Design and Analysis of Ladies Hostel using STAAD PRO
1. 1
CHAPTER 1
INTRODUCTION
1.1 GENERAL
The project is to Construct a Ladies Hostel in M.A.R
Campus. The Hostel Building is an G+3 Building with an overall Plinth Area is
16072.89 m2. The Ground Floor consist of Visitor Hall, Security Room,
Prayer Hall, Warden room, Gym, Guest room, T.V Hall, Kitchen &Mess Hall.
The Other Three Floors consist of 30 Rooms per one Floor. Each Rooms
Consist of Writing & Reading Table, Stepped cot, Attached Bath room &
Toilet . STAAD pro 2008 enables a Faster Approach to The Analysis And
Design of the Framed Structures.
1.2 ANALYSIS
Analysis of the structure can be done either manual method or by
using software. Analysis of the structure is done by using the software package
STAAD Pro 2008 with the aid of this software the analysis of the structure is
simple and comfortable for Civil Engineers. Various load combination can be
easily analyzed using this software. The shear force and bending moment for
Individual as well as composite members can be easily obtained. The analysis is
usually a time consuming process. By using this software we can save the time.
2. 2
1.3 DESIGN
Using the data obtained from the STAAD analysis, the design
is done manually by limit state method of design. The design of beams and
columns are done for its maximum moments. The designs can be done manually
with the help of the codal provisions namely IS456-2000, SP16 etc., using limit
state method of design.
1.4 DESIGN PHILOSOPHY
Reinforced concrete structure can be designed by using one of
the following design philosophies.
Working stress method (WSM)
Ultimate load method (ULM)
Limit state method (LSM)
Working stress method used over decades is now practically
out dated it is not used at all in many advanced countries of the world because
of its inherent drawback. The latest IS code gives emphasis on limit state
method which is the modified version of ultimate load method.
It is a judicious amalgamation of WSM and ULM removing
all drawbacks of both methods but maintaining their good points.
Limit state method has proved to have an edge over the
working stress design from the view point of economy. The Government
departments and large consulting firms are switching over to this method.
1.5 R.C.C WORK
1.5.1 COLUMN
The column will be provide for the size of 0.3mx0.3m and
height of the column is 3.2m in R.C.C cement concreteM20 grade mix in using
12mm HYSD metal bars.
1.5.2 BEAM
3. 3
The beam will be provide with size of 0.45X0.3m in R.C.C
cement concreteM20 grade mix in using 20mm HYSD metal bars.
1.5.3 FOOTING
The foundation for all footing will be in R.C.C cement concrete
M20 grade mix in using 16mm HYSD 800mm thick with plan area 2x2m
footing will be 4500mm below the ground level
1.6 SCOPE:
In the construction industry the design and structural engineers
have switched to the technology tools. In this project efforts are made to
completely utilize the software for the static analysis and dynamic analysis of
the frame structure and to reinforce the correctness of use of software namely
STAAD pro and design is carried out manually using the analysis results.
1.7 OBJECTIVE OF THE PRESENT PROJECT
Planning, analysis and designing of hostel block RC framed structure.
Analyses the frame structure both statically and dynamically.
Design of the structural elements suchas beams and columns using
STAAD Pro 2008 analysis result.
4. 4
CHAPTER 2
LITERATURE REVIEW
2.1 GENERAL
A critical summary and an assessment of the current state of
knowledge or current state of the art in a particular field.
The ability to carry out a literature review is an important skill for
any student. It will provide you with to place your assignments regardless of the
module you are studying. Practically any assignment, gathering information to
refuge or support specific arguments, and writing about our findings.
Understanding the literature in your research topic will prevent you from
repeating previous errors, or redoing work which has already been done. It will
also give you insights into aspects of your topic which might be worthy of
exploration and future research.
Design has many meanings and perspectives. Design is primary a
communication process its purposeis to convey information about a productor
an organization to consumers or clients. DESIGN CREATS Satisfaction for
consumers and profits for the company and essential to strategic marketing
planning.
2.2 LITERATURE REVIEW.
C.K. Wang and C.G. salmon (2011) gives ideas to calculate
quantities and specifications for construction and fabrication. The drift
was kept to within H/500, where theory for design adapted was, from
text books by C.K. Wang and C.G. salmon in Reinforced Concrete Design
and J.G. Mc Grager, Reinforced Concrete Design, and S.Rajasekaran,
Finite element method.
