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Gaining the Benefits of Structural Steel P A R

K I N G

G A R A G E S

PARKING STRUCTURE

CASE STUDIES

There’s always a solution in steel.



T h e r e ’ s

a l w a y s a

s o l u t i o n

i n

s t e e l .

American Institute of Steel Constructi

www.aisc.org

One East Wacker Drive Suite 700

Chicago, IL 60601

312.670.2400

Printed on recycled paper.

Structural steel as a framing system for open-deck parking structures?

When the AISC first represented the structural steel industry at the International

Parking Institute Conference and Exhibition in 2001 that question was often asked.

Structural steel framing systems for open-deck parking structures were not common

and many parking professionals had never even considered structural steel as a

framing system alternative.

There were some areas around the country where structural steel-framed parking

structures were being constructed. Post-tensioned decks on structural steel frames

had been used successfully in the Pittsburgh area for several decades. Over the

previous 10 years hybrid systems utilizing pre-cast double tees on steel frames had

grown in popularity in New York City and New England. But the majority of parking

professionals throughout the U.S. knew little of steel-framed systems.

What a difference seven years makes. Today, structural steel-framed parking

structures are being built in all parts of the country. The market share of steel-framed

parking structures has quadrupled. Owners and developers are actively investigating

steel as a framing system and discovering the multitude of advantages that steel

brings to the table—cost savings, accelerated construction schedules, quality,

security, and sustainable construction. Structural steel leads all other materials in

recycled content and conservation of natural resources.

And the conversations at conferences and exhibitions have changed. The quizzical

looks have been replaced by “how to” questions and discussions of recent projects

completed with structural steel.

I hope you will take a few minutes and read through the case studies in this booklet.

They truly document the successes that have been experienced when structural steel

becomes the material of choice for parking structures.

John Cross

Vice President



MODERN STEEL CONSTRUCTION 3

As the city of Lewiston, ME

planned construction of its700-space Park Street park-ing structure, aesthetics, aswell as cost and the ability

to be built in phases, were major designconsiderations.

Located 30 miles north of Portland,ME, Lewiston was once a mill town. Likemany other mill towns, its downtownsuffered as the mills closed. Renovationof a vacant downtown building for useas a district courthouse was seen as a po-tential boon to the area’s comeback. Themaster plan identified a two-acre surface

parking lot as the site for a new parkingstructure, as well as an incorporated city bus station, for the courthouse and otherexpected development.

Because few of the downtown buildingsare over four stories high, skeptics worriedthat a new structure would overwhelmthe surrounding buildings. In response tothese worries, the RFP for design servicesspecified that the structure be designedwith a “brick façade treatment” to make itmore compatible with its surroundings.

Steel’s Advantage

Platz Associates architects and Shel-ley Engineering, Inc. structural engineershad worked together on many previousprojects, including Lewiston’s 612-spaceChestnut Street steel-framed parkingstructure. The overriding criterion for theChestnut Street project was cost, which iswhy structural steel was chosen over pre-cast concrete.

Cost was also a major considerationfor the Park Street facility. The city’s bud-get precluded a brick closed structure,which increased the challenge of design-ing a facility that would meet the city’s

stated design goals. It was also decidedto build the structure in two phases, asthe projected parking demand would notimmediately require all 700 spaces thatwere programmed for full build-out.

From its experience with the ChestnutStreet parking structure, the design teamknew the advantages of structural steel.In addition to initial cost being less thanother structural systems, maintenancecosts could be reduced with proper plan-ning at the construction stage. Building a

second vertical stage could be easily ac-

complished when the need arose, and theuse of ornamental panels could providea great deal of design possibilities. Thedesign team was also confident that theexpressiveness of painted structural steelcould add visual interest to the city.

A city-appointed building commit-tee called for the structure’s perimeterwalls to look like storefronts. By takingadvantage of the flexibility afforded bystructural steel, the designers were ableto simulate the rhythm of a downtownstreetscape within budget. Vehicular andpedestrian entrances, stair towers, arch-

es, and ornamental panels were hung between the steel columns. Some of thesepanels are pre-cast to provide the textureof brick, while others are steel grills ofseveral different patterns. This was meantto break up the façade into distinct verti-cal sections. With different heights, thesesections reflect the scale and proportionsof neighboring buildings.

The northeast corner of the facility isanchored by a 2,400 sq. ft city bus station.Although they are two distinct buildings,

Affordable AestheticsBy Steve Myers

Steel provided necessary flexibility in construction and aesthetics for

this 700-space parking structure in Lewiston, ME.

JUNE 2005 MODERN STEEL CONSTRUCTION

3



separated by a load bearing masonry fire-wall, the bus station is integrated into thedesign of the parking structure both visu-ally and structurally. It is constructed ofthe same structural steel system, which isexposed as a design element in the inte-rior. The lower portion of the perimeterwalls is brick, a tie-in to the ornamentalpanels of the parking structure. The inte-

gration of these two buildings is anotherindication of structural steel’s flexibility.

Framing PlansThe basic framing arrangement for the

three-level parking structure consists ofwide-flange columns spaced 18’ on cen-ter, with wide-flange girders spanning60’. Filler beams span the girders at 8’ oncenter. The perimeter spandrel beams areall W12s, giving the structure a light andairy feel.

Shelley Engineering designed all steelconnections in advance of the shop draw-ings. Connections, such as shear tabs atthe filler beams, were selected over dou-

ble-angle clips so that when each filler beam was rotated into place it would notscratch the paint on the girder.

The lateral system consists of end platemoment connections and vertical braces.

