BY HANI MAHMOOD AL-SAHI (20052126) OTHMAN SAFDAR (20050032)
Supervised by Dr. Esmat Kameshki
Abstract by Othman 2
Designing of beams, columns, base plates and connections form the core of elementary steel design. All these topics have been covered in this project and it is hoped that the readers will find this report to be useful. The given project is the design of a single storey, two-bay steel building frame. According to the requirements, this report
furnishes the design and calculation of laterally supported and laterally unsupported beams, a column, the column base plate and bolt connection. The practice code which has been followed is BS 5950 Part 1:2000. The calculations have been verified by softwares “StaadPro” and “ProSteel 5”.
Table of Contents 3
1.
Abstract …………………..........................
1
2.
Introduction ……………….........................
4
3.
Laterally Supported Beam...........................
8
4.
Laterally Unsupported Beam …………...
11
5.
Column ………………………………….
14
6.
Base Plate ……………………………...
16
7.
Connection ……………………………....
18
8.
Conclusion…………. …………………...
22
9.
Appendix ……………………………….
23
Introduction by Hani & Othman 4
General Introduction: By Hani This project is a steel design 1 project, which collect all the design procedures taken during the course. The project gives the chance for the students to practice design procedures and using tables and codes. The B.S. 5950 1 – 2000 code was used. Beams: By Othman Beams are members that carry loading primarily in bending. They span between supports or connections. Beams are available in many varieties which differ in the shape of cross-section. A common type is an I-Section. Some more types are shown in the following figure:
5
Under the action of loads, the beam may buckle, which means the shape of the member deforms. This appears something like this: Lateral-Torsional Buckling: If an I-section of beam is subjected to vertical loading, it may move laterally with the beam. Since beam will try to resist this movement, its shape will slightly distort. Due to bending, the flange of the beam will be in compression and therefore buckle sideways. And because the bottom flange will resist this sideways buckling, the section will twist. This entire action is known as Lateral-Torsional Buckling and it is shown in this figure:
6
Laterally-Supported Beam: In context of the above discussion, a beam which does not laterally move nor rotate is known as LaterallySupported Beam. It depends upon the kind of restraint provided at the supports as well as on the loading. If, for example, beam is supporting a slab, then this beam will be laterally-Supported beam. Laterally-Unsupported Beam: However, if a point load is acting on the beam, then it will exhibit lateral-torsional buckling and therefore such a beam will be called Laterally-Unsupported. If the beam is restrained at intervals, then lateral torsional buckling will take place between the restraints and intermediate supports.
Columns: by Hani A column in structural engineering is a vertical structural element that transmits, through compression, the weight of the structure above to other structural elements below. In simple constructions it appears that columns are not subject to moment. But, in most cases there is bending moment due to the eccentricity of the shear load from the beam. The place where beam or roof truss is sits or supported on column can be assumed that the load –Reactions-is transmitted to axial load on the column.
7
Connections: by Hani Connections are joints used to transfer the load from part of the structure to other one. The connection include connectors such as: bolts, pins, rivets or welds. The type and arrangement of the connectors depend on the force being transferred and on the member connectors. But, during designing the connections minimum cost should be considered. On this project the only connection will be used is the pre-loaded bolts. Base Plates: by Hani
Are the endplate of a column, which rests on the supporting substructure surface. Baseplates provide the interface between the columns and the foundation system. The baseplates are used to provide both a smooth and level bearing surface for the columns and to distribute the column load into the foundation. The baseplates are set over anchor bolts, previously cast into the foundation, and then leveled. The leveled baseplates are then grouted into position to ensure a positive load transfer from the columns to the foundation.
Laterally Supported Beam by Othman 8
Design the following beam assuming it is laterally supported along its entire length. Use steel grade S275.
Shear and moment diagram are provided at the appendix Section Data: (UB457x191x89) D=463.4 mm t= 10.5 mm T=17.7 mm b/T=5.42 d/t=38.8 rx=19 cm ry=4.29 cm Zx=1770 cm3 Sx=2014 cm3 A=114 cm2
9
Section Classification (UB457x191x89)
T11
b/T ≤ 9ε py=265 N/mm2
T9
ε= (275/265)0.5 =1.02
T11 (note b)
b/T ≤ 9ε 5.42≤9.18 d/T ≤ 80ε . 38.8≤81.6
Therefore the entire section is plastic
Shear Capacity
4.2.3
Pv=0.6pyAv=0.6xpytD=773.64 KN
Fv(=229.06 KN) < 0.6Pv( =464.184 KN) Therefore Section is OK in shear
Moment Capacity
4.2.5
Mc=pySx=265(N/mm2)x2014(cm3)=533.71 KN.m Mc=1.2pyZx=562.86 KN.m
Mc( =533.71KN.m) > Mmax( =529.701)
Mc < 1.2pyZx
Therefore section is OK in moment.
Serviceability Check: 5wi L4/ 384 E I < Span/200 5.4 mm
2.5.4
10
Check by ProSteel5
Laterally Unsupported Beam by Othman 11
Design the following beam assuming it is laterally unsupported along its entire length. Use steel grade S275.