5. 5
Fred Carrie, Abraham Pinales and Antonio Duarte, (2011)
made project under the structural analysis and design of 4 story
multistory building complex for the hostel for legislators of Tamil Nadu
State in Salem, Tamil Nadu, in India, is described herein. This is a result
of a senior thesis project completed by 3 senior students. Fred Carrie,
Abraham Pinales and Antonio Duarte, of Worcester Polytechnic Institute,
Worcester, Massachusetts, carried out at its India Project Centre, at
PSG College of Technology, Coimbatore, India. Salem is a sister city of
Salem, Massachusetts. Gravity and Lateral loads were determined using
Canadian Code 1995, ANSI Standards 1995 and Indian Standards 1990.
Colin clipson (1990), a leading proponent of design management
adds that, “All outcomes of design are imbued with some symbolic or emotive
content; this applies equally to a product a building, communication or aservice.
Philip Kolter and Alexander Rath (1984) describe the difference
between functional and visual design as the difference between the design of a
nuclear power plant and the design of wallpaper.
In addition, Kotler and Raath (1984) says “Well-managed ,high-
quality design offers the company several benefits. It can create corporate
distinctiveness in an otherwise product-and image-surfeited market place
David A. Fanella, Ph.D., S.E., P.E., F.ASCE, (2010) is Associate
Principal, Klein and Hoffman, Inc., a structural and restoration engineering
firm. He is the author of numerous technical publications including
Design of Low-Rise Concrete Buildings Based on the 2009 IBC (ICC;
2009) and a series of articles on time-saving design methods for
reinforced concrete. Dr. Fanella took part in the post-9/11 investigation of
World Trade Center Towers 1, 2, and 7, and was the primary author of
6. 6
reports detailing the methods and codes used during the design and
construction of the structures.
Grop (1982) Defines what design is for managers and why it should
be important to them. Design is the planning process for the things you make
(which are your products). It can ,but need not necessarily be, concerned with
the aesthetics of your product.
8. 8
CHAPTER 4
STAAD PRO INPUT DATA
4.1 INTRODUCTION
For analysing and designing of a building involves tedious
calculation. If it is done by manually it cause lot of errors and it is
difficult also. Now this tedious calculation are done by software package
named STAAD PRO .It will decrease Errors in manual calculations and very
time consuming process . here it done by STAAD PRO 2008 software.
4.2 PRIMARY LOAD CALCULATION FOR STAAD PRO INPUT
4.2.1 Dead Load:
(a) Self weight:
Self weight for beam, column and slab-self weight Y -1
(In STAAD PRO – 2008 version self weight will automatically
assign by software itself since we gave proprety of beam ,column and slab
elements)
(b) Slab DeadLoad : (Apply As FloorLoad)
Dead load of slab = 14 KN/m2
Dead load of parapet wall = 3.68 kN/m2
This load is assign automatically for the relevant structure
4.2.2 Live Load:(Apply FloorLoad)
Live load of building = 4 kN/m2
