Tall Building Form Generation by Parametric Design Process

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CTBUH 2004 Seoul Conference 1

Tall Building Form Generation by Parametric Design Process

Sang Min Park, Mahjoub Elnimeiri, David C. Sharpe, Robert J. Krawczyk

1 Ph.D. Candidate, College of Architecture, Illinois Institute of Technology2Professor, College of Architecture, Illinois Institute of Technology

3Associate Professor, College of Architecture, Illinois Institute of Technology4Assistance Professor, College of Architecture, Illinois Institute of Technology

Abstract

Historically, the development of the tall building has been dependent on technological advancements. Asthe continuous advancements of technology impacted tall building design and planning, the architectural profession also changed to keep up with the rapid technological progress. One of the recent remarkabletechnologies is the use of the computer to analyze complex structural systems and its ability to produceconstruction documents. However, digital tools to assist in architectural design to generate innovative tallbuilding forms have not progressed at a comparable rate. This paper will discuss the generative concepts of a

tall building forms and an innovative design process using digital tools that are based on a parametric designapproach. The paper will discuss a series of transformations based on architectural as well as geometrical properties that can be used to define tall building forms and the development of a process to generaterepresentations needed for visualization and study model making. The intention of the paper is to inspirecontinued interest in new concepts of tall building forms and to investigate a design process that integratesarchitecture with digital methods.

Keywords: Tall building form, Design process, Digital tool

Introduction

The symbolic value of a tall building is verypowerful in a urban landscape. To architects and thepublic, the form of a tall building is primary concern,

and the attitude is critical toward the outcome of thedesign. The approach to designing evolutionary tall buildings is an open subject of professional debate,and the role of the architect in designing them is veryimportant, particularly from the point of view of formgeneration. Recently, a few architects have presentedbuilding forms that exhibit a more complex geometry.With the introduction of digital tools, generativedesign possibilities can be more fully explored withthese geometries.

In the development of tall buildings, the overall building form should be one of the major elementsthat impacts building aesthetics and behavior.However, architecturally, structurally and aesthetically,

it is a complex task to develop an optimal form for tallbuildings due to the interrelations of large numbers ofcomponents. The attempt to combine more than one

major function in a building or complex presents thedesigner with several problems. Each function hasdifferent planning considerations for optimum andhabitable space. Due to the inter-related functional

requirements within a building, one change can affectmany other factors that must be considered whendeveloping a project.

The use of digital tools in the schematic designphase of tall building design is still quite limited. Thecomputer-aided design includes using a computer notonly for visualization, analysis, and evaluation, butalso for the generation of designs or, more accurately,for the rapid generation of computable designrepresentations describing conceptual designalternatives. Potential design alternatives aregenerated and evaluated in order to obtain the mostpromising solution.

The advantage of parametric design in this research

is to plan and synthesize the overall requirements andrelationships of many design elements into one form(see Figure 1). This process allows the designer toinvestigate variety of possible solutions quickly.

This research is concerned with tall building formsgenerated by digital tools based on the architecturaland structural criteria. It explores potential generativeforms, and also suggests an innovative design processusing digital methods. The following objectives havebeen identified for this:

Contact Author: Sang Min Park, Ph.D. Candidate

College of Architecture

Illinois Institute of Technology

3360 S. State

Chicago, IL 60616 USA

Tel: 312-567-3264

e-mail: [email protected]


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Define the relationships between design criteria andoverall tall building form

Explore the various geometries and transformationsfor tall building formSuggest an innovative digitally based design processfor tall building designSuggest generative forms and concepts of tall

building that meet the design criteriaDevelop an architectural design methodology usingdigital tools

Fig.1. Design Elements of Tall Building Form

Proposed Design Process

The design of a tall building involves professionalsfrom several disciplines, starting from the conceptualdesign to final design documents. The entire process israther complex in that it requires experts fromdifferent disciplines. In the schematic design phase,architects and engineers create a set of alternative

possible tall building forms. The output of conceptualdesign can lead to design concepts that can be used asa basis for embodiment and detail design. Althoughschematic design phase only occupies fifteen percentof the total design fee, this stage is more importantthan the other stages because about eighty percent ofthe resources required to build a structure arecommitted by decisions made during the conceptualdesign stage. This early phase of design is the mostcrucial part of the entire process.

