Calatrava Essay, Part 3

CALATRAVA bridges

As a body of work, one of the most remarkable things about Calatrava's bridges is the diversity of their forms, structural ideas, and materials. This is particularly true in comparison to Freyssinet and Maillart, whose bridges are visually similar and easily attributable. Calatrava's bridges do have a lot in common, however. Their similarities are based in their shared concepts, rather than in their literal forms and materials. Calatrava's bridges suggest four common ideas: they all represent a break with the idea of a bridge as a technical-utilitarian artifact; they use structural principles, materials, and construction methods as springboards for formal expression, rather than for creating the monumental expression of a structural paradigm; they are designed as architectonic mega-sculptures, not as simple pathways; and they celebrate the role of bridges as civic icons in the urban landscape. By exploring these ideas in overlapping, complex ways, Calatrava creates structures that defy conventional classification.

Calatrava's design ideals both distinguish him from his contemporaries and provide him with a new and iconoclastic conceptual model of what a bridge should be. His ideals also suggest a new direction for the art of bridge design. Calatrava's success in pursuing this new direction is attributable to many sources, but being in the right place at the right time has possibly helped him most of all. His opportunities have depended on the altruism of his Western-European clients and their view that the infrastructure should be used to make civic gestures. Eleven of Calatrava's almost thirty bridge projects were first designed as competition entries. Similar competitions are routinely held by communities throughout Western Europe to help them meet their utilitarian needs and improve their public spaces. Cost is certainly an issue in these venues, but often the most technically-efficient entry is passed over for a technically-plausible entry that also addresses other urban issues more completely.

Europe's emphasis on the symbolic importance of its infrastructure stands in stark contrast to the U. S., where there is little association between cultural vision and civic engineering. Competitions for bridges, except to help decide the lowest cost structure, are virtually unheard-of in America. The commissioning of infrastructure works in the U. S. is driven by a kind of economic rationalism, in which the least expensive solution is considered not only the most meritorious, but often the only acceptable one. From this puritanical point of view, "design" embraces only the most narrowly defined issues of technology and utility, and the resulting structures are reduced to mere commodities. Predictably stodgy and often ugly, these products fall short of their potential to convey technical elegance or stimulate visual interest.

typical and predictable design

The American system has effectively kept Calatrava from attempting to build a bridge in the States, although he has been asked to submit preliminary designs on at least two occasions. Calatrava's approach has been more welcome in American architectural circles, as demonstrated by his recently receiving the competition-determined commission for the completion of a portion of the Cathedral of St. John the Divine in New York City.

Besides being helped by the design climate in Europe, Calatrava also benefits by the revolutionary post-war advances in computer technology and related fields. Numerical methods, computational techniques and automated graphics systems quickly provide contemporary engineers with an unprecedented wealth of analytical information about a proposed structure. The structural analyses of turn of the century designers were restricted to closed-form, analytical solutions provided by classical physics and differential calculus. Determinant structural types (forms whose forces can be found by applying the laws of static equilibrium alone) were employed in the design of most major civil engineering works, as seen in such disparate structures as Maillart's Salginatobel Bridge and Contamin's Gallerie des Machines. [33] and [34] Determinant types were used because the solution of an indeterminant structure'smetimes critical calculations of deflection, the mathematical difficulties posed by indeterminant structures were often insurmountable. In an epoch when the most advanced numerical aide was a slide rule, using a three-hinge system for the Gallerie des Machines and the Salginatobel Bridge arguably made possible the computations required to ensure their safety.

Salginatobel Bridge

Gallery des Machines

Similarly, analytically described geometries were often the easiest and sometimes the only shapes which could be analyzed easily and constructed full-scale from design drawings. The form of the Salginatobel Bridge, for example, was both inspired and limited by the methods of structural analysis available to Maillart. As David Billington points out, in addition to working with determinant systems, Maillart chose forms for which he could justify critical assumptions about the behavior of his bridges, which made their analysis and design relatively simple. [35] In the pre-computer era, problems of determinance and geometry effectively limited the possible forms of civic engineering commissions to either representations of existing structural types, or - as in Maillart's case - the creation of new ones.

Today, the rise of the Finite Element Method of structural analysis, and the Stress Field Theory for simplifying reinforced concrete calculations have made the structural analysis of any form essentially only as difficult as the problem of representing a structure's geometry and loading. Parallel developments in computational and presentation graphics have made non-analytic geometries easy to represent. While many engineers have taken advantage of these developments simply to represent and analyze a structure more expediently, Calatrava uses these technologies to develop his complicated geometries and ensure their structural plausibility.

