New Alcántara Bridge in Spain

ABSTRACT

From chronological, constructive and heritage conservation points of view the Roman bridge of Alcántara (Spain) is an exceptional bridge. Erected around 103 AD on the Tagus River, it is still in use today for road traffic. Recently, the construction of a new bridge 200 meters upstream from the old one, intended to relegate the old bridge to pedestrian use, has been promoted. The examination of the new project and its long administrative procedure, as well as the analysis of the characteristics of the Roman bridge and its surroundings, both from a territorial and social point of view, provide a foothold to assess the new bridge according to a broad conception of heritage conservation. The objective of this work is to underline the unique history of the conservation of this bridge and, while presenting proposed solution for the new bridge, to highlight the patrimonial conditions that have been taken into account. The conclusion is that the administrative procedure followed in order to choose the solution and the project for the new Alcántara bridge are not adequate to the characteristics of such an outstanding monument.

KEYWORDS:

• Roman Bridge of Alcántara
• historical structures
• steel arch bridges
• rehabilitation
• heritage

Introduction

The Roman bridge of Alcántara (Spain) is an exceptional bridge from a chronological, constructive and heritage conservation points of view. It is one of the most admired ancient European bridges, with unique construction characteristics, even among the Roman bridges preserved up to this day. The history of its conservation is also very particular. It has been the subject of different documented actions since the sixteenth century. Indeed, it is striking that most of them have taken into consideration its heritage dimension and have tried to preserve its original structure. During almost 500 years few constructions have motivated interventions and concerns of this type.

Today, the Roman bridge is still in use for road traffic. Recently, the Junta de Extremadura, the body in charge of this construction, has promoted and approved a new bridge 200 meters upstream the old one. The intention for this new bridge is to absorb the road traffic. In this way, the old bridge would be reserved only for pedestrian use, and it would be preserved as a monumental landmark.

On the one hand, the objective of this study is to contextualize this project among the succession of historical actions for the conservation of the Alcántara bridge. Based on that, the unique history of the conservation of this bridge can be highlighted. On the other hand, the solution given for the new bridge, including its heritage motivations, that is, the characteristics concerning conservation and dissemination of heritage will be presented. The administrative procedure followed in determining the conditions to be met by this project and its final choice will also be analyzed. The intention is to assess whether the adopted procedure has been the most appropriate for this type of actions.

Methodology

Methodological approaches typical to different disciplines were applied, first asking various but complementary questions. Bibliographic and documentary research on the history of the bridge brings provides an insight into the past of its preservation. Compilation of the restoration projects that have taken place since the sixteenth century has enabled the reconstruction of the history of its preservation. Starting with a broad conception of heritage conservation, the basis for the assessment of the new bridge is built on the examination of the current project and its long administrative procedure, as well as the analysis of the characteristics of the Roman bridge and its surroundings, both from a territorial and social points of view. Problems and solutions found in Spain and neighboring countries, when acting on historic bridges of high heritage significance such as the Roman bridge of Alcántara, were taken into consideration as well.

The Uniqueness of the Roman Bridge of Alcántara

The Roman bridge of Alcántara is a unique bridge. Since its erection on the Tagus River during the reign of the Emperor Trajan around 103 AD it has been in use almost uninterruptedly until today. Its constructive characteristics are exceptional; the bridge has a total length of approximately 195 m and a width of 8 m. Made of bossage granite ashlars, it is composed of six half-barrel vaults with spans of 13.90 + 22.53 + 27.50 + 28.8 + 23.50 + 13.50 m. The two central piers, from the bottom of the river to the ground level, reach to about 52 m (Durán 2004) (Figure 1). In situ, there are historical inscriptions on its foundation by Trajano, another one with municipalities that financed it and, a last one, in a temple located in its left exit, with the name of Cayo Julio Lácer, its presumed author or person in charge (Figure 2).

Figure 1. Charles Clifford, “Alcántara Bridge Seen Downstream,” photography, 1859. The arch rebuilt between 1856 and 1859 is the second one from the left. Source: BNE, Spain.

Figure 2. Charles Clifford, “Triumphal Arch of the Alcantara Bridge,” photography, 1859. In the background, the temple erected at the exit of the bridge, on the left bank of the Tagus River. Source: BNE, Spain.

