CLT PROJECT SPURS NEW EQUIP­MENT DE­SIGN

Australasian Timber - - FRONT PAGE -

THE JOHN­SON fam­ily op­er­ates a lum­ber mill and a glu­lam plant in the Pa­cific North­west re­gion of the US, and wanted to ex­pand their prod­uct line to in­clude cross­lam­i­nated tim­bers. They tapped USNR for a so­lu­tion. The re­sult is a unique mod­u­lar CLT press that is meet­ing their needs to­day, and can be ex­panded to meet fu­ture needs.

The John­son fam­ily has been in the wood prod­ucts busi­ness in Ore­gon for over 50 years. Va­lerie John­son and her sis­ter Jodie West­brook are sec­ond­gen­er­a­tion own­ers of the busi­ness and are in­volved in the day-to-day op­er­a­tions.

The com­pany owns and op­er­ates three plants. Um­pqua Lum­ber is lo­cated at Rose­burg. The com­pany’s main­stay, D.R. John­son, is lo­cated at Rid­dle, where the com­pany was founded in 1951. Rid­dle Lam­i­na­tors was added on the same site at Rid­dle in 1967.

The mills pro­duce di­men­sion lum­ber, struc­tural joists, planks, lam­i­nated beams, util­ity poles (up to 135 feet), and their lat­est prod­uct is cross-lam­i­nated tim­bers, or CLTs. Rid­dle Lam­i­na­tors was built to man­u­fac­ture glue-lam­i­nated beams. Go­ing for­ward, both the glu­lam beams and the cross-lam­i­nated tim­ber pan­els will be pro­duced and sold un­der the name D.R. John­son.

While CLT has been pro­duced and used in struc­tural projects in Europe for about 20 years, D.R. John­son has re­ceived the first U.S. cer­ti­fi­ca­tion to man­u­fac­ture the pan­els un­der a new stan­dard ap­proved last year by the Amer­i­can Na­tional Stan­dards In­sti­tute (ANSI) (PRG 320-2012). The com­pany’s prod­ucts were tested and cer­ti­fied by the En­gi­neered Wood As­so­ci­a­tion (APA).

Revo­lu­tion­is­ing the use of tim­ber in con­struc­tion

“This is not merely a new en­gi­neered com­pos­ite panel prod­uct,” Lech Muszyn­ski, a pro­fes­sor in the OSU Depart­ment of Wood Sci­ence and Engi­neer­ing, said in a news re­lease. “It’s an en­tirely new build­ing tech­nol­ogy that is revo­lu­tion­is­ing the use of tim­ber in con­struc­tion and dra­mat­i­cally cut­ting the over­all time for con­struc­tion projects.”

The cer­ti­fi­ca­tion paves the way for D.R. John­son to mar­ket its 3-lam, 5-lam, and 7-lam CLT pan­els to an emerg­ing U.S. wood build­ing mar­ket. CLTs are en­gi­neered wood pan­els typ­i­cally con­sist­ing of three, five or seven lay­ers of di­men­sion lum­ber ori­ented at right an­gles to one an­other and then glued to form struc­tural pan­els with ex­cep­tional strength, di­men­sional sta­bil­ity and rigid­ity. The max­i­mum panel size cur­rently pro­duced is 10’ x 24’ x3, 5, or 7 lay­ers.

These pan­els are com­po­nents of a con­struc­tion sys­tem com­monly re­ferred to as “Mass tim­ber con­struc­tion,” a re­vival of build­ing taller build­ings with wood, greatly re­duc­ing the car­bon foot­print of the project. These build­ings have high seis­mic re­silience, and although it’s counter-in­tu­itive, a bet­ter fire re­sis­tance than steel. It is also pos­si­ble to com­bine CLT with other build­ing ma­te­ri­als in a hy­brid sys­tem.

D.R. John­son first got in­volved with CLT in re­sponse to a plea for test pan­els from Thomas Maness, Dean of the Col­lege of Forestry and Di­rec­tor of the Ore­gon For­est Re­search Lab­o­ra­tory. He had or­ga­nized an in­dus­try meet­ing in which Univer­sity re­searchers, Mass tim­ber ar­chi­tects, and in­dus­try pro­duc­ers came to­gether to dis­cuss the mar­ket po­ten­tials of CLT.

