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cross-section column

the cross section of the column model consists of confined concrete ( conf )

non-confined concrete ( unc )

has the following characteristics

characteristic rate

sectional shape rectangular

Width 30 cm

height 40 cm

reinforcement at corners 4/16

reinforcement upper and lower cheek Φ/12

lateral sidewall reinforcement 2/12

total reinforcement 4/16+6/12

Figure 6. section column

http://postimg.org/image/3yjmc0263/
Distinguish three different materials

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cross-section beam

The cross beam consists of confined concrete ( conf )

non-confined concrete ( unc )

has the following characteristics

characteristic rate

sectional shape T-shaped plate-girder

effective width 100 cm

slab thickness 15 cm

beam height 60 cm

beam width 25 cm

reinforcement beam down 3/14

reinforcement beam over 2/14

Buccal armature beam Φ10/cheek

armor plate over 6/10

armor plate under 4/10

total reinforcement 5/14+12/10

Figure 7. cross beam. distinguish three different materials.

http://postimg.org/image/liebad51d/
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finite elements

the finite element models used in the building is a three-dimensional non - linear ribbed finite element based on the strength

(3D Inelastic force-based element ) with 4 integration points along with visa fibers.

The number of fibers in each section is 200

this item is used for the simulation of columns and beams.

Figure 8. finite element space, to simulate columns and beams

http://postimg.org/image/48p23wyrb/
4.4 analysis - methodology

performed nonlinear analyzes for each building with the finite element method, taking into consideration effects of nonlinearity of material and geometry.

analyzes are non-linear, static ( pushover ), while charging a triangular distribution

height which corresponds approximately to the first peculiarity of the examined structure

The total number of trainees loads has rate 1kN that the base shear during charging it to a rate 1kN and therefore importune coefficient λ is equal to the base shear (1*λ) for the various phases of the analysis.

value - the objective of the movement is set at 0.18 m

The load is transmitted in 50 steps for both models.

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As a control node set node of higher level of construction ( z=max ) to whom x=0 and y=0, as shown in more detail in Figures

The proposed system causes the exercise of a compressive force in each column where applicable.

The simulation of this phenomenon

been addressed by imposing a compressive strength in columns

considered that the system applies.

5. three-storey reinforced concrete building

5.1 general characteristics of the building.

the test building displays regularity

in plan and height.

general characteristics of the building.

floor height............................................ .......3m

span length x ...............................................5m

span length z ...............................................5m

diaphragm ....... yes on each floor

supports .......... anchors on all nodes with z=0 (ground)

Figure 9. plan three-storey building

http://postimg.org/image/a050s6yg7/
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Figure 10. front face of the three-storey building

http://postimg.org/image/viypllunn/
Figure 11. side view of the three-storey building

http://postimg.org/image/6mws5h4vb/
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Figure 12. perspective view of a three storey building (a)

characterized the control node of the structure

http://postimg.org/image/kqx8rm1gn/
Figure 13. perspective view of a three storey building (b)

characterized the control node of the structure.

http://postimg.org/image/jzxkdmhvb/
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5.2 analytical results

5.2.1 without the application of prestressing.

The following figure shows the diagram

base shear - displacement for node monitoring.

Figure 14. power curve (kN) - displacement (m) without the application of prestressing

http://postimg.org/image/jzxkdmhvb/
the maximum value of the chart is 900.62 kN, illustrated for the displacement of the control node 0.1296 m

5.2.2 compressive load 600 kN to nodes of higher level.

Applied compressive load 600 kN to nodes of higher level due to the prestressing force.

Initial (A) charged with the compressive force the central column.

then (B) the load applied to the four corner columns.

to the end (C) loaded all the 9 columns of the building

The positive trend in each column is ..

600 kN / (0.30 m * 0.40)=5000 kN/m2=5MPa

the ultimate limit state of column

because grief

(Taking into account the safety factor

having a value of 1.5 for concrete),

the tensile strength for concrete C 30 is 30 MPa/1.5=20MPa.

