rekha CE PORTFOLIO

CIVIL ENGINEERING PORTFOLIO V.REKHA

CONTACT INFOEmail:

[email protected]:

8897810935Address:

E-31 Ultra Tech TownshipTadipatri, BhogasamudramAnantapur district-515415

mailto:[email protected]

HELLO!I AM V.REKHAI’m pursuing MASTER’S in COMPUTER AIDED STRUCTURAL ENGINEERING at JNTUA. My aim is to make a position for myself in the competitive corporate world and contribute to achieving the goals on both professional and personal level"

KEY SKILLS:

AutoCAD

Staad-Pro

SAP2000

Google Sketchup

Currently looking for “STRUCTURAL DESIGN ENGINEER” position

ACADEMICMasters in Technology (CIVIL ENGINEERING)

Jawaharlal Nehru Technological University (JNTUA), Anantapur (Pursuing) Secured 68% in 1st yr.

Bachelors in Technology (CIVIL ENGINEERING) J.B.Institute of Engineering & Technology, Hyderabad, in 2014

Secured 70% marks.

Board of Intermediate (M.P.C) Sri Chaitanya Junior College, Hyderabad in 2010

Secured 86% marks.

Secondary Education (10th class)

L&T CSI PUBLIC School in 2008. Secured 78% marks.

MTEC PROJECT: Performance of lateral systems on tall buildings

• The advances in three-dimensional structural analysis and computing resources have allowed the efficient and safe design of increasingly taller structures. These structures are the consequence of increasing urban densification and economic viability. The present work aims to demonstrate the performance of building considered with outriggers, tube in tube, bundled system. • The building studied in this work is a reinforced concrete moment resisting

frame (G+40) designed for gravity and seismic using 1893:2002. And is studied using Non-linear time history analysis. These building models are analyzed, using SAP 2000 software, to the action of lateral forces employing non-linear dynamic approaches as per IS 1893 (Part I): 2002. The results of the analyses, in terms of lateral deformations, respective storey drifts and base shears are obtained and the conclusions are drawn thereof.

CLASSIFICATION OF TALL BUILDING STRUCTURAL SYSTEMS-Interior Structures

Exterior Structures

TUBE STRUCTURES• Tube design can be defined simply as a structural system that

prompts the building to behave as an equivalent hollow tube.Tubular systems are so efficient that in most cases the amount of structural material used is comparable to that used in conventionally framed buildings half the size.• Lateral loads were resisted by various connections, rigid or semi rigid,

supplemented where necessary by bracing and truss elements. • Further improvement in the structural economy was achieved by

engaging the exterior frame with the braced service core by tying the two systems together with outrigger and belt trusses. This was perhaps the beginning of tubular behavior since the engagement of the exterior columns is similar to that of the tube structure.

FRAMED TUBEThe method of achieving the tubular behavior by using closely spaced exterior columns connected by deep spandrel beams is the most used system because rectangular windows can be accommodated in this design. The framed tube requires large columns and deep beams Design of the tube structure assume a linear distribution and shear lag results in comer column experiencing greater stresses than central perimeter columns. This shear lag is a result of local deformation of beams which leads to a reduction of axial stress near the centre of the flange. The redistribution of these axial loads results in the corner perimeter columns becoming overstressed.

TRUSS TUBEThe frames parallel to the wind essentially act as multi-bay rigid frames with bending moments

in the columns and beams becoming controlling factors in the design. As much as 75 percent of the total lateral sways results

from racking of the frame as a direct consequent of shear lag. One method of Overcoming the problems resulting from

the framed tube is to stiffen the exterior frames with diagonals or trusses. The resulting system

is commonly known as a trussed tube.

BUNDLED TUBEA bundled tube structure is essential by structure resulting from combining two or more independent tube structures designed to act as one. The structural concept behind the bundled tube is that the interior columns from the individual tube act as internal webs of the cantilever structure. This results in a substantial increase in shear stiffness over the other tubular designs with no lateral resisting interior frames or columns. Increased shear resistance results in a reduction in the shear lag effect.

