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The concept of earthquake preparedness needs to be done before the earthquake , a comprehensive
and the section dealing with long-term studies , in short, " risk management" is called . very
size , laborious , long-term operation since it contains very easy realization
Although it is not very effective in mitigating earthquake hazards can be accomplished
these types of events , an adequate seismic safety of the existing structure to be restored to
event type is one of great importance .

In terms of seismic safety of an existing structure when it comes to strengthening ,
various approaches , various methods and techniques , or even combinations thereof suggested.
In such a case , the most effective, most efficient , optimal strengthening strategy revealed that
to put , in terms of achieving the best results are of great importance . This situation
as well as specific for one , with similar characteristics to a particular set of structures
is valid . Even in a city , a country , a region under similar conditions all
Even an augmentation strategy can be generalized to structures may be mentioned .

Turkey is known to carry a large enough earthquake safety building stock where
are known. They are in and structural characteristics substantially similar
buildings against earthquakes of this stock containing an appropriate strategy for strengthening the monitoring
inappropriate in the framework are briefly investigated . Indeed, in many years , mainly
Middle East Technical University research and practices developed within the framework of
this empowerment strategy is applied broadly in Turkey today . However,
these applications are generally performed without being conscious , so the application
various inaccuracies and omissions are inevitable . The purpose of this paper, there
subject to augmentation strategies , based on the basic principles and validation together with the reasons
to introduce and define furthermore , in practice some of the concepts that are important
Gold is once again drawing .

2 BASIC DATA
Whether just for a single building , whether it be a certain group of buildings with similar characteristics
for , whether it be in a city or in the country for all similar types of buildings
Whether an augmentation strategy determining (i ) that in that building or group of buildings in the common
seen as common problems and weaknesses, (ii) the intended security level or levels
and ( iii) obtained by boosting technology designated by the most effective
and efficient solution approach is necessary to determine in the light of all this data .
Existing building stock in Turkey , a very large extent , hollow brick wall filled with concrete
Frame type structural structure comprises buildings . Therefore , to be developed
for this kind of strategy to strengthen the supporting structure is to be the most appropriate approach .
Turkey in such structures mentioned above for the data in the three main subjects ,
to form the basis for the strategy to be defined , one at a time in the following paragraphs
is being revised .

2.1. Common Problems
Following the earthquake in the last 15 years made ​​many views above
commonly cited type of structure has revealed the weaknesses of the joint . These observations
• Low-rise (1 ~ 2 -fold) of the building , despite being low-skilled , very bad in earthquakes
do not behave ; The quake occurred at higher forces to remain at low levels
Due to earthquake damage or slight damage usually able to dodge ;
• Multi-storey ( > 10 ~ 12 -fold) and construction of buildings designed to take proper care of them to
is illustrated as a result , quite an adequate level of security with an earthquake
and they are usually very large earthquakes do not create problems ;
• Medium height ( 3 ~ 8 times ) the premises they are often poorly engineered products ;
poor materials , poor design and poor construction , as a result of earthquake safety is usually
is insufficient ; The worst behavior in earthquakes occur in this zone that the remaining structure
and therefore the most severe damage and loss of life and property of the biggest that they take place in
reveals.