43. 43
ELEMENT PROPERTY
1344 1346 1348 1349 1351 TO 1394 1396 TO 1405 1408 TO 1433 1436 TO
1441 1443 -
1444 TO 1463 1466 1468 1469 1484 1485 1488 TO 1531 1533 TO 1543 1546
TO 1552 -
1555 TO 1565 1572 TO 1574 1577 1578 1583 TO 1637 1639 TO 1645 1648
TO 1661 -
1664 2025 TO 2029 2031 TO 2052 2055 TO 2074 2077 2078 2083 2085 2087
TO 2089 -
2091 2092 THICKNESS 0.15
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 2.17184e+007
POISSON0.17
DENSITY 23.5615
ALPHA 5.5e-006
DAMP 0.05
END DEFINE MATERIAL
MEMBER PROPERTYAMERICAN
285 287 291 293 295 TO 303 306 TO 311 313 TO 317 322 TO 344 350 351
355 358 -
359 TO 367 369 373 375 379 381 TO 398 400 TO 402 520 522 526 528 530
TO 538 -
541 TO 546 548 TO 552 557 TO 579 585 586 590 593 TO 602 604 608 610
614 616 -
617 TO 633 635 TO 637 755 757 761 763 765 TO 773 776 TO 781 783 TO 787
792 -
793 TO 814 820 821 825 828 TO 837 839 843 845 849 851 TO 868 870 TO
872 990 -
44. 44
992 996 998 1000 TO 1008 1011 TO 1016 1018 TO 1022 1027 TO 1049 1055
1056 -
1060 1063 TO 1072 1078 1080 1084 1086 TO 1103 1105 TO 1107 1225 1227
1231 -
1233 1235 TO 1243 1246 TO 1251 1253 TO 1257 1262 TO 1284 1290 1291
1295 1298 -
1299 TO 1307 1309 1313 1315 1319 1321 TO 1342 1869 TO 1872 2123 TO
2127 2131 -
2132 TO 2135 2139 TO 2143 2147 TO 2151 2155 TO 2160 PRIS YD 0.45 ZD
0.3
168 170 TO 284 403 405 TO 519 638 640 TO 754 873 875 TO 989 1108 1110
TO 1223 -
1224 PRIS YD 0.3 ZD 0.3
MEMBER PROPERTYAMERICAN
286 288 TO 290 292 294 304 305 312 318 TO 321 345 346 348 374 376 TO
378 380 -
521 523 TO 525 527 529 539 540 547 553 TO 556 580 581 583 609 611 TO
613 -
615 756 758 TO 760 762 764 774 775 782 788 TO 791 815 816 818 844 -
846 TO 848 850 991 993 TO 995 997 999 1009 1010 1017 1023 TO 1026 1050
1051 -
1053 1079 1081 TO 1083 1085 1226 1228 TO 1230 1232 1234 1244 1245 1252
1258 -
1259 TO 1261 1285 1286 1288 1314 1316 TO 1318 1320 1665 TO 1824 1837
TO 1854 -
1859 TO 1868 1873 TO 2024 2076 2079 2084 2086 2090 2093 TO 2122 2128
TO 2130 -
2136 TO 2138 2144 TO 2146 2152 TO 2154 2161 TO 2230 PRIS YD 0.45 ZD
0.3
45. 45
CONSTANTS
MATERIAL CONCRETEALL
SUPPORTS
19 21 29 36 TO 39 41 43 45 46 49 TO 51 56 59 TO 73 75 TO 79 81 84 TO 107
110 -
112 TO 139 141 TO 162 164 166 TO 168 170 172 FIXED
LOAD 1 LOADTYPE Dead TITLE DEAD LOAD
SELFWEIGHT Y -1 LIST 168 170 TO 346 348 350 351 355 358 TO 367 369 -
373 TO 398 400 TO 403 405 TO 581 583 585 586 590 593 TO 602 604 608 TO
633 -
635 TO 638 640 TO 816 818 820 821 825 828 TO 837 839 843 TO 868 870 TO
873 -
875 TO 1051 1053 1055 1056 1060 1063 TO 1072 1078 TO 1103 1105 TO
1108 1110 -
1111 TO 1286 1288 1290 1291 1295 1298 TO 1307 1309 1313 TO 1342 1344
1346 -
1348 1349 1351 TO 1394 1396 TO 1405 1408 TO 1433 1436 TO 1441 1443
TO 1463 -
1466 1468 1469 1484 1485 1488 TO 1531 1533 TO 1543 1546 TO 1552 1555
TO 1565 -
1572 TO 1574 1577 1578 1583 TO 1637 1639 TO 1645 1648 TO 1661 1664
TO 1824 -
1837 TO 1854 1859 TO 2029 2031 TO 2052 2055 TO 2074 2076 TO 2079 -
2083 TO 2230
MEMBER LOAD
1225 TO 1227 1230 1231 1233 1234 1239 1240 1243 1245 1250 TO 1252 -