The engineer and architect coordinatedtheir design work to detail and locate allconnections between the perimeter orna-mental steel and the structural steel. Thetypical note, “coordinate with architect,”was not used on this project. The coordi-nation was done up front, which was re-flected in the results—the steel fit-up wasnearly perfect, with all field connections

being bolted.Megquier & Jones, an AISC member

and the project’s steel fabricator, workedclosely with the architectural pre-castpanel subcontractor to ensure the con-nections between the structural steel andpre-cast panels would fit up correctly. By

bringing the pre-cast subcontractor intothe process early, misalignment and fieldwelding were avoided, which reducedthe need for field touch up of the paint.The structural and ornamental steel wasprotected with Tnemec’s advanced Se-ries 73 polyurethane paint system overTnemec’s 90-97 zinc primer. The paintwas factory applied with minimal on-sitetouch up.

The floors of the parking structure aregalvanized metal deck with cast-in-place6” reinforced concrete slab. To reducelong-term maintenance costs, an elastic

wear layer was applied to the entire sur-face, and the deck is vented to allow theconcrete to release moisture.

The Park Street parking structure wascompleted August 2003 at a per-spaceconstruction cost of $8,350. Not only didit meet the city’s strict budget and pro-vide necessary parking, it also has madea positive contribution to the cityscape of

Lewiston’s downtown.

Steve Myers is a development planner forPlatz Associates.

OwnerCity of Lewiston, ME

ArchitectPlatz Associates, Auburn, ME

Structural EngineerShelley Engineering, Inc., Westbrook, ME

Engineering SoftwareRAM Structural System

FabricatorMegquier & Jones, Inc.,

South Portland, ME, AISC member

General ContractorGranger Northern, Inc., Portland, ME

4 MODERN STEEL CONSTRUCTION JUNE 2005




parking structures

GGIVEN THE STATE OF RISING COSTSFOR CONCRETE CONSTRUCTIONMATERIALS, protracted delivery schedulesor precast, and shrinking maintenance bud-gets, many owners are requesting a viablealternative parking structure design. Steel issuch an alternative and although surroundedby many misconceptions, its strengths posi-

tion it as a long-term solution.For a number o qualitative peror-

mance-related reasons, steel—and inparticular hot-dip galvanized steel—isa good choice or many parking struc-tures. Here are my top 10 reasons youshould consider a galvanized steel park-ing structure:

1Galvanized steel has demonstrated a ver-ifable durability or decades in a variety o environments, including coastal andindustrial. Learn more in the SteelWisearticle “Are You Next” in the September

2006 issue o MSC at www.modern-steel.com .

2Castellated beams oten used in steeldesign create an open and light-flledatmosphere where patrons eel saer.

3Galvanized reinorcing steel in decksmeans no unsightly spalling and no cor-roding seams between deck panels.

4Steel garage construction schedules areshorter.

5Galvanizing o 60-t to 80-t girders isnow common, accommodating almostall designs. The actual turnaround timeto galvanize is usually less than fve working days.

6Steel designs are overall lighter in weight, meaning ewer and/or smallercaissons.

7Galvanized coatings are aesthetically appealing not only or the structuralmembers, but also or stairways, exte-rior mesh panels, and guardrails.

8Painting structural steel means costly,scheduled maintenance and lost rev-enue. Galvanized steel is maintenance-ree or 50–80 years.

9Lie-cycle costs o galvanized steelrame parking structures are two tothree times less than precast. Lie-cycle

costs o galvanized steel rames are twoto fve times less than painted structuralsteel rames.

10Galvanized steel raming is initially 10%–20% less expensive than pre-

cast construction.

Initial CostOnce the qualitative analysis reveals that

a galvanized steel rame is maintenance-ree or decades and does prevent corrosionor many decades, even in harsh coastal

The BetterChoice

Galvanized

steel parking

structures

are stong

contenders in

today’s parking

market.

BY PHILIP G. RAHRIG

climates, the owner’s next step in the deci-sion process is to develop the quantitativeanalysis and evaluate exact initial costs. Thetable on the next page illustrates the cost o hot-dip galvanized rame design comparedto precast concrete design.

Life-Cycle Cost

Even though the initial cost o galva-nized steel is avorable to precast concrete,responsible design requires the investigationo other coatings to protect the steel romcorrosion. Although not necessarily the case, various paints are generally viewed as ini-tially less expensive than hot-dip galvanizing,and while initial cost is oten the decisiveactor when selecting a corrosion protectionsystem or steel a garage, there are othercosts that dwar this initial unding outlay.

Those costs are associated with a series o scheduled maintenance costs necessary to

protect the steel rom corrosion over theplanned service lie. For maximum protec-tion o the asset, plans should be based on anideal maintenance cycle. For paint systemsan ideal cycle calls or touch up, mainte-nance painting, and ull-repainting prior to

visual evidence o substrate steel corrosion.However, on most projects a practical, lessrigorous cycle is used, and this means main-tenance is conducted when the coating hasdeteriorated to the point where the projectlooks to be in disrepair and iron oxide (rust)

APRIL 2008



6 MODERN STEEL CONSTRUCTION

structural sections, and alkyds may be thestandard o past projects. But once the feldis narrowed to a couple o optimal coatingsystems according to desired perormance, itis important to use all the fnancial tools andmodels available to quantiy uture costs asaccurately as possible, especially with main-tenance budgets shrinking and substantiallong-term costs.

