ROMAN VAULTING AND CONSTRUCTION IN THE PELOPONNESE CASE STUDIES
Phase 3. Completion of the barrel vault
3.4 Corinth
3.4.2 The Great Bath on the Lechaion Road
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
Fig. 3.136 Corinth. Restored plan of the Great Bath on the Lechaion road (based on J. Biers 1985, plate 38)
phase II
?
? limit
of excavated area
D=
11,60
m
D= 7,00 m D= 4,40 m
D= 8,90 m
D= 10.70 m D=
11,70 m
500cm
P. VITTI DEL & REST MMXIII
N
?
1 3 2
7
8 9
4 5
phase III
POOLS
RESTORED WALLS EXTANT WALLS SUSPENDED FLOOR phase I
phase II
phase I
phase II
phase II
D= 3.90 m
D= 3.26 m D= 3.26 m
6
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124
firmed by the laboratory tests149 (fig. 4.30). This mass was apparently more than 2 m thick and can be restored as the corner of a very large barrel or groin vault. Different from these concrete vaults were other vaults that had brick ribs embedded in the concrete mass. The only visible example of the latter is the mass lying in the south area of room (3), composed of bipedalissolid ribs and concrete (fig.
3.153 above). Similar smaller masses were removed during the excavation and most likely belonged to the vault covering room (3). These masses had traces of a mortar layer (cocciopesto?) laid above a concrete layer of ca. 30 cm that covered the brick
rib150. Because the ribbed masses were found under the large concrete masses, it can be assumed that the vault with bricks collapsed before the large ones or, alternatively, it collapsed because the large masses of concrete fell from above to the room (3) covering. The study of the topographical location of these large fallen masses, not in the aims of the pres‐
ent study, could help in establishing their exact po‐
sition in the elevation of the bath. Nevertheless, as will be discussed further on, a restoration of these masses to room (1) and room (7) is possible. In fact both these rooms were much higher than room (2) and (3) (fig. 3.139) and thus their concrete vaults
Roman vaulting and construction in the Peloponnese: case studies 125
Fig. 3.138 Corinth. View of the Great Bath during the 1960s excavations (ASCSA Corinth Excavations, negative n. BW 1966 066 19) Fig. 3.137 Corinth. View of the Great Bath before the beginning of the 1960s excavations (ASCSA Corinth Excavations, negative n.
BW 1965 001 28)
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could have partially collapsed on the lower vaults.
Building phases
The bath complex was used for more than three hundred years, from the 2ndcentury to the 6th, as demonstrated by J. Biers. During this long period it underwent many modifications and reconstruc‐
tions, including the vaults. On the base of stylistic evidence of the marble façade on the court J. Biers dates the first phaseto the end of the 2ndearly 3rd
century, though recently a dating to the late 1stcen‐
tury has been proposed151. The building techniques show more similarities to the mid second century vaulting tradition, as consolidated after the death of Trajan, suggesting that the bath certainly did not be‐
long to late 1stcentury, but also not excluding a pos‐
sible construction earlier than the late 2nd/early 3rd‐century152. A systematic use of bricks in vaults, such as the horizontal bipedalis layers, is in fact recorded in the most impressive works carried out
Fig. 3.139 Corinth. Restored elevation of the Great Bath on the Lechaion road (based on J. Biers 1985, plates 39‐51‐52‐54)
in early 2ndcentury in Rome, so under Trajan and Hadrian. This hypothesis could be confirmed if the many sherds found in the broken vaults and dating to late 1stearly 2ndcentury153are considered. The second phaseis dated to the first half of the 3rdcen‐
tury, when the two apses in room 2 were added. The third phasedates to the end of the 4thcentury, fol‐
lowing the 365 and 375 earthquakes154. Room (2), used as a tepidarium in the first two phases, was transformed to a frigidarium, with two pools in the apses. Room (5) was probably rebuilt, while room (3) underwent repairs and two alvea(hot pools) were added in the apses. The fourth phaseis dated to the early 6thcentury. Changes affect both the ar‐
chitecture and the function. The windows of room (3) were walled (square bricks instead of triangular ones) and in the area facing the west façade a new brick construction with radial‐brick vaulting was added to house the praefurnium. This praefurnium served room (3), where a new pool was installed on the west side. At the same time the entrance from the Lechaion road was modified and a different ac‐
cess was used to enter the bath complex. The de‐
struction of the bath complex dates to the end of 6th/early 7thcentury.
