Problemy konstrukcyjno-konserwatorskie w kompleksie "Emir Kurkumas" w Kairze

Although the state of preservation of the Ameer Qurqumas complex, Cairo can justly be described as one relatively satisfactory it is beyond any doubt that it requires a good deal of constructional work aimed at strengthening of structure of the preserved monument that at the same time will enable its adaptation to the new functions. The above complex was already subjected to some preservating treatments in 1916—>18 and in 1941—43 which, however, did not bring as a consequence any total strengthening of its structure as their scope was confined to fairly negligible superficial repairs. The works carried out at present by a group of Polish experts were purposed to cover the following two stages: (a) a detailed reconnaissance and examination of destructions and technical assessment of structural qualities of materials applied for its erection as well as that of usability of the preserved elements, (b) preparing of general scheme of the whole project and designing for both conservation and constructional works. In the course of preliminary works enabling to underhas been carried out of causes of destruction and also carefully calculated the stresses present in the most loaded piers and walls as well as the values characterizdng the strength of original materials. In view of differences apparent in structural patterns in the separate portions of the comdlex each of them has been individually considered as a structural entity with the appropriate allowances made for a broad margin of security. To be most endangered proved the piers in mausoleum for which a need has arisen to make a set of detailed statical calculations. It followed from the above calculations that the “opus emplectum” system adopted in the building is being loaded nearly up to the extreme limit of its theoretical strength wheraas the foundations are in perfect condition and do not need any strengthening at all. The strength of limestone used for construction has, as a resut of tests, been determined as that amounting to a value of 120 kG/cm2 whereas that of mortar as that of 8 kG/cm2. The above tests have been carried out by the use of two methods that is that macroscopic and in a laboratory. In addition to the above tests has been examined the stability of walls and in particular the cracks were tested by placing of control cement “cakes” with glass strips inserted between them; finally, the preserved structural elements made of timber were also subjected to examination. A number of constructional measures has been provided within the general scheme. As the most complicated among them are to be named those connected with strengthening of piers in mausoleum where the cracked stone blocks are to be replaced with new ones meetings the extremely severe requirements of description and those of execution techniques. In some places where the existing walls erected from limestone blocks have completely lost their cohesion it has proved indispensable to provide for anastilosis. In places where the basic mass of walls has decayed and poured the thus formed cavities and cracks will be filled with a thin cement mortar injected by pressure. The design provides also for technical requirements of execution of the building’s new portions where those original have totally decayed, as it is the case, for instance, with walls, floors or vaultings. As the traces of the original structural patterns, corresponding with that required by the future functions ■and structural strength have been preserved almost in all portions of the buiding the new elements will in principle resemble those original as to their basic forms and materials. In addition to the detailed outlines to the design have been included the requirements that are to be complied to by the newly applied building materials and so, for example, the stone material should be of the same kind as that used originally, the mortars should have the strength of 15 kG/cm2 and for their preparing should be used the quartz sand. A permanent supervision over the building work performed by an engineer-conservator has been planned which the provision is in full accordance with general practice adopted in Egypt. The works conducted in the Ameer Qurqumas complex will allow to gain some new experiences in conservation of the monuments of Islamic art and to utilize them both in Poland and in other objects im Egypt.