TABLE OF CONTENTS

CHAPTER 1 – DESIGN SECTION 1.1 HISTORY

SECTION 1.2 CONCEPT

SECTION 1.3 VISUAL ANALOGY

CHAPTER 2 STRUCTURE SECTION 2.1 LOADS

SECTION 2.2 COMPONENTS

CHAPTER 3 CONSTRUCTION SECTION 3.1 THE PYLON SECTION 3.2 MATERIALS SECTION 3.3 RESULTS & ENVIRONMENTAL IMPACTS

CHAPTER 1 | DESIGN

HISTORY | BACKGROUND

The Alamillo Bridge was commissioned by the Junta de Andalucía for the celebration of the Universal Exposition in Seville, Spain of 1992. No bridges had been built over the Guadalquivir River since 1964. The bridge was part of a new roadway linking western villages together as well as serving as one of the three main access routes to the World exposition. The architect chosen to design the bridge was Santiago Calatrava. He is a Spanish engineer and architect. He was commissioned to build the bridge due to a provision in Spanish law stating that; direct commission can be given to prominent architects of international recognition without an official competition. (Pollalis, 1999)

“The Alamillo Bridge is the most important piece of work that the Junta de Andalucía has built on the occasion of Expo ’92… The bridge does not simply offer [transportation] service to the city, it is one of the most important architectural monuments that will remain after Expo ’92 is over.” - Manuel Chaves, President of the Junta de Andalucía. (Pollalis, 1999)

DESIGN | CONCEPT

The concept for the bridge can be traced back to Calatrava’s 1986 “running torso” sculpture. In this sculpture stacked marble cubes were balanced by one tension wire. Throughout his career the natural forms in movement have inspired him. (Holm, 2006)

“One draws the human body to understand the movement, the gesture. The space, the landscape, the human landscape, and topology are important for me. These will inspire or bring the essence -to a project. So, for myself I venerate the human body.” (Pollalis, 1999)

The original design was approved as two symmetrical bridges. The used of this design principal was propelled by the symmetry of the riverbanks themselves. Unfortunately due to the projected cost of construction, the Junta de Andalucía challenged Calatrava to design only one bridge and thus began the journey to reconcile his asymmetrical single pylon design. (Pollalis, 1999)

VISUAL ANALOGY

Visual thinking and visual analogy have always been seen as important aids in design problem solving. Designers are frequently assisted by visual stimuli to enhance their designs. (Holm, 2006) Visual displays play an important role in the early stages of the design process, where visual analogy is considered to

have large significance. In the case of the Alamillo Bridge, Calatrava employs the visual analogy of the Brooklyn Bridge’s elevated pedestrian walkway. The roadway itself is cantilevered out from the beam. The bridge not only becomes a form of transportation but the parks build at its base welcome travelers to utilize its urban public space. Much like the Brooklyn Bridge’s design, all the vehicular and pedestrian traffic is on one side of the bridge. "This is possible because of the torsion stiffness of the bridge itself. It drives the vocabulary of bridging and gives a little more sensibility in terms of orientation and placement, and in creating a kind of sculptural effect for the bridge." The bridge therefore becomes a symbol of the city and its inhabitants. (Casakin, 2004)

CHAPTER 2 | STRUCTURE

LOADS

The single plane of cables support a beam down the middle of the road, maintaining the bridge's image of a harp.

Live Loads: A combined 408 kilograms = 899.48603 pounds plus 600 Kilonewtons (kN) of vehicular traffic were considered in the estimate of the bridge’s live load.Dead Loads: The weight of the pylon and deck at ratio of 9 times the live load. Thermal Loads: Are caused by the changing temperatures of the elements of the bridge. These changes cause expansion and contraction of the bridge’s materials. Between the summer and winter months the bridge experiences a thermal difference of approximately 46 degrees Celsius.Wind Loads: Spanish code OM/28-2-72 suggests the anticipated protection from a maximum wind velocity of 50 meters per second. During the planning of the bridge, Engineers used a 500-

year wind velocity projected profile to estimate future wind turbulences. In a bridge especially, there is special consideration to uplifting wind loads. (Salvadori, 1980)

STRUCTURAL COMPONENTS

Santiago Calatrava tries to express a dynamic movement of the static members in his structures. The Alamillo Bridge demonstrates this intention with the concrete-filled steel pylon inclined at 58 degrees. The pylon is divided internally into several pieces and its accumulated

structure allowed the weight of the pylon to counterbalance the car deck below. Like a counterweight, the inclined pylon is anchored in the 142-meter tall.