Layout of the bath complex
The 1960s excavations were carried out in the area where some structures still were visible together with some of the collapsed concrete masses. The ex‐
tant walls above the ground were those of a large frigidarium(room 1). This room can been restored with a rectangular central room with two wings, on the south and north side (fig. 3.136). The plan is similar to the bath in Thouria (§3.8.1) which also had a central room with two opposing wings, where the pools were presumably located (fig. 3.215). A door placed in the centre of the west side of the cen‐
tral room of the frigidariumlead to a room which was originally heated (room 2 ‐ tepidarium) and from this to another heated room (room 3). Two other heated rooms (rooms 5 and 7) were located
Roman vaulting and construction in the Peloponnese: case studies 127
Fig. 3.140 Corinth. Great Bath on the Lechaion road. View of concrete wall faced with bricks. Bonding courses of bipedales are highlighted (room1)
Fig. 3.141 Corinth. Great Bath on the Lechaion road (Corinth).
Detail of a concrete arch with voussoir bipedales(room 1)
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to the north and to the south of room (3), though not accessible directly from room (3). The three heated rooms (3), (5) and (7) had a monumental façade fac‐
ing an open courtyard and decorated with a two storey architectural order. The two side rooms were not aligned with the central one, but were angled in order to form a concave form, oriented towards the entrance from the Lechaion road (fig. 1.135). The plan of this wing of the bath complex shows connec‐
tions with other bath complexes in Greece, such as the Northern Baths in Nicopolis and those of Ara‐
pissa in Sparta, that also faced a concave courtyard.
The identification of the donor of this Bath complex is still questioned. According to the chronology of the baths proposed by J. Biers it cannot be identified as the famous baths sponsored by the Spartan Eu‐
rycles, since Pausanias’ description155dates from be‐
fore the construction of the Great Baths.
Vaulting is crucial for the understanding of the ele‐
vation of the building. The only vaults that can easily be restored to their original height and shape are those of room (2) and room (7), being the only ones which still have traces of their springing. The former is a barrel vault, presumably much lower than all the other rooms. The latter is also a barrel vault which can be restored to a much higher level. Hypothetical restoration (fig. 3.139) shall be discussed after the description of the remains. Room (1) can be re‐
stored with a groin vault with two extensions to fit the rectangular plan of the room. The two wings fac‐
ing each other had lower barrel vaults oriented or‐
thogonally to the central room. The springing of the vaults can be located to just above the extant walls (fig. 1.148). The huge masses found in the site be‐
fore the excavation was begun must have belonged to the groin vault (fig. 3.145). The central room (3) had its axis parallel to the façade facing the court‐
yard (6), thus the barrel vault was supported on the east side by the wall towards room (2) and on the west side by the wall facing the courtyard. The thrust of the vault on the east abutment was coun‐
teracted by the thrust of the vault of room (2); on
the west side the thrust was entirely supported by the piers between the windows (fig. 3.139). The two heated rooms (5) and (7) were covered by barrel vaults. The walls supporting the barrel vaults were those perpendicular to the monumental façade fac‐
ing the courtyard (6), but probably the vault of room (5) was rebuilt and the new abutment sprung from the monumental façade, like room (3). The impost of the vaults of room (5) and (7) can be restored to a higher level than the two‐storey colonnade, on the basis of the still visible springing in room (7) (fig.
3.159).
The building material and techniques
Walls. The walls of the first phase were made of concrete faced with triangular bricks measuring ca.
