over SaltCreek in Elmhurst is arguablythe safest water crossing in Illi-nois. It should be, because it hasbeen monitored for trouble morethan any other bridge in the state.
The span, near the intersectionof IllinoisHighway 83and St.Charles Road,faces no sud-den danger offalling down,according tothe IllinoisDepartmentof Trans-portation. Buton a 1-to-8 scaleassessing therisk of thebridge founda-tion failingunder certain
circumstances, the Salt Creekbridge was rated a 3 by IDOT,where 1is the worst.
Rising and falling water levelsstir up the bridge’s creek-bedfoundation and cause soil erosionat times of flooding and seasonalchanges.
IDOT officials conferred withresearchers from the Universityof Illinois at Chicago, who arepaying attention to the areawhere the bridge piers are se-cured underwater. It is the focusof an experimental project toremotely monitor the safety and“structural health” of bridgesaround the clock, like constantlychecking a hospital patient’s vitalsigns.
Bridge safety experts say theUIC project represents an extrasafety net needed to keep tabs onthe increasing inventory of defi-cient and functionally obsoleteinfrastructure in the U.S.
The project is under way threeyears after the nation received ashocking wake-up call about thepoor condition of U.S. bridgeswhen the Interstate Highway35W Bridge over the Missis-sippi River in Minneapolis col-lapsed Aug. 1, 2007. Thirteenpeople died and more than 145were injured when the bridgecrumbled beneath their vehicles.
Being able to electronicallymonitor bridges 24 hours a daywould represent a safety break-through, according to structuralengineering experts. With no hintof what was to occur, the I-35Wbridge was visually inspectedshortly before the disaster.
At the Salt Creek bridge, 14fiber optic sensors — consisting
mostly of long threads of glass asthin as fishing line — have beeninserted into rods placed in thewater near the piers by UIC engi-neering researchers. The teamuses computers to remotely mon-itor the bridge for soil erosionthat could lead to the bridge foun-dation kicking out and collaps-ing. Sensors can also be designedto detect early signs of excessivestrain and vibration that couldlead to cracks in the concretebase, tilting and, if potentialproblems were to go undetected,collapse.
Conditions at the bridge canchange swiftly, as Farhad Ansari,the UIC professor leading the
project, experienced Thursday.After a heavy rain earlier in theweek accelerated water flow andstirred the sand and rocks in thecreekbed, Ansari and doctoralstudent Chad Fischer, both wear-ing chest-high waders, enteredSalt Creek to check the sensors.The water level was only aboutcalf-high until Ansari got close toone of the support piers. He tookanother step and sank almost tohis hips.
“I didn’t dare take any moresteps after that because I wouldhave dropped down six feet, and Idon’t want to drink the water,”said Ansari, who heads the civiland materials engineering de-
partment at UIC.The high-tech equipment,
which tracks wavelength fluc-tuations resulting from factorsranging from traffic loads to theweather, serves as a virtual nerv-ous system for the entire bridge.It also offers an alternative tosending divers into murky ordangerous waters to inspect fordeterioration called “scouring.”
“You would see large swings inthe wavelength activity if some-thing bad were happening,” AliZarafshan, a doctoral student instructural engineering, said as hestood on the banks of the creekand pointed to a laptop computertracking the bridge in real time.
Bridge scour compromises theintegrity of a structure by remov-ing sand and rocks from aroundbridge abutments or piers andscooping out scour holes. It is themost common cause of bridgefailures in the United States,mostly affecting single-spanbridges with vertical wall abut-ments, like the Salt Creek bridge,officials said.
The bridge is the only struc-ture in Illinois outfitted with thesensors monitoring scour depth.Other types of sensors can detectcracks, corrosion and other po-tentially catastrophic flaws.
Ansari has installed similarmonitoring systems on theBrooklyn Bridge in New Yorkbecause of major cracks found inthe suspension bridge’s vaultsystem, and on the Sheng LiBridge, a cable-supported spanover the Yellow River in China.
