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FORUM

Integrated Design and Construction of Tall Buildings

Abbas Aminmansour, A.M.ASCEStructures Program, School of Architecture, Univ. of Illinois at Urbana-

Champaign, Champaign, IL 61820-6921. E-mail: [email protected]

Kyoung Sun MoonSchool of Architecture, Yale Univ., New Haven, CT 06511.

Contemporary tall buildings frequently incorporate distinctive ar-

chitectural designs that require unique and innovative design of

structural, mechanical, lighting, electrical, and other building sys-

tems. In addition, the massive scale of tall building systems cre-

ates critical interrelationships and dependencies among these

systems. Construction of tall buildings is impacted by the build-

ing architecture and systems and may require special construction

materials, equipment, techniques, or processes that necessitate

close collaboration between the contractor and the design team.Moreover, issues such as efficiency and economy of operation

and maintenance of tall buildings during their life-spans offer

incentives for the design and construction team to think critically

beyond the construction phase and incorporate features and ma-

terials that increase the return on the developers investment. Fur-

ther, the increased sensitivity to the environment and our limited

natural resources influence not only the design, but construction

material and techniques used in the development of tall buildings.

Thus, design and construction of tall buildings is a multidisci-

plinary challenge bringing together the architect, architectural

engineering consultants including the structural engineer, me-

chanical engineer, and lighting engineer , and the contractor from

the conception and planning of the project to completion of con-

struction of the building. This collaboration requires general

knowledge and understanding of the different disciplines by each

professional involved in the process.

This paper presents a number of strategies for the successful

execution of tall buildings. Teamwork and integrated design and

construction for comprehensive and efficient outcomes are par-

ticularly highlighted with emphasis on the role of the different

parties involved in the planning through to the operation of tall

buildings.

Structural Systems, Spatial Configurations,and Building Aesthetics

The invention of iron/steel skeletal structural systems in

Chicagothe technological driving force of tall building

developmentsled to the emergence of modern tall buildings.

Since then, tall building structures have evolved toward taller and

more efficient systems in conjunction with changing functional

requirements based on the development of new management sys-

tems Abalos and Herreros 2003; Russell 2003 . Departing fromthe conventional frame structures, a significant evolution occurred

with the development of tubular structures in the late 1960s,

which satisfied both structural and functional requirements.

Tube systems have provided very efficient structures with

column-free office environments, providing greater flexibility in

building use. With their major lateral load-resisting systems lo-

cated at the building perimeter, tube structures by their naturehave great potential of being a major element of building aes-

thetic. This potential has been either strongly pursued or inten-

tionally minimized depending on specific design situations.

Among various tube configurations, framed tubes such as the

ones used in the demolished World Trade Center Towers in New

York and in the Aon Center in Chicago Fig. 1 are rarely used

today due to their very closely spaced columns, which obstruct

the great views typically provided by tall buildings. Braced tubes

and their variations are still used in contemporary tall buildings

such as the World Financial Center in Shanghai Fig. 2 . How-ever, unlike the clear expression of structure in Chicagos John

Hancock Center Fig. 3 , the perimeter braces in the World Finan-

cial Center are hidden behind a reflective glass facade.

One of the most prevalently used tube systems today is the

diagrid. With its new aesthetic expressions and great structural

efficiency for tall buildings in resisting lateral forces, diagrids

have been used for major tall buildings such as the Hearst Tower

in New York Fig. 4 , the Swiss Re Building in London Fig. 5 ,

the Lotte Super Tower in Seoul, and the Guangzhou Twin Towers

in Guangzhou. In these buildings, diagonals are strongly ex-

Fig. 1. Aon Center in Chicago Courtesy of Abbas Aminmansour

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pressed on the building facade as primary aesthetic componentsas well as building identifiers. While most diagrid structures are

designed with diagonals placed at uniform angles, some diagrid

structures, such as the Lotte Super Tower, employ varying-angle

diagrids, with steeper angles toward the ground. This varying

angle configuration of diagrids provides superior structural per-

formance and more dynamic visual expression for a very tall

building Moon 2008 . Diagrids are also used as structural solu-tions in irregular freeform shape tall buildings such as the Phare

Tower in La Defense and the Fiera Milano Tower in Milan, which

lead another direction of contemporary tall building design.

