Update to ASCE/SEI 41 Concrete Provisions

Abstract

A proposed supplement to ASCE/SEI 41 Seismic Rehabilitation of Existing Buildings has been developed for the purpose of updating provisions related to existing reinforced concrete buildings. Based on experimental evidence and empirical models, the proposed supplement includes revisions to modeling parameters and acceptance criteria for reinforced concrete beams, columns, structural walls, beam-column joints, and slab-column frames. The revisions are expected to result in substantially more accurate and, in most cases, more liberal assessments of the structural capacity of concrete components in seismic retrofit projects.

Influence Factors for the Assessment of Maximum Lateral Seismic Deformations in Italian Multistorey Rc Buildings

“…The response of beams and columns is represented by axially rigid elastic elements. Both beams and columns are assumed cracked and the element stiffness is evaluated according to [19]. Rigid beam-columns joints of finite size are adopted in the model.…”

Stiffness Modeling of Rc Columns Reinforced With Plain Rebars

“…The literature study conducted on the effective stiffness reveals that all effective stiffness formulations are for columns longitudinally reinforced with deformed rebars. ASCE/SEI 41 update report [15] states that lower effective stiffness values might be attained for the structural components with plain rebars due to the reduced bond stress levels without further elaboration. Thus, it is expected that the effective stiffness recommended in assessment guidelines may show a tendency to overestimate the effective stiffness of vertical load bearing members having plain reinforcement.…”

An Empirical-Based Approach for Modeling and Assessment of Rc Columns With Plain Bars

“…The US standard ASCE/SEI 41-13 [21] provides a procedure for the failure mode classification and, accordingly, empirical deformation capacity parameters calibrated to satisfy a target failure probability, depending on the failure mode. Such provisions were based on a proposal by Elwood et al [1]. In [22] and [3] a modification to ASCE/SEI 41 provisions was proposed, in particular consisting of empirical expressions -not dependent on the expected failure mode -providing a median estimate of deformation capacity parameters.…”

“…These coefficients, in particular, account for the reduction of the ultimate chord rotation as a function of limited lap splice length. Different authors have evaluated the effectiveness of these coefficients, in some cases proposing improvements or alternative expressions [1][23] [24]. Moreover, the effectiveness of current ASCE/SEI 41 provisions for elements with plain bars has been evaluated in [25], highlighting a significant conservatism.…”

“…[1], [2], [3]). The post-elastic response of members with plain bars can be significantly different compared to members with deformed bars, due to the lower bond capacities [4] [5] that, for instance, lead to higher deformability contribution of the fixed-end-rotation mechanism [6] [7].…”