1257 TO 1261 1286 1288 1290 1291 1295 1298 TO 1307 1309 1313 1314 -
1316 TO 1318 1320 1321 1331 TO 1342 1701 TO 1704 1805 TO 1808 1813
TO 1820 -
46. 46
1837 TO 1840 1899 1904 1909 1914 1919 1924 1929 1934 1939 1944 1949
1954 -
1959 1964 1969 1974 1989 1994 1999 2004 2009 2014 2019 2024 2101 2102
2152 -
2154 TO 2160 2178 2183 2188 2193 2196 2199 2202 2205 2224 2225 -
2230 UNI GY -3.68
285 TO 346 348 350 351 355 358 TO 367 369 373 TO 398 400 TO 402 520 TO
581 -
583 585 586 590 593 TO 602 604 608 TO 633 635 TO 637 755 TO 816 818
820 821 -
825 828 TO 837 839 843 TO 868 870 TO 872 990 TO 1051 1053 1055 1056
1060 -
1063 TO 1072 1078 TO 1103 1105 TO 1107 1669 TO 1700 1705 TO 1800 -
1841 TO 1848 1850 TO 1853 1860 TO 1863 1865 TO 1872 1874 TO 1877 -
1879 TO 1882 1884 TO 1898 1900 TO 1903 1905 TO 1908 1910 TO 1913 -
1915 TO 1918 1920 TO 1923 1925 TO 1928 1930 TO 1933 1935 TO 1938 -
1940 TO 1943 1945 TO 1948 1950 TO 1953 1955 TO 1958 1960 TO 1963 -
1965 TO 1968 1970 TO 1973 1975 TO 1978 1980 TO 1983 1985 TO 1988 -
1990 TO 1993 1995 TO 1998 2000 TO 2003 2005 TO 2008 2010 TO 2013 -
2015 TO 2018 2020 TO 2023 2076 2079 2084 2086 2090 2093 TO 2100 2105
TO 2110 -
2112 TO 2118 2120 TO 2151 2161 TO 2164 2166 TO 2169 2171 TO 2177 -
2179 TO 2182 2184 TO 2187 2189 TO 2192 2194 2195 2197 2198 2200 2201
2203 -
2204 2206 TO 2209 2211 TO 2214 2216 TO 2223 2226 TO 2229 UNI GY -14
LOAD 2 LOADTYPE Live TITLE LIVE LOAD
ELEMENT LOAD
1344 1346 1348 1349 1351 TO 1394 1396 TO 1405 1408 TO 1433 1436 TO
1441 1443 -
47. 47
1444 TO 1463 1466 1468 1469 1484 1485 1488 TO 1531 1533 TO 1543 1546
TO 1552 -
1555 TO 1565 1572 TO 1574 1577 1578 1583 TO 1637 1639 TO 1645 1648
TO 1661 -
1664 2025 TO 2029 2031 TO 2052 2055 TO 2074 2077 2078 2083 2085 2087
TO 2089 -
2091 2092 PR GY -4
LOAD COMB 3 COMBINATION LOAD CASE 3
1 1.5 2 1.5
PERFORMANALYSIS PRINT ALL
PERFORMANALYSIS PRINT ALL
PERFORMANALYSIS PRINT ALL
DEFINE ENVELOP
1 TO 3 ENVELOP 1
END DEFINE ENVELOP
START CONCRETEDESIGN
CODE INDIAN
UNIT MMS NEWTON
FC 20 ALL
FYMAIN 415 ALL
FYSEC 415 ALL
TRACK 0 ALL
DESIGN BEAM 285 TO 346 348 350 351 355 358 TO 367 369 373 TO 398
400 TO 402 -
520 TO 581 583 585 586 590 593 TO 602 604 608 TO 633 635 TO 637 755 TO
816 -
818 820 821 825 828 TO 837 839 843 TO 868 870 TO 872 990 TO 1051 1053
1055 -
48. 48
1056 1060 1063 TO 1072 1078 TO 1103 1105 TO 1107 1225 TO 1286 1288
1290 1291 -
1295 1298 TO 1307 1309 1313 TO 1342 1665 TO 1824 1837 TO 1854 1859
TO 2024 -
2076 2079 2084 2086 2090 2093 TO 2230
DESIGN COLUMN 168 170 TO 284 403 405 TO 519 638 640 TO 754 873
875 TO 989 -
1108 1110 TO 1224
DESIGN ELEMENT 1344 1346 1348 1349 1351 TO 1394 1396 TO 1405 1408
TO 1433 -
1436 TO 1441 1443 TO 1463 1466 1468 1469 1484 1485 1488 TO 1531 1533
TO 1543 -
1546 TO 1552 1555 TO 1565 1572 TO 1574 1577 1578 1583 TO 1637 1639
TO 1645 -
1648 TO 1661 1664 2025 TO 2029 2031 TO 2052 2055 TO 2074 2077 2078
2083 2085 -
2087 TO 2089 2091 2092
CONCRETETAKE
END CONCRETEDESIGN
UNIT METER KN
PERFORMANALYSIS PRINT ALL
PERFORMANALYSIS PRINT ALL
FINISH
52. 52
GRAPH FOR MAXIMUM LOADED BEAM
ANALYSIS RESULTS OF MAXIMUM LOADED BEAM NO. 2114.
