Stabilitätsbewertung eines schornsteins aus mauerwerk durch schwingungsmessungen

Heutzutage können Gebäude auf verschiedene Arten dynamisch beanspru cht werden. Schienenund Straßenverkehr, Abbrucharbeiten, Maschinen, Glocken, Wind und die menschliche Fortbewegung selbst können Strukturen belasten und Menschen belästigen. Nicht nur eine Schwingungsprognose, sondern auch eine Überwachung bei bestimmten Arbeiten ist wichtig, um die Stabilität von Gebäuden zu gewährleisten. Ein Schornstein aus Vollziegeln wurde bei Abbrucharbeiten der umliegenden Hallen mit einer neuen Schwingungsmesstechnik überwacht. Dieser Artikel beschreibt kurz diese neue Technik und ihre Anwendung während des Monitorings. Zur Beu rteilung der Messwerte wurden die Anhaltswerte der deutschen Norm DIN 4150-3 verwendet und die Ereignisse, bei denen diese Referenzwerte überschritten wurden, eingehend untersucht. Eine dynamische Analyse der Struktur, bei der die Eigenfrequenzen und ihre modalen Massen ermittelt wurden, zeigt, dass die frequenzabhängigen Referenzwerte der DIN 4150-3 zum Schutz von Bauwerken einen relativ hohen Sicherheitsfaktor beinhalten. Eine mögliche Überschreitung der Werte führt nicht sofort zu einem Stabilitätsverlust

Children’s Feedback Preferences in Response to an Experimentally Manipulated Peer Evaluation Outcome: The Role of Depressive Symptoms

The present study examined the linkage between pre-adolescent children’s depressive symptoms and their preferences for receiving positive vs. negative feedback subsequent to being faced with an experimentally manipulated peer evaluation outcome in real time. Participants (n = 142) ages 10 to 13, played a computer contest based on the television show Survivor and were randomized to either a peer rejection (i.e., receiving the lowest total ‘likeability’ score from a group of peer-judges), a peer success (i.e., receiving the highest score), or a control peer evaluation condition. Children’s self-reported feedback preferences were then assessed. Results revealed that participants assigned to the negative evaluation outcome, relative to either the success or the control outcome, showed a significantly higher subsequent preference for negatively tuned feedback. Contrary to previous work and predictions derived from self-verification theory, children higher in depressive symptoms were only more likely to prefer negative feedback in response to the negative peer evaluation outcome. These effects for depression were not accounted for by either state mood at baseline or mood change in response to the feedback manipulation

Children’s coping with in vivo peer rejection: An experimental investigation

We examined children's behavioral coping in response to an in vivo peer rejection manipulation. Participants (N=186) ranging between 10 and 13 years of age, played a computer game based on the television show Survivor and were randomized to either peer rejection (i.e., being voted out of the game) or non-rejection control. During a five-min. post-feedback waiting period children's use of several behavioral coping strategies was assessed. Rejection elicited a marked shift toward more negative affect, but higher levels of perceived social competence attenuated the negative mood shift. Children higher in depressive symptoms were more likely to engage in passive and avoidant coping behavior. Types of coping were largely unaffected by gender and perceived social competence. Implications are discussed. © 2006 Springer Science+Business Media, LLC

Structural Stability Assessment of a Masonry Chimney Subjected to Shocks by Vibration Measurements

Nowadays buildings can be stressed and shocked in different ways. Rail and road traffic, demolition work, machines, bells, wind and human movement itself can burden structures and disturb people. Not only a vibration prognosis, but also a monitoring during certain work is important to ensure buildings’ stability. A masonry chimney subject to shocks due to demolition works of surrounding halls was examined by using a new vibration measuring technique. This paper describes this new technique and its application during monitoring. For the measurement technique, the limit values of the German standard DIN 4150-3 were used and the events where this reference values exceeded, were examined in detail. A dynamic analysis of the structure, where the natural frequencies and their modal masses were determined, shows that the frequency-dependent reference values of the German standard DIN4150-3 for the protection of structures, include a relatively high safety factor. A possible exceeding of the values does not immediately lead to a loss of stability

Group Cognitive-Behavioral Treatment for the Nonpurging Bulimic: An Initial Evaluation

This study tested the initial effects of cognitive-behavioral therapy for binge eating in Ss who do not purge. Forty-four female binge eaters were randomized to either cognitive-behavioral treatment (CB) or a waiting-list (WL) control. Treatment was administered in small groups that met for 10 weekly sessions. At posttreatment a significant difference was found, with 79% of CB Ss reporting abstinence from binge eating and a 94% decrease in binge eating compared with a nonsignificant reduction (9%) in binge eating and zero abstinence rate in WL Ss. Following the posttest assessment, WL Ss were treated and evidenced an 85% reduction in binge episodes and a 73% abstinence rate. Binge eating significantly increased at 10-week follow-up for initially treated Ss; however, the frequency remained significantly improved compared with baseline levels