This historical, constructive and epigraphic uniqueness has established an extraordinary fame, also been very notable over time. Despite being located in a region that since the Middle Ages has been far from the main routes and large urban centers, the testimonies of admiration for the Alcántara bridge have followed one after another since the seminal testimonies of twelfth century Andalusian cartographers such as Al-Idrisi. Travelers, humanists, chroniclers, writers, architects and engineers have created a dense literature on this bridge. So early as in the seventeenth century, Jacinto Arias de Quintadueñas published a book collecting a good number of these references. It was cited in the classic works of Nicolas Bergier (1622) or Bernard de Montfaucon (1719–1724). Later scholars of the history of bridges (Seinman and Watson 1957) and, of course, the modern scholars of Romans themselves in their due time, were repeatedly referring to and analyzing this construction (Durán 2004, 264–272; Galliazzo 1994, II, 353–358). In Spain it has acquired a special significance among civil engineers. Recurrently, authorities in this professional sector, such as the engineer Carlos Fernández Casado (1905–1988), in addition a notable scholar of Roman bridges, affirmed that no one should build bridges, “without having passed through Alcántara” (Fernández Casado 2008, 100). Another renown engineer, José Antonio Fernández Ordóñez (1905–1988), who promoted in Europe the recognition of the civil engineering heritage value, considered it as a model for engineers due to its ability to overcome the limitations of its materials (Fernández Ordóñez 1990). In Spain, the mobilization of a part of this collective against those who want to erect a new bridge next to the Roman one, is indicative of its emblematic character. Its name, derived from the Arabic Al-Qantarat, The Bridge, seems fitting.

The Restorations of the Alcántara Bridge

This deep-rooted admiration for the Alcántara Bridge has conditioned corresponding subsequent interventions. The exceptionality of the bridge has meant that when acting on its structure, its historical character has been taken into account and that there was a desire to respect its constructive and formal characteristics. As presented in this study, this interest dates from the sixteenth century, which is something unique in the history of heritage conservation and restoration. In the first decades of that century, the first arch on the right bank was damaged, i.e., several stones were missing in its vault and some beams had been placed to allow the passage. Between 1532 and 1543 approximately, a series of works of almost 14 meters of span were carried out on this arch. Those in charge underlined the difficulty of carving, transporting and placing ashlars considering the dimensions of the Roman bridge. However, this was undertaken in this manner, as the stated objective was to “close the arch in the old-fashioned way” (National Historical Archive, Military Orders 31458). Contemporaries praised that the new construction was “similar to the old work,” indistinguishable except for the greater whiteness of the stone (Martín 2010, 91). Today, it is impossible to detect these interventions carried out during the Renaissance (Pizzo 2016, 3).

Between the seventeenth and nineteenth centuries, the proximity of this bridge to Portugal (currently just over ten kilometers away) made it suffer the ravages of various wars. The repair actions were based on the attempt to preserve the characteristics of the Roman bridge. In 1648, during the so-called Restoration War, which set the Spanish monarchy against the kingdom of Portugal, the second arch on the right bank was mined. The explosion caused the loss of part of the arch and a crack in the second pillar. These damages that occurred more than a century ago, as well as the displacement of the fourth pillar, submerged under water except for periods of extreme drought are shown on a model from 1772 (Figure 3). It was precisely this model that was made within the framework of a repair project that began a few years earlier. It is noteworthy that in the documentation related to this project, those in charge stressed that the bridge had to be repaired due to its military and communication uses, but above all because of its historical importance. Therefore, they decided to use the same stone, carve it with the same bossage as the original one and arrange it in the same double thread system (Navascués and Utande 2017). In fact, in a previous project, dated in 1751 but not carried out, the resort to the Roman quarries and remake of the old bossage in the new ashlars were also advocated (Cruz 1989).

Figure 3. “Model of the Alcántara Bridge” by José García Galiano, 1772. Source: National Historical Archive (Madrid), inv. Objects-90.

Between 1775 and 1778 the arch was restored and, according to the contemporary evidence, as the one provided by the prestigious traveler Antonio Ponz (Crespo 2017, I, 103–104), this new work was undistinguishable from the Roman construction. The triumphal arch over the third pillar was also preserved, although it had been noted that it compromised the stability of the bridge. Therefore, the historical and patrimonial motivations for this action seem clear. However, the sinkhole in the second pillar on the right bank, the existence of which was known from divers, was not intervened. Towards the end of the 18th and in the first years of the nineteenth century, the Real Academia de Bellas Artes de San Fernando in Madrid, the main artistic institution in the country, mobilized prestigious architects, like the academics Pedro Arnal or Diego de Ochoa, to try to fix this pillar. The primary reason given by the Academy to repair the Alcántara bridge was its historical interest (Crespo 2017, I, 72–75). In the end, the pillar could not be repaired, but a more obvious problem was about to affect the bridge.

