Completed in 1931 in just 410 days, the Empire State Building rises 102 stories above Midtown Manhattan. For nearly 40 years it was the world’s tallest building – and a global symbol of the industrial era. Built of limestone and steel in the distinctive Art Deco style, it has been named as one of the Seven Wonders of the Modern World. But what if this monumental high-rise was made of wood? Is that even possible?
The Empire State Building stands in stark contrast to modern wood-built buildings, which are rarely higher than four stories - mostly due to building codes and outdated misconceptions according to architect Michael Green. In Vancouver, where Michael Green Architecture is based, trees grow to 33 stories tall. And in California, the redwood forest grows to 40 stories tall. A tree’s growth is only limited by its ability to push nutrients up its height, and not by the structural capacity of its fibers.
Green is a strong believer that high-rise wooden buildings are not only possible, but may be the most practical and environmentally sound solution to rapid global urbanization and climate change. To test the theory that high-rise wooden construction is a practical possibility, Green, along with Metsä Wood, a Finnish wood products producer, recently designed the Empire State Building using wood as the main material.
The project is part of Metsä Wood’s “Plan B” campaign aimed at promoting wood as a serious option in everything from design to construction – also in buildings in which wood hasn’t previously been used, like skyscraper construction. The design and construction plan for a wooden version of the Empire State Building was spearheaded by Green and his firm MGA. An internationally recognized leader in timber engineering, Equilibrium Consulting, provided expertise on structural matters. Metsä Wood’s own material and construction experts rounded out the team.
“While many things have changed in 85 years, architects still strive to give form to new ideas about structure, energy consumption, climate change and the list goes on. For these reasons the most iconic building of the modern age - the Empire State Building - was chosen for the Plan B case. We designed a skyscraper using Metsä Wood’s Kerto LVL engineered wood as the main material from floors to column spacing,” explained Green.
Misconceptions about tall wood buildings are beginning to change. In the past few years the world has seen the construction of wooden buildings up to 100ft (30m) tall, setting records that will soon be broken by new projects under way that will reach as high as 250ft (75m), like the Barents Secretariat Tower in Norway.
Green believes that wood is not only a highly aesthetic and sustainable option but also efficient, fast to construct and enables light structures. And it may also be more fireproof than usually perceived. “I believe that the future belongs to tall wooden buildings. Significant advancements in engineered wood and mass timber products have created a new vision for what is possible for safe, tall, urban wood buildings. The challenge now is to change society’s perception of what’s possible. In fact, this is the first new way to build a skyscraper in the last 100 years”, added Green.
The challenge with the Empire State Building project was to design a building out of wood five times taller than anyone has dared to imagine; to design an iconic building, representative of innovations in structural steel in the 1920’s, out of engineered wood panels.
In Green’s design, the overall building size, floor to floor height, and column spacing are the same as the original structure. The columns extend as much as 6 stories high, with moment connections at these locations to make each column structurally continuous up to 86 stories. Box beams connect the column along the short axis of the building. Four pretensioned cables run within these beams, tying the structure together from side to side. Kerto LVL slabs span the long axis of the building connecting the beams together and forming the top cord of the beams.
Plan B challenges widely spread preconceptions and explores the various possibilities of wood construction. As a part of the project, Metsä Wood shows in detail how to build a recognizable yet modern versions of world-known architectural buildings using wood as the main material. The concept’s main target groups are architects, construction engineers and builders.
“Wood construction is an ever-evolving business, and the market needs more innovative, sustainable, faster and effective solutions,” explains SVP Jari Tikkanen from Metsä Wood. “Metsä Wood is strong in Europe, with ambitious global growth targets in USA and Asia.”
As Metsä Wood’s website notes, when the first skyscraper was built, people were terrified to walk beneath it. Significant advancements in engineered wood and mass timber products have created a new vision for what is possible for safe, tall, urban wood buildings.