Interaction of ultrasonic waves with partially-closed cracks in concrete structures

Interaction of ultrasonic waves with partially-closed surface-breaking cracks in concrete structures has been studied. Measurements have been conducted on a reinforced concrete beam containing various mechanical-load-induced cracks and compared with the baseline measurements at those locations. Influence of crack width, incident angle of waves...

A mesoscale modelling perspective of cracking process and fracture energy under high strain rate tension

This paper presents a numerical modelling study on the simulation of the cracking process and fracture energy in concrete under high strain rate. To capture the stress wave effect and the damage evolution at the meso-length scale, both a homogeneous model with a millimetre-resolution mesh and an explicit heterogeneous mesoscale model with random...

Drop weight impact strengths of porous concretes investigated with a measurement technique using laser doppler velocimetry

Porous concrete is used in many applications that require permeability, noise absorption or thermal insulation. However, its response under dynamic loading is generally not considered. Porous concrete has a characteristic of forming multiple cracks and subsequently fracturing into small fragments when exposed to impact loading. Therefore, with...

Dynamic tensile resistance of concrete - Split hopkinson bar test

The behavior of concrete structures is strongly influenced by the loading rate. Compared to quasi-static loading, on meso and macro-scale concrete loaded by impact loading acts in a different way. First, there is a strain-rate influence on strength, stiffness, ductility, and, second, there are inertia forces activated which influence the...

Control of cracking in R.C. Structures: Numerical simulation of a squat shear wall

In this paper the behavior of a squat shear wall subjected to monotonic shear loading is investigated. The study fits into the experimental program driven by CEOS.fr on modeling of the behavior of the tested mocks-ups (monotonic and cycling loading-under prevented or free shrinkage). The shear wall has been analyzed with nonlinear finite element...

Results of monitoring large carbon fiber post-tensioning systems in a balanced Cantilever Bridge (Dintelharbour Bridge, The Netherlands)

Steel post-tensioning systems and stay cables are susceptible to corrosion. Carbon fiber systems are not. However, there was no experience on the long term behavior of such post-tensioned elements. Four external tendons (75 m long), stressed to a load of 2650 kN, were applied in a large balanced cantilever bridge and monitored for over 10 years....

Laboratory validation of MEMS-based sensors for post-earthquake damage assessment image

The evaluation of seismic damage is today almost exclusively based on visual inspection, as building owners are generally reluctant to install permanent sensing systems, due to their high installation, management and maintenance costs. To overcome this limitation, the EU-funded MEMSCON project aims to produce small size sensing nodes for...

Conservation of concrete structures in fib Model Code 2010

Chapter 9: Conservation of Concrete Structures forms part of the forthcoming fib new Model Code. As it is expected that the fib new Model Code will be largely completed in 2010, it is being referred to as fib Model Code 2010 (fib MC2010) and it will soon become available for wider review by the profession. This paper is part of this activity....

Corrosion monitoring for underground and submerged concrete structures - examples and interpretation issues

Since about 1980 Corrosion Monitoring Systems have been used in many concrete structures in aggressive environmentworldwide. While these systemswork properly in aboveground environment, some questions have arisen for submerged conditions, e.g. the outer sides of tunnels, piers in seawater or foundations in wet soil. One question concerns macro...