NON LINEAR DIRECT INTEGRATION TIME HISTORY ANALYSIS IN SAP 2000

• Following are the general sequence of steps involved in performing NLTHA using SAP 2000 in the present study:• A two or three dimensional model that represents the overall structural behaviour created.• For reinforced concrete elements the appropriate reinforcement is provided for the cross sections.• Frame hinge properties are defined and assigned to the frame elements.• Gravity loads composed of dead loads and a specified proportion of live load is assigned as seismic weight to

the structure.• Free vibration un-damped modal analysis is performed to make note of the frequencies and time periods of the

structure.• The time history function from a file is selected and the time history function is defined.• The non-linear direct integration time history load cases are defined by assigning the ground acceleration time

history function as loading in X and Y directions. and by assigning proportional damping • NLTHA is set to run.• After the analysis is completed the displacement pattern of the structure is studied and inter story drifts are

calculated.• The hinge pattern is studied to assess the performance of the structure.• The other responses such as base shear, member forces, and response spectrum curves are noted.

BUILDING DESCRIPTIONModel1: In the first model, a 30 storiedreinforced concrete frame building situated in zoneV, is taken for the purpose of study.The plan area of building is 18 x 18m with 3m as height of each typical storey. It consists of 6 bays in X-direction and 6 bays in Y-direction.Model Plan

Elevation

Structural dimensions of 30 storied building

S. No. Description Information Remarks

1 Plan size 18mx18m -------

2 Building heights 90m -------

3 Number of storey’s above ground level 30 -------

4 Number of basements below ground 0 -------

5 Type of structure RC frame -------

6 Open ground storey Yes -------

7 Special hazards None -------

8

Type of building

Regular frame with open ground storey

IS-1893:2002 Clause 7.1

9 Horizontal floor system Beams & Slabs -------

10 Software used SAP 2000 -------

S. No. Specifications 30 storey

1 Slab Thickness 150mm

2 Beam dimensions 400x600mm

3 Column dimensions 700x700mm

4 Shear wall Thickness 150mm

4 Grade of concrete M35

5 Grade of steel Fe-500

6 Unit weight of concrete 25kN/m3

7Live loads

(a) Floor load(b) Floor finishes

4kN/m2

1.25kN/m2

10 Importance factor 1.0

11 Seismic zone factor 0.36

12 Response reduction factor 5

Model 2:In the Second model, a 30 storied reinforced concrete frame building with shear wall situated in zoneV is taken for the purpose of study. The planarea of building is 18 x 18m with 3m as height of each typical storey. It consists of 6 bays in X-direction and 6 bays in Y-direction. Model Plan

Elevation


S. No. Specifications 30 storey

1 Slab Thickness 150mm

2 Beam dimensions 400x600mm

3 Column dimensions 700x700mm

4 Shear wall Thickness 150mm

4 Grade of concrete M35

5 Grade of steel Fe-500

6 Unit weight of concrete 25kN/m3

7Live loads

(a) Floor load(b) Floor finishes

4kN/m2

1.25kN/m2

10 Importance factor 1.0

11 Seismic zone factor 0.36


S. No. Description Information Remarks1 Plan size 18mx18m -------2 Building heights 90m -------3 Number of storey’s above ground level 30 -------4 Number of basements below ground 0 -------5 Type of structure RC frame with

shear wall-------

6 Special hazards None ------- 7

Type of building


IS-1893:2002 Clause 7.1

8 Horizontal floor system Beams & Slabs -------9 Software used SAP 2000 -------

Model 3: In the Third model, a 30 storied outrigger frame building- one storey module situated in zoneV is taken for the purpose of study. The plan area of building is 18 x 18m with 3m as height of each typical storey. It consists of 6 bays in X-direction and 6 bays in Y-direction. Model Plan