In 1809, during the War of Independence, which confronted the Spanish-English troops with Napoleon's army in the Iberian Peninsula, the second arch on the right bank of the Alcántara Bridge was exploded for military reasons. On this occasion, the arch which had been restored only thirty years ago, was completely destroyed. Rehabilitation projects piled up in the decades that followed. In the first half of the nineteenth century, given the poor state of Spanish government finance, cheaper solutions than redoing the arch with ashlar masonry, such as a brick double arcade, a wooden passage and even an iron footbridge were proposed. However, these solutions were said to be temporary, pending the sufficient budget. It was reiterated that the definitive repair had to be respectful for a bridge that was “one of the most celebrated monuments of Antiquity and of the noble arts in Spain” (Crespo 2017, I, 139). The expected moment came in the middle of the nineteenth century.

In 1856 the restoration works of the Alcántara bridge began, they were directed by the civil engineer Alejandro Milan and completed in 1860. In a time when rehabilitation theories in Europe and Spain advocated restoration in style, Millán's project attempted to remake the collapsed arch “without changing the shape and exterior construction of the bridge.” Moreover, Millán's work was comprehensive, i.e., the other arches and pillars, the pavement, the parapets or the annexed temple were also restored. With the advice of the architect Agustín Felipe Peiró, the triumphal arch of the bridge was rebuilt according to its original layout (or at least, the one that has been known since graphic information about it has been available). Although the spirit of Millán's intervention was clear, variations with respect to the primitive construction, such as the starting point of the vault, which is not situated at the upper layer of the strains as originally, but at a new, higher cornice, are detected. Likewise, the reformed buttresses form a single body with the tympana, as compared to abutted Roman ones. The primitive slope was rectified as well and that corrected the original ridged profile (Crespo 2017, II, 94).

The extensive photographic repertoire that Charles Clifford made just after the restoration of Millán, shows the intention of integrating the new work with the old one and of recreating the presumed original appearance of the Roman bridge (Figure 1). Hence, its unified appearance was promoted, without any elements distorting its lines. It is revealing, that in order to control the passage, Millán eliminated numerous constructions, including some historical ones, that existed at the entrance and exit of the bridge. In their place he drew two wide esplanades, supported by ashlar slopes, which not only served to improve the accesses but also enabled monumental observatories. Afterwards, the bridge appeared to be newly built, resembling an abstract prototype, devoid of all that distorted its simple and majestic profile. This aspectwas highlighted in the photographs of Clifford and in those made shortly after by Jean Laurent, the other great name in Spanish photography of the time.

These photographs reveal the remarkable impact that the restoration of the Alcántara Bridge had in contemporary Spain. Throughout the press and other media, the regional and central authorities, even the civil engineers presented this works as a managerial success, what is more, as a success of a country that since the beginning of the century was immersed in a serious crisis and thus, in need of accomplishment.

The rich documentation preserved from the Millán restoration reveals the conceptual assumptions guiding his project and the complex administrative process that was followed (Crespo 2017, II, 69–98). Additionally, it also provides interesting references on the construction proceedings, especially on the movement, the placement of ashlars in the arch and the configuration of the non-continuous shoring system, since it had to reach above the water level (Figure 4). A hanging walkway with its suspension elements helped the work of material elevation. The auxiliary elements used are also of interest, i.e., a locomobile crane to support the overhanging scaffold adopted in the repair of the intrados of the vaults or a slewing crane for loading the ashlars in the wagons (Figure 5).

Figure 4. Alejandro Millán, “Alcántara Bridge. Formwork used for the reconstruction of its arch,” h. 1857. Source: San Benito de Alcántara Foundation.

Figure 5. Alejandro Millán, “Alcántara Bridge. Locomobile crane for supporting the overhanging scaffold used to repair the intrados of the vaults; slewing crane for ashlars loading in the wagons,” h. 1857. Source: San Benito de Alcántara Foundation.

The subsequent works on the Alcántara bridge have been less important, but not irrelevant. In 1946 and 1950 the drains were intervened; other minor works, on pavement and parapets, were carried out as well. In 1960–1969, on the occasion of the construction by José María de Oriol, the dam was left dry in the rising section of the Tagus River some 900 meters upstream from the Roman bridge. At the base of the fourth pillar, a slope formed with large blocks of rough stones was found; it was placed in the Millán’s intervention. When they were removed with bulldozers, the pillar was found partially exposed. The engineers of Hidroeléctrica Española, the company in charge of these works decided to clean the sediments from the caverns that appeared at the base and concrete them, without communicating this fact to any administration or cultural institution (Fernández Casado 2008, 107). In the last decades, the Roman bridge has not deserved any intervention. Therefore, the new bridge that is now planned in its surroundings is surely the most relevant action in the last 150 years.

