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After the Storm
 

After the Storm

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North American Tunneling Journal article on the aftermath of Hurricane Sandy in the New York subway system - January 2013

North American Tunneling Journal article on the aftermath of Hurricane Sandy in the New York subway system - January 2013

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    After the Storm After the Storm Document Transcript

    • HURRICANE SANDY16 NORTH AMERICAN TUNNELING JOURNALLOWER MANHATTAN’S FINANCIALDISTRICT has seen its fair share ofdestruction, most notably when the WorldTrade Centre’s twin towers were destroyed byterrorist attacks on September 11, 2001.Following Hurricane Sandy, a Category 1storm that hit New York on October 29, it wasthe southern tip of Manhattan that bore thebrunt of the destruction wrought by the storm- at least in terms of tunnel infrastructure.Seven of the city’s subway tunnels wereflooded during Sandy, and all but three of thetunnels were up and running little more thana week after Sandy hit. However, theseremaining sections of subway lines were stillout of operation when NATJ went to press inearly December, and all three sections arelocated in lower Manhattan. The continuingclosure of these line sections - the R trainsuspended between 34 St-Herald Square &Jay St-Metrotech, the J/Z trains suspendedsouth of Chambers Street, and the 1 trainsuspended south of Rector Street - leaves WallStreet commuters with just one subway line,the 4-5 line, to cram on to (Figure 1).Perfect stormWhen Sandy hit New York, its storm surgecoincided with a new moon high tide toinundate Lower Manhattan with floodingthat those working on the city’s subwaysystem had never witnessed before. It isestimated that 66 million gallons of waterhad to be pumped out the subway systemfollowing the storm.New York City Transit Chief MaintenanceOfficer, Joseph Leader, says floodingprotection such as sandbags and temporaryinflatable barriers deployed in vulnerable partsof the system were simply overwhelmed bythe storm surge that hit Lower Manhattan.“Even with all the barricades it was just notgoing to work,” says Leader. “It was almost aCategory 2 storm, and the surge was nearly14 feet high.”After thestormMany of New York City’s key road and railtunnels were inundated with salt waterduring Hurricane Sandy. Recovery workcontinues well into the Christmas period,with the total repair bill expected to reach$3 billion. John McKenna reportsNATJ_1212_SANDY_016_019.qxd:Feature 15/12/12 18:06 Page 16
    • HURRICANE SANDYNORTH AMERICAN TUNNELING JOURNAL 17Despite flood defenses being overwhelmedby the water rushing through the tunnels,Leader said he was confident the subway’spumping system would move the water outquickly enough to avoid any lasting damageto the infrastructure. However, what Leaderhadn’t anticipated was that all of LowerManhattan would lose its electricity supplydue to water infiltrating one of utility ConEdison’s substations. Power only began to berestored four days after the storm.Without power and with vital structural andelectrical components resting in saltwater,New York’s Metropolitan TransportationAuthority (MTA) sought alternative solutionsto pump out the water. Alongside placingportable diesel-fuelled high-capacity pumps atstrategic locations throughout the subwaysystem, the MTA also deployed its three“pump trains”. Each train comprises a flatbedrail truck carrying pumps capable of pumping5,400 gallons per minute.“What an amazing asset those pump trainswere,” says Carmen Bianco, New York CityTransit Senior Vice President for Subways.“We pumped 66 million gallons out of oursystem and those trains were instrumental.We know that if we had more of those wewould have been able to do even better, sowe are now looking for trains not in service toconvert so that we have a few more.”The search for more pump trains isunderstandable given the anticipated $4.75billion of damage that Sandy has inflicted onthe MTA’s entire system, with just under $3billion of that relating to tunnel infrastructure,and $2.2 billion relating to the subways alone(see table on p18).No signalBy far and away the biggest single item onSandy’s tunneling repair bill is the estimated$770 million it will cost to restore theSubway’s signalling system to pre-stormconditions. With power out in LowerManhattan, much of the area’s subwaysignalling equipment was flooded withsaltwater for days. Indeed, it is the damagecaused to signalling equipment in theSubway’s Montague tunnel that is causing avital section of the R-Line in LowerManhattan to remain suspended monthsafter the storm.