Authors :
Rahul Leslie
Volume/Issue :
Volume 7 - 2022, Issue 5 - May
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/3BbnueI
DOI :
https://doi.org/10.5281/zenodo.6888843
Abstract :
The loss of sign in the output results of
Response Spectrum Method has been a subject of
discussion in literature, highlighting the issues caused,
manifesting primarily in: (i) the loss of relative signs of
forces acting on the structural members and (ii) the loss
of relative signs of the support reactions. The method of
Dominant Mode Signage (DMS) had been presented as a
remedy in some of the structural analysis packages to
tackle the issue. The intention of this paper is to elaborate
an alternate manual method of applying signs to the
support reactions for those using structural analysis
packages not yet equipped with the DMS facility,
presenting an easy step-by-step process fit for utilising on
a day-to-day basis.
It also demonstrates why a plot of the envelope of
maximum footing pressures on soil on the footing is not
symmetric in case of the Response Spectrum Method
approach, even for a symmetric building with symmetric
loading and supported on a symmetric combined footing,
while it is rendered symmetric for the Seismic Coefficient
Method approach (ie., the Static method), and as
demonstrated, for the proposed method too.
Keywords :
Response Spectrum Method, support reactions, loss of sign.
The loss of sign in the output results of
Response Spectrum Method has been a subject of
discussion in literature, highlighting the issues caused,
manifesting primarily in: (i) the loss of relative signs of
forces acting on the structural members and (ii) the loss
of relative signs of the support reactions. The method of
Dominant Mode Signage (DMS) had been presented as a
remedy in some of the structural analysis packages to
tackle the issue. The intention of this paper is to elaborate
an alternate manual method of applying signs to the
support reactions for those using structural analysis
packages not yet equipped with the DMS facility,
presenting an easy step-by-step process fit for utilising on
a day-to-day basis.
It also demonstrates why a plot of the envelope of
maximum footing pressures on soil on the footing is not
symmetric in case of the Response Spectrum Method
approach, even for a symmetric building with symmetric
loading and supported on a symmetric combined footing,
while it is rendered symmetric for the Seismic Coefficient
Method approach (ie., the Static method), and as
demonstrated, for the proposed method too.
Keywords :
Response Spectrum Method, support reactions, loss of sign.