Alcantara and Its Roman Bridge Today

Nowadays, the Roman bridge is still in use, it is located just 400 meters from the historic town of Alcántara, in Extremadura. This autonomous community has one of the lowest levels of gross domestic product per capita in Spain and a low demographic density. These economic and demographic characteristics are even more accentuated in the Tajo-Salor Association of municipalities, to which Alcántara belongs. In 2010, the Tajo-Salor region had 28,500 inhabitants, with a density of 13 inhabitants / km² (López and Pinilla 2013, 37). In 2020, Alcántara registers 1,411 inhabitants, with very little natural growth and a regressive population pyramid (INE 2020). Work market in this area is limited and it is mainly focused on the agricultural sector. It is a clear example of what, in recent years, has been called “emptied (rural) Spain.”

Despite the proximity of Alcántara to the Portuguese border (11 km) (Figure 6), vehicle traffic is scarce, since it is not a priority corridor in Spain-Portugal communication roads. According to the corresponding nearby measurement station, its average daily traffic (ADT) intensity for heavy vehicles is 35 vehicles / day (Proyecto 2019).

Figure 6. Situation of the Roman Bridge of Alcántara. Source: https://www.turismocaceres.org/es/turismo-cultural/puente-romano-de-alcantara.

Like other areas of emptied (rural) Spain, this lack of economic activity and demographic muscle contrasts with its heritage and natural wealth. Alcantara has a remarkable architectural heritage. In 2015, an administrative proceeding was opened for its declaration as Asset of Cultural Interest, the highest protection existing in Spain in the category of Historic Sites (BOE 2015). However, recently in Extremadura, its Department of Culture has allowed this file to expire (DOE 2020; García 2015).

The bridge is located one kilometer from the urban center of Alcántara, but it is not included in the Protected Area of “Tajo-Tejo International Cross-border Biosphere Reserve” (Figure 7). It is remarkably close, although also not included in the International Tagus (River) Natural Park and several places in the “Natura 2000 Network” (Environmental Impact Report of the Department from May 28, 2019).

Figure 7. Roman bridge of Alcántara in its current environment. Source: Own elaboration.

Despite this nature and landscape richness, there is no doubt that the best known, and most emblematic landmark of the region is the bridge itself. Despite this nature and landscape richness, there is no doubt that the best known, and most emblematic landmark of the region is the bridge itself. The local associations of Alcántara, as they are aware that it is the main cultural and touristic of region asset, have been organizing different activities in order to denounce the lack of interventions on the old bridge, taking it for a sign of the abandonment suffered by the municipality and the region. Currently, the bridge is included, as an element at risk, in the red list of the Heritage of Hispania Nostra (Hispania Nostra 2021). The stated intention of the new bridge project realization is thought to reverse this situation.

A New Bridge in Alcántara

The Roman Bridge of Alcántara is part of the EX-117 roadway. As an regional highway, the bridge is the responsibility of the government of this territory, specifically the Department of Mobility, Transport and Housing of the Junta de Extremadura. For this reason, the bodies of the Junta have independently proposed and formulated the project to erect a new bridge over the Tagus River, situated 200 meters from the Roman one.

According to the document for public information prepared by the aforementioned Department, the proposal of a new bridge construction began in 2009 (Proyecto 2019). On this date, the General Directorate of Cultural Heritage of the Junta de Extremadura, the body in charge of managing and protecting the heritage of this region, issued a report. Thereby, it pointed out the need to restore the Roman bridge and recommended building a new one to channel all road traffic, while leaving the old one for pedestrian use. In 2011 another report was drawn up; it was completed in 2012 with the one carried out by the Department of Mobility, Transport and Housing. These reports were a starting point for a study of solutions to define the alternative layouts for a new bridge (Figure 8). Once its location was determined, a public tender was organized, resolved by the Department's staff in 2018. The project presented by the company Estudio AIA, Arquitectos Ingenieros Asociados and INGEX Estudio Técnico was the winner (DOE 2018). Currently, the construction competition for carrying out the winning project has been published.

Figure 8. Aerial view of the alternatives of the new bridge layouts and positions (Alternative 1). Source: Junta de Extremadura.

