The aqueduct from Stymphalos

Basic bibliography: W. Biers 1978; Lolos 1997

Fig. 3.125 Aqueduct from Stymphalos. Mortared rubble wall of the bridge at the Skoteini valley (by courtesy of G. Rombakis)

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Alepotrypes and had walls 1.70 m thick with six but‐

tresses 0.9 m thick 7 m apart. Inspection shafts and manholes¹³³were rectangular in plan and measured 0.72x0.65 m.

Description and remarks on building tecniques The aqueduct was built with mortared rubble (fig.

3.125). The channel was waterproofed with 3 cm crushed‐brick mortar; it was 1.12 wide and 1.6 high and was covered with a vault made of radially laid stones (fig. 3.126). A formwork with six wooden boards supported the vault construction¹³⁴. The vault had a span of 1.30‐1.40 m. To avoid leakage of water into the rock, the channels were built with masonry also in the tunnels. The construction phases of these channels can be reconstructed as follows: the channel was dug into the rock up to a height of 2.50 m in order to allow the construction of the masonry; the floor was built first, reducing the height to 2 m, enough for the masons to stand when building the specus. The centering was laid on the top of the walls on a recess and then the stones were laid on the centering radially. Since there are sectors of the vault where the stones were laid not radially¹³⁵presumably the builders could not guar‐

antee the radial positioning of the stones, especially when placing stones at the far end of the centering.

A similar problem was faced in the construction of the specusin Asirmato of Patras (see §3.7.2).

The arcades were built in a similar fashion, with stones placed radially. They were generally 2.2‐2.4 m wide, though smaller (0.8 m) and wider (3.40 m) spans were also used. The aqueduct can be com‐

pared to the Argos one (see § 3.1.5) built in the same region and period. At a certain point they pass close one to another. However, the two aqueducts, both remarkable for their length (Corinth: 85 km; Argos:

33 km), were different, especially if the bridges are compared. The most noticeable difference is that the walls of the Argos aqueduct were faced with bricks and the arcades were made of solid‐brick arches, while the Corinth aqueduct was exclusively built with local stones. This difference is even more strik‐

ing if the Corinth aqueduct is compared to other contemporary aqueducts of similar importance, as the Patras and Nicopolis ones, both using bricks for the wall facing and the arcades. The reason for this could be economic constraints, which almost cer‐

tainly influenced the Corinth aqueduct construction, because of its length. However material quarried lo‐

Fig. 3.126 The specusof the aqueduct of Corinth at Skoteini (from Lolos 1997, fig. 2

Fig. 3.127 Corinth Aqueduct. Ashlar wall of the bridge at the Skoteini valley (by courtesy of G. Rombakis)

cally, along the route of the aqueduct, are docu‐

mented also for the other aqueducts, where the core of the walls was made with local limestone. The difference is thus not in the material used but in the building technique: the Corinth aqueduct was built with mortared rubble, the other aqueducts were built with concrete, that is to say with horizontal layers of stones, laid layer by layer, tamped and eventually stiffened with bonding courses of bricks.

Moreover the brick arches in the Argos, Patras and Nicopolis aqueducts were made of bricks laid radi‐

ally, while the Corinth aqueduct arches were made with stones splinters placed radially, being thus of significantly lower quality.

A comparison between the bridges of these aque‐

ducts reveals that all were affected by collapsing, possibly because of the flow of the rivers, but the Corinth aqueduct bridges seem to have been dam‐

aged to a higher degree due to building technique.

The Stroggylo and Belanidia bridges, which are bet‐

ter preserved, are unlikely to belong to the original construction and must be considered rebuilt. Also

the Skoteini valley bridge, which at present is in ru‐

ined condition, had to be repaired, as documented by the ashlar blocks placed on the mountain side of the rubble‐masonry bridge (fig. 3.127).

