Project 3 - Building design for seismic effects

CVEN 557Structural Design for Seismic

EffectProject Assignment

Group 02May 2016

Presented by: Nahid Farzana, Dinesha Kuruppuarachchi, Kapil Adhikari

Elevation view

Plan view

Seismic Design Category

Risk Category & Importance Factor

Redundancy Factor Selection

Seismic Lateral System

Gravity LoadLevel Dead Load

(kip)Live Load

(kip)Total Load

(kip)Roof 1586.88 263.5 1851

8 1535.9 658.75 2195

7 1535.9 658.75 2195

6 1535.9 658.75 2195

5 1535.9 658.75 2195

4 1535.9 658.75 2195

3 1535.9 658.75 2195

2 1552.7 658.75 2211

Gravity load Tributary area on Moment Frames

Gravity load Tributary area on Braced Frames

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

ConsiderationFor Seismic

Load Consideratio

n

Selection of Analysis Procedure

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

Story Shear Calculation for moment frame

Story Shear Calculation for braced frame

Seismic Lateral Load Distribution

Modeling Consideration

Modeling Consideration

Moment Frame analysis

Deflected Moment Frame under Seismic Load

Unit Load Applied on Moment Frame

Stiffness and K matrix

Stiffness of frame = 1/ Deflection

Shear Force Calculation from StiffnessShear Force is calculated under following two condition:

Maximum Deflection

Torsional Irregularity

LevelApplied 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, OK8 218.6 3.01 3.300 0.11 0.300 2.73 Less than 1.2, OK7 172.6 2.9 3.000 0.3 0.200 0.67 Less than 1.2, OK6 130.7 2.6 2.800 0.3 0.300 1.00 Less than 1.2, OK5 93.2 2.3 2.500 0.3 0.400 1.33 Less than 1.2, OK4 60.5 2 2.100 0.4 0.500 1.25 Less than 1.2, OK3 33.3 1.6 1.600 0.5 0.400 0.80 Less than 1.2, OK2 12.6 1.1 1.200 1.1 1.200 1.09 Less than 1.2, OK

IrregularitiesThere 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

Reentrant corner irregularity (type 2)

• There are no reentrant corners in our system. There is no reentrant irregularity

Out of Plane Offsets Irregularity (Type 4)

• 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.

Nonparallel Systems-Irregularity (Type 5)

• Lateral resisting element is parallel throughout our system.Nonparallel system irregularity was not found.

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

Stiffness-Soft Story Irregularity (Type 1a)

Stiffness-Soft Story Irregularity (Type1b)

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

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

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.

Steel member Selection

Beam – W 24 x 131Column -W 14 X 500

Steel member Design

Steel member DesignSpecial 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

Sample Calculations

Steel member Design

Eccentric Braced Frames - Link

Steel member DesignEccentric 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

Sample Calculations