“The Montague tunnel for the R servicecontains relay rooms and complicatedequipment,” says Bianco. “That tube floodedfrom floor to ceiling and we had very complexsignal equipment totally underwater. We havehad to rebuild most of that equipment andthat’s taking some time to do.”Montague’s problems were compounded,says, Leader, not only by the lack of powerfrom Con Edison to utilise pumps, but by thefact that when power came back its keypump room was still unusable.“One of the main pump rooms wascompletely submersed,” says Leader. “Mypeople temporarily made a control panel forthe pump room to get it going, and as webegan to bring back power we then werelooking for faults and beginning a bigreplacement process.”As Leader hints at, both on the subwaysand the road tunnels (see below) much of thereplacement of electrical equipment has beena temporary “patch” job of replacing faultycomponents to get New York moving again.However, the MTA is under no illusions thelong term impact Sandy could have on thesesystems. For example, it put the cost ofbringing the Brooklyn Battery (now known asthe Hugh L. Carey tunnel) back to operationat just $10 million, while the cost of properlyrestoring it, including all its electrical systems,is put at $400 million.Speaking about the damage to subwaysignalling equipment, Bianco adds: “Becauseof the salt infiltration we really don’t know theimpact that it will have on the life ofcomponents.”One area of the subway where signallingequipment was successfully defended was theon L service, also known as the BMT CanarsieLine, at a section underneath 14th Street. Theline is a vital east-west link running acrossManhattan all the way out to Canarsie, inBrooklyn. The majority of the line is aboveground but goes into a tunnel at 14th streetthat is susceptible to flooding. It also operatesan expensive computer signalling system. As aresult, Thomas F. Prendergast, President, MTANew York City Transit, says the decision wasNEast RiverManhattanBridgeBrooklynBridgeWilliamsburgBridgeQueensMidtownTunnelHollandTunnelBrooklynBatteryTunnelRutgersSt.TunnelClark St.TunnelJoralemonTunnelBROOKLYNSt.MANH A T T A NChambers St.Tracks floodedChambers St.Rector St.Broad St.BowlingGreenWhitehall St.South FerryFlooded tothe ceilingSome of the stationswith visible floodingor pumping arenamed and circled.Pumping initially began atthe Joralemon Street Tunnel.The first tunnel connectingManhattan and Brooklyn,it was completed in 1907and is composed of twotubes about 4,000 feet long.Later on October 29,pumping had begun at theRutgers Street Tunnel andthe Clark Street Tunnel.The and tunnels alsoflooded, but are not shownon this map. Pumping beganat the Steinway tubes, whichcarry the trains.L 77MZFJZJQBNDA C234 51RLJay St-MetrotechHerald SquareContinued suspensions (dashed lines)The R train is suspended between 34St-Herald Square & Jay St-MetrotechThe A train is suspended south of Howard Beach, replaced with a shuttle trainon the Rockaway Peninsula.The J/Z trains are suspended south of Chambers StThe 1 train is suspended south of Rector Street.Fulton StebHHotaameChrsbeerdksHer SacSSSebebeerbeerqoMqMMAAeANHdald SNeSHerald Sers StQdamberHHHfloo edquareHHbHqMMNHAAHHANHareHSqumbeChMMChHHChambers St.SqSSqNNNHHHHHHHHHHHHHHdHacks floodedracks floodedb rs t.mamberhambers St.HNAAeMMerHQZJHerald SquareTMMA ATA T NA NNTBBATAAA TiamsbamsbNgAATTTAWidLBMJDLZrr4ct5544A4Aectogwwweeeeto Nultdn SttSng dro d StSnStSn Saaeg BNNNgngtrrrehonA5rehoadutehFuAAStd SBroatehWhityWhyrerrghall SWhitehall SBroBro St.end StGreenwlw inwlingoSBo Broad St.Fuct .Nla k SuFu44R2555RR1Rector St.t.Fulton StBBROLLLeRAYSYMMMJaJ MJJ SOy etrotechMMJaJaYRLMeRYKOFBRLJaJJaJa MeMMMMMMMMMay St MStJay St MMS MJaNYecLLLYLYFKKKLKLOOOt-RROBBBBRBRBRBRt.nAAFADDCCJaJay St-Metrotech3ZOpposite page (below left):Water floods the Hugh L.Carey Tunnel (formerly theBrooklyn-Battery) during thehurricane; (top left) MTAcrews inspect the L train’stunnel under the East RiverOpposite (top right) andbelow: South Ferry subwaystation was heavily damagedby salt water flooding duringHurricane Sandy’s unprece-dented 13ft storm surgeLeft: A pump train worksaround the clock on the Ltrain’s East River tunnelFigure 1: Map of Lower Manhattan showing some of thesubway and road tunnels affected by the HurricaneNATJ_1212_SANDY_016_019.qxd:Feature 15/12/12 18:06 Page 17
