Description

EC8-DCH

ASCE-SMF

Restrictions on the use of Cross section

For q higher than four only class 1 sections are permitted to be used

Sections must be compact

Seismic load reduction factor

q equal to 5α_u/α₁

R equal to 8

Energy dissipation philosophy (significant inelastic deformation)

Given by ductility class high

Given by special moment resisting frames, and are anticipated to undergo

Overstrength factor

Obtained from ratio of plastic moment of columns to beams

Restricted to 3

Local ductility

Plastic hinge rotation is restricted to 35 mrad

Plastic hinge rotation is restricted to 30 mrad with inter-storey drifts to 0.04 radians

Strength checks for Beams

$\frac{M_{E,d}}{M_{pl,Rd}}\le 1.0\text{}\text{}\text{}\text{}\text{}\text{}\text{},\frac{N_{E,d}}{N_{pl,Rd}}\le 0.15,\frac{V_{E,d}}{V_{pl,Rd}}\le 0.5$

Only strength checks as per AISC/LRFD are required

Ratio

$\frac{q}{\Omega }=?$

$\frac{R}{\Omega }=\frac{8}{3}=2.67$

Strong column weak beam (SCWB) philosophy

${\displaystyle \sum M_{Rc}}\ge 1.3{\displaystyle \sum M_{Rb}}$

$\frac{{\displaystyle \sum M_{pc}^{*}}}{{\displaystyle \sum M_{bc}^{*}}}\ge 1.0$ , Columns should have sufficient flexural strength

Non-dissipative members such as columns

$N_{Ed}=N_{Ed}{}_{,G}+1.1{\gamma }_{ov}\Omega N_{Ed}{}_{,E}$ Math_33##Math_34#

Verification of strength with loads computed from special load combinations having Ωo