The worst part, the majority of urban housing and commercial buildings , as defined above,
constitute poor quality mid-rise buildings . Even worse, when this building rubble
is unequivocally migration , stacked on top eight times is transformed into a pile of rubble . because of
great loss of life seen in this group of buildings from earthquakes are primarily responsible . beyond
however , they usually are not economical for tearing down and rebuilding ; since the earthquake
They are made without attention to safety , but for most use and show
significant investments have been made . Therefore, efforts to reduce earthquake damage
of such structures, strengthening holds a very important place .
These types of structures commonly observed in several general categories common flaws and weaknesses
can be collected . To summarize,
• Lateral stiffness failure - these types of structures , mostly in sufficient number , location and
not regulated nature of reinforced concrete shear and vertical loads generally consider
Taking sized column sections is not large enough , earthquakes
avoid excessive lateral displacements under the effects of a lateral extent that
There is no rigidity . In addition , in most cases , especially at the level of the ground floor ,
soft or weak storey floor are faced with the problem .
• Poor reinforcement arrangement - the reinforcement of beams and columns to be regulated , especially
attention because it is very inconvenient in terms of earthquake resistance and behavior
with insufficient wrapping , inadequate engagement , reinforcement combination of problems such as inadequate
is encountered in almost all the structures in this category .
• Defective design - Design sloppy and often unconsciously performed such
structure , horizontal and vertical irregularities , short column, soft coat , strong beam - weak
The combination of column types are widely available as objectionable regulations .
• Poor concrete and poor workmanship - Very low-quality concrete use of the common problems
is another. This type of structure is very low in the labor generally ; plaster all
It is assumed that hide defects in workmanship .
2.2. Security Levels
In referring to the seismic safety of a building , " is or is not safe against earthquakes "
As a superficial expression is extremely poor . Indeed, said the earthquake , which is the earthquake ;
a small earthquakesensed several times each year , a large earthquake a century
ora disaster so far unheard of ? On the other hand , what is safe ; most
Even without symptoms continue to usea small , repairable damage to a standing
Do you stay or heavily damaged irreparably level but standing without collapsing
and ensure the survival of the people who stay in me ? Until recently
round uncertain words come to be expressed in such manner earthquake safety in recent years,
introduced the "security level or performance level" with the concept a little more meaningful
has been defined in a format . Security levels are generally adopted :
• remain in use - when it is prescribed in the Regulations of the design earthquake ,
Make a lot of earthquake damage or slight damage overcame trouble- use
sending status
• Immediate use - Structure of the design earthquake and a slight damage to circumvent security
After assessment can make use status reopened
• Life safety - Design as a result of the earthquake , repaired structure in nature , no deaths
to cause injury or damage caused moderate in nature condition
• prevention of immigrants - lead to the loss of the structure heavy enough to completely
Staying afloat despite the damage from the collapse of the structure does not result in loss of life condition
Security levels , as well as a defined fumble instead of a single design earthquake ,
By defining multiple design earthquake to choose one of them according to the conditions of understanding
is developing . For example, in the work of revision of the earthquake regulations , general basic
The design earthquake considered in addition to , greater than one smaller than the other two designs
earthquake are mentioned . This defines the following:
• Standard - One in the region of up to 10 % more likely to happen in 50 years earthquake
• The larger - up to 2 % more likely to happen in 50 years earthquake
• Smaller - up to 50 % more likely to happen in 50 years earthquake
2.3. Retrofit Technology
Structure type commonly found in turkey and weaknesses of such structures partners
had briefly referred to above . Said concrete structure of the kind of earthquake safety of
such structures in order to improve reinforcement techniques can be applied to the following
are briefly summarized in the paragraphs and collectively .
Reinforcement techniques , (ii ) strengthening elements ( carrier turns out to be insufficient
The technique applied to the individual elements ), and ( ii) system behavior improvement
( insufficient load bearing elements of the carrier system by changing the general character of the earthquake
Recovering from the effects ) under the heading , under two general categories to assess
are suitable.
2.3.1. Staff Empowerment
a. Empowerment column
The main techniques commonly used are listed below , each effective and useful
where there are short notes are indicated by :
• Concrete mantle - a new well-equipped concrete layer around an existing column
grow by adding column sections . Increase thrust load capacity of the column in
These techniques are very effective , in order to increase the bending capacity possible to use
While there is very cumbersome. Coats ends of longitudinal reinforcement old concrete
be clamped securely enough to the elements and moments at the ends of the column
be brought into position to enable transmission requires very complex processes . good
Equipped concrete mantle , and the old column bandaged , and the shear strength
Increasing the size of both insufficient engagement is effective in solving the problem .
 
 
• Steel mantle - four steel columns at the four corners of the bottom bracket and placing them
compressing the load on the upper base plate and gussets welded provide
with horizontal steel belt bind tightly to each . And thus making an easy and clean
It is very convenient . Is very effective in increasing the capacity of the column axial this technique ,
is not conducive to capacity in terms of bending . Indeed, the lower and upper columns
To ensure continuity if not impossible , difficult and efficiency that are close to it
is questionable . Compressed to very good condition , horizontal belts and shear strength
colon may contribute to the coiled
• Polyester Fibre wrapping - rounded corners, a little of column -like carbon and
bandaged with strips of polyester fiber to hugs all around . Circular in cross-section column
These techniques are very effective , improving the deformation properties of the concrete column
Besides , increase of strength of concrete to increase the capacity as a result of axial
provides a . That allows wrapping , due to the problem of insufficient clamping length
which is very suitable for this technique also helps to increase the shear strength .
 
 
 
b . Strengthening beam
Earthquake safety is a priority in terms of the strengthening of the beams , but some
In case you may have . The main techniques are commonly used are listed below :
 
• New concrete layer - new and old beams connected to the longitudinal reinforcement to provide
or Z - welded stirrup iron comprising adding a new concrete layer . new
In case of end fittings so good clenching , lot in increasing the flexural capacity
is effective.
• steel plate or fiber reinforced polyester - or carbon steel plate or the like fibrous
polyester strips , the new face of the beam tensile reinforcement bonding with epoxy .
Very good condition ends clenching , can be effective in increasing the flexural capacity .
 
