Modern Steel Construction_june14

June 2014

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MoDern steeL ConstruCtion (Volume 54, number 6) issn (print) 0026-8445: issn (online) 1945-0737. Published monthly by the american institute of steel Construction (aisC), one e. Wacker Dr., suite 700, Chicago, iL 60601. subscriptions: Within the u.s.single issues $6.00; 1 year, $44. outside the u.s. (Canada and Mexico)single issues $9.00; 1 year $88. Periodicals postage paid at Chicago, iL and at additional mailing offices. Postmaster: Please send address changes to MoDern steeL ConstruCtion, one east Wacker Dr., suite 700, Chicago, iL 60601.

DISClAIMeR: aisC does not approve, disapprove, or guarantee the validity or accuracy of any data, claim, or opinion appearing under a byline or obtained or quoted from an acknowledged source. opinions are those of the writers and aisC is not responsible for any statement made or opinions expressed in MoDern steeL ConstruCtion. all rights reserved. Materials may not be reproduced without written permission, except for noncommercial educational purposes where fewer than 25 photocopies are being reproduced. the aisC and Modern steel logos are registered trademarks of aisC.

june 2014

On the COveR: the Phyllis j. tilley Memorial Pedestrian bridge, fort Worth, texas, Prize bridge awardspecial Purpose Category, p. 32. (Photo: )

business issues 17 how green Are We?

by john Cross, P.e.The more input we receive from our industry, the more completely we can attempt to answer that question.

23 nSBA 2014 Prize Bridge AwardsThis years Prize Bridge Awards winners range from a reconstructed bridge that had been partially destroyed by a barge to a massive delta frame spanning the Shenandoah River.

50 long life for longfellowby jiM taLbotBuilt to be one of the finest and most beautiful bridges in the country, Bostons Longfellow Bridge gets a modern upgrade while maintaining the character dictated by its original vision.

54 Safety hazard Prevention, By Designby jie ZuoWhen safety is addressed during design, it can become easier to implement during construction.

column

features

departments 6 eDitors note 9 steeL interChanGe 12 steeL QuiZ 59 neW ProDuCts 60 neWs & eVents 66 struCturaLLy sounD

resources

64 MarKetPLaCe 65 eMPLoyMent

in every issue

23

PriZe briDGe aWarD & sustainabiLity CoMMenDationreconstructed Categoryhuey P. lOng BRIDge, neW ORleAnS, lA., p. 30

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6 june 2014

editorial Offices1 e. Wacker Dr., suite 700Chicago, iL 60601312.670.2400 tel

editorial ContactseDitor & PubLisherscott L. [email protected]

senior eDitorGeoff [email protected]

assistant eDitortasha [email protected]

DireCtor of PubLishinGareti [email protected]

GraPhiC DesiGnerKristin [email protected]

AISC OfficersChairjeffrey e. Dave, P.e.

ViCe Chairjames G. thompson

seCretary & GeneraL CounseLDavid b. ratterman

PresiDentroger e. ferch, P.e.

ViCe PresiDent anD Chief struCturaL enGineerCharles j. Carter, s.e., P.e., Ph.D.

ViCe PresiDentjacques Cattan

ViCe PresiDentjohn P. Cross, P.e.

ViCe PresiDentscott L. Melnick

Advertising Contactaccount ManagerLouis Gurthet231.228.2274 tel231.228.7759 [email protected]

for advertising information, contact Louis Gurthet or visit www.modernsteel.com

Address Changes and Subscription Concerns312.670.5444 tel312.893.2253 [email protected]

Reprintsbetsy Whitethe reprint outsource, [email protected]

editors note

SCOtt MelnICkeDitor

DuRIng My quARteR-CentuRy At AISC, ive had a wonderful time meeting and hearing stories from some of the most significant people in the structural steel industry. from Duane Miller to egor Popov to jon Magnusson, ive been lucky to share a moment or two of their time.

But other than my knowing them, can you guess what else they have in common?

Theyre all winners of AISC Lifetime Achievement Awards. During the past 15 years, AISC has presented 68 Lifetime Awards, 70 Special Achievement Awards, seven Robert P. Stupp Awards for Leadership Excellence, five J. Lloyd Kimbrough Awards and six Geerhard Haaijer Awards for Excel-lence in Education.

Ive had the privilege of being the only per-son to have sat in on every meeting of the vari-ous awards committees that nominated these 156 peopleand Ive been able to suggest those whom I believe have made a significant contri-bution to AISC and the structural steel industry.

But if you had the opportunity to give an award, who would you nominate? Who de-serves an AISC Lifetime Achievement Award? These awards honor living individuals who have made a difference in AISCs and the structural steel industrys success. They pro-vide special recognition to individuals who have given outstanding service over a sus-tained period of years.

The individual should have: made a positive impact on advancing the

use of structural steel many years of sustained service to AISC

(such as involvement on AISC Commit-tees and Task Groups as well as successful completion of AISC special assignments)

earned recognition from other industry groups

the respect of their professional peers been generally acknowledged as having

reached the pinnacle of their profession demonstrated, over an extended period

of time, innovation and originality in design, construction or academic con-cepts in structural steel design

What about a Special Achievement Award? These awards provide special recognition to individuals who have demonstrated notable singular or multiple achievements in struc-tural steel design, construction, research or education. They honor living individuals who have made a positive and substantial impact on the structural steel design and construc-tion industry. Here are the criteria:

The award is presented for achievement on projects or research that showed in-novation and originality and helped to ad-vance the use of structural steel. The event for which the individual is honored should have made a positive and substantial im-pact on the structural steel industry.

The event for which the individual is honored should be recognized by the individuals peers as to the impact of the achievement.

Individuals are eligible to receive more than one Special Achievement Award if future activities warrant additional awards.

AISC also is accepting nominations for the Stupp, Haaijer and Kimbrough Awards. These awards are only presented occasionally, and only to those who stand head-and-shoulders above their peers.

If you have potential nominees for any of these awards, Id love to hear them! Visit: www.surveymonkey.com/s/aiscaward and fill out the brief form. And to learn more about these awards and view a list of previous winners, visit www.aisc.org/awards.

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Modern Steel ConstruCtion 9

Drift limitsFor a single-story steel moment frame building with CMU non-load-bearing walls, what requirements control the analysis requirements and allowable lateral displace-ment of the frame?

The intent of the AISC 360 Specification (a free download from www.aisc.org/2010spec) is to provide requirements related to the design and detailing of steel systems for the forces resulting from an analysis. It is not intended to dictate the analysis procedure itself. Analysis requirements are typically addressed in the building code, such as IBC, or in ASCE 7 in the absence of an applicable building code.

That said, there are a couple objectives to be considered in establishing analysis and lateral displacement criteria. First, there is structural stability, and this is addressed to some degree in the building codes as follows:

Basic requirements in ASCE 7-10, Section 1.3 Stability coefficient requirements in ASCE 7-10, Section

12.8.7 Seismic drift limits as defined in ASCE 7-10, Section

12.12Structural steel-related stability requirements are given in

Chapter C of AISC 360-10, and some of the related methods and provisions are covered in Appendices 7 and 8.

There also are serviceability criteria. These are not addressed prescriptively in the codes and should be evaluated on a project-specific basis, taking into consideration the end users needs and expectations, the architectural finishes (exterior and interior) and the detailing of how those finishes will attach to the structure and/or accommodate structure movements. ASCE 7-10 Appendix C addresses serviceability requirements, but in very general terms.

In my practice, I often refer to the 1993 AISC Engineering Journal article Serviceability Limit States Under Wind Load, written by Larry Griffis. In this article, he discusses drift limits in depth and provides some guidelines for establishing limits based on different material finishes. Additionally, there is AISC Design Guide No. 3 Serviceability Design Considerations for Steel Buildings, 2nd Edition. These resources are available for free download by AISC members at www.aisc.org/epubs.

Susan Burmeister, P.E.

grouting of Base PlatesWhen should the base plates be grouted for a multistory structure?

AISC Design Guide 10 (a free download at www.aisc.org/dg) provides the following guidance on this subject: Until the column bases are grouted, the weight of the framework and any loads upon it must be borne by the anchor rods and leveling nuts or shims. These elements have a finite strength. The timing of grouting of bases

must be coordinated between the erector and the general contractor.

