8.1. The Dilemma of the Bridge Built in 1640

The first mentions of the bridge date back to the 15^th century. However, there are also mentions of the building of the bridge by Philip IV in the 1640s. Two possibilities, thus, come to mind:

1. The bridge was built in the 15^th century and then restored in the 1640s. The two sections of the bridge that we currently see date from both these years: one half is what remains of the 15^th century bridge, and the other was built in 1640.
2. There was a bridge built in the 15^th century at that location. That bridge was destroyed and a whole new bridge was built in 1640 on the same site. The new bridge was built completely from one design, and the observed differences between the north half and the south half are due to a restoration that had to have been done after 1640.

We believe that the second theory carries more weight than the first. The sources that mention the construction of the bridge in the 1640s don’t speak of restoration or remodelling, but of “construction.” Historian Pablo Alzola also writes that the “Garaicejo” Bridge was erected between the years of 1630 and 1640. Alzola does mention the restoration of other bridges during the same period, such as the Salamanca Bridge (36). On the other hand, Madoz mentions the existence of the coat of arms of a bishop who ruled Plasencia between 1766 and 1803; it can be deduced that the bridge was subjected to some important restoration work during that period, to justify the inclusion of an escutcheon.

Therefore, one part of the bridge that we can see today originated in the 1640s; the rest of the bridge is due to a restoration after 1640, possibly between 1766 and 1803.

8.2. Dionisio Sánchez’s Plan

Dionisio Sánchez’s plan (Figure 3) is the first graphic representation of the bridge that we have. This plan is part of a project for a road going down from and up to the bridge; therefore, the bridge that is represented therein already existed at that time.

Figure 3. Fragment of Sánchez’s Plan.

The plan must be considered very exact, as the letter accompanying it indicates that everything has been undertaken with “delicacy, clarity, intelligence and zeal”. Its legend explains each part of the road in detail, and includes a series of cross-section profiles of the road and the bridge itself.

The most interesting element of the plan is the non-existence of the ramp towards the middle of the bridge platform (Figure 4). However, the southern rampart was significantly longer and had two small access points to the riverbank. The legend on the plan itself indicated the existence of “exits on one and the other part (…) for free transit of the royal bridleway when they ford the river”. Regarding the width of this rampart, it mentions that the road leading to the bridge had a width of 5 toises, about 8.4 m.

Figure 4. Letter K represents access points. Letter J is the road leading to the bridge. Letter L represents the Royal Bridleway.

According to Sánchez, the width of the bridge was “13 feet in amplitude”, and proposed to widen it “to 15, so that carriages can come and go without getting in each other’s way”. Since a Castilian foot equals 28 cm, Sánchez suggested adding 56 cm to the width. This modification would have been done by opening the parapets.

If we compare cross section “21-22” contained in the Sánchez’s plan with the graphic scale of the plan itself, we can confirm the drawing’s high precision, since in fact, the width of the vault and the platform is 2.5 toises, a measurement equal to 15 feet, or 4.2 m (Figure 5, up). The current width of the platform, measured with modern topography, is 4.24 m; this datum proves that the amplification was undertaken, and also that Sánchez’s plan matches reality.

Figure 5. (Up) Comparison Between the Section of the Bridge Named “21-22” and the Graphic Scale Accompanying the Profiles. (Down) Graphic Measurements of Sánchez’s Plan.

Using the plan, we can also figure out the length of the platform. It is true that there is no scale on the plan, since the graphic scale used only refers to the cross-section profiles. In addition, there is no indication, anywhere, of the number of arches that make up the bridge. However, there are two elements whose measurements we know: the width of the platform and the width of the rampart. If we compare these two known measurements and the length of the bridge (Figure 5, down), we can deduce that the latter measurement is 93.66 m. We must highlight the consistency of all the dimensions in the plan, since the result, 93.66 m, was obtained comparing two different measurements. The current bridge, from the arch edge to arch edge, measures 111.76 m.

Thus, the bridge portrayed in Sánchez’s plan, from 1764, has at least four significant differences with the current bridge:

• It does not include any type of ramp in the centre.
• It includes a series of access points in the ramparts, which do not currently exist.
• The length of the bridge is 93.66 m, compared to the current 111.76 m.
• The junction with the road is through a right-handed curve. However, the remains of the road leading to the bridge on the south side trace a left-handed curve.

