Steel Connections: Fun is Fondling the Details1Steel Connections: Fun is Fondling the DetailsTerri Meyer Boake, University of WaterlooVincent Hui, Ryerson UniversityThe Problem:The last 40 years have seen a remarkablechange in the nature of the design of steelframed buildings. Steel framing prior to theonset of the High Tech movement in the1970s, which can be characterized bybuildings such as Foster’s Sainsbury Centerfor the Arts and Piano and Rogers’Pompidou Center, depended on simplegeometries and predominantly standarddetailing – detailing that closely mimickedthe sort that is outlined by the AmericanInstitute of Steel Construction in theirdetailing handbook. From the perspective ofthe type of steel design that is seen incontemporary architecture, styles havechanged significantly. Complex geometries,diagrids and curves have become the norm.Connections have since becomeincreasingly complex and bear little directresemblance to standard framed methods.Where students seem willing to attempt toincorporate these highly articulated steelframing methods into their architecturaldiscourse, they often fall short of carryingthrough their detailed design to includehighly developed, articulated details thatengage the realm of constructability. Thedrawings and renderings that are producedappear to make widespread use ofseemingly “welded” connections that usenondescript looking steel members as thisseems to be the easiest way to avoidcoming to grips with the reality of the detail.The drawing or rendering scale is often keptquite small, as also to avoid having to adddefinition to either materiality or line work.This might be called “connectionavoidance”.If one of the most difficult issues thatstudents face when they are preparing todesign a steel building is the detailing of theconnections, we maintain that the majorroadblock to engaging architectural studentsin steel connection design (and steel designin general) rests in the way that it isnormally taught. If referencing the pureengineering-driven “steel design” courses,this lies in an education formed of elementalcalculations and disparate "bits" that aretaught with little reference to either actual orinnovative buildings. Students learn aboutconnections from the point of view of loadtransfer and bolting requirements, but arenever taken to the more advanced step ofunderstanding how that simple connectioncan become something more complex andinteresting, as well as the role it plays in theoverall context of the design of a building. Ifconsidering the steel content in materialsand methods based courses, anexamination of the majority of texts wouldconfirm reference to fairly typical “basecase” architecture, and very traditional,simple framing methods. The diagrams inthese texts outline the typical means toconnect members, and normally includephotographs of relatively generic lookingsteel framed buildings. This is an essentialstarting point when learning steel design,but does not elevate learning to a uniquely“architectural” level.The Proposal:In preparing our own students to undertakethe annual Steel Structures EducationFoundation Student Design Competition,through our parallel Building Construction(Boake) and Digital Design (Hui) courses,we began to create synergies and exercises
2BTES Conference: Assembling ArchitectureAugust 2009 Proceedingsin a degree of cross-fertilization. It wasrecognized that these 3D details actuallyprovided more information than the sets ofstatic photographs from which they werederived as the digital files could betransformed into interactive VRML “movie”files, which would allow for the rotation andmanipulation of the details (including zoomfunctions). In fact, the resultant movie filesallowed the user to “fondle” the details.Figure 1. Samples of some of the digitally rendered steelconnections from the first year students, completed fortheir digital communication coursethat created a new way of looking at steeldetails. An exercise was given in the DigitalDesign class where students were asked towork in groups, examine the steel details ofsome steel framed buildings that had moreinnovative connections (introduced in theBuilding Construction class), and renderconnection “families” in FormZ. The ideaunderlying the exercise was for the studentsto work in small groups to create and share3D aspects of the details in order tounderstand how a degree of uniformitycould be created in the aesthetics of thejoints that was in part derived from the waythat they were put together in terms of steeldetailing (Figure 1). The lecture on steeldesign in the materials and methods classwas given parallel to the exercise, resultingThe idea behind the nature of the resourcewas derived from this exercise. The ideabehind our proposal to the Steel StructuresEducation Foundation of Canada was quitesimple: use a multi media interface todemonstrate to students how to go from the"standard" connection to the "elaboratedetail". In doing so, we would create aresource that