Figure 4.8 Graph For The Bending Moment MZ Of Beam No 2114
Figure 4.9 Graph For The Shear Force FY Of Beam No 2114
Figure 4.10 Graph For The Shear Force FZ Of Beam No2114
53. 53
GRAPH FOR MAXIMUM LOADED COLUMN
ANALYSIS RESULTS OF MAXIMUM LOADED COLUMN NO. 733
Figure:4.11 Graph for the Bending moment MZ of column no 733
Figure:4.12 Graph For The Shear Force FY Of Column No 733
Figure 4.13 Graph For The Shear Force FZ Of Column No 733
54. 54
CHAPTER 5
ANALYSIS AND DESIGN OF BEAMS
5.1 GENERAL
Based on the analysis data from the software the beams
were designed using the limit state method of design from IS 456 : 2000
with aids from SP:16. The beam was designed in to singly reinforced
and doubly reinforced beam based on the moments, span and the nature
of the support.
5.2 ANALYSIS OF BEAM
5.2.1 ANALYSIS OF BEAM (2114) ANALYSIS REPORT FROM
STAAD Pro 2008
55. 55
5..3 MANUAL DESIGN OF BEAM
From the Figure of Reinforcement details of STAAD
Pro.2008 the maximum moment value of beam no.2114 should be taken .
5.3.1 PRELIMINARYDATA BEAM NUMBER (2114)
Maximum moment = 127 kNm
Size of the beam = 0.45 x0.3 m
Concrete mix (fck) = 20N/mm2
Characteristic strength, (fy) = 415 N/mm2
Factored moment, Mu = 1.5 x 127
= 190.5 kNm
Assuming 20mm dia of bars with clear cover of 25mm
Effective depth (d) = 450 - 25- 25/2
= 412.5mm
From sp 16 for fy 415 N/mm2 ; fck= 20 N/mm2
Mulimit = 0.138 x fck bd 2
= 140 .88 KN .m
Since Mu>Mu limit; Design a doubly reinforced section.
Mu-Mulim = 190.5-140.88
= 49.62KN.m
fsc = { 0.0035 (Xumax-d1)/(Xumax)}Es
= {0.0035(0.48x412.5)}-25/(0.48x412.5)}828105
= 611 N/mm2
But fsc>0.87 fy = 0.87x415
= 361.05 N/mm2
57. 57
Using 8mm diameter two-legged stirrups the spacing is
Sv = (0.87fyAsvd)Vus
= (0.87x415x2x50.26x412.5) / (12.95x103)
Sv = 1156.04mm
Sv >0.75d = 0.75x412.5
= 309.375mm
Adopt 8mm dia two-legged stirrups at 150mm c/c
5.3.4 REINFORCEMENT DETAILS OF BEAM NO. 2114
Figure 5.1 Reinforcement Details of Beam Number .2114
58. 58
CHAPTER 6
DESIGN AND ANALYSIS OF COLUMNS
6.1 GENERAL
Based on the analysis data from the software the columns
were designed using the limit state method of design from IS 456 : 2000
with aids from SP:16. Column is defined as an element used primarily to
support axial compression and with a height of at least three times of
its least dimension.
6.2 ANALYSIS OF COLUMN
6.2.1 ANALYSIS OF COLUMN 733 ANALYSIS REPORTFROM
STAAD Pro 2008
Table 7.1 Analysis of column number .733
59. 59
6.3 MANUAL DESIGN OF COLUMN
6.3.1 PRELIMINARY DATA OF COLUMN NUMBER 733:
Axial load =1011KN
Moment =7.95KN.m
Size of column = 0.3x0.3m
Concrete mix (fck) =20N/mm2
Characteristic strength(fy) =415N/mm2
Pu=1.5x1011 =1516.5KN
Mu=1.5x7.95 =11.925 KN.m
DESGIN CALCULATION:
Assume 25mm bars with 40 mm cover
d ’ = 40+12.5= 52.5mm
d’/D = 52.5/300
= 0.175
d’/D = 0.2
Pu/fckbd =((1516.5x103)/(20x300x300))
=0.842
Mu/fckbd = 11.925x106 / 20x330x3002
= 0.02
From chat 33of Sp:16
P/fck =0.14
P = 0.14x20
=2.8
60. 60
Ast = (Pbd)/100
Ast = (2.8x300x300)/100
Ast =2520mm2
Number of bars =ASt/((π/4)x202)
= 2520/((π/4)x202)
= 8 NOS
Provide 8NOS of 20mm dia bar, AS provided = 2520mm2
DESIGN OF TIES:
Diameter:
i. 5mm least
ii. ¼ x main bar diameter = ¼ x 20 =5mm
Adopt6mm dia bars becausewhich is the minimum rod available in market
PITCH:
i. least lateral dimension = 400mm
ii. 16 x dia of bar = 16x20 = 320mm
Adopta pitch of 320mm
62. 62
CHAPTER 7
DESIGN OF FOOTING
7.1 GENERAL
The design of the footing is done manually following the IS
456 : 2000 with aids to SP:16. The design is based on the maximum
axial load acting on the column and also the size of the column. The
type of footing designed is rectangular type. The axial load value is
taken from the STAAD Pro 2008 output.
