Richard A. Behr

Retirees on Facebook: can online social networking enhance their health and wellness?

An individuals social network has a strong impact on his or her mental and physical health. This is of particular consequence for senior citizens who are at greater risk of social isolation after retirement, due to loss of spouse, mobility issues, and recent emphasis on aging in place, i.e., in smart homes. Can online social networking sites (SNSs) such as Facebook help alleviate social isolation of aging alone by enabling seniors to maintain high-quality social interactions? How can we make senior-friendly design improvements to SNSs? A preliminary national survey (N =168) of adults over 55 revealed that for those who had joined an SNS, the primary motivation cited for signing up was persuasion by a friend or family member, while non-users cited a strong lack of interest rather than a lack of knowledge or skill, with implications for theory and design of SNS technology for senior citizens.

Light Therapy for Seniors in Long Term Care

OBJECTIVES To investigate the effects of light therapy on cognition, depression, sleep, and circadian rhythms in a general, nonselected population of seniors living in a long term care facility. DESIGN A double-blind, placebo-controlled trial. SETTING The experiment took place at a long term care facility in Pennsylvania. PARTICIPANTS Study participants (15 treatment, 13 placebo) were residents receiving either personal care or skilled nursing care. INTERVENTION Treatment consisted of approximately 400 lux of blue light administered for 30 minutes per day, Monday through Friday, for 4 weeks. The placebo was approximately 75 lux of red light generated from the same device. MEASUREMENTS Behavioral assessments were made using the MicroCog Assessment of Cognitive Functioning, Geriatric Depression Scale, and Profile of Mood States. Daytime sleepiness was evaluated using the Epworth Sleepiness Scale. RESULTS Three of the 4 composite scores from the MicroCog as well as the mean Tension/Anxiety score from the Profile of Mood States showed a significant treatment versus placebo effect. CONCLUSION Blue light treatment led to significant cognitive improvements compared with placebo red light and may be a promising environmental intervention to reduce cognitive symptoms in elderly, long-term care residents.

Damage probability in laminated glass subjected to low velocity small missile impacts

The probability of damage at the impact site in the outer glass ply of laminated glass units subjected to low velocity small missile impacts is investigated. A dynamic, non-linear finite element analysis is applied to compute the stress response on impacts. Based on the cumulative damage theory, a damage factor is introduced and related to Weibulls distribution of probability to characterize the probability of damage. In conjunction with the finite element analysis, controlled experiments are conducted to determine the material constants appearing in the damage model and Weibulls distribution of probability. A parametric study involving impact velocity, glass ply thickness and interlayer thickness is presented.

Architectural Glass Panels with Rounded Corners to Mitigate Earthquake Damage

The concept of employing architectural glass panels with modified corner geometries and edge finish conditions to improve their resistance to earthquake damage has been developed recently. To accomplish this, material is removed at glass panel corners (e.g., by rounding the glass corners) and glass edges are finished in the modified corner regions to minimize protrusions and edge surface roughness. The concept is applicable to a wide variety of architectural glass types and glazing frame types. Full-scale dynamic racking tests have shown that corner radius and glass edge finish conditions near the reshaped corner regions have significant influences on glass cracking and glass fallout drift resistances of monolithic architectural glass panels used in curtain walls.

Seismic Performance of Two-Side Structural Silicone Glazing Systems

This paper presents the results of the first phase of an experimental research program on simulated seismic performance of structural silicone glazed (SSG) curtain wall systems. Full-scale, two-side SSG mockups made up of three side-by-side glass panels were tested under cyclic racking displacements to determine serviceability and ultimate behavior responses. Variables were glass type (annealed and fully tempered) and panel configuration (monolithic, laminated, and insulating glass). In the experiments carried out, damage states such as gasket deformation/pullout, sealant failure (e.g., adhesion/cohesion, etc.), glass cracking glass and fallout were identified and their corresponding drift levels were determined. The extent of damage to silicone sealant was determined through air leakage tests.

