Abstract:
Low-rise buildings are susceptible to damage from factors like poor design or construction
quality, inadequate supervision, improper drainage, problems due to the soil condition, and
adverse climatic conditions. In certain areas where expansive soil is present, especially in
floodplain areas, significantly threatens lightly loaded structures due to uplift pressures. The
objectives of this study were to identify the factors for the damages in low-rise masonry
buildings, the level of effect of those factors for the damages, and develop a matrix to assess
the damages in low-rise masonry buildings as a case study based approach. This study was
based on the damaged houses which are in Higurakgoda in the North Central province of Sri
Lanka and constructed with commonly available materials. Field investigation, detailed review
of the reports that had been prepared after the investigation done by the National Building
Research Organisation in Sri Lanka, preparation of the database, and analysis of data using
Microsoft Excel and Power BI is the procedure followed in this research. All those houses have
been constructed in an area that is underlain by the Minneri Oya alluvial deposit layer Through
the detailed analysis, poor construction quality and the expansiveness of the soil were identified
as the major factors for damage in the houses in the case study. With the aid of literature, this
study considered liquid limit, plasticity index, clay content, natural water content, and free
swell index of soil as dominant parameters that describe the expansiveness of soil, as well as
the quality of construction, foundation type, wall material, and floor material as the factors
affecting risk due to the poor construction quality as satisfaction. After determining the level
effect of each considered parameter using the Analytical Hierarchy Process and actual data
from the houses in the case study, a matrix that enables the prediction of the risk level of lowrise
masonry houses on expansive soil was developed by combining two matrices developed
to predict soil expansiveness and the risk level due to poor construction quality. The study also
categorises possible damages, proposing an equation to predict the probability of structural
cracks occurring in the building and a rationale to predict critical and possible types of cracks
based on the risk level of the low-rise masonry house that is predicted using the proposed
matrix. Validation of the proposed matrix using actual data demonstrated their accuracy in
predicting risk levels. Therefore, when the construction details of the house and soil properties
are identified, the outcomes of this research can be used to predict the risk level of low-rise
masonry houses, the tendency to get structural cracks, and possible types of cracks. So, these
findings can help assess and mitigate potential damage to low-rise buildings in expansive soil
areas, enabling better construction practices and risk management strategies.