Hearst Tower: The Diagrid Diamond Revitalizing Manhattan

Series: Avant-Garde Constructions

Masterpieces of Architecture and Engineering: #04 Hearst Tower, New York

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How do you build a glass colossus upon a stone pedestal left orphaned by the Great Depression?

In 1928, Joseph Urban completed the construction of the Art Deco base for the Hearst Corporation headquarters. Although this six-story building was originally engineered to support a skyscraper, the economic circumstances of the 1929 Great Depression prevented the completion of the projected tower. Eighty years later, Norman Foster and WSP Cantor Seinuk not only fulfilled that dream but did so by breaking a sacred rule of architecture: they eliminated vertical perimeter columns.

Giant Surgery: Megacolumns vs. Art Deco

Following the wounds of 9/11, New York didn’t just need another building; it needed a manifesto of resilience. The Hearst Tower represents extreme urban surgery: the heart of the original monument was hollowed out, leaving only a six-story historical "shell."

To prevent the new tower from crushing the past, high-strength steel megacolumns were inserted, piercing the ancient base like surgical needles. The result is a colossal atrium where the tower appears to levitate above a 25-meter-high structural void.

The best architecture comes from a synthesis of all the elements that compose a building: the structure that supports it, the services that allow it to work, and the ecology of the building.

— Norman Foster

The "Diagrid": The Absolute Geometry of the Triangle

Forget the traditional orthogonal grid. The Hearst Tower relies on absolute triangulation. This diamond-shaped exoskeleton, known as Diagrid, is not an aesthetic whim; it is the purest form of physical efficiency:

The Triangle is Non-Deformable: While a rectangular frame deforms under lateral wind pressure, the triangle locks. This provides the tower with a torsional rigidity that a conventional skyscraper could only dream of.

Radical Material Saving: By allowing the diagonals to carry the full load (both gravity and wind), corner columns were eliminated. The result: 2,000 tons of steel saved (20% less than a standard building).

Uncluttered Views: With no perimeter pillars, the office floor plates are open fields. The steel does not block the view; it frames it.

The reliability and precision of the diagrid system in the Hearst Tower can be compared to that of a Swiss watch; my work has always been about stretching the horizon.

— Ysrael Seinuk, Structural Engineer (WSP Cantor Seinuk).

The Transfer Platform: The Gordian Knot

The most critical point of this engineering feat occurs on the seventh floor. Here, the Diagrid terminates and must transfer thousands of tons of diagonal loads into the vertical megacolumns that lead to the foundation.

A massive transfer platform was designed—invisible to the human eye, but vital for the building's structural integrity. It is at this junction where the physics of the diamonds yield to gravity, channeling forces into the ground without ever touching the 1928 historic facade.

"Icefall": The Water-Driven Lung

In a conventional skyscraper, HVAC systems face a losing battle against solar gain. In the Hearst Tower, the building "breathes." The "Icefall" water sculpture is not merely decorative; it is a psychrometric machine:

Evaporative Cooling: It utilizes harvested rainwater to naturally cool and humidify the atrium.

Radiant Flooring: This marked New York's first large-scale use of a capillary tube network beneath the floor, radiating cooling or heating while eliminating the noise and energy consumption of massive air handlers.

Other Issues in the Series:

ISSUE #01 | Burj Khalifa: The Wind Code
Stepping technique: how geometric variation tames vortices at 828 meters.

ISSUE #02 | CCTV Tower: Defying the Void
Beijing's most ambitious cantilever and the structural steel diagrid-grid that supports this continuous loop.

ISSUE #03 | Taipei 101: Dynamic Balance
Defying typhoons and earthquakes with the iconic 660-ton tuned mass damper.

ISSUE #08 | Fountain Place: Geometry in Motion
The polyhedral rigor of Henry N. Cobb: how a 10-faced prism achieves the dematerialization of architectural mass.

View Full Series Roadmap →

Battle of the Titans: Technical Comparison

Turning Torso (Malmö), 190 m: Achieves stability through a circular reinforced concrete core and an external steel "spine" that enables the 90-degree rotation of its floor plates.

CCTV Beijing (Beijing), 234 m: Defies gravity through a continuous loop design and an irregular structural skin that distributes stresses across an extreme cantilever.

Hearst Tower (New York), 182 m: Relies on the intelligent geometry of the Diagrid. By utilizing 85% recycled steel and eliminating corner columns, it proves that the avant-garde is not just about height, but structural efficiency.