    • made to remove the signalling equipment.“The Canarsie tube was seen as critical,” saysPrendergast. “Transponders for the signallingsystem were bagged, sealed and taken awayto high ground.”He adds that he regrets that such anapproach wasn’t possible for the entiresubway system, as there was insufficient timeto both remove signalling equipment andsafely evacuate people from the city. “If wewere going to remove all signal equipment,we would have to do it days in advance,” hesays. “And then you can’t run the trains toget people out.”In addition to signalling damage, exposureto saltwater can severely damage the qualityof the rails. Prendergast says that once powerand signalling systems came back on inpreviously flooded sections, trains would besent out on test runs for up to 24 hoursbefore the lines were reopened to the public,and this was not just simply to make sure thateverything worked. “Once you stop operatingfor a few days the rails start rusting and canlose the conductivity that allows it to connectto the signal system,” says Prendergast. “Sothe trains aren’t just testing the signals, they’realso polishing the rails.”Scenes of devastationAs if having your signals flooded withsaltwater wasn’t enough, on the J/Z line toBroad Street a fire broke out on the southernsection of the line, melting all the electricalequipment. This led to the line still beingsuspended south of Chambers Street as NATJwent to press. Leader says it is thought thefire started in an un-flooded area wherenonetheless some water managed to find itsway to meet with third rail cables coming outof a circuit breaker house. “The fire at BroadStreet melted a couple of hundred cables,every individual circuit,” he adds.Like Broad Street, another station thatremains closed is South Ferry station. SouthFerry, located on the southernmost tip ofManhattan, only opened in 2009. However, itis now in need of a full overhaul after it, alongwith the neighboring Whitehall station on theR line, bore the brunt of Sandy’s storm surgeas it slammed into Manhattan.“At South Ferry the entire track wasflooded, and the flood continued up to 4 feetin the mezzanine level,” says Bianco.“We lost a number of escalators among alot of other equipment, and we are probablylooking at couple of months at least tounderstand just how bad the damage is.”The MTA has put the total combined costof restoring South Ferry and Whitehall to pre-Sandy conditions at $600 million.Roads to recoveryWhile it looks set to be a slow road torecovery for South Ferry and Whitehallstations, both of Manhattan’s key roadtunnels that were heavily flooded have fullyreopened. This is all the more remarkablewhen you consider that engineers pumpedout 66 million gallons of water from theBrooklyn Battery (now known as Hugh L.Carey tunnel) alone – six million more thanthe entire amount of water drained fromsubway tunnels.The Brooklyn Battery is a 9,118ft (2,779m)long twin tube tunnel, each tube with adiameter of 31ft (9.5m). Linking Brooklyn withthe southern tip of Manhattan, the tunnel,like the South Ferry and Whitehall subwaystations, was overwhelmed by Sandy’s stormsurge. Water not only filled the tunnel floor toceiling, but continued 65ft (20m) up thetunnel’s mid-pont ventilation shaft atGovernor’s Island. Unfortunately the tunnel’sentire pumping system is also at this location.“The pumping system in the tunnels wereall destroyed, submerged,” says FacilityEngineer at the Hugh L. Carey Tunnel, RomoloDeSantis. Portable pumps with a capacity of4,000 gallons per minute were deployed atthe Brooklyn end of the tunnel, followed bymore pumps being delivered to Governor’sIsland and dropped down the ventilationshaft. However, this makeshift solution wasrelatively successful: Pumping began the dayafter the storm, and eight days later it wasempty, if not dry.