PRESTRESSED CONCRETE INSTITUTE

Pubbshed Monthly by the

PRESTRESSED CONCRETE INSTITUTE January 1961Vol. 7, No. 1

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fee erec~~0hl~ c. Gerw~ Inc. •IOO ft. S~ng~e

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Son Vel Concrete Corp.StreS5t~~~;sed arches.

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Cement Co., BenC~~’ ne ~~ght for Californiaperman~.dge beamsBr’

Tower Crane, Ilford, England.Cement and Concrete Assoc

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Handling And ErectingPrestressed Concrete Members

The correct fabrication of a precastprestressed member is only one step inthe procedure towards it’s proper application. The member must also he correctly handled and properly installed. Whilethe proper handling and erection of astructural system is usually taken forgranted by the engineer or architect somemay never-the-less be a bit apprehensive.The hauling and erection of precast prestressed members requires ordinaryhandling care. Once erection contractorsbecome familiar with prestressed concrete they think of it in the same way asthey do any other prefabricated member,whether made of steel, wood, or aluminum. Enough experience has now beengained in handling prestressed concretethat even jobs requiring very long andheavy members have become commonplace.

Plant handling of members is largelya matter of economy as far as the producer is concerned. The present methodsof handling prestressed members in theplant employ equipment such as fork lifttrucks, straddle carriers, motor cranes,gantry cranes ~*rail and rubber tired),overhead or bridge cranes, whirleys, side

boom tractors, and various custom rigs.Each producer determines the best system to fit his production schedule andplant ]ayout. Our discussion and pictorialpresentation will center chiefly on thevarious methods used to move the material to the job site and place it in itsfinal position in the structure.

During the erection period the structure is often in an unstable condition asthe final method of connection is usuallynot complete. The engineer or architectshould provide an initial connection thatis both simply and quickly accomplishedand yet safe and adequate to handlereasonably expected erection loads. Itis advantageous to design this initialconnection with ample tolerances. Additional means of providing for a safe structure during erection are temj,orarybracing and guy wires. All of these methods must be considered if the structureis to be safe until! the time when the finalconnections can be accomplished.

Considerable thought has gone into thedesign of special equipment which nowmakes most handling and erecting jobsa simple matter. New equipment andmethods are constanfly being developed.

The photographs included with this article illustrate many common methodsused to safely transport and erect prestressed members.

Various ingenious precedures havebeen developed for erecting precast prestressed members for multi-story buildings. See photos Page 4. These methodsprovide safe, economical means by whichprestressed members can be placed regardless of the number of stories or sixeof floor area.

The important factors to consider whenhandling prestressed members are thatthey be lifted near their support pointsand in a vertical position. Special consideration should be given to long slendermembers to insure that they are handledwithout danger of buckling. Although asthe many photographs presented heretestify this is not as troublesome as maybe imagined. Sometimes it is necessaryto increase the lateral stiffness with bow-like trusses or steel frames.

In summary—if careful thought isgiven to the hauling and erection techniques, coupled with an intelligent approach to temporary erection condition—precast prestressed members can bused in almost any situation.

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Nebraska Prestressed Concrete Co.Erection of 96 ft. AASHO Type gir ers for Waverly Nebraska HighSchool. Note correct erection procedures with proper guying and struting.

Superior Sand and Grovel

Standard Glass Co. Office building, Phoenix, Arizona,built entirely of prestressed members. Note ample bracing used during erection.

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MEANS OF TRANSPORTING AND ERECTINGPRESTRESSED MEMBERS

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Precast lndi,stries Inc.Method of easily loading prestressed members for rail transportation.

Food Machinery and Chemical Corp.Transporting of 104 ft. bridge beams by truck, featuring arear end steering unit

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Sika Chemical Corp.Straddle carriers hauling bridge beams for Garden State Parkway.

Empire Pre.Stress Concrete of OregonLoading girders for shipment by boat to Kenai River BridgeProject in Alaska.

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Vacuum ing mat used to erect prestressed deck~members.The Prescon Corp.

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Self-clamping cart developed by Associated Sand and GravelCo., Everett Washington for handling long girders.

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Superior Sand & GravelSimilar gantry rig method used in placing prestressed membersfor a roof over an existing two story building in a Phoenixshopping center.

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Contractors & Engineers MagazinePlacing precast prestressed beams for a 25 story Hawaiian officebuilding using dollies riding on large rubber tired casters. Beam islowered by hand operated winches.

Electric powered Tower Crane recently developed by Bucyrus—Ere Co.use on multi.story building erection. With its adjustable, building-he~j’tower and 60 to 120 ft. boom lengths the crane provides both vertical a$~-...horizontal lifting ability in one continuous cycle. The Ilford cover pictureillustrates an English tower crane in operation.

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Blakeslee PrestressMethod used to erect prestressed members over existing 3floor Springfield, Massachusetts, parking garage. Crane liftsprestressed members to roof where gantry type rig takesgirders and places them.

METHODS USED INMULTI-STORY CONSTRUCTION

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Blakeslee PrestressClose up of gantry rig used at Springfield parking garage.

