Seismic Response of Laterite Masonry Structures
Date
2013
Authors
Unnikrishnan, Sujatha
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Abstract
Laterite is the most favored masonry material in south-west coastal areas of India due to
its availability in abundance. However, not much research has been carried out so far on
the structural performance of laterite masonry. The studies addressing the seismic
performance of laterite masonry buildings are almost nil and hence there is a need for
research in this area.
The strength and elastic properties of laterite masonry are influenced by the individual
properties of laterite blocks and mortar used and the nature of bond between them.
Experimental investigations were carried out on the strength characteristics of laterite
blocks, cement mortar specimens and stack-bonded laterite masonry prisms under
uniaxial compression. From these studies laterite masonry may be classified as weak-soft
unit and strong-stiff mortar masonry. Stack bonded laterite masonry prism was modeled
using commercially available finite element software and analyzed to understand the
stress distribution pattern. Parametric studies were also conducted.
In south-west coastal areas of India masonry structures are normally box-type structures
with either a light roof or a rigid roof. Efficiency of different types of seismic
strengthening measures like lintel band, roof band etc. were studied on both these types
of structures. A method of reinforcing laterite masonry with vertical reinforcement called
‘containment reinforcement’ has also been tried. Different configurations of box-type
laterite masonry structures with these strengthening measures were modeled. Free
vibration studies were conducted to find the natural frequencies and mode shapes of boxtype laterite masonry structures without and with roof. Response of single storeyed boxtype laterite masonry structures, to El-Centro acceleration input was obtained using timehistory analysis. The effect of strengthening factors like lintel band, roof band and
containment reinforcement on the natural frequencies, mode shapes and time-history
responses were analyzed. Responses of some of these structures to Kobe and Koyna
accelerations were also studied
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Keywords
Department of Civil Engineering, Laterite, box-type structure,, natural frequency,, mode shape, seismic response.