Disaster Resilience Assessment of Building and Transportation System

The paper presents a new methodology to assist decision-makers in the management of critical events such as earthquakes evaluating the recovery time, and the resilience index of a building system that is a component of the physical infrastructure dimension of the PEOPLES Resilience framework. The interdependencies between building system and transportation network in term of accessibility are modeled. Finally, the methodology has been implemented in a software and has been applied in two case studies: (a) the old medieval center of L’Aquila town and (b) the Treasure Island in the San Francisco Bay area

On the modelling of infilled RC frames through strut models

Infill panels largely affect the seismic response of framed constructions. The wide variety in their mechanical and geometrical features has produced many different models and assumptions in their analytical representation. In this paper the simplest and most diffuse analytical approach, based on the introduction of equivalent struts, has been checked. An overview is presented, focusing on the strut dimensions, strength and number. Two case-studies, taken by two different experimental campaigns, have been considered and reproduced. The obtained results have been compared to the experimental ones, and some parameters have been checked for selecting the model to use for analysis

Pushover Analysis for Plan Irregular Building Structures

Nonlinear static procedures (NSPs), also known as "pushover methods", represent the most used tool in the professional practice for assessment of seismic performance of building structures. Most of the methods subscribed by major seismic codes for seismic analysis of new or existing buildings have been originally defined for simple regular structures

Fiscal Policy Under Imperfect Competition: A Survey

This paper surveys the link between imperfect competition and the effects of fiscal policy on output, employment and welfare. We examine static and dynamic models, with and without entry under a variety of assumptions using a common analytical framework. We find that in general there is a robust relationship between the fiscal multiplier and welfare, the tantalizing possibility of Pareto improving fiscal policy is much more elusive. In general, the mechanisms are supply side, and so welfare improving policy, whilst possible, is not a general result

Seismic resilience of a hospital system

This paper presents a comprehensive model to quantify disaster resilience of systems that is defined as the capability to sustain functionality and recover from losses generated by extreme events. The model combines loss estimation and recovery models and can be applied to critical facilities (e.g. hospitals, military buildings, etc.), as well as utility lifelines (e.g. electric power systems, transportation networks, water systems etc.) that are crucial to the response of recovery processes, decisions and policies. Current research trend leads toward the definition of complex recovery models that are able to describe the process over time and the spatial definition of recovery (e.g. meta-models for the case of health care facilities). The model has been applied to a network of hospitals in Memphis, Tennessee. The resilience framework can be used as a decision support tool to increase the resilience index of systems, such as health care facilities, and reduce disaster vulnerability and consequences

A M Reinhorn. Compensation of actuator delay and dynamics for real-time hybrid structural simulation. Earthquake Engineering and Structural Dynamics

Abstract Compensation of delay and dynamic response of servo-hydraulic actuator is critical to the stability and accuracy of hybrid experimental and numerical simulations of the seismic response of structures. In this study, current procedures for compensation of actuator delay are examined and improved procedures are proposed. The proposed procedures need little or no a priori information about the behavior of the test specimen. In addition, a simple approach is introduced for online estimation of system delay and actuator command gain, thus eliminating the need for system calibration before a simulation. The effectiveness of these compensation procedures is verified analytically, numerically and experimentally. Energy error measures resulting from actuator tracking errors are compared to the overall energy input from the excitation. The reduction in added artificial energy due to experimental errors is used to demonstrate the improved accuracy in the simulation obtained from using the proposed procedures. An extrapolation procedure, alternative to the widely-used polynomial extrapolation in fast hybrid testing is proposed based on the same numerical integration procedures used to solve the equation of motion. This procedure is shown to result in smaller amplitude and phase errors

Efficient Modeling Scheme For Transient Analysis Of Inelastic Rc Structures

Simple modeling schemes for efficient and reliable analysis of reinforced concrete structures in the inelastic range are presented. A reinforced concrete structure is discretized into a series of macroelements: beam columns, shear walls, and general-purpose inelastic springs. Each element macromodel is developed from distributed flexibility concepts in which the effects of spread plasticity are implicitly included. Nonlinear material behavior is specified by means of hysteretic force-deformation models that incorporate stiffness degradation, strength deterioration, and pinching or bond-slip effects. The models are incorporated into a microcomputer program that is capable of analyzing two-dimensional or entire three-dimensional wall-frame systems that can be discretized into a series of interconnected parallel frames. Solution modules for nonlinear static, monotonic, quasistatic cyclic, and transient seismic loads are developed. The efficiency and reliability of the modeling are demonstrated in terms of its effectiveness in reproducing experimentally observed behavior. -Author

Evaluation of hollow core composite insulators

This paper presents preliminary results and analysis of a cantilever load test on two types hollow-core composite insulators and summarizes the response of the insulators to different types of loading. The tube of the insulator is a cylindrical shell of fibers-glass in a resin-based matrix with aluminum flange end fittings. The integrity of the tube-flange connection is checked for leaks, slip, damage, and bond degradation. Tests indicate that he actual cantilever load causing failure was much higher than the rated SML provided by the manufacturers. While there were occasionally sounds indicating that something was going on in the insulator prior to catastrophic failure, there was no change in the force deflection curve of the test. While there were slight changes in the damping and frequency of the insulators as the loading increased, the changes were small and did not indicate degradation of the insulator. Two failure modes were observed: failure of the lower flange and shear failure at the tube-flange connection. In one case the shear failure was in the bond to the flange and in the other it was in the tube adjacent to the bonding material. In the unbonded tube, there was clear friction damping. In bonded tubes, the presence of friction damping needs further investigation

Multi-Dimensional Fragility of Structures: Formulation and Evaluation

This study investigates the sensitivity of fragility curves when uncertainties in limit states are considered. Using the MCEER west coast demonstration hospital in the San Fernando Valley in Southern California, influence of structural and response parameters, such as stiffness, acceleration and displacement thresholds, input ground motion, and uncertainties due to structural modeling, are investigated. Different structural parameters that drastically affect fragility are considered. A generalized formula for multidimensional threshold limit states is proposed, and various cases are considered to illustrate the formulation. References, illustrations and tables are included