Behavior of externally prestressed segmental towers' dry joint under torsion effects

Abstract

With the rising demand of clean wind energy, concrete and hybrid segmental towers have been frequently constructed in recent years. In the area of very high towers, they have replaced the traditional steel towers due to better transportability and economy. However, the joints between adjacent segments have led to questions, which are not satisfactorily resolved by current models or calculation approaches. The transmission of shear forces and torsion moments take place exclusively inside the so-called horizontal dry joint. Current calculations are carried out according to the torsion theories of Bredt for ring cross sections and Saint-Venant for open thin-walled cross sections. However, these approaches, which are used to describe the bearing and deformation behavior of such joints, are insufficient. Depending on the loading situation, this leads to both unsafe results and unused strength. In this paper, an actual wind tower construction with a ring cross section is thoroughly analyzed based on current theory. Additionally, numerical simulations are carried out. The torsion resistance of segmental tower structures is investigated in detail. The inaccuracy of current theories is demonstrated.

Modellentwicklung torsionsbeanspruchter Kreisringsegmente mit trockenen Fugen

“…In weiteren Untersuchungen gilt es, das Modell durch die Komponente der Querkraft zu ergänzen, da es im Allgemeinen bei stabförmigen Bauteilen zu einer gleichzeitigen Einwirkung aus Biege‐ und Querkraftbeanspruchungen kommt. Wobei in [8] von Kang et al dargestellt wurde, dass die Komponente der Querkraft aufgrund der geringen Lastgrößen bei WEA im Verhältnis zur Torsion nur eine untergeordnete Rolle spielt. Außerdem gilt es, das Modell durch weitere Versuche zu validieren und die beobachteten Abweichungen zwischen Versuch und theoretischem Modell aufzuklären.…”

Vorgespannte Trockenfugen für modulare Brücken unter zyklischer Belastung

“…Neben Brücken sind auch Windenergieanlagen (WEA) aufgrund der hohen Standardisierungsmöglichkeit der Turmsegmente ein Anwendungsgebiet [5–7]. Beide Bauwerksgruppen werden vorrangig durch nichtruhende, zyklische Belastungen beansprucht.…”

Beam-column modeling and seismic fragility analysis of a prestressed segmental concrete tower for wind turbines

“…The stresses due to transverse forces and torsion will be transferred by the contacting surface's friction, which is caused by the normal stresses resulting from external prestressing. Kang et al (2019) investigated the torsion resistance of segmental tower structures with current theory and numerical simulations. In wind turbine structures, the bending moment, other than shear or torsion, is usually the dominant factor.…”