Dynamics of structures

A criterion is given for the convergence of numerical solutions of the Navier-Stokes equations in two dimensions under steady conditions. The criterion applies to all cases, of steady viscous flow in two dimensions and shows that if the local ' mesh Reynolds number ', based on the size of the mesh used in the solution, exceeds a certain fixed value, the numerical solution will not converge.

On the Navier-Stokes equations

Vibration serviceability of footbridges under human-induced excitation : a literature review

Advances in Computer Vision-Based Civil Infrastructure Inspection and Monitoring

This article implements the state‐of‐the‐art deep learning technologies for a civil engineering application, namely recognition of structural damage from images. Inspired by ImageNet Chall...

Deep Transfer Learning for Image-Based Structural Damage Recognition

Numerical evaluation of a novel crashworthy device for pier protection from barge impact

The article presents a two-dimensional fully coupled fluid–structure interaction model for simulating aeroelastic instabilities to evaluate and optimize the performance of flutter-based electromagn...

Numerical simulations of aeroelastic instabilities to optimize the performance of flutter-based electromagnetic energy harvesters:

Conventional inspections are based on intensive visual investigations. Though, the process of data capturing and post processing for extracting significant structural information, i.e. geometrical changes, is a complex task. Unmanned Aircraft Systems (UAS) offer a significant improvement of inspection and guarantee high quality images which are essential for reliable inspection results. The gathered data can be geo-referenced which offers the possibility of a highly accurate 3D modelling of structures in relation to a direct referenced visualization of detected changes or damages. The paper shows a case study of UAS-based monitoring of bridge pier deformations. An approach for a simplified extraction of basic geometries from 3D point clouds for a quantification of deformations generated from aerial images by the use of Computer Vision methods is introduced. A reproducible workflow for the recording, processing and evaluation of a change detection and condition documentation is provided with regard to Building Information Modelling (BIM).

BIM related workflow for an image-based deformation monitoring of bridges

From Aerial Photography to 3-Dimensional Inspection of Bridges

Stonecutters Bridge and Sutong Bridge in China have pushed the world record for main span length of cable-stayed bridges to over 1000 m. The design of these bridges, both located in typhoon-prone regions, was strongly influenced by wind effects during erection. Rigorous wind tunnel test programmes were devised and executed to determine the aerodynamic behaviour of the structures in the most critical erection conditions. Testing was augmented by analytical and numerical analyses to verify the safety of the structures throughout construction and to ensure that no serviceability problems would affect the erection process. This paper outlines the wind properties assumed for the bridge sites, the experimental test programme with some of its results, the dynamic properties of the bridges during free-cantilevering erection and an assessment of their aerodynamic performance. The similarities and some revealing differences between the two bridges in terms of their dynamic response to wind action are also discussed.

Guido Morgenthal

Papers

Numerical evaluation of a novel crashworthy device for pier protection from barge impact

Numerical simulations of aeroelastic instabilities to optimize the performance of flutter-based electromagnetic energy harvesters:

BIM related workflow for an image-based deformation monitoring of bridges

From Aerial Photography to 3-Dimensional Inspection of Bridges

Behaviour of very long cable-stayed bridges during erection