“They put on an amaz­ing pre­sen­ta­tion to around 40 in­dus­try CEOs,” Va­lerie John­son re­mem­bered. “It was ex­cit­ing and looked like an amaz­ing op­por­tu­nity.” The aca­demic re­search group was look­ing for in­dus­try sup­port to help kick start the pro­duc­tion of CLT in the Pa­cific North West. The re­searchers just needed some test pan­els to get the process go­ing.

Hav­ing op­er­ated a glu­lam plant for many years, Va­lerie was con­fi­dent that her team could fig­ure it out. “Sev­eral of our peo­ple have PhDs in com­mon sense,” she quipped. Un­der the keen eye of John Red­field, COO of D.R. John­son, the com­pany made 15 test pan­els that were eval­u­ated and tested by APA against spe­cific cri­te­ria

in­clud­ing struc­tural per­for­mance, de­sign prop­er­ties, and ap­pear­ance clas­si­fi­ca­tions. A set of stan­dards was is­sued by ANSI to the in­dus­try, and D.R. John­son re­ceived of­fi­cial cer­ti­fi­ca­tion to pro­duce CLT. “It’s a real big deal” Va­lerie ex­claimed, “and the fact that a US man­u­fac­turer is a ma­jor col­lab­o­ra­tor makes it a big story.”

Unique ma­chine de­sign

USNR was com­mis­sioned to de­sign and man­u­fac­ture D.R. John­son’s CLT press. USNR is ac­cus­tomed to pro­duc­ing presses for the man­u­fac­ture of OSB, MDF, and ply­wood, but this is the com­pany’s first press for the man­u­fac­ture of cross lam­i­nated tim­bers, and it’s a dif­fer­ent an­i­mal al­to­gether.

But the mill had the cart be­fore the horse. D.R. John­son was get­ting ready to break ground in Rid­dle, and USNR had al­ready be­gun man­u­fac­tur­ing the press plates when some­body sug­gested that John Red­field take a team to Europe to in­ves­ti­gate the pro­cesses of a more ma­ture mar­ket. They took the trip and con­firmed the Euro­pean presses looked a lot like USNR’s de­sign. But there are some key dif­fer­ences.

One dif­fer­ence is the use of com­pressed air in­stead of hy­draulics. USNR’s CLT press uses pneu­matic pres­sure to pro­duce 10’ wide CLT pan­els up to 24’ long and 10.5” thick. The pan­els are as­sem­bled us­ing be­tween three to seven lay­ers of cross-laid tim­bers. Ad­he­sive is ap­plied be­tween the lay­ers prior to the panel en­ter­ing the press.

This press fol­lows a “win­dow frame” de­sign con­sist­ing of 16 iden­ti­cal steel frames spaced 18” apart, with each frame hav­ing an open­ing (or “win­dow”) which al­lows CLT pan­els to pass through the press. Once the panel has been fed into the press via a set of pop-up rolls, it comes to rest on platens within the press open­ing.

A set of pneu­matic cylin­ders then ap­plies pres­sure from the sides to en­sure min­i­mal gap be­tween tim­bers within a given layer. Mean­while, a set of chan­nels car­ry­ing 8 large di­am­e­ter pneu­matic hoses is low­ered to rest on top of the CLT panel. Once the panel is con­fig­ured cor­rectly within the win­dow of the press, the 8 hoses are brought to pres­sure (typ­i­cally to 100 psi, though it’s ca­pa­ble of de­liv­er­ing up to 150 psi of pres­sure). Press time de­pends largely on the time it takes to lay-up the panel, with a ra­tio of ap­prox­i­mately 2.5:1 (press time to layup time).

The unique cur­va­ture of USNR’s press open­ing al­lows it to re­dis­tribute stress and with­stand the tremen­dous pres­sures re­quired to pro­duce APA-cer­ti­fied CLT pan­els. While most CLT presses uti­lize hy­draulic cylin­ders to achieve the nec­es­sary pres­sures, the USNR press ap­plies pres­sure pneu­mat­i­cally in­stead, thanks to a heavy-duty hose which takes ad­van­tage of re­cent ma­te­rial ad­vance­ments in the oil and gas in­dus­try.