It also states: Leveling nuts bear the weight of the frame until grouting of the bases. Because the anchor rod, nut and washers have a finite design strength, grouting must be completed before this design strength would be exceeded by the accumulated weight of the frame. For example, the design strength of the leveling nuts may limit the height of frame to the first tier of framing prior to grouting. Also, it is likely that the column bases would have to be grouted prior to placing concrete on metal floor deck. Properly installed shim stacks can support significant vertical load. There are two types of shims: those placed on (washer) or around (horseshoe) the anchor rods. Shims placed on or around the anchor rods will have a lesser tendency to become dislodged. Independent shims must have a reasonable aspect ratio to prevent instability of the stack. In some instances shim stacks are tack welded to maintain the integrity of the stacks. When shim stacks are used, care must be taken to ensure that the stacks cannot topple, shift or become dislodged until grouting. Shims are sometimes supplemented with wedges along the base plate edges to provide additional support of the base plate.

AISC Design Guide 1 also provides some guidance. Section 2.9.1 states: When designing anchor rods using setting nuts and washers, it is important to remember these rods are also loaded in compression and their strength should be checked for push out at the bottom of the footing. It is recommended that use of the setting nut and washer method be limited to columns that are relatively lightly loaded during erection.

Section 2.9.3 states: Column erection on steel shim stacks is a traditional method for setting base plate elevations that has the advantage that all compression is transferred from the base plate to the foundation without involving anchor rods. Steel shim packs approximately 4 in. wide are set at the four edges of the base plate. The areas of the shim stacks are typically large enough to carry substantial dead load prior to grouting of the base plate.

Carlo Lini, P.E.

PJP groove Welds in CompressionAISC Specification Table J2.5 provides three conditions related to partial-joint-penetration groove welds subjected to compression:

1) Column-to-base plate and column splices designed per Section J1.4(1)

2) Connections of members designed to bear other than columns as described in Section J1.4(2)

3) Connections not finished-to-bearFor case 2, the nominal strength of the weld is 0.6 FEXX. For case 3, the nominal strength is 0.9 FEXX. Why is the weld assumed to have less strength when the members are finished-to-bear than when the members are not finished-to-bear?

steel interchange

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monthly Steel Interchange column is for you! Send your questions or comments to [email protected].

10 june 2014

The Commentary to the AISC Specification provides the following information related to the first two cases:

Column splices have historically been connected with relatively small PJP groove welds... Section M4.4 recognizes that, in the as-fitted product, the contact may not be consistent across the joint and therefore provides rules assuring some contact that limits the potential deformation of weld metal and the material surrounding it. These welds are intended to hold the columns in place, not to transfer the compressive loads. Additionally, the effects of very small deformation in column splices are accommodated by normal construction practices Therefore the compressive stress in the weld metal does not need to be considered as the weld metal will deform and subsequently stop when the columns bear. Other PJP groove welded joints connect members that may be subject to unanticipated loads and may fit with a gap. Where these connections are finished to bear, fit-up may not be as good as that specified in Section M4.4, but some bearing is anticipated and the weld is designed to resist loads defined in Section J1.4(2) using the factors, strengths and effective areas in Table J2.5.

Essentially what the Commentary is saying is that with a column, we expect pretty good (but not perfect) bearing. With members other than columns we expect pretty good (but maybe less perfect) bearing. We have a lot of certainty relative to what a column is, what its connection will look like and how it will behave. We have less certainty relative to what a member other than a column is, what its connection will look like and how it will behave, but we still design the weld for little load based on the fact that the members bear, so we knock down the strength of the weld to account for the uncertainty.

Now that weve compared Cases 1 and 2, lets compare Cases 2 and 3. For Case 2, we already discussed that we use 0.6 because we ask little of the weld in terms of the design load, but we have a good bit of uncertainty. For the members not designed to bear, we ask a lot of the weld, but we feel we have little in the way of uncertainty. For instance, for tension on a PJP groove weld, where we also apply the 0.6 factor, the Commentary states:

The factor 0.6 on FEXX for the tensile strength of PJP groove welds is an arbitrary reduction that has been used since the early 1960s to compensate for the notch effect of the unfused area of the joint, uncertain quality in the root of the weld due to the inability to perform nondestructive evaluation and the lack of a specific notch-toughness requirement for filler metal. It does not imply that the tensile failure mode is by shear stress on the effective throat, as in fillet welds.

For PJP groove welds in compression, were not really concerned with any of these factors, which explains why we permit a higher nominal stress for Case 3.

Larry S. Muir, P.E.

Stiffened Plates in flexureWhat section(s) in the AISC Specification can be used to determine effective width of stiffened plates used in built-up sections subjected to flexure?

Because the AISC Specification is written with buildings and other structures similar to buildings in mind, there are no provisions for the effective width of plate in stiffened plate structures. The effective width used in design varies, depending on the type of structure you are designing (bin, stack, tank, ship, etc.). For general flat plate structures, API Bulletin 2V, Design of Flat Plate Structures, published by the American Petroleum Institute, can be used to determine the effective width.

A few of other sources may also be helpful: Page 6.6-7 of Design of Welded Structures by Blodgett

uses an effective width of 12t on each side of the stiffener, where t is the plate thickness. This is similar to the value in Section J10.8 of the 2010 AISC Specification (a free download available from www.aisc.org/2010spec), which allows an effective width of web to be used in the design of stiffened beam and plate girder webs.

Tables B4.1a and B4.1b of the AISC Specification can be used to determine the maximum effective width of compression elements.

The steel stack code, ASME STS-1, allows an effective width of only 8t on each side of the stiffener.

Bo Dowswell, P.E., Ph.D.

steel interchange

Larry Muir is director of technical assistance and Carlo Lini is staff engineertechnical assistance at aisC. susan burmeister and bo Dowswell are consultants to aisC.

steel interchange is a forum to exchange useful and practical professional ideas and information on all phases of steel building and bridge construction. opinions and suggestions are welcome on any subject covered in this magazine.

the opinions expressed in steel interchange do not necessarily represent an official position of the american institute of steel Construction and have not been reviewed. it is recognized that the design of structures is within the scope and expertise of a competent licensed structural engineer, architect or other licensed professional for the application of principles to a particular structure.

if you have a question or problem that your fellow readers might help you solve, please forward it to us. at the same time, feel free to respond to any of the questions that you have read here. Contact steel interchange via aisCs steel solutions Center:

1 e Wacker Dr., ste. 700, Chicago, iL 60601tel: 866.ASK.AISC fax: [email protected]

the complete collection of steel interchange questions and answers is available online. find questions and answers related to just about any topic by using our full-text search capability. Visit steel interchange online at www.modernsteel.com.

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12 june 2014

1 for the following questions, assume that the inflection point is at the midpoint of each story and that the story heights are equal to 12 ft. also assume that the beam axial load is transferred through the beam flange only and that the effect of panel-zone deformation on frame stability is not considered in the analysis.

use the loads shown in figure 1 for asD for design, or 1.5 times the loads shown for LrfD.a) What is the story shear, Vc? b) how does the axial load affect

the web panel zone shear check?

c) What is the required web panel zone shear strength, Vp?

2 Determine the maximum panel zone shear, Vp, for the interior column shown in figure 2. assume an inflection point at mid height of each story, and that the W2150 is CjP groove welded to the W14 column flange. use the following moments for asD, or 1.5 times these moments for LrfD. Dead load moment from each

beam, MDL= 30.0 kip-ft Live load moment from each

beam, MLL= 37.5 kip-ft

Moment due to wind load, MW-1 = MW-2 = 40.0 kip-ft

3 if you are checking panel zone shear for an oMf, iMf or sMf connection, can equations j10-11 and j10-12 in the 2010 aisC Specification be used?

4 size the doubler plate thickness required along with the required weld sizes for Weld a and Weld b shown in figure 3. the required shear strength of the doubler plate, VDP, is equal to 30 kips for asD and 45 kips for LrfD. use astM a36 plate material.