would be captivating enoughto get students more interested in designingsteel structures by showing them how someof the complex details of more renownedbuildings were derived from the language ofbasic steel connections. Most existingresources and texts illustrate the basicmethods used to create steel connections(shear, moment, tension, welded and boltedjoints), but never provide students with anexplicit means to help them understand theway they can leverage the “basics” to createsomething more elaborate. This project willhelp the students both work from the basicsforward, and from the complex case studiesin reverse, to see how simple themanipulation of the ordinary to theextraordinary might be. The resource isbased on the initial photographic case studywork presented in the website “Steel: Fun isin the Details1”, that has documented agallery of intriguing steel structures thatlargely use AESS or innovative structuralsteel as a key feature of their designs.The engagement resultant from being ableto manipulate or fondle the details gave riseto the core idea of the proposed resource,that of using a series of details drawn fromthe online gallery, to create a series ofinteractive “details” that show the
Steel Connections: Fun is Fondling the Details3Figure 2. A detail from Polshek Partnership’s Rose Center (original photo in top right) explored in different mannersthrough an interactive 3D PDF modeltransformation of the more complex detailsfrom the basic connection types from whichtheir essence has been drawn. The initialthought was to create MOV or VRML files,to allow for rotation and zoom functions.These interfaces proved too “bulky” to beput directly into an online web interface.Despite the ability to navigate around thesedetails, the models remained static andfailed to provide a robust framework forstudents to understand assembly anddetailing. Experimentation led to theadoption of an interactive PDF file format asit is much smaller, ubiquitous, and alsoprovides the user with the ability tomanipulate the view as well as look atsimple orthographic drawings of the samedetail. Rather than encumber audienceswith inaccessible complexities ofconventional CAD applications, theinteractive PDF empowers the viewer with agreat deal of flexibility in examining steeldetails as an assemblage of componentswithin a structural system. Through amatter of clicks, users may navigateassemblies from any perspective, removeelements to understand componentsystems, and even create virtualizedsections in order to fully understand thedesign intent and the detailing rendering itfeasible (Figure 2).SignificanceStudy:oftheMiniCaseAlthough the proposal is intended to focuson the connections, we felt it important toframe the connections within the context ofthe smaller case study. Putting thereferenced complex connections used in theexamples in the resource in the context ofthe building and its construction process isalso critical to gaining a properunderstanding of the choices that weremade in designing the detail or connection.The following example illustrates simplejointing and a basic W to column connectionfrom Frank Ching’s “Building ConstructionIllustrated”. The images beside are for theframing of the steel substructure for Foster’sLeslie Dan School of Pharmacy and thelifting of the fragment of the pod into place(Figure 3). Where the tube to tube weldedconnections in the Foster work might begeometrically logical, the splices, theirlocation and frequency can be explained byunderstanding the construction andassembly requirements. The simple fact that
4BTES Conference: Assembling Architecturethe steel is ultimately clad, relieved thedesign of the responsibilities of AESSAugust 2009 Proceedingsrelational groupings, the resource willempower students with what WeinbergerFigure 3. (clockwise from top left): Classic connection, detail from F. Ching ofa type of tube to W connection, detail oftube to tube connection with plate on the Leslie Dan School of Pharmacy, crane lifting pod segment for placement, andfinished building – pods clad in gypsum board with painted finishfinishes, but also meant that it had to be“sleek” enough to permit the ease of finishapplication.Our examples propose to take studentsfrom basic details to those that use morecomplex geometries, varying steel shapesand hollow sections, as reflected in a rangeof intriguing built examples. We will takeapproximately 20 different innovative steelframed buildings and break them apart intokey connection details, developed in termsof their connection types, and to varyinglevels of detail as required.Navigation of the Content:The content of the resource will make use ofthe web interface to allow for navigation tobe carried out in various ways. Given thecurrent shift from categorized order towardrefers to as metadata classification – thattopics may be sorted based on a multiplicityof taxonomies.2 It is felt that students wouldengage the content to a) figure out how tounderstand basic connections methods; b)investigation a certain type or style ofconnection (hinge, tension, moment) and c)see the range of connections that havebeen used within a particular case studybuilding. The “basic connection methods”will be illustrated in very generic terms andbe annotated to demonstrate the stress andfailure typologies associated with theconnections (tension and compressionforces, shear planes, bolt shearing andplate pull through, for example). Theconnections that have been derived fromthe 20 case studies will be subdivided intoAESS versus structural steel buildings, aswell as the details within each case studyinto their specific connection type (framed,