7.2 DESIGN CALCULATION
7.2.1 DATA
Maximum axial load Pu=1011KN
Size of footing = 0.3X0.3m
Safe bearing capacity of soil at site is 250KN/mm2
SIZE OF FOOTING
Load of column =1011KN
vSelf – weight of footing (10%) =101.1KN
Footing area =P / SBC
=1112.1/(1.5x250)
=2.96m2
Proportion the footing area in the same area proportionas the side of
the column
63. 63
Hence (3x)x(3x) = 3m2
9x2 = 3
x2 = 0.33
x = 0.577
Short side of footing = 3x0.577
= 1.731m
Long side of footing = 3x0.577
= 1.731m
Adopta square footing = 2mx2m
Factored soil pressure at base is computed as
Pu = 1011/(2x2)
= 252.75KN/m2
Pu<(1.5x250) = 375KN/m2
Hence the footing area is adequate since the soil pressuredeveloped at the
base is less than the factored bearing capacity of soil
FACTORED BADING MOMENT:
Cantilever projection from both side face of the column
= 1/2(2-0.3)
= 0.85m
Bending moment at both side face of column
= 0.5xPuxL2
= 0.5x252.72x0.852
= 91.30KNm
64. 64
DEPTHOF FOOTING:
a) From moment considerationwe have
Mu = 0.138 fckbd2
91.30x106 = 0.138x20x300xd2
91.30x106 = 828d2
d2 = ((91.30x106) /(828))
d2 = 332.06mm
b) Shearforce per meter width
Vul = Pu(l-d)
= 252.775(850-d)
Assuming the shear strength of ﺡc= 0.36 for M20 grade concrete with
nominal percentage of reinforcement, Pt=0.25
0.36 = 252.75(850-d)/1000xd
Solving,
d = 350mm
Overall depth, D = 400mm
REINFORCEMEN IN FOOTINGT: (BOTHDIRECTION)
ASt = 0.5fck/fy[1 − √1 − (
4.6𝑀𝑢
𝑓𝑐𝑘𝑏𝑑2
)]bd
ASt = 0.5X20/415[1 − √1 − (
4.6𝑋91.30𝑋10^2
20𝑋1000𝑋350^2
)]x350x100
Ast = 756.8mm2
65. 65
Spacing, SV = (1000x
𝜋
4
𝑥(16)^2)/756.8
= 260mm
Solving:
Ratio of long to short side β = (2/2)=1
Reinforcements in central band width of 1.85m is
= (1.85/β+1)Ast
= (1.85/2)5702
= 5274.3mm^2
Main reinforcement = (0.0012*2*1000*400)
= 960mm^2
Check for shearstress:
Vu = pu(l-d)
= 252.75(850-350)
Vu = 126.3KN
(100Ast/bd) = (100x5275/350x1000)
= 1.50
Refer table 19 0f IS:456-2000 and read out the permissible shear stress.
(ksﺡc ) = (1.2x0.72)
= 0.864N/mm2
Since ﺡv<Ksﺡc , shear stresses are with in the safe permissible limits.
67. 67
CHAPTER 8
ANALYSIS AND DESIGN OF RCC SLABS
8.1 GENERAL
Based on the analysis data, R.C.C slab was designed using
the limit state method of design from IS 456 : 2000 with aids from SP :
16. The slab was designed in to two way continuous based on the span
and the nature of the support.
8.2 PRELIMINARY DATA:
LyLx =6.705.48 < 2
=1.22 < 2
Hence slab is to be Designed as two way slab for balanced
section design constants are Qu=2.79̈́%, Ast=0.958%, Madulation factor =0.98 ,
Base value=26.
