Ductility often governs the design of structures in seismic zones, while mo
notonic punching shear strength governs the design of flat-plate structures
irt nonseismic zones. Because the ductility of concrete increases as stren
gth increases, high-strength lightweight concrete (HSLW) located in low to
moderate seismic zones can be used to enhance ductility, energy dissipation
, and seismic energy.
Six interior slab-column connections were tested under simulated earthquake
-type conditions. Loading was investigated to examine the effect of using H
SLW concrete. Of the six specimens studied, two slabs were made of 70 MPa c
oncrete, two slabs were made of 35 MPa normal-strength lightweight (NSLW) c
oncrete, and two were made of 35 MPa normal-strength normal aggregates (NSN
W) concrete. The steel reinforcement ratios were 0.5 and 1% for the three t
ypes of concrete,
Under seismic loading, HSLW concrete slabs showed a better performance in g
eneral than the other two types of concrete. Specimens made of NSLW and NSN
W concrete failed at a drift lower than that of HSLW. A higher displacement
after initial failure was sustained by HSLW as compared with the other typ
es of concrete. The results indicated that HSLW concrete had a higher ducti
lity compared with NSLW and NSNW concrete. The load capacity degradation of
HSLW concrete indicated superior energy dissipation compared with NSNW con
crete. The ACI code recommendations for semilightweight concrete should be
examined further to reflect the high strength and ductility behavior of HSL
W concrete. A reduction factor of 0.90 is more appropriate for HSLW concret
e than the current 0.85 recommended for lightweight concrete.