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About this Article
Written by: Eric Nakasako
Written on: July 10th, 2008
Tags: civil engineering, building & architecture
Thumbnail by: MarkusMark/Wikimedia Commons
About the Author
In Spring 2008, Eric Nakasako was a Junior majoring in Chemical Engineering at the University of Southern California. He discovered his interest in the city of Venice while studying abroad in Rome, Italy.
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Volume X Issue IV > A Look at Venice: Past and Present
The city of Venice is an engineering masterpiece. From the well-known St. Mark's Square to the infamous Bridge of Sighs, the city was built entirely on water. The early engineers of the city had to choose specific materials suited to marine conditions, and they developed unique techniques for constructing the historic buildings we see today. However, the precious city of Venice has begun to sink at an alarming rate, threatened by increasing water levels and ever-frequent flooding. The proposed solution to the problem is the MOSE project, consisting of 79 mobile floodgates that will, when raised, seal off the lagoon from the Adriatic Sea, thus preventing unusually high tides from damaging the city. As we take a look at the history of Venice, from its original planning and construction to the new problems it faces today, we will see how understanding the city's engineering past may provide the means to preserving it for generations to come.
Venice! Venice! When thy marble walls are level with the waters, there shall be a cry of nations o'er thy sunken halls, a loud lament along the sweeping sea! Lord Byron [1]

Introduction

Lord Byron's prophetic verse from his poem "Ode on Venice," captures the sentiment felt by many who have walked the streets and seen the fabled canals of Venice, Italy. Unfortunately, Venice has been plagued by sinking foundations and rising water levels that threaten to destroy this engineering wonder. This has spurred an international effort to save the city of Venice from becoming a watery grave. By learning about Venice's planning and construction, while also observing Venice's present challenge of solving its flooding problems, we will better understand how it is necessary for engineers to continually adapt to solve the unprecedented challenges that Venice faces.

The Foundations of Venice

The city of Venice was built in the early 1500's A.D. on a collection of 117 low islands at the center of a lagoon. The numerous canals provided an ideal location for a city because they formed a natural defense against foreign attackers, similar to a moat [2]. In order to build a city above the water, early architects had to build stable foundations that were sunk deep into a bed of compounded silt and sand called subsoil. The construction material of choice for these foundations was wood stakes from native alder trees [3]. Wood made an ideal foundation material because the submerged wood was not exposed to air, which inhibited deterioration and rotting. In addition, the wood provided a strong, yet flexible support that could resist the constant movement of the tides [3]. These alder stakes supported a horizontal wooden platform of elm and larch (called zatterone, or "large rafts"), where foundation walls of large stone blocks were built.
MarkusMark/Wikimedia​ Commons
Figure 1: A city built on water, Venice is a historic example of engineering solutions. Modern-day Venice poses new problems of aging infrastructure and rising sea levels.
These foundation blocks were made of a type of stone called Kirmenjak. Its unique properties - extremely low water absorption and high strength to support large buildings without weakening - made it an ideal material for Venetian foundations. This prevented water from creeping up through the stones (called rising damp) and into the vulnerable brickwork [4]. Atop these stable foundations, architects built the magnificent buildings we see today, which are made of brick and often have marble facades. The foundations of Venice provide a great example of the specific planning and careful material choices that made this city-on-the-water a reality (see Fig. 1).