ABSTRACT
The adition of viscoelastic braces in structures for vibration reduction was proposed and implemented in the past decade in metal models or full-scale structures. Viscoelastic braces provide energy dissipation, while the structures remains by-and-large elastic. In reinforced concrete structures, the seismic response in by-and-large inelastic, which is often accompanied by permanent deformations and damage. The addition of viscoelastic dampers can dissipate energy at the early stages of cracking of the concrete elemnts and reduce the development of damage. With proper selectio of dampers, this damage can be substantially reduced or even eliminated. However the addition of viscoelastic dampers may stiffen the structure unnecessarily producing increased inertial forces and base shears when subjected to seismic motion. The quantification of the influence of viscous and elastic stiffness properties of dampers during the inelastic response of reinforced concrete structures is the subject of this invetigation. Models for analysis of inelastic response with damege indexing for reinforced concrete structures that include viscoelastic braces are developed and calibrated using experimental data produced by shaking table tests. These models are then used to determine the variation of expected damage in the presence of damping and quantify the hysteretic energy dissipation along with the damping energy (AU)
Subject(s)
Engineering , Construction Materials , Risk Assessment , Facility Regulation and ControlABSTRACT
The performance of Gravity Load Designed (GLD) building has been studied at severalinstitutions over the past five years, It has been fount that under earthquake loads, extensive damage occur in the frame joints and the flexibility of these structures are of primary concern. However, relatively inexpensive retrofit techniques for such structures might suffice for regions of low the moderate seismicity, Several local and integrated global techniques are suggested and studied (AU)
Subject(s)
Earthquakes , Construction Industry , 34661 , Engineering , Risk AssessmentABSTRACT
A series of varying intensity simulated ground motion tests were perfomed on the one-third scale building model using scaled accelerograms on the shaking table to represent minor, moderate, and severe earthquakes. The dynamic characteristics of the model ofter each seismic event were identified from white noise shaling table tests. The results of this expiremental investigation are presented in this report.(AU)
Subject(s)
Engineering , Methods , Models, Structural , Earthquakes , 34661ABSTRACT
This report is Part II of a two part series on the evaluation of seismic retrofit methods for concrete frame structures. It deals with the behavior of the entire structural system when several retrofit techniques are applied to individual components. An analytical and an experimental study was done on a scaled model of a structure and several retrofit techniques were evaluiated. Pat I describes the evaluation of individual components retrofitted and tested with cyclic loading, that provided the base for modeling of the entire structure presented in this report.(AU)
Subject(s)
Engineering , 34661 , Methods , EarthquakesABSTRACT
This report is part I of a three-part series prepared fpor a comprehensive Evaluation of typical gravity load designed low-rise reinforced concrete frame buildings (lightly reinforced concrete structures) for seismic adequacy. The study was done at State University of New York at Buffalo -Earthquake Simulation Laboratory on a 1:3 scale building model designed for gravity loads only. No considerations were made for seismic resistance and the general non-seismic detailing provisions of ACI-318-89 were used for the design. The one-third scale three story model, one-bay by three-bay, of a typical office building was constructed to represent the critical interior bay of a prototype structure.(AU)