27‐30 cm and 4 cm thick156(M=56‐65 cm). Courses of bipedales(side: 58‐60 cm, th: 5 cm) were laid reg‐
ularly every 60‐90 cm (2‐3 RF), though they did not always extend through the thickness of the wall (fig.
3.160). Above the bounding courses were the putlog holes (18x10 cm) necessary for the scaffolding.
Arches and flat arches. The passageways and the niches were covered by concrete arches, flat arches and relieving arches157faced with bipedalesset ra‐
dially (fig. 3.160‐C). Now and then bipedaleswere not cut and were set uncut to create concrete vous‐
soirs (figs. 3.142 and 4.15). The arches employed also the voussoir bipedales, 60 cm long bricks which taper from the extrados to the intrados in order to reduce the thickness of the mortar joint (fig. 3.141 arrows)158. Most of the arches sprung from a bipedaliscourse. The uppermost arch on the south wall of room (1), had bricks placed horizontally under the intrados of the arch. The horizontal bricks created two separate structures, i.e. the wall and the arch (fig. 3.142), thus transferring most of the weight of the above structure to the pillars support‐
ing the arch.
This solution was probably adopted to concentrate the weight on specific locations of the structure.
Fig. 3.142 Corinth. Great Bath on the Lechaion road. Sketch with construction details of room (1)
Roman vaulting and construction in the Peloponnese: case studies 129
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130
Concrete. The adoption of bounding courses to‐
gether with the different types of arches, combined to add strength to the structure, were not the only solutions perfected to achieve a high‐standard con‐
struction. The architect in fact took great care in the composition of the concrete, which was differenti‐
ated according to its location in the structure. Con‐
crete was generally made with caementa(pieces the size of a hand‐span) carefully placed in horizontal layers and well compacted (fig. 3.143). In the walls caementa were either calcareous or poros(sand‐
stone) stones with a few fragments of brick. In the vaults, however,, the concrete was made exclusively with porosstones. Also the mortar had a different composition. The mortar used for the walls was lime‐putty mixed with different types of stones, mainly small gravel sieved to different gradients (fig.
3.144). The mortar used in the vaults had smaller aggregates, some of volcanic composition (fig. 4.29).
One of these aggregates was tested in the laboratory, and its composition confirmed159. Systematic labo‐
ratory research, not included in this study, can give more information on the composition of the mor‐
tars, although it is clear that the architect took great in selecting materials.
Studies that are being carried out on some of the Im‐
perial constructions of Rome show that Roman builders were extremely selective in choosing the material for concrete. Not only lightweight material was used for the caementaof the vaults but also vol‐
canic sand and pomice, in order to reduce weight and add strength to the mortar160. In some cases, to add stiffness to concrete, in critical point of the walls and vaults, brick was used instead of tuff161. In a fashion Corinth’s architect carefully selected the ag‐
gregates and the caementanecessary for the opti‐
mum concrete. In the flat arch and relieving arch above the passageway which connected room (1) to room (2) the concrete was made of brick caementa, instead of limestone caementa(fig. 3.149).
Fig. 3.143 Corinth. Great Bath on the Lechaion road. View of the concrete wall in room (7). Bonding courses of bipedalesare highlighted
Fig. 3.144 Corinth. Great Bath on the Lechaion road (Corinth).