5 Which is most economical?a) adding a column web doublerb) adding a full depth stiffenerc) upsizing a column to avoid the

use of a stiffener and/or doublerd) adding a partial stiffener

The answers to this months Steel Quiz can be found in AISC Design Guide 13 Wide-Flange Column Stiffening at Moment Connections as well as on the AISC and Modern Steel Construction websites (www.aisc.org and www.modernsteel.com). steel quiz

turn to PaGe 14 for ansWers

16

Weld a

Weld b

W1443

Doubler Plate ns only

W14

43 MW-2

MW-1W2150W2150

30-030-0

12-0

14

-0

Calculate maximum panel zone shear.

160k

W1443W1640

20k

100 k-ft

fig. 1

fig. 2

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14 june 2014

ansWerssteel quiz1 a) the story shear, Vc, is determined by dividing the

sum of the moments transferred to the column by the distance between the inflection points, h. the total moment transferred to the column is equal to 100 ft-k and the distance between the panel points is equal to 12 ft. therefore, Vc = 100 kip-ft/12 ft = 8.33 kips for asD; 12.5 kips for LrfD by similar process (see figure 4, below).

b) the axial load transferred to the column does not affect the shear in the panel zone, just the shear in the column below the panel zone. note that section j10.6 states, this section applies to double-concentrated forces applied to one or both flanges of a member at the same location. Double-concentrated force is defined in the aisC Specification as two equal and opposite forces applied normal to the same flange, forming a couple.

c) the required web panel zone shear strength, Vp, is equal to the beam flange force due to the moment (the axial force is ignored in this calculation), minus the story shear (see figure 4). the flange force, Pf, is equal to the moment divided by the moment arm, which is equal to the depth of the beam minus the thickness of the beam flange. for asD, Pf = 100 kip-ft 12 in./ft/(16 in. 0.505 in.) = 77.4 kips, and Vp = 77.4 kips 8.33 kips = 69.1 kips. for LrfD, by similar process, Pf = 116 kips and Vp = 104 kips.

2 for the asD solution, the required shear strength for the panel zone is 33.0 kips. the moment due to dead load is equal and opposite on both sides of the column and cancels out. to maximize the panel zone shear, live load is considered on one side only, and the controlling load combination is 0.75L + 0.75(0.6W). the sum of the moments at this location is equal to 0.75MLL + 0.750.6 (MW-1+MW-2) = 0.75 37.5 kip-ft + 0.75 0.6 (40.0 kip-ft + 40.0 kip-ft) = 64.1 kip-ft. the distance between the inflection points is equal to (12 ft/2)+(14 ft/2) = 13 ft.

the story shear is Vc = 64.1 kip-ft/13 ft = 4.93 kips. the required strength for the web panel zone shear is equal to the total flange force (sum of moments divided by the moment arm) minus the story shear. this equals Vp = [64.1 kip-ft 12 in./ft/(20.8 in. 0.535 in.)] 4.93 kips = 33.0 kips. for LrfD, the corresponding answer by similar process is 49.5 kips.

3 yes. Commentary section e1.6b in the aisC Seismic Provisions states: the required shear strength of the panel zone may be computed from the basic code prescribed loads, with the available shear strength computed using equations j10-11 and j10-12 of the Specification. this may result in a design where initial yielding of the frame occurs in the panel zones. this is acceptable behavior due to the high ductility exhibited by panel zones.

4 for LrfD, the required web doubler plate thickness is equal to tDP =VDP/(0.6Fydcol)=45kips/(0.9 0.6 36 ksi 13.7 in.) =0.168 in. the asD solution results in the same thickness by similar calculation. use a -in. plate.

for Welds a the flange force is delivered directly to the doubler, and these can be minimum-size fillet welds. for Welds b, the shear load that is transferred is equal to 45 kips 16 in./(13.7 in. (2 0.53 in.)) = 57.0 kips. the weld length is equal to 16 in. therefore the required fillet weld leg size = 57.0 kips / 1.392 kips/in./sixteenth 16 in. = 2.6 sixteenths. the asD solution results in the same requirement by similar calculation.

Can we use a 3/16-in. fillet weld? Probably not, because a fillet weld detail must account for the plate bevel and its effect on the doubler capacity; the bevel changes the effective throat in most cases (this is illustrated in aisC Design Guide 13). this can be accounted for by making the plate thicker or the fillet weld larger or both. Depending on the preference of the fabricator, it may be more economical to prepare the doubler plate and use a groove weld. refer to figure 4-13 in aisC Design Guide 13 for more information.

5 c) almost always. When it comes to designing column doublers and/or column stiffeners, it is nearly always more economical to size a column to avoid adding these types of reinforcement because shop labor is far more expensive than material cost. sometimes, stiffening cant be avoidedbut when it can it should be.

fig. 4

inflection point assumed at h/2

Vc = Mbeam/h = 100 k-ft /12 ft = 8.3k

Check web panel zone shear for shear at panel zone, Vp

Vp

Vc

Vc

h =

12

ft

Vc

dbeam tflg

Pf

Pf

Where:Pf = Mbeam/(dbeam tflg)Pf = 100 k-ft /(16-0.505) = 77.4 k

a) force Distribution b) shear Diagram

anyone is welcome to submit questions and answers for steel Quiz. if you are interested in submitting one question or an entire quiz, contact aisCs steel solutions Center at 866.asK.aisC or at [email protected].

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Modern Steel ConstruCtion 17

I hAve Often Been ACCuSeD of bleeding green because of my fanatical loyalty to the Green Bay Packers. But how green am I, really?

It is one thing to say that I am green but quite another to prove it. My proof comes in a variety of ways: season tick-ets at Lambeau Field; stock in the Packers; jerseys from Favre, Rodgers, Cobb, Driver, Bulaga and Gado; a spotlighted 5-ft-tall combination green G and Lombardi Trophy in my front yard, XLVPACK license plates, myriad other Packer memo-rabilia and most importantly the Packer flag that flew in front of the office of Illinois Governor Pat Quinn to pay off a bet with Wisconsin Governor Scott Walker after the Packers beat the Bears in the 2010 NFC Championship game (yes, that was mine). When it comes to being a Packers fan, I can objectively demonstrate how green I am.

Fabricated structural steel is touted as a green construction material. But how green are we?

Just as I can demonstrate my Packer greenness in a variety of ways, we can also demonstrate the greenness of fabricated structural steel. Steel is the most recycled material in the world and structural steel has one of the highest percentages of recy-cled content of any steel product, often approaching 100%. At the same time it is currently estimated that 98% of all structural steel at the end-of-life is recycled back into new steel products. From an emissions perspective we know that since 1990, energy intensity, per ton, from steel production has been reduced by 28% and carbon emissions have declined by 35%. Studies have been performed that demonstrate that the embodied environ-mental impacts of steel-framed buildings are equal to or less than buildings constructed in concrete or wood. We can objec-tively demonstrate how green we are.

everyones greenBut just as nearly every Packers fan can claim to be green in

some way, so can nearly every construction material. Structural steel is recycled, concrete is regional and wood is bio-based. These competing claims have created confusion in the market-place as well as a knee-jerk reaction on the part of members of the green construction community against what they have wrongly labeled as single-attribute materials. The problem isnt single-attribute materials, but rather single-attribute eval-uation methodologies. To overcome this concern, the major sustainability codes, standards and rating systems have placed a higher degree of emphasis on encouraging transparency in the reporting of environmental impacts associated with the pro-duction of all construction materials.

LEED V4, which entered the marketplace last November, provides credit to projects that use at least 20 products that have published environmental product declarations (EPDs). The ASHRAE 189.1 committee is in the process of amending that standard (Standard for the Design of High-Performance, Green Buildings) to include the provision of 10 EPDs as a compliance path for material selection. And a variety of proposals are working their way through the International Green Construction Code process to require the provision of EPDs.

Simply put, structural steel fabricators will soon be asked by general contractors (who in turn would have been asked for these by architects, engineers or project owners) to supply EPDs on projects following LEED, ASHRAE or IgCC guide-lines and requirements.

At the same time, there is an increasing emphasis on the performance of life-cycle assessments (LCAs) comparing the environmental impacts of products, assemblies or whole build-ings as a means of lessening the overall impact of building con-struction and operation on the environment.

