10. Load Combination
1.4 Dead
1.2 Dead+1.6 Live+0.5 Liveroof
1.2 Dead + 1.6 Liveroof + Live
(1.2 + 0.2 SDS ) Dead + ρ QE + Live + 0.2 Snow
(0.9 – 0.2 SDS) Dead + ρ QE
For General Load
Consideration
For Seismic
Load
Consideration
12. Method of Analysis
Equivalent Lateral Force (ELF) procedure is selected to
analyze the structure, based on the structure’s –
Seismic design category
Structural system
Dynamic properties and
Regularity
23. Torsional Irregularity
Level
Applied
force
Avg
deflection
Max
deflection drift Max drift
Ratio=max/avg
Drift Torsional irregularity
Roof
226.3 3.18 3.400 0.17 0.100 0.59 Less than 1.2, OK
8
218.6 3.01 3.300 0.11 0.300 2.73 Less than 1.2, OK
7
172.6 2.9 3.000 0.3 0.200 0.67 Less than 1.2, OK
6
130.7 2.6 2.800 0.3 0.300 1.00 Less than 1.2, OK
5
93.2 2.3 2.500 0.3 0.400 1.33 Less than 1.2, OK
4
60.5 2 2.100 0.4 0.500 1.25 Less than 1.2, OK
3
33.3 1.6 1.600 0.5 0.400 0.80 Less than 1.2, OK
2
12.6 1.1 1.200 1.1 1.200 1.09 Less than 1.2, OK
24. Irregularities
There are two kinds of irregularities:
Horizontal Irregularities
Vertical Irregularities
There are five types of Horizontal irregularities as follows:
Torsional and Extreme Torsional
Reentrant Corner
Diaphragm Discontinuity
Out-of-plane Offset
28. • There are no discontinuities of the lateral force resisting path in our
system.
The resisting path is continuous through all the story of the building.
No out of plane offsets irregularity was found.
30. • Lateral resisting element is parallel throughout our system.
Nonparallel system irregularity was not found.
31. There are five Vertical Irregularities:
Stiffness-Soft story and Stiffness- Extreme Soft Story
Weight
Vertical Geometric
IN-plane discontinuity in vertical lateral force resisting element
Discontinuityin lateral strength (Weak story and Extreme weak story
33. Weight (mass) Irregularity
This irregularity exists where the effective mass of any story is more than
150% of the mass of an adjacent story. A roof that is lighter than the floor
below need not be considered.
No weight irregularities is found as weight of the given story is less than 150 %
of the effective mass of adjacent sides
34. Vertical Geometric Irregularity (Type 3)
Vertical geometric irregularity
exists where the horizontal
dimension of the seismic force
system in any story is more than
130% of that in the adjacent story.
Since there are no geometric
irregularities either in moment or
braced frame, no vertical geometric
irregularity were found
35. In-Plane Discontinuity in Vertical Lateral Force
Resisting Element Irregularity (Type 4)
This irregularity exists where an
in-plane offset of the lateral force
resisting elements is greater than
the length of those elements.
Since there are no offset of the
lateral force resisting element,
no irregularity was found.
38. Steel member Design
Special Moment Frames
Column
Column depth
Column Flange
check for buckling of flange
check for buckling of web
Other
Probable moments at plastic hinge
Shear at plastic hinge
Beam Vs column strength
Strengths of panel zone
Beam shear strength
Continuity plates
Beam
Beam depth
Beam Weight
Beam Flange
Clear span vs beam depth ratio
check for buckling of flange
check for buckling of web
41. Steel member Design
Eccentric Braced Frames
Size of the link
determine if the axial load is significant
shear check capacity
check link length limit
check link rotation angle
check link slenderness
Check the beam outside the link
compression capacity
moment capacity
check interaction equation
Brace Design
over strength factor
check slenderness for ductile members
check compression capacity
check flexural capacity
check interaction