8.3. The Campomanes Datum

The Campomanes manuscript mentions the existence of 10 arches on the bridge in 1778. However, a document from 1753 and one from 1797 both state that there are only 9 arches. This inconsistency can have different explanations:

• A writing error by Campomanes himself, who could have made a mistake at some point when transcribing the copious notes he took during his journey.
• The existence of a span with scant clearing in a rampart. Campomanes could have interpreted this span as another arch, while other authors could have seen it as a spillway.
• The existence of a “changing” arch: an arch that was open at some time and was closed at a later date.
• The existence of different construction phases.
• The superposition of two of the previous options.

8.4. First Hypothesis on the Bridge’s Historical Evolution

Dionisio Sánchez’s plan contains geometric data on the structure that existed around 1764, and it also reflects the non-existence of a ramp in the centre. Using this information, we can formulate a first hypothesis explaining the historical evolution of the Jaraicejo Bridge.

The original bridge, built in 1640, was made up of a succession of similar arches to the two semi-circular arches on the right side (Figure 6.a). After 1764, but before Campomanes travelled there in 1778, there was a surge that ruined part of the bridge, leaving only the two right arches standing (Figure 6.b).

Figure 6. The Original Bridge, with Six Arches; (b) State of the Bridge after the Surge; (c) Current State of the Bridge.

In order to avoid future problems with the bridge, its reconstruction included a series of decisions that contributed to making it more stable and robust.

Thus, they decided to widen the span of arch 3, the one most exposed to surges. The new arch also needed to maintain the same rise, to guarantee the maintenance of the same gradient of the platform. This led to the decision to build a three-centred arch. If they had decided to build a semi-circular arch larger than the ruined one, the height of the span would also have increased, leading to the modification of the gradient.

At the same time, they decided to increase the number of arches to increase the hydraulic capacity. The amplification was done to the south half of the bridge, since the south rampart was noticeably long and allowed for reconversion into a set of arches (Figure 6.c).

But there was a problem with expanding the bridge to the south: as we’ve seen in Sánchez’s plan, this rampart had an access point to the Royal Bridleway that runs next to the bank of the Almonte River. Converting this rampart into a set of arches meant that this access point had to be placed elsewhere, and the decision was made to place this access to the bridleway on pier 3 of the bridge, which had to be rebuilt. This solution can be considered ingenious: not only was there a place to put a ramp, but this ramp would also have a structural function, serving as a resistant support for the bridge in the case of any future surge.

Finally, the ornamental elements that could be recovered from the collapsed bridge were used during the reconstruction. The niche and other details we find, and that are mentioned in the construction of the bridge by Philip IV, must have been located somewhere else. Perhaps the surge affected the niche or the escutcheons; that would explain the fact that the preserved remains of the niche are not symmetrical, and could even be part of a larger ensemble. It would also explain the significant colour differences that exist among the ashlars that comprise the escutcheon set, as if this set had been restored using original and adapted pieces.

In order to analyse the validity of this hypothesis, we have drawn the reconstruction of the original bridge, the collapsed bridge after the surge, and the re-built bridge (Figure 6). The drawing of the reconstruction has been created following these steps:

• The two north arches are measured, along with the two immediate piers.
• The hypothesis that the bridge originally had only one type of arch and pier is formulated.
• The hypothesis that the south face of the original pier 3 coincides with the south face of the current pier 3 is also formulated. This hypothesis considers that the foundations of the old pier 3 must have been used to rebuild the new one.
• We assume that pier 3 must have measured the same as pier 2.
• We assume that the original bridge was symmetrical.
• The measurements adopted are reflected in the attachment, and prolonging the gradient of the current bridge over the north side arches, we have drawed the bridge in its original state (Figure 6.a). Using this drawing, we can draw the moment at which the bridge was partially destroyed by the surge, as well as its reconstruction, which has remained to this day.

The possibility that the different historical phases of the bridge coincide with the hypothesis described above has several solid arguments in its favour. Firstly, the six-span bridge has a length of 93,35 m, making it very close to the 93.66 m on Sánchez’s plan. Additionally, it explains the appearance of a ramp in the middle of the bridge. Lastly, this sequence of events fits the totality of the information found in the historical sources, except for one, which is described below.