The difference between an EPD and an LCA is that the EPD is a summary statement of the LCA, listing only five or six impact categoriessuch as global warming potential, ozone depletion, acidification, eutrophication and primary energy consumptionwhile the LCA will go into much greater detail on individual processes and impacts associated with those processes.

The data required to either construct an EPD or to conduct an LCA originates in a life-cycle inventory (LCI) of the processes and material required to produce a product. In the case of fab-ricated structural steel this means collecting data from mills that produce hot-rolled sections, plate or coil regarding their inputs

hOW gReen ARe We?by john Cross, P.e., LeeD aP

business issuesThe more input we receive from our industry, the more completely we can attempt

to answer that question.

John Cross ([email protected]) is an aisC vice president.

18 june 2014

of raw materials and energy and their outputs of steel, byproducts and emissions. In the case of hollow structural sections (HSS) the inputs and outputs of the secondary process of creating HSS from coil are added to the LCI information for coil production itself.

key ComponentBut the process does not end there. The product delivered to

the job site is not a hot-rolled section, steel plate or HSS. The delivered product is a fabricated hot-rolled section, a fabricated steel plate or a fabricated HSS. This means that inputs and out-puts associated with the fabrication process must also be included.

AISC is currently working with an outside consultant and the three AISC member hot-rolled structural mills to develop indus-try average LCI data for use in producing an LCA for hot-rolled structural steel. We are also discussing the development of similar data for HSS with the three AISC member HSS producers and the Steel Tube Institute. Plate data will be available through AISI.

Again, these are not the products that are delivered to the job site. What is delivered to the job site is fabricated product, so the EPD will need to be for fabricated structural steel. This means that as an industry we must collect the data necessary to develop industry average fabrication impacts. This was done internally by AISC a few years ago in the form of a brief survey

of our fabricator members, but now must be redone in a more rigorous manner using an outside consultant so the EPDs that are produced can be certified by a third party.

A Clearer PictureIf you are a fabricator member of AISC, later this summer

you will be receiving a questionnaire that will include questions regarding your 2013 production tonnage, material purchases, waste, electricity consumption, water consumption and data on a variety of other consumables. In addition, you will be asked to identify your firm and the location of your shop by zip code in order that the consultant can determine the electric power grid mix (renewable, coal, natural gas, nuclear) in your area. Only the consultant will see your individual shop responses, with all data being reported to AISC as anonymous averages. A list of partici-pating firms will be posted on the AISC website.

Im sure you are already asking yourself, Is this really neces-sary? Thats a perfectly valid question.

For all the hype we hear about green buildings, adoption of green codes and standards has been much slower than anticipated. LEED V4 is a quantum leap in complexity beyond LEED 2009 (see Up To Speed on LEED, 02/2014) and green construction practices have not lived up to their economic

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fabrication environmental impacts by source (from the 2010 aisC member fabricator survey). note the dominance of electricity consumption.

promisesi.e., additional construction costs have not been jus-tified by operational savings. This may mean that fewer projects will pursue LEED certification or be required to comply with the requirements of the green codes and standards. I doubt you will be asked to provide an EPD for fabricated structural steel on the majority of your projects over the next three to four years. But you will be asked for this information on some of your projects, and architects and engineers will be making deci-sions relating to the framing systems for projects based on the LCA data available for comparative construction materials.

the More the MerrierSo now you are probably saying to yourself, If this is indus-

try average data, Ill let everyone else submit their data and just provide the industry average EPD when asked. Well, that doesnt quite work for two reasons.

First, LEED contains some qualifying language of the EPD that says it can only be used by firms in which the manufac-turer is explicitly recognized as a participant by the program operator. While the interpretation of what this means is under discussion within USGBC, it is clear that if you want to make sure you can use the industry average EPD to meet the require-ments of your project you will at a minimum need to be an AISC member and have participated by submitting your shops data. (Note: This also means that the industry average EPD data will only apply to mill material supplied from producers that participated in the collection of mill data.)

Second, if everyone took that attitude, we wouldnt be able to develop an industry average!

On top of that, it is also possible that you may want to develop an EPD that is specific to your shop. A company-specific EPD receives more credit under LEED V4 than an industry average EPD and could be used to demonstrate that

the environmental performance of your company exceeds the industry average. That is the theory being promoted by the green community as a motivation for improving overall envi-ronmental performance. However, it is questionable whether company-specific EPDs have any realistic meaning in the structural steel industry.

The environmental impacts of the fabricating process vary greatly by the requirements of each specific project, and the mix of projects being fabricated in a shop will vary year to year. Some will be high-tonnage, low-shop-hour projects while oth-ers may require significantly more shop activity on a per-ton basis. For that reason, EPDs on a per-shop basis will not be an accurate estimate of actual environmental impacts for a given project or shop and are therefore not a valid basis for compari-son of a specific firm with the industry average.

If you are following all of this, you may have just had a light bulb go on and realized that even the industry aver-age EPD or LCA for fabricated structural steel doesnt really capture what the actual environmental impacts will be for a specific project. You are absolutely correct! They are only an average of the average shops average project. The cur-rent process does not allow for any adjustment of the EPD or LCA based on the level of complexity of a given project, thus making it our goal to include language in the EPD that highlights this concern.

Bottom line: There will be an industry average EPD and LCA for fabricated structural steel (hot-rolled, HSS and plate). At a minimum, the EPDs will be available to AISC members that participate in the shop data collection effort to meet the documentation requirements of green rating systems, codes and standards (keep an eye out for the survey later this sum-mer). From there, we will be able to objectively demonstrate how green fabricated structural steel is.

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Global Warming Potential [kg Co2-equiv.]

eutrophication Potential [kg n-equiv.]

acidification Potential [mol h+ equiv.]

smog Potential [kg nox-equiv.]

total Primary energy Demand [Mj]

non-renewable Primary energy Demand [Mj]

0 10 20 30 40 50 60 70 80 90 100 %

acetylene truck, Diesel toluene

argon truck, Gasoline Waste to Landfill

Carbon Dioxide electricity Water

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oxygen natural Gas

Propene Propene thermal

environmental impacts from average steel fabrication

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Modern STEEL CONSTRUCTION 23

FiFTEEn bridgES havE EarnEd national recognition in the 2014 Prize Bridge Awards Competition. Conducted by the National Steel Bridge Alliance (NSBA), the program honors outstanding and innovative steel bridges constructed in the U.S.

The awards are presented in several categories: major span, long span, medium span, short span, movable span, reconstructed, special purpose, accelerated bridge construction and sustainability. This years winners range from a reconstructed bridge that had been partially destroyed by a barge to a massive delta frame spanning the Shenandoah River.

Winning bridge projects were selected based on innovation, aesthetics and design and engineering solutions, by a jury of five bridge professionals: Benjamin Beerman, Senior Structural Engineer,

Federal Highway Administration/Resource Center, Atlanta

Thomas R. Cooper, P.E., P.Eng., Lead Structural Engineer, Parsons Brinckeroff, Denver

Robert Healy, Director of Structures, RK&K, Baltimore

Thomas P. Macioce, P.E., Division Chief of the Bridge Design and Technology Division, Pennsylvania Department of Transportation, Harrisburg, Pa.

Bert Parker, Senior Vice President/Chief Administrative Officer, Garver, Little Rock, Ark.

This years competition attracted more than 30 entries and included a variety of bridge structure types and construction methods. All structures were required to have opened to traffic between May 1, 2011 and September 30, 2013.

The competition originated in 1928, with the Sixth Street Bridge in Pittsburgh taking first place, and over the years more than 300 bridges have won in a variety of categories. Between 1928 and 1977, the Prize Bridge Competition was held annually, and since then has been held every other year, with the winners being announced at NSBAs World Steel Bridge Symposium.

