STONE ARCHITECTURE

THE CONTRIBUTION OF THE ARCHITECTURE SCHOOL OF BARI TO THE STUDY OF THE HISTORICAL HERITAGE OF THE COUNTRIES OF

EASTERN EUROPEThe cases of St. Gervais at Paris, Sinan’s Mosques and Armenian churches

Professor Claudio D’Amato Guerrieri

Faculty of Architecture – Polytechnic of Bari

ITU – Istanbul Technical University, Istanbul, 27th November 2006

THE CASE STUDY OF THE RECONSTRUCTION OF THE PEDIMENT OF THE CHURCH OF ST. GERVAIS IN PARIS

Entreprise Chevalier SA – Paris2002

The façade of the Church of Saint Gervais, a building in the late gothic style, is the first classical façade in Paris.Built between 1616 and 1621 to a design by Salomon de Brosse, it is characterised by the superimposition of three architectural orders (Doric, Ionic, Corinthian) and a monumental curved pediment, originally crowned laterally by two large sculptural groups.

Façade of the Church of Saint Gervais:

original state (engraving by Marot)

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Façade of the Church of Saint Gervais:

actual state before the reconstruction of 2002

The 48 metre high façade, built with blocks of Saint-Maximin stone, is a challenge to the laws of static.Its pediment, weighing c. 400 tons, is composed of a depressed arch, in the central part, with a span of 6 metres, a depth of 2.5 metres and a height (from the springing line to the key stone) of only 70 centimetres; it exerts a strong lateral thrust (of circa 25 tons).

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The static role of the sculptures: the “pinnacle effect”

The two sculptural groups not only had an aesthetic but also an important functional role: they verticalized the lateral thrusts of the vault, according to the principle of the pinnacle, thereby assuring the stability of the whole. The removal of the statues after the French Revolution signalled the beginning of a process of dilapidation for the pediment due to the structural instability caused by the new arrangement.

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Portal and hood in reinforced concrete carried out in the restoration of 1904

In 1904 an initial intervention of static consolidation was carried out; but the bracing structures in reinforced concrete (for the portal and the hood) behaved like foreign bodies and further compromised the stability of the pediment.

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

SURVEY AND FIRST DESIGN HYPOTHESIS

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Measured drawing of the pediment using both manual and digital instruments, drawings, digital model

The measured drawing of the pediment was executed with manual and digital (3D scanner) instruments. Its actual state is depicted both by traditional means (plan, section, perspective) and by a three-dimensional digital model.

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

DISMANTLING THE PEDIMENT

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Frontal view of the different layers of the vault of the pediment:

1-portal in concrete; 2-first course of the vault; 3-second course of the vault; 4-hood in concrete

4

3

2

1

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Existing assemblage: plan of laying of the vault with metal clamps and tie-beams

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

DESIGN FOR THE NEW PEDIMENT

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Design of the abutments of the vault

The design for the new pediment is based both on [knowledge derived from] an in-depth study of the original building – that thus functions as a text – and on the theoretical knowledge and technical know-how of stereotomy.For the abutments of the vault a horizontal assemblage with internal joints in a radial pattern are adopted (using the principle of the original assemblage).The masonry assemblage is held in place through the use of steel clamps and nails, while the vault is conceived as maxi-ashlars fixed to the wall of the tympanum with steels stays.The design for the new pediment was elaborated and tested in all its aspects with digital modelling instruments.

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Design for the abutments of the vault:

the existing solution (on the left) and the designed solution (on the right)

Design for the abutments of the vault: the disposition of the metallic clamps and nails

Design for the central part of the vault: anchorage of the maxi-ashlars to the tympanum

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

CONSTRUCTION OF THE NEW PEDIMENT

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Cut of stone: computer aided manufacturing and testing the shape of the voussoirs with the “panneaux” drawn by 3-D model

Stone from the Saint-Maximin quarry is cut using both automated (CAM) and manual workmanship (finishing and testing).Moreover, using a digital model reduces the on-site time to only three weeks, thereby considerably lowering costs.

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Frontal view of the new pediment

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings.

Design and Restoration

Technical typologies

Theoretical model

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings.

Design and Restoration

During his long carreer, at first as main general of Corps of Engineers’ and then as chief-architect of the Ottoman Empire, Mimar Sinan designes especially new buildings, carring out more than 400 works, but he also restores historical buildings during his many travels all around Empire lands.Among his many architectural and construction experiences the most original technical innovation is the structural use of iron.Both in Sinan’s masterpieces for imperial patrons- like Suleymaniye Mosque - and in his main restoration works - like Haghia Sophia – the iron is used in a similar technical way.

Technical typologies

Theoretical model

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings.

Design and Restoration

Technical typologies

The principal technical typologies in Sinan’s structural use of iron are four:

•clamps and pins

•beams

•chains

•reinforcement ring

Theoretical model

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings

Design and Restoration

Technical typologies

- clamps and pins: Clamps and pins in stone masonry construction are used in ottoman architecture even before Sinan in order to stiffen the building system especially in case of seismic actions, even if some scholars think they were used as a auxiliary element in structural assemblage; the pins are used to connect, in vertical, the ashlars of the several rows, both in masonries and pillars. On the contrary, the clamps are used to connect, in horizontal, the ashlars of the same row or to vice structurals elements; this is the case of the anchorage between arch and masonry.