• Cutting equipment as handcuffs - along the beam , the beam with bolts tightened around
Placing steel clamps . Outside the shear strength of the hoop clamps which are the
In case of inability to form a suitable solution .
• Screen rotation coupling beam beams - in order to improve the system behavior under
new curtains in the carrier system is created, it is adjacent to the walls
beams, girders rest , especially between two curtains , curtain tie beams transformed into a
bending moments and shear forces on a lot of capacity to take the start .
Therein sufficient to impart a bending capacity is often not possible ; such
In cases of hinged at the two ends of these beams avoided assuming that
ductile behavior can be satisfied by measures to ensure the wrapping . However, the two
end hinged to occur in the provision of cutting capacity , which corresponds to the moment
and prevention of shear failure is absolutely necessary.
c . Floor Strengthening
Earthquake strengthening of security in terms of the floor , only the aperture effect
agenda in terms of revenue ; If you or particularly pretty thin slab contains emptinesses ,
in the plane of the force is insufficient to transfer ( in this case, a filler
are frequently encountered in laying ) , ensuring cohesion with existing shed and a paved
A new layer of concrete reinforcement mesh can resolve this problem often . diaphragm
effect as well , which is effective in enhancing the bending capacity , in which a roughened
concrete surface creation and use of cutting nails is important .
 
2.3.2. System Behaviour Improvement
Some operations or structures attached to the bearing element in response to some new structures
General behavior of the system may be varied considerably ; as a result, the existing structure
elements can be brought into a much lower and thus conveying force existing
be sufficient for them to strengthen capacities and also may be needed. structure
systems aimed at changing the nature of such transactions " system behavior improvement "
is called.
a. Saving elements forming lateral rigidity
Creating new elements that provide lateral rigidity of the structure of a large earthquake
portion of the frame members so that new elements to be transported and extreme
Recovering from installation through the improvement of system behavior . This approach
The main techniques used to perform the following:
 
• Cast in-situ reinforced concrete infill walls - Comprehensive experimental research
developed this technique has been applied successfully in the repair work
In Turkey with this technique , considerable knowledge and experience in a level
accumulation has occurred. However, the structure for a long period of forced evacuations
Because this technique is applied to a large number of buildings , which comes before the earthquake,
is not conducive to comprehensive strengthening exercises .
 
• Strengthening of brick infill walls ( fiber reinforced polyester ) - As mentioned above
As in Turkey, hollow brick infill walls in reinforced concrete frame structure is very
is widely used . Although considered in calculations taken, these walls
an effect on the structure of the seismic response , and an addition on earthquake resistance
are known to have . However, in certain forms of crunchy break under load
they lose their effectiveness , these walls be relied upon to provide earthquake resistance
It is not possible . However , if it strengthened by some suitable methods , as
significant and reliable strength qualities which make a contribution , as well as
cast in-situ reinforced concrete infill walls reminiscent of the format of the structure, behavior
has proven they can improve . Developed in line with this principle from two effective techniques
One structure, hollow brick infill walls of some of the available fiber reinforced polyester
through the strengthening of the strips glued with epoxy . Selected two eyes
way the strips arranged transversely to the existing concrete frame members
securely clamped in cases where this technique is effective , to building users
can be easily implemented without significant discomfort .
• Strengthening of brick infill walls ( precast concrete panels ) - above
In line with the approach described , the existing hollow brick infill walls
users that can be used to strengthen the structure and still an important
Another technique that can be applied without disturbing the high strength concrete
produced at the factory , and the doors are thin and can be easily moved by two people
precast concrete panels that can be passed in size to the existing brick infill walls and
through the epoxy is adhered to the frame member . Which is very easy to implement
this technique and lateral rigidity to withstand seismic loads very large proportions
can be improved.
• Steel braces use - Chosen frame steel braces into the eyes
placing the increased rigidity of the structure and lateral resistance , the first from the system
techniques is one of behavior . However, in principle it is very effective and meaningful
technique with great difficulty is encountered in the practice in Turkey . existing
The concrete structure is usually unskilled and frames important design
widely due to the presence of defects , especially in the framework of steel cross
they sit in joints , steel cross can provide the increase in capacity
is reached long before the breach occurs .

