CRITICAL ANALYSIS OF THE FIRST BOSPORUS BRIDGE,

ISTANBUL, TURKEY

Matthew Smith1

1University of Bath

Abstract: This paper presents a critical analysis of the First Bosporus Bridge. The bridge crosses the Bosporus

Straits, uniting the two banks of Istanbul with a road crossing for the first time. The bridge was completed in

1973 and has a main span of 1074 m. This paper considers aspects of aesthetics, loading, strength, construction

and future requirements.

Keywords: Istanbul, Bosporus, Suspension Bridge, Aerodynamic Deck, Steel,

Fig 1.1 Elevation of the First Bosporus Bridge at night showing the coloured lighting [4]

1 Introduction

The First Bosporus Bridge is a steel suspension

bridge located in Istanbul, Turkey. The bridge is a well

used road bridge that has had a significant effect on

Istanbul [3].

Until the construction of the First Bosporus Bridge

there was no dry crossing between the European and

Asian sections of Istanbul. All transport between the main

city on the Europeans side and the suburbs on the Asian

side was done by boat, creating huge queues [3] at rush

hours effectively costing the country millions.

The First Bosporus Bridge was designed by Freeman

Fox & Partners, also responsible for the Severn Bridge

and the Humber Bridge and the similarity is visible in all

sections of design.

The design life of the bridge is likely to have been

100 years because the durability and cost of the materials

is relatively high as is the future requirement for a

crossing of the straits. The bridge has been in operation

for 36 years and has not encountered any serious

problems. The success of bridges designed in similar

ways by the same company inspires confidence that this

bridge will remain operational until the end of the design

life.

The bridge is more than just a way of getting from

one side of the straits to the other. It has become a tourist

attraction in its own right. During the night the bridge is

illuminated in coloured light [Fig. 1.1] (different colours

on different nights).

Freeman Fox & Partners were famous for their use of

an aerodynamic deck to produce long-spanning

suspension bridges. The Tacoma Narrows disaster of 1940

Proceedings of Bridge Engineering 2 Conference 2009 April 2009, University of Bath, Bath, UK

prompted the deck design to become very heavy to reduce

the effect of the wind however Freeman Fox & Partners

did not follow this trend in their bridges, giving the

elegant deck seen above and on the First Severn Crossing.

The bridge cost £15M in 1973; it was funded partly

by the Turkish government and partly by a European

Investment bank, backed by several European

governments and the EEC. To recoup the money spent on

the bridge a toll was (and still is) required to cross.

2 Aesthetics

2.1 Introduction

To better analyse the aesthetics of a bridge the 10

points set out in F. Leonhardt’s book ‘Bridges’ should be

considered [1][6]. These 10 points cover the main areas

which affect the aesthetics of a bridge and are used by the

majority of designers as a guideline to producing beautiful

bridges. These points are:

1. Fulfilment of Function

2. Proportions

3. Order

4. Refinement of Design

5. Integration into the Environment

6. Surface Texture

7. Colour of Components

8. Character

9. Complexity in Variety

10. Incorporation of Nature

It is not necessary for a bridge to comply with all 10

points to be considered beautiful as many are subjective,

especially character.

2.2 Analysis

2.2.1 Fulfillment of Function

The function of the bridge can be clearly seen as a

highway suspension bridge supported by the cables which

hang between the towers. The function is made more

obvious by the thin aerodynamic deck that could not act

as a beam.

2.2.2Proportions

The bridge has a very large span and a thin deck

giving it a very slender look in elevation. The towers are

large and bold, therefore compliment the thin deck. The

proportions of the approach viaducts on either side of the

main suspension bridge are less desirable as the supports

look too slender, especially in contrast to the large tower.

In general the proportions of this bridge are very good as

with all of the Freeman Fox bridges.

2.2.3Order

The Order of the bridge is very good as the entire

deck is uniform and the spacing between the hangers is

also uniform. The approach viaducts have a thicker deck,

as this section is a multi span beam bridge; however this

change occurs in the tower and does not negatively affect

the aesthetics. The absence of cables from the approach

viaduct has a negative influence on the order.

