Report on the Intervention to Bam (Iran), in 2006 journal 3, news 2.pdf · Report on the...

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1. Introduction: Brief Notes Visit to Bam of L. Binda and

The visit to Bam was programcomposed by L. Binda, C. Blavelop a project for the repair aNevertheless during the visit 2005) it was possible to realisby a dense interconnected nelar constructive elements withmade in the lower part of Chiwith loss of materials and out“adobe” and wet clay as mortions, connections between wbetween vaults and walls. From the discussion with Dr.we were informed that: workauthenticity conservation crialigned walls, out of plumb), tional materials are going onexercises for the reconstructiotechniques are being carried ostabilizing better the mortar. After examining the situationof the Italian group it is clearreality solve more general prorather than concentrating on study possible solution to the Therefore the following pointfor the repair of the Chineh wfor the stabilization of ruins wtions for the repair of vaults aof the structural systems (Dr.

* University “Politecnico” of Milan. ** University of Parma. *** University of Florence. **** University of Padua.

Report on the Intervention to Bam (Iran), in 2006

uigia Binda*, Carlo Blasi**, Paola Condoleo*, Guido Licciardi*, Luigi Marino***, Claudio Modena****, Vincenzo Petrini*

of the Meeting of November 15, 2006, After the C. Modena *

med after the proposal made in 2005 by the group si, C. Modena, V. Petrini, A. Taliercio, A. Saisi, to de-nd restoration of a specific building (Mirza Na’him). (a previous visit was paid by L. Binda and A. Saisi in e that the lower part of the Bam Citadel is constituted t of low buildings: they are characterised by very simi- rather equal characteristics as follows: masonry walls neh which is highly damaged by large and deep cracks of plumb; upper part of the walls and vaults made by tar. No particular systems were detected for: founda-alls (apart from some remain of timber tie rods) and

Mokhtari, manager of Bam site and his collaborators s for repair partial and small reconstructions base on teria are been carried out (disconnected parts, non but also site workshops with the preparation of tradi- especially for the lowest part of the Citadel. In detail n of the vaults and domes according to the traditional ut together with materials testing with also the aim of

on site and after the discussion among the members that any technique applied to a single building can in blems concerning the are of the Bam Citadel; therefore a single building (or part of it) it seems more logical to typical problems. s seem to be the most important: to study techniques alls (injections, integrations, etc.); to study techniques hich will be left as they are; to study alternative solu-nd domes; to deepen the study of static and dynamic

Nejati was proposing to carry out tests on a shaking

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table: it would be important to study the typical problems of the Bam structures) in order to propose the “improvement” of the existing structures (particularly possible connections between walls or part of the structure which tend to separate, in order to reduce horizontal relative displacements, taking into account the necessity of re-alizing connections compatible with the overall stiffness: e.g. use of wood, injection with stabilized clay, etc.).

2. Report on the Mission of Guido Licciardi to Arg-E-Bam: Background

The activities of the Guido Licciardi in Arg-e-Bam (Iran) are framed in the Contract supported by UNESCO in Tehran concerning the activity of the research group com-posed by L. Binda, C. Blasi, L. Marino, C. Modena, V. Petrini from the Politecnico of Milan and the Universities of Padua, Florence and Parma in Arg-e-Bam, the core of the UNESCO World Heritage Site of “Bam and its cultural landscape” (N29 07 00.6 E58 22 06.5; listed as site n.: 1208), which has been damaged by an earthquake oc-curred on December 26th 2003. The scientific supervision is provided by Prof. Luigia Binda, Department of Struc-tural Engineering, Politecnico of Milan. The project is developing thanks to Dr. Eskandar Mokhtari, member of the ranian Cultural Heritage, Handcraft, and Tourism Organization as well as Director of the re-covery project of “Bam and its cultural landscape”.