Description of the Stroggylo bridge

GPS coordinates: 37°46’25.91”N ‐ 2 22°40’32.13”E The bridge is 42.50 m long and 11.20 high¹³⁶(fig.

3.128). It is the best preserved Roman bridge in the Peloponnese. It has two tiers of arcades, with one arch on the lower and six arches on the second tier (fig. 3.129). As suggested by S. Alcock¹³⁷this bridge could be a reconstruction. An analysis of the build‐

ing techniques confirms that the construction is not the original Hadrianic bridge, though it is not pos‐

sible to date it precisely.

The lower arch was made in limestone voussoirs, with a curved extrados. The dimension of the vous‐

soirs is regular and joints alternate precisely every two courses (fig. 3.130). The extrados is not as reg‐

ular and is flanked by ashlar masonry made of re‐

used stone blocks¹³⁸(fig. 3.131). The construction

Roman vaulting and construction in the Peloponnese: case studies 119

site plan level

2,32m

P. VITTI MMXIII (after W. Biers) 200 cm

2,20m 1,70m

Fig. 3.128 Corinth Aqueduct. Plan and elevation of the Stroggylo bridge (After W. Biers 1978, fig. 2)

1,90m

3,14m 2,73m

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Fig. 3.130 Corinth Aqueduct. View of the intrados of the arch of the lower tier of the Stroggylo bridge Fig. 3.129 Corinth Aqueduct. View of the Stroggylo bridge

Roman vaulting and construction in the Peloponnese: case studies 121

Fig. 3.132 Corinth Aqueduct. View of the opus mixtumfacing and one solid‐brick arch of the upper tier of the Stroggylo bridge Fig. 3.131 Corinth Aqueduct. View of arch of the lower tier of

the Stroggylo bridge

of the piers and of the lower tier was influenced by the irregular dimension of the re‐used blocks, which caused the imposts of the arch to be at different lev‐

els (fig. 3.128). The second tier had six brick arches, made with two rows of radially laid bricks (ca. 27‐

28x27‐28x2.8‐3.5 cm) as part of a opus mixtumwall (fig. 3.132). However, the arches rose from ashlar piers, made of more regular masonry than the lower tier. Bricks in the piers were inserted between the blocks, laid horizontally and vertically (fig. 3.133), in order to fill the empty areas between the blocks.

A detailed description of the bridge was included in the article published in 1978 by W. Biers¹³⁹.

Remarks on the Stroggylo bridge

Compared to the other sectors of the Corinth aque‐

duct this bridge is better built, even though the re‐

used material caused many irregularities, such as the different height of the imposts of the lower arch.

The builders did not remodel the blocks to make the ashlar work more regular due to the evident haste in completing the bridge. They used all the available material, including the many moulded blocks dis‐

mantled from many different buildings. The hypoth‐

esis of a reconstruction after the collapse of the

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original bridge is thus more than likely¹⁴⁰. To the original construction should be ascribed the specus, whose description¹⁴¹corresponds to the other sec‐

tors of the aqueduct. This allows a better under‐

standing of the events that occurred: the original mortared rubble bridge underwent severe damage most probably from a flood, and was reconstructed up to the point the specusentered the tunnel dug in the hillside. Ashlar blocks were used for the new construction as in other examples, such as the foot‐

ing of the piers of the Charadros bridge of the Argos aqueduct (fig. 3.46) or the ashlar construction alongside the Skoteini valley bridge¹⁴². The different technique of the upper tier of the bridge requires further discussion. At first glance it seems that the solid‐brick arches and the smaller building material

used above the piers of the second tier (fig. 3.128) were adopted in order to facilitate the construction of the upper parts of the bridge. Nevertheless it should be noted that putlog holes appear only in the upper part, corresponding to the brick arches and the opus vittatummasonry, and that on both sides of the bridge ashlar work was also used, but the blocks have irregular ends. On the south‐west end it is also possible to identify some blocks which were on the point of collapsing and stabilized by the construction of the opus mixtummasonry. The dam‐

age suffered by the ashlar masonry bridge can also be seen in the two southwest piers, where the open joints between the blocks indicate a sudden hori‐

zontal movement, such as happens in an earth‐

quake. The hollow sectors between the blocks were filled during the second reconstruction with bricks.