2.2.4Refinement of design

The towers are tapered in the tradition of the Greeks

which improves the aesthetics of the bridge [9]. Although

done for structural efficiency the zigzag hangers and the

aerodynamic deck are refinements that are very pleasing

aesthetically. The choice to conceal all changes in deck

depth to the tower makes the change less obvious and

therefore a useful refinement.

2.2.5 Integration into the Environment

The local environment is urban on both sides of the

straits and therefore a modern bridge, constructed using

metal, fits well into the surroundings. The tall towers and

sweeping cables fit well rolling hills and large expanse of

water.

2.2.6 Surface Texture

The deck of this bridge is a smoother texture than the

tower which is widely recognized as a good aesthetic

choice [9]. The deck is not so smooth to be shiny but

combined with its slenderness works well with the

surroundings giving the hint of a reflection of the water

without looking too unnatural.

2.2.7 Colour of Components

The dark colour of the towers, cables and deck work

very well with the surrounding area and makes the

hangers seem almost invisible during the day. There is

nothing particularly impressive with the colouring until

the night when the bridge is illuminated in a variety of

different colours, Red and Purple work to the greatest

extent giving a modern, sleek and attractive look to a 35

year old bridge. One reason for the effectiveness of the

lighting is the integration into the structure, giving the

lighting a less forced feel [7]. Despite being an old bridge

it is well maintained and has not been too badly affected

through discolouring as some bridges are.

2.2.8 Character

There is nothing about this bridge that gives it great

character, in its structural system it is a simple suspension

bridge and blends well enough into the cityscape during

the day to mean it does not require character. During the

night however, the coloured lighting makes it into an

interesting and attractive bridge that does have character.

2.2.9 Complexity in Variety

Being a suspension bridge there is little that can be

added structurally and so anything extra would be solely

to add complexity and would ruin the functionality and

order of the bridge. This bridge works well in its

simplicity.

2.2.10 Incorporation of Nature

The First Bosporus Bridge does not relate to nature

any more than any other bridge and does not need to; it is

situated in the middle of a city and is above a busy trade

lane, it is likely that to try to incorporate nature into this

design would make it look out of place and absurd.

2.3 Summary of Aesthetics

In the key areas of aesthetics this bridge succeeds, it

is a simple and elegant bridge that exhibits the structure

clearly. The change in colour of the bridge between day

and night is almost like the bridge is changing its mood

and because of this, the character changes as well, from

the calm functionality of the day to the vibrant excitement

of the night. It is because of the bridges performance in

these points that it is a well placed and beautiful bridge.

To the lay person the curve of the cable improves the

aesthetics of the bridge [7] which may be another reason

for its success amongst the local people of Istanbul.

3 Dimensions

3.1 Introduction

This information has been taken from The Bosporus

Bridge [3] or assumed.

3.2 Deck

The cross section below [Fig 3.1] shows the

dimension of the deck.

Fig 3.1 A cross section of the deck, dimensions in mm [3]

3.3 Towers

Both towers stand on two legs, each with their own

piers. The European side uses round piers with a diameter

of 18 m and begin at 17 m and 24 m below sea level. The

Turkish side however uses rectangular piers of 15 m x 19

m, beginning at just 5 m and 10 m respectively below sea

level. The reason for this difference is the difference in

soil materials on either side. The first 10 m of European

soil is too soft to support the huge structure of the bridge.

The towers are 165 m high have the rectangular plan

of 7 m by 5.3 m at the base. The towers are tapered from

5.3 m to 3.0 m at the top (viewed from the bridge). The

towers are connected by three horizontal members to

increase lateral stability. The cross section below [Fig.

3.2] shows the dimensions of the towers.

Fig 3.2 Cross section of the tower, dimensions in mm [3]

3 Loading

3.1 Introduction

Determining the loading on a bridge is a key part of

design and is well documented in BS 5400-2:2006 [2].