NSBA2014 Prize Bridge

AWARDS2014 PrizE bridgE award winnErSPrize bridge award winners Major Span: Shenandoah River Bridge Delta Frame,

Jefferson County, W.Va. Medium Span: Dixie Highway Flyover, Boca Raton

and Deerfield Beach, Fla. Moveable Span: Willis Avenue Bridge, New York Reconstructed: Huey P. Long Bridge, New Orleans Special Purpose: Phyllis J. Tilley Memorial Pedestrian

Bridge, Fort Worth, Texas

Merit award winners Major Span: Sakonnet River Bridge, Tiverton and

Portsmouth, R.I. Long Span: Iowa Falls Bridge, Iowa Falls, Iowa Medium Span: North Halsted Street Tied Arch

Bridge, Chicago Medium Span: Ramp TE over I-95, New York Short Span: River Road Over Ironstone Brook,

Uxbridge, Mass. Short Span: Dodge Creek Bridge, Elkton-Sutherlin

Highway (OR138), Ore. Reconstructed: Eggners Ferry Bridge Emergency

Replacement, Trigg and Marshall Counties, Ky. Special Purpose: Christina and John Markey

Memorial Pedestrian Bridge, Revere, Mass.

accelerated bridge Construction Commendations Willis Avenue Bridge, New York River Road Over Ironstone Brook, Uxbridge, Mass. 130th Street and Torrence Avenue Railroad Truss

Bridge, Chicago Eggners Ferry Bridge Emergency Replacement, Trigg

and Marshall Counties, Ky.

Sustainability Commendations Dodge Creek Bridge, Elkton-Sutherlin Highway

(OR138), Ore. Huey P. Long Bridge, New Orleans Keene Road Bridge, Richland, Wash.

24 JUNE 2014

The opening verse to John Denvers Take Me Home, Country Roads hints at the natural beauty of the Shenandoah River Valley in West Virginias eastern panhandle.

To accommodate increasing travel demands to the area, which is about an hour from Washington, D.C., the West Virginia Division of Highways initiated a project to improve West Virginia High-way 9, including a new bridge across the Shenandoah River. HDR developed a delta frame design that delivered signifi -cant savings compared to proposals for more traditional designs. The resulting signature shape of the Shenandoah River Bridge is as pleasing to the bottom line as it is to the eye.

The triangular shape of the delta frame, one of the most basic structural forms, yields a sense of stability and strength, of simplicity and functionality. The earth-tone reddish-brown color of the weathering steel blends with the nat-ural colors of the valley and is bounded and complemented by the natural con-crete color of the deck and barriers, as well as the piers and abutments.

HDR and Trumbull performed prelimi-nary design on both concrete and steel options, but the anticipated construction

PRIZE BRIDGE AWARD Major Span CategoryShEnandOah rivEr bridgE dELTa FraME, JEFFErSOn COunTY, w.va.

Something rarely seen, hopefully leading to a resurgence

of this structure type. Benjamin Beerman


costs for concrete were much greater than for steel. There was enough of a dif-ference that it became obvious that steel would be more economical, so the pre-liminary design of the concrete alterna-tive was set aside.

The Shenandoah River Bridge would be one of the longest delta frames ever constructed, with 300-ft spans between legs and 600 ft between main piers. Al-though the bridge type is no longer com-mon, its ability to support long spans at a signifi cant height with few piers made it an ideal fi t for traversing the Shenandoah.

The unique shape of the new delta-frame Shenandoah River Bridge strikes a pose worthy of its picturesque West Vir-ginia surroundings, and delivered signifi -cant savings compared to proposals for more traditional designs. Trumbulls bid of $40 million for the bridge meant that the West Virginia Division of Highways would save $8 million, thanks to this cre-ative design solution; the next lowest bid came in at $48 million.

The new bridge is a much easier structure type to inspect and maintain than some of the other viable bridge types (including the originally proposed truss), especially since it was constructed of uncoated weathering steel. This mate-rial eliminates the need for costly future painting, which also could have had a negative impact on the environment. As part of the design, a future-staged re-decking scheme was presented in the plans and analyzed to ensure its viabil-ity. A potential future deck replacement would not force a temporary closure of the bridge, which would have a negative impact on the public.

You can read more about this project in Decision: Delta (12/2013).

OwnerWest Virginia Department of

Transportation, Division of Highways, Charleston, W.Va.

EngineerHDR Engineering, Inc., Weirton, W.Va.

general ContractorTrumbull Corporation, Pittsburgh

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26 JUNE 2014

The Dixie Highway is done doubling up. The last remain-ing two-lane stretch, in northern Broward and Palm Beach Counties (Fla.), has been expanded to four lanes in the form of a fl yover that crosses the Florida East Coast (FEC) Rail-road, several local streets and the Hillsboro Canal, a waterway that separates the cities of Boca Raton and Deerfi eld Beach.

Two separate structures were constructed using a total of 3,250 tons of structural steel. The main bridge is a 1,390-ft, eight-span, S-curved, steel box girder bridge with a super-ele-vation transition. The steel tubs are 6 ft and 7 ft deep for ease of maintenance and sit 16 ft to 30 ft above grade. The sec-ond bridge is a single-span, 218-ft single steel box pedestrian bridge connecting Pioneer Park in Deerfi eld Beach to Boca Raton over the canal.

Design challenges included integral pier cap girders at each column and the large number of vertical and horizontal clear-ances and transitions between the main bridge and ramps. Waterway width was also a challenge; while Hillsboro Canal is technically a navigable waterway, it is not wide enough to accommodate construction barges. The long box tub girder

spans were lifted into place by two 250-ton crawler cranes working in tandem. It was the fi rst time a 192.5-ton steel cap, the single largest component, was ever lifted over and perma-nently set above the FEC Railroad, which continued to operate freight trains through the construction site every half-hour on weekdays. As construction activities needed to be coordinated with the railroads train schedule, most heavy lifts took place on weekends and overnight hours.

With only seven months allotted for design and release to construction, the fast-track design-build project fi nished 95 days ahead of schedule and $7.5 million under budget. The bridge offi cially opened in July 2012 and was funded through a $40 million American Recovery and Reinvestment Act grant. The completed project, including associated roadway, drain-age, signalization and drainage improvements, eliminates an existing at-grade crossing of the FEC Railroad, reduces travel times for local businesses and residents and provides a more effi cient hurricane evacuation route for the area. Now, all mo-torists, pedestrians, and bicyclists can travel safely and effi -ciently between Boca Raton and Deerfi eld Beach.

PRIZE BRIDGE AWARDMedium Span CategorydixiE highwaY FLYOvEr, bOCa raTOn and dEErFiELd bEaCh, FLa.

Painted steel box girders provided a clean and effi cient solution to a curved alignment traversing the street-level

intersections below. Tom Cooper


OwnerFlorida Department of Transportation, District Four, Fort

Lauderdale, Fla.

EngineerKimley-Horn and Associates, Inc, West Palm Beach, Fla.

general ContractorCone & Graham, Inc., West Palm Beach, Fla.

Steel TeamFabricatorTampa Steel Erecting Company, Tampa, Fla. (AISC Member/NSBA Member/AISC Certified Fabricator)

ErectorV&M Erectors, Inc., Pembroke Pines, Fla. (AISC Member/AISC Certified Erector)

detailerTensor Engineering, Indian Harbour Beach, Fla. (AISC Member/NSBA Member)

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28 JUNE 2014

The Willis Avenue Bridge brings boroughs together. The bridge is integral to connecting Manhattan and the Bronx, carrying roughly 72,000 vehicles per day via four lanes of traffic across the Harlem River. It also provides an important pedestrian and bicycle corridorand is on the route of the New York City Marathon.

The 25-ft vertical clearance of the 350-ft-long swing span

portion allows most vessels in the river to pass below, but the span swings open periodically to permit the passage of tall vessels. Although the swing span is the centerpiece of this bridge, this is just a short segment of the three-quarter-mile-long structure. Elevated ramp connections are provided from First Avenue at E. 125th Street and from the Northbound FDR Drive in Manhattan to Willis Avenue and to Bruckner Boulevard in the Bronx.

PRIZE BRIDGE AWARDMovable Span ACCELERATED BRIDGE CONSTRUCTION COMMENDATIONMovable Span CategorywiLLiS avEnuE bridgE, nEw YOrk

A highly dramatic and incredibly complex example of the fl oat in method of accelerated bridge replacement.

Bert Parker


Due to structural deterioration and alignment issues, the bridge needed to be replaced. The new swing span is a steel through truss and the approach spans include trapezoidal box girders and straight and curved plate girders as well as transverse box girders straddling Harlem River Drive and the at-grade section of Willis Avenue below the bridge. A total of roughly 8,000 tons of structural steel were incorporated in the final project. A separate curved girder ramp, designed by a consultant for New York State DOT, provides a direct connection to the Major Deegan Expressway.