2.1. Mission’s Objectives

Prof. L. Binda asked Guido Licciardi, PhD student in Cultural Heritage Preservation at the PhD School of the Politecnico of Milan to visit again Bam with the following tasks: Complete the architectural survey of the Mirza Na’im complex, which was the Quranic school of the city, and add information on its conservation state; Organize a preservation workshop together with local technicians and workers, in order to study, teach, and apply suitable methods for protecting and preserving ru-ined mud architectures respecting their authenticity; Organize training activities directed to the staff working for the Iranian Authorities.

2.2. Survey of the Mirza Na’Im Complex and its Conservation State Assessment

The Milan Polytechnic has been studying the old Quranic school of Arg-e-Bam, namely the Mirza Na’im complex, since the beginning of 2006. A survey was executed by Iranian Authorities earlier than the 2003 earthquake. During

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1. Arg-e-Bam (Iran), Mirza Na’im complex. A rectified mosaic of pictures showing one of the four façades overlooking the northern side of the main courtyard: the thin black line shows the building as it was before the earthquake; the red lines highlight the crack pattern caused by the earthquake. May 2006.

the first mission made by L. Binda, A. Saisi (Milan Politecnico) in 2005 it was de-cided that G. Licciardi, a PhD student who chose his PhD thesis on the study of the damages occurred to Arg-e-Bam should stay for a certain period at the site with the permission of Dr. Mokhtari to verify, update and digitalize at the scale of 1:50 the existing survey. During this first period spent by G. Licciardi in Bam Then, the four façades overlooking the main courtyard were surveyed and high-quality rectified mosaics of pictures at the scale 1:25 were done (see fig. 1). Additionally, a suitable computer-based system (G.I.S.) was set up to store all data concerning the building, with the objective of assessing its conservation state (see fig. 2). The survey was done employing only equipments that were locally available. Moreover, while doing the survey, the local technicians were involved day-by-day in all activities, and

s have been

ission, the survey was completed controlling all the plans and 36

to the Politecnico group to

conditions of the architectures before and after the earthquake; on architectural and

properly trained to carry on similar analysis without external assistance. During the mission carried out in December 2006, all technical materialoffered by Prof. Luigia Binda and Guido Licciardi to the Iranian Authorities, in order to inform them about the work already done also transferring them those scientific methodologies which are usually adopted for the study and protection of cultural heritage in Italy. During the same msections across all those rooms which were damaged by the earthquake but still standing and representing the crack pattern (see fig. 3). The comprehensive survey made by G. Licciardi is usefulcarry out an assessment of the state of conservation of the Mirza Na’im complex. This includes a better knowhow on all building techniques found at the site; on the


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2. Arg-e-Bam (Iran), Mirza Na’im complex. Computer-based G.I.S. assessing the conser-vation state of the building. May 2006.

3. Arg-e-Bam (Iran), Mirza Na’im complex. Some of the 36 sections composing the con-servation state assessment of the Mirza Na’im. December 2006.


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4-6. Arg-e-Bam (Iran), Mirza Na’im complex. Traditional lightening vaults to increase the building’s strengthen against the earthquake discovered on the roof during one of the mission carried out by

Milan Polytechnic. December 2006.

7. Arg-e-Bam (Iran), Mosque. Traditional horizontal wooden reinforcements to increase the building’s strengthen against the earthquake discovered on the north wall during one

of the mission carried out by Milan Polytechnic. May 2006.

structural damages caused by the earthquake; and all decay currently affecting the area. In the meantime, thanks to the strict collaboration with the Arge-Bam engi-neers and geologists the mechanical and physical characteristics and properties of the local building materials are now known. The survey allowed also to study solocal traditional systems which can be considered as used since the old times to im

he structure response against the earthquake were disclosed (e.g., lightening

me -

prove tvaults na see fig. 7). This knowledge can be of great importance for the design of future intervention

mely cunù, see figs. 4 to 6; and horizontal wooden reinforcements,


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for the improvement, preservation and restoration of the site because it is highly sustainable both from an environmental and economical point of view.