Potential design alternatives are generated andevaluated in order to obtain the most promisingsolution. Ordinarily, several alternative solutions are proposed to the client for consideration or approval.However, the selection is complex to arrive at the bestalternatives since tall building forms include a largenumber of disciplines that sometimes conflict withdesign requirements. Once the proposed scheme hasbeen accepted the building design is progresses intothe design development stage.

Fig.2. Proposed Design Process and Tools

In parametric design, it is the elements of aparticular design that are declared, not its shape. Byassigning different values to the parameters, differentconfigurations can be created. The proposed designprocess in this paper is based on parametric input (seeFigure 2). Parametric design consists of a set ofvariables and a series of relations to define a form.The overall form can be manipulated by alteringspecific parameters that are able to automaticallyadjust building data such as total gross area, total building height, total number of floors, and aspectratio.

Fig.3. Design Parameters

Parameters are expressed as numeric andgeometrical relationships. To design with thesesrelationships requires the establishment of a series of parametric principles. Development of tall buildingscould be determined by design factors; these factorshave several parameters such as user needs, functionalrequirements and structural demands (see Figure 3).


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These design parameters are dependent upon planningconsiderations. Items related to planningconsiderations are building functions, core planning,lease spans, and floor-to-floor height. Theseconsiderations are interdependent with each other andthey affect the overall building design. In this research,all of these considerations are the design parameters to

achieve an appropriate solution.Before selecting a building geometry, it is necessary

to set the appropriate spatial requirements. These areasmust include base and top floor areas and appropriatecore areas with proper lease span by function. Thecore area is determined by total number of elevatorsand elevator zoning. The number of elevators can becalculated by given gross area of each function anddesign guidelines. The base and top floor areacalculation worksheet consists of these complexrelationships (see Figure 4). By using the worksheet,appropriate core area, proper base and top area, andnumber of floors each function will be set quickly before form generation. This process establishes the

architectural requirements for the project.

Geometry and Transformation

Geometry plays a critical roll in the generation of building form and structure. Geometry in theschematic design helps to explore design ideas. Thispaper explores potential geometries and new conceptsof vertical transformation to create an overall spatial

form using non-conventional concepts. A geometricshape has own architectural and structuralcharacteristics. Tall building forms can be designedbased on geometric shape. The explored geometries inthis paper are focused on symmetry. One polygonscorner can be another polygons center. Thesecombinations generate many symmetrical forms

usable for tall building form as shown in the geometrytable (see Figure 5). Same side distances and same bay corner columns characterize these symmetrygeometries.

Conventional building form along its height can bedescribed as prismatic, tapered, and setback. This paper presents non-conventional verticaltransformations such as setback, section morph, twist,and curvilinear. This investigation covers thedevelopment of a series of starting and ending floor plate shapes for a set of floors. Figure 6 shows thecombinations of starting and ending geometries.According to each combination, different number ofcontrol point will be decided to create a form.

Throughout this process, numerous new concepts oftall building form can be explored. Digital proceduresare developed to transform starting floor plate shapeto the ending shape. Operations such as rotation,scaling, and morphing are demonstrated for a varietyof basic shapes. Embedded in the generative processare architectural and structural criteria that limit theresulting form.

Fig 4. Base and Top Area Calculation Worksheet


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Fig.5. Examples of Explored Symmetry Geometries

Fig.6. Examples of Combinations of Base and Top Geometries


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Form Generation

In the conceptual design phase, creativity andexploration are very important. With appropriate inputparameters, the form generation program is executed.In this process, forms can be generated with anycombinations of the explored geometry and thedefined vertical transformation (see Figure 7). The

form generation program consists of four groups,which are section morph, setback, twist, andcurvilinear group. Each group has differentarchitectural and structural characteristics anddifferent parameters to create a form.

Fig.7. Exploration of Generative Forms

Figure 8 shows four example forms with differentvertical transformations of same combinations of baseand top geometries. After the combination of base andtop geometries from the geometry table is selected,each geometrys area and dimension are set based onthe area calculation worksheet. Examples weregenerated with 2,000,000 sq ft office, 400 units hotel,

and 400 units apartments. The area calculationworksheet shows approximately 400,000 sq ft for baseand 12,100 sq ft for top. Figure 9 shows the selectedgeometries and dimensions.