The 2,500-ton swing span portion was preassembled and floated into position on-site. This highly publicized operation included the spectacle of the bridge floating down the Hudson River roughly 160 miles from the assembly site near Albany, including a tour around the tip of Manhattan and below the citys East River bridges. Floating the swing span in allowed simplified erection on land and rapid site installation, minimizing impacts on navigation and vehicular traffic.

A 9-ft-diameter spherical roller thrust bearing supports the entire swing span while minimizing friction during span operation and providing needed seismic restraint. This is the largest application of this type in the world for a spherical roller thrust bearing. Swing span machinery, electrical and maintenance areas were integrated with floor system framing below deck level to simplify future maintenance access and integrate the mechanical and structural components in a way that provided direct load paths from the balance wheels and center wedges to the main structural members.

The truss arrangement offers a modern design solution that is consistent with other historic swing spans on the river and provides a defined gateway to the Bronx. The clean closed box truss members are detailed to minimize future maintenance needs, while features such as architectural fences and pier treatments are used to enhance the appearance of this significant bridge.

The project produced a range of social and economic benefits including essentially eliminating traffic impact during construction, improving highway safety and operations and providing a continuous, mile-long, 12-ft-wide bikeway/walkway on the bridge that interconnects the bike routes at both ends.

OwnerNew York City Department of

Transportation, New York

EngineerHardesty & Hanover, New York

general ContractorKiewit Constructors, Inc./Weeks

Marine Inc., a Joint Venture

Steel detailerTenca Steel Detailing, Quebec,

Canada (AISC Member)

30 JUNE 2014

At the grand opening of the Huey P. Long Bridge Wid-ening Project last June, Louisiana Secretary of Trans-portation and Development Sherri H. LeBas hailed the event as the rebirth of a great bridge, which symbolizes the continued rebirth of this great city.

Originally completed in 1935, the bridge was built to carry both rail and highway traffi c. At 23,000 ft between railroad abutments, the main spans of the bridge included two 18-ft highway travel lanes cantilevered off of the rail-road bridge.

After a study conducted determined that a new crossing was not a viable option, the Louisiana Department of Trans-portation and Development in 1986 began investigating wid-ening the existing span. Modjeski and Masters, the structural fi rm that designed the original Huey P. Long Bridge, was also engaged to design the expansion.

The fi nal approved design involved expanding lanes from two 9-ft lanes to three 11-ft lanes, with a 2-ft inside shoulder and an 8-ft outside shoulder. As an expansion of this magnitude was unprecedented, design teams faced

the additional challenge of executing an extensive analy-sis of the new main bridge superstructure, as well as the original bridge.

Construction for the massive project began in April 2006. The seven-year schedule was broken into four phases of construction, including: Phase I: Main Support Widening (piers) Began April

2006, completed end of May 2009. Prime contractor: Massman Construction Co.

Phase II: Railroad Modifi cations Began October 2006, completed June 2008. Prime Contractor: Boh Bros. Construction Co.

Phase III: Main Bridge Widening (truss) Began early 2008 completed July 2012. Contractor: MTI, a joint venture of Massman Construction Co., Traylor Brothers, Inc. and IHI, Inc.

Phase IV: New Approaches Construction Began June 2008 and concluded August 2013. Contractor: KMTC, a joint venture of Kiewit, Massman Construction Co., and Traylor Brothers, Inc.

PRIZE BRIDGE AWARD & SUSTAINABILITY COMMENDATIONReconstructed CategoryhuEY P. LOng bridgE, nEw OrLEanS

A span-by-span method of steel truss assembly and erection allowed the bridge to be widened without falsework in the river. Tom Macioce


During the first phase, river piers were widened from 60 ft to 80 ft by encasing the lower portion of existing piers with concrete. The encasements supported a new steel W frame that was in turn used to support the widen-ing trusses. The 53-ft-tall steel frame is 152 ft wide at the top but only 75 ft wide at its bearings. Once the steel W frame was supported, teams could widen the main river spans.

You can read more about this project in The Long Way Home (12/2012).

OwnerNew Orleans Public Belt Road Railroad,

New OrleansLouisiana Dept. of Transportation &

Development, Baton Rouge, La.

Program ManagersLouisiana Timed Managers, Baton Rouge

EngineerModjeski and Masters, Inc., New Orleans

general ContractorMTI, a joint venture of Massman

Construction Co., Traylor Brothers Inc., and IHI Inc.

Massman Construction CompanyKMTC, a joint venture of Kiewit,

Massman Construction Co., and Traylor Brothers, Inc.

Boh Brothers Construction

Steel TeamFabricators W&W/AFCO Steel, Little Rock, Ark. (AISC Member/NSBA Member/AISC Certified Fabricator)American Bridge Manufacturing, Reedsport, Ore. (AISC Member/NSBA Member/AISC Certified Fabricator)Industrial Steel Construction, Gary, Ind. (AISC Member/NSBA Member/AISC Certified Fabricator)Cosmec Inc., Athens, Texas (AISC Member/NSBA Member AISC Certified Fabricator)

Steel detailersCandraft Detailing Inc., New Westminster, B.C., Canada (AISC Member)Genifab Detailing and Engineering for Fabricators, Quebec, Canada (AISC Member)Tensor Engineering, Indian Harbour Beach, Fla. (AISC Member/NSBA Member)

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32 JUNE 2014

Residents of Ft. Worth now have an elegant new path over the Trinity River. Connecting Trinity Park to a new trail that terminates in downtown Fort Worth, the new Phyllis J. Til-ley Memorial Bridge has a graceful profi le that enhances the serene landscape. A steel arch with a span of 163 ft supports steel stress ribbon segments and precast concrete planks over the river, complementing the adjacent historic Lancast-er vehicular bridge.

The 368-ft-long, 12-ft-wide steel stressed ribbon/arch combination bridge is named for Phyllis Tilley, an advocate for use of the riverfront. Pedestrians and bicyclists cross-ing the bridge will experience a smooth, undulating ADA-compliant bridge surface. At night, the bridge is illuminated with a combination of white and blue LED lighting for in-creased safety and aesthetic appeal. The absence of verti-cal arch support struts reduces the horizontal loads created by periodic river fl ooding. The bridges slim profi le belies

the strength and versatility of the design, which enables the structure to sustain a 500-year fl ood event without raising fl ood elevations more than one inch.

One important challenge with stress ribbon bridges is achieving a deck running slope that meets ADA accessibility requirements and maximum allowable slopes. Since a stress ribbon bridge is in fact a catenary structure that derives its strength from the sag of the supporting ribbon, the deck slope must follow the sag of the ribbon, and this slope can easily ex-ceed ADA limits. To meet this challenge, the precast concrete deck panels were designed with varying thicknesses to provide a fi nished deck surface with a series of short ramps and land-ings that meet ADA requirements.

This bridge represents a cooperative funding effort by the City of Fort Worth, federal agencies and private donations through Streams and Valleys, Inc., a local not-for-profi t organi-zation that helps to protect and enhance the Trinity River and

PRIZE BRIDGE AWARDSpecial Purpose CategoryPhYLLiS J. TiLLEY MEMOriaL PEdESTrian bridgE, FOrT wOrTh, TExaS

The bridge is incredibly graceful, light and striking, enhancing the landscape and natural river and park environment.

Robert Healy


its adjacent trails. These groups invested a total of $2.5 million for a bridge that has already had a signifi cantly positive impact on the local area since its dedication in Au-gust 2012. The bridge is the fi rst pedes-trian crossing of the Clear Fork of the river in the last 20 years.

OwnerCity of Fort Worth, Texas

Engineer of recordFreese and Nichols, Inc., Fort Worth

Structural bridge EngineerSchlaich Bergermann and Partner, LP,

New York

architectRosales + Partners, Boston, Mass.

general ContractorRebcon, Inc., Dallas

Serving Our Customers Since 1981P.O. Box 1506 Pelham, Alabama 35124205.664.2950 800.868.6798 f: 205.663.3391www.centralsteelservice.com

BridgeSteelsHigh StrengthWeathering andHigh Strength

GRADESA588 A847

A572-50 A709-50A709-50W

PRODUCTSPLATES ANGLES

FFLATS CHANNELSROUNDS PIPE

SQUARES TUBING

34 JUNE 2014

The Sakonnet River Bridge carries R.I. Highway 24 over the Sakonnet River, a tidal passage separating the Town of Portsmouth on Aquidneck Island to the west and the Town of Tiverton on the mainland to the east.

