THE GRAND POUR

Or­ches­trat­ing the lay­ing of an am­bi­tious con­crete foun­da­tion was job of a life­time

Los Angeles Times - - WILSHIRE GRAND -

Michael March­esano gazed out the win­dow of his third-floor of­fice in down­town Los An­ge­les and didn’t like what he saw. In a far cor­ner of an ex­ca­vated pit, five sto­ries deep and the size of a city block, stood a mound of dirt as big as a small house. It wasn’t sup­posed to be there.

The week­end con­struc­tion crew, look­ing like toy fig­ures, was oc­cu­pied with other jobs: ty­ing to­gether steel re­in­forc­ing bars, string­ing poly­eth­yl­ene tub­ing, arc-weld­ing a raker beam into a lag wall.

It would be three more years be­fore the com­pleted Wil­shire Grand tower would rise 1,100 feet above the cor­ner of Figueroa Street and Wil­shire Boule­vard. With an open prom­e­nade and an enor­mous swoop of glass above the en­trance, the translu­cent air­plane wing 73 sto­ries tall promised to re­de­fine ar­chi­tec­tural pos­si­bil­i­ties in a city not known for its tall build­ings.

Be­neath its de­sign was the en­gi­neer­ing of what is ar­guably the most complicated high-rise ever built in the United States. Cal­cu­lated to sway dur­ing pow­er­ful Santa Anas and ab­sorb ground move­ment dur­ing the most se­vere earth­quakes, it is wed­ded aes­thet­i­cally and tech­ni­cally to the unique foot­print of the re­gion.

But what mat­tered in early 2014 was a pile of dirt.

March­esano, a gen­eral su­per­in­ten­dent for Turner Con­struc­tion Co., knew he had no time to haul it away. A count­down clock on the wall gave him 7 days, 11 hours, 36 min­utes, 7.8 sec­onds be­fore the start of the Grand Pour, an am­bi­tious at­tempt to lay the foun­da­tion of the build­ing’s cen­tral tower in one overnight ses­sion.

Of all the sites March­esano had worked in the course of 30 years, none had been this complicated. Nor, he sus­pected, would any be in the fu­ture.

This sky­scraper, the tallest struc­ture in the western United States, rep­re­sented a ca­reer-defin­ing mo­ment, a daunt­ing and glo­ri­ous job that had to be ap­proached one step at a time if san­ity was to pre­vail.

The dirt mound was the next step. Just off to a side, they would have to work around it un­til it could be re­moved.

Then they would be ready to re­ceive 2,120 truck­loads of con­crete in a hole 18 feet deep and nearly two-thirds the size of a foot­ball field. It had to be poured with­out in­ter­rup­tion in less than 30 hours.

Noth­ing this size had ever been recorded. In 1999, con­struc­tion of the Vene­tian in Las Ve­gas in­cluded a con­tin­u­ous pour that made the Guin­ness Book of World Records. If the Grand Pour suc­ceeded, it would be big­ger.

March­esano and his team had be­gun pre­par­ing nearly a year ear­lier: fil­ing per­mits for street clo­sures, hav­ing bus lines rerouted, or­der­ing backup equip­ment and cal­cu­lat­ing drive times.

More than 350 work­ers would be on site, and 227 trucks on the road, loop­ing from batch plants to down­town and back. Any glitch, in­jury, ac­ci­dent or free­way snarl would jeop­ar­dize the plan, and that wasn’t even tak­ing into ac­count the weather. Rain or a heat wave could force de­lays. God would weigh in on that.

For a sys­tem as finely tuned as a rocket launch, ev­ery­one banked on suc­cess, leav­ing March­esano to worry about fail­ure.

Let other sky­scrapers in other cities be built upon piles and cais­sons driven into bedrock. The foun­da­tion for the Wil­shire Grand is a con­crete slab.

Its spec­i­fi­ca­tions were drawn up by en­gi­neers who, af­ter cal­cu­lat­ing the height and weight of the tower and the forces as­so­ci­ated with earth­quakes and wind­storms, de­ter­mined that it needed to con­tain 21,200 cu­bic yards of con­crete and 7.1 mil­lion pounds of re­in­forc­ing steel.

By some cal­cu­la­tions, those in­gre­di­ents are enough to build an en­tire 10-story of­fice build­ing.

De­sign de­ci­sions are com­pro­mises driven by safety and cost. If the slab were to con­tain less con­crete and be more shal­low, it would re­quire more re­in­forc­ing steel, and if it were to con­tain less steel, it would have to ex­tend deeper into the bedrock. Eigh­teen feet was the mid­dle ground.