One tool is the Lie-Cycle Cost (LCC)Calculator now available at www.galvaniz-ingcost.com . As the URL implies, this site

will compare the initial and lie-cycle costs orover thirty (one-, two-, or three-coat) paintsystems to hot-dip galvanizing. A uniqueeature o the sotware is that it allows theuser to customize the input to ft his/her par-ticular project exactly. Input variables includetotal size in tons or square eet, surace prep-aration type, structural steel component size(small, medium, large), and planned servicelie o the project. The calculator allows theuser to input in either metric or U.S. units.

The primary driver and input variableo the lie-cycle cost calculation is the cor-rosion data or the project’s environmen-tal location. I a parking structure is in arural area, corrosion rates are low becauseo lower corrosive elements in the air. Fora garage in an industrial area, aggressivecorrosion may be initiated by sulfde andchloride emissions rom production plants,including high levels o automobile/truck exhaust. There are our input options orthe environment and all correspond to cat-egories described in ISO 12944-2 “Classif-

cation o Environments.” The fnancial component o the LCC

Calculator is also customizable and basedon standard net uture value (NFV) and netpresent value (NPV) calculations where thetime value o money is considered. The userselects what rate o ination is projected overthe lie o the project in order to determinethe value o money at each maintenancetime, and the average interest rate utureexpenditures on maintenance could earn—i.e., lost opportunity cost. Both are used tocalculate the more easily understood and

meaningul average annual equivalent cost(AEAC) or each coating system being mod-eled or any specifc project.

NFV = initial cost[(1+i )n}, where i = ina-tion; n = project lie in years

NPV = NFV[1/(1+i )n], where i = interestrate; n = project lie in years

AEAC = NPV[ i (1+i )n /(1+i )n – 1], where i =interest rate; n = project lie in years

is visibly evident. For a hot-dip galvanizedcorrosion protection system, maintenance isnormally not required.

To determine the timing o practicalmaintenance, most paint coating systemshave been tested in a laboratory using accel-

erated corrosion mechanisms. To be sure, i the testing indicates that a touch-up paint-ing should be perormed in year eight, amaintenance paint applied in year 13, and aull repaint in year 18, the actual project may require maintenance according to the wear

and tear on the project and the toll environ-mental corrosive elements have taken. Thatmay mean earlier-than-planned mainte-nance based on the accelerated testing.

Comparing one system to another canbe an arduous number-crunching exer-

cise urther complicated by the variousperormance characteristics each coatingsystem provides. A three-coat inorganiczinc-epoxy-polyurethane system may haveinitial durability, while hot-dip galvanizingprovides corrosion protection inside hollow

Comparison of Initial Costs

CityConcrete Cost1

($/sq. ft.)Concrete Cost2

($/sq. ft.)HDG Cost Range3

($/sq. ft.)

Atlanta 33.85 37.77 28.65 – 32.23

Baltimore 37.21 42.04 31.70 – 35.66

Boston 46.28 48.84 38.05 – 42.80

Charlotte not available 32.32 25.86 – 29.09

Chicago 43.43 47.19 36.25 – 40.78

Cleveland 40.34 42.42 33.10 – 37.24Denver 38.14 40.48 31.45 – 35.38

Dallas 33.68 35.66 27.74 – 31.20

Detroit 42.11 45.33 34.98 – 39.35

Kansas City 41.30 43.73 34.01 – 38.26

Los Angeles 42.91 45.12 35.21 – 39.61

Miami 34.81 36.59 28.56 – 32.13

Minneapolis 45.03 47.40 36.97 – 41.59

New Orleans 34.73 36.50 28.49 – 32.05

New York 52.49 55.73 43.29 – 48.70

Philadelphia 45.83 48.33 37.66 – 42.37

Pittsburgh 39.05 42.33 32.55 – 36.62

St. Louis 41.68 43.22 33.96 – 38.21

San Francisco 48.84 51.42 40.10 – 45.12

Seattle 41.74 44.02 34.30 – 38.59

National Average 41.23 42.25 33.39 – 37.57

1RSMeans, Reed Construction Data2Parking Structure Cost Outlook for 2007 - “An Inconvenient Truth,” Joey D. Rowland, P.E.3American Institute of Steel Construction - estimate

APRIL 2008




The Delaney Square parking structure inOrlando, Fla. features a galvanized steelframe.

The inormation on the cost o eachpaint system and its practical servicesequence in years or each o the ISOenvironments is contained in a database.*Based on the user’s selection o a particu-lar coating system, the sotware accessesthe appropriate feld and incorporates thedata into the lie-cycle calculation. Thereare two options or the cost inormation o

hot-dip galvanizing, also resident in a data-base. The user may either select the deault, which is a U.S. average cost, or input any number in dollars per lb or dollars per kg,based on local market inormation.

Output o the LCC Calculator includesa printable summary o all selected input as

well as tables containing the initial, NPV,total project, and AEAC or the coating

system and hot-dip galvanizing. The LCCCalculator output is available in U.S. dollarsor in any country’s currency. The currency conversion is real-time, making the LCCCalculator useul or export/import projects.

Philip G. Rahrig is the executive director of

the American Galvanizers Association.

The text of this article originally appeared in The Parking Proessional (November

2007).

Note*NACE Paper #06318, “Expected Service Lie and

Cost Considerations or Maintenance and NewConstruction Protective Coating Work,” Helsel, Melampy, & Wissmar, KTA-Tator, Inc. 2006.

APRIL 2008



8 MODERN STEEL CONSTRUCTION MAY 2006

Station Place Garage is an integral part of amixed-use development in downtown Port-land, Ore. The 149,670 sq. ft parking struc-

ture provides space for 413 vehicles on five park-

ing levels, and the design includes the potential for1,000 sq. ft of commercial space at the ground level.