The major loading can be split into dead, super-imposed

dead, traffic, wind and temperature. This bridge was

designed with the intention of being a lightweight and

aerodynamic bridge to counter the large wind loads that

suspension bridges take. To carry out some rough

calculations into the efficiency of the bridge the loadings

on the main span will be estimated.

3.2 Dead Loads

The dead loading includes all the structure of the

bridge and is always present during operation. The dead

loads are known values and should not be subject to

change and therefore a lower factor of safety is required.

The dead loading (unfactored) on the First Bosporus

Bridge can be estimated as follows:

Steel Deck 299 kN/m

Steel Cable 69.9 kN/m

Steel Hangers 1.0 kN/m

3.3 Super-Imposed Dead Loads

The super-imposed dead loads include all non-

structural permanent loading. These have higher factors of

safety due to the greater uncertainty in the materials and

the possibility of replacements being heavier than the

originals as the design life of these materials is lower than

the permanent structure. Below are estimations for the

main types of super-imposed dead loads (unfactored).

Mastic Surface 22.6 kN/m

Handrails 2.0 kN/m

Services and Finishings 2.0 kN/m

3.4 Traffic Loads

The main live loads that the bridge must withstand

are primarily vehicle loading as this is a road bridge.

There are many load combinations which need to be

analysed to get the most onerous cases of stress in the

bridge, both hogging and sagging must be investigated.

Vehicle loads can be split into HA and HB loading.

HA loading is a uniformly distributed load (UDL)

acting over a notional lane in conjunction with a knife-

edge load (KEL). HA loading is the design loading for

heavy fast-moving traffic including bouncing factors [6].

Figure 10 and Table 13 of [2] are used to get the nominal

value for the UDL per lane of 18 kN/m. The KEL is taken

as 120 kN per notional lane (both unfactored) The HA

loading is taken over two lanes and then 1/3 of HA is

taken over all additional lanes to give the worst case

scenario. The First Bosporus Bridge has 4 notional lanes

on each side of the central reservation.

HB loading accounts for abnormal truck loading. The

unfactored load is taken as 10kN per axle per unit, with

the maximum number of units being 45 [2][6]. HB

loading is used together with HA loading to create several

load cases which should all be investigated.

There are also secondary traffic loads which should

be considered on any highway bridge, these include

longitudinal forces from acceleration or braking, taken as

8 kN/m along a single notional lane [2][6]. Collision

loading on the parapets equal to 25 units of HB loading

and accidental skidding which can be modelled as a point

load of 250 kN acting horizontally [6].

Fatigue loading is also linked with traffic loading and

requires consideration. BS 5400-10:1980 is a guideline to

fatigue checks [6].

3.5 Wind Loads

Suspension bridges are very badly affected by wind

loading because large spans and minimal lateral

resistance. It is not just the horizontal force which can

damage the bridge; wind could trigger the bridge to

vibrate at its natural frequency, leading to severe damage

and collapse as demonstrated in during the Tacoma

Narrows disaster of 1940.

To combat the effects of wind loading on the First

Bosporus Bridge, an aerodynamic deck was designed

which reduces the wind loading. In addition to the

aerodynamic deck the hangers are inclined in a zigzag

pattern which gives extra lateral stability. The estimated

wind loading acting on the bridge is taken from [2]

section 5.3.

The aerodynamic deck of this bridge sets it apart

from many other bridges of the time (especially in USA)

which, to combat the effects of natural frequency and

coupling use far heavier decks which generally detracts

from the structural efficiency, cost efficiency and

aesthetics

3.6 Temperature Loads

Temperature loading can be very detrimental to the

life of a bridge of this size. A change in temperature will

result in an expansion of the bridge and without

expansion joints a stress would be induced. The First

Bosporus Bridge uses ‘rolling leaf’ expansion joints

which need to be well maintained and kept free of

blockages to avoid the induction of stresses in the bridge.

