Hagia Sophia

By Sultan AlSamhan

Table of Contents

Introduction ! ! ! ! ! ! ! ! ! ! Pg 3

Now & Then! ! ! ! ! ! ! ! ! ! Pg 6

Design & Reconstruction! ! ! ! ! ! ! ! Pg 9

Structural Analysis! ! ! ! ! ! ! ! ! Pg 11

Appendix: Illustration! ! ! ! ! ! ! ! Pg 15

Bibliography! ! ! ! ! ! ! ! ! ! Pg 18

Introduction

! Justinian’s church of Hagia Sophia was originally established in 537. A

reconstruction of the central dome in 562 provided the church with its pronounced form.

It was a space with a unique self expression that in essence consisted of a dome on a

square plan, with wide spanning vaults and interpenetrating spaces.

! It’s magnificence caused the building to become a legend, sending aftershocks

that elevated the conventional ways of building churches in the west throughout the

twelfth and thirteenth centuries. Even though no new forms were developed, the

ambition and scale of this project was only comparable that of the Pantheon four

hundred years earlier and the dome of the Florence Cathedral much later.

! Procopius made the following assessment: “So the church has become a

spectacle of great beauty, overwhelming to those who see it and altogether incredible to

those who only hear of it. For it soars to a height to match the sky and . . . looks down

upon the rest of the city . . . Its breadth and length have been so fittingly proportioned

that it may rightly be said to be both very long and unusually broad. And it exults in an

indescribable beauty. For it subtly combines mass with harmony of proportions, having

neither excess nor deficiency, as it is both more pompous than the other buildings we

are accustomed to and much more decorous than those which are huge beyond

measure and abounds exceedingly in sunlight and gleaming reflections. Indeed one

might say that its interior is lit not by the sun from without but by a radiance generated

within, such is the abundance of light that bathes this shrine all round.

! Prince Vladimir of Kiev spoke on a service he attended: “We knew not whether

we were in heaven or non earth. For on earth there is no such splendor or such beauty,

and we are at a loss how to describe it. We only know that god dwells there among

men, and their service is fairer than the ceremonies of other nations. For we cannot

forget that beauty.”

!

! The ambitious scale and avant-garde design was evident as soon as the initial

work on the primary structural piers had started. These were to carry the vaults for the

nave, the clear spanning significantly greater than the closest comparable structure in

Rome - The Basilica Nova of Maxentius and Constantine, built two centuries earlier.

Perhaps more impressive, was the sheer speed in which the construction occurred. Six

years was all it took between the destructive fire and the church’s first dedication.

! The first rebuilding was due to a fire after St John Chrysostom was banished.

The church was restored and established under Theodosius II. However, the Nike riot of

January 532 sparked yet another flame which almost killed Justinian himself. However,

all these factors set up the perfect stage for a church that would emanate an

unprecedented splendor.

! The Ottomans had made their presence felt through many mediums including

architecture, and it was no different in this case. After 20 years of serving the functions

of a church. Hagia Sophia was converted into and used as the Mosque of Aya Sophia.

Externally the silhouette changed after the the tall permanent minarets in the four

corners were added. The old patriarchal palace and other Byzantine structures were

demolished transforming the surroundings. Aya Sophia’s external appearance was

altered as further structural repairs were undertaken such as the fresh additions to the

external buttresses.

! This continued until secularization in 1934 by Ataturk. The following year marked

the opening of the building as a museum, terminating fourteen hundred years of use as

a place of worship by three different faiths - Orthodox, Catholic and Muslim.

Now & Then

! Still dominating it’s context with authority today, this building’s function has

transformed over time from its initial establishment Justinian’s Church into the Mosque

of Aya Sofia until it’s final conversion into a museum after secularization in 1935. Its

series of reconstructions and repurposing has resulted in a loss of the original

atmosphere and exact knowledge on how the construction process commenced.

! The chief contrasting elements are the strong buttressing arms that project from

the North and South sides of the dome base.

! The cluster of semi domes are repeated from east two west with two differences.

First was the largest single window which replaces a small central semidome. Another

one of these domes was constructed flatter at the top. These divides occurred due to

the rebuilding of these semi domes at independent dates. The distinct form is not as

comprehensible as the church is viewed from a closer distance. This is a result of the

outer buttresses on all sides that were built at a later date.