The 41,450 sq. ft, triangularly-shaped site cre-ated significant challenges. The City of Portlandrequired that all parking be located on flat floorplates—not on ramps—so the building was de-signed with flat one-way parking levels and an inte-rior two-way ramp.

During Portland’s meticulous design review pro-cess, the review commission set out the followingrequirements:1. Exposed structural steel diagonal bracing was

not acceptable.2. Glare from vehicle headlights had to be screened

from view.3. Vehicles parked on the top parking level had to

be screened from the view of residents in nearbyhigh-rise residential buildings.Concrete shear walls were placed in the build-

ing’s interior to address most of the structure’s lat-eral loads. However, architects did not want to placea large concrete shear wall along the south façade,which is the most prominent of the building. Instead,exposed diagonal steel braces were designed for thelateral load, and the architect designed a full-height

JUROR COMMENT

“Transparency is the word here.”

National Winner—Less than $15M

STATION PLACE GARAGE—PORTLAND, ORE.

Richard Strode

wall of folded stainless steel plates to hide the struc-tural bracing from view.

Folded stainless steel guardrail panels withlaser-cut holes were designed around the building

perimeter to mitigate headlight glare. Four-inch di-ameter holes filled with colored discs were designedat headlight elevation. Lights from moving vehiclesilluminate the colored discs at night, animating thebuilding’s exterior. Colors vary by parking level toassist user orientation.

When viewed from above, more than 40% of thebuilding’s footprint is “green.” The atrium located onthe third parking level is 1,812 sq. ft in area and isopen to the sky. The top parking level has 2,411 sq.ft of planter space and 8,887 sq. ft of trellis, for acombined “green” area of 13,110 sq. ft.

All exposed structural steel is finished withshop-primed zinc-rich primer and field-painted with

high-performance moisture-cured polyurethane towithstand Portland’s mild climate and wet winters.

Once construction began, weekly meetings wereheld with the steel fabricator to identify and resolvepotential issues, ensuring that the preparation ofshop drawings and fabrication remained on sched-ule. The project included 1,069 tons of steel, andmore than 1,300 shop drawings were prepared.

The total construction cost was approximately $9million—around $21,910 per parking space.

OwnerPortland Development Commission,

Portland, Ore.

ArchitectLeeb Architects, LLC, Portland, Ore.

Structural EngineerKPFF Consulting Engineers, Portland,

Ore.

Engineering SoftwareRAM Structural System

SAP2000

DetailerPro Draft, Inc., Surrey, B.C., AISC mem-

ber, NISD member

Detailing SoftwareTekla Structures

FabricatorFought & Company, Inc., Tigard, Ore.,

AISC member

General ContractorAndersen Construction Company, Inc.,

Portland, Ore.




parking structures

CCHANGE IS A FACT OF LIFE, PARTICULARLY WITHLARGE, GROWING ORGANIZATIONS. To sup-port expansion and all the benefts that come with it, it’sessential to have parking acilities that can keep pace withchanging programs and use requirements. It’s also criticalto construct those acilities in a manner that maximizesconvenience and saety, minimizes maintenance costs, andleverages the ull potential o the land they’re built on.

In congested urban areas, surace parking lots are oten viewed as less-than-ideal uses or open land. As a result,multi-level parking structures are requently the preerredoption. Building an urban parking structure can, however,pose some ormidable challenges. Unlike garages built insuburban settings, urban garages must ft onto tight landparcels surrounded by existing structures. In addition, they must be constructed vertically to provide enough parkingcapacity and revenue potential to justiy the cost o con-struction. Finally, because many o the structures surround-ing parking garages typically house businesses that can’t be

disrupted or relocated during construction, every phase o construction activity must be careully coordinated.

At Ruby Memorial Hospital, the teaching hospital or West Virginia University Medical School in Morgantown, W.V., the growth o the university’s state-o-the-art cancertreatment programs demanded expansion o the parkingacility serving the hospital; the hospital’s campus had beenaugmented with the addition o a new cancer center build-ing, a structure that was built on land previously used orsurace parking adjacent to the hospital.

With real estate at a premium and the demand or park-ing growing quickly, it was essential or the hospital tomaximize the capacity o its existing parking garage. How-ever, since the parking structure was landlocked by thecancer center, other nearby hospital buildings, and the university’s ootball stadium, a horizontal expansion was outo the question. Instead, it was necessary to expand parkingcapacity within the ootprint o the existing structure, andat the same time maintain access to the hospital’s emer-

Taking it to theNext Level

Parking capacity is expanded at a growing university

hospital thanks to hybrid steel and concrete design.

BY LEN TSUPROS

APRIL 2008




gency room, which emergency vehicles accessed through the frstlevel o the garage.

Creating a Hybrid Strategy from the Ground UpSimply adding another level to the existing parking garage

was, however, not an easy task. When Carl Walker Constructiondesigned and built the original structure in 2003, the client decidednot to include oundation structures designed to accommodateuture vertical expansion. At that

point in time, the cancer treatmentacility was not yet on the drawingboard, and it was anticipated thatthe capacity o the garage wouldeectively meet the needs o thehospital or years to come. But by 2005, as the hospital was puttingthe fnal touches on its new cancercenter, it became apparent that theexisting 225-space parking struc-ture lacked the capacity necessary to support the parking volume created by the additional building.