Compared with conventional orthogonal structures, diagrid

structures require more complicated joints where at least six

structural members meet. Thus, careful consideration should be

given to design and construction of diagrid joints for successfulproject execution. Prefabrication of the complicated diagrid nodes

combined with the fact that these joints can be designed with pin

connections due to the triangulated configuration of diagrids may

lead to less work at the job site. Due to the absence of vertical

structural members, geometric configuration of faade systems

should be well coordinated between architects and engineers to

achieve desired aesthetic and functional performance.

Another tall building structural system used worldwide today

is the core-supported outrigger system. By connecting shear core

and exterior columns or mega columns, the system maximizes its

bending rigidity with an extended moment arm. While tube struc-

tures concentrate lateral load-resisting system components, which

resist both shear and bending at the buildings perimeter, typical

core-supported outrigger systems resist shear primarily through

their cores and bending through the cores and exterior columns

connected to the cores by the outriggers Moon et al. 2007 . In

resisting lateral forces, outrigger systems perform with the

couples created by tension and compression in the perimeter col-umns connected to the outriggers. However, careful structural

planning may eliminate the actual tension with gravity loads

Smith and Coull 1991 .For very tall buildings with multiple outriggers of usually

double-story heights, coordination of the structural system with

spatial organization and building aesthetics is crucial in successful

design. As is the case with the Jin Mao Building in Shanghai Fig.

6 , outriggers or other deep structural components may be located

at the mechanical floors, which are vertically distributed along the

building height and also typically require double-story heights.

Fig. 7 shows the mechanical floor of a tall building with signifi-

cant structural components present on that floor.

Structural efficiency and vertical building proportioning re-

lated to aesthetics and function as well as efficient zoning ofmechanical systems should be considered simultaneously in de-

termining the locations of outriggers. Unlike tube structures, out-

rigger systems do not rely entirely on building perimeter

structures in resisting lateral forces, thereby allowing the exterior

columns to be more widely spaced. Consequently faade design is

less constrained by perimeter structures Ali and Moon 2007 .

Building Form and Structural Performance

Todays architecture, including tall buildings, can be understood

only through recognition of the dominance of cultural pluralism.

Fig. 2. Shanghai World Financial Center Courtesy of Abbas Amin-

mansour

Fig. 3. John Hancock Center in Chicago Courtesy of Abbas Amin-

mansour

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Early design of tall buildings culminated with the emergence of

the International style, which prevailed for decades. Today, how-

ever, as is true of other building types, multiple design directions

are prevalent for tall buildings. The lack of a dominant style has

produced various building forms, such as free forms, twisted

forms, tapered forms, and tilted forms, and the supporting struc-tural systems. The importance of an integrative design and con-

struction approach is more significant today due to the complexity

of building forms compared to the Miesian building forms pro-

duced during the mid-twentieth century.

Early irregular freeform tall buildings were proposed by some

architects such as Frank Gehry and Peter Eisenman in the late

twentieth century, but their designs never left the drawing boards.

Today, however, many freeform tall buildings, such as Daniel

Libeskinds Fiera Tower, Zaha Hadids Dancing Tower, and Thom

Maines Phare Tower, are designed and planned to be actually

built. Irregular freeform design has become a new direction in

contemporary architectural design. Another interesting approach

in tall building design today is the twisted forms found in the

Turning Torso in Malmo Fig. 8 and the Chicago Spire in Chi-cago, both designed by Santiago Calatrava. In conjunction with

either the new building forms or the conventional building forms,

tapered or tilted forms are also prevalent in todays tall buildings.

From the viewpoint of building forms, these approaches can be

understood as reactions to once globally prevalent prismatic

building forms. This type of cyclic transition in building forms

related to architectural aesthetics can be traced throughout the

history of architecture Moon 2005 .

From the viewpoint of corresponding structural systems and

performance, todays irregular building forms require more com-

plicated system design, analysis, and construction. But, on the

other hand, they may offer better performance in response to dy-

namic wind forces. Unlike conventional rectangular box building

forms, any irregularity in building form helps prevent wind from

forming organized vortexes which in many cases produce themost serious vibration problems in the across wind direction.

There exists a great potential in design integration to produce

better performing buildings. As an example, the World Trade

Center towers required viscoelastic dampers to be installed for

motion control after occupancy, while the Burj Dubai Fig. 9 , amuch taller building, is designed without any damping mecha-

nisms. With many irregular setbacks in the Burj Dubai, winds are

expected to be confused without forming organized vortexes

Baker et al. 2008 . The coordination of irregularity in buildingforms between architects and engineers to satisfy building aes-

thetics and at the same time to maximize structural performance

will lead to a higher-quality built environment.

