| The Old City of Akko (Acre) |
| The Eastern Land Wall |
| Conservation of the sentry boxes |
| Orderer | The Old Acre Development Corporation, Ltd |
| Duration | January-October 2005 |
| Implemented by: |
Arch. Vardit Shotten-Hallel
Shauli Sela'
Eng. Yardena Etgar
Daniel Seeboni
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The conservation intervention in the sentry boxes (“the guard towers”) in the eastern land wall of Acre was conducted following the collapse of the southwestern corner in the northern guard cell. The Conservation Department of the Antiquities Authority was requested to prepare the planning and implement the work after the Akko municipality issued an order to eliminate the dangerous situation present in the two guard towers.
From the historical information gathered we know that in 1940 construction intervention was carried out in the cells at which time the British replaced all of the stones in the southern cell and executed repairs in the northern cell.
The physical-engineering survey conducted prior to the work revealed that most of the engineering problems stemmed from a lack of maintenance. From a conservation standpoint the two cells were unstable. The following structural elements in the northern tower collapsed: the southwestern column and the cantilever below it. The southern cell was in a slightly better condition but here too the neglect was apparent in the stone cantilevers that were worn and cracked.
The conservation problems that were identified at this stage are:
1. In both cells the bottom support was no longer functioning.
2. The weathering of the kurkar is a result of natural processes influenced by climatic conditions, salts and high humidity.
3. Oxidization of steel elements that were installed between the stones by the British caused swelling, and as a result of this, the cracking and fracturing of stones. An iron gate that was installed in the entrance to each cell had rusted and the hardware used to attach it to the stone caused the stone to break. The stones in the cells suffer from a multitude of fissures. The poured lead in the connections between the cantilever stones has swelled and has deeply cracked the stones and even fractured them.
4. The use of cement-based bonding materials in later repairs has resulted in accelerating the weathering of the stone. A side effect of the neglect together with the humidity is the spread of vegetation whose roots cause the stones to separate and crack. The bonding material in the joints of the stonework is missing and consequently the stones have moved and settled.
After the problems and their causes were identified it was decided to dismantle the sentry boxes and the stone cantilevers on which they were built in order reconstruct them firmly.
During the dismantling process several construction specifications became apparent that were previously unknown:
1. We found holes c. 5 cm in diameter in the upper and lower sides of each stone in the original construction. Lead was poured into these holes as a vertical fastening specification between the stones.
2. Steel rods between the cantilever stones formed vertical connectors in addition to the horizontal steel specifications that were known.
3. The stone cantilevers were not long and much less of them was resting on the wall than we initially presumed.
4. Some of the consoles were built of several stones.
The conservation intervention consisted of: the orderly dismantling of the two cells; conservation of the stone; repair of the stone; replacement and fabrication of missing stones; incorporating stainless steel beams as a load bearing system inside the stone cantilevers; reassembling the sentry boxes carefully using as much of the original stones as possible and the installation of new doors and grillwork.
To view the figures, click on the figure caption
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