Arc Welding in the Building Industry J. F. LIYCOLN, The Lincoln Electrir Company, Cleveland, Ohio
procebs not only eliminate- iiiterrnediate b t r u c t u r a1 members altogether, but i t also does away Rith punching the two members that remain. Prior to the discovery of the shielded arc process of welding, which introduced a neJT era in the art of joining metals, arc welding, while possessing inherent simplicity, did not provide the high quality of welds, high welding speeds, and low costs of welding which were needed to bring arc welding to the full hlooni of its possibilities. With the advent of the qhielded arc, tenrile itrength of weld metal rose from between 40,000 and 50,000 pounds per square inch to between 6t5,000 and 85,000 pounds. Ductility of the weld metal was niore than doubled. Density of weld metal produced in a shielded arc became 7.82 to 7.86 grams per cc. whereas, before, it had been 7.5 to 7.7 grams. Similar improvement was noted in the fatigue and impact r e s i s t a n c e of shielded arc weld metal. The former rose from 12,00015,000 pounds per square iiich to 28,000-32,000 pounds. The latter jumped from 8-15 foot-pounds (Izod) to 50-80 foot-pounds. Shielded arc weld metal is cLqual to mild rolled steel in its resistance to corrosion arid in all other respects, and its tensile strength is from I 3 to over 25 per cent greater than that of steel.
Bridge and Building Construction Bridge designers are becoining iiiore ant1 more mindful of the economies permitted by nelding structural menibers with the electric arc. A rerent ilesiqn of a through-truss highway bridge indicated a savings of 15 per cent over what it would have cost to build the bridge by rireting. Approximately 12.5 per cent less .tructural steel was required. In addition, the total dead load of the hridge wa- retlucerl 3.3 per cent.
T
HE use ui' arc welding as a manufacturing, c o n s t r uction, and niaiiiteiiance tool has increased remarkably in r e c e n t y e a r s . This widespread adoption of the process has been due to definite economies which it provides and to marked improvement in t,he products so manufact'ured. The one great fundamental advantage of arc welding is its extreme simplicity. This simplicity is inherent because a r c w e l d i n g eliminates extra parts which are necessary in other processes. Two structmal members are joined directly to each other without the use of a third or connecting member. This direct application permits extensive savings not only in materials, but also in designing, detailing, and handling. Prbbably t'he greatest economy achieved by arc eld ding is savings in m a t e r i a 1s . This amounts to 15 per cent and more in buildings so designed to date. By t'he very fact that arc welding sares materials, i t also reduces fabricating costs, since the number of separate pieces in any structure determines the number of handlings during assembly. Detailing is simplified. No p u n c h i n g of c o n n e c t i n g members is required in arc weltling. This
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Arc lvelding is used extensively in strengthening bridges. The use of the elect'ric arc has saved thousands of st'ructures which otherwise n-ould have required replacement. Corroded and cracked bridge parts have been replaced, and additional strength, necessitated by increased loads, ha> been provided by welding in new reinforcing members. Floor beams are strengthened by welding on cover plates arid well stiffener plates. Stringer flanges are strengthened by n-elcling in plate stiffeners. Corroded column footings, girder or truss bearings, piers or abutments, etc., are repaired by arc welding. The ability of the electric arc t o fuse new metal to old has made it possible to continue in service many bridges which otherwise would have required replacement. N a n y schools and other buildings in earthquake areas have been strengthened by arc Tvelding. Twenty-nine California schools, eighteen in the San Francisco Bay region and eleven in the southern part of the state, have been strengthened. The high tensile strength provided by shielded arc welding more than met specified requireLLientsfor this work. Actual evidence of the increased earthquake resistance provided t,o buildings by arc welding is furnished b y the Los Angeles Building of the Southern California Edisoii Conipany which has passed through several quakes without being damaged. This thirteen-story structure was completed in 1931 and was provided with arc welded earthquake bracing.