Steel Connections: Fun is Fondling the Detailsmoment, tension, cast). The ability to makehot links in a web based interface will allowthe user to jump from the case study to theconnections, or from the connection to the5steel building, so this section will briefly walkthem through these issues and reflect onhow this impacts the decisions we makeregarding designing connections, of how weFigure 4. The flow chart of the navigation of the resourcemore general information of the case study,and back to the explanation of the basicprinciples, and vice versa. From within each“basic connection method” outlined, therewill be linkages provided to the elaborateddetails from within the case studies wherethis connection method is employed (Figure4).Basic Connections and Methods:Within this category we will begin with abrief overview background to steelconstruction. This is intended to becomplementary to the Materials andMethods or Steel Construction text, so willnot focus highly technical backgroundmaterial related to steel manufacturing orspecifications. Within this section we willexamine basic jointing, framing types, andthe rationale behind the choice of bolts andwelds. Bolting and welding issues will beshown to include fabrication,constructability, transportation, and erectionissues. Most students are not familiar withthe logistics of the physical construction of aconnect steel -- bolting and weldingbackground -- lap joints, butt joints, etc.We will begin with a matrix of standardconnection details, modeled upon the AISCConnection Types. They will be brokendown into framing types (beam to column,column to column, truss, tension, momentresisting, etc.) These will be redrawn inorthographic (plan, section elevation) aswell as 3D axonometric views. Theemphasis will be towards understanding thehow and why, so sizes will be purposefullyomitted throughout the resource. This couldalso be considered a liability issue lestsomeone try to copy these.A discussion of issues in the design ofAESS - as reflected in an upcomingCanadian CISC Guide will be included inthis section. The elaboration of AESSrequirements is extremely important as itframes many of the subsequent choices thatmust be made in detailing andunderstanding the physical and financialimplications of the connections.
6BTES Conference: Assembling ArchitectureAESS: Not allCreated Equal SteelneedbeArchitecturally Exposed Structural Steel(AESS) has grown in its use and brings withit a range of considerations that are quitedifferent from those associated with regularstructural steel design. Terri Boake hasbeen working with the Canadian Institute ofSteel Construction Task Group to write anew specification and Guide to assistarchitects interested in design with AESS.3This resource goes well beyond the AISCGuide that was published as an issue ofModern Steel Construction in 2003.4 Thefindings of this5 Task Force and keyinformation from the Guide will be integratedinto the project. Although students seldomare required to carry out detailed costing oftheir projects, there are some significantcost implications connected to AESS designthat related to the level of finish and otheraspects of the fabrication of the joints. Themultimedia resource will be used to highlightthis part of the design process associatedwith AESS connections.Architecturally exposed structural steelspecifications place a higher level ofrequirements on ironwork that lie above andbeyond the regular structural and safetyaspects of steel construction, in theiradditional address of aesthetic and designconsiderations. Not only must more care betaken during the shop and field fabricationof AESS product, but other operations,beyond those of normal fabrication, arenecessary to raise the aesthetic andtectonic level of the steel for purely visualand tactile goals. The steel must be seen tobe smooth and defect free. It may also berequired to be touched and felt to be smoothand defect free if situated at the public level.If bolted connections are used, this may notbe a difficult requirement as the tectoniccharacteristics of bolted connections areperceived to be somewhat “busier”, and thestructural steel or tube itself is unlikely torequire more than proper paint finishing.However, when welded connections areAugust 2009 Proceedingsspecified, extra