Value Engineering and Steel Economy

David T. Ricker

Value Enginee Engineering ring and Steel Economy

Author David T. Ricker graduated from the University of Connecticut in 1951 with a Bachelor of Science degree in Civil engineering. The following 12 years he was with American Bridge, except for military service. In 1963, he joined The Berlin Steel Construction Co., Inc. and has served as chief draftsman, chief engineer and currently as vice president-engineering. Ricker, active in AISC, ASCE and SSFNE, lectures periodically before these organizations and at several schools and universities. He has authored numerous articles on the practical aspects of structural steel fabrication and erection. He is a member of the AISC Committee on Manuals, Textbooks and Codes and the ASCE Committee on Design of Steel Building Structures.

Summary If the structural steel fabricating industry is to survive and thrive, it must stay competitive in the market-place. The cost of fabricated steel depends to a great extent on what the fabricator is required to do to the raw steel shapes and how he does it. Erectability is another significant factor in determining the cost of steel construction. This lecture will concentrate on the designer's role in creating a safe, economical structure for his client. In addition to such obvious cost savers as the elimination of overhead field welding and unnecessary stiffeners, there are many additional ways to enhance the value of the steel work. Quite often, a seemingly innocuous decision during the design stage can increase the steel quotations by thousands of dollars. If the designer designer is aware of cost-saving methods of steel construction, his client benefits in the long run. Sometimes, this may be the deciding factor in the selection of steel over competing materials. This lecture provides tips for economical steel construction and alerts designers to recent trends in design presentation resulting in huge increases in steel estimating costs.

© 2003 by American Institute39-1 of Steel Construction, Inc. All rights reserved.

VALUE ENGINEERING AND STEEL ECONOMY

By David T. Ricker, P. E. Vice Vice President - Engineerin Engin eering g The Berlin Steel Steel Construct Cons truction ion Company, Inc. Inc. Berlin, Connecticut

Designers who regularly practice value engineering consistantly

create the the best value for their client. client.

There Th ere are things which the

client can do for himself such as picking the right designer for

his project project, , clearly stating stating his goals goals and requir ement s, not changing is mind, and allowing ample time for design and construction. There Ther e are al also so things which a fabricator/erector can do to cut constructi constr uction on cost costs. s. But the party part y with the greatest greate st impact on the economic success of the project is the designer. Not only are the interests of the client directly in his hands but he also has a tremendous influence on the caliber of performance and monetary rewards of the other members of the construction team. Listed here are a number of things which a designer can do to enhance his design posture and assure that all parties concerned

benefit from the construction project.

1.

First, any designer desi gner wh who o wo work rks s in steel steel should take advantage of steel's many strong points: a. Good weight-to-strength weight-to-strength ra ratio tio. . b. The efficiency of of off-s f-site ite preassembly. preassembly . c. Speed Speed of deliver del ivery y and erection. erecti on. d. Steel is readil rea dily y available, availab le, can be stock piled and stored. sto red. e. Steel Steel has strength streng th in three directi dir ections ons. .

f.

Steel Ste el is elastic, elastic, versatile vers atile, , and du dura rabl ble. e.

g. h. i.

Maintains its its strength after after heating and yielding. yieldi ng. Steel Steel is easily wo rk rked ed . Steel Steel struct str ucture ures s can be added to to, , subtract subt racted ed from, altered, and reinforced to adapt to use changes. Steel Steel is compatible with other bu build ildin ing g materials. mater ials. Steel is easily inspected. Steel Steel design desi gn is user friendly frie ndly. .

j. k. l.

2.

A designer design er should keep cu curr rren ent t on the cos costs ts of the var iou ious s steel steel produc pro ducts ts he prescribes. prescri bes. Attached Atta ched to this article is is a list of mill extras expressed as a percent of increase above the base price pri ce of the steel steel at the mill. (Figure 1.) A steel fabricator can supply supply cu curre rrent nt base base prices. prices. The designers designer s should be aware of where the money is spent on steel constructi const ruction on - 50% 50% on material, materia l, 20 20% % on shop costs costs, , 20 20% % in erection, and 10% on other items such as drawings, painting, and shipping.