The objective established for the new bridge is the protection of the Roman one by freeing it from the road traffic. In the Project for the layout of the works of the new bridge, the pathologies of the Roman bridge are collected, among them sunken paving, insufficient drainage, open joints, dampness, vegetation and some deteriorated joints between ashlars (Proyecto 2019). Some structural engineers point out that these are superficial damages given the low level of traffic and considering that the bridge presents only functional and not structural problems (Navascués and Goicolea 2021). It should be noted that non-destructive, auscultation monitoring techniques with the application of ICT Technologies (electrical, electromagnetic, ultrasonic or thermographic) have not been used. They could allow an adequate assessment of the state of the materials and of the bridge as a whole. Besides, it would have been desirable to include recognized specialists in this kind of unique structures, i.e., ancient stone bridges in elaboration of these reports.

It is well known that the construction of new passageways to protect the old ones of heritage interest is a common procedure. Between the late 19th and early twentieth century in Spain, interventions of this type were already documented. In the second half of the nineteenth century, the growth of the city of Salamanca induced the idea of extending the Roman bridge over the Tormes river using overhanging iron platforms; at that time, it was a common solution throughout Europe (Figure 9). However, in 1891 the Salamanca authorities proposed to build a new bridge upstream to respect a “distant historical monument” in the best possible way (Crespo 2017, II, 135). The new metal bridge was inaugurated in 1913.

Figure 9. Gumersindo Channels, Detail of the project of widening with the use of cantilevers, Roman bridge of Salamanca, 1891. Source: General Administration Archive (Alcalá de Henares) sign. 04 24/3442.

Although throughout the twentieth century there were other examples, it has not been until recent decades that this type of ventures has multiplied in Spain. Just to name a few, not too far from Alcántara, the Roman bridge of Mérida and the medieval one of Zamora have been pedestrianized, diverting their traffic to new passageways. The Mérida’s case is interesting because this is the first modern bridge (inaugurated in 1960 according to a project by Fernández Casado) whose design is in visual harmony with the roman design. However, the most recent bridge from 1991, that was erected downstream was subject to no debate. Undeniably, there were also some disputed instances due to their controversial designs, such as in case of the new Orense or Millennium Bridge (2001) (Figure 10), some 400 meters downstream only from the emblematic medieval bridge. These types of debates were common in other historic European cities as London, Paris, or Budapest with its many historic bridges (Cerro-Santamaría 2013). However, it is a long-standing tradition especially in urban bridges, to opt for more respectful solutions that consider the neighborhood with historical bridges or their insertion into a monumental complex. At the beginning of the twentieth century for instance, when there was a need of a new passageway that would avoid traffic over the medieval bridge of Alcántara, in Toledo, an option of a bridge that would pass as “unnoticed” as possible was taken. Hence, after a long process and notable debate, a simple mass concrete bridge with a single arch and a masonry surface taken from the banks of the Tagus River was chosen (Crespo 2017).

Figure 10. New bridge in Orense, with the medieval bridge in the background. Source: https://www.turismodeourense.gal/recurso/puente-del-milenio/.

In case of the Alcántara new bridge, the intention was that its structural solution should not steal the spotlight from the Roman bridge and that both constructions ought to be in harmony with each other and with the natural environment. This concern is due to the fact that the new bridge will be erected merely 200 meters away from the old monument. They are in the same valley of the Tagus River and with direct visual communication, in an environment without buildings, vegetation or natural or geographical features that hide the view of the new bridge from the Roman one. Despite this proximity and direct visual connection, the Department of Mobility, Transport and Housing determined in 2015 that this location 200 meters away was the most suitable one (Proyecto 2019). In the study of alternatives there were important conditioning factors. Downstream from the Roman bridge there is the International Natural Park of Tajo (River) and upstream, about 900 meters away, there is the Jose Maria de Oriol dam, with a large water reservoir and a capacity of 3160 hm³ (Figure 11).

Figure 11. Photomontage of another, non-selected solution of the contest with view of the dam in the background. Source: Own elaboration.

Given this proximity, the Department determined that the structural solution should be “discreet,” opting for a simple bridge typology, without structural elements on the ground, predetermining its elevation so that it does not stand out above the Roman construction. Ramón Alfonso Sánchez de León, the engineer responsible for the project, stressed that the main objective of the project was the integration of the new bridge with the historic one and with the natural environment. For this reason, he opted for the arched solution, widely used by Romans on their bridges. The designer has drawn an arch that crosses the river without intermediate supports (with 180 meters of span and five accompanying compartments) seeking to interfere as little as possible in the landscape. On this arch, he has arranged the pillars on which the panels rest. The material chosen is self-oxidizing Corten steel due to its chromatic similarity with the environment (a reddish slate by virtue of its iron composition) and on behalf of its associated visual lightness (Figure 12). Thus, according to his words, the use of concrete is avoided so as not to load the landscape even more, as it was already impacted by the José Maria Oriol concrete dam, with 223 m of maximum height (Sanchez de León 2020).