Cost-ef­fec­tive sys­tem

This method is ro­bust, ex­tremely cost-ef­fec­tive, and more en­vi­ron­men­tally friendly than the hy­draulic al­ter­na­tive. An ad­di­tional ad­van­tage to the USNR de­sign is its mod­u­lar­ity – although the press is cur­rently con­fig­ured to pro­duce 24’ pan­els, it could eas­ily be mod­i­fied to any de­sired length by sim­ply adding or re­mov­ing win­dow frame seg­ments.

“The real ge­nius of USNR’s de­sign is putting the win­dow frames in 18-inch in­cre­ments,” Va­lerie said. USNR’s mod­u­lar press de­sign en­ables it to be ex­panded in­fin­itely along its length, giv­ing D.R. John­son the flex­i­bil­ity to grow their press.

“If USNR had not come up with that, I don’t know if we would have ever pulled the trig­ger be­cause we didn’t know ex­actly what we needed at the time,” she re­mem­bered. “We started out want­ing to make an 8 x 16’ panel, then it went up to 10 x 16’, and over time we fi­nally set­tled on 10 x 24’. The fact that USNR de­signed it with frames that could be added in a mod­u­lar way is sheer ge­nius. It was the an­swer for us.” Laura Meeker, USNR Me­chan­i­cal En­gi­neer on the project ex­plained, “The mod­u­lar­ity evolved from the fact that the project be­gan with a smaller press, and when we re­al­ized they needed a big­ger press, it seemed like a nat­u­ral so­lu­tion.”

Mar­ket out­look

The out­look is bright for D.R John­son’s CLT prod­uct with sev­eral jobs in the pipe­line. “The mar­ket fo r CLT is grow­ing,” said Va­lerie. “We are ei­ther un­der con­tract or in de­sign con­ver­sa­tions for over a dozen projects along the West Coast. De­mand is there, and we ex­pect other man­u­fac­tur­ers to en­ter the mar­ket soon. Competition would give the mar­ket more con­fi­dence and it would make more sup­ply avail­able.”

D.R. John­son is cur­rently man­u­fac­tur­ing CLT pan­els for the Richard Wood­cock Ed­u­ca­tion Cen­tre at Western Ore­gon Univer­sity. Western Ore­gon Univer­sity was the first project to con­tract with D.R. John­son and pro­vided the mo­men­tum to build the CLT plant and press. The com­pany is also man­u­fac­tur­ing CLT for a mixe­duse build­ing in North Port­land be­ing de­vel­oped by the Al­bina Yard Project.

In ad­di­tion to those projects, the com­pany is in de­sign con­sul­ta­tions with many other West Coast de­vel­op­ers. Com­bined, the con­tracted work and project pipe­line rep­re­sents nearly a half-mil­lion square feet of CLT pan­els that may re­quire adding an ad­di­tional la­bor shift for the Rid­dle plant.

“Re­sponse to the prod­uct has been very pos­i­tive,” Va­lerie said. “This re­ac­tion from the mar­ket is show­ing there are projects ready to de­sign with CLTs. Hav­ing a source now where the prod­uct can be bought will help build the mar­ket for it.”

Va­lerie said the pan­els can be de­liv­ered to con­struc­tion sites with win­dows and doors pre-cut. She also noted the com­pany will be in­stalling a Hun­deg­ger 5-axis CNC com­put­eraided panel fab­ri­ca­tor early this year. That ad­di­tion will pro­vide the abil­ity to cus­tom­ize each CLT panel with pre­cise rout­ing and cut­ting based on the project’s com­puter-aided de­sign (CAD) files, which can in­clude elec­tri­cal and plumb­ing.

The customization of pan­els to pre­cise spec­i­fi­ca­tions will fur­ther re­duce con­struc­tion time­lines and costs. D.R. John­son ex­pects the mar­ket to re­quire this level of pre­fab­ri­ca­tion be­cause there isn’t an eco­nom­i­cal way to move these pan­els around on the job­site to do this work. A 10 x 24’ panel of 5-ply weighs al­most 5,000 lbs.