3.

A designe desi gner r should take advant adv antage age of allowable stress increases permitted by AISC Specification 1.5.6 for temporary loads such as earthquake earthqu ake and wind.

4.

Consider Cons ideratio ation n should be giv given en to th the e use of partial composite design of floor beams - something in the range of 50%

39-2

to 75%. Full composite design is inefficient. The cost of one shear stud in place equals the cost of approximately 7 pounds of steel. Unless this ratio can be attained the addition of more studs will prove uneconomical. 5.

Take advantage of live-load reductions if governing codes permit.

6.

Select a proper mix of A36 and high strength steels. High strength steels are advantageous when strength is the major design criteria. High strength steel (A572 Gr 50) is about 13% more costly than A36 steel but over 35% stronger. When deflection, stiffness, or some other serviceability criteria governs, the nod will often go to A36 steel because the heavier sections required will generally have a higher moment of inertia.

7.

Select optimum bay lengths. An exhaustive study by John Ruddy, P.E. (AISC Engineering Journal Vol. 20 #3, 1983) indicated that

a rectangular bay with a length-to-width ratio of approximately 1.25 to 1.50 was the most efficient. The filler members should span in the long direction with girder beams in the short direction. (Figure 2) 8.

Tailor the surface prepa ratio n and painting requirements to the project conditions - do not underdo nor overdo the coating requirements.

9.

Show all necessary loads on the design drawing to avoid costly overdesignin g of connections or dangerous underdesigning. This is an AISC specification requirement.

10.

Indicate who is responsible for "grey area" items such as loose lintels, masonry anchors, elevator sill angles, elevator sheeve beams, fastenings for precast concrete spandel panels, etc. Unless the responsibility is specifically delegated it is likely that the cost of these items will be included in the bids of 2 or more subcontractors, meaning the client may pay more than once for the same article.

11.

Don't require the steel subcontractor to perform work that should be done by other trades such as installing masonry anchors, ceiling hangars, lateral bracing for interior walls, toilet partition supports, window wall supports, and the like. Information required to perform this work is often slow to develop resulting in needless delay for the steel fabricator. The most efficient steel jobs are those on which the steel fabricator/erector is allowed to concentrate on the steel framework while unencumbered by the intricacies pertinent to the other trades. This reduces coordination requirements, and allows the steel framework to be turned over to the other

trades in far less time that would otherwise be possible.

12.

Consider the use of cantilevered rafters and purlins to save weight on roof design. (Figure 3.)

39-3

© 2003 by American Institute of Steel Construction, Inc. All rights reserved.

13.

Do not design for minimum weight alone. Such a design may require more pieces and more connections and will be more labor intensive in both the shop and the field.

14.

Excessively stringent mill fabrication and erection tolerances, beyond state-of-the-art construction practices, will probably reduce the number of bidders and raise the cost

to the owner. ASTM A6 tolerances and those established by the AWS and AISC have served the industry well and should be adhered to except under extraordinary circumstances where some special condition would dictate a more strict treatment. 15.

Designate the proper type of high strength bolt value. The correct application of each type is well documented in the current bolt specifications. Do not specify "friction" value for the purpose of obtaining an extra factor of safety.

16.

Allow the use of tension control (twist-off) high strength bolts. These bolts are as reliable as are other methods of measuring bolt tension and save labor costs.

17.

Where possible specify fillet welds rather than groove welds. Groove welds are more costly because of the joint preparation required and the generally greater volume of weld. (Figure 4.)

18.

Use single pass welds where possible.

19.

Favor the horizontal and flat welding positions. These welds are easier and quicker to make and are generally of a higher quality. (Figure 5.)

20.

Don't call for more weld than is necessary. Overwelding creates excessive heat which may contribute to warping and shrinkage of the members resulting in costly straightening expense.

21.

Grant the fabricator the option of eliminating some column splices. The cost of one column splice equals the cost of about 500# of A36 steel. The fabricator should study the situation carefully before he decides to omit the column splice and run the heavier shaft up to the next splice - the resulting column may be too long for safe erection.

22.