Some typical features used by architects and structural design-

ers to reduce tall buildings responses to wind forces include ver-tically tapering profiles, reduced wind sail at top of the building,

rounded or chamfered corners, and notches or vents Nordenson

and Riley 2003 . Today, wind tunnel analysis is an integral part of

design of tall buildings. Such experimentations offer the designers

valuable insight into the building response to wind. Information

obtained from wind tunnel tests are based on the building shape

as well as any obstacles, such as other buildings, that may influ-

ence airflow and formation of vortices around the building.

To further reduce vortex-shedding-induced dynamic motion of

tall buildings, various damping systems can be installed integrally

with other building systems. For the structural design of a very

Fig. 4. Hearst Tower in New York Courtesy of Abbas Aminman-

sour

Fig. 5. Swiss Re Building in London Courtesy of Kyoung Sun

Moon


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tall building, it is possible for the serviceability requirements to

be dominant Connor 2003 . In early days, even structural bracing

members were always hidden from building faades because ex-

posure of these structural elements was opposed to the architects

aesthetic direction. It took a long time for these once purely struc-

tural elements to be exposed in building faades, as can be seen inChicagos John Hancock Center of 1969 and todays diagrid

structures. Damping devices, like bracing members, have often

been kept out of the view in tall buildings as well. However, the

pendulum-type mass damper in Taipei 101 is exposed for viewing

in the atrium of the building as an ornamental element Fig. 10 .

There is a great potential to integrate these performance-driven

technologies with building aesthetics.

Constructability is a serious issue for the successful execution

of irregular forms. As building forms become more irregular, pro-

Fig. 6. Jin Mao Building in Shanghai Courtesy of Abbas Aminman-

sour

Fig. 7. Two-story mechanical floor of a tall building with significant

structure present Courtesy of Abbas Aminmansour

Fig. 8. Turning Torso in Malmo Courtesy of Antony Wood,

CTBUH

Fig. 9. Burj Dubai Courtesy of Kyoung Sun Moon


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ducing appropriate construction modules, the structural and

faade systems become more critical for improved economy. Ex-

tracting regularity from an irregular building form and adjusting

the building form following the extracted regularity can be one

approach. Another approach may be to make the construction

modules relatively regular and design more adaptable connectionsso that they can accommodate any irregularity.

Structure, Faade, and Environmental Systems

From the viewpoint of technology, the emergence of tall buildings

began from the functional separation of structures and faades.

Iron/steel skeletal structures and the curtain wall concept replaced

traditional masonry walls, and the era for tall buildings began.

The functional separation of building structures and faades, how-

ever, did not accompany complete physical separation. Structural

and faade systems have always been constructed together with

physical contacts for their mutual benefit. The two systems, once

fully integrated with serious limitations when implemented in tallbuildings, have been relatively separated with minimum connec-

tions necessary to contribute to each other. Thus, new modern

ways of integration to accommodate new concepts have been de-

veloped. Some designers capitalize on portions or all of the struc-

tural and faade systems serving as prominent parts of the

building architecture Fig. 11 . Such decision on the part of thedesigner is a choice, though, and not a necessity.

Faades are typically supported by the primary structures at

the building perimeter. They provide enclosure for the building

and protect its interior from the outdoor environment. However,

structures are subjected to movements due to various reasons,

such as external forces, aging, and environmental changes. There-

fore, faades are designed and detailed to accommodate the struc-

tures movements without causing damage to the often delicate

faade material. Based on these fundamental interactions, the two

systems have developed toward each othersand in turnawhole buildings better performance. Architects and engineers are

in charge of developing better performance in these two indepen-

dent but very closely related systems.

Compared with heavy masonry walls, relatively light modern

curtain walls, typically composed of metals and glasses, allow

more visual and environmental connections between the exterior

and interior. More visual connections including introduction of

more natural light and great views into the interior space are

desired by architects and occupants alike. However, potential

harsh exterior environments require careful considerations for de-

sign and detailing of curtain walls. During the period when out-

door environmental conditions are unfavorable for human

comfort, maximum insulation value for the faade systems is de-

sired. On the other hand, for the periods when outdoor conditionsare close to the human comfort zone, faade systems may be

designed to allow use of the outdoor environment to generate

indoor comfort more economically. Further, faade designs that

permit free nighttime cooling through natural ventilation may be

considered. In such cases, structural systems and interior finish

designs should be carefully configured to augment the use of

thermal mass capacity. However, sometimes faade designs that

allow occupants control for natural ventilation create a dilemma

for designers. Some designers do not favor permitting occupants

access to outdoor air to avoid losing environmental control.