His goal is to reduce the cost ofsuch monitoring devices, whichnow cost about $140,000 for asystem covering a four-spanbridge, and to work with compa-nies to make a commercial ver-sion of the research tool.
Many bridges in Illinois, in-cluding those over the Missis-sippi and the historic draw-bridges spanning the ChicagoRiver downtown, also merit extrascrutiny because of their age, thelarge number of vehicles crossingeach day and outmoded designsthat lacked redundancies to pre-vent a failure in one section of abridge from leading to a collapse,Ansari said.
IDOT officials are evaluatingthe Salt Creek experiment beforedeciding whether to proceed withremote monitoring of more brid-ges.
The Illinois State Toll High-way Authority is paying closeattention to Ansari’s work. PaulKovacs, the toll authority’s chiefengineer, and other tollway staff-ers met with Ansari last week todiscuss a monitoring projectfocusing on some bridges alongthe 286-mile toll road system.
The tollway officials showedparticular interest in crack andscour sensors, Ansari said. Toll-way officials, however, declinedto identify specific bridges thatwould be candidates for remotemonitoring.
“Bridges pose some real oppor-tunities for us to have ongoingmonitoring so we can be fullyconfident they are structurallysound,” said Kristi Lafleur, thetollway’s executive director.“That is a powerful tool for us. Nohuman being would ever be ableto do that.”
Contact Getting Around at [email protected] or c/o theChicago Tribune, 435 N. MichiganAve., Chicago, IL 60611. Readrecent columns at chicagotribune.com/gettingaround.
Sensors keep bridge data flowingFiber opticthreads monitorbridges for soilerosion, damage
JonHilkevitch
GettingAround UIC Engineering professor Farhad Ansari, left, and engineering student Chad Fischer wade through Salt
Creek to check on monitors under a bridge along Illinois Highway 83. CHRIS WALKER/TRIBUNE PHOTO
TRIBUNESOURCE: Farhad Ansari, University of Illinois at Chicago
As water moves along a bridge’s base, it washes out soil. This is called scour
Scour sensors placed along bridge detect soil erosion
Fiber optic sensors detect cracks, corrosion and vibration in the bridge
A computer at the site continuously gathers data from bridge and
scour sensors.
Data is transmitted by a cellular antenna and can be monitored anywhere over the internet.
Researchers at the University of Illinois at Chicago hope technology they have developed — which uses rugged fiber optic cables, bridge sensors and the Internet — will allow agencies to keep constant tabs on the
condition and safety of any outfitted bridge.
New technology offers a continuous inspection of bridges
Fiber optic cable
Paul Larson doesn’t celebrate Hallow-een. Instead, he spends Oct. 31in a worshipservice that’s a ritual feast with offerings ofsweet cakes and ale to the ancestors.
For many pagans such as Larson, Oct. 31is the autumnal newyear called Samhain, atime when the veil be-tween the spiritualworld and the world aswe know it is the thin-nest and it’s possible tocontact those who havepassed away.
“We honor the ances-tors by casting a magicalcircle of protection andinvoking the divinepowers in the form of agod and goddess,” saidLarson, a white-haired63-year-old with a profes-sorial air. “And there’schanting to create and
build energy within the group, and some-times a bonfire.”
A member of the Wiccan branch of pa-ganism, Larson knows that some peopleequate his religion with evil witchcraft anddevil worship and that evokes a wide rangeof images and controversies — from peoplewearing conical hats, black gowns andmedallions to the recent dust-up over GOPU.S. Senate candidate Christine O’Donnell,who has taken flak for saying she “dabbledinto witchcraft.” But Wiccans don’t likethat she linked their religion to Satanism.
Larson said the reality is that paganismhas nothing to do with Satan worship andthat the pagan tent is large enough to in-clude people who do identify as witches(although not the green-faced, wart-ladenstereotypes) and people like Larson, aChicago attorney who has a doctorate inpsychology and who’s on the faculty of theChicago School of Professional Psychology.
