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Item type:Publication, Access status: with files , Vergleich numerischer Analyse- und Diskretisierungsverfahren für instabilitätsgefährdete SchalentragwerkeNumerische Stabilitätsanalysen dünner Schalentragwerke sind anspruchsvoll und rechenintensiv. Die Wahl geeigneter Imperfektionen ist nach EC3 nicht eindeutig geregelt und fehleranfällig. Der vorliegende Beitrag diskutiert den Einfluss eigenformaffiner Imperfektionen auf die numerische Traglast von Schalentragwerken. Zudem werden unterschiedliche Analyse- und Diskretisierungsverfahren hinsichtlich Genauigkeit und Effizienz verglichen. Im vorliegenden Beitrag werden Zwischenergebnisse aus umfangreichen, systematischen numerischen Konvergenz- und Parameterstudien vorgestellt und diskutiert.Publicationtype: Conference Paper26 9 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Eccentric-wing flutter stabilizer for bridges – Analysis, tests, design, and costs(2018-10); ; A device is presented that aims at preventing bridge flutter. It consists of wings positioned along the sides of, and fixed to, the bridge deck. Flutter suppression effectiveness is high provided the lateral eccentricity of the wings is large. It is a passive aerodynamic device that is presumably more cost-efficient than other passive measures or devices. Moreover, it does not contain moving parts. This is an advantage over devices with moving parts, which meet resistance due to reliability and durability concerns. Wind-tunnel tests were performed in which the flutter speed of a bridge deck sectional model without wings and with wings mounted in various configurations was measured. The experimental results are presented and compared with the results of flutter analyses using finite aeroelastic beam elements. Using the analytical approach, also the effect of the distribution of the wings along the length of a bridge was studied to optimize this distribution. Preliminary design studies for the wings and their support structures as well as quantity and cost estimates are presented. For a representative example bridge and wing configuration, an increase of 22% of flutter speed is reached at a cost increase of 2.5%.Publicationtype: Journal Article161 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Ein angepasstes Ermüdungslastmodell für stählerne Stabbogenbrücken mit freistehenden BögenLateral arch vibrations are frequently observed at existing steel bowstring bridges. These result from critical axle arrangement loads of crossing trucks and resonance. A long post oscillation is often detected. Hence, a large fatigue load for the arch and the adjacent construction components exists, which is included in the actual standards insufficiently. An extended fatigue load model for structural design is presented to incorporate the large fatigue load while planning such bridges. It is called ELM 3a and is based on the fatigue load model 3 given in DIN Fachbericht 101. An adjustable distance between axles and an adjustable speed are introduced for the ELM 3a to maximize the lateral arch vibrations. A simplified impulse form is given for the wheel loads in this context, which can be used in an FEM calculation for example. © Ernst & Sohn;.Publicationtype: Journal Article67