Located just to the south of where the Sakonnet River opens into Mount Hope Bay, the Sakonnet River Bridge set-ting is one of mixed use, comprised of established neigh-borhoods with 19th and early 20th century homes, pleasure boat marinas, fishing wharves and commercial real estate.

The replacement structure accommodates two 12-ft lanes in each direction, 4-ft-wide high-speed shoulders, 10-ft-wide low-speed shoulders and a 13-ft-wide bicycle/pedestrian shared-use path on the north side of the bridge; this path introduces a pedestrian and bicycle connection between the two towns that has been absent for more than half a century.

After studying bridge types for the replacement struc-ture, it was decided that the most reasonable and prudent decision would be to design and advertise two separate structure types. These types included 1) an unpainted weathering steel trapezoidal box girder structure and 2) a twin segmental concrete trapezoidal box structure. Exten-sive architectural enhancements were included to dress up these economic structure types.

The final design has ten girder spans ranging from 100 ft to 400 ft. Several enhancements, including a boat ramp and handi-cap accessible fishing pier, were included in the contract. The project was advertised in October of 2008 and bidding opened the following January. The low bid was about $165 million for the steel alternative design, which was then constructed. Due to overlapping areas with the existing bridge, the new bridge was built in phases in order to maintain traffic at all times, and

four full lanes of traffic were operational on the new structure in September of 2012.

Ultimately, this bridge is noteworthy for its cost-effec-tive structure type, which is tastefully enhanced with archi-tectural and lighting features. In addition, innovative pile details allowed for combined side-friction and end-bear-ing in difficult soils, thereby minimizing driving depths. An incentive/disincentive program helped to fast-track the construction schedule, rendering the existing bridge out-of-service as soon as possible and lifting the heavy truck restrictions of this highway route. An automated electronic vibration and displacement instrumentation and alert system was attached to the existing bridge, and several of the existing piers were pre-outfitted for emer-gency jacking.

OwnerRhode Island Department of Transportation, Providence, R.I.

EngineerCommonwealth Engineers & Consultants, Inc.,

Providence, R.I.

general ContractorCardi Corporation, Warwick, R.I.

Steel Team

Fabricator Hirschfeld Industries - Bridge, Colfax, N.C. (AISC

Member/NSBA Member/AISC Certified Fabricator) detailer abs Structural Corporation, Melbourne, Fla. (AISC

Member/NSBA Member)

MERIT AWARDMajor Span CategorySakOnnET rivEr bridgE, TivErTOn and POrTSMOuTh, r.i.


The site of the Iowa Falls Bridge in Iowa Falls, Iowa, has seen a lot of action over the last century.The recently built bridge replaced a 1928

concrete arch bridge that had undergone seven rehabilitation efforts, including major ones in 1976 and 2000. Eventually, the origi-nal structure of the concrete span was found to be structurally deficient, functionally ob-solete and too costly to rehabilitate again. Although the structure was on the National Register of Historic Places, the Iowa DOT opted to demolish it and replace it with a modern steel bridge on the same alignment.

The arch rib used on this structure used a nearly square cross section rather than a rectangular configuration common with tra-ditional arch ribs. Consequently, the web plates near the base of the arch are thicker than normal. Conventional design practices use wind bracing between the arch ribs to minimize lateral bending forces in the arch rib as a result of wind loads perpendicular to the arch rib. However, due to the width-to-span ratio, a trussed bracing system was deemed inefficient and impractical. Instead, four struts were provided between the arch ribs to allow them to share the lateral loads, which required designing the arch ribs and struts for biaxial bending plus compression.

Redundancy was designed into the hanger cables and tiebacks at the abutment. In case of damage to the hanger cables, the cables were designed to accommodate full roadway traffic with any one of the four cables in a set removed or damaged. The tiebacks at the abutments are encased in HSS and grouted to add additional protection to withstand small impacts, such as those associated with light excavation equipment that might be used if the buried utilities off the end of the bridge had to be accessed. Also, by using lightweight backfill, the abutment was designed so the failure of one tie will not result in a progressive failure of the remaining ties in the abutment.

As part of its bridge infrastructure program, the Iowa DOT focuses on investigating the use of new high-performance materials, new design concepts and construction methods, and new maintenance methods. These progressive efforts are intended to increase the life span of bridges while also making them safer and more cost-effective. By increasing the longevity of the Iowa Falls Bridge and thus minimizing traffic disruption, the public will experience fewer construction-related travel delays moving forward.

MERIT AWARDLong Span CategoryiOwa FaLLS bridgE, iOwa FaLLS, ia

To achieve the greatest service life on the Iowa Falls Bridge, a number of corrosion-resisting systems were incorporated into the design. The struc-tural steel is A709 Grade 50 weathering steel. Areas exposed to road-salt spray and runoff are painted with a three-coat paint system to further protect the structure. The inside of the arch rib is also prime-coated for its entire length. The sockets, pins and threaded rods connecting the hanger cables to the arch rib and interior floor beams are galvanized. The cables have a Class A zinc coating on their interior strands and a Class C zinc coating on the exterior strands for additional corrosion protection.

The Iowa DOT testing and monitoring program, developed in coordina-tion with the Iowa State University Bridge Engineering Center, collects per-formance data for structures to compare against design-based structural parameters and to determine if the structural response is appropriate. Its most challenging research program has been related to developing structural health monitoring (SHM) to determine the real-time and continuous structural conditions of a bridge. For the Iowa Falls Bridge, the goal was to implement a multi-sensor continuous SHM system for general performance evaluation (structural, environmental, etc.) that can easily be adapted to other highway and interstate bridges and other monitoring needs. The system allows easy access to real-time data the Iowa DOT can react to immediately. To this end, a SHM system was developed by the BEC and placed on the bridge. Sensors monitor wind speed, potential icing conditions, traffic, heavy loads, corrosion, moisture, strain on the arch and cables and other conditions to help evaluate the performance of the structure, its materials and its long-term safety.

OwnerIowa Department of Transportation, Ames, Iowa

Engineer of recordHDR Engineering, Inc., Omaha, Neb.

general ContractorCramer and Associates, Grimes, Iowa

36 JUNE 2014

Just a few years ago, the Halsted Street Bridge over the Chicago River North Branch Canal put in its 100th year of service. Built in 1908, the movable double-leaf trunnion bascule

truss bridge provided navigable waterway accessibility for vessels too tall to pass beneath when it was closed. Due to the cost of maintaining a movable bridge and the lack of high-mast vessels using the canal, the movable mechanisms of the bridge were decommissioned over 25 years ago and the movable spans were locked together in the closed position.

More recently, the bridge became identified as the only remaining bottleneck to Halsted Street traffic and had become structurally obsolete (in 2007, it earned a sufficiency rating of 25.9 out of 100), and the Chicago Department of Transportation (CDOT) retained structural engineer Lochner to design a replacement.

The new replacement structure consists of a 157-ft-long, 80-ft-wide steel tied arch bridge main span flanked by two 36-ft three-sided precast concrete arch approach spans. With the new bridge deck 22-ft wider than the existing bridge, the replacement bridge carries two lanes each of northbound and southbound vehicular traffic, with one bike lane and pedestrian sidewalk placed on each side. Architectural enhancements were incorporated into the project, including architectural lighting and railings. The pleasantly wide sidewalks of the bridge are shielded from the vehicle traffic by cables and railings. This design arrangement provides the motorists as well as pedestrians with a much safer traffic environment.

To accommodate the roadway with four vehicular lanes and two bike lanes, the arch ribs are spaced at 60 ft. center-to-center; the rib element is a 2-ft, 6-in-wide by 3-ft-deep welded steel box. For simplicity, the rib is braced with a lateral system that consists of only four top struts rigidly

framed with the ribs. The interior of the tie girder is painted bright white for the convenience of future inspection via cameras through the hand holes.