He said he spent years searching reli-gions for the proper spiritual fit.
“I was born into the Mormon faith, con-verted to the (Episcopal) faith and thenbecame a Buddhist,” Larson said. “But Ihad been investigating paganism since1969.”
About eight years ago, after experienc-ing the loss of several family members andfriends, he began to concentrate on pagan-ism.
“I still consider myself a hyphenatedAmerican, a Mormo-Episco-Buddhi-pa-gan,” said Larson, who has a Buddhiststatue in his office located in the Merchan-dise Mart. The statue isn’t too far from thecertificate that shows he was ordained overthe summer as a Wiccan minister.
“Eight years ago as I was going throughmy (reinvention), I stopped believing inreligious exclusivity, that there was onepath through which the divine speaks,” hesaid.
Larson said that despite the misconcep-tions, contemporary paganism has becomeattractive to more people, particularlyyoung people, over the last three decadesbecause of its reverence for the environ-ment and its embrace of feminism. It alsoallows for a diversity of thought and beliefsystems that aren’t bound by a singulardoctrine.
“There’s no formal book or scripturethat’s considered divinely revealed,” Lar-son said. “Pagans don’t have to reconcile acreation story written millennia ago withthe findings of modern science. Conse-quently, most pagans are quite comfortablewith a scientific world view including such
specific ideas as evolution.”And pagans don’t proselytize.It’s not clear how many Americans iden-
tify as pagans because many fear theiracknowledgement would lead to discrimi-nation. (As Larson puts it, “It’s hard tocome out of the broom closet.”)
But a 2008 American Religious Identifi-cation Survey out of Trinity College inConnecticut suggests that practitionersmay be more comfortable identifying aspagans. According to the survey, thosecalling themselves pagans increased from140,000 to 340,000 between 2001and 2008. Thenumber of Wiccans grew from 134,000 in2001and 342,000 in 2008.
Larson said the increase in part is be-cause the religion has become more accept-able in the mainstream.
Three years ago, Larson’s church, theWisconsin-based Circle Sanctuary, was aplaintiff in a decade-long lawsuit that gotthe U.S. Department of Veterans Affairs toadd the Wiccan pentacle, or five-point star,to the list of religious emblems allowed onveterans’ graves. The government settledthe lawsuit.
“Just as Christians have the cross andJews have the Star of David, we wanted toallow fallen pagan soldiers the same dig-nity of having the pentacle placed on theirgovernment-paid-for tombstones,” Larsonsaid.
After years of protests and advocacywork, Circle Sanctuary and others weresuccessful in getting colleges (includingNorthern Illinois University), hospitalsand prisons to open their chaplaincies topagan ministers. Larson ministers to in-mates at Chicago’s Metropolitan Correc-tion Center and a prison in Wisconsin.
“As pagans, they feel isolated from otherinmates who don’t share their back-ground,” Larson said. “I’ve had severalinmates tell me that I’ve been the only onewho has visited them.”
As a professor, Larson teaches hypnosis,and he interacts with students who typi-cally come to psychology with a fairlysecular point of view. He said many of hisstudents don’t care about his religiousbeliefs. Consequently, he’s been able tomaintain good relationships with studentsof different faiths.
He said he’s begun meeting more youngpeople born into paganism, and that wouldhave been unheard of in his generation.
“More people see the importance ofreconnecting with nature as technologypushes us further away from it,” Larsonsaid. “A lot of us feel, whether we’re paganor not, that we’ve lost touch with the natu-ral processes of the world and we need toreconnect with cycles of the seasons.”
“It’s hard to come out of the broom closet,”
but it’s getting easier, says Paul Larson, aChicago attorney and Wiccan minister.
WILLIAM DESHAZER/TRIBUNE PHOTO
Wiccan minister says pagans are a big-tent group
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