The timing for the reconstruction of the second tier could have been as follows:

‐ opening of putlog holes in the ashlar masonry of the piers, just below the final course of blocks, to create a scaffolding, laid on the recess between the first and the second tier and anchored to the wall through the putlog holes.

‐ Setting of the centering on top of the piers.

‐ Construction of the solid‐brick arches. The second level of putlog holes was placed just above the first row of arches, before the construction of the second row.

‐ Construction of the opus mixtumwall, filling also the empty areas left by the blocks which had col‐

lapsed.

‐ Some zig‐zag engravings in the mortar of the opus vittatum, described by W. Biers¹⁴³, suggest that the second reconstruction took place in the 5^thcentury.

Similar engravings are documented in fact on the 5^th century walls of the cult‐complex (bath A) in Argos (fig. 3.134). In short the Stroggylo bridge displays two different techniques for vaulting, one with stone voussoirs, the other with a double row of solid‐brick arches, and they belong to two distinct reconstruc‐

tions of the aqueduct built by Hadrian.

Fig. 3.134 Argos. Zig‐zag entravings on the mortar of the late phase of bath A

Fig. 3.133 Corinth Aqueduct. Stroggylo bridge. Detail of the ashlar masonry with mortared bricks inserted in the joints

The Great Bath on the Lechaion Road is situated close to the Forum. It is one of the most outstanding Roman buildings excavated in the Peloponnese. It had also a prominent position within the urban plan of the city. It was excavated in 1965‐68 and pub‐

lished in 1985.

Though not fully excavated, the extension of the building can be deduced on the basis of the city plan.

As suggested by J. Biers¹⁴⁴the area occupied by the bath complex could be as large as the insula running east of the Lechaion road (fig. 3.135) and the bound‐

aries of the bath complex could be established with a wall running along the minor streets and tabernae facing the main cardoconnecting the Forum with the Lechaion port (Lechaion street). The bathing fa‐

cilities were concentrated in a central block, with a

symmetrically organized series of rooms and corri‐

dors (fig. 3.136). Further information on the unex‐

cavated parts can be gathered from two drawings:

the first one dated 1802 and the other 1911¹⁴⁵. If so the bath complex can be compared to the Imperial baths¹⁴⁶, with an open‐air area around the bathing facilities, used for athletic or relaxing activities. The service corridors were located underground and had a separate entrance. This level has been only partially excavated and was independent from the bathing level.

The observations on the Bath are based on the pub‐

lications of J. Biers, from archive material¹⁴⁷ and from site visits¹⁴⁸. In the 1984 publication the south rooms of the baths, at present a private property and used as store‐rooms, were not included. How‐

ever, I visited these rooms, which still preserve the original vaults, though not accessing into them.

All the vaults were built in concrete, in a similar technique to the one in use in Rome. Archive pic‐

tures (figs. 3.137 and 3.145) show that before 1965 many chunk of concrete from the collapsed vaults were lying above ground level. These huge concrete masses had been partially cut by local villagers, probably to adapt them to new constructions. For this reason is not easy to establish to which part of the vaults they belonged nor their original location.

During the excavation the masses found in to rooms (1), (2) and (3) were demolished and removed to in‐

vestigate underneath (fig. 3.145). Under the large masses in room (3) other fragmentary masses were found and partially removed. The building tech‐

nique of these smaller masses seems to be different from the one of the larger masses.

Mass (EE) (fig. 3.145‐E), still lying to the northwest of room (1), consists of small poros caementaplaced in horizontal layers and mortar made with small ag‐

gregates, some of them of volcanic origin, as con‐

Roman vaulting and construction in the Peloponnese: case studies 123