The temperature on the bottom of the bridge is likely

to be far lower than the temperature on the top on a sunny

day, creating differential expansion which is far more

damaging.

3.7 Earthquake Loads

The First Bosporus Bridge is located in an earthquake

zone and therefore must be able to survive an earthquake.

The movement joints help to alleviate some of the forces

which the deck would experience in an earthquake.

4 Structure

4.1 Introduction

This section aims to replicate the calculations that

would have been completed in the design stage. They are

simplified calculations that focus on the major details of

the design using approximate values estimated in section

3. These calculations are based on BS 5400-3:2000[5].

The load from the deck is carried through the hangers

into the cable which pass the load into the tower and the

anchorage. All loading on the approach viaduct is taken

by the columns.

To be sure that the bridge is able to withstand the

most onerous bending moments numerous load cases

need to be looked at. A fully loaded bridge does not

necessarily give the most onerous case.

All bridges designed to BS 5400 must be checked in

both ultimate limit state (ULS) and serviceability limit

state (SLS). The factors given in Table 1 of BS 5400-

2:2006 [2] are different for ULS and SLS, with ULS

being greater.

4.2 Ultimate Limit State of Bridge Components

4.2.1 Hangers

The hangers are subjected to the dead, super-imposed

dead and live loading from the deck as well as their own

self weight. Each pair of hangers supports one 18 m

section of deck and 4 nominal lanes. The highest possible

live load is given by HA loading, full in two lanes and

one third in the other two lanes. The diameter of the

hangers has been assumed to be 150 mm, T460 grade

steel and γm = 1.15 this gives σdesign = 400 N/mm2

Fig 4.1 Diagram showing factored loading and

maximum force in hangers

� = �/� σ = 3.74 x 106 / (π x 752) σ = 211 N/mm2 < 400 N/mm2

This should give the required redundancy in case one

hanger requires replacement.

4.2.2 Cables

The huge cables must take all the loading from the

deck as well as the self weight from the hangers and itself.

The angle between the horizontal and the cable at the

tower is 17° and the diameter of the cable is 760 mm as

explained in section 5.4. The tensile strength of the cables

is 160 kg/mm2 [3].

(1)

Fig 4.2 Diagram showing the factored loading on the

entire cable

Fig 4.3 A free body diagram at the cable-tower

connection

� = �/� σ = 606 x 106 / (π x 3802) σ = 1371 N/mm2 < 1569 N/mm2

4.3 Wind

[2][6]

�� = �������

vc is the basic wind speed which has been estimated

to be 25 m/s. This is a conservative estimate. K1 is the

wind coefficient, which equals 1.55. S1 is the funnelling

factor which, because of the low lying land surrounding

the bridge which makes funnelling very unlikely, is taken

as 1.00. S2 is the gust factor which at 64 m is 1.37 [2][6].

�� = ! × �. !! × �. ## × �. $% = !$. � &/'

This value can be converted in to a horizontal force

based on the exposed area of the bridge. It does not

account for the aerodynamic reduction [6] which this deck

would give, therefore it is conservative.

Clause 5.3.3 [2][6]

() = *+�,-

q is the dynamic pressure head is equal to 0.613vc2

[6]. A1 is the area of the bridge which faces the wind. CD

is the coefficient of drag which is taken from [2] as a

function of the b/d ratio. From figure 5 of [2] CD can be

taken as 1.2.

() = #. .�$ × !$. � × �#%/ × $ × �. = .. .0 12

The vertical force can also be calculated using similar

formula.

Clause 5.3.5[2]

(� = *+$,3

A3 is the area in plan and CL is the coefficient of lift

which can be found from figure 6 of [2]. Assuming α =

10° CL is equal to be 0.79

(� = #. .�$ × !$. � × �#%/ × �0 × #. %4= .. $ 12

This is a beneficial load and therefore has a factor of

1.00 whereas the horizontal load requires a factor of 1.40

if considered with dead load only and 1.10 which used in

conjunction with other loading conditions.

