The study objective was to evaluate the psychometric properties of a decisional conflict scale (DCS) that elicits: 1) health-care consumers' uncertainty in making a health-related decision; 2) the factors contributing to the uncertainty; and 3) health-care consumers' perceived effective decision making. The DCS was developed in response to the lack of instruments available to evaluate health-care-consumer decision aids and to tailor decision-supporting interventions to particular consumer needs. The scale was evaluated with 909 individuals deciding about influenza immunization or breast cancer screening. A subsample of respondents was retested two weeks later. The test-retest reliability coefficient was 0.81. Internal consistency coefficients ranged from 0.78 to 0.92. The DCS discriminated significantly (p < 0.0002) between those who had strong intentions either to accept or to decline invitations to receive influenza vaccine or breast cancer screening and those whose intentions were uncertain. The scale also discriminated significantly (p < 0.0002) between those who accepted or rejected immunization and those who delayed their decisions to be immunized. There was a weak inverse correlation (r = -0.16, p < 0.05) between the DCS and knowledge test scores. The psychometric properties of the scale are acceptable. It is feasible and easy to administer. Evaluations of responsiveness to change and validation with more difficult decisions are warranted.

Validation of a Decisional Conflict Scale

This tutorial/survey paper: (1) provides a concise point of departure for researchers and practitioners alike wishing to assess the current state of the art in the control and monitoring of civil engineering structures; and (2) provides a link between structural control and other fields of control theory, pointing out both differences and similarities, and points out where future research and application efforts are likely to prove fruitful. The paper consists of the following sections: section 1 is an introduction; section 2 deals with passive energy dissipation; section 3 deals with active control; section 4 deals with hybrid and semiactive control systems; section 5 discusses sensors for structural control; section 6 deals with smart material systems; section 7 deals with health monitoring and damage detection; and section 8 deals with research needs. An extensive list of references is provided in the references section.

Structural control: past, present, and future

................................................................................................................................. iii ACKNOWLEDGMENTS ........................................................................................................... iv CONTENTS....................................................................................................................................v LIST OF FIGURES ..................................................................................................................... xi LIST OF TABLES .....................................................................................................................xxv

Global collapse of frame structures under seismic excitations

A decision aid for women considering hormone therapy after menopause: decision support framework and evaluation

This paper presents a summary of current practice and recent developments in the application of passive energy dissipation systems for seismic protection of structures. The emphasis is on the application of passive energy dissipation systems within the framing of building structures. Major topics that are presented include basic principles of energy dissipation systems, descriptions of the mechanical behavior and mathematical modeling of selected passive energy dissipation devices, advantages and disadvantages of these devices, development of guidelines and design philosophy for analysis and design of structures employing energy dissipation devices, and design considerations that are unique to structures with energy dissipation devices. A selection of recent applications of passive energy dissipation systems is also presented.

Energy dissipation systems for seismic applications: Current practice and recent developments

A major concern in seismic performance testing is whether the loading conditions imposed on a test specimen are representative of those that might occur during an actual earthquake. An on-line computer-controlled experimental procedure has been recently developed that appears to combine the simplicity of quasistatic testing with the realism of shaking table tests. The basis of this so called pseudodynamic test method is summarized in this paper. Recent research results are examined to identify the method’s capabilities and limitations. Efforts to extend the applicability of the method are highlighted.

Pseudodynamic Test Method—Current Status and Future Directions

Supplemental damping devices have been used to decrease the dynamic response of buildings subjected to wind and earthquake inputs. These devices can be generalized into the following three major types: friction devices, viscous or viscoelastic devices, and material yield devices. Lead dampers would be included in this last case, even though its characteristics do not involve yielding. A study of one of the metallic yield devices, the steel‐plate added damping and stiffness (ADAS) device, is presented. Yield force, yield displacement, strain‐hardening ratio, ratio of the device stiffness to the bracing member stiffness, and ratio of device stiffness to structural story stiffness without the device in place have been identified as the most important parameters to characterize the performance of this device. The influence of these parameters on earthquake response of building structures is analyzed. The results show that these devices can substantially increase the energy dissipation capacity of a structure ...

Influence of ADAS Element Parameters on Building Seismic Response

Seventeen tube specimens and eight angle specimens were tested under repeated axial loading. Length of the specimens varied from 20 in. to 59 in. and their effective slenderness ratio varied from 30 to 140. The objective of this experimental investigation was to quantify the reduction in maximum compressive loads and increase in member length, to study the influence of mode of buckling and shape of cross section on the hysteresis behavior and energy dissipation through hysteretic cycles. It was concluded that local buckling and shape of the cross section can have significant influence on the hysteresis behavior of axially loaded steel members. A hysteresis model is proposed for tubular members which is in reasonable agreement with the observed inelastic behavior.

Hysteretic Cycles of Axially Loaded Steel Members

The behavior of double‐angle bracing members subjected to out‐of plane buckling due to severe cyclic load reversals is investigated. Nine full‐size test specimens were subjected to severe inelastic axial deformations. Test specimens were subjected to severe inelastic axial deformations. Test specimens were made of back‐to‐back A36 steel angle sections connected to the end gusset plates by fillet welds or high‐strength bolts. Five of the test specimens were designed according to current design procedures and code requirements. These specimens experienced fracture in gusset plates and stitches during early cycles of loading. Based on the observations and analysis of the behavior of these specimens, new design procedures are proposed for improved ductility and energy dissipation capacity of double‐angle bracing members which buckle out of plane of gusset plates. Tests of four specimens, designed using proposed procedures, showed significant improvement in their performances.

Cyclic Out-of-Plane Buckling of Double-Angle Bracing

The vibration of floor systems caused by human movements can be reduced using tuned mass dampers. The component mode synthesis (CMS) method is used to compute the response of the floor‐tuned mass damper system using only a few natural modes of the floor. Models representing typical two‐dimensional floor‐system behavior are used to illustrate this technique. Tuning parameters obtained using the CMS method and an equivalent single degree of freedom (SDOF) model to represent the vibration characteristics of a multiple degree of freedom system are compared. It is found that using the CMS method can result in the optimum parameters of the tuned mass dampers regardless of the closeness of the natural frequencies of the system. This is not the case when the equivalent SDOF model is used. Therefore, it is concluded that use of CMS method to represent the model for optimization produces tuned mass damper parameters that provide global reduction in the amplitude of vibration for cases with and without closely space...

Robert D. Hanson

Papers

Pseudodynamic Test Method—Current Status and Future Directions

Influence of ADAS Element Parameters on Building Seismic Response

Hysteretic Cycles of Axially Loaded Steel Members

Cyclic Out-of-Plane Buckling of Double-Angle Bracing

Tuned Mass Dampers to Control Floor Vibration from Humans