2.3. Preservation Workshop on Suitable Methods for Protecting Ruined Mud Ar-chitectures

During the mission carried out in December 2006, the local Authorities asked G. Licciadi to develop a suit-able method for protecting restored strservtectures which will be notrebuilt, but simply preserved

environmental sustainability;flexibilipreservation of all s age readable onto the structures fully respecting the history of the site; and

uctures and pre-ing those ruined archi-

due to their materials’ and historical authenticity (as de-fined by the Nara chart). One of the biggest problems of those structures is the protection from rainfall water and the consequent erosion on their surfaces (see fig. 8). Therefore, G. Licciardi has worked together with the Bam technicians and workers to a preservation workshop representing a collaboration between Iranians and foreigners. The method was supposed to have the following features: easiness; warranty of success; economic sustainability;

8. Arg-e-Bam (Iran), ruined building beside the Mirza Na’im complex. Before the preservation carried out

by Milan Polytechnic. December 2006.

ty to all situations found within the site;

igns of the earthquake to keep that historical p

respect of all International and UNESCO Charters and Recommendations in the field of protection and preservation of cultural heritage. All materials chosen had a very low impact, respectful of local culture, and easily available on site: clay; sand; straw; water; and cotton fabric. Their production and processing require very low emissions of CO2 and is fully re-spectful of the Kyoto Protocol for the reduction and control of the greenhouse effect. In brief, the sequence of actions comprising this method are listed below: wetting of top of the remaining walls to ensure a proper connection between existing


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and new materials; structural reinforcement of existing walls, through either new bricks crossing old and new structures, and execution of water injections to join all cracked fragments; placement of wet cotton fabric to separate old and new struc-

e 1964 Charter of Venice on the preservation of cul-

protect the preservation and create

Institutions involved in the activity.

it of L. Marino and V wer

irza Na’im on which to develop of proposal of interven-tion;

ve mentioned part; ite of possible intervention techniques.

ilding, the three rooms in the south-eastern corner n of the selection was due to the fact that these rooms

age and require intervention both of repair and of n they could be a good example on how to carry out

g parts of the building.

own in figs. 9-14.

ions com-

tures with a physical layer, leaving a trim that is directly visible allowing people to recognize the intervention; integration of collapsed parts in order to have only one horizontal layer, respecting thtural heritage. All new materials were suggested and analysed by the laboratory es-tablished nearby the site by the local Authorities; realization of a continuous layer made of mud bricks arranged in such a way to keep rainfall water away without flowing on the surfaces of the structures; execution of a small step made of clay to allow rainfall water dripping without eroding the surfaces of walls; laying of a fin-ishing layer of mud mortar added with straw toa surface that could be replaced in the next years without making again all previous work phases; and carving of the year 2006 in Gregorian and Persian calendar and placing of pictures showing the

3. Report on the Vis . Petrini to Arg-E-Bam

The objectives of the visit e: 1. selection of the part of M

2. detailed survey of the abo3. identification on s

After a general survey the buhave been selected. The reasoshow a significant level of damreconstruction. For this reasothe intervention also on the remaininA detailed survey of the rooms has been performed, looking mainly at the type and extension of damage; the results of the survey are shDuring the visit it was possible to collect some ideas on the possible intervention that lead to the project now submitted. The main line of intervention can be summarized as follow:

• the intrinsic capacity of the structures should be used as much as possible. The existing parts should be preserved and used with local integratpatible with local materials and techniques;

• at the same time, it is compulsory to implement a ordinary maintenance policy, repeated at regular time intervals. It is obvious that even the best interventions


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have a limited effectiveness without a maintenance programme done by trained workers, according to precise protocols and rigid timetables.