Fig.9. Example of Selected Base and Top Geometries

Fig.8. Examples of Generated Forms


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After base and top geometries are set. The formgeneration program can be operated with several parameter inputs to get total number of floors andforms. Automatically, each forms building data andstructural layout data that are members and joins readfor any of structural analysis program are created.The Parameters of each group:

Section Morph: The number of control point dependson the combination of geometry. Parameters; base andtop geometries, location and number of control points,number of floors by function, and floor-to-floor heightby function.Setback: The number of setback will be determined by architectural and structural design criteria.Parameters; base and top geometries, location andnumber of control points, floor-to-floor height byfunction, number of setbacks, rate of each setback,and number of floors of each step.Twist: The angle of twist will be determined byarchitectural and structural design criteria. Parameters;base geometry, location and number of control points,

floor-to-floor height by function, and angle of twist.Curvilinear: The line factor of curvilinear line will bedetermined by architectural and structural designcriteria. Parameters; base and top geometries, locationand number of control points, number of floors byfunction, floor-to-floor height by function, line factorsof each line, and curve factors of each Line.

Evaluations

In this phase, explored potential tall building formscan be evaluated in more detail against architecturaland structural design criteria. The three-dimensionalmodel is one of the manifestations of the computermodel. The forms are developed completely withdigital models from the very beginning. As an

outcome of this research, three-dimensional generated building forms can be constructed asthree-dimensional surfaces for rendering andthree-dimensional model for structural analysis (seeFigure 10). To check architectural building propertiesautomatically a spreadsheet can be generated in theMicrosoft Excel format (see Figure 11), and input datafile can be created for direct analysis by structuralanalysis program.

Finally, to physically compare alternative forms,study models can be made by the laser cut process.With given scale of model, the material and itsthickness for laser cutting will be decided. The lasercut program generates every floors plate

configurations and register slots at a given scale (seeFigure 12). Once every floor plate is cut with a lasercutter, they are assembled with the register slot. Asshown in the Figure 15, the study models in this paperare made at 1 to 600 scale. Additionally, more-detailedmodel can be made showing columns, floor slabs,core shape, and envelop

Fig.10. Examples of 3D Models

Fig.11. Example of Building Data Spreadsheet


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Fig.12. Example of All Floor Plate Generated by Laser CutProgram

Evaluations with the Outcomes:3D Surface Model: Renderings, evaluate overallbuilding aesthetics3D Members and Joints Model: Prepare structuralinput data for structural analysis programSpreadsheet: Overall building data, evaluate detailedarchitectural issues such as locations and specificfloor-to-floor height for mechanical floors, sky lobbies,and commercial retail floors

Study Model by Laser Cut: Mass model, evaluateharmony and relationship on the given site with

physical modelFloor Plate of Every Floor: Prepare for each floorplan

In the schematic design phase, parametric designcan generate a series of designs quickly, whichconsider a series of architectural and structural designcriteria. The proposed design process has theadvantage that procedures perform set of inter-relatedall necessary tasks in the schematic design phase suchas planning and design, visualization, analysis, andmodel making (see Figure 13).

Fig.13. The Performance of The proposed Design Process

Conclusions

The intention of this research is to inspire moreinterest in a innovative concept of tall building formsthrough integration of architecture and digitaltechnology. The focus of this research is to suggestthe generative forms as applicable to architecture bymeans of architectural and structural evaluations and

also form generation process. This research willcontribute to the Form Development of Tall Buildings.

Technology can be used as an architectural tool to produce not only the better performance design butalso generative and innovative concepts. Theimprovement of design quality and design processusing advance technology is more practical andchallenging task for the professional development. Byintegrating digital tools based on design criteria ruleand design requirements with new concept tall building form, the generative potential forms can bedetermined. Development of such a method enablesthe designer to uniquely apply their design conceptseasily and evaluate a variety of alternatives.

References1) Council on Tall Buildings and Urban Habitat, (1995) Architecture

of tall buildings. New York: McGraw-Hill Inc

2) Hyeong-ill Kim, (2004) Space efficiency in mixed-use high-rise

building. Illinois Institute of Technology

3) Kamon Jirapong, (2002) Discoveringarchitecture within seashell.Illinois Institute of Technology

4) Nianquan Zhang, (2001) A computer-based environment for

preliminary structural design, design collaboration and design

automation of tall buildings. Hong Kong University

5) Youngsun Choi, (2000) A study on planning and development of

tall building. Illinois Institute of Technology

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Tall Building Form Generation by Parametric Design Process