Brücken mit vorgespannter Stahlunterspannung

Bridges suspended by prestressed steel tubes. The structural system of suspended girders was used for bridge structures as early as the beginning of the 19th century. Because of the technological advancements in the field of prestressing and due to the high structural efficiency, this structural concept has regained significance in recent years. A promsing application consists of the combination of a simple suspended steel structure with prestressing technology

Two bridges with composite prestressed tension chord

the bridges over the river Capriasca (1996) and over the river Ticino (1997) are characterised by the application of an innovative structural system. The central part of the main span of both bridges is constituted by the bridge concrete deck with two longitudinal stiffening girders, constituted by polygonal steel members that contain two prestressing tendons each

Eléments sans armature d'effort tranchant

Cours d'introduction à la norme SIA 262

Introduction à la norme SIA 262

Cours d'introduction à la norme SIA 262

Ponts avec un système statique innovant

In: SIA D 0160, Progrès dans la conception des ouvrages en béton (1999), p.33- 3

Punching shear strength of reinforced concrete slabs without transverse reinforcement

A mechanical explanation of the phenomenon of punching shear in slabs without transverse reinforcement is presented on the basis of the opening of a critical shear crack. It leads to the formulation of a new failure criterion for punching shear based on the rotation of a slab. This criterion correctly describes punching shear failures observed in experimental testing, even in slabs with low reinforcement ratios. Its application requires the knowledge of the load-rotation relationship of the slab, for which a simple mechanical model is proposed. The resulting approach is shown to give better results than current design codes, with a very low coefficient of variation (COV). Parametric studies demonstrate that it correctly predicts several aspects of punching shear previously observed in testing as size effect (decreasing nominal shear strength with increasing size of the member). Accounting for the proposed failure criterion and load-rotation relationship of the slab, the punching shear strength of a flat slab is shown to depend on the span of the slab, rather than on its thickness as often proposed

Schubfestigkeit und Durchstanzen von Platten ohne Querkraftbewehrung

A general calculation model is developed and described starting from the effective load-carrying mechanisme of edge- and point supported (punching shear) slabs. This leads to a simplified and practical design process for shear. This method, originally developed for the new Swiss code SIA 262, is explained and compared to the DIN 1045-1 code through parametric studies and application examples