**2. Historic brick bridge**

**56** The bridge was located at the narrowest point of the pond (**Figure 2**), still reaching a respectable length of 91.5 m, its width being 3.70 m. It consists of semi-circular *A Deep Review on a Historical Brick Bridge in South Moravia; Reconstruction and Assessment DOI: http://dx.doi.org/10.5772/intechopen.102602*

**Figure 2.**

*A view map of the Mikulov estate drawn up in 1672 by Clemens Beuttler of Ebelberg for Prince Ferdinand of Dietrichstein (a map of the Mikulov estate from 1672), the cut out of the Mikulov estate's land register 1629 [1].*

vaulted arches, divided by pilasters with double-sided pyramidal edges (**Figure 3**). The bridge deck was lined with a solid, approx. 75 cm high parapet wall. The outer fully bricked sections were ended by short open wings with decoratively shaped fenders at the ends (**Figure 4**).

The tenth section from the south had originally been equipped with a wooden lifting deck; it was still present on the maps from as late as the 1830s (**Figure 5**), but shortly afterward it was removed and the empty section was bricked up similarly as the other parts of the bridge. After being vaulted, the part of the deck in the originally unfilled segment was also paved with limestone blocks (**Figure 6**) [1].

The existing intact paving in the entire area of the bridge deck made of limestone blocks was found during the restoration, accompanied by an archaeological survey*.*  The paving is well-preserved on about 90% of the surface and during the fieldwork was carefully covered. The stone pavement had an approx. 5–10 cm thick layer of fine limestone gravel on it.

The engineering design of the bridge was very well thought-out. The part of the columns below and slightly above the water level was made of large blocks of hewed limestone, the remainder was built of brick (**Figure 7**). The bridge arches themselves widen at two points towards the base and the bricks on the front face are hewed in the shape of a decorative arch keystone. Also, the pyramidal shape of the edges

#### **Figure 3.**

*A cut out of the overall 3D model of the bridge created by laser scanning within an archaeological survey in 2019. A later alteration is visible on the first arch from the left, where the extended vault replaced the old wooden drawbridge [2].*

*Applied Methods in Design and Construction of Bridges, Highways and Roads - Theory and Practice*

#### **Figure 4.**

*The original quoin stone found before the present restoration of the bridge started. The uncovered fender was used in making replicas during the heritage restoration.*

#### **Figure 5.**

*Historical plan of the original bridge design still with the lifting deck, undated map 107 [1].*

#### **Figure 6.**

*The find of the original limestone pavement.*

was obtained through the final hewing of the brick masonry to shape (**Figure 8**). According to the documentation, the bridge edges were plastered. On the surface of several bricks, there are still noticeable plaster-coat remains.

Uniquely preserved is the drainage solution for the bridge deck, using drainage openings lined with curved roof tiles, known as tegula. Based on samples of the original historical material of the bridge deck and their laboratory evaluation, it was *A Deep Review on a Historical Brick Bridge in South Moravia; Reconstruction and Assessment DOI: http://dx.doi.org/10.5772/intechopen.102602*

#### **Figure 7.**

*To determine the foundation of the bridge, it was necessary to carry out a borehole probes.*

#### **Figure 8.**

*A detail of the original edge of the bridge column. A detail of the edge of the bridge column after the repair.*

found that the original bridge deck was threshed on an aluminous-stone backfill with clay waterproofing at the level of the drainage pipes. The thickness of the clay layer was about 60–100 mm.

The Mikulov estate had sufficient quarries supplying stone for construction elements of the bridge as well as for its pavement and penning of the deck. The 17th century land registers record 13 of them. They were in the different localities of the estate, limestone was predominantly quarried between Mikulov and the Portz Island (geological locality Mušlov is a former large sandpit, the main rock type is sands with algal limestone bodies, containing mollusc fauna). Bricks, too, were of local origin, as shown by their marking with the letter N—Nicolsburg (currently Mikulov) (**Figure 9**), a mark or production stamp of identification. The bricks are slightly larger than the current solid fired bricks (approx. 150 mm/300–310 mm).

#### **Figure 9.**

*Baroque bricks taken out of the loosened structures of the bridge were reused in its restoration. They are marked with the letter N (Nicolsburg).*

Good quality of original bricks was given by the technology of the production process, in the 17th century, building materials were produced more slowly. The bricklayers of that time stuffed the clay into the moulds and let them dry for a month before firing. This production process guarantees high-strength bricks. In the first half of the 17th century there was only one brickyard in Mikulov, but with its three kilns surprisingly large for its time. Given the same technology, it was also possible to burn lime at the brickyards, used in turn to make mortar for the bridge construction. In the mid 17th century, perhaps owing to the consequences of the Thirty Years´ War, only two brick kilns were left in operation.

The golden era of the summer residence complex suddenly came to an end in 1872 when, in consequence of building a railway line to Mikulov (**Figure 10**), the pond

#### **Figure 10.**

*A new railway line under development (1872) was drawn on the older map. The original pond was then already drained (1855–1857). (Imperial obligatory imprints of stable cadastre map from 1826) [3].*

*A Deep Review on a Historical Brick Bridge in South Moravia; Reconstruction and Assessment DOI: http://dx.doi.org/10.5772/intechopen.102602*

**Figure 11.** *A view of the bridge at the time of project preparation before the renovation.*

was drained and the bridge lost its main function. It continued to serve as the crossing over the Rybniční brook. The pond was later restored in the northern surroundings of the island, though due to the railway line it could not be refilled in its original scope, its southern part changed into a wetland forest and meadow. The island became a peninsula and the essentially disused bridge was no longer maintained. Thanks only to the inimitable quality of the bricks made by Mikulov's skilful brick makers of the 17th century, the construction has survived until today. As the whole area had been tightly enclosed over the period of 40 years under the totalitarian regime, the bridge was in a state of disrepair (**Figure 11**), when the restoration was carried out from 2019 to 2020.

The bridge is, in all respects, a unique structure also on a broader European scale. It fascinates by its age, and it is unparalleled as to the selection of the building material and design. It differs from the common pond and river bridges also in its function. Being built as part of a well-considered architectural plan including the other buildings on the island and landscaping, its form elevated the aesthetic effect of the whole majestic complex. The builder had not only in the mind the visual impact of the bridge, but also, through the incorporation of the lifting deck as an element of defensive architecture, he sought to create an impression of a fortress-like character of the place. It is a consummate engineering work that leaves us with the question of who was its originator—perhaps one of the northern Italian fortress master builders, who at that time worked for influential, politically active aristocrats in Bohemia and Moravia.