Arc-Welded Frames for Private Dwellings Among a number of steel frame houses erected recently b y arc welding, a twelve-room residence built a t Toledo during the past suninier bespeaks the future possibilities of arc welded steel in dwelling construction. The use of arc welding in erecting the frameivork reduced the cost of steel construction
to a par with wood, whereas former jobs of steel construction have figured at 8 to 19 per cent inore than wood. Thus the arc welding provides t'he home owner with all the advantages of a steel frame dn-elling-fireproof construction and greater perinanence-for no niore than he would pay for ~ ~ o o c l . In building the Toledo residence, every possible advantage was taken of arc welding. It was used to reduce the nuinlier of pieces to he handled during erection by asseiiibling the entire wall framework in forty-five panels. These panels were delivered t o the building site ready for erection. Erecting the franien-ork was simplicity itself. The only equipment used was an A-frame and an arc welding machine. I n place of the usual "rat-tat-tat" of the riveting hammers, the only noise which could be heard-and this was only within a few feet of the work-was a steady hiss of the electric arc.
Future of Arc Welding Arc welding, because of the reduced erection costs which it makes possible, will become more widely used as work in the building industry is resumed. The many advantages of the process nil1 be appreciated by architect, contractor, arid owner. Especially in the field of residence Construction will arc n-elding be used to great advantage. The designer \vi11 be eiiahled to produce on his drafting table a drawing for any type of architecture with complete assurance that the contractor can secure any desired result with arc welding. I n turn, the contractor, working with the electric arc, will profit in reduced time and labor costs through use of this fast-workiiig erection tool. And last, but far from least, the owner of the residence will have-for the price of woocl-all the aclvantages of a steel framed home. RECEITEDApril 27, 1935.
Synthetic Plastics J
CH.IRLES A . R R E S l i I ~ 1Iodern . Plastics. New 1 o r k . S . Y.
Qualities Requisite for a Building Jlaterial ELIEVISC; that the proceFh of adapting a new inaterial is gradual rather than revoThe following qualities are requihite for a tiuildiiig nialutionary, t'he plasbics industry ha-. placed terial, and the pla*tic>,a i a group, po.\e+ the-e in unusually empllasis on laboratory derelopment, practical tebtillg, experimental installations. a result of thi. procedure, large nleas"re: plastics of certain types are today wide . used by architect-, (1) CGXP.LR.YI.IIELT LO\T. COST. In a study recently made by engineers, and builderb as true and tandard material>-one ~ , ~ i itl d ~ ~found that lanlinated plastics, of the type knon-n coninionly as Formica or Micarta, were almost cheap better for their purpose than any others. In m o d indancethe thought is never elltertail1ed that liere is soniething re1-oenough, even with today's comparatively limited production, f o replace plaster, lathe, and paint for interior walls and ceillutionary. Plastics in their more colllllloIl bUC], ings. Again, the wide and growing number of instances in which a i electrical fixtures, door knobs, wall surface;, store fronts: fronts, store and lobby such laminations have heen for etc., are accepted as a coninion part of the inaterials ai-ailahle interiors, table top,, willsl doors, and toilet stalls, bears testimony to the already existing comfor the builders' selection. petitive p o s i t i o n of the lamiYet ~vithinthe plastic family ntited plastics, particularly when lie possibilities for the archiThe properties of the various g r o u p of thev replace m a r b l e , metal, or tect,,engineer, and builder which svnthetic ticj are o L ~tlined and their highly decorated plaster. are only today being opened u p ( 2 ) L.\RGE A S D C O X S T A S T laminated form i j suggejted for paneling SOURCE OF R.~IIL~ATERI~LS. -possibilities fully as r e v o l u and ciecorative work. \Iolrle[i uses for Here ~ a i the n ~ n t h e t i opl'stic* tiollary as any nlentioned for offer a d v a n t a g e s . T h e y a r e other, shall we say, "mythical" electrical fittings and huilding accessorie? part and parcel of America's great m a t e r i a l s . T h a t the Po--iare oLitlilledt arid phen,,,lics for lighting chemical i n d u i . t r y . The materials from which they are made bilitieJ are to fulfilhllellt fixtures a n d general decorative appliances have shonn a n e x t r e m e l y low i n due in large part t o the con1 comparison of properties factor O f price fluctuation O v e r a are discussea. servative research attitude of long period of years. The plastic* with those of other materials and examples industry can meet any rensonahle the plastics i n d u s t r y a n d ill large part, to the inherent qualiof actual installations which have proved ~ ~ > ~ ~ ~ ~ danget' ~ ~ ~ ? ties of synthetic pla.tic< theintheir worth are included. (3) STRUCTVR.AL QCALITIE~. selves. Here t h e p l l l s t i c s n1u.t h e