How does it com­pare?

One of the big­gest ways CLT beats con­crete, steel and other al­ter­na­tives is that it as­sem­bles like a Lego set. The ma­te­rial is lighter and eas­ier to han­dle. In ad­di­tion, there are a lot less trades on a CLT job­site com­pared to those us­ing ma­te­ri­als that re­quire a va­ri­ety of ex­pen­sive trades­men. CLT doesn’t re­quire the skilled man­power or the time. It can ba­si­cally be con­structed with a crane op­er­a­tor and some­one to han­dle a screw gun.

But it puts a lot of pres­sure on the mill to get the stag­ing and de­liv­ery right. If you can imag­ine a 4-storey build­ing con­structed with CLT, they will lit­er­ally have to keep track of where ev­ery panel goes in the con­struc­tion process. The first truck that leaves the mill should have the first panel needed on the top of the load. It has to be se­quenced ex­actly so they can lift that panel off the truck and put it right into place. They don’t want to be stack­ing them on the job­site.

Pro­mo­tional ma­te­ri­als on the CLT pan­els em­pha­size that the prod­uct re­duces the car­bon foot­print of a project, has high seis­mic re­silience and com­pa­ra­ble fire re­sis­tance to steel. Fire is a ma­jor con­cern, and one rea­son no doubt, that codes have lim­ited the height of wooden struc­tures. But solid CLT pan­els do not ig­nite as eas­ily as 2 x 4s. Even if pan­els do burn, char­ring on the out­side pro­tects the in­te­rior wood, leav­ing the panel struc­turally sound. Fin­ish­ing the pan­els with wall­board or an­other ma­te­rial fur­ther im­proves fire pro­tec­tion.

In Europe, cross-lam­i­nated tim­ber has been around long enough that stan­dards for fire pro­tec­tion and acous­tics are be­ing in­cor­po­rated into build­ing codes. In North Amer­ica, a more ba­sic un­der­stand­ing of the prod­uct is needed first.

Va­lerie says that con­trac­tors are cur­rently fa­mil­iar­iz­ing them­selves with cross-lam­i­nated tim­bers. Build­ing with CLT pan­els brings a learn­ing curve that re­quires ad­just­ments to the tra­di­tional bid­ding process and build­ing meth­ods, since the in­stal­la­tion process is as new as the prod­uct it­self. Va­lerie sug­gests that aca­demics and govern­ment of­fi­cials ar­range classes and sem­i­nars where con­trac­tors, en­gi­neers and ar­chi­tects can learn how to work with CLT.

“There were a num­ber of things that fell into place for us to make this a re­al­ity,” Va­lerie said, “but with­out USNR we’d be nowhere yet.”

The new CLT press at D.R. John­son uses a mod­u­lar win­dow frame de­sign that can be ex­panded to ac­com­mo­date the needs of the mar­ket.

*A glu­lam beam at D.R. John­son un­der com­pres­sion. The com­pany uses a USNR Mann Rus­sell RF Glu­ing ma­chine to cure the glue in large beams and fin­ger-joint stock.

Laura Meeker (left), USNR Me­chan­i­cal En­gi­neer and Va­lerie John­son, Pres­i­dent of D.R. John­son stand by a 5-ply CLT panel pro­duced on the mills’ new press.

A worker man­u­ally lays up a 5-ply CLT panel just prior to load­ing in the press. The panel con­sists of di­men­sion lum­ber ori­ented at right an­gles to each other and then glued to form struc­tural pan­els with ex­cep­tional strength, di­men­sional sta­bil­ity, and rigid­ity. Up­date: DR John­son has since in­stalled a lay-up ma­chine to au­to­mate the lay-up process. This in­creases pro­duc­tion ca­pac­ity, al­low­ing the plant to meet in­creas­ing mar­ket po­ten­tial.

Close-up of a 5-ply CLT panel. A 10 x 24’ panel of 5-ply weighs al­most 5,000 lbs.

The 5-ply CLT panel be­ing cured in the USNR press.

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.