For a time there had been talk about lay­er­ing the foun­da­tion in two pours, each 9 feet deep. But given how dif­fi­cult it would be to con­nect the two slabs, the idea was shelved.

The num­bers for the Wil­shire Grand — in­clud­ing 900 ho­tel rooms and 400,000 square feet of of­fice space — had al­ways im­pressed March­esano, who at first was un­cer­tain whether the pour would be pos­si­ble.

To pull it off, he knew he would need to find room for all the equip­ment on an al­ready crowded site. He would also have to find a sup­plier who could make and de­liver that quan­tity of con­crete. Nei­ther was a sure thing.

Such prob­lems didn’t ex­ist in the open fields of Or­ange County where March­esano learned the con­struc­tion busi­ness in the 1980s. Af­ter grad­u­at­ing from high school in Irvine and dig­ging trenches for an un­der­ground util­ity, he turned to con­struc­tion.

He opened a de­mo­li­tion and con­crete-cut­ting com­pany that he named af­ter his wife and chil­dren, but the econ­omy turned on him. He lost his home. His mother died. His fa­ther had a stroke, and he and his wife split up.

Leav­ing the state in 1990, he found work on a cattle ranch in Colorado, earned the nick­name “Hol­ly­wood” and moved up from clean­ing feed troughs to rid­ing and doc­tor­ing the herd. A year later, a phone call brought him back to Or­ange County to work for a lo­cal builder. He rented an apart­ment on Bal­boa Is­land where he lived with his three chil­dren, and he even­tu­ally re­mar­ried.

He joined Turner in 1999 and su­per­vised the con­struc­tion of such projects as Dis­ney’s Grand Cal­i­for­nian Ho­tel and the Ter­ranea Re-

sort in Ran­cho Pa­los Verdes.

Above his desk, he keeps a pho­to­graph from one of his first jobs, al­most 25 years ago.

Back to the cam­era, he stands look­ing at a two-story tilt-up that has just been raised in Foun­tain Val­ley, the pre­fab con­crete wall held up with braces. “I’ll never for­get that mo­ment,” he said.

In the Turner of­fices in 2014, schematic draw­ings and cross-sec­tions of the sky­scraper were hung next to sketches scrib­bled on walls in erasable ink. Over­head, a ban­ner read, “Com­mu­ni­ca­tion pro­motes progress,” words bor­rowed from Rick War­ren, pas­tor of Sad­dle­back Church in Or­ange County, where March­esano lives.

Mo­men­tum was crit­i­cal, March­esano said, for a build­ing whose bud­get was once set at $1 bil­lion and had al­ready risen by $750,000. Time was money for the owner of the prop­erty, Korean Air, whose par­ent com­pany, Han­jin Group, is chaired by Yang Ho Cho.

First came dis­man­tling the old Wil­shire Grand piece by piece, fol­lowed by haul­ing away about 250 truck­loads of dirt each night for nearly six months. Then March­esano had to make sure that the pour was even pos­si­ble.

He pen­ciled out the con­straints.

For one, the con­crete had to be laid within 90 min­utes of be­ing mixed; oth­er­wise it would be­gin to set and not meet the re­quire­ments for the job. Also, the work had to be com­pleted in less than three shifts; oth­er­wise the truck driv­ers would vi­o­late fed­eral reg­u­la­tions and ex­ceed their al­low­able 15 hours on the road.

As March­esano did the math, he won­dered if the site had room for the pumps needed to ferry the con­crete from mix­ing trucks into the pit. He turned to the com­puter geeks down the hall, wiz­ards at plot­ting and spin­ning in cy­berspace the foot­print of the con­struc­tion site and the sur­round­ing streets.

They found room for 19, more than enough, and cal­cu­lated their place­ment, each within a foot. Any­thing out of align­ment, and March­esano would have a safety haz­ard and traf­fic jam on his hands.

With each pump av­er­ag­ing 100 cu­bic yards an hour, the job would take ap­prox­i­mately two shifts and no more than a week­end.

March­esano found that CalPort­land Co. had eight mix­ing plants no more than a half-hour drive from down­town. He locked up the con­crete, and CalPort­land be­gan ship­ping sup­plies early: ce­ment from Mo­jave and Colton, ag­gre­gate from Ir­win­dale.

The most crit­i­cal as­pect of the pour, how­ever, would take place some 16 hours af­ter the last truck left the site.

