Proposal and application of the Incremental Modal Pushover Analysis (IMPA)

Abstract

Existing reinforced concrete frame buildings designed for vertical load only could suffer severe damage during earthquakes. In recent years, many research activities have been paid to develop reliable and practical analysis procedure to identify the safety level of existing structures. The Incremental Dynamic Analysis (IDA) is considered to be one of the most accurate methods to estimate seismic demand and capacity of structures. But it requires the execution of many nonlinear response history analyses (NL_RHA) in order to describe the entire range of structural response. The research discussed in this paper deals with proposal of an efficient Incremental Modal Pushover Analysis (IMPA) to obtain capacity curves by replacing the NL_RHA of the IDA procedure by Modal Pushover Analysis (MPA). In this work, the basic idea of IMPA is presented and the step-by-step computational procedure is then summarized. This new procedure, accounting the higher modes effects, does not need the execution of complex NL-RHA, but only simpler nonlinear static analysis. Then, the new procedure is applied to an existing irregular building. The capacity curves obtained by different procedures (standard pushover analysis, IMPA and IDA) are presented and discussed.

Proposal of A Non Linear Static Analysis Procedure for Bridges: The Incremental Modal Pushover Analysis for Bridges (IMPAβ)

“…The originally developed incremental modal pushover analysis (IMPA) is a pushover-based procedure that requires the execution of MPA and an evaluation of structural performance within a range of different seismic actions and intensity. The IMPA procedure is described in a convenient step-by-step form in [3]; therefore in this paper the IMPA procedure is briefly reported and only the specifications for bridges, required to describe the proposed IMPAb, are reported and discussed. Remembering that the IMPA requires the execution of several MPAs, the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by a non-linear static analysis using the inertia force distribution sn for each mode:…”

“…The idea of IMPAb originates from the intent of extending the experience made by the same authors, dealing with seismic behavior of building structures sensitive to higher modes, and which led to the development of a well performing procedure named Incremental Modal Pushover Analysis (IMPA) [3,4].…”

“…As detailed in [3] and summarized in section 2.4, IMPA requires the execution of the Modal Pushover Analysis (MPA) [6] but, in order to validate it and verify the best pushover procedure to be proposed considering the bridge case, developing IMPAb, other pushover methods have been considered too namely: pushover with a load pattern proportional to the first mode (SPA) or uniform (UPA) (this two load pattern are commonly adopted in pushover analysis as suggested in FEMA-356 [7] and Eurocode 8 [8][9]).…”

Experimental Investigation of the Shear Strength of RC Beams Extracted from an Old Structure and Strengthened by Carbon FRP U-Strips

“…The CFRP effective strength (f fed ) that produces debonding of the CFRP reinforcement is 695 MPa by Equation (18) in CNR-DT 200 R1/2013 [66]. This stress is function of the debonding strength (f fdd ) calculated by Equation (23) in CNR-DT 200 R1/2013 [66] that is equal to 715 MPa assuming the tensile strength of the CFRP fabric equal to 2400 MPa, the mean cubic compressive strength of the restored concrete cover equal to 35 MPa and the unit value for the partial safety coefficients in [66]. The experimental CFRP stress at the strips debonding is very similar to the predicted value by the code equations [66].…”

Seismic performance of a high-rise residential building model in Purwokerto, Indonesia

“…Earthquake engineering comprises two critical terms: performance-based design and performance-based evaluation. The performance-based design focuses on structural design [5][6][7][8] while performance-based evaluation focuses on a constructed structural analysis [9][10][11]. …”