Avoid designing column splices at mid-story height. These are often too high for the erector to reach without rigging a float or scaffold. If the splice can be located no higher than 5'-0

above the tops of the steel beams it will save the expense of the extra rigging and still be in a region of the column where bending forces are relatively low.

23.

(Figure 6.)

Do not design column splices to "develop the full bending strength of the governing column size". Seldom is the splice located at the point of maximum bending and seldom do the bending stresses result in a condition which would require a full strength splice. The column has axial compressive

39-4


stresses. The excess capacity is allotted to bending stresses which occur as compression in one flange and tension in the the other flange. The compression forces are added to each other at one flange while at the other flange the tension force is subtracted from the compression force. Seldom does this other side of the column ever go into tension and never into full allowable tension of the magnitude that would require a full strength splice. Thus, there is little justification for ever req uiring a full strength column splice. (Figure 6.)

24.

Consider using a heavier column shaft or using a high strength steel to eliminate the need for web doubler plates and/or column stiffeners opposite the flanges of moment connected beams. One pair of stiffeners installed costs approximately the same as 250# of A36 steel if the stiffeners are fillet welded. If they must be groove welded the cost skyrockets to the equivalent of 1000# of A36 steel. The cost of one installed doubler plate is about the same as 325# of A36 steel. (Figure 7.) Considering that for an average two-floor column there could be as many as 4 pair of stiffeners and 2 doubler plates, at least 1750# of A36 steel (about 1550# of A572 Gr. 50 steel) could be sacrificed in order to save the time and expense of making the lighter shaft work. The value engineering should be done by the designer in such cases.

25.

Avoid designing heavy or awkward members in remote hard to reach portions of the structure. This may eliminate the need for larger more expensive hoisting equipment.

26.

Reinforce beam web penetrations only where necessary. The United States Steel Co. has prepared design aid booklets ADUSS 27-8532-01 and ADUSS 27-8482-02 which help to identify web penetrations which require reinforcing and also the amount of reinforcing necessary. It may be less costly to use a beam

with a heavier web, to move the opening to a less critical location, or to change the proportions of the opening to something less demanding. In any event, the value engineering should be done by the designer. (Figure 8.)

27.

For heavy bracing, where possible, translate the bracing work points so that they lie on the intersection of the flange faces rather than the centerline of members. (Figure 9.) Generally this will result in a more compact, efficient connection. (See article by William Thornton in the AISC Engineering Journal - Vol. 21, 3rd Quarter 1984.)

28.

Allow the prudent use of oversized holes and slots to facilitate fit-up and erection. They may eliminate or reduce the need for costly reaming of holes or refabrication.

29.

Specify that connection material be made of A36 steel including such items as column base plates and beam moment connection material even if the main members are of high strength steel. Allow the option of using high strength steel if the fabricator desires.

39-5


30.

Avoid calling for the indiscriminate use of stiffeners. Stiffeners are required to prevent local deformation or to transfer load from one part of a member to another. (Figure 10.) If the main members are capable of taking care of themselves then the cost of stiffeners can be saved.

31.

Avoid odd sections which may not be readily available or which are seldom rolled. These could result in costly delays.

32.

In areas of roof which are subject to snow drift loading arrange the purlins parallel to the drift and vary the spacing of the purlins so the same gage of roof deck can be used throughout. (Figure 11.)

33.

Space floor beams so as to avoid the necessity for shoring during the concrete pour. The cost of shoring is relatively expensive and can easily be offset by varying the span, gage, or depth of the floor deck.

34.

Avoid the "catch-all" like this: "Fabricate necessary to complete undoubtedly be padded This is unfair to the

35.

Avoid the "nebulous" specification which calls for stiffeners as required, roof frames as required, reinforcing of beam web penetrations as required, etc., etc. The fabricator/erector rarely has enough time to find out what is and what is not required therefore he will include in the bid an allowance for the questionable items whether or not they are eventually needed. Thus the client again coughs up the cost of something that may never be supplied. This is one reason why it is advantageous to all parties to make the design as complete as possible.

36.

Avoid the overly restrictive specification. The more restrictions listed in the steel specifications the greater the chances that no one will be able to meet them all. This will eliminate some of the competition and often result in higher bids.

specification which reads something and erect all steel shown or implied the steel framework." The bids will to cover whatever might be "implied". client.