Beside this the recognition to the entire site of Arg-e-Bam allowed a better under-standing of: a) use of materials and construction technologies, typical of the site. More in detail, observations have been made on the adobe bricks and on the tech-niques adopted for construction/reconstruction. Particularly interesting was the use of solutions adopted for the preparation of the horizontal planes of the brick ma-sonries on top of Chineh made regular by bricks used to constitute a sort of opusvittatum or by trunks of palm tree longitudinally cut into half to form a peculiar opus craticium. Probably these timber elements had also been used to connect ma-sonries especially in the defensive walls of the Citadel where some timber ties still remain on place well shown by the collapse of the external leaf of th

e walls. b) principal collapse mechanism and decay processes.

in-plane shear, overturni

vertical collapses. The damages due to the seismic erepair, abandoned and by the rainfalls. The investigation made in Bam, thanks to th y years before the earthquake, or d rials and new bricks,

amage of earth struc-

ries opposite

on because the results of the destructions one masonries parts or

uni oconstrtransfo ms of the archaeological excava-tiodue tolarly ozontal

The collapse mechanisms mainly concern phenomena consequent tong.

Shear at the base of the wall andvent are generally worsened by the fact that many structures were left without any

e variety of damages (buildings abandoned manamaged by the earthquake and repaired with the same mate

buildings partially cleaned to open streets, buildings totally abandoned after the earthquake, use of modern electrical and hydraulic systems which certainly influ-enced the behaviour of the ancient masonries, use of vault filling with new bricks and/or rendering with the use of cement mortars) allowed to make some observa-tion on the dynamic of decay of the materials and of the dtures. The processes of formation of the archaeological ruins of earth masonto what happens to brick or stone masonries, may receive from the observation of Bam examples very interesting verificatihave no possibility of comparison. While in the case of st

ts f the masonry tend to survive also for long times so that their reuse for re-uction is possible, in the case of earth masonries the material tends to be rmed into earth. One of the principal proble

n of earth structures is due to the difficulty of recognising single elements also the effects of rain and moisture. Water causes an accelerated ageing particu-n collapsed elements, on interfaces between elements, on unprotected hori- surfaces.


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A particularly destructive cause is the capillary rise of water (when systems for the collection and elimination of meteoric waters are abandoned); this moisture tends

structeur in the

h

to create a very dangerous desegregation of the wall. The sillon demasonry as defined by Margueron in an horizontal continuous loss of the section of the wall which can cause overturning of it and settlements in the top parts. The dis-solution of the adobe bricks and pressed earth parts causes the loss of the wall leaves and hence of the possibility of recognising the courses, the wall texture and ence the possibility of finalised preservative interventions.

9. Localisation of the survey.


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10. Section A-A.

11. Section C-C and B-B.

12. Section D-D.

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e to the Expert Meeting

of the project principles, a list of pro rojected.

13. Section E-E, F-F- and G-G.

posals were p

On March 4, 2007, Prof. Claudio Modena attended the Expert Meeting organised atPardis Faculty of Fine Arts, University of Tehran, on behalf of the UNESCO Project partners. A ppt presentation was made on the work carried out by the Italian Group involved in the project, preliminary to the final definition of the project. In the presentation, after a description of the aims of the project and the presentation

4. Report of C. Modena on the Attendan

14. The other survey.

c

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The Meeting was an occasion for the partners to know other proposals, among them the optimal work carried out by the Group of the Soil Engineering Services (Tehran) on materials and repair techniques, particularly the use of Polypropylene pipes.

5. Restoration Project

5.1. Principles of the Pilot project:

- Use of the know-how from r to solve compatibility prob-lems with the existing materials and structures.

2. Partially collapsed vaults (R e missing parts should be recon-structed. (Room 3): This vault has to be repaired and completed. After posi-

ver the settle-

nstructed with the use of adobe.

etached have to be

e reintegrated with new

the local tradition in orde

- Preservation of the existing structures as much as possible. - Eventual small reconstructions with particular respect to the existing parts. - Improvement of the structural elements with weak response to the earthquakes. - Elimination of electrical wires and water pipes inside the walls. - Check of the rainfall water drainage.