Dynamic Racking Performance of an Earthquake‐Isolated Curtain Wall System

Dynamic racking tests, coupled with air leakage tests, were performed on fullsize specimens of a new, Earthquake-Isolated Curtain Wall System and a widely used, conventional curtain wall system (used as an experimental control). Dynamic racking tests simulated seismic movements that could be imposed upon a curtain wall system as a result of interstory drifts. Air leakage tests were performed as an indicator of serviceability performance of both curtain wall systems during the dynamic racking tests. The Earthquake-Isolated Curtain Wall System demonstrated strongly superior performance in terms of both serviceability (glass cracking and air leakage) and life safety (glass fallout). The conventional system exhibited vulnerability to annealed monolithic glass cracking and glass fallout at dynamic racking drift indices of 1.9% and 3.1%, respectively. No glass damage was observed in the earthquake-isolated system up to the dynamic racking displacement limit of the test facility, which corresponded to a drift index of 4.9%. Air leakage rates through vision panels in the conventional system remained constant up to a drift index of 1.9%, after which the air leakage rates increased rapidly. In contrast, air leakage rates through vision panels in the earthquake-isolated system remained unchanged up to the 4.9% drift index capacity of the test facility.

Dynamic strains in architectural laminated glass subjected to low velocity impacts from small projectiles

An experimental validation of a mechanics-based finite element model for architectural laminated glass units subjected to low velocity, two gram projectile impacts is described. The impact situation models a scenario commonly observed during severe windstorms, in which small, hard projectiles, such as roof gravel, impact windows. Controlled experiments were conducted using a calibrated air gun to propel a steel ball against simply supported rectangular laminated glass specimens. Dynamic strains on the inner glass ply were measured using foil strain gages and a high speed data acquisition system. Impact speed, interlayer thickness, glass ply thickness, and glass heat treatment conditions were varied. Dynamic strains predicted by the finite element model were in close agreement with those measured in the laboratory.

Seismic Performance of Stick-Built Four-Side Structural Sealant Glazing Systems and Comparison With Two-Side Structural Sealant Glazing and Dry-Glazed Systems

A research project was undertaken to study the simulated seismic performance of mock-ups of a full-scale, four-side structural sealant glazing (SSG) system. “Stick-built” mock-ups were subjected to cyclic racking displacements in accordance with the American Architectural Manufacturers Association (AAMA) 501.6 test method. Although the test method focuses on glass fallout, drifts associated with serviceability damage states, such as sealant adhesive or cohesive failure, and glass cracking were also identified during the conduct of the tests. Damage to sealant joints was tracked as a function of drift level using visual and video inspections of weather-seals and structural-seals and air-leakage tests. Data from this study are compared with data collected from similar studies on comparable two-side SSG and dry-glazed mock-ups. Contact with panels diagonally above and below a given glass panel at panel corners was found to be the likely cause of initial sealant damage, glass cracking, and glass fallout as opposed to glass-to-frame interactions for two-side SSG and dry-glazed curtain-wall constructions. Thus, modified corner geometries and/or joint dimensions can be used to delay (i.e., shift limit states to higher drift levels) or avoid these damaging panel interactions. Mock-up specimens were also instrumented extensively so that real-time glass-panel translation and rotation, and weather-seal deformation measurements could be recorded. A summary of these measurements is presented and discussed in the context of their follow-up use for informing the development of damage prediction models for SSG curtain walls during seismic loadings. The study shows that stick-built curtain walls with four-side SSG configuration are expected to have higher drift capacity compared to two-side SSG and both are expected to have higher drift capacity compared to dry-glazed configurations.

Fragility Curves for Architectural Glass in Stick-Built Glazing Systems

Fragility functions are presented for 15 glazing system configurations in support of Applied Technology Council efforts to develop a performance-based seismic design approach for building performance assessment. The study includes seismic evaluation of curtain wall and storefront systems in terms of probability and the consequences of damage, including economic and life safety consequences. Defined damage states consist of gasket degradation, initial glass cracking and crushing, and glass fallout. Alternatives are offered to the provided prototype fragilities for configurations with differing glazing characteristics, which account for varying glass-to-frame clearance, aspect ratio, and glass panel dimensions. Issues related to applying laboratory-based fragility data to actual glazing systems in the field are addressed.

Development of Finite-Element Modeling Approach for Lateral Load Analysis of Dry-Glazed Curtain Walls

This paper presents a finite-element modeling option to provide an analytical approach for a seismic analysis of dry-glazed curtain-wall systems. In this modeling approach, Ansys finite-element software was used to model the glass panel, aluminum glazing frame, perimeter rubber gaskets, rubber setting and side blocks, glass-to-frame clearances, and glass-to-frame contact once the clearance was overcome by in-plane drift. The results of the finite-element modeling of the curtain-wall system were compared with full-scale laboratory test results. The effect of some of the parameters such as gasket friction and aspect ratio were evaluated. The study showed that finite-element modeling is a viable approach for analytical evaluation of curtain walls. The modeling can function to predict the drift associated with glass-panel cracking. Further refinement of the modeling approach developed can increase the accuracy of the prediction.