In this process, Calatrava created a new type of cable-stayed bridge. A typical cable-stayed bridge has an “A” shape design. Most of these types of bridges do not require two towers like their suspension bridge counterparts. Instead, the cables are run from the roadway up to a single tower where they are secured. Calatrava’s design was revolutionary as it was the only cable-supported bridge that was not back-anchored. The Alamillo Bridge is balanced solely through added weights in the Pylon. Thus, the Pylon experiences a constant bending moment.

(Janberg, 1992)In addition much thought and engineering was planned and thus resulted in the use of 51 nodes, 50 beam elements, and 13 pairs of cable components. The Cable Stays transfer loads from the deck to the pylon. A single cable alone can support the corresponding weight carried by its symmetrical counterpart. This allows for parallel cables to be replaced individually. (Pollalis, 1999, p. 105)

The Deck of the bridge is comprised of a continuous steel box that spans the length of the bridge: with supports at every 12 meters. The vehicular lanes are cantilevered off this deck and are made from reinforced concrete cross sections. These cross sections enhance the torsion and bending strength of the steel box as it withstands various loads.

The Dimensions of the Bridge are as follows:Main deck span-250 metersPylon height-162 meters

The Foundation supports all of the external loads of the bridge. This bridge relies solely on a single support at the foundation of the pylon to withstand load changes. (Pollalis, 1999)

CHAPTER 3 | CONSTRUCTION

THE PYLON

The Alamillo Bridge Completed in just thirty-one months. It was completed in 24 phases.

Construction began with the foundation. It is composed of 54 reinforced concrete piles. Each is hydraulically hammered and thus embedded into the marlstone. The pedestal and pylon were constructed with the use of steel caissons. They were mounted one on top of the other and slowly filled with reinforced concrete. After the concrete hardened, the cable stays were attached to that segment of the pylon and the subsequent caisson was lifted and positioned in place. The Deck was positioned as reinforced concrete road slabs (Pollalis, 1999)

MATERIALS

Calatrava was careful to choose the appropriate materials for the bridge. The exposed materials are dressed in either steel or concrete. The steel and concrete surfaces are painted white, and the main cables are also placed inside white polyethylene tubes. The only part of the bridge that is not white is the pedestrian handrail. This stainless steel element invites pedestrians to touch and interact with the bridge.

"New materials like steel, welding and other techniques, combined with our modern understanding of torsion, allow us a lot of new possibilities." (Makker, 2003)

RESULTS & ENVIRONMENTAL IMPACT

The design of the bridge allowed for the riverbanks to remain unobstructed. This not only allows for the natural flow of the Guadalquivir River, but it minimizes the environmental impact to the ecosystem it harbors. Furthermore, the bridge has become a source of pride for the people of Seville. People enjoy crossing the river and enjoy the views of the river and the city. The bridge has given citizens urban space with special consideration of the pedestrian walkways. Although the total cost of the bridge was $4,760.00 per square mete. The bridge is now an extension of Seville and part of its urban context. (Pollalis, 1999)

“The Alamillo Bridge holds a minimalist approaching the Problem of equilibrium by using a minimum of elements," Allowing an onlooker "to see a pattern of readability and reflection of those objects." – Santiago Calatrava.

BIBLIOGRAPHY

Casakin, H. (2004). Visual Analogy as a Cognitive Strategy in the Design Process. Expert Versus Novice Performance   . Journal of Design Research , 4 (2), 6.

Holm, I. (2006). Ideas and beliefs in architecture and industrial design: how attitudes, orientations, and underlying assumptions shape the built environment. Olso School of Architecture.

Janberg, N. (1992). Structurae. Retrieved 2010, from http://en.structurae.de/structures/data/index.cfm?id=s0000002

Makker, K. (2003). Spotlight on Design Lecture. National Building Museum , 4.

Pollalis, S. N. (1999). What is a Bridge?: The making of Calatrava's Bridge in Seville. Athens, Georgia: MIT.

Salvadori, M. (1980). Why Buildings Stand Up. New York: Norton.