The major force carrying cambered members also include arch ribs, ties and cable hangers. For the tied arch bridge, which is designed as a rigid moment frame in nature, member cambering not only serves to achieve a desired final bridge geometry, but also helps to reduce the member forces by injecting a counteracting force into the structural system through erection. Similar to the prestressing concept used for the concrete structure, introduction of the counteracting torsional moments imposed on the steel structural system allow the design to minimize the structural size and maximize the efficiency of the steel usage. Although the savings of the structural steel to the project was a direct benefit, additional indirect benefits included the use of lighter false work and reduction in demand for the crane capacity.

The original bridge was closed after Thanksgiving Day of 2010, and on Christmas Eve of 2011 the main construction of the project was complete and Halsted Street Bridge was open to vehicular and pedestrian traffic on schedule. The total final construction cost, including approach spans and roadway construction, was $13.7 million, well under the allocated city budget for the project.

The tied arch bridge is a valid design option for enhancing an urban setting with an aesthetically pleasing structure. The successfully completed project demonstrates that a short-span tied arch can be done economically with attention to the steel details that accommodate both accessibility and constructability. Plus, its size speaks to its adaptability and usefulness in tight quarters, and it validates that site issues can be overcome by thoughtful design.

For more on this project, see Chicago Crossing (06/2013).

MERIT AWARDMedium Span CategorynOrTh haLSTEd STrEET TiEd arCh bridgE, ChiCagO, iL


Steel Team Fabricator Hillsdale Fabricators, St. Louis

(AISC Member/AISC Certifi ed Fabricator)

Detailer Candraft Detailing, Inc., New

Westminster, B.C., Canada (AISC Member)

OwnerChicago Department of Transportation

Division of Engineering, Chicago

EngineersH.W. Lochner, Inc., ChicagoHBM Engineering, Hillside, Ill.

General ContractorWalsh Construction, Chicago

ICC-ES has published Evaluation Report ESR-3330 for designing Hollo-Bolt

connections to LRFD and ASD methods. This assures both building officials

and the wider building industry that Lindapters Original Expansion Bolt for

Structural Steel meets I-Code requirements.

Visit www.LindapterUSA.com to download the full Evaluation Report today.

Hollo-Bolt by

ICC-ES approvedfor compliance with the International Building Code

Exclusive Hollo-Bolt features include:

4 Highest resistance to tensile loading in accordance

with AC437

4 Use in Seismic Design Categories (SDC) A, B and C

4 Standard HDG product at standard pricing

4 Available off-the-shelf in sizes 5/16 - 3/4

from your local distributor

4 Patented High Clamping Force design

(sizes 5/8 and 3/4)ICC-ES Evaluation Reports are not to be construed as representing aesthetics or any other attributes not specifically addressed, nor are they to be construed as an endorsement of the subject of the report or a recommendation for its use. There is no warranty by ICC Evaluation Service, LLC, express or implied, as to any finding or other matter in this report, or as to any product covered by the report.

Copyright 2014 Page 1 of 61000

ICC-ES Evaluation Report ESR-3330Issued March 1, 2014

This report is subject to renewal March 1, 2015.

www.icc-es.org | (800) 423-6587 | (562) 699-0543 A Subsidiary of the International Code Council

DIVISION: 05 00 00METALS Section: 05 05 02METAL FASTENINGS

REPORT HOLDER:

LINDAPTER LINDSAY HOUSE, BRACKENBECK ROADBRADFORD, WEST YORKSHIREBD7 2NFUNITED KINGDOM 44 (0) 1274 521444 www.lindapter.comwww.lindapterusa.com

EVALUATION SUBJECT:

HOLLO-BOLT 3 PART AND HOLLO-BOLT 5 PART FASTENERS

1.0 EVALUATION SCOPE

Compliance with the following code:

2009 International Building Code (IBC)

Property evaluated:

Structural

2.0 USES

Hollo-Bolt Fasteners are designed for connecting structural steel to hollow structural section (HSS) steel members and other structural steel elements where access is difficult or restricted to one side only. Hollo-Bolt fasteners are intended for use with rectangular or square HSS members and are recognized for resisting static tension and shear loads in bearing-type connections. The fasteners are alternatives to bolts described in Section J3 of AISC 360, which is referenced in Section 2205.1 of the IBC, for bearing-type connections.

The Hollo-Bolt Fasteners may be used to resist wind loads, and seismic loads in Seismic Design Categories A, B and C.

3.0 DESCRIPTION

3.1 General:

Hollo-Bolt 3 Part Fasteners are assembled from three components, consisting of the core bolt, the body (sleeve) including the shoulder (collar), and the cone. The steel core bolt features a threaded shank and hexagonal head. The body is a steel segmented hollow cylinder, with four

slits 90 degrees from each other. The collar is a circular element having two flat surfaces (to accommodate an open-ended wrench) with a circular hole integral with the sleeve. The cone is a steel circular internally threaded nut with grooves on the outer surface. Nominal Hollo-Bolt sizes include 5/16 inch (M8), 3/8 inch (M10), 1/2 inch (M12), 5/8 inch (M16), and 3/4 inch (M20), with each size of bolt available in three lengths.

The Hollo-Bolt 5 Part Fasteners are similar, except that they include a nitrile rubber washer and separate collar. Figure 1 provides a picture of the Hollo-Bolt 3 Part and Hollo-Bolt 5 Part. Table 1 provides part codes, design strengths, and installation information.

3.2 Materials:

3.2.1 Set Screw: The core bolt is manufactured from steel complying with EN ISO 898-1, Class 8.8, having a specified Fu of 116,030 psi (800 MPa).

3.2.2 Body (sleeve) with Integral Collar, Body (sleeve without collar), Collar and Cone: The parts are manufactured from free cutting carbon steel Grade 11SMn30 or 11SMnPb30, conforming to BS EN 10087, having a minimum tensile strength of 62,400 psi (430N/mm2) (sizes up to LHB16) or 56,500 psi (390N/mm2) (size LHB20); or cold drawn steel AISI C10B21, having a minimum tensile strength of 68,000 psi (470N/mm2).

3.2.3 Rubber Washer: The shore hardness is measured on the A scale 80-90.

3.2.4 Finish Coating: All components, except the rubber washer, are hot dipped galvanized/high temperature galvanized to BS EN ISO 1461, as described in the quality documentation.

4.0 DESIGN AND INSTALLATION

4.1 Design:

The fasteners are alternatives to bolts described in Section J3 of AISC 360, which is referenced in Section 2205.1 of the IBC, for bearing-type connections. The design of the Hollo-Bolt Fasteners must comply with this report, Section J3 of AISC 360 and the strength design information for the Hollo-Bolt provided in Table 1 of this report. The load-carrying capacity of the assembly depends on the fasteners, the type of elements connected, such as a HSS and its their cross

ICC-ES Evaluation Reports are not to be construed as representingas an endorsement of the subject of the report or a recommendatito any finding or other matter in this report, or as to any product covered by the report.

2.0 USES

Hollo-Bolt Fasteners are designed for connecting structural steel to hollow stmembers and other structural steel elements where access is difficult or restricted to one side only. Hollo-Boltfasteners are intended for use with rectangular or square HSS members and are recognized for resisting static tension and shear loads in bearing-type connections. The fasteners are alternatives to of AISC 360, which is referenced in Section 2205.1 of the IBC, for bearing-type connections.

The Hollo-Bolt Fasteners loads, and seismic loads in Seismic Design A, B and C.

3.0 DESCRIPTION

3.1 General:

Hollo-Bolt 3 Part Fasteners are assembled from three 3 Part Fasteners are assembled from three components, consisting of the core bolt, the body (sleeve)including the shoulder core bolt features a threaded shank and hexagonal head. The body is a steel segmented hollow cylinder, with four

ICC

38 JUNE 2014

The Ramp TE bridge replacement covers a lot of ground (or at least spans over it).The project is part of the rehabilitation of the Alexander Hamilton Bridge complex on I-95, the Cross Bronx Expressway (CBE) between Amsterdam Avenue in New York County and Undercliff Avenue in Bronx County. The bridge supports the tightly curved Ramp TE over the West Approach span

Documents

Modern Steel Construction_june14