Normally two way slabs are governed by stiffness and will be
under reinforced. Hence let us provide 0.6% Ast instead of 0.958% , M F for
0.6%, Ast=1.12
DEPTHFOR STIFFNESS
Minimum depth for stiffness
d =span / B.V x M.F
=5480 / 26x1.12
=188mm
Using 10 dia bars and 15mm clear cover
D =188+15+(10/2)
=208mm
68. 68
Say, D =210mm
D =190mm
LOADING
Consider 1000mm breadth of strip for design purpose
Impose load =4.00KN/m2
Floor finish =1.00KN/m2
Self weight =1x1x0.2x25
=5KN/m2
Total =10KN/M2
Factored load , Fd =10x1.5
=15KN/m
FACTOREDMOMENT,Mud
Forcorner panel two adjacent edges are discontinuous
Refer table 26of Is codefor ly/lx=1.22
αx=0.045; αy=0.035;-αx = 0.06; - αy=-0.047
The Factored moment along shorter span
Mu(lx) =α x w lx
2
=0.045x15x5.482
=20.2KN.m
The Factored moment along longer span
Mu(ly) =α y w ly
2
=0.035x15x5.482
=15.7KN.m
The Factored moment along shorter span
- Mu(lx) =- α x w lx
2
=0.06X15X5.482
69. 69
=27KN.m
The Factored moment along longer span
-Mu(ly) =-α y w ly
2
=0.047X15X5.482
=21.1KN.m
EFFECTIVE DEPTHFOR ,Mud(maximum)
Consider max factored moment for finding depth of slab
Mud(max) =Qubd2
d =27x106/2.79x1000
=98mm
FINAL DEPTH
Consider depth required for stiffness and factored moment, adopt greater
value
Final d=190mm
D=210mm
REINFORCEMENT
Mu(limit) =Qubd2
=2.79x1000x1902
=100.71KN.m
But Mud(max) < Mu(limit), The section is under reinforced
Minimum Area steel
Minimum area of steel =0.12% of Ag
=0.12x1000x210100
=252mm2
71. 71
Sv =(1000/(π/4)102)/412
Sv =190mm
Ast along longerspan Ast(lY) (-ve)
Ast =0.5x20/415[1 − √1 − (
4.6∗21.1𝑥106
20𝑥1000𝑥180^2
)]1000x180
Ast =338mm2
Sv =(1000/(π/4)102)/338
Sv =230mm
DISTRIBUTION STEEL
Minimum Steel =252mm2
Spacing of 8mm bars =(1000/(π/4)82)/252
=199mm
Says Sv =190mm
These rods are provided on all the four edges strip portion at bottom
face of slab These are also provided as distributions for all negative rods at
top.
MIDDLE STRIP AND EDGE STRIP
Refer clause c.1.2 of Is code
Middle strip for shorter span =3/4xly
=3/4x6700
=5025mm
Edge strip for shorter span =1/8xly
=1/8x6700
=837.5mm
Middle strip for longer span =3/4xlx
=3/4x5480
72. 72
=4110mm
Edge strip for longer span =1/8xlx
=1/8x5480
=685mm
Main reinforcement is provided only in middle strip.In all the edge
stripes, minimum steel is provided, minimum steel is also used as distributor for
the negative rods at top.
CHECK FOR SHEAR
It is sufficient to check the shear along shorter span only spacing of
10mm dia bar after 50% curtailment at support
=410x2
=820mm
Ast available at support=Astx1000 / spacing
=78.54x1000 / 820
=95.7mm
% Ast =Ast x100 /bd
=0.05%
Thereforeﺡc =0.36N/mm2
K for 200mm thick slab =1.2
Permissible shear stress = k ﺡc
=1.2x0.36
=0.43N/mm2
½ ﺡc (max) =1/2 x 1.8
=0.9N/mm2
Shear force at support =0.6 FdL
=0.6x15x5.48
=49.32x103 / 1000x190
73. 73
=0.25N/mm2
Since ﺡv< k ﺡc and 1/2 ﺡc (maximum), Slab safe in shear.
CHEAK FOR DEFLECTION
Consider shorter span only
Ast =Astx1000 / spacing
=78.54x1000 / 410
=191mm2
% Ast =Ast x100 /bd
=191x100 / 1000x190
=0.13%
M.F for 0.13% of steel =2.0
d required for stiffness = span/ B.VxM.F
=5480/26x12
=105mm
But, d actually provided is 190 > 105mm
Therefore safe
75. 75
CHAPTER 9
DESIGN OF STAIRCASE
9. GENERAL
Based on the analysis data, the stair case was designed using
the limit state method of design from IS 456 : 2000 with aids from SP :
16. The stair case was designed as dog legged type based on the
utilization of the space available.