! Up close, clear evidence can be seen of original entrances existing on all sides.

Only two of these, the less direct western entrances are being used today. Nearby, there

are various Turkish tombs and the baptistry in an enclosed garden to the south. Several

workshops and other buildings are located in a similar space to the north behind a

higher wall.

!

! Upon entrance, the dome is hardly seen. The eye is then magnetically pulled up

to the brilliance of light rays pouring through the windows. The movement complimented

with the movement created by the semi domes, arches and pendentives. The ribs

between the windows diminishing as they reach towards the crown. An even larger

circular plaque with arabic calligraphy overlays the center of a gold mosaic.

! What is perhaps most impressive is the aura or character that the space projects.

Many would argue that the Pantheon was the nearest comparable space when it came

to experience. However, what makes Hagia Sophia stand out is the subtlety and sheer

complexity that would leave the users of the space in awe. ‘Hagia Sophia combines the

centrality of a dome with the axiality typical of a normal basilica, and its true boundaries

are elusive. They alternately advance and recede, sometimes solid though faced in

insubstantial-looking marble, and sometimes not more than open screens. Never being

fully visible at one time, they appear continuously to change as one moves around, and

there are ever-changing partial glimpses of the peripheral spaces of aisles and

galleries.’

! An underlying geometric discipline creates a sense of harmony between the

elements. This is apparent in the domes and semi domes. The effect was also

influenced at a micro scale through the details such as the horizontal cornices that

travel across the piers and over the colonnades. There is a sense of mystery between

the possible relationships between the surfaces and the structural colonnades and

arcades who’s function is clear. The way the decoration on the ends of the arcades

moves through to the wall, it terminates simply without a suggestion of the follow

through of forces that carry through the columns, pilasters or piers.

!

!

Design & Reconstruction

! A precedent and stimulus for the inception of the church in 527 would be a

variant of the rectangular timber-roofed basilica such as St Peter in Rome and the

Anastasis basilica in Jerusalem. The process of construction in precedents was of use

due to the fact the plan allows: accommodation large congregations, and an ease of

construction; not to mention the distance from the Pagan connotations of a temple.

Another notable mention would be San Lorenzo in Milan that was built in a monumental

manner to help solidify Milan’s stance as capital of the West. It’s central space was

based on a square and roofed by a groin vault.

! The final straw was pulled when Justinian started his rule, he called for a

structure that would ‘surpass all others in beauty’. He anticipated the value of replacing

the Theodosian church with something that would draw on the powers of the Golden

Octagon and its successors, conveniently aligned with his values and visions of the

future.

! There must have been a plenitude of problems during the development of the

design that proposed something at an unprecedented scale. Particularly with the

construction of the high arches and vaults while maintaining a stability of the whole.

There were also constraints in relation to the size of the monolithic blocks that they

could acquire.

! The architects were limited without the analytic ability and techniques in various

stages of the design. Stability must have been an earlier one, as well as the

maintenance of this stability over the whole construction process. As resources

diminish, the structural implications of the scale would be apparent. Earthquakes were a

major cause of collapse as it created vertical and lateral fluctuations that would be

loaded at the piers.

! Three major Byzantine reconstructions were documented, each involving part or

all of the dome. The dome first collapsed after the effects of an earthquake. The dome

was rebuilt to a raised profile, requiring he reconstruction of the main arches and

pendentives. The next two collapses had many likenesses. These occurred on the 26th

of October in 989 and the 19th of May, 1346, which caused the collapse of the west and

east sections of the dome respectively.

Structural Analysis

! It is hard to accurately make conclusions on the structural and material qualities

as time has taken its toll on the building’s exterior face. Records recovered from the

past have proven inadequate at portraying what was seen in the past. Even less can be

deduced about the physical properties of the materials, which is vital for many types of

structural analysis.

! The main elements of the structure are constructed from stone, bricks and

mortar. Iron and timber was also used to a lesser extent.

! Stone is used mainly in the piers. Either limestone or a local granite, and

sometimes paired. Made to fit tightly, they averaged at 0.45m in depth, with some

blocks surpassing a meter in length. The marble columns in the nave, isles and galleries

make up the remaining use of stone in the structure. Most of these columns are

monolithic, set up against the stone to minimize the risk of failure due to the uneven

distribution of pressure. Other ways to minimize the risk of buckling included using

bronze collars at the head and foot of the columns.