Aware o the oundation limitations and unwilling to demolish theentire structure and start rom scratch, the hospital contacted Carl

Walker Construction. The client challenged them to revisit theoriginal designs o the building and provide a solution that wouldaccommodate the construction o another parking level that wouldprovide 105 additional spaces.

“Due to the weight considerations involved with the precaststructural components, we knew rom the outset that we couldn’tsimply add another level using the same type o structural system,”observed Len Tsupros, president o Carl Walker Construction.

“The oundations o the garage—and in particular, the network o precast beams supporting the center o the structure—were notheavy enough to handle the additional load. We needed to devise astructural system that was lighter in weight than the cast concretecomponents. We also needed to design a way to eectively attach

that structural system to the existing garage. Whatever approach we took, we knew we couldn’t do anything without signifcantly reinorcing the center supports.”

To meet the challenge, Carl Walker Construction turned to theproject’s original engineer, Charles Churches, P.E., or guidance.

Churches agreed with Tsupros that signifcant reinorcement o the structure would be needed to support the weight o the addi-tional parking level. He then worked with Tsupros and his teamto devise a reinorcement strategy that would deliver the requiredsupport and weight distribution, and to evaluate structural systemsthat could be married to the existing precast components.

Within a ew weeks, Tsupros returned to Ruby Memorial Hos-pital with a comprehensive plan that would accomplish those goals

and allow the new deck to be added

to the structure. The hybrid con-struction strategy would directly link support o a new steel-ramed, cast-in-place concrete post-tensioneddeck to the existing oundation, and would not place additional stress onthe precast columns already in placein the center o the garage. It wouldalso minimize the overall weighto the additional deck and wouldprovide a ramework to mount and

secure a series o precast panels. Those panels would seamlessly integrate with the existing building fnishes and make the post-tensioned system essentially invisible when the job was complete.

The project estimate was $2 million, or approximately $19,000 peradditional parking space.

Bringing Together Old and New Ater receiving the client’s approval on the budget and the inno-

vative design strategy, the demolition and strengthening phases o the project quickly commenced in January o 2007. Throughoutthe entire construction process, the garage remained open to hos-pital visitors, sta, and emergency vehicles.

“To install the new structural columns in the center o thegarage, we began by using a Bobcat outftted with a jackhammer tobreak through the concrete oor on the frst level between each o the eight previously installed precast columns,” remarked Tsupros.

“This allowed us to auger down, expose the grade beams that com-prised the original garage oundation, and pinpoint areas wherecast-in-place concrete columns could be directly attached to thegrade beam system.”

Once the concrete column bases were positioned on top o the

WVU’s growing medical campus prompted the need for more parking. The expansion to the garage added 105 parking spaces.

A steel-framed, post-

tensioned slab system can

be a good solution when

foundation loads are an issue.

APRIL 2008




grade beams, the construction team inserted rebar cages aroundeach junction point. Then, it backflled each cage with concrete, which owed around each grade beam and locked the columnbases into position. When the concrete had cured in and aroundthe cages, the team then poured concrete up to the oor level toclose the holes. With frm ooting in place, the team then con-structed the concrete columns that would rise through the topdeck o the precast structure, cutting through the existing decks toprovide raceways or each new column.

With the reinorcement phase o the project complete, Century Steel Erectors and Carl Walker Construction began installationo the structural steel that would orm the ramework or the newpost-tensioned parking level. The steel beams were connected tothe new cast-in-place concrete columns—shear studs are welded tothe girders—then bolted and welded in place to ensure structuralstability. At the same time, the original elevator bank was extendedup by one oor with the installation o an additional precast con-crete section that was lowered into place by crane.

When the structural steel and the elevator shat extension werecompletely installed, precast panels were trucked to the worksiteand hung on the steelwork to integrate with the appearance o the original açade. Both the steel erection and precast installationphases o the project were careully scheduled to minimize pedes-

trian and trafc obstructions, and to maintain ingress and egressrom both the garage and the hospital’s emergency department.

Lateral bracing or the new level was accomplished with theconnection to the existing precast light wall and the precast açadepanels. The panels have rods inserted at the oor level and are alsocomposite with the oor slab. This also provides or the bumperrestraint requirement at the perimeter.

Once the new precast-clad, post-tensioned structure wasinstalled, work began on constructing the steel-reinorced park-ing deck suraces. Shear studs welded to the steel members makethe new slab act compositely with the steel. The concrete slab wassupported by a temporary raming system that ft snugly betweenthe steel beams supporting the new deck. When the concretecured, the raming was removed rom the underside o the newdeck. The construction phase o the project was completed by May o 2007. One month prior to completion, cars were allowed

to park on all but the top level o the newly expanded garage.Project clean-up and punch-list items were completely addressedby August 2007.

Well-Received Results Tsupros was also pleased with his frm’s accomplishments on

this project. “This job required some out-o-the-box thinking, as well as a considerable amount o coordination between the clientand our strategic partners,” he said. “The end result, however,illustrated how marrying two dierent structural systems canexpand the capacity and liespan o existing parking structures.Our approach allowed Ruby Memorial Hospital to leverage thepotential o their original precast structure and to obtain theadditional capacity they needed to support their enhanced ser-

vice oerings.”“I would encourage anyone who currently has a precast park-

ing structure to consider the potential o a steel-ramed post-ten-sioned addition i they need additional parking capacity and areacing oundation and structural load limitations.”

Len Tsupros is president of Carl Walker Construction.

