The significance of seismic hazard on structural design in Zambia
Date
2020
Authors
Mileji, Innocent. C.
Journal Title
Journal ISSN
Volume Title
Publisher
The University of Zambia
Abstract
Design and construction practices in Zambia have tended to neglect the risk posed by seismicity
on structures, and no earthquake design and construction guides exist. The recent earthquake
occurrences suggest that earthquake incidences can no longer be ignored.
The research studied the occurrence and significance of earthquakes on the design of structures
in Zambia. It advanced the hypothesis that there was sufficient evidence to warrant factoring in
the risk posed by seismicity in design and construction practices, and hence the need to develop
an earthquake design and construction guide. While Zambia’s location in the interior of the
African plate may apparently suggest low seismic risk, the influence of the East Africa rift
valley cannot be underestimated. Even with limited history and records of earthquake activity
in Zambia and the sub region, there are sufficient records of major earthquakes resulting in
damage to structures and even loss of lives.
The research methodology included literature review of works related to seismicity in Zambia
and the sub-region, analysis of raw earthquake data obtained from earthquake monitoring
agencies, review of available seismic reports on Zambia and a questionnaire survey targeted at
practicing structural engineers and related professionals. Recorded earthquake events and their
physical effects on structures, as well as the prevalent structural design practises amongst
engineers in Zambia, were reviewed.
The research revealed evidence of physical damage resulting from earthquakes. Seismic hazard
analysis predicted significant values of peak ground acceleration (PGA) of up to 0.5 g and 0.7
g for return periods of 475 years and 950 years, respectively. The highest values of PGA were
observed in Zone 5 of the study which is around Lake Tanganyika in the northern region of
Zambia while the lowest values were observed around western region of Zambia. The research
noted that most earthquakes in the catalogue were within a depth of 10km which highlights the
potential hazard posed by significantly large earthquakes in the region. The limited seismic
consideration prevalent in design practises in Zambia is largely attributed to the lack of an
earthquake design guide and the preconceived notion that Zambia and the sub-region have
insignificant earthquake activity.
It is recommended that the Engineering Institution of Zambia (EIZ) should spearhead
development of a seismic design and construction guide for Zambia.
Keywords: Earthquake, Seismicity, Structural Design and Construction
Description
Thesis
Keywords
Seismology--Zambia. , Earthquake resistant design. , Structural design. , Bridges--Design and construction. , Tall buildings--Design and construction.