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therefore the positive trend in the columns corresponding to the 5/20 = 25% strain at break,

the ultimate limit state.

A. Compressive load of 600 kN to the central hub of higher level.

The diagram below shows the chart base shear-movement

for the control node.

Figure 15. power curve (kN) - displacement (m) applying compressive load 600 kN at 4 corner nodes of higher level

http://postimg.org/image/50gpcep27/
the maximum value of the diagram without the application of prestressing was

600.62 kN for displacement 0.1296 m

the maximum value of the chart by applying a compression load 600

to the central hub of the upper level is

929.82 kN for displacement 0.1116 m

improving the carrying capacity is

978.77 - 929.82 = 48.95 kN

the percentage improvement in base shear is

48.95 / 900.62 = 5.4%

result

There is a slight improvement in the carrying capacity of the building,

due to the application of the compressive load on the central column of the building.

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B.Compressive load 600 kN at 4 corner nodes of higher level.

The following figure shows the base shear diagram

- Movement on the control node.

Figure 16. power curve - Shift by applying compressive load 600 kN at 4 corner nodes of the upper level

http://postimg.org/image/pakwo6603/
the maximum value of the diagram without the application of prestressing was

900.62 kN for displacement 0.1296 m

the maximum value of the chart by applying a compression load 600 kN at 4

corner nodes of the upper level is.

978.77 kN for displacement 0.1044 m

improvement in carrying capacity is.

978.77 - 900.62 = 78.15 kN

the percentage improvement in base shear is.

218.39 / 900.62 = 8.7%

result

there is a slight improvement in the bearing capacity of the building, through the application of compressive forces in the four corner columns of the building.

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Γ. Compressive load 600 kN on all nodes of higher level.

The following figure shows the diagram base shear - displacement for node control

Figure 17. power curve ( kN ) - displacement ( m )

applying compressive load 600 kN on all nodes of higher level

http://postimg.org/image/i7pfrq2sd/
the maximum value of the chart without applying prestressing was

900.62 kN for displacement 0.1296 m

the maximum value of the chart by applying a compression load 600 kN to all nodes of the upper level is

1,119.01 kN for displacement 0.1008 m

improvement in bearing capacity is 1119.01 - 900.62 = 218.39 kN

The percentage improvement in the maximum base shear is 218.39 / 900.62 = 24.2%

result

observed a significant improvement in the bearing capacity of the building, through the application of compressive forces in all the 9 columns of the building

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5.2.3 compressive load 1,200 kN to nodes of higher level

applied compressive load 1,200 kN to nodes of higher level, ratio of prestressing force.

initially ( A ) charged with the compressive strength the four corner columns

slowly charged and nine columns of the building

applied compressive load 1,200 kN to nodes of higher level due to the prestressing force.

The positive trend in each column is

1200 kN / ( 0.30 m *0.40 m ) = 10,000 kN/m2 =10 MPa

the ultimate limit state of the column due to grief (taking into account the safety factor has a value of 1.5 for concrete)

the tensile strength for concrete C 30 is 30 MPa / 1.5 = 20 MPa

therefore

The positive trend in columns

corresponds to 10/20 = 50% strain at break

A. compressive load 1,200 kN at 4 corner nodes of higher level

The following figure shows the base shear diagram - movement on the control node.

Figure 18. power curve (kN) - Displacement (m) applied compressive load 1,200 kN at 4 corner nodes of higher level.

http://postimg.org/image/4ix16x4o3/
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the maximum value of the chart without applying prestressing was

900.62 kN for displacement 0.1296 m

the maximum value of the chart by applying compressive load 1200 kN at 4 corner points of the maximum level is

995.46 kN for displacement 0.1188 m

improvement in bearing capacity is

995.46 - 900.62 = 10.5%

result

there is a slight improvement in the bearing capacity of the building, through the application of compressive forces in the four corner columns of the building.