Technical Datasheet & Team: Hearst Tower NY

Project	Hearst Tower
Location	8th Avenue at 57th Street, Manhattan, NYC
Architecture	Foster + Partners (Norman Foster)
Structural Engineering	WSP Cantor Seinuk (Ysrael A. Seinuk)
Height / Floors	182 m / 46 stories (incorporating the original 1928 base)
Structural System	Steel Diagrid Exoskeleton (Perimeter Triangulation)
Certification	LEED Gold (NYC's first sustainable skyscraper)

Industrial Specs & Solutions | Project Brands

AECO VERIFIED

Component	Brand / Provider	Technical Execution & Application
Structural Steel	Cives Steel Company	Fabrication of Diagrid nodes using 85% high-strength recycled content for structural sustainability.
Curtain Wall (Façade)	Permasteelisa Group	Unitized façade featuring complex "bird's mouth" geometry integrated into the diamond vertices.
Vertical Transportation	Schindler	Intelligent management via the Miconic 10® system for predictive optimization of passenger traffic flow.
Climate Systems	Fluidity Design	Engineering of the "Icefall" cascade designed for humidification and passive cooling of the central atrium.
Fastenings	Hilti	High-performance anchoring systems for critical load transfer at the Level 7 transition node.

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Frequently Asked Questions about the Hearst Tower, New York:

How does the 1928 base support the weight of the new tower?
In fact, it does not. Joseph Urban's original structure was hollowed out and acts only as an aesthetic shell. The weight of the glass tower is transferred directly to the ground through steel megacolumns that pierce the ancient base without resting upon it.

Why was 85% recycled steel chosen for the project?
It was a pioneering decision for New York skyscrapers to achieve LEED Gold certification. By combining the geometric efficiency of the Diagrid (which uses less material) with recycled steel, the building's carbon footprint was drastically reduced.

What technical function do the "diamond birds" (chamfers) serve?
The cut vertices at the tower's corners are not merely aesthetic; they serve to disrupt wind turbulence. By softening the corners, lateral pressure is reduced, preventing the oscillation effect caused by vortex shedding.

How does the "Icefall" climate control system work?
The lobby water feature utilizes rainwater harvested from the roof. This water helps to humidify and cool the air in summer through evaporation, working in conjunction with radiant flooring to optimize energy consumption.

Is the Diagrid system safer than a conventional one?
Yes. The redundancy of the triangular system offers superior torsional stability. If a node were compromised, loads are naturally redistributed through adjacent diagonals—a process that does not occur as easily in vertical pillar structures.

AECO AECO Glossary of Architecture & Engineering | Hearst Tower, NY

Diagrid (Diagonal Grid): A structural design framework of diagonally intersecting metal, concrete or wooden beams that forms a triangular grid. It eliminates the need for traditional vertical perimeter columns, optimizing resistance to both gravity and lateral (wind) loads.

Transfer Node: A critical engineering junction located at the 7th Floor where diagonal loads from the diagrid system are channeled into the massive vertical steel megacolumns that penetrate the 1928 historic base.

Bird’s Mouth (Chamfers): The V-shaped notches cut into the corners of the tower. These serve a vital aerodynamic function by breaking up wind flow and reducing vortex shedding, which minimizes building oscillation.

Icefall: A three-story glass water sculpture in the atrium that functions as a passive cooling system. It utilizes harvested rainwater to humidify and cool the lobby air through evaporation.

Radiant Floor: A climate control system using a network of PEX tubing embedded in the floor. In the Hearst Tower, the atrium’s concrete floor acts as thermal mass to radiate heat or cooling efficiently, reducing fan noise and energy consumption.

Torsional Rigidity: The structural capacity to resist twisting forces around the vertical axis. The inherent geometry of the diagrid provides superior stability against the asymmetric wind pressures typical of the Manhattan skyline.

Unitized Curtain Wall: A facade system where large glass units are pre-assembled in a factory and then installed. It features high-performance glazing that filters solar radiation while maximizing natural daylight harvesting.

Series: Avant-Garde Constructions | jmhdezhdez.com

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José Miguel Hernández Hernández

International reference in the technical analysis of iconic and sculptural architecture. Specialist in the intersection between engineering, aesthetics, and vanguard design. Author of the bilingual technical books Turning Torso – Santiago Calatrava and Famous Constructions.

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