9.1 PRELIMINARY DATA:
Type = Dog legged stair
Rise =150mm
Thread =300mm
Height =3.2m
MATERIALS M20 grade
Fe 415
Height of per flight =3.2/ 2
=1.6m
No of steps per flight =1.6 /Rise
=1.6 /0.15
= 11nos
No of steps per flight 11-1 =10nos
Assume, width of stair case =1.5m
Centre flight horizontal length=10x0.3
76. 76
=3
Landing length =6-3
=3/2
=1.5m
DESIGN OF STAIR
Effective Length
Assume, Bearing of wall / landing beam = 230mm
Leff = c/c distance of the Bearing
=6+0.23=6.23m
Depth
Min. thickness of waist slab = 80mm
= 40xLeff
= 40x6.23
= 249.2
D = 250mm
d = 250-20-10/2
effective depth d = 225mm
LOAD CALCULATION
Dead load steps
= (1/2x0.15x.3)25
= 0.5625kn/m2
i. D.L of waist slab
a) Waist slab @ inclined position
W=1x1.5x0.250x25
=9.375kn/m2
b) D.L of waist slab horizontal
=wx√T2XR2/T
77. 77
=9.37X√0.32X0.152/0.3
=10.47KN/m2
c) D.L of floor finish
=0.05x1.5x1x22
=1.65 KN/m2
ii. Live load on the stairs =5KN/m2
Consider aseffective loading =5x1.35
=6.75KN/m2
Total Dead load, w =0.56+10.47+1.65
=12.68KN/m2
Live load = 6.75KN/m2
Total load = 19.43KN/m2
Ultimate load, wu = 1.5x19.43
wu = 29.14KN/m2
Mu= WuxL2/8
= 29.14x6.232/8
Mu = 141.37KN.m
Mu limit = Qubd2
= 2.7x1000x2252
Mu limit = 136.6KN.m
Mu limit>Mu, Hence the Design is safe
ASt = 0.5fck/fy[1 − √1 − (
4.6𝑀𝑢
𝑓𝑐𝑘𝑏𝑑2
)]bd
= 0.5x20/415[1 − √1 − (
4.6∗141.37106
20𝑥1000𝑥225^2
)]
Ast = 2222.9mm2
Astmin =0.12% of G.A
78. 78
= 0.12/100X1000X250
Astmin = 300mm2
Using 12mm diameter bar
No. of bars =2222.9/(π/4)122
= 19.65
Spacing of bars =1000/19.65
=50.89mm
To provide 12mm dia @ 60 mm c/c distance
DISTRIBUTION STEEL
Use 8mm diameter
Number of bars =300/(𝜋/4)82
=5.96
Spacing =1000/5.96
=167.7mm
To provide dia 8mm distribution steel @170 mm c/c distance
80. 80
CONCLUSION
The main thing known from the paper is that the structure should
not have any offsets. If the building is not symmetrical special provisions
should be taken to make to overcome the problems.
In this project, static analysis is done by using the STAAD
Pro 2008. We have taken a three storied framed structure and analyzed
the structure for the shear and bending moment. Based upon the results
obtained the structure is designed manually in critical sections using limit
state method of design. The critical sections were found from the output of
STAAD Pro 2008 and based on the maximum moments and shear force
obtained, the sections are revised economically. When we compared the
manual design with STAAD Pro results, the method of analysis using
STAAD Pro 2008 gives accurate results than the manual design and it is a
time consuming process. After the analysis and design of Structure using
STAAD Pro 2008, quickly we have concluded whether the structure may
be failure or not.
This project shows lights upon the effective usage of the
software in the analysis of the structure for dead load and live load
combinations and thorough knowledge in analysis and designing of Multi
storied Structure.
81. 81
REFERENCES
Welfare & Associates ,at(el 1980) says, “when marketers use the word
“design” they usually refer advertising , point of purchase materials,
packaging labels, and annual report
IS : 456 – 2000 Indian standard code of practice for plain and
reinforced concrete (fourth revision), bureau of Indian standards, New
Delhi.
IS : 456 – 1978 Design aids for Reinforced Concrete. SP – 16 Indian
standards institution, New Delhi.
IS –NBC -2005: National Building Code of India Bureau of Indian
Standards, New Delhi.
IS:875-1987 (PART I) , “ Unit weights of materials”, Bureau of Indian
standards, New Delhi
IS:875-1987 (PART II) , “ Design Loads for Building and structures,
Impose loads”, Bureau of Indian standards, New Delhi