Among other things, access to outdoor air impacts control of

Fig. 10. Taipei 101 tuned mass damper Courtesy of Abbas Amin-

mansour)

Fig. 11. New York Times Tower in New York Courtesy of Abbas

Aminmansour


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stack effect also known as chimney effect phenomenon in tallbuildings.

Double-skin faades Fig. 12 can be an effective designchoice for tall buildings. They represent one of the most advanced

forms of contemporary building envelope systems. Properly de-

signed double-skin faades can successfully accomplish visual

lightness and transparency as well as better environmental control

than single-skin faades. Studies suggest that the productivity of

the occupants in the buildings clad with double-skin faades is

higher because of the more comfortable work environment these

faades can offer Oesterle et al. 2001 . However, usable area

reduction due to the cavity spaces, higher faade self-weight, and

more expensive cost of construction are some of the concerns to

be carefully considered in the design of double-skin faades.

An obvious function of building faades is to allow natural

light in the building, thereby creating a more comfortable envi-

ronment as well as reducing energy costs. Higher ceilings inbuildings with considerable glazing allow natural light to reach

deeper in the space, but add to the buildings overall height. The

depth of the floor sandwich may also increase the buildings over-

all height. Building floor sandwiches typically include floor

beams, girders, and slabs, as well as mechanical and other build-

ing components. Strictly from the structural point of view, deeper

beams are more desirable because of their potentially higher

bending strength and lower deflection. However, they too increase

the floor sandwichs thickness and add to the building height.

Increased building height results in additional use of material and

more space to condition during the life of the building. It also

increases the buildings exposure to high winds, which in turn

may require a stronger structure. Thus, decisions that increase

the buildings height must be carefully studied and made in col-

laboration with other team members.

Tall building perimeters are very important zones architectur-

ally, structurally, and environmentally. Thus, it is expected that

many building components are congested along their perimeter to

fulfill the necessary multiple complex functions. From the view-

point of structural behavior, it is quite desirable to concentrate as

much lateral load-resisting systems as possible on the perimeter

of tall buildings where building faades are located. This ideaincreases structural depth against lateral loads and increases the

systems efficiency. However, the idea may not be desirable in

terms of architectural and environmental control system design.

Nonetheless, observed from a slightly different angle, this could

increase the possibility of design integration because more ma-

neuverable components are concentrated at the same location.

Faades serve as the environmental mediator between the

building interior and exterior and are supported by the building

structure. If integrally designed, they can coexist with the struc-

ture without conflict and can enhance the performance of the

structural and environmental systems. Other building systems can

be designed in the same manner as well. With this approach, each

system is designed for its best performance while at the same time

actively participating in the enhancement of related systems per-formances. For this type of synergistic integrative design method-

ology, it is absolutely necessary for architects and engineers to

holistically understand the project.

Case for Sustainable Design

Over the last several years, sustainable design of buildings in

general has gained more attention from architects, engineers, and

constructors. Appropriately, sustainable design and construction

of tall buildings has become more popular among building pro-

fessionals as well. Given their enormous scale, the impact of sus-

tainable design and construction of tall buildings will beproportionately large. The number of tall buildings designed and

constructed around the world with sensitivity to our environment

and natural resources is ever increasing. The Hearst Tower in

New York City Fig. 4 , which opened in October of 2006, is thefirst office building in the city to receive Gold LEED certification.

The tower was built on top of the existing six-story Hearst office

building, which was built in the late 1920s.

The idea of placing a new building on top of an existing build-

ing or using portions of an existing building structure is not a new

concept. In Chicago alone there have been a number of examples

of such projects in recent years. The Dearborn Center, a tall build-

ing recently added to the citys skyline, was built on top of exist-

ing foundations built about a century earlier. Another example of

such projects in Chicago is the vertical completion of the HealthCare Service Corporation HCSC , also known as the Blue CrossBlue Shield building Fig. 13 . The project, which began in 2007,will add 24 stories on top of the existing 31-story tower built 10

years earlier with the future expansion in mind.

Using existing structures to build on top of saves material,

energy, and labor through reuse of existing constructed material.

However, these projects require careful investigation for ad-

equacy of the existing structure to accommodate new additions.

But in the end, in addition to the savings just mentioned, such

projects could bring the new project to completion earlier, thereby

generating considerable revenues for the owner as opposed to

Fig. 12. Double-skin faade design example Courtesy of Adam

Gimpert


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tearing down the building and constructing again.