The factored Pt load (as a secondary loading

condition).

.. .0 × �. �# = %. !� 12

4.4 Temperature

The steel deck has a coefficient of thermal expansion

of 12 x 10-6

/K. Assuming an increase in temperature of

25 K. ∆3 = 3∆67 ∆3 = �#%/ × ! × � × �#8. = #. $ &

This change in length is acceptable and will be

negated by the expansion joints. The stress induced in the

deck should the expansion joint fail to work because of

blockage or poor maintenance is calculated in equation 6.

9 = :; = ∆33 ;

9 = #. $ �#%/ × ## × �#$ = .# 2/&&

This stress must be factored using the loading factors

taken from Table 1 [2]. γF3 = 1.30

9 = .# × �. $# = %0 2/&&

This stress is acceptable and below the capacity of

the steel.

4.5 Natural Frequency

Using the Rayleigh-Ritz equation the natural

frequency of the bridge can be estimated. This value

should be above 5 Hz in the vertical direction while

unloaded [6].

<= = (>?@)AB CDEFG

(Βnl)2 is 22.37 for this case. E is the young’s modulus of steel, 200000000 kN/m2. I is the second moment of area which has been calculated as 24.4 m4. m is the mass density per unit length of the section at mid span. For the horizontal case dead and super-imposed dead loads only are included giving 72600 kg/m. l is the length of the deck, which is 33.4 m <= = 22.37 e200000000 × 24.472600 × 33.4f

<= = 22.37 × 0.23 = 5.19 gh

(2)

(3)

(4)

(5)

(7)

(6)

This value is acceptable falling above the 5 Hz limit

stated above and below the 75 Hz that if exceeded is

uncomfortable.

4.6 Load Cases

The most onerous situation is not necessarily the

highest loading and designers must consider many

different load cases to be sure that the bridge is suitable.

Designers must consider temperature, traffic, wind and

dead loads all acting together however to counter the fact

that this unlikely BS 5400 lowers the factors of safety on

the secondary live loading. This section contains a few of

the load cases that will have been considered in design.

4.6.1 Load Case 1

The load case depicted in [Fig. 4.4] is designed to

give the maximum sagging moment.

Fig 4.4 A drawing showing simplistically the positioning

of the primary traffic loads and a moment diagram

4.6.2Load Case 2

This load case is an attempt to find the greatest

hogging moment in the deck. The factor of the live traffic

loads have been reduced to 1.30 for both HA and HB in

accordance with [2].

Fig 4.5 A drawing showing simplistically the positioning

of the primary traffic loads and a moment diagram

4.7 Foundations

The European side substructure is founded on

contorted mudstone or schistose rocks of the Upper

Devonian age [3]. The rock strata have undergone a large

amount of folding and it is very difficult to predict the

type and strength as the orientation changes every few

metres. These folds have also lead to the rock becoming

fractured and soft, in particular underneath the anchorages

[3]. The unpredictability and the softness of the rock

mean that the excavations on the Europeans side are far

greater than those on the Asian side where the bedrock is

limestone [3].

5 Construction

5.1 Introduction

Bridge construction is unlike almost all other types of

construction because there is no firm place to rest

machinery and plant cranes. In the case of the First

Bosporus Bridge barges were used to put the deck into

position. The towers were constructed first, followed by

the cables and then the deck, connected to the hangers in

stages, starting in the centre and working out towards the

towers. Much of the information for this section was

gathered from [3] The Bosporus Bridge, Sheridan Group.

5.2 Foundations and Anchorages

The cables carry large horizontal loads and this must

be transferred into the ground at a point behind the tower.

The anchorages on each end take a 15400 tonnes per

cable [3] which is a huge force and requires significant

foundations. It is important that these are situated in a

position where the ground has good geotechnical

properties. When the cables reach the anchorages they

splay into their separate strands, each of which is

connected into a shoe which is bolted with steel slabs into

the prestressed concrete anchor slabs. The trenches (up to

28 m deep) are stepped [Fig. 5.3] and crosswalls are

constructed [Fig. 5.4] to increase the sliding resistance.