5.2. Description of the pilot project

Three rooms 1, 2, 3 (fig. 15) at the South-eastern corner of the remains of Mirza N’aim were chosen as object of a proposal for intervention. Aim of the project is to propose some preliminary actions for the repair and recon-struction of the damaged parts of the two chosen rooms, according to the following program:

1. Vaults and arches. The collapsed vaults in Room 1 are the only elementswhich should be reconstructed (Figs.16-18). Details on the technique of con-struction are not given here, since the Iranian technicians and masons are very well skilled in this type of construction.

oom 1 and 3). Th

tioning of a provisional structure in timber, a tentative to recoment (fig. 19) should be made by using the provisional structure to force it. In case the tentative should fail demolition and reconstruction of the settled part has to be done. Also the missing parts of the top of the walls should be reco

3. Rendering and plasters. An operation to be carried out in room 1, 2 and 3 is a complete control of the plaster; the parts which are ddemolished, while the parts which have still good bond with the masonry should be left untouched. The missing parts should b


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materials. For the repair clay and straw should be used similar to the existing plaster. We also suggest to cover the last layer of the plaster only with clay, so that the plaster can be protected from external attach (insects).

4. Tie beams. In order to improve the “box” behaviour of the load bearing (and shear) walls it would be appropriate to introduce tie beams along the perime-

in coincidence with the spring of the vaults. Two different ques are proposed:

ams in the case of the collapsed vaults; details

he by inserting the beam

uld be o

in some buildings, m with square section joined as in figs. 22-

24. pipes suggested by the Soil Engineering Ser-rial presented by them to the Expert Meeting

tead of the timber ones

The connection between the tie beams at the corners of the walls can be

5.

rain size distribution of the ag-

6.

7. ction is missing in the section of the

ter of the roomsalternative techni

a) insertion of timber tie beof the connections between the beams of the longitudinal and transversal walls are given in fig. 20. In the case of the transversal wall where tvault is still present, this solution can be adopted from the top of the wall with a small demolition. The beams shodistributed along the perimeters. The timber tie beams can be of twtypes: 1) half cut trunk of a palm tree as found in Bamjoined as in fig. 21; 2) a bea

b) Use of the Polypropylenevices (Tehran). See the matein March 2007 at Pardis Faculty of Fine Arts, Tehran. This pipes should be inserted on both sides of the walls as tie beams insalong the whole perimeter of the rooms. The pipes can be inserted in niches excavated on the two sides of the wall where possible.

made through a timber cubic element to which the pipes are screwed. Repair of cracks. The cracks should be injected using a properly prepared grout made by simple clay or a mix made by clay and lime. A careful study of the w/b ratio, of the ratio clay/lime, of the ggregates and of the injection pressure (very low) has to be carried out before applying the technique and after studying carefully the dimension and distri-bution of the cracks. Missing materials or parts of the wall surface. Where small parts of Chineh are missing a sort of mould should be prepared and clay should be injected inside in order to reconstitute continuity and regular surfaces of the walls. Transversal connectors. Where connewall (e.g. separation between Chineh and adobe parts) Propylene pipes should be inserted transversally after coring the walls carefully. The connectors can be positioned at a distance of 70 to 80 cm. The connectors could be perforated and be used also as injectors of a fine grout made by clay and lime in order to


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15. Localisation of the rooms object of the pilot project.

16. Localisation of the collapsed and partially collapsed vaults.

17-18. Collapsed vaults in room 1.


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19. Partially collapsed vault in room 3.

20. Positioning of the ti er beams. mb


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http

21. Details of the timber beams.

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22-24. Details of the timber beams.


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obtain a sort of bond between the connectors and the wall. They can be

aken the walls should be closed. In particular thoms 1 and 2 and rooms 1 and 3 have to be closed af

adobe. A connection of the adobe with the rest of the

fixed also to the wall at the end on both sides. 8. Niches. Niches which can we e

two niches between ro -ter demolishing the thin wall.

The filling can be made with wall can be made as shown in fig. 25.

25. Niches: the filling with adobe.


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