New Integrated Knowledge based approachs to the protection of cultural heritage from Earthquake-induced Risk

Bet Shean
Conservation ot the Roman Bridge
OrdererSouthern Jordan Drainage Authority
DurationMars 2009
Implemented by: Eng. Yaacov Schefer
Ilan Phahima - Project Manager
Yoram Saad - Head of conservation project branch
Ezra Toill
Ilan Dalal
Eli Liberty
Dalia Dalal
Alexander Matzeq

The bridge is located in the Nahal Harod river channel, northeast of Beth Shean, at the end of the national park (Fig. 1).
The conservation work being implemented there is just one of the measures that are being taken to prepare a scenic path along Nahal Harod.
The bridge was built in the Roman period to span Nahal Harod and led those arriving at the city to the “Damascus Gate” (Fig. 2). The bridge collapsed when an earthquake struck the region on January 18, 749 CE.

It was originally c. 37 m long and c. 18 m wide and rose to a height of c. 14 m above the riverbed.
Two large impressive piers that were erected at an angle of 131° supported the center of the bridge. One of the piers was built of three arches (Fig. 3) and two other arches were constructed on the river banks. This complex bore three barrel vaults.

In 1993 Edward Kolick, an engineer with the Israel Antiquities Authority Conservation Department, conducted an engineering survey of the bridge. As a result of the survey findings the pier that bears the arches was stabilized by means of a concrete casting.
In the current project we treated the southern wall of the bridge along the side where the scenic path is to be built. The wall was preserved to a height of c. 10 m, but its core was exposed when the wall’s outer face collapsed which has resulted in accelerating the destructive processes and damage to the monument (Fig. 4).

The core of the wall was built of very large fieldstones (boulders), small stones, soil and bonding material. Over the years the rainwater has washed away much of the bonding material. Vegetation has taken root in the core of the wall and has also contributed to the deterioration of its stability. There is also the danger that stones will fall from the remains.
The goal of the project therefore was to conserve the southern wall, halt the destructive processes and eliminate any hazards that might endanger pedestrians walking alongside the wall.

The Conservation Measures Included:
Weeding the vegetation and spraying the architectural remains with an herbicide.
Restoring a section of the side of the wall using ashlar stones that were found in a heap nearby.
Reinforcing the exposed core of the wall with debesh construction.
Pointing up the joints in the stonework with lime-based bonding material and stone fragments (Fig. 5, 6).

The site requires constant upkeep that involves spraying the vegetation, filling-in missing bonding material, monitoring the preservation of the bridge remains and maintaining proper drainage around them.

To view the figures, click on the figure caption
figure 1. General plan of the city of Scythopolis – Beth Shean. Plan courtesy of Benny Arubas, The Hebrew University of Jerusalem.

figure 2. Aerial view to the southwest. The “Damascus Gate” and the Roman bridge are in the foreground of the picture. Photograph courtesy of Gabi Laron.

figure 3. Remains of the center piers in the river channel. March 2009.

figure 4. The southern wall during conservation treatment, March 2009.

figure 5. Pointing up the joints in the stonework.

figure 6. Stabilizing the exposed core of the wall.

figure 7. The southern wall after the conclusion of the conservation work, March 2008.

Additional Projects
 Scythopolis - Conservation of the Mosaic on the “Valley Road”
 Scythopolis - Conservation of the Mosaic in the Byzantine Forum
 Bet Sheʽan Project - Conservation maintenance

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