On the other hand, the colouring of the ashlars mentioned in the Visual Analysis section (Figure 2) coincides with the phase represented in Figure 6.b; the projecting ashlar in the intrados of the second pile, also mentioned, would coincide with the springer for the third semi-circular arch of the bridge described in Figure 6.a, located below the springer of the current three-centred arch; the same thing could be written about the break line already described on breakwater number two.

The main weak point of this theory lies precisely in that it does not fit the information contained in the Cadastre de Ensenada, which mentions the existence of 9 arches in 1753, 8 years before Sánchez’s plan.

Another weak point is that the south arches show greater quality of craftsmanship than the north arches, and in general, restorations tend to be of lower quality. The high aesthetic quality of the new arches demonstrates that there must have been sufficient funds to undertake the work. In this case, we can additionally ask ourselves: why weren’t all the new arches made with greater size? If the purpose was to improve the structure so it could withstand future surges, the logical course of action would have been to not only build more arches, but to make them more spacious than the existent arches.

However, it is convenient to remember that the information contained in the Cadastre de Ensenada does not come from the Marquis’ own observations, but from data collected by third parties. In this sense, these documents occasionally have significant errors; without going any further, we can mention that the measurement indicated by Madoz in 1847 for the bridge is 76 yards, or 64 meters in length, a wrong measurement.

8.5. Second Hypothesis on the Bridge’s Historical Evolution

The previous section is proof that there are two pieces of information that are difficult to fit together: the data from the 1764 plan, which define a bridge measuring 93.77 m, and the description of Ensenada in 1753, which mentions the existence of 9 arches. If we consider both data valid, we can formulate an alternate hypothesis. We will rule out the possibility of Sánchez reproducing the bridge erroneously, since the survey he performed was done with very precise instruments, as can be confirmed by the nearly exact match between the width of the bridge measured for this study and the width he drew.

This second hypothesis assumes that the bridge described by Ensenada, of 9 arches, is the same that Sánchez later reproduced. We rule out, then, the possibility that the bridge mentioned by Ensenada is different from the one drawn by Sánchez, since it would be exceedingly rare to have two reconstructions in such a short period of time: one between Ensenada and Sánchez and another between Sánchez and the creation of the ramp, which we know existed by 1797.

If we analyse the geometry of the existing arches and piers on the south side, we can see that the measurements are around 8.30 m for arches and 2.52 m for piers. A nine-vault bridge built using this type of arches would have a length of almost 95 m.

If we assume that the six arches of this type that currently exist date from that period, the original bridge must have looked similar to Figure 7, which presents a length of 94.75 m. However, there is a series of circumstances that contradict this possibility. In fact, the lowest-level area in the riverbed would have been occupied by the north rampart, and not by arches. Additionally, Sánchez described a very long south rampart and a very short north rampart. Thus, this configuration makes little sense.

Figure 7. Drawing of a possible 9-Arch Bridge, “South” Type Model.

Nevertheless, it could be that some of the current arches on the southern end were added later. The original bridge could have been the one described in Figure 8.a, made up of 9 vaults of the south model and a long southern rampart that included the access points to the Royal Bridleway.

Figure 8. Different Images of the Bridge Structure: (a) The Original Bridge; (b) the Four Arches that remained after the Surge; and (c) The Rebuilt Bridge.

A surge that took place before 1797 (date at which we have evidence of the existence of a ramp) destroyed the five arches located in the lowest part of the valley. The reconstruction that was undertaken consisted of substituting the five collapsed arches with three new arches with greater span and more robust piers. Additionally, another two arches were added on the southern end, imitating the model of the four remaining arches, and thus shortening the rampart on that side and eliminating the possibility of accessing the Bridleway from there. Just as we described in the previous hypothesis, the solution was to create the ramp attached to the theoretically weakest pier in the structure, seeking to reinforce it from a structural point of view.

The strongest argument for this possible historical evolution of the bridge is that it can support absolutely all of the known information regarding its geometry and number of arches.

Additionally, as we have mentioned before, restorations usually have worse craftsmanship than the original bridges. In this sense, the vaults on the north side were built with less quality than those on the south side, and there are even two types of arches, considering both shape and number of orders.

This could also explain the asymmetry of the niche that stands on pier 1, which would have originally been located elsewhere. It is possible that, during the restoration, they decided to reposition it on the recently built breakwater, adapting its width to that of the breakwater.