When value engineering is performed by the designer the cost savings benefits go mainly to the client in the form of lower bids. When the value engineering is done by the fabricator/erector the cost savings is shared with the client, sometimes!

* * * * * * * * STEEL JOIST ECONOMY

The key to economical steel joist design is "standardization". Open web steel joists were originally conceived as single span members carrying uniform loads and as such they are at their best. Joists

39-6


are a standard product with relatively few variables. Departure from the standard will generally increase the cost of the joist. The following list of "do nots" will reveal some of these cost

risers. 1. 2. 3.

4. 5. 6. 7.

8. 9. 10. 11. 12.

13.

14. 15. 16. 17.

18. 19.

20. 21.

Do not specify non-standard joist depths. Do not call for non-parallel chords for "H" & "K" series joists. Do not specify severe top-chord slope for long span joists and joist girders.

Do not call for clip angles, brackets, or any such superficial attachments to be attached to the joist by the manufacturer as this would disrupt the normal handling and shipping system. Do not specify non-standard camber. Do not specify a special joist paint, surface preparation, or method of paint application. Do not specify a special paint color other than the standard brownish-red or grey. Do not prescribe a special paint thickness. Do not specify special chord or web sizes. Do not call for a special web profile.

Do not specify special material. The Steel Joist Institute (SJI) specification permits a broad range of acceptable material.

Do not stipulate hot rolled or cold rolled material to the exclusion of the other. The SJI specification permits both types. Do not prohibit or limit the number of joist chord splices, or to restrict the splice locations, or to require that the splice be made in a particular manner. The SJI prescribes splicing procedures which have passed the test of time.

Do not call for holes in highly stressed portions of joist chords.

Do not call for joist top chord extensions to be too long or too heavily loaded. Do not call for concentrated loads on joists which are beyond their capacity to resist. The SJI has established maximum limits. Do not specify bottom bearing joists if underslung ends will suffice. Do not call for cross-bridging where the SJI specification permits the use of horizontal bridging. Do not specify that the joist welds be made using a special

weld process or electrode. Do not indicate "ceiling extensions" if the ceiling is "hung" below the joist.

Do not require that modest concentrated loads be delivered at a panel point. A joist top chord is designed to support a 400# load anywhere between panel points in addition to the normal uniform load.

Attention paid to these small items will result in substantial joist economy.

39-7


There are other ways to realize cost savings in joist construction. Sometimes it is less expensive to use a heavier joist if it reduces the bridging requirements. (Figure 12.) Bridgi ng installation is ve ry labor intensive. For example, a 12K1 joist 17'-0 long requires 2 lines of bridging whereas a 12K3 joist of the same length requires only 1 line of bridging. This is a 50% reduct ion in bri dgi ng and the cost of the heavier joist is only about $3.00 more. When a span is so short as to make it impractical or impossible to use an open web joist, a joist substitute can be used, such as angles, channels, small wideflange, tubes or combinations thereof. Figure 13 shows limits for minimum lengths of short joists. Figure 14 shows some of the shapes which can be utilized as "short joists".

* * * * * * * METAL DECK ECONOMY

Formed metal deck for floors and roofs plays a significant role in steel building construction. There are enough variables in deck design to make it important for designers to put the right combination together so that the client will receive full value. Listed here are some of the variables. 1. 2.

3. 4. 5.

Type: roof deck, floor form Profile: na rr ow , intermediate, wide Depth Gage. Finish.

6. 7.

Side laps. End laps,

8.

Span, stress, and deflection. Fastening Systems.

9.