Of­ten de­scribed as a fruit­cake, con­crete is a mix­ture of ce­ment, ag­gre­gate and, in this case, fly ash that heats up when wa­ter is added, form­ing crys­tals that lend the ma­te­rial its strength. The heat typ­i­cally dis­si­pates in most pours, but the size and the depth of this slab meant the tem­per­a­ture would in­crease over the course of nearly two weeks. If not con­trolled, it would even­tu­ally crack the crys­tal struc­ture, turning the slab into gravel.

With the help of a na­tional ex­pert in the field of con­crete ther­mo­dy­nam­ics, Turner in­stalled a ra­di­a­tor sys­tem in the foun­da­tion: a suc­ces­sion of loop­ing hoses, 90,000 feet of polypropy­lene, that would draw off the heat by cir­cu­lat­ing 40,000 gal­lons of wa­ter chilled to 45 de­grees. The hoses, even­tu­ally filled with grout, re­main in the slab.

Be­cause of con­crete’s sen­si­tiv­ity to heat, the con­struc­tion com­pany mon­i­tored long-range weather fore­casts. A heat wave — mid-80s or higher — would in­crease the tem­per­a­ture of the de­liv­ered con­crete be­yond the ca­pa­bil­ity of the chill­ing sys­tem.

As the count­down clock ap­proached zero, me­chan­ics and sup­ply trucks were poised to re­pair the con­crete pumps if any failed. An in­fir­mary was staffed, and tarps and tents were stock­piled in case of rain. The out­side tem­per­a­ture was within mar­gins.

At that point, only a light­ning storm would de­lay the pour. The booms, angling into the pit, could serve as con­duc­tors.

By late af­ter­noon on Feb. 15, un­der clear skies and with tem­per­a­tures drop­ping from a high of 78 de­grees, the con­voy of mix­ing trucks had fol­lowed their in­struc­tions: Exit the 110 Free­way at 6th Street and ei­ther con­tinue to Flower and turn right on 7th, or turn on Figueroa, be­fore be­ing di­rected to the site.

At 4:47, af­ter the VIPs had fin­ished their speeches and with the USC march­ing band play­ing, con­crete be­gan flow­ing into the for­est of re­in­forc­ing steel.

Through­out the night, pumps fed the mix through booms, an­gled like scor­pion tails from the road down to the hole.

Crews stood on top of the for­est and with long, snake-like vi­bra­tors dis­persed the mix­ture as it flowed from the booms through the trem­ies, flex­i­ble noz­zles shaped like ele­phant trunks that de­posited the slurry into the bot­tom of the pit.

When the last of the con­crete reached the pit at 11:30 Sun­day morn­ing, the slab mea­sured 17 feet, 7 inches deep. The re­main­ing five inches would be added at a later date to pro­vide a more pol­ished look.

The par­ti­cles of ce­ment, fly ash and wa­ter be­gan to crys­tal­lize. Long chains of cal­cium sil­i­cate hy­drate filled the spa­ces be­tween the sand and ag­gre­gate, and for the next two weeks, sen­sors would record the in­creas­ing tem­per­a­tures in the slab.

They var­ied by as much as 35 de­grees through­out the foun­da­tion, an ac­cept­able dif­fer­ence, with some reach­ing 158 de­grees, two de­grees shy of the limit.

John Ga­jda, the ex­pert in ther­mo­dy­nam­ics, was sat­is­fied. “It was a lo­gis­ti­cal night­mare,” he said after­ward. “I would call it a dance, but it was re­ally a bal­let.”

An ad­ju­di­ca­tor from Guin­ness World Records con­firmed the ac­com­plish­ment.

Turner Con­struc­tion Co. had beat the Vene­tian for the largest con­tin­u­ous pour by 200 cu­bic yards, enough to lay a sub­ur­ban side­walk for al­most a mile.

March­esano al­lowed him­self a mo­ment of re­flec­tion. “How could you not want to be part of this?” he asked, think­ing back to the photo on his desk. “It beats do­ing a tiltup.” Then he be­gan look­ing ahead. He needed to start build­ing a plat­form on top of the con­crete for crews to as­sem­ble a climb­ing sys­tem that would start pour­ing the con­crete tower.

And now he could get rid of that mound of dirt.

Mel Mel­con Los An­ge­les Times

MICHAEL MARCH­ESANO, left, gen­eral su­per­in­ten­dent, and Bill Depasquale, field op­er­a­tions su­per­in­ten­dent, on the foun­da­tion. “How could you not want to be part of this?” March­esano asks.

Pho­to­graphs by Mel Mel­con Los An­ge­les Times

TRUCKS DUMP their loads into pumps that send con­crete through booms into the foun­da­tion. The trucks’ po­si­tions were plot­ted to the foot to en­sure room.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.