Detail of the mortar used in the walls of room (1)
Description of the structures
Room (1) (frigidarium) was a rectangular room 11.60x15.25 m with two long rectangular rooms 6.75 m wide, opening on the long side of the central room (fig. 3.136). At the very end of these two rooms were cold pools. A third pool, 1 m deep, was located in the central room and was circular in shape (diameter 6.50 m). The restored plan features a cross shape, with the main axis oriented east to west, while the two rectangular pools were located on the transversal axis162. The walls were 1.10 m thick and had rectangular and circular niches, with arches and flat arches with relieving arches above them (fig. 3.148). Since the extant walls do not pre‐
serve any trace of the impost of vaults, they have to be restored above the present top of the walls. A photo taken in 1965, before the beginning of exca‐
vations (fig. 3.145), gives some useful information on the vaults. In this photo two fallen masses can be
distinguished for the impressive dimension: mass (EE) (fig. 3.145‐E) and another mass, labelled C1 and C2 in fig. 3.145. Both the masses can be restored to the groin vault of room (1) and were covered by crushed‐brick mortar, which waterproofed the flat extrados of the vaults. Block (EE) had fallen from the northwest corner of room (1), because of the two orthogonal faces faced with bricks (fig. 3.146), with a cornice on one of them (fig 3.146‐A). The gabled surface of the extrados of mass (EE) shows that the profile of the roof was similar to the one adopted in the imperial baths in Rome. The original elevation could thus be restored as in fig. 3.139, with a ther‐
mal window facing towards room (2). The channel under the window drained the water from room’s (2) roof. This drain is still preserved today, but in 1965 was somehow longer, since the parts labelled (A) and (B) in fig. 3.145 were removed during the excavations.
Roman vaulting and construction in the Peloponnese: case studies 131
Fig. 3.145 Corinth. View of the Great Bath before the beginning of the 1960s excavations (ASCSA Corinth Excavations, negative n.
BW 1965 048 01)
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132
At the beginning of the excavation there was also an‐
other huge mass, visible in fig. 3.138, probably mass (DD), that had a similar crushed‐brick layer and drain channel to collect rain waters (fig. 3.137 arrow), that was laying in room (3) and thus could hardly be restored to room (1), while it could have fallen from room (7).
Room (2) was connected to room (1) by a 2.20 m wide passage, while there were two 1.60 m ca pas‐
sageways to room (3). It was a narrow 9.80x4.40 m ca. rectangular room with two apses, where two cold pools were placed later. The floor was heated with the hypocaust system163, while the walls were not heated. A flattened apse on the east wall and was necessary to hide the different thickness of the wall, since this wall was wedge‐shaped in plan (fig.
3.136). The room was covered by a barrel vault, with the impost at 6.85 m from the floor level. The concrete vault was built of horizontal layers of poros (8 courses of caementaevery 60 cm). Every 55‐75 cm164 were bipedalis horizontal bonding courses (fig. 3.147), extending through the thickness of the vault. The extrados of the vault can be restored on the basis of the layers of cocciopestoon the top of the extant masonry165 (fig. 3.162). It should be noted that while the caementiciumused for the vault was made with the light‐weight porosstone, the arch covering the niche and the uppermost masonry under the spring of the vault were both made with brick caementa(fig. 3.149). It is likely that the brick was used to strengthen the masonry. There is simi‐
lar use of the brick caementainstead of the poros ones in the flat arches and in the masonry under the
Fig. 3.146 Corinth. Great Bath on the Lechaion road. View of room (2) from west. A) cornice made with bipedales; B) crushed‐brick mortar. Arrows point on the bipedalescourses in the concrete vault
Fig. 3.147 Corinth. Great Bath on the Lechaion road. Sketch with construction details of room (2)
Roman vaulting and construction in the Peloponnese: case studies 133
second phase (fig. 3.136)167. In the last phase the ad‐
dition of a third pool facing the courtyard was part of major changes to the original layout of the bath, since the courtyard was occupied by a huge furnace, covered by a solid‐brick barrel vault (fig. 3.150168).
These modifications can be related to a new func‐
tional layout of the room following a “massive de‐
struction which seems to have affected the east side of the room”169and might have affected the vaulting system too. The evidence for this could come from spring of the southern niche in room (3).
Room (3) was a rectangular room, ca. 8.9x12m, with two apses on the southern and northern ends.
The apses were 5.75 m wide and 1.42 deep. It is not possible to identify the modifications carried out in the area of the alvea(hot pools), but it is clear that originally the room had only a central pool, 20‐25 cm deep 166, meaning that it was not used for bathing. The two apsidal pools were added in the