! The monolithic columns are the only structural element whose function is clearly

expressed. The arches are found with two diameters, 1.2m and 1.6m. The upper and

thinner columns move the vertical loads from above through to the lower gallery

columns. Although it hasn’t been confirmed, those are thought to be made of brick.

There are a few examples of columns that are different. Some are due to the rebuilding

at time periods.

! Barrel vaults are found on the east and west that span between the secondary

piers. Like the ones over the nave, these were most likely constructed in concentric

rings out of brick. As the thickness was only one brick, fills were used over the shells for

stability.

! Little is known about the construction method of the four pendentives. A theory is

that they were constructed in a parallel way to the semi domes, through the preliminary

use of an inner skin.

! Spanning over the tops of the pendentives is the main central dome. In reality, it

does not as appear as uninterrupted or sound structurally as it does on the exterior.

They are constructed with brick laid slightly flatter than the center of the dome’s

curvature. Thin slabs of marble were used as springers for the window frames. There

are low ‘breast-walls’ beneath these windows which signify the start of a continuos

surface on the exterior of the dome. Anticipating a smooth surface for the mosaic, the

angle of the web’s ribs decline before reaching the crown. Timber ties were used at the

arches during construction of the ribs.

! The structural system can be understood as a primary system assisted by

several secondary systems. The primary system consists of: the central dome and

vaults over the nave; the main piers supporting these two elements; the secondary and

buttress piers; and the arches that spanned between these piers. All other structural

elements can be defined as the secondary system. This includes the arches and vaults

in the narthexes, as well as the aisles and galleries. This includes the tympana, located

between the main North and South arches and the access ramps. Colonnades are

abundant and play a part in both systems. Another feature are the brick vaults which are

underpinned, and their interconnections stiffened, by lower and deeper bracing arches

of stone spanning between the connections.

! The original outer walls were also constructed out of brick. Inspecting the plan of

these walls displays a consideration of the hierarchies of the structural systems.

! There is a complex system of iron ties to aid in the resistance of outward thrust of

the vaults. These ties were anchored visibly through pins at the end. These ties are

located in: the centre bays; the vaults in the aisles and galleries; and beneath the

marble slabs of the galleries.

! The tympana were also made out of brick. These decrease in thickness towards

the apex, a reflection of shifting form of the inner frame.

! The geometry of the domes is in part due to the mathematical ability of its

designers, they had trouble explaining what a semi-dome was. The spherical geometry

was a resultant of construction and performance as well as drawing itself. Internal

forces acting equally. Form and layout and materials correspond to the magnitude and

forces flowing through it. Even though it was apparent the architect had trouble

explaining how a dome works exactly, by anticipating the flow of forces in a dome, there

was a repetition of this technique at different scales.

! The present dome consists of two sections at the North and South that have

stood since the initial reconstruction. The west was a result of the second reconstruction

and the third reconstruction dictates the form of the eastern portion. These are apparent

on both the interior and exterior as deformations of the continuos surface.

! The attention paid to detail of the reconstruction implies a strong intention to

avoid the same failure at first, however cost and efficiency were both factors during the

latter process.

Appendix: Illustrations

Vaulting the nave through the use of a ground vault

over a central square.

A theory on how the nave wall vaulted using

squinches that bridged the corners of the central

square.

A possible final development of vaulting the central

square using a dome on merging pendentives.

Thrust forces are shown as arrows and the radial cracking is presented as dashed lines

after the completion of the dome.

Bibliography

Mainstone, Rowland. Hagia Sophia: Architecture, Structure and Liturgy of Justinian’s

Great Church. Hungary: Pauline Baines. 1988. Print.!

Nelson, Robert. Hagia Sophia, 1850-1950: Holy Wisdom Modern Monument. 1947.

Print.

Wenzel, Fritz. "Investigations into the Construction and Repair History of the Hagia

Sophia." Construction History 25 (2010): 1-20. Web. 26 Mar. 2015.

"A Monumental Struggle to Preserve Hagia Sophia." Smithsonian. N.p., n.d. Web. 23

Apr. 2015.

"Hagia Sophia." Wikipedia. Wikimedia Foundation, n.d. Web. 23 Apr. 2015.