Figure 12. Project solution for the bridge elevation. Source: Project (2019).

It is interesting to note that the Department wanted to have a “reasonable distance” between the two bridges. The purpose of this proximity is to establish a pedestrian crossing between them and to place a pedestrian walkway that allows contemplation of the old construction from the new one. In the winning project by Sánchez de León, the pedestrian walkway, 3.50 meters wide, is placed downstream, parallel to the road but separated from it by 1.40 meters. It is supported by the transverse ribs of the bridge section (Figure 13). The enabled visual perspectives are exceptional.

Figure 13. Project solution for the cross section of the bridge. Source: Project (2019).

It seems that the idea of converting the new bridge into a belvedere of the Roman one was one of the reasons why an alternative located further, above 400 meters away from the millenary structure was discarded. In rejecting this alternative, the decision-makers have also indicated the greater proximity to the dam (Proyecto 2019). However, the annex of allegations of the Hydroelectric Company only focused on the need of foundations protection against erosion, which is common in these cases. Likewise, it warns of the possible necessity of introducing traffic cuts during floods when de-watering would be necessary (Alegaciones 2020). The truth is that in the public documentation of Project on the layout of the new bridge over the Tagus River, no reason is given to ignore the alternative which would mean a greater distance from the Roman bridge. This is not a trivial aspect. In addition, this further alternative could also involve the parking plot for visitors, about 500 m away from the Roman bridge. It is true that the pedestrian walkway next to the new bridge would not make so much sense these 400 meters away, but it is doubtful if the old bridge needs additional perspectives, as its location and its current environment provide enough views to understand and enjoy its structure and significance. Obtaining the perspective from the new footbridge will force the pedestrian to leave quiet views in a naturalized environment and to take a walk parallel to a road with traffic (Figure 14).

Figure 14. Infographic of the views of the Roman bridge from the pedestrian walkway of the new proposed bridge. Source: Project (2019).

If the very need to build a new bridge has been questioned, its location should also be a food for thought. The landscape level impact of the proposed new construction is unquestionable. The environmental report did not mention the landscape (Environmental Impact Report of the Department from May 28, 2019), but the surroundings of the Roman bridge are made up of rocky outcroppings with the presence of Mediterranean scrub that does not contain accidents or natural elements that can hide modern construction. Although an arch is used as a structural solution, 180 meters of its span with 210 meters of the first section (410 m in total), introduce another visual scale, completely alien to the one that the old bridge had for millennia within its surroundings (Figure 15). The construction of the José Maria Oriol dam had a significant impact on the landscape, but it was erected in other times and almost a kilometer away. In any case, except for this concrete wall, in the immediate surroundings of the bridge there are practically no modern buildings in elevation.

Figure 15. Relation between the Roman bridge and the proposed new bridge (Project infographic). Source: Project (2019).

The acknowledgement of the landscape as an outstanding heritage element was already suggested in the Athens Charter (1931). In the following decades and after relevant contributions, this value has been consolidated through the European Landscape Convention (2000). This agreement has led to a change in the way of conceiving landscape values in Europe (Fry et al. 2009) since it promotes an integrated approach where the landscape is understood as “the territory perceived by the population, whose character is the result of the action and interaction of natural and human factors.”

Spain ratified this agreement, which entered into force in 2008 (BOE 2008). In fact, the Law of Historical and Cultural Heritage of Extremadura, approved in 1999 and in force in this Spanish Autonomous Community, recognizes the obligation to define the necessary environment to protect real estates of cultural interest (art. 8.1.b). There is a note that “the volume, typology, morphology or chromaticism of the interventions in the surroundings of the monuments cannot alter the architectural and landscape character of the area” (art. 38.2). Moreover, the aforementioned law establishes a protective environment of at least 100 meters for architectural elements and 200 for those of an archaeological nature (art. 39.3). It does not seem reasonable to limit this question to a simple arithmetic figure. When reflecting on the spirit of the agreement, it would rather imply the treatment of the impacts on the landscape through the integration of different disciplinary traditions, physical as well as subjective and cultural ones (Mata Olmo 2008).

