Loading Protocols for ASCE 41 Backbone Curves

2016 ◽  
Vol 32 (4) ◽  
pp. 2513-2532 ◽  
Author(s):  
Bruce F. Maison ◽  
Matthew S. Speicher
Keyword(s):  
Hysteresis Loops ◽  
Earthquake Response ◽  
Existing Buildings ◽  
Cyclic Tests ◽  
Seismic Evaluation ◽  
Backbone Curve ◽  
Seismic Demands ◽  
Loading Pattern ◽  
Industry Standard ◽  
Reversed Cyclic

ASCE 41 is the industry standard for seismic evaluation and retrofit of existing buildings. It allows for alternative component modeling and acceptance criteria based on a backbone curve constructed from envelopes of component hysteresis loops derived via experimental cyclic tests. ASCE 41-13 requires use of loading protocols having fully reversed cyclic loadings with increasing displacement levels. However, recent research summarized herein indicates the need for inclusion of different protocols that pay specific attention to behavior incipient to collapse. This view is supported by example building computer earthquake response simulations described herein. A generalized loading pattern derived from the simulations found relatively few drift excursions having one-direction bias, suggesting one-sided cyclic and/or monotonic tests may be better for describing building inelastic seismic demands.

scholarly journals Pounding Effects on the Earthquake Response of Adjacent Reinforced Concrete Structures Strengthened by Cable Elements

2014 ◽  
Vol 44 (2) ◽  
pp. 41-56 ◽  
Author(s):  
Angelos Liolios ◽  
Asterios Liolios ◽  
George Hatzigeorgiou ◽  
Stefan Radev
Keyword(s):  
Reinforced Concrete ◽  
Numerical Approach ◽  
Earthquake Response ◽  
Existing Buildings ◽  
The Finite Element Method ◽  
Time Step ◽  
Engineering Structures ◽  
Rc Structures ◽  
Incremental Approach ◽  
Rc Frames

Abstract A numerical approach for estimating the effects of pounding (seismic interaction) on the response of adjacent Civil Engineering structures is presented. Emphasis is given to reinforced concrete (RC) frames of existing buildings which are seismically strengthened by cable-elements. A double discretization, in space by the Finite Element Method and in time by a direct incremental approach is used. The unilateral behaviours of both, the cable-elements and the interfaces contact-constraints, are taken strictly into account and result to inequality constitutive conditions. So, in each time-step, a non-convex linear complementarity problem is solved. It is found that pounding and cable strengthening have significant effects on the earthquake response and, hence, on the seismic upgrading of existing adjacent RC structures.

Reversed Cyclic Tests of 1/13 Scale Cylindrical Concrete Containment Structures

2019 ◽  
pp. 131-149
Author(s):  
Chiun-Lin Wu ◽  
Thomas T. C. Hsu ◽  
Che-Yu Chang ◽  
Hu-Jhong Lu ◽  
Hsuan-Chih Yang ◽  
...  
Keyword(s):  
Cyclic Tests ◽  
Reversed Cyclic

Strain Rate and Loading Waveform Effects on an Energy-Based Fatigue Life Prediction for AL6061-T6

2012 ◽  
Author(s):  
Todd Letcher ◽  
M.-H. Herman Shen ◽  
Onome Scott-Emuakpor ◽  
Tommy George ◽  
Charles Cross
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Hysteresis Loops ◽  
Sine Wave ◽  
Wave Loading ◽  
Cumulative Energy ◽  
Loading Pattern ◽  
Loading Waveform ◽  
Strain Rate Loading

The energy-based lifing method is based on the theory that the cumulative energy in all hysteresis loops of a specimens’ lifetime is equal to the energy in a monotonic tension test. Based on this theory, fatigue life can be calculated by dividing monotonic strain energy by a hysteresis energy model, which is a function of stress amplitude. Recent studies have focused on developing this method for a sine wave loading pattern — a variable strain rate. In order to remove the effects of a variable strain rate throughout the fatigue cycle, a constant strain rate triangle wave loading pattern was tested. The testing was conducted at various frequencies to evaluate the effects of multiple constant strain rates. Hysteresis loops created with sine wave loading and triangle loading were compared. The effects of variable and constant strain rate loading patterns on hysteresis loops throughout a specimens’ fatigue life are examined.

scholarly journals SEISMIC EVALUATION OF EXISTING BUILDINGS ACCORDING TO DOCUMENT FEMA 310

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Marina Latinović
Keyword(s):  
Evaluation Process ◽  
Seismic Resistance ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Existing Buildings ◽  
Seismic Evaluation ◽  
Building Type ◽  
Second Tier

In this paper, the principle of application of the FEMA310 document for seismic evaluation of existing buildings is briefly illustrated, for any building type, and examples of evaluation are given for the first and second tier of evaluation process, for two types of masonry structures. The application of this document at tier one and tier two of the evaluation process is a conservative, simplified way of determining seismic resistance, based on many experiential data and including the most important parameters of buildings that can affect seismic resistance. Instructions given by FEMA310 are easy to apply, but are adapted to US standards. Two examples for evaluation of masonry buildings on first and second tier of evaluation are given, for masonry buildings with rigid and flexible diaphragmas.

scholarly journals Comparative study on acceptance criteria for non-ductile reinforced concrete columns

2018 ◽  
Vol 51 (4) ◽  
pp. 183-196
Author(s):  
Opabola Eyitayo ◽  
Kenneth J. Elwood
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Concrete Columns ◽  
Deformation Capacity ◽  
Existing Buildings ◽  
Acceptance Criteria ◽  
Reinforced Concrete Columns ◽  
Seismic Demands ◽  
Concrete Buildings ◽  
Direct Rotation

Poor seismic performance of older reinforced concrete buildings in past seismic events has frequently been attributed to failure of non-ductile columns not detailed for seismic demands. The Seismic Assessment of Existing Buildings Guidelines developed in New Zealand (NZ Guideline) provides a performance-based engineering framework for assessment of existing buildings, with concrete buildings covered in section C5. This study compares the probable failure mode and deformation capacity assessed based on NZ Guideline, ASCE/SEI 41-13, and ASCE/SEI 41-17 with the results from quasi-static cyclic tests conducted on 52 rectangular and 13 circular reinforced concrete columns with reinforcement details similar to those of non-ductile columns. Results indicate that the general curvature-based method of the NZ Guideline was not able to identify the observed failure mode but generally provides a conservative estimate of deformation capacity in comparison with ASCE/SEI 41-17. Based on the results of this study, a direct rotation-based acceptance criteria is proposed for NZ Guidelines. Also, slight modifications, to reduce conservatism, have been proposed for the curvature-based method.

Sign in / Sign up

Export Citation Format

Share Document