expense is usually incurredby the addition of grinding operations. Thishas much to do with the perception ofwelded connections as being smooth andphysically seamless. Welds, particularly ifdone by an unskilled worker, can be seen tomar the fluid appearance of the finalproduct. Specialty elements that requiresteel to be cast into unusual shapes, or bentinto complex curves, also places additionalrequirements on the fabrication andinstallation that will increase the cost of thesteel well beyond the norm.Such information needs to be conveyed toarchitects (and architectural students) sothat they understand the impact of “lineitems” in specifications. Grinding and filingoperations are time consuming, hencecostly, and can be quite unnecessary if thesteel in question is not in a position for closescrutiny, via sight or touch.Sorting by Case Study:In order for students to appreciate therelevance of any detail or connection type,they need to both see and understand it inthe context of the building. For them topotentially become engaged, the building or“mini case study” needs to be of a buildingthat has the potential of capturing theirattention. The projects that will be used asthe basis for the resource will include worksby Frank Gehry, Norman Foster, RichardRogers, Daniel Libeskind, Will Alsop, RemKoolhaas, Santiago Calatrava and thePolshek Partnership, amongst others.These types of buildings are not typicallypart of the normal Materials and Methodstexts, so should help to draw the studentsinto the resource. The projects will bedivided between those that useArchitecturally Exposed Structural Steel andthose that use innovative structures that arenot exposed. The projects will include arange of connection types and membershapes, so that their various connectionscan feed into the portion of the resource thatexamines the connection types in greatdetail. A variety of finishes will be
Steel Connections: Fun is Fondling the Detailsrepresented so that issues of paint finish(impact of degree of gloss), intumescentcoatings and galvanizing can be addressed.A simplified case study will be developed ofeach of the buildings. These will primarily bephotographically based, and also includesome 3D interpretive diagrams of the waythat the structure of the building “works”.This will be in keeping with a basicexplanation of the structure of the building,but will not go into great detail as thepurpose of the resource is not to createdetailed case studies, but more to use thebuildings as a vehicle that can generateinnovative steel connections that can bedissected and used as a tool for learning.The base case study will be broken apartinto connection details that are viewed asphotographs. The photographic detail fromthe real building will then be will be modeledin FormZ and orthographic blackline, andannotated with explanations to describe theroles and functions of the connection detail,jointing systems, and how it is part of alarger language of connectivity in the overallbuilding. The write-up will speak to some ofthe other choices that have been made inthe design of the detail in terms ofconstructability, modularity, fabrication,costs, replication, workmanship anderection. The interactive PDF files gobeyond allowing users to simply “spinaround” the details. That users canmanipulate the detail by turning on and offspecific components to reveal assembly,arbitrarily cut sections to understandconstruction details, and takemeasurements from these models are but afew technically robust qualities that themedium has to offer. As design educators,it is important to emphasize the designvalue of this medium as it also allowsaudiences to engage a multiplicity ofconsiderations ranging from viewing thedetail from macro and micro levels,removing components to alter its visualappearance, to even witnessing the impactof a detail in different lighting conditions(Figure 5). The synergy of these elements7create an engaging and comprehensivepackage for students.Sorting by Connection Type:We would imagine at this point that the setwould include around 20 fully developeddetails, as well as a range of lesserdeveloped or simpler details. The finalnumber will depend upon how many uniquebase details can be isolated from AISC andAllen, and how many interesting finisheddetails we identify in the case study projects(including time/resource limitationsassociated with the project). There aresimilarities in the details that will allowgrouping various projects in order to usesome of the basic ideas and show how theymay lead to variations. This will showstudents how a standard detail can beturned into a number of different solutionsFigure 5. 3D PDF files allow for interactions that betterinform design ranging from arbitrary and real-time sectiongeneration (top) and even lighting conditions (bottom)that start off with the same principles.
8BTES Conference: Assembling ArchitectureThe connections that have been developedas part of the mini case studies will besorted by