- beams

- chains

- reinforcement ring

Theoretical model

Kara Ahmed Pasa mosque, Istanbul – Iron pins of the porch ashlars (photo – Nicola Parisi) I

Kara Ahmed Pasa mosque, Istanbul – Pre-arrangement for clamps (photo – Nicola Parisi) I

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Microsystems of iron anchorage (pins and clamps) are generally used to build minarets.All the stone ashlars are connected both in vertical and horizontal, like the jutting parts usually ornamented with muqarnas.

(photo – Amir Pasic)

Selimiye Mosque, Edirne – The reconstruction of Selim II Mosque minaret shows that the old techniques used in Sinan’s construction site are the same of Restoration.

(photo - Vakiflar Genel Mudurlugu, Edirne)

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

(photo - Vakiflar Genel Mudurlugu, Edirne)

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings

Design and Restoration

Technical typologies

- clamps and pins- beams: beams in wrought iron and bricks are often used to build ceiling whit level intrados.This technology was applied to the secondaries roofings of marginals openings.Sometimes the beams wasn’t load-bearing but built a redundant reinforcement strutting in case of earthquake.

- chains

- reinforcement ring

Theoretical model

Selimiye, Edirne – Photo by Vakiflar Genel Mudurlugu I

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings

Design and Restoration

Technical typologies

- clamps and pins

- beams

- chains: the firsts chains used by Ottoman architecture from 1450 was in wood. Only during the XVI century the iron was used. The chain is a structural element utilized to force back the horizontals thrusts in the vaults. Mostly it is used in the barrel vault not much emploied in the Ottoman architecture. In Kara Ahmet Paşa (1558) Mosque, the chains of the laterals gallery, barrel vaulted, are one of the firsts examples.

- reinforcement ring

Theoretical model

Mihrimah Sultan Mosque, Edirnekapi Istanbul – Original info-ghraphic model by Nicola Parisi I

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings

Design and Restoration

Technical typologies

- clamps and pins

- beams chains: In Selimiye’s quadriportico, the whole chains system can’t be supposed for a classical restraint of the horizontals thrusts; in fact, the thrusts are often balanced by supported arch.It is necessary to think at a reticular complex system of spatials bars assuring a global rigidness for structures stressed by earthquakes.

- reinforcement ring

Theoretical model

Selimiye Mosque, Edirne – Quadriportico (photo di Nicola Parisi) I

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The structural use of iron in Sinan’s domed buildings

Design and Restoration

Technical typologies

- clamps and pins

- beams

- chains-reinforcement ring: the reinforcements through the iron ring are used beginning from half of the XVI century. The works of Sinan are the first buildings built with similar techniques. The technique of the iron reinforcment ring is employed by the Ottoman architect both in the new projects and in the structural improvements of ancient buildings.

Theoretical model

Mihrimah Sultan Mosque, Edirnekapi Istanbul – Original info-ghraphic model by Nicola Parisi I

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The turbe of “the Magnificent” Solimano and of Selims II introduce iron ring on different levels; some are broadly visible, others are totally concealed.The iron ring aim to contain the radial horizontal pushes produced by the domed structures, avoiding the break-ups along the meridian lines.

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

The technique of the metallic reinforcement ring postpones the commune employment of the chains. In the Selimiye mosque in Edirne the system of chains that connect the vertexes of the central octagon reconstructs a discreet ring that contain the horizontal pushes during the normal state of gravitation of the weights and guarantees the mutual distance of the vertexes during a seismic event.

Selimiye Mosque, Edirne (photo by Nicola Parisi)

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

Among the most important restorations of Sinan it needs to remember that for the Saint Sophia basilica. Sinan in this restoration ordered the construction of buttresses set to the masonries for a great balancing of the pushes and put a reinforcement ring of the dome that introduced problems of equilibrium since her first construction.

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

ARMENIAN MEDIEVAL RELIGIOUS ARCHITECTURE – FORM AND CONSTRUCTION

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

DOMED CHURCHES IN AYRARAT, 6th – 13th century: some case studies

Kat‘ołikē , T‘alin - Surp Hovhannēs church at Mastara - Surp Grigor church at Aragats, 7th century a.D.

The use of three-dimensional modelling for damaged buildings and for the konwledge of the built architectural forms

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

CROSSED ARCHES IN MEDIEVAL MONASTERIES: architectural types

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

RESEARCH OUTCOMES: 1. final synthesis studios

Medieval monasteries of northern Armenia: valorisation and design for the reconstruction of lost or damaged buildings

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

RESEARCH OUTCOMES: 2. projects (with CSDCA, Milano)

Ereruk ‘, 5th century (?): survey; real and ipothetical three-dimensional reconstruction of the monument

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri

RESEARCH OUTCOMES: 3. publications

The cases of St. Gervais at Paris, Sinan’s mosque and Armenian churches

Prof. Arch. Claudio D’Amato Guerrieri