A number of ideas may be included in sustainable design and

construction of tall buildings. One such idea is using highly inno-

vative and efficient structural systems that could save significant

material as opposed to conventional systems used in design of tall

buildings. Using materials that are recycled and/or more readily

available and processed locally as opposed to shipping them from

long distances is another example of sustainable design ideas.

Sensitive environmental systems design can have a substantial

impact on the sustainable design of tall buildings. With the ever-

increasing cost of utilities and our limited available natural re-

sources, energy-efficient tall buildings can save the environment

and our resources as well as offer big savings in the cost of

operating the building over its expected life. Creative and effi-

cient use of natural lighting as well as efficient heating, ventilat-

ing, and air conditioning systems are important factors in

realizing a sustainable design for tall buildings. Also, designing

tall buildings for better indoor air quality and a healthier environ-

ment is the right thing to do and could save considerable health-

care costs. The good news is that, contrary to what some believe,incorporating sustainable design ideas does not substantially in-

crease the cost of design and construction of tall buildings. Indeed

it is possible that the additional initial cost of sustainable design

and construction of tall buildings may be very minimal, if any.

Other ideas for responsible use of our natural resources in-

clude use of intelligent environmental system controls; energy

generation; energy efficient lighting and equipment; installing

sensors for control of lighting and other energy based fixtures and

equipment; energy efficient glass; use of construction materials,

furnishings, carpet, paint, sealants, etc. that are made of recycled

material and do not emit undesirable fumes; reuse of waste water

and collected rain water; and reducing the amount of walls and

partitions acting as barriers for natural light reaching deep inside

the building. Effective implementation of these and similar ideas

requires a collaborative and integrated approach by the design and

construction team.

Summary

Tall buildings are an integration of architecture, structural, and

environmental systems, and they require substantial resources to

build and operate. Therefore, design and construction of tall

buildings is a highly multidisciplinary process. To realize a desir-

able built environment through tall buildings, all professionals

involved in the design and construction of such projects should

work collaboratively from project inception to completion. Fur-

ther, operation and maintenance of the building after completion

must be taken into consideration during the design stage.

The knowledge, experience, and input that each team member

can offer throughout the design and construction process will add

substantially to producing a built environment that is creative,

environmentally sensitive, aesthetically pleasing, functional, andreasonable to construct, operate, and manage. Every team mem-

bers basic background and knowledge of aspects of tall building

design and construction beyond his/her own discipline is crucial.

It is true that the workload of individual design and construction

team members varies throughout the process, but every profes-

sional has a significant role to play at every stage.

References

Abalos, I., and Herreros, J. 2003 . Tower and office: From modernist

theory to contemporary practice, MIT Press, Cambridge, Mass.

Ali, M. M., and Moon, K. 2007 . Structural developments in tall build-

ings: Current trends and future prospects. Archit. Sci. Rev., 50 3 ,205223.

Baker, W., Korista, S., and Novak, L. 2008 . Engineering the worlds

tallestBurj Dubai. Proc., Council on Tall Buildings and Urban

Habitats, 8th World Congress: Tall & Green: Typology for a Sustain-

able Urban Future.

Connor, J. 2003 . Introduction to structural motion control, Prentice-

Hall, Upper Saddle River, N.J.

Moon, K. 2005 . Dynamic interrelationship between technology and

architecture in tall buildings. Ph.D. dissertation, Dept. of Architec-

ture, Massachusetts Institute of Technology, Cambridge, Mass.

Moon, K. 2008 . Optimal grid geometry of diagrid structures for tall

buildings. Archit. Sci. Rev., 51 3 , 239251.

Moon, K., Connor, J. J., and Fernandez, J. E. 2007 . Diagrid structural

systems for tall buildings: Characteristics and methodology for pre-

liminary design. Struct. Des. Tall Build., 16 2 , 205230.

Nordenson, G., and Riley, T. 2003 . Tall buildings, Museum of Modern

Art, New York.

Oesterle, E., Lieb, R., Lutz, M., and Heusler, W. 2001 . Double-skin

faades: Integrated planning, Prestel, Munich, Germany.

Russell, J. 2003 . Architectural style and management ideals, AV Mono-

graphs 103.

Smith, B., and Coull, A. 1991 . Tall building structures: Analysis and

design, Wiley, New York.

Fig. 13. Vertical expansion of the Health Care Service Corporation

building in Chicago Courtesy of Abbas Aminmansour


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