Snags drive up cost of new span’s construction

The Times-Tribune - - Front Page - BY BORYS KRAWCZENIUK

TSTAFF WRITER he cost of the new Har­ri­son Av­enue Bridge nearly dou­bled from orig­i­nal es­ti­mates be­cause state en­gi­neers’ ini­tial de­signs proved flawed and un­fore­seen cir­cum­stances cropped up dur­ing construction.

State Depart­ment of Trans­porta­tion en­gi­neers pegged construction at $13.47 mil­lion, but so far construction costs for the project are $25.37 mil­lion. Pen­nDOT of­fi­cials do not ex­pect ma­jor ad­di­tional costs, if any.

Over­all, the cost stands at about $30.8 mil­lion af­ter fac­tor­ing in the cost of de­signs, en­gi­neer­ing, in­spec­tions and pur­chases of homes to make way for the new bridge.

The bridge should open next month right next to the ex­ist­ing bridge, but with a dif­fer­ent align­ment con­nect­ing Scran­ton’s Hill Sec­tion to South Scran­ton.

The mis­cal­cu­la­tions also de­layed com­ple­tion.

Once ex­pected to wrap up by July, the project won’t fully end un­til at least the spring, ac­cord­ing to Pen­nDOT. Crews still must de­mol­ish the cur­rent bridge and re­store about 250 feet of in­bound Cen­tral Scran­ton Ex­press­way, among other things.

To avoid a re­peat of what hap­pened, Pen­nDOT added an en­gi­neer to projects to re­view whether de­signed plans can ac­tu­ally be car­ried out, of­fi­cials said.

“We have taken steps to move for­ward in a dif­fer­ent di­rec­tion with that,” said Car­men J. DiPi­etro, the construction man­age­ment su­per­vi­sor whose team un­cov­ered the de­sign short­com­ings. “Dur­ing the de­sign process, I don’t think they had a clear pic­ture of how this was go­ing to be con­structed. And, it re­ally came back to bite us in construction.”

The project looked com­pli­cated from the out­set. De­sign­ers and con­trac­tors had to deal with ob­sta­cles such as rail­road tracks that carry the Elec­tric City trol­ley, the Lau­rel Line tun­nel the trol­ley trav­els through, Steam­town Na­tional His­toric Site trains, high-ten­sion power lines and the Cen­tral Scran­ton Ex­press­way.

The re­al­iza­tion the new bridge would cost more than ex­pected dawned on construction of­fi­cials early.

In Oc­to­ber 2014, Pen­nDOT awarded Minichi Inc. of Dupont a $17.72 mil­lion construction con­tract. That put the project $4.25 mil­lion over the orig­i­nal es­ti­mate.

Minichi and Pen­nDOT construction man­agers quickly re­al­ized the de­sign flaws.

“When we got here, the way they had pro­posed it would not work,” said Tom Bai­ley, Minichi’s project man­ager. “Ac­cess to get to both th­ese piers was a chal­lenge.”

Plans called for a bridge pier on both ends to sup­port the new bridge, which sits about 140 feet above Roar­ing Brook.

The de­sign as­sumed crews would build two plat­forms into sur­round­ing hill­sides about 40 feet above the sur­face where the piers would stand. Mas­sive cranes, with steel bits eight feet wide, would sit on the plat­forms and bore holes into solid rock for the piers on ei­ther side of Roar­ing Brook.

Minichi and Pen­nDOT construction man­age­ment of­fi­cials re­al­ized that wouldn’t work. The drills had to sit next to where the holes would start. DiPi­etro said the cranes also stood so tall they might have touched high-ten­sion power lines cross­ing the bridge.

Pen­nDOT’s plans lacked proper ac­cess roads for equip­ment to reach the land where the plat­forms would be built, ac­cord­ing to a Pen­nDOT doc­u­ment and DiPi­etro. The con­trac­tor had to build ac­cess roads on both sides of Roar­ing Brook. That in­cluded tear­ing out about 250 feet of the two in­bound lanes of the Cen­tral Scran­ton Ex­press­way for the ac­cess road for the south­ern pier job.