Elevation


S. No.

Specifications

30 storey

1Slab Thickness 150mm

2Beam dimensions

230x500 mm230x450mm

3 Column dimensions 700x700mm4 outrigger 300x300mm5

Grade of concrete M356

Grade of steel Fe-5007

Unit weight of concrete 25kN/m3

8 Live loads(a) Floor load

(b) Floor finishes4kN/m2

1.25kN/m2

9Importance factor 1.0

10Seismic zone factor 0.36


S. No. Description Information Remarks1 Plan size 18mx18m -------2 Building heights 90m -------3 Number of storey’s above ground level 30 -------4 Number of basements below ground 0 -------5 Type of structure Outrigger

structure-------

6 Special hazards None ------- 7

Type of building


IS-1893:2002 Clause 7.1


Model 4: In the fourth model, a 30 storied Tube in Tube building situated in zoneV is taken for the purpose of study. The plan area of building is 18 x 18m with 3m as height of each typical storey. It consists of 6 bays in X-direction and 6 bays in Y-direction.Model Plan

Elevation


S. No.

Specifications

30 storey


2Beam dimensions 400x600mm

3 Column dimensions 700x700mm4 Shear wall Thickness 150mm4






1.25kN/m2




S. No. Description Information Remarks1 Plan size 18mx18m -------2 Building heights 90m -------3 Number of storey’s above ground level 30 -------4 Number of basements below ground 0 -------5 Type of structure Tube In Tube -------6 Special hazards None ------- 7

Type of building


IS-1893:2002 Clause 7.1


Model 5:In the fifth model, a 30 storied Bundled Tube building situated in zoneV, is taken for the purpose of study. The plan area of building is 18 x 18m with 3m as height of each typical storey. It consists of 6 bays in X-direction and 6 bays in Y-direction.Model Plan

Elevation


S. No.

Specifications

30 storey


2Beam dimensions 400x600mm

3 Column dimensions 700x700mm4






1.25kN/m2




S. No. Description Information Remarks1 Plan size 18mx18m -------2 Building heights 90m -------3 Number of storey’s above ground level 30 -------4 Number of basements below ground 0 -------5 Type of structure Bundled Tube -------6 Special hazards None ------- 7

Type of building


IS-1893:2002 Clause 7.1


RESULTS

0 5 10 15 20 25 30 350

100

200

300

400

500

600

RCCBUNDLED TUBE IN TUBE out-riggerSHEAR WALL

storeys

disp

lace

men

t

Displacement of Models Modal Periods Moments

0 5 10 15 20 25 30 350.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

RCCBUNDLED TUBE IN TUBE OUTRIGGER30 RCC SHEAR WALL

STOREYS

DR

IFT

Storey

-30

Storey

-26

Storey

-22

Storey

-18

Storey

-14

Storey

-10

Storey

-6

Storey

-20

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

TUBE IN TUBEBUNDLED TUBEoutriggerRCC WITH SHEARWALLRCC

Time period Base Shear BaseMoment

0 2 4 6 8 10 12 140

1

2

3

4

5

6

7

RCC

BUNDLED

TUBE IN TUBE

outrigger

SHEAR WALL

MODES

TIM

E P

ER

IOD

S

BASE SHEAR0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

RCCBUNDLEDTUBE IN TUBEOUTRIGGERRCC SHEAR WALL

10

100000

200000

300000

400000

500000

600000

700000

800000

900000

RCCBUNDLEDTUBE IN TUBEOUTRIGGERRCC SHEAR WALL

Axial Force Shear Force

Storey

-30

Storey

-27

Storey

-24

Storey

-21

Storey

-18

Storey

-15

Storey

-12

Storey

-9

Storey

-6

Storey

-30

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000


Storey

-30

Storey

-28

Storey

-26

Storey

-24

Storey

-22

Storey

-20

Storey

-18

Storey

-16

Storey

-14

Storey

-12

Storey

-10

Storey

-8

Storey

-6

Storey

-4

Storey

-20

50

100

150

200

250

300


CONCLUSIONS

The overall results suggested that bundled tube is excellent seismic control for high-rise symmetric Buildings. As we have seen, the bundled ,diagrids, the latest mutation of tubular structures, has in addition to strength and aesthetics, that extra quality of geometric versatility, making it the most suited structural system to this respect.

Thus the bundled tube and outrigger, with an optimal combination of qualities of aesthetic expression, structural efficiency and geometric versatility is indeed the language of the modern day builder.

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rekha CE PORTFOLIO