APRIL 2008



ON PARKING GARAGESINSPIRATION I’ve been interested in engineering since

I was a kid – I was always building things. My dad was

the maintenance engineer for the building we lived in

and he had this great workshop. I spent a lot of time in

there with him. And I remember when anything was

being built, I watched – I wanted to see how it wasdone. When they installed the storm sewer in the street

when I was a kid, I went down and just sat there

watching it all.

CHOICES I knew I wanted to be an engineer since I was

young. I just never knew that civil engineers did so

much. One day at school, we had a career fair and I

started talking to a guy. He was a constructionengineer. I told him the things I wanted to do and he

said, “You want to be a civil engineer.” From then on,

I knew what I wanted – to design buildings. I was 13

years old.

EDUCATION I stayed focused, graduated high school

and looked into engineering programs in the area.

Brooklyn Polytechnic offered me a scholarship to a

specialized program where I earned my bachelor’s and

graduate degrees at the same time. It was a heavy

credit load –

I was taking my grad courses during junior and senior

years. But I wanted to get into the world and find a job.

PORT AUTHORITY Working for the Port Authority was

my first job – I’ve been here 31 years. Even growing up

in Queens, I wasn’t familiar with all their facilities.

When I thought of the Port Authority, in my mind it was

the bus terminal on 42nd Street. But when I

interviewed,

I learned that they managed so many other things –

they really drive the regional economy.

INSIGHT If you look at old parking structures in New

York or New Jersey, you’ll see a lot of flat-plate

construction with cast-in-place concrete and the

resulting deterioration from corrosion. An example,

there was a parking facility that we rehabbed in 1998 at

one of our facilities with flat-plate construction. That’s

when I saw firsthand how quickly previous generations

of parking structures deteriorate. Snow and chemicals

would sit and penetrate the concrete. The shallow

covers used for parking structures allowed it to

corrode. We finally recognized that you can’t design

parking structures like you would a building. The deck

requires special protection.

PROGRESS I’ve worked on highway bridges.

The technology we began to use for bridge deck

construction 10 years ago is now used in parking

structures. A parking garage can be designed to include

the benefits of steel frames and columns using pre-cast

double-Ts. Micro-silica additives in the concrete Ts

make the deck impervious to moisture and protect the

entire structure from corrosion. We’ve found this saves

hundreds of thousands of dollars in repairs over the

lifetime of a structure – it’s a better investment.

Englot

Jo seph M. Englot, P.E., As st. C hief Engine e r/ D e sign, Po r t Au thor i t y of New Yor k and

New Je r s ey. Re spo n s ib le for 350 arc h i tect s and e ngineer s o f eve r y di sc ipline. Le ad s

the de sign an d co n st r uct ion of c ri tical tr an spor tatio n inf ras t r uc ture, f ul f illing a ll need s of

the b i- sta te re gio n’s bu sine s se s, re s ide nt s and vi si tor s. The field-exper ie nced Englo t

ove r se e s all PANY N J pr ojec t s, en sur i ng b udge t s, s che dule s and quali ty st andar d s ar e

me t.

SOIL Both the Newark Liberty and the JFK

International airports have poor soil. So we designed

the structures to be supported on steel tapered tube

piles and pile caps. These can withstand the bending

forces even if the soil liquifies in a seismic event.

Because steel is light and requires less of a foundation,it cuts the weight of the structure and is perfect for

those locations.

SEISMIC For these garages, we moved the stairwells

and elevators to the exterior and designed them to be

self-supporting in case of a seismic event. This is

unique – a lot of structures use shear walls in

stairwells. Ours use ductile steel frames and have

worked very well. Because of this, we could open the

lower floors of the garage while finishing the upper

levels and installing the elevator equipment.

OPENNESS We can use longer spans with steel – 60-

foot beams. People passing through the garage don’t

have to navigate a forest of columns. Open grid facades

replace solid pre-cast parapets. It’s more user friendly –

more open – and lets in more natural light, which

increases security. With steel, we also have fewer

columns, equating to more parking spaces. Basically,

we can utilize more of the footprint for intended use.

VALUE Although Kennedy’s Green Garage was driven by

a tight schedule, it was the basis for Newark Liberty’s

P4 Garage— and is now the standard system. But

because cost is always a tremendous concern, we

performed a value engineering analysis. The results

were great! The independent VE panel concluded that

this is the most efficient design in terms of cost per

square foot and space economy when compared to

other systems.

STEEL In 1996, we had 18 months for the

design/bid/build process for the Kennedy Green Garageand it had to fit into the location visually and

functionally. So we fast tracked the design and

concentrated on the foundation first. We issued that

package and broke ground three months later. The

design was quick to fabricate and to erect – we only

used one crane and iron workers did both jobs. It went

up so fast – it was unbelievable! We could have only

accomplished this with steel.

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866.A SK.AISC

There’s always a solution in steel.




By James Sarka, P.E.

and Roger O’Hara, P.E.

SmartBeams ® were the smart solution for this steel parking structure in Vancouver, WA.

The Legacy Salmon Creek Hos-pital campus includes two four-story medical office buildings, a1,500-car parking garage, a newhospital, and interconnecting

bridges. Construction began in May 2003.With the hospital scheduled to open for

patients in summer of 2005, this requiredoverlapping schedules for each elementof the campus. To make it work with siteconstraints and a peak employment ofover 500 craftspeople, it was essential tofast-track the 450,000 sq. ft, seven-storyparking structure to allow for parking forthe duration of the project’s construction.

Schedules and costs for the park-ing structure, designed to be primarilyabove-grade, were compared between atraditional steel frame, with long-spangirders and beams spanning 30’, andvarious concrete systems. The schedul-

ing advantage of erecting steel, especiallyduring the winter months, was a decid-ing factor in favor of a steel frame.