Shear and moment diagram are provided at the appendix Section Data: (UB 610x305x179) D=620.2 mm t= 14.1 mm T=23.6 mm b/T=6.51 d/t=38.3 ry=47.07 cm Sx=5550 cm3
Section Classification py265 N/mm2 ε=1.02
T11
12 b/T ≤ 9ε d/t ≤ 80ε Section is Plastic. Effective Length
T13
LE=11.04 mm U=0.866 βw=1
Section tab;le
pb=108.7 N/mm2
4.3.6.9
Λ=156.2 V=0.788
T16
X=27.2
4.3.6.7
λ/x=5.64 Mb=pbxSx=603.294 KN.m > Mmax Therefore section is OK with respect to buckling resistance Shear Capacity 0.6pytD = 1390 KN > 229 KN Therefore Section is OK in shear. Deflection Check 5wi L4/ 384 E I < Span/200 5.4 mm
T19
13
Check by ProSteel 5
Column by Hani 14
Design the following unbraced column using steel grade S275.
Section Data: (UC 152x152x30) D=157.6 mm t= 6.5 mm T=9.4 mm b/T=8.13
d/t=19 ry=3.83 cm rx= 6.76 mm
Sx=248 cm3
Section Classification py265 N/mm2
ε=1.02
T11
15
Section Classification (UB457x191x89)
T11
b/T ≤ 40ε 8.13 < 40.8 d/t ≤ 40ε 19 < 40.8
Therefore both the web and flange are semi-compact.
Axis of Buckling LEX=600
T22
Λx = 88.76 pcx = 163.48 N/mm2
T24 LEY = 600 Λy = 156.66
pcy = 63,37 N/mm2 Pc=Agxpcy = 243.86 KN Therefore section is safe and economical.
4.7.4 (a)
Base Plate by Hani 16
Design the column Base plate.
Section Classification (UB152x152x30) T = 9.4 mm D = 157.6 mm B = 152.9 mm t = 6.5 mm Assume the base plate is on ground which has 30 N/mm2 strengh Abc ≥ (229.06 x 103)/(0.6x30) = 1.27x104mm2 Therefore Aeff=1.27x104 [(B+2C)(D+2C)]-[(B+2C)-(2C+t).(D-2(C+T)] = [(152.9+2C)(157.6+2C)]-[(152.9+2C)-(2C+6.5)].(157.62(C+9.4)] C= 9.38 (simplifying the above equations and using quadratic equation) D+2C = 157.6+(2x9.38)=177mm B+2C = 152.9+(2x9.38) = 172 mm
180x180
17 Therefore tp = c[3w/Pyp]0.5 = 9.38[3(0.6x30)/275]=2mm Therefore Baseplate: 180x180x2
Design of Connection by Hani 18
Grade 8.8 non-preloaded/ordinary bolts In clearance hole.
Assuming that there is thread, so we take the area of shank and assuming it is M16 of grade 8.8 As= 157 mm2
T4.22
Shear Capacity = Ps = ps.As
6.3.2.1
ps = 375
N/mm2
Ps = 375
N/mm2
T30 . 157x10-3 = 58.88 KN for single shear
Ps = 58.88x2 = 117.76 KN for double shear Bearing Capacity of Bolts Pbb = dtppbb =
16x10x1000x10-3=160
6.3.3.2 KN
Bearing Capacity of Connected Portion Pbs
=
kbsdtppbs
< 0.5
= 1.0x16x10x460x10-3 = 73.6 KN
T31 T32
19
Assume e=2d=32 mm 0.5kbsetppbs = 73.6 KN Therefore Pbs = 73.6 KN Therefore governing capacity = 73.6 KN
Lap length No. of bolts required = 229.06/73.6 = 4 bolts Bolt Spacing = Smin = 2.5d=40mm
6.2.1
Smax = 14t = 140 mm End Distance (e)
6.2.2
emin= 1.25D = 22.5 mm
T29
emax= 11tε = 110 mm ε=(275/py)0.5 = 1
Checking e and s: (Smax = 140mm) > (S=76 mm) > (Smin=40mm)
S is acceptable (emin= 110) >(e= 32 mm) > (emax=225mm) e is acceptable
T9
20
Take: e = 35mm S = (290-(2C35))/3 = 74 mm Therefore 4M16 Grade8.8
Non-preloaded bolts required.
Conclusion by Hani and Othman 21
At the end of this project, we hope that we have provided a good idea about the design of the given project.
Software like “StaadPro” and “Prosteel” were used for shear and bending moment diagram and design checking respectively. The economical part was considered in the project. We have learned a lot from this project which is definitely going to help us in the future.
Appendix 22
Here is the calculation of the applied load:
23
Shear Moment Diagram using StaadPro
24
Trials Carried out while selection of sections:
Laterally Supported Beam: UB 457x191x 82
UB 457x191x 74
Laterally Unsupported Beam: UB 533x210x122 UB 610x305x149 UB 686x254x170
Column: UC 203x203x46 UC 152x152x23