In this sense, the landscape impacted by the proposed project does not consist only of a certain natural environment, as a matter of fact, it should consider the dialogue and relationship that said environment has had with the Roman bridge for millennia, the case being here that the construction and the surroundings become one and the landscape is recognized and apprehended by the observer (Besse 2010; Ferrer and Mata Olmo 2020) and thus the place is part of collective imagination (Lopez 1986).

The 1924 declaration of the Alcántara bridge as a National Monument means that it does not have a delimited protected environment. However, in the administrative record that started in 2015 and was intended for the declaration of the town of Alcántara as a historic site, a protection environment of 100 meters was established for the Roman bridge (BOE 2015). Based on this, in 2015 the Provincial Commission of Historical Heritage of Cáceres (capital city of the Spanish province where Alcántara is located) decided not to issue any report on the proposal to erect a new bridge scarce 200 meters away from the old one. The Commission defined itself as “not being competent in the matter of this report issuance” (Project 2019, 5). The Department of Mobility, Transportation and Housing has not requested any other reports. It should be noted that the historical site declaration file, establishing 100 meters of distance, expired in 2020 (DOE 2020).

Even if the analysis of the landscape and cultural impact is insufficient, this rather decisive intervention in the surroundings of the Roman bridge is to be conclusively carried out. In fact, this lack of report for the new bridge 200 meters away is based on a file that has finally expired and that established a minimum legal distance. Whether determining the minimum distance in a monument and in an environment as particular as that of the Alcántara bridge makes sense is another relevant question. Indeed, there are reasons for argumentation line that the landscape, monumental and historical conditions of the Roman bridge of Alcántara and its surroundings are very special, and thus should have been taken into account, despite the passive tradition of the Spanish cultural administration (Amores Carredano 2005).

Even if at specific moments technicians from the General Directorate of Cultural Heritage of the Department of Education and Culture have participated in the development of this administrative file, in a project of this characteristics, which affects such a unique monument, a more in-depth analysis of its patrimonial and landscape impact, as well as a greater involvement of cultural institutions or organizations should be required. Actually, in Spain there are strongly rooted consultative institutions with extensive experience in the heritage field, both at the regional and national level.

It should be noted that in the entire budget earmarked to this work no item is allocated to the restoration of the Roman bridge. The total budget for the new bridge is 17,419,820 euro. It is a budget that is high for the Extremadura Department of Mobility, whose entire region infrastructure and transport budget in 2021 is 80 million euro. It is therefore surprising that no part of it is assigned to the preservation of a structure that according to the same reports, that have motivated this intervention is in a compromised situation. However, if this restoration were to be considered in the future, more mature solutions than those carried out in the intervention on the neighboring Segura bridge would be recommended by the authors. In 2007, Segura bridge, other Roman bridge over the Tagus River, about 15 km from Alcántara and also under the jurisdiction of the Junta de Extremadura, was subject to controversial works. They consisted of grouting with cement the joints of the blocks, which were bounded together in stone on stone originally, and reinforced the foundations with concrete clearly visible (Durán 2010).

A comprehensive protection plan for the Roman bridge and its surroundings has not been proposed. There are outstanding archaeological remains of old tracks that reveal the importance of the bridge in the region's road network, and that explains both the construction of the bridge, its repairs throughout history and the communications network of which it was part. There are also sections of the towpaths that can be linked to different projects to make the Tagus River navigable. However, the new bridge project defines only generically, without specifying content, the extension or a budget for a future interpretation center located in the car park for visitors’ reception. In fact, in the winning project for the new bridge, the characteristics of the pedestrian circuit thought to connect it with the Roman construction are very poorly detailed.

Probably, this is in part so, because the project focuses on the structural aspects, on the formal and structural definition of the new bridge. On the contrary, the Roman bridge and its corresponding heritage play a merely passive role. The prominence claimed by the new bridge is even more striking when planning to place an “information landmark” consisting of a full-scale section of the arch (Figure 16) supported on a concrete pedestal, in the landing area of the footbridge. What is more, an information point explaining the Roman bridge, the new one and the José Maria Oriol dam (Fundación Juanelo Turriano 2021), in a kind of open-air engineering museum is planned to be settled in that place. The opportunity to claim so much attention to the new bridge in front of a thousand-year-old and emblematic construction such as the Roman bridge of Alcántara may be debatable.

Figure 16. Cross section of the information landmark in the bridge solution project. Source: Project (2019).