Roof Deck Roof deck is available generally in 1-1/2" and 3" depths, (special deeper deck is available from a few manufacturers), in gages from 16 ga. through 22 ga., and with painted, G60 galvanized, or G90 galvanized finishes. Roof deck is available in accoustic and non-accoustic styles, with or without cells. Three profiles are available - narrow, intermediate, and wide-rib. Side laps are either nestable or interlocking. (Figure 15.) Deck ends are usually overlapped for a minimum of 2". Die set (swaged) ends were offered at one time as an aid to deck nesting but modern deck profiles are such that this is no longer necessary. In fact, there are distinct disadvantages affecting the erectability of deck panels which have die set ends. The span is important because it has a direct effect on several other deck properties, namely the profile, gage, depth, stress, and deflection limits. Narrow rib deck is so inefficient that it is seldom used. Intermediate-rib deck is less expensive, generally, than wide-rib deck. (Intermediate deck is offered in 24 ga. by some manufacturers.) For a given span and gage, wide-rib is stronger than intermediate-rib which, in turn , is stronger than narrow-rib roof deck. As a rule thick deck costs more than thin deck all things being equal, and 3" deck costs more than 1-1/2" roof deck.

39-8


Generally G90 galvanized deck costs more than G60 galvanized deck

which, in tur n, costs more than painted roof deck. Some deck manufacturers offer other finishes such as electro-galvanized, phosphorized, and galvanized/painted, which may be cost-affective. On occasion a manufacturer may offer a special price on a certain type of finish. The availability of the specified product should be checked prior to finalizing the deck selection.

This brings up a pertinent point. Often specifications are written listing several acceptable deck manufacturers. As some of you have no doubt found out, the deck industry is very volatile. Not only do deck companies come and go, but the products they offer are apt to vary from time-to-time. Also, some companies only ma rk et their product in certain parts of the nation. It is nearly impossible for a designer to keep track of all the changes. It is perhaps more effective merely to stipulate that the deck manufacturer must be a member in good standing of the Steel Deck Institute (SDI) or to prove in some other manner that he knows what he is doing. ********

The following example of value engineering will illustrate how the various deck variables can be selected in order to provide the client a suitable product at a fair price: It is required to provide metal roof deck for a large warehouse. The engineer has made several efficiency and cost studies and has determined that a wide rib, 20 ga., 1-1/2" deep deck on a seven foot 3-span condition meets his requirements for load carrying ability and deflection. He selected the wide-rib deck because, had he used intermediate rib, it would have required an 18 ga. thickness. Narrow rib was not considered because the span would have been so short that it would have required many more supporting members. Three-inch deep deck was considered and the span could have been increased to 10'-0 and the deck lightened to 22 ga., however the supporting members increased in size and did not fit in well with the bay width of 35'-0. 20 gage deck is amongst the most commonly

used. Most manufacturers carry a stock of 20 and 22 gage coils resulting in good availability and quick delivery. Painted deck was selected because the interior of the building is dry, well ventilated, and not subject to corrosive atmosphere, condensation,

dampness, or any other condition that would have required a more expensive coating. The Engineer needed some diaphram strength from his deck system so he selected a deck with nestable side laps rather than interlocking side laps. Interlocking side laps are normally fastened with a button punching device and this method is unreliable

in transmitting diaphragm shear forces. Nestable side laps can be welded, screwed, or pop riveted. In 20 and 22 gage deck there is a danger of blow-throughs when welding side laps so a self-drilling

screw system was selected. Plain rather than die-set panel ends were stipulated. There was no reason to requ ire die-set ends. The probability existed that the deck might have to be laid in a patchwork manner and die-set ends would have created a severe hardship for the erectors since die-set deck is ordinarily laid out end-to-end all in one direction from one end of the building to the

39-9


other. The deck was supported by members which had relatively thick flanges. For this reason it was felt that welding would be the most efficient manner of fastening. (Figure 16) If the supporting material had been thinner, screw type or power-driven fasteners would have been considered. As it was, the Engineer did wisely permit all three methods in his specification. Since the deck was thicker than 0.028", weld washers were not needed nor specified. * * * * * * * * The previous scenario is typical of the deck selection process used by many designers. Note that unnecessary features were not specified such as galvanizing, die-set ends, weld washers, accoustic treatment, cell-deck, insulation clips, ceiling hanger s, or restrictive erection procedure. The end result is a roof deck no more expensive than it has to be and which will fulfill the design and performance requirements. * * * * * * * * Floor Deck