Design-build steel contractor R.F.Stearns, Inc. worked with Skanska USAand KPFF Consulting Engineers to pro-pose an alternate steel design usingSmartBeam cellular beams, produced bySMI Steel Products. Stearns’ history us-ing SmartBeams in long-span projectshad shown the product’s excellent appli-cation for multi-level parking structures.

In this case, the three-bay-wide struc-ture required spans of 61’-6” to 61’-9”,with floor-to-floor heights of 10’-3”. A 3”vented metal floor deck with 3.5” normalweight concrete cover provided the com-posite wear surface.

The owner and design team chose the

SmartBeams option because of the sys-tem’s positive attributes, including col-umn-free space, lighter structure weightand the corresponding decrease in lat-eral and foundation loads, fewer erectionpieces, and the reduction in overall proj-ect costs.

Exposed Steel Design ChallengesThe resulting steel system made use of

the established economic and scheduleadvantages of SmartBeams for the longspans and wide-flange braced-frames forthe lateral resistance system. KPFF was

especially attuned to the exposed natureof the garage and effectively applied thestructural design elements.

According to KPFF, special concentric braced frames in a two-story “X” config-uration were a natural choice for the ex-posed steel project. The need to have un-obstructed views inside the garage, bothfor driving sightlines and occupant safe-ty, guided the choice to place longitudi-nal frames along each side of the middleramp bay. At the contractor’s suggestion,

frames at the low end of each ramp levelwere sloped with the ramp girders inorder to eliminate difficult beam connec-tions for the adjacent level floor framing.Transverse braced frames for the garagewere placed at each exterior face of thestructure, with narrow bay widths used

to create optimum bracing geometry. Thesize and geometry of connecting gussetplates were minimized to enhance the vi-sual appearance of these exposed frames.

With long-span SmartBeams having been chosen for the floor plate, the archi-tects wanted to express the same cellularlook for the exposed perimeter girders.The challenge for the structural team wasmaintaining constant hole spacing in thecellular girders while ensuring that floor beams connected directly to web posts.The use of SmartBeam girders resulted ina cost-effective and steel weight-savings

option that eliminated the need for ex-pensive fascia treatments.

High Performance Coating SystemsOne of the many challenges with

an exposed steel project is the selec-tion of the coating system. The overalldurability and final appearance of theproject was important to the owner andarchitect. In order to meet these perfor-mance requirements, the design teamand Stearns worked together closely to

Prescription for Parking

JYLY 2005 MODERN STEEL CONSTRUCTION 13




select the proper coating system. Whileseveral options were available and evalu-ated based on an initial specification, thedecision was ultimately made to preparethe steel with an SSPC-SP10 (near white blast) surface preparation, a shop ap-plied zinc-rich primer (Sherwin-WilliamsZinc Clad II), and a field-applied epoxy

topcoat (Sherwin-Williams Macropoxy).This system was chosen due to its supe-rior performance characteristics, abilityto endure the Pacific Northwest weatherconditions, and the assurance of a consis-tent final appearance.

Glass and Steel TolerancesThe incorporation of glass and steel

components was another challenge thathad to be addressed. Glass block andcurtain wall components had to attachdirectly to the architecturally exposedsteel framework. As a result, the allow-

able tolerances for the frames had to be significantly restricted to match therequirements of the glass components.This resulted in extensive use of tightlycontrolled shop-built frames to minimizethe need for field locating the glass sup-port pieces.

It also included close coordination between Stearns, Skanska USA, and theglass subcontractor to ensure that the re-sulting steel framework would be withinacceptable tolerance for glass placement,specifically at the areas of glass blocks.The blocks were attached directly to steel

framing that consisted of WT sectionsand C-shaped bent plate sections to formthe various reveals. The resulting place-ment of the approximately 80’ tower waswithin ½” in overall plumb and square-ness. Early recognition of these issuesand close coordination between the par-ties resulted in a successful completion ofthis challenging feature.

Architectural ComponentsSeveral unique architectural features

were incorporated into the design that blended well with the exposed structuralsteel components. These items includedlandscaping panels, headlight screens,and a vehicle barrier system.

The landscape panels were custom-made grids for the incorporation ofclimbing vegetation. Panels were sup-

ported off the main building membersaround the perimeter of the building. Inorder to provide protection from directexposure to the elements, the panels re-ceived a powder-coated finish and werefield-bolted to the structure with stain-less steel fasteners.

Due to the proximity of the hospitaland the surrounding neighborhood, theowner was concerned about screeningvehicle headlights. Placement of hori-zontal and vertical steel channel sectionsabove the slab level and incorporation ofperforated aluminum panels at the north

and south sides of the building consti-tuted this screening.The vehicle barrier restraint system

consisted of 11-line, ½” diameter high-strength galvanized cables. KPFF de-signed the anchorage of these cables intothe steel structure. The resulting cablelengths allowed for a minimum numberof anchorages per floor and a less intru-sive exterior appearance for the barriersystem.

Site Conditions and ScheduleSite work and three separate buildings

were under construction concurrently atthe hospital campus, with all subcontrac-tors sharing common access for equip-ment and deliveries. The resulting sitelogistics, coupled with a tight schedule,were challenging for each of the partiesinvolved in the project. One of the mainissues involved the proper sequencingof over 150 loads of structural steel andmetal decking for the garage alone. Thisrequired daily coordination betweenStearns, Skanska USA, and the trucking

The parking structure features glass and steel

exterior cladding that required tight tolerances

for the steel frame.

companies. The steel erector faced thechallenge of having to perform multipleactivities simultaneously to achieve theaggressive concrete-on-metal deck place-ment schedule.