Pen­nDOT found an­other prob­lem on the north­ern, Hill Sec­tion side — a buried Scran­ton Sewer Author­ity sewage over­flow pipe un­der a 100-year-old stone arch. If Minichi rolled heavy equip­ment over that, the arch could crum­ble, block­ing water flow and spurring flood­ing in neigh­bor­hoods.

Pen­nDOT added construction of a con­crete cause­way over the arch for the equip­ment to travel.

Build­ing the ac­cess roads also re­quired re­in­forc­ing the hill­sides to avoid rock slides, which could af­fect the ex­press­way and the Steam­town train tracks. The re­tain­ing walls alone cost about $2.1 mil­lion.

En­gi­neers en­vi­sioned de­mol­ish­ing the old bridge dif­fer­ently, too. They thought cranes on the bridge could take it apart grad­u­ally start­ing in the mid­dle, then pulling back and re­mov­ing the arched sec­tions from ei­ther side. Lit­tle de­bris would fall into Roar­ing Brook.

Minichi and the en­gi­neers con­cluded re­mov­ing each sec­tion could weaken the re­main­ing struc­ture sup­port­ing the re­moval cranes, lead­ing to po­ten­tial col­lapses that dropped bridge de­bris and the cranes into the brook be­low.

“No­body felt com­fort­able ap­prov­ing any kind of draw­ings and putting any kind of heavy equip­ment on that bridge and re­mov­ing the deck,” DiPi­etro said.

The best way, they de­cided, will be to im­plode the bridge, but that meant de­bris could drop into the brook, af­fect­ing flow.

They plan to build a rock cause­way in the brook to catch de­bris and di­vert water flow through a cul­vert for a few days un­til the de­bris is re­moved.

The de­mo­li­tion en­tailed an­other po­ten­tial prob­lem never ac­counted for in orig­i­nal plans. Right next to the ex­ist­ing bridge, PPL Elec­tric Util­i­ties had a huge steel pole car­ry­ing ma­jor east-west power lines along the brook and over the bridge. PPL re­moved that pole and in­stalled a new one up­stream far­ther away from the bridge.

A project re­view dur­ing construction found the math­e­mat­i­cal model used to de­sign the new bridge’s gird­ers was “in­ac­cu­rate.” Gird­ers span the piers and form the base on which the road deck sits. The mis­cal­cu­la­tion forced a girder re­design that added “stiff­en­ers” to make them stur­dier.

Then there was the stuff that no en­gi­neer could have fore­seen.

Af­ter drilling 46-foot deep holes for the piers, Minichi found un­sta­ble rock. That re­quired drilling an­other 9 feet to reach sta­ble rock, DiPi­etro said.

Minichi also found un­sta­ble earth where the bridge abut­ments — the con­crete foun­da­tions on ei­ther end that sup­port the bridge — would go. That re­quired dig­ging deeper and ad­just­ing the bridge’s con­crete foot­ers’ construction.

Pen­nDOT also had to ac­count for un­fore­seen vi­bra­tion mon­i­tor­ing, win­ter main­te­nance, catch basin re­con­struc­tion and other lesser fac­tors.

Scran­ton Mayor Bill Cour­tright said he was un­aware of the project’s cost over­runs and the de­lay in fin­ish­ing the project. He cred­ited construction of­fi­cials with keep­ing the city aware of clo­sures dur­ing construction.

“I didn’t re­al­ize it was a year be­hind,” he said. “I know peo­ple want it open, the sooner the bet­ter.” Con­tact the writer: bkrawcze­niuk@timessham­; 570-348-9147; @Bo­rys­BlogTT on Twit­ter


Construction con­tin­ues on the Har­ri­son Av­enue Bridge in Scran­ton.


An ac­cess road used dur­ing construction of the new Har­ri­son Av­enue Bridge in Scran­ton.


Construction con­tin­ues on the Har­ri­son Av­enue Bridge in Scran­ton.

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