This document reviews the behavior of special moment resisting frames (SMRFs) and intermediate moment resisting frames (IMRFs) during earthquakes. SMRFs are designed to withstand significant inelastic deformations in high seismic regions, while IMRFs are intended for moderate deformations in low to mid seismic areas. SMRFs have stricter design requirements than IMRFs. Analysis showed that SMRFs have greater collapse capacity and longer progressive collapse duration than IMRFs, reducing risk of structural sidesway collapse by 33.4% compared to IMRFs. The use of SMRFs also increases required column longitudinal reinforcement by 40% over IMRFs.

2. BEHAVIOR OF SMRF AND
IMRF RC BUILDINGS
DURING
EARTHQUAKES - A
REVIEW
Prepared by: Muhammad Abrar
MCE-203017
Supervised by: Prof. Engr. Dr. Majid Ali

3. CONTENT
 Description
 Comparison between different type of
Steel Moment Frames
 Conclusion

4. DESCRIPTION
 Type of Research
Special moments resistance frame and intermediate moment
resistance frame
 Research Question
What is SMRF & IMRF and how the selection is made?
 SMRF (Special Moment-Resisting Frame)
Special proportioning and detailing requirements are critical in
resisting strong earthquake shaking with substantial highly
inelastic behavior. These moment-resisting frames are called
Special Moment Frames because of these additional
requirements, which improve the inelastic response
characteristics of these frames in comparison with less
stringently detailed Intermediate and Ordinary Moment Frames.
SMRF/SMF expected to withstand significant inelastic
deformations, require use of prequalified connections per AISC
or verified with testing, must sustain inter-story drift angle of at
least 0.04 radians and typically used in mid/high-seismic
regions.

5. DESCRIPTION
 IMRF (Intermediate Moment-Resisting Frame)
Proportioning and detailing requirements are
critical in resisting strong earthquake shaking with
substantial moderately inelastic behavior. These
moment-resisting frames are called Intermediate
Moment Frames because of these additional
requirements, which improve the inelastic response
characteristics of these frames in comparison with
less stringently detailed Intermediate and Ordinary
Moment Frames.
IMRF expected to withstand moderate inelastic
deformations, require use of prequalified
connections per AISC, must sustain inter-story drift
angle of at least 0.02 radians and typically used in
low/mid-seismic regions.

6. COMPARISON BETWEEN DIFFERENT
TYPE OF STEEL MOMENT FRAMES
 When it comes to moment resisting
frames, there are three types of
frames defined in the code ordinary
moment frames (OMRF), intermediate
moment frames (IMRF) and special
moment frames (SMRF). These are
listed in the table below along with
their Response Modification
Coefficient (R-value), Overstrength
Factor (Ωo), and Deflection
Amplification Factor (Cd) per ASCE 7.

7. Cont.Frame
Type
R-Value Ωo Cd
OMRF 3.5 3 3
IMRF 4.5 3 4
SMRF 8 3 5.5

9. Cont.
OMRF expected to withstand limited inelastic
deformations, doesn’t require use of
prequalified connections per AISC, not required
to be tested and typically used in non/low-
seismic regions. IMRF expected to withstand
moderate inelastic deformations, require use of
prequalified connections per AISC, must
sustain inter-story drift angle of at least 0.02
radians and typically used in low/mid-seismic
regions. SMRF expected to withstand
significant inelastic deformations, require use of
prequalified connections per AISC or verified
with testing, must sustain inter-story drift angle
of at least 0.04 radians and typically used in
mid/high-seismic regions.

10. CONCLUSION
 Based on the IDA results, SMRF showed
greater collapse capacities, while IMRF
show smaller values.
 The role of SMRF in preventing the
structural sidesway collapse was
stronger in specified range of collapse
capacities. For instance, SMRF had the
greatest impact on preventing sidesway
collapse. For example, SMRF reduces
the risk of collapse 33.4% compared with
IMRF.

11. CONCLUSION
 Progressive sidesway collapse durations
of SMRF were longer than those of
IMRF. For example, for an average
progressive sidesway collapse, durations
are 25.6 and 15.8 for SMRF and IMRF
respectively. Also, the results showed
that SMRF collapse duration was 1.6
times that of IMRF.
 By using Special Moment Resisting
frames the longitudinal reinforcement
required in columns is increased by 40 %
as compared to Intermediate Moment
Resisting Frames.

12. AKNOWLEGEMENT
I would like to thank Engr. Prof. Dr.
Majid Ali for his kind support and
guidance.

13. Thank You