Prestressing ( then pull) applications - in the context of the above steel bracings
In line with the approach outlined selected frame to the eyes , cross- arranged
then pull the rope through the implementation of the biasing to the mind a geliver
are other approaches . However, for the reasons mentioned similar problems in this approach
are encountered . Also, biasing the frame member for connecting ropes
necessary arrangements are quite complicated . This approach completely different from
Although there are , especially in seismic strengthening of masonry structures , structure
In order to save the integrity of the biasing effective and useful applications
that should be mentioned here .
• Building a new structure outside the establishment - in Turkey is not permitted by zoning rules
because very rarely applied , but that does not disrupt the use of some
Another approach in countries preferable in some cases , outside the structure , structure
independent , high lateral stiffness of the structure to a new structure creation and strengthening
This new structure is a place you can get connected to support her case to be brought to
approach.
b . Removal of earthquake effects
Seismic effects may be transferred to the structure as the prevention or only a small
Ensuring transfer of a portion of the structure . In this approach, the regulations and
with the help of various tools and equipment used on the floor of the structure of earthquake motion
inhibiting the transfer is intended . The most common of which is the base isolation .
• Floor insulation ( Base isolation ) - to reflect the application of the principles mentioned above
In order placed on the basis of their structural , allowing certain degree of lateral offset mAlArA
and in which various embodiments may provide energy consumption can be complimented
was developed . Which can not be avoided , and displacements caused substantial size
several challenges must be overcome , but in the developed countries of this embodiment,
has been used successfully . In Turkey, it is considered particularly important in the construction of buildings
when it is observed that increased use of such devices . However
with existing structures to be placed in this düzeneklr both are fairly complex, and
the structure requires special precautions . Strengthening against earthquakes
The vast majority of buildings in need of a large number of reinforced concrete structures is unqualified
If you remember , this approach is a convenient and affordable to strengthen buildings in Turkey
create a solution appears to be very questionable .
 
3 STRATEGY FOR STRENGTHENING
At the beginning of the previous section , three groups of data while creating an augmentation strategy
states that must be evaluated ; then the building stock in Turkey
Establishment of earthquake safety the most important segment data for these three groups
collectively had been revised . These data strengthen the basis for Turkey
identification strategy is the subject of this chapter .
Subject From the perspective of a single structure , the structural weaknesses of the structure with a particular region
carrier does not appear to be limited or sufficient in cases where a small number of elements
elements of empowerment approach should be favored ; however, insufficient number of elements
or lateral rigidity is greater due to the lack of adequate vertical carrier of all
Where necessary to strengthen , by one of several supporting elements
not significant strengthening , instead of system behavior improvement approach
It is clear that to adopt a much more accurate . Naturally, the same understanding , similar features
for which a certain group of buildings , the buildings in a city or in a country for all
applies . Thus , Turkey will be defined strategy to strengthen the foundations of
appropriate structure to take stock of the important segments of the common weaknesses ,
• Almost all the structures seen in this group and insufficient lateral stiffness
• Nearly all structure elements seen in the reinforcement arrangement with defects
• Very common use of low-quality concrete
Given the system behavior that priority should be given to improvement approach
is apparent . As a result of such a process , the majority of seismic forces
lateral rigidity is taken by the newly created elements , the majority of which is insufficient
frame members to relax and to carry only vertical loads from the force
being inadequate because they are often forced to quit . However ,
a small number carrier element or the base element is still insufficient (curtains bond
Back to the beam as the beam ) due to undergo functional changes , strengthening
It is natural to require . However , a small number of individual elements for the potentiation of
There is no any hassle .
This understanding will be held in retrofit applications that require strengthening of
technology available in Turkey , in many cases a variety of techniques to engineer
It offers the option occurs .
This approach , when seen in terms of the security level seems to be suitable . In fact ,
the country's limited economic opportunities , to minimize the number of casualties a priority objective
'should be given that this approach prevention security levels immigrants
can be easily applied as directed . However , a higher level of security
When selected, there is no barrier to be applied the same approach .
 
As discussed above , " primarily with a view to improving the overall system behavior
To overcome the deficiencies in the then still small number carrier element
implement individual empowerment " of an augmentation strategy can be summarized as Turkey
There seems to be well suited for .
Indeed, in many years , mainly from Middle East Technical University research and
developed within the framework of the implementation of this augmentation strategy , in Turkey today
broadly implemented. However, this practice is often without conscious
carried out , so also several inaccuracies and omissions are inevitable in practice
it is . Here defined simply based on the basic principles of this strategy engineers
absorbed by proposing the use of time and which are briefly summarized in this paper
strengthen the technical concepts that form the basis for the behavior of practitioners
clearly reflected in the format understood by much more successful when
There is no doubt the results will be taken .

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