The Ortakoy (European) anchorage contains 60000

tonnes of concrete as a counter load to the cable force.

The Beylerbeyi (Asian) side anchorage contains 50000

tonnes [3] of concrete which gives a factor of safety for

the anchorages of over 3 in both cases.

Fig. 5.1 The anchorage block during construction [3]

Fig. 5.2 The anchorage during construction showing the

cables [3]

Fig. 5.3 (Right) One side of an anchorage after

excavation, showing the trenched system [3]

Fig. 5.4 (left) The same side of an anchorage during

construction, the crosswalls are almost complete [3]

Fig. 5.6 The connection between the anchorage and the

cable showing the reinforcement [3]

The piers for the towers were excavated into the

bedrock to get a firm footing. The soil conditions on the

European side of the bridge are far worse than the Asian

side. The European side required steel cofferdams to be

constructed to exclude the water while removing the soft

soil. All piers are close to the edge of the water to reduce

the span as much as possible.

Fig. 5.7 One pier on the European side ready for insertion

of the pre-fabricated tower [3]

5.3 Towers

The hollow rectangular cross sections of the legs

were constructed in Italy and were preassembled on

arrival in Turkey. This was considered the best method of

construction because of the added control the contractors

had over the situation, the tolerances of the straightness of

the tower were very low and no allowance for inaccuracy

in erection was made. The small margin for error which

the designers required meant that the greatest care had to

be taken when assembling and erecting the lowest section

of the towers [3].

Climbing cranes were required to lift each section’s

four panels into position [Fig. 5.8]. The crane started at

the bottom and worked up, connecting each panel to the

one below. Grip bolts and tension bolts have been used to

hold these in place.

Fig 5.8 A tower under construction showing the climbing

cranes at the top [3]

Fig 5.9 The inside of one leg of the tower showing the

extensive steelwork [3]

5.4 Cables

The main cables have been formed through spinning

parallel-wires which is common to most suspension

bridges. This method was chosen over pre-formed

parallel-wire strands. The cables are made up of 19

strands of 550 wires, each with a diameter of 5mm. The

resulting main cable has a finished diameter of 760mm

after the spinning process.

Fig 5.10 The beginning of the spinning process showing

one strand of 550 wires [3]

Fig 5.11 The process continues, joining strands [3]

Fig 5.12 A hydraulic compacter is used to give the cable a

circular shape [3]

Fig 5.13 The completed and loaded cable gets coated in

red lead paste for protection [3]

To put the wires into position two catwalks had to be

erected from the anchorages, through the towers,

following the proposed route of the cables, when the

cables were being lifted into position the Bosporus

shipping lane to be closed.

The hangers are then fixed to the cables using two

semi-cylindrical steel casings. These are then clamped

into place. To protect the wires from corrosion the cables

are coated in red lead paste and wrapped in a protective

casing of galvanised annealed steel wire once the full

dead load was attached.

5.5 Deck

The deck was attached to the hangers in sections,

starting in the centre. These sections consist of 18 m

length of the deck prefabricated 2 miles north of the

bridge in Göksu. Stiffened steel panels, typically 18 m by

2.5 m are used, imported from England or Italy and

assembled using automatic welding machines.

As with the towers the allowable inaccuracies were

small and therefore it was important that the deck boxes

fitted together perfectly. To achieve this each box was

assembled next to the box that it would be next to during

operation.

Barges were used to transport the completed box

units. As mentioned previously the centre section was the

first to be attached and then the boxes to either side of that

were attached simultaneously. Once a box had been

attached to the hangers it was temporarily bolted to the

adjacent box. This was designed to incorporate a lagging

procedure which harnessed the changing profile of the

bridge (especially the joint) while other boxes were being

connected. The final connection was made using welds.