Calatrava has also avoided the loss of structural design skills sometimes associated with the extensive use of computers. As has been often noted by older engineers, the use of computers to the exclusion of "by-hand" analytic methods has resulted in the loss of a qualitative feel for structural behavior. This is an especially ominous development because some of the best engineer's attribute their success to their qualitative grasp of structures. It has been reported that the master engineer Felix Candela, for example, advocates "the intuitive feeling in the old cathedral master . . . for handling material and forces." [36] Calatrava's clear qualitative grasp of structural behavior is illustrated by his ingenious solutions to the arch-buckling problems of the Bach de Roda, Ripoll, and East London River Crossing bridges. His feel for structural proportion is the stuff of legend among his engineering staff, who more often than not do not need to modify the size of the components depicted in his early sketches.

Calatrava's bridge-design practice also flourishes in part because he applies both his broad architectural and engineering training to his commissions. Calatrava's facility with structure, form and program makes him an ideal individual to design civic engineering works, and he has few similarly trained competitors. Most of today's structural and civil engineers have a narrowly defined, almost exclusively technical education, which limits their ability to tackle many larger design issues. The highly specialized engineering education and professional practice are largely responsible for this. A typical engineer's undergraduate training in the U. S., for example, includes five one-semester courses in liberal arts and usually includes no introduction to the problems of site, program and context. A typical graduate program for a master's degree has no room for courses outside structural theory, technical design and construction techniques. Graduate training in Europe is similar. Engineering careers have also become increasingly specialized, to the point where a single individual may devote his entire career to the application of one material in either civil engineering or building commissions. This system encourages engineers to develop only very limited design skills, and has resulted in today's ironic situation in which the professionals entrusted with the creation of a significant portion of our built environment are unprepared to consider its compositional and programmatic aspects.

Calatrava's contributions to the field of bridge engineering suggest consideration of his methods as a new paradigm for civil engineering practice. In a time when design professionals are grappling with the increased complexity of their disciplines by specializing, Calatrava's approach suggests that by focusing on a particular field, a designer with a broad background can paradoxically produce a richer, more compelling body of work than those trained exclusively in that field. A general extension of Calatrava's methods, however, should of course be approached carefully. Calatrava is a quick learner who has unusual facility in a number of disciplines; most designers do not have the time, or arguably the talent, to become so well-rounded. Few engineers or architects can muster the range of skills needed to work in Calatrava's ouvre. Frenchman Marc Mimram is one of a handful of Calatrava's contemporaries who are trained as both engineer and architect, and can compete with Calatrava without the help of consultants. In 1991, Mimram received 2nd prize in the competition Calatrava won for a bridge over the river Spree in Berlin. [37]

Bridge over the River Spree

Wabasha Bridge

Wabasha Bridge

The ability to treat bridge designs as opportunities for structural invention, while enriching them both formally and programmatically has been successfully pursued more often by architect-engineer teams. James Carpenter, who studied architecture at the Rhode Island School of Design before taking a degree in sculpture, recently accepted a commission to design a bridge over the Mississippi river in St. Paul, Minnesota. [38] Carpenter is working out the structure's conceptual details with engineer Joerg Schlaich, and will entrust the preparation of its construction documents to Sverdrup Engineers. Working with another engineer (Peter Rice), Richard Rogers took second place in Paris' Gentile Bridge competition over the Seine in 1987. Rogers' team approach to bridge design follows his proven success in working collaboratively on programmatically more complex commissions. Rogers, who feels that "use of new technologies and sculptural, rather than decorative composition [are] some of the most enduring legacies of the Modern Movement," [39] sees technology and spatial design best pursued collaboratively. He says "our office calls together all the relevant specialists, including consulting engineers, the moment we get a project." [40] This collaborative model is clearly more accessible to most architects and engineers than embodying both sets of skills in one person, and is probably necessary in solving the more complicated problems of large architectural commissions.

Cost also provides a basis for questioning the extension of Calatrava's methods to mainstream practice. Some of Calatrava's bridges are relatively inexpensive. The Ripoll Bridge, for example, cost about $700,000, and his design for the East London crossing is estimated to cost at most 10% more than a standard box-girder bridge. [41] But as often as not, it seems "if you want a bridge by Calatrava, you have to pay for it," as one of his staffers says. Escalated costs are sometimes an inevitable and understandable byproduct of new and unique structures. On the other hand, many of the twentieth century's best civic engineering achievements have been obtained through competitions whose judges selected winners proposing elegant and inexpensive structures. Pier Luigi Nervi's exquisite Italian State Monopolies Warehouse project in Tortona Italy, for example, was selected for construction through a competitive bidding process, as were many of this other projects. [42], [43] Many of Maillart's and Freyssinet's commissions were obtained by similar means. Maillart's Salginatobel Bridge is perhaps his most famous example. While Europe's cultural climate has nurtured Calatrava's career, its heritage demonstrates that commissions obtained by cost-based competitions need not be banal.

