EVALUATION OF LATERAL LOAD DISTRIBUTION IN NONLINEAR STATIC PROCEDURES FOR RCC BUILDING
SRIKANTH DEVI1, K.RAMA MOHANA RAO 2, REFAAT TALEB ISMAIL3
1 Postgraduate Student, Department of civil engineering, JNTU Hyderabad.firstname.lastname@example.org 2 Professor, Civil engineering and Director BICS JNTU Hyderabad. 3 Research scholar, JNTU Hyderabad. email@example.com
ABSTRACT:Nonlinear static analysis using pushover procedures are becoming increasingly common in engineering practice for seismic evaluation of building structures. Various invariant distributions of lateral forces are recommended in FEMA-356 (2000) to perform a pushover analysis. However, the use of these invariant force distributions does not adequately represent the effects…show more content… INTRODUCTION
Although current seismic design practice is still governed by force-based design principles, a common trend in structural earthquake engineering practice is to use performance-based seismic evaluation methods for the estimation of inelastic deformation demands in structural members. A widely used and popular approach to establish these demands is a “pushover” analysis in which a model of the building structure is subjected to an inverted triangular distribution of lateral forces.
2. NON-LINEAR STATIC ANALYSIS
As the name suggests this procedure is essentially a static analysis, in which the static loads are applied in an incremental fashion until the ultimate state of the structure is attained. The non-linear designation comes from the fact that the various components/elements are modeled using a non-linear mathematical model.
This section is dedicated to describe the main steps of this procedure, in a general manner. This is followed mainly because the concept of the non-linear static procedure is still relatively new and is the topic for discussion in this study.
The employment of the non-linear staticprocedure involves four distinct phases as described below and illustrated in…show more content… Calculate the lateral force at i-th storey for n-th mode from Equation (4.4).
Where Pn: modal participation factor for the n-th mode
Øin: amplitude of n-th mode at i-th storey An: pseudo-acceleration of the n-th modeSDOF elastic system
2. Calculate the storey shears, Where N is the total number of stories
3. Combine the modal storey shears using SRSS rule.
4. Back calculate the lateral storey forces, Fi, at storey levels from the combined storey shears, Vi starting from the top