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ERECTING LARGE BRIDGE MEMBERS

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Nebraska Prestressec! Conc. Co.Gantry built to pick up the 110 ft. girders direct from railroad flatcars and place them on their pier bearings. Platte River, Nebraska.

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Closeup ‘of the gantry and truss built to carry thegirders to the adjacent piers.

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Concrete Pipe Company of Ohio Inc.94 ft. bridge beams were placed by floating one endacross on a barge while a land based crane supportedthe other end.

4emeM4fWRITE FOR CATALOG

SUPREME PRODUCTS CORPORATION2222 S. Calumet Avenue, Chicago 16, Illinois

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• AASHO DISCUSSES PRESTRESSEDCONCRETE AT ANNUALMEETING

Last month AASH@ held its 46th annual meeting in Detroit, M.ft~higan andCharles C. Zollman, P€~I representativeto AASHO, attended the bridge committee sessions. At these meetings problemsare discussed by bridge engineers andwhenever necessary written recommendations are prepared by the chairman forsubsequent submittal to Committee members for their study and approval. Theserecommenda~ons are not incorporatedinto official AASHO documents untilthey are approved by ballot.

Some of the discussions pertained toprestressed concrete. The results of- astudy concerning the omission, of blocksin pretensioned beams was presented• by

• Mr. William E. Dean, Jr., Assisfant High~way Engineer ~StructTffèI’~ of’the St~té

df Florida. A proposed specffication wassubmitted providing a basis for determining the required mild steel reinforcingin the end zones when end blocks areomitted.

John N. Clany, Bridge Engineer forthe Commonwealth of Virginia andChairman of the Joint AASHO-PCI Committee on Prestressed Piles made a presentation on proposed standards for pretensioned concrete piles. Preliminarydrawings were distributed to BridgeCommittee members for discussion. As aresult Mr. Clary scheduled completion of the work byThis committee onproposed standards early this year. Theywill then be submitted to the full AASHOBridge Committee before their Springregional meetings.

Richard S. Fountain, Bridge Engineerof the Portland Cement Association, pre—serited a paper entitled “Field Inspection of Prestressed Concrete Bridges.”This report concerned the structural be-

havior of prestressed concrete bridges invarious parts of the country, and suggested measures to be taken to correctminor deficiencies.

A question of tinie lapse between concrete placing and detensioning was alsoraised. Considerable discussion centeredaround the question as to whetherstrength of time governs at detensioning.This may also appear on the agenda ofthe regional meetings.

There was also a report on the elimination of shear keys between a precastbeam and a composite slab. The amountof allowable bond stress between thebeam and slab was also discussed.

MEMBERSHIP APPLICMIONSAPPROVED BY BOARD

AeTIIVEEAU CLAIRE STRESSCRETE, INC..

1~59~Menômonie”Street -. = -

Eau €~laire, WisconsinWilliam W. Tucker

F. H~LBUT CO.1-33 Cedar St. -

Green Bay, WisconsinC. H. Bennett

ROSS ISLAND SAND & GRAVEL CO.4129 S. E. McLoughlin Blvd.Portland 2, OregonW. H. Muirhead

PROFESSIONALALFREDO APARICIO

Carrera 7 #55-59Bogota, Colombia, S. A.

EDWARD R. BUNNELL632 Rosemarie Ave.Norfolk 2, Virginia

STANLEY H. COOPER8 Spadina Rd.Toronto, Ontario, Canada

SAL V. DE SIMONE415 Madison Ave.New York, New York

J. NELSON HICKS221 Conyngham Ave.Wilkes-Barre, Pa.

ALAN PHILLIPSP.O. Box 1026London, Ontario, Canada

THQMAS W. TAMS2 Ewington Ave.Trenton 8, New Jersey

DANIEL L. TREACY1025 E. Maple RoadBirmingham, Michigan

JUNIORANTONIO ZWNI~A AYALA

Rebsamen No 512Mexico 12, D.F. Mexico

KENT JOHNSON8501 5. Loomis Blvd.Chicago 20, Illinois

HERBERT J. S~T(*~KINGER6~7-B North KenwoodGlendale 6, €alif.

AFFILIATEPETER ~. DAUGERT

221 Conyngham Ave— Wilkes~Barre,,Pa..W. C. HAMILTON

P.O. Box 41Sheffield, England

WALTER H. LARSON221 Conyngham Ave.Wilkes-Barre, Pa.

JAMES S. PRASCH1360 Indianwood DriveBrookfield, Wisconsin

AANEN THORSLAND521 27th St. (Apt. 5)Sacramento 16, Calif.

STUDENTBALDEVBHAI SHANKEDBHAI PATE

215 N. IngallsAnn Arbor, Michigan

CHESTER L. SPRAGUE372 Marlborough St.Boston 15, Mass.

Additional Proceedings Papers—6th Annual Convention, will bepublished in the March PCIJOURNAL.

PRESTRESS ‘ CO C ETE ~NSTITUT

205 W. Wack r DriveC icago 6, II.

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