Fig 5.15 The centre section is lifted into place [3]

Fig 5.16 The box units under construction [3]

The 40mm thick mastic surface which the vehicles

would travel over was put down along the carriageway

once the welding was complete. The super-imposed dead

loads such as barriers and lampposts were attached

afterwards.

At the join between the deck, approach viaduct and

tower there is an expansion joint on both sides of the main

span. A ‘rolling leaf’ style joint was used [3]. The

expansion joint is not just to alleviate temperature induced

stresses in the structure but also acts to absorb earthquake

movement.

Fig 5.17 A ‘rolling leaf’ expansion joint [3]

Fig 5.14 The

sections of deck

are independently

lifted off barges

to be put into

position [3]

5.6 Approach Viaducts

The approach viaducts are supported by columns. A

cantilever construction system is used starting at the

anchorages in the direction of the tower. The steeply

sloping sides of the bank mean that floating cranes are

required to bring the boxes into the foot of the tower.

Gantries running up and down the backstays are used to

lift them into their position [3].

Fig 5.18 The Approach Viaduct under construction [3]

Fig 5.19 The finished bridge during the day [3]

6 Future Requirements

6.1 Introduction

It is difficult to predict the usage a bridge will get

especially when there is no method of dry transport and

therefore the Bosporus Bridge was designed to be flexible

in terms of traffic movement. Some lanes are reversed in

peak flow to cope with the demand and extra lanes,

originally for emergency vehicles are sometimes used in

peak traffic. Pedestrians have been prevented from

walking across the bridge making it solely a transport

bridge for vehicles.

The high demand for a road crossing meant that

Freeman Fox & Partners were again commissioned by the

Turkish government to building another road crossing

over the Bosporus, The Fatih Sultan Mehmet Bridge was

completed in 1988 with a similar design to alleviate the

congestion and spread the demand of the First Bosporus

Bridge. Istanbul is the largest city in Turkey and is still

growing. The format of the city, with the suburbs on one

side of the straits and the main city on the other, means

that the demand to cross is increasing. Due to the

increased traffic loading and the age of the bridge it is

unlikely that it would be feasible to expand the existing

bridge short of making the two emergency lanes

permanently for ordinary traffic. Should the demand

increase enough to make crossing the straits very time

consuming it is likely that the Turkish government would

opt to construct another bridge.

7 Conclusion

The First Bosporus Bridge was one of a series of

suspension bridges which has created a new, popular and

effective style of suspension bridge design. The bridge,

after completion, significantly improved the transport

situation in Istanbul [3] by removing the large queues for

ferries that had tainted so many commuters journey.

The bridge is aesthetically pleasing; complying with

many of the rules set out by Leonhardt [1] and continues

to be a spectacle at night becoming a tourist attraction as

well as a transportation device. The Bridge appears to be

well maintained and should continue to serve without

requiring large scale repair for many years to come.

The construction process was quick and relatively

problem free. The methods had been tried on previous

projects (First Severn Crossing) and have, due to their

success, been carried forward onto many more

constructions since.

8 Acknowledgements

This paper could not have been completed without

the assistance of Sian O’Keefe at Hyder Consulting who

has provided vital information.

9 References

[1] Leonhardt F. 1982. Bruecken/Bridges. Deutsche

Verags-Anstalt.

[2] BS 5400-2:2006. British Standards Institute.

[3] The Sheridan Group. The Bosporus Bridge. L. Bell &

Co. Ltd.

[4] Wow Turkey website – Night Photographs

http://wowturkey.com/forum/viewtopic.php?t=4552

&start=120

[5] BS 5400-3:2000. British Standards Institute.

[6] Ibell T. Bridge Engineering. Department of

Architecture and Civil Engineering, University of

Bath

[7] Highways Agency. 1996. The Appearance of Bridges

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The Stationary Office. ISBN 011 5518045.

[8] Ray S.S. Barr J. Clark L. 1996. Bridges – Design for

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[9] Highways Agency. 1998. Design Manual for Roads

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The Stationary Office. ISBN 011 5520287.