Martijn Schildkamp
Martijn Schildkamp

Martijn Schildkamp
Ph.D.; director, non-profit organization «Smart Shelter Foundation» (SSF);

Scopus: 57207859724


Publications

Base shear seismic demand comparison for buildings with natural stone walls in Nepal, Russia and Tajikistan
Issue: #6-2022
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Introduction: The current norms for construction in seismic areas in the Russian Federation prohibit the construction of buildings with natural stone walls, but for the restoration and reconstruction of historic buildings located in earthquake-prone regions, seismic demand of such structures should be determined. Full base shear seismic demand analyses with calculated examples for heavy stone masonry buildings are not present in the literature.

Materials and methods: To address this shortcoming, analyses and calculations are performed on nominally reinforced natural stone walls house and school designs, as typically built in Nepal. A detailed comparison of the seismic codes of the three countries Nepal, Russian and Tajikistan was carried out.

Results: This paper compares the base shear formulas and the inertia forces distributions of these codes, as well as material densities, seismic weights, seismic zoning, natural periods of vibration, response spectra, importance factors and seismic load combinations. Large differences between approaches and coefficients are observed. Then, by following Equivalent Lateral Force method (ELF) and simplified modal analysis (S-modal) the base shear and story shears are calculated for a design peak ground acceleration of 0.20 g, as well as the effects of critical load combinations on the forces and moments acting on the lateral-resisting elements. Particular attention is paid to possible discrepancies and interpretations of certain provisions of the normative documents of the Russian Federation and Tajikistan. This study also proposes a new terminology to emphasize the differences between two countries: the methods of double (DCA) and of single application (SCA) of the combination coefficients.

Conclusions: Overall, it is observed that heavy-masonry–light-floor systems with negligible diaphragm action behave different under seismic motion than most other building typologies. Given the observations in this paper, the applicability of conventional ELF and S-Modal methods for heavy masonry buildings is questionable. The codes however do not introduce modified approaches that address these differences. The paper ends with an appeal for global collaboration under the research project SMARTnet. Further, the paper aims to start discussions within the Russian community and neighboring countries about possible revisions and improvements of certain inaccuracies and ambiguities in the various norms.