“Our major concern is the ceiling panels,”says DeSantis. “They are aluminum framewith sheet metal with porcelain veneer, andwater is trapped inside the panes. We had todrill some of the panels to create weep holes,and we are now monitoring them.”HURRICANE SANDY18 NORTH AMERICAN TUNNELING JOURNALDescription Cost ($ mil)SubwaysSouth Ferry / Whitehall restoration 600Track restoration 300Signals restoration 770East River Tunnels - Systems restoration of damages due to flooding 100Other infrastructure restoration, such as tunnel lighting, vents, pumps, structures, 450communications, and powerSubway Subtotal 2,220Road tunnelsHugh L. Carey Tunnel (Brooklyn Battery): Emergency Restoration Work 10Queens Midtown Tunnel: Emergency Restoration Work 8Hugh L. Carey Tunnel: Replacement of tunnel interior, ceilings, walls, roadway, 400lighting, conduitQueens Midtown Tunnel: Replacement of tunnel interior, ceilings, walls, roadway, 350lighting, conduitQueens Midtown Tunnel (North and South tubes, vent buildings etc.) security 1infrastructure (power, fiber optic, CCTV cameras and Access Control) replacement andrelocation (Does not include Engineering Design Cost)Hugh L. Carey Tunnel (East &West tube and vent buildings) Security infrastructure (power,fiber optic, CCTV) replacement and relocation (Does not include Engineering Design Cost) 0.5Road Tunnels Subtotal 769.5Total cost of restoring New York tunnels hit by Sandy 2,989.5Table 1: Hurricane Sandy underground infrastructure related damagesWhitehall Street and South Ferry were twoof the worst affected subway stationsPump train activity in the L Traintunnel on Monday, November 5NATJ_1212_SANDY_016_019.qxd:Feature 15/12/12 18:06 Page 18
    • Romolo describes the state of the tunnel –from the panels to electrical systems – asrunning “on temporary”, short-term fixes andreplacements of components where needed toget the tunnel open as soon as possible. Andgiven the deluge it suffered, it was openimpressively fast: One lane in the east tubewas opened to buses on November 12,followed by cars allowed into one tube onNovember 17, and fully reopened November19, three weeks after the storm.The Queens Midtown tunnel was alsoflooded floor to ceiling, but opened muchsooner than the Brooklyn Battery, thanks inpart to its shorter length (at 6545ft long), butalso the fact that its pumping systems arelocated at either end of the tunnel, rather thanin the middle as for the Brooklyn Battery. Thismeant the pumps were not inundated andwere able to begin pumping with hours of thestorm hitting.Facility engineer John Pfister says that bySunday 4, just six days after the storm, he wasable to walk through the tunnel to assess thedamage. “We assessed what we thought theminimum functionality that could allow thepublic in the tunnel,” he says.Again, many of the tunnel’s electricalcomponents had to be replaced, and again thetunnel is far from being fixed for the longterm. But Pfister’s team was able to reopen thetunnel to the public by Friday 9 November.Future proofDespite its unprecedented scale, Bianco isunder no illusions that Sandy will not be thelast super storm he sees in his lifetime. “Wedon’t know why – that’s not for us guys toget into - but these major storms arebecoming more frequent and we need to beprepared,” he says. “So we are talking abouthardening the system. Looking at where wewere vulnerable, such as different signalsystems that will stop weather infiltration.”In addition to relatively small scaleimprovements such as building more pumptrains, the City of New York is also looking atgrander plans such as floodgates, while theMTA is considering an innovative solution forprotecting its tunnels – tunnel plugs.The Resilient Tunnel Plug (RTP), developedby the Department of Homeland Security(DHS) along with Pacific Northwest NationalLaboratory, West Virginia University and ILCDover, is a 16.2ft diameter, 32ft long inflatablestructure. The RTP has been developed forisolating sections of transit or rail tunnels inresponse to an event such as flooding, releaseof chemical/biological agents, or other threats.While the DHS claims it is a long way frombeing commercially viable, Bianco insists thatthe MTA will look at the product at that “thedoor is open”MTA New York City Transitcrews work to restore the SouthFerry subway stationGeotechnical,Mineral Explorationand Horizontal Coringwww.ruendrilling.comP.O. Box 267 • 2320 River Road,Clark Fork, Idaho, USA 83811Phone 208-266-1151Fax 208-266-1379USAModesto, California, Phone 209-988-4261Bozeman, Montana, Phone 406-586-6266Horizontal Coring for Tunnel InvestigationNORTH AMERICAN TUNNELING JOURNAL 19NATJ_1212_SANDY_016_019.qxd:Feature 15/12/12 18:06 Page 19