Challenges in Modelling Reinforced Concrete Panels Subjected to Blast Load - A Critical Review

Reinforced concrete panels are widely used in modern facilities, and evaluating their blast loading capacity is vital for security-critical assets. Due to the high impulsive nature of blast loads, the response of reinforced concrete panels is characteristically different from that under static or low dynamic load conditions. The failure of individual components often initiates the blast load's destructive effects on the entire structure. The material breach can be caused by stress wave localized effects before the general structural response becomes significant. Numerical methods are one of the key methods for studying the behaviour of reinforced concrete panels under blast load. This paper aims to review the current state of practice in modelling reinforced concrete panels and predicting their blast capacity and failure mechanisms under blast load. The work addresses the research gaps associated with using advanced finite element modelling as compared to test results

MAT-722: EFFECT OF FIBER ORIENTATION ON THE BEHAVIOR OF CFRP CONFINED CONCRETE CYLINDERS

This paper presents the results of an ongoing experimental investigation examining the effect of fiber orientation and stacking sequence on the behavior of FRP-confined concrete. As part of the experimental study, 100 mm x 200 mm concrete cylinders were jacketed with carbon fiber reinforced polymer (CFRP) sheets and tested under pure axial compressive loading. The specimens were confined using various CFRP stacking sequences, with fibers oriented at 0⁰, 90⁰, and ±45⁰. Furthermore, within each stacking sequence, the numbers of layers was varied from 4 to 8 to examine the effect of number of plies on the behavior of the FRP-confined concrete cylinders. In addition, the research program included a companion set of CFRP coupons made from CFRP laminates having the same properties as the CFRP jackets used in the cylinder series. The preliminary results show that parameters such as fiber orientation, stacking sequence, and number of confinement layers have a direct impact on the strength, ductility and stress-strain behavior of CFRP confined concrete

Design of prestressed UHPFRC girder bridges according to Canadian Highway Bridge Design Code

Using ultra high performance fibre reinforced concrete (UHPFRC) can lead to the construction of structurally-efficient bridge superstructures that will require fewer girder lines and minimum maintenance resulting lower life cycle costs than conventional cycle performance. UHPFRC could enable major improvements over conventional or ordinary concrete (OC) bridges in terms of structural efficiency, durability and cost-effectiveness over the long term. A simplified design approach of concrete slab on UHPFRC girders bridge using the Canadian Highway Bridge Design Code is proposed. The use of UHPFRC results in a more efficient design of the superstructure through a significant reduction in number and size of girders and then weight of the superstructure. This reduction leads to significant reduction in the dead load on the substructure, which is very beneficial especially for the case of aging bridges.L'utilisation du b\ue9ton renforc\ue9 de fibres ultra-performant (BRFUP) peut permettre de construire des superstructures de pont efficientes d'un point de vue structural, qui n\ue9cessiteront un moins grand nombre de poutres et un entretien minimal, ce qui se traduira par des co\ufbts de cycle de vie moins \ue9lev\ue9s que la performance cyclique conventionnelle. Le BRFUP pourrait permettre des am\ue9liorations majeures par rapport aux ponts en b\ue9ton conventionnel ou ordinaire, pour ce qui est de l?efficacit\ue9 de la structure, de la durabilit\ue9 et du rapport co\ufbt-efficacit\ue9 \ue0 long terme. Nous proposons ici une approche simplifi\ue9e de la conception des ponts \ue0 dalle de b\ue9ton sur poutres en BRFUP utilisant le Code canadien sur le calcul des ponts routiers. L'utilisation du BRFUP a pour r\ue9sultat une conception plus efficiente de la superstructure via une r\ue9duction appr\ue9ciable du nombre et de la grosseur des poutres, par cons\ue9quent \ue9galement du poids de la superstructure. Cette r\ue9duction entra\ueene en retour une diminution significative de la charge permanente sur la substructure, laquelle se r\ue9v\ue8le des plus b\ue9n\ue9fique, plus particuli\ue8rement dans le cas des ponts vieillissants.Published online in 2013Peer reviewed: NoNRC publication: Ye

Numerical simulation of ground thermal response in Canadian seasonal frost regions to climate warming

Abstract To ensure that public infrastructure can safely provide essential services and support economic activities in seasonal frost regions, the design of their foundation systems must be updated and/or adapted to the impacts of climate change. This objective can only be achieved, if the impact of global warming on the soil thermal behaviour in Canadian seasonal frost regions is well-known and can be predicted. In the present paper, the results of a modeling study to assess and predict the effect of global warming on the thermal regimes of grounds in three Canadian seasonal frost regions (Ottawa, Sudbury, Toronto) are presented and discussed. The results show that future climate changes will significantly affect the soil thermal regimes in seasonal frost Canadian areas. The simulation results indicated a gradual loss in the frost penetration depth due to the climate change, in the three representative sites. The frost period duration will be shorter due to climate change in the three selected regions and will completely disappear in Ottawa and Toronto. However, the impact of climate change would not appear clearly in the first 40 years “up to 2060”. The response of the ground to the effect of climate change is a function of the geotechnical characteristics of the ground and the climate conditions. The numerical tool developed and results obtained will be useful for the geotechnical design of climate-adaptive transportation structures in Canadian seasonal frost areas

Nonlinear flexural analysis of reinforced concrete beam-column subjected to ultimate gravity loads combined with reinforcement corrosion: part I: sectional analysis

NRC publication: Ye

Nonlinear flexural analysis of reinforced concrete beam-column subjected to ultimate gravity loads combined with reinforcement corrosion: part II: finite element analysis

NRC publication: Ye

Influence of Dynamic Woody Debris Jam on Single Bridge Pier Scour and Induced Hydraulic Head

A woody debris jam around a bridge pier causes a change in flow structure and results in additional scour and an increase in the hydraulic head upstream of the pier, threatening its stability and safety. In the present paper, the spatio-temporal formation of a dynamic woody debris jam formed piece by piece of debris wood was used to investigate the influence of woody debris jams from a life-cycle perspective which included the processes of its formation, growth, failure, and rebirth. Several debris jams were formed in sequence during each experimental test. The results showed that the additional scour generated by the first woody debris jam compared with the scour depth without debris was a function of blockage ratio of the first debris jam, while the influence of the subsequent woody debris jams depended on their dimensions compared with the previous jam. When the subsequent debris jam’s dimensions were larger than the previous one, the scour further increased; otherwise, the scour remained constant and equal to the previous one. In addition, the debris-induced hydraulic head was analyzed and found to be correlated with the Froude number and the debris jam dimensions