Similar economical advantages can be realized in the selection of floor deck. Floor deck for the support of poured-in-place concrete is available in several styles - form deck (centering) which usually comes in a modified corrugated profile varying in nominal depth from 1/2" to 1-1/4", composite (deformed) floor deck, cellular deck, deck for use with shear studs, deck which cannot be used with shear studs, vented or unvented deck, and deck with provisions for hanging ceilings. (Figure 17) Deck is available in 1-1/2, 2, and 3" depths and some manuf actur ers have special deeper decks. Inverted roof deck can be utilized as a form for placing wet concrete. Floor deck is available in gages from 16 to 28 depending upon the type selected. It is available in uncoated, galvanized, phosphatized, painted, and certain combinations, again depending upon the manufacturer and type of deck. Floor deck comes with either nestable or interlocking side

laps, depending on the type and manufacturer. As with roof deck there are many variables amongst floor deck features, enough so that careful selection must be made in order to assure that the client receives maximum value. The cost conscious designer will only specify those features which he deems necessary to proper performance and will reject unnecessary requirements which serve no particular purpose in his structure. If he does a good job chances are the deck bids will be as low as possible. * * * * * * * * TUBE AND PIPE ECONOMY

Tubes and pipes make economical column members. They are an excellent choice when stiffness about both axes is required. They can be used as hollow members or filled with concrete. There is no

39-10


great strength advantage to filling small tubes or pipe with concrete. A TS3x3x1/4x10'0 has a capacity of 37k when filled with concrete and 33k when unfilled. For larger columns there is an advantage to adding concrete filling. For example, a pipe 8" standard column 12 feet long has a capacity when filled with 3000 psi concrete of 217k whereas the unfilled capacity is only 155k. Tubes and pipes have less surface area than equivalent wideflange members. For example listed here are the surface areas per linear foot of three common sizes: W8x31 = 3.89 sq. ft. TS8x8x1/4 = 2.65 sq. ft.

pipe 8 std = 2.26 sq. ft. This can be a significant cost factor if the members require an exotic surface coating or fire proffing.

Tubes offer excellent resistance to torsional forces and can be used to support eccentric loads such as relieving angles for brick veneer, stone, or precast concrete. (Figure 18) Tubes also make efficient bracing members. Figure 19 shows various methods of connecting tube and pipe members. They can also be combined with other structural shapes to produce some startling

aesthetic effects.

(Figure 20.)

In recent years tube and pipe prices have become more competitve. Availability is sometimes a questionmark - a fabricator or supplier should be consulted. * * * * * * * * UNECONOMICAL DESIGN PRACTICES

A goodly portion of the fabricator's overhead expense is spent on

estimating. For every job he gets he may make 10 to 20 unsuccessful attempts. Some recent project specifications have been written in such as way as to require the fabricator to complete significant

portions of the steel design in order to prepare an accurate cost estimate. Here are some examples:

1.

"Metal roof deck shall be designed by the metal deck contractor. Dead load is 25 psf. Live load to be in accordance with local applicable building codes. Maximum live load deflection is L/240. Drift loading shall be taken into consideration. The decking contractor shall coordinate all roof opening sizes and locations and shall design and provide headers as required. Minimum deck thickness is 20 ga."

2.

"Metal floor deck shall be designed by the metal deck contractor without shoring to carry the weight of the wet concrete plus a temporary load of 20 psf or a concentrated load of 150# on a one foot width of deck, whichever results in a heavier deck. Deflection is limited to L/180 or 3/4" whichever is the

39-11


smaller. If shoring is required at thickened slabs or tapered ramps the deck contractor will determine the need for shoring and design and provide the shoring as required. Minimum floor deck thickness is 20 ga." 3.

"All floor beam and gi rder connections shall be at least strong enough to develop the end reaction of the uniformly loaded member considered fully composite. The end reaction of all beams and girders shall be calculated from the current AISC Manual of Steel Construction "Uniform Load Constant Table" multiplied by the ratio Str/S to account for the composite construction. The connection design shall also consider all concentrated loads acting on the member." (No loads given.)

4.

"Provide welded stiffener plates on both sides of the beam web at points of concentrated loads." (No loads given.)

5.