Part of the most problematic aspects of the new bridge in Alcántara may be assigned to the administrative process that was followed. Some arguable features in the procedure for alternatives determination, conditions definition, bidding, and resolution of the tender are detected. It should be discussed whether they are the most appropriate ones when tackling a project of this type, which actually affects one of the most unique bridges in the world. The rules of this public tender were drawn, without any external support or collaboration, by the Department of Mobility of the Junta de Extremadura. Much of it was a copy taken from other competitions for roads in the region, that is, without including the specific challenges of this case. The choice of alternatives and the winning contest were also determined by the limited Department staffing, which despite high professionalism, it is posible because the administration is local, they have not enought experience in projects of this type.

It should be noted that this is the usual procedure in the Spanish administration when acting on the road network and, therefore, also in processes that affect historic bridges. However, some better options could have been considered. In the architectural field, for example, it is more common hold previous contests of ideas that help handling a greater range of possibilities and alternatives. External advice when setting the rules for the contest or the election of a commission of experts in the competition selection board should not be considered (Arezzo 2021). In other neighboring countries, international competitions in this type of projects are also more common. For example, in early 2021 in the municipality of Arezzo an international competition was organized in order to erect an alternative passage to the medieval Buriano bridge. In this case, the modern passageway is also pedestrian, connected to the old one, but at a distance of more than 800 meters and thanks to the orography and the type of vegetation in the area, with a much less direct visual communication (Figure 17).

Figure 17. Map showing the location of the planned provisional bridge (number 2) and the new final bridge (number 3). Source: https://www.concorsiawn.it/ponte-buriano/home.

The participation of external and independent heritage professionals would also be recommended. The same is true of local associations. Different associations in Alcántara have been demanding more attention to the area and its bridge for some time already, organizing different activities that have involved the mobilization of society. Despite this, they have been ignored throughout the process. The inclusion of local institutions and communities, which will ultimately live with the heritage on a daily basis, is an objective that must be taken into account. The fact that a project of this size, cost and impact can be approved without considering the doubts of a notable part of the scientific, professional and local community does not seem appropriate.

Along these lines, it is also necessary to highlight that public debate has been lacking. There has there been no discussion neither in press nor in academic circles, despite the fact that the process, as already said, began in 2009. Only recently, with the project already approved and budgeted, it has been discussed in forums and critical publications have appeared (Navascués and Goicolea 2021). It can be attributed not only to the Junta de Extremadura, which has not promoted this dialogue, but also to civil and academic societies, as they have not demanded or undertaken this debate on their own. Therefore, the ways to explore in order to ensure a more appropriate procedure are diverse. On the one hand, there is room for greater awareness of the heritage in the public administration, which in Spain is responsible for a large part of historic bridges. In fact, there are alternatives to the usual administrative procedures for the approval of public works affecting a heritage asset. From certain sectors of civil engineering and the heritage field, there is a promoted interest in the approval of a national plan for the civil engineering heritage, coordinated by the State administration and with the active participation of regional administrations (Foro 2019). This plan would underline the importance of this kind of cultural legacy, especially rich in Spain, and the different ways of managing it. It seems urgent to act on this type of heritage, just as it was already done on others within national heritage plans. They began in 1987 with Cathedrals (1990), followed by industrial heritage (2001), or some more recent ones, such as that of defensive architecture (2012) or education and heritage (2013) (Ministerio de Cultura y Deportes 2021). Having both national and international external advisers could be an effective framework for reflection on objectives, methodologies and procedures. This is a possible way but not the only one. The orchestration of a civil society that is more informed and more sensitive to the management of the heritage elements included in the sustainable development of a territory, is the main challenge and the best guarantee that the actions correspond to society aspirations.

Conclusions

This study proves that some historical repair projects carried out for the Roman bridge of Alcántara were exceptional in their due time. However, the one currently proposed is not only not unique but also presents some problems. Part of the doubts could be attributed to the administrative procedure followed in order to choose the solution and the project proposal for the new Alcántara bridge. It is striking that for a construction venture in such a particular environment, affecting a monument as prominent as the Roman bridge of Alcántara, studies regarding the state of conservation of the bridge, the visual impact of the new bridge on the old one and its surroundings have not been carried out. These same concerns apply for the participation and advice of certain institutions and sectors of the civil society that have not been taken into account.

Additional information

Funding

This manuscript has been carried out as part of the Ministry of Science and Innovation's (I+D) Research Project “Water and Lights. Spanish treatises on hydraulic architecture in the Illustration” (PID2020-115477GB-I00).