The use of steel for parking structurescontinues to increase, with long-spansystems, high-performance coatings, re-

duced foundation loads, and aestheticsamong the main considerations for thatchoice. The Legacy Salmon Creek Hos-pital parking structure exemplifies allof these attributes by combining uniqueand pleasing architecture with the latestin steel technology.

James Sarka is a project manager for R.F.Stearns, Inc. Roger O’Hara is Operations

Manager for R.F. Stearns, Inc.

OwnerLegacy Health System, Portland, OR

ArchitectZimmer Gunsul Frasca Partnership,

Portland, OR

Structural EngineerKPFF Consulting Engineers,

Portland, OR

Engineering SoftwareRAM Structural System and ETABS

Structural Steel Contractor/DetailerR.F. Stearns, Inc., Portland, OR,

AISC member

Detailing SoftwareAutoCAD

FabricatorMetals Fabrication Co., Spokane, WA,

AISC member

General ContractorSkanska USA Building, Inc., Portland, OR

SmartBeam® SupplierSMI Steel Products, Hope, AR,

AISC member

14 MODERN STEEL CONSTRUCTION JULY 2005



ON PARKING GARAGESSTRENGTH I was always amazed by the strength

of building materials and how they could resist

stress. That’s one thing that got me interested in

engineering when I was growing up. I was around a

lot of construction with my uncle who would buy

properties for development of residential buildings.

When I wasn’t in school, I was helping him.

PLANNING You always look out for the best

interest of the client. That means not over-building

unnecessary parking spaces. For instance, for a

garage serving an office building, we tabulate peak

occupancy rates through observations and surveys.

Then we compare that to the square footage of the

particular building to come up with the ratio of

spaces per 1,000 square feet of flooring. But for a

hospital, the parking ratio isn’t based on square

footage – it’s based on the number of beds they

have. Although outpatient parking – like an office –

is linked to square footage to determine need.

PROCESS We find that designing a structure is

as enjoyable as seeing the end results. But that

depends on whom you talk to because it’s different

for everyone.

WEATHER A parking structure should not corrode or

crack because both will cause expensive

maintenance problems. Slab cracking is always

an issue of concern. In Colorado, the snow and

road salt tracked into garages by cars can cause

considerable damage to concrete and steel. Water

leaching through cracks in slabs can drip down on

cars parked below. This salt-contaminated water

can damage paint on cars.

DURABILITY Steel frames can be a very competitive

system for parking garages. We just finished a

steel parking structure for employee parking at

the Northern Colorado Medical Center (NCMC).In the past, some owners didn’t want steel because

it was painted with a single-coat system and the

eventual maintenance was not desirable –

repainting would eventually be required. The

advantage for steel now is that members can be

galvanized at the end of the mill run or painted

with a high-performance coating system. For the

NCMC, the members were hot-dipped galvanized

in an 80-foot cauldron. As a result, we were able

to give the owner a steel parking structure that

will effectively resist corrosion with a 125-year

service life.

Hoshi & Don

Hoshi Engineer, P.E., SE, Principal and Regional Chief Structural Engineer

for Walker Parking Consultants’ Engineering Resources Group in Denver. Hoshi

oversees production of structural design, and is responsible for proactive structural

design support, project planning, training of engineers and development of

engineering design aids and standards.

Donald R. Monahan, P.E., Vice President, Walker Parking Consultants in Denver.

With more than 26 years experience and 500+ multi-level parking structures to his

credit, Don has chaired the Parking Consultants Council and currently sits on the

Board of Directors for the National Parking Association.

TIME We went through an exercise to evaluate

various structural system costs for the NCMC

parking structure. The study covered pre-cast

concrete, cast-in-place post-tensioned concrete and

a steel frame with a post-tensioned floor. All were

roughly the same cost, but the steel-framed parking

structure saved two months in construction time –

we went from a 10-month schedule down to eight

months – primarily due to the speed of erection

even through the winter.

COST Using steel shortens construction time,

which reduces overhead expense for the contractor.

At the NCMC, the original scope of work was to

design a 600-car parking structure, but after

project estimates came in under budget, the owner

decided to add another level to gain an additional

120 spaces.

EXPANSION A couple of years before we built the

steel parking structure at the NCMC, Walker

Parking Consultants did a feasibility study to

determine their current and future needs based

on planned growth. The old employee parking

area was on grade and is now the site of the new

medical towers currently under construction.

A parking structure takes advantage of vertical

space and allows for expansion on an already

crowded campus.

CAPACITY The owner received a variance change to

the city ordinance that gave the NCMC site

a setback requirement of 10 feet instead of the

original 25 feet. City ordinances also set a height

limitation of 30 feet. We maximized both limits and

designed a structure that gave them 720 spaces.The relative shallowness of the steel beams allows

us to have an open structure with adequate

headroom.

STEEL The parking structure we built at NCMC is

for the employees. Shifts start and end at different

times throughout the day because hospitals are

24-hour facilities. Security was a major issue to

address. With steel, the columns are smaller in size

than concrete – and less obtrusive. You can see

around the columns and be confident no one is

hiding behind them. The shallow profile of the floor

beams provides more openness, which makes the

space much easier to illuminate – another security

advantage. In this respect, steel provides a user-

friendly design approach for parking structures.

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Structural Steel: The Material of Choice



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