"At tower wind bracing connect for the full compression capacity of the member or 50% of the tension capacity, whichever is greater." (No load given.)

6.

"All beams and gi rd er s framing to columns shall have connections designed for a horizontal bracing force on both ends equal to 1% of the maximum allowable load on the column. The maximum load on the column = 0.6 Fy A where A equals the gross area of

the column."

(No loads given.)

7.

"Provide web doubler plates as required at all beams and columns where shear loads are beyond the capacity of the member."

8.

"Provide column stiffeners as required at all column moment connections where the beam flange forces are beyond the capacity of the column member."

9.

"Verify the stud shear capacity with the type and brand of floor deck supplied. The number of studs shown on the design is based on N=9 and a stud capacity of 11.5k. Adjust the quantity of studs shown on the design if the stud capacity differs from that given above."

10.

"Design column base plates for the full capacity of the column using the procedure given in the current AISC Manual of Steel Construction. Design beam bearing plates for the full capacity of the beam at the given span." (No loads given in either case.) * * * * * * * *

These are but 10 examples in which a considerable amount of additional design work must be done by the fabricator before he can produce an accurate estimate of his costs. If 8 fabricators are pursuing a particular project the additional design work would be repeated 8 times. This duplication of effort is a shameful waste of America's time and energy. It will boost estimating costs and this

39-12


will eventually be passed on to the client. The time consumed will undermine one of steel's strong points - speed of delivery. The fabricator who elects to bypass the necessary design investigations may end up in deep trouble with a bid and a job that is much too low. If he loads his bid to cover "worst case" conditions the chances are he will not get the job. If all bid der s elect to pad the bids the client ends up paying more than he should. When a fabricator has to determine loads via analysis of the member the results will often be unrealistic. If the member was designed based on stiffness, aethetics, minimum thickness requirements, or deflection, this information is not normally known by the analyser. The resulting connection may be designed for a load that is many times greater than the actual load. This is uneconomical for the client. Worse yet it may result, over the long haul, in a shift by some designers from steel to some other material because their steel designs are consistently expensive. We certainly don't want this to happen. Fortunately for the steel industry. These practices are not universal. The separating of design duties will further complicate the question of design responsibility. Those who continue to fan the flames for split responsibility will have a field day with this situation. The unfortunate result is that the cost of steel construction will be driven upwards at a time when the steel fabricating industry is locked in a serious effort to stay competitive. To hold the line it is essential that fabricators and designers cooperate to the fullest

extent possible.

* * * * * * * THE END * * * * * * *

David T. Ricker June, 1988

39-13


MILL EXTRAS

Percent increase above base price*

Light sections.......WF.................................. 10% Medium sections......WF.................................. 17% Heavy sections.......WF.................................. 24% Standard beams................Higher Base Price.......... 13% Standard channels........................................ 9% Miscellaneous channels................................... 17% Standard angles.......................................... 14% Cut lengths <10'........................................ Inquire 10' to 20'................................. 20' to 30'................................. 30' to 40'. ..... .... ..... .... ..... ..... .... 40' ............... ............ ............

40' to 50'................................. 50' ....................................... 50' to 60'................................. 60' .......................................

>60' ....................................... Quantity >10k. .......................................... < 1k ..........................................

A572-50 ................................................. A588 .................................................... Chemistry (Special ingredients or amounts)............... End milling ............................................. Splitting tees .......................................... Cambering ...............................................

*

9% 5% 1% 0 1% 0 1% 0 6% 0 23% 13% 35%

varies 16% 12% 12%

These percentages are general in nature, vary between suppliers and are subject to other variations. FIGURE

1

FIGURE

2

39-14 © 2003 by American Institute of Steel Construction, Inc. All rights reserved.

FIGURE

3

FIGURE

39-15

4


FIGURE

FIGURE

39-16

5

6


FIGURE

7

FIGURE

8


FIGURE

9

FIGURE 10

39-18


FIGURE11

FIGURE

12


FI GU RE

FIGURE

13

14


FIGURE

FIGURE

15

16


FIGURE

17

F I GU R E 18

39-22


FIGURE

FIGURE

39-23

19

20


Value Engineering and Steel Economy

Recommend Documents