Turin Exhibition Hall

Calatrava has also of course experienced his share of problems in executing his bridges. For example, Dragados y Construcciones SA, the Alamillo bridge's contractor, claimed that the change in the bridge's tower from slip-formed concrete to a concrete filled steel shell was not just a construction expedient. Dragados maintained that Calatrava's proposed, slip-formed construction method was unbuildable, and that the cost of the bridge was much more than predicted. [44] The modification in the tower's design was partially responsible for Dragados' claims of escalated costs.

The difficulties Calatrava has experienced in realizing some of his larger projects seem inevitable in the face of the vast amount of knowledge required to practice - let alone innovate in - the art of civil engineering. Joerg Schlaich reflects a commonly held view when he says "if you want to be a structural engineer who can contribute innovative ideas and doesn't want to be repetitive, then you have a life's work keeping up with the developments in the field." [45] Presumably one's work improves with experience over time. By this test, Calatrava is "too young to be a good engineer. But he can catch up." Schlaich certainly has a point. The complexity of the structural engineering (and architectural) fields is in-part responsible for the collaborative design process being pursued by Rogers and others. Today, because there is so much for an engineer to learn about structures, it is commonly accepted that his technical education is just beginning when he completes his university studies. As Schlaich points out "At the end of his studies, a structural engineer is happy if he can [design] a beam on three supports in prestressed concrete. If you introduce a cable or a complicated support, he will be lost." [46] In the face of this complexity, structural innovations are often the result of years of thought and refinement by the brightest professionals, who frequently work almost exclusively with one structural material. Maillart's extraordinary advances in reinforced concrete construction bear testimony to this; his new structural forms were developed over the course of years, and were applied primarily to reinforced concrete bridges. Calatrava's most ambitious works also underscore this truth. His most innovative construction scheme (for the Alamillo Bridge) was borrowed from techniques developed by Baumgart and Finsterwalder more than 30 years earlier. When carefully scrutinized by those who specialize in building the designs of others, it was rejected as impractical. Also, some of the most advanced structural analyses of Calatrava's bridges (for example the arch buckling studies produced for the Bach de Roda and Ripoll bridges) were performed with computer programs whose details are understood by only a handful of theoreticians.

Viewed more broadly, Schlaich's analysis of Calatrava misses the point. It is based on the assumption that engineering innovation is the goal. But unlike those who proceed him, Calatrava has not tried to specialize in the pursuit of structural innovations in a strict technical sense. He has trained himself more generally, combining his architectural background and artist's sense of form with his engineering skills. Bringing all his training to bear, Calatrava approaches his work from a wide perspective. This perspective gives him the opportunity to advance the field of bridge design in a broader sense than that embodied in the technical progress of his predecessors.

The breadth of Calatrava's interests, of course, prevents him from pushing the structural state of the art, or grappling with programmatically complex commissions on his own. In one sense, this makes Calatrava a specialist while it prevents him from innovating. But in a larger sense, he becomes both a generalist and an innovator. By addressing the issues of technology, program and formal expression, he becomes a generalist in his domain. By successfully synthesizing these elements in his work, he transforms utilitarian civil engineering structures into both sculptural statements and important public spaces. In executing this transformation Calatrava becomes an innovator in a design field that is neither architectural nor structural but is richer than either alone. Equally important, he does not forfeit the use of the technical state-of-the-art or forgo the ability to work on architecturally complex commissions with collaborators. But most important is the fact that his bridges exist.

La Devesa Footbridge
Their presence challenges us to re-evaluate our infrastructure's civic potential as they provide a basis for questioning the brief of the professionals who design it.

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Calatrava Bridges, images


Footnotes

[33]Salginatobel Bridge. Robert Maillart.

[34]Gallery des Machines. Contamin and Dutart.

[35].Billington, Robert Maillart's Bridges. p 92.

[36].Werner Blaser, ed, Santiago Calatrava: Engineering Architecture. Page 11.

[37]Bridge over the River Spree, Berlin. Marc Mimram. Competition entry, 1991.

[38]Wabasha Street Bridge, James Carpenter with Joerg Schlaich. St Paul MN, 1991.

[39].Richard Rogers, Architecture, a Modern View. Thames and Hudson, 1990, p 16.

[40].Bridging the Gap. p 140.

[41].Charles Knevitt, "Arched Bridge Could Be Gateway to the Capitol." The London Times, 4 July, 1990.

[42]Turin Exhibition Hall, 1940 - Pier Luigi Nervi.

[43]Luigi Nervi, Structures. F. W. Dodge, 1956. pp 67, 80.

[44]"Engineers Rise to the Occasion", p 35.

[45]Bridging the Gap. Pages 162, 163.

[46]Bridging the Gap. Page 162.