Title Participants Abstract "Spared internal but impaired external reward prediction error signals in major depressive disorder during reinforcement learning" "Jasmina Bakic, Gilles Pourtois, Marieke Jepma, Romain Duprat, Rudi De Raedt" "BACKGROUND: Major depressive disorder (MDD) creates debilitating effects on a wide range of cognitive functions, including reinforcement learning (RL). In this study, we sought to assess whether reward processing as such, or alternatively the complex interplay between motivation and reward might potentially account for the abnormal reward-based learning in MDD.METHODS: A total of 35 treatment resistant MDD patients and 44 age matched healthy controls (HCs) performed a standard probabilistic learning task. RL was titrated using behavioral, computational modeling and event-related brain potentials (ERPs) data.RESULTS: MDD patients showed comparable learning rate compared to HCs. However, they showed decreased lose-shift responses as well as blunted subjective evaluations of the reinforcers used during the task, relative to HCs. Moreover, MDD patients showed normal internal (at the level of error-related negativity, ERN) but abnormal external (at the level of feedback-related negativity, FRN) reward prediction error (RPE) signals during RL, selectively when additional efforts had to be made to establish learning.CONCLUSIONS: Collectively, these results lend support to the assumption that MDD does not impair reward processing per se during RL. Instead, it seems to alter the processing of the emotional value of (external) reinforcers during RL, when additional intrinsic motivational processes have to be engaged." "Spared internal but impaired external reward prediction error signals in major depressive disorder during reinforcement learning: B akic et al" "Jasmina Bakic, Gilles Pourtois, Marieke Jepma, Romain Duprat, Rudi De Raedt" "Background: Major depressive disorder (MDD) creates debilitating effects on a wide range of cognitive functions, including reinforcement learning (RL). In this study, we sought to assess whether reward processing as such, or alternatively the complex interplay between motivation and reward might potentially account for the abnormal reward-based learning in MDD. Methods: A total of 35 treatment resistant MDD patients and 44 age matched healthy controls (HCs) performed a standard probabilistic learning task. RL was titrated using behavioral, computational modeling and event-related brain potentials (ERPs) data. Results: MDD patients showed comparable learning rate compared to HCs. However, they showed decreased lose-shift responses as well as blunted subjective evaluations of the reinforcers used during the task, relative to HCs. Moreover, MDD patients showed normal internal (at the level of error-related negativity, ERN) but abnormal external (at the level of feedback-related negativity, FRN) reward prediction error (RPE) signals during RL, selectively when additional efforts had to be made to establish learning. Conclusions: Collectively, these results lend support to the assumption that MDD does not impair reward processing per se during RL. Instead, it seems to alter the processing of the emotional value of (external) reinforcers during RL, when additional intrinsic motivational processes have to be engaged." "Evaluation of the FIB bulletin 14 design guideline for external TRC bending reinforcement" "Svetlana Verbruggen, Jan Wastiels, Tine Tysmans, Sven De Sutter, Maciej Wozniak" "Due to their advantages related to fire safety and their relatively low cost, Textile Reinforced Cement (TRC) composites are emerging as external reinforcing materials for concrete structures. The current design guidelines for external reinforcement are mostly elaborated for the Carbon Fibre Reinforced Polymers (CFRP) material solutions. Considering the major differences between both the CFRP and TRC materials, the validity of these CFRP design guidelines for the TRC external reinforcement should be verified and eventually the design rules should be adapted. This paper contributes to the evaluation of the European FIB bulletin 14 design guideline for TRC by comparing 2.3-meter-span externally reinforced concrete beams designed according to the FIB bulletin 14 with experimental results from four point bending tests. The results show that the design guidelines underestimate the ultimate load by almost 20 % due to a difference in occurring failure mode (experimental: failure in composite action; predicted: failure by loss of composite action). These observations indicate that the FIB design guideline cannot be used to accurately predict the bending behaviour of a TRC-reinforced beam and thus that adapted calculation techniques are needed." "Comparison between TRC and CFRP as external reinforcement for plain concrete beams" "Svetlana Verbruggen, Jan Wastiels, Tine Tysmans, Silke Puystiens" "Strengthening and repairing existing structures is often more economical and sustainable than demolishing and afterwards rebuilding them. Concrete structures can be strengthened using high performance glass fibre Textile Reinforced Cements (TRC) as an external reinforcement. Until now no evaluation of the cracking behaviour of this system with respect to the established technique of CFRP strips is reported. This paper presents the experimental comparison between both techniques, based on four point bending tests with third point loading, where the crack pattern evolution is monitored with Digital Image Correlation (DIC). A wider TRC external reinforcement retrains the high initial stiffness up to a higher load and reduces the crack widths in comparison with the CFRP solution, designed to meet an equal failure load. These advantages can be attributed to the crack bridging capacity of the external reinforcement." "Characterization of mechanical performance of concrete beams with external reinforcement by acoustic emission and digital image correlation" "Svetlana Verbruggen" "Characterization of the damage mechanisms of a structure in real time is a challenging engineering task. Several nondestructive testing techniques have been used according to their capabilities and the target problem. Acoustic emission (AE) is one of them, enabling to record the elastic waves due to propagating cracks and to evaluate the criticality of the condition. Information on the location of the cracking sources, their mode and severity can be supplied by proper analysis of AE parameters and trends. However, in certain cases assumptions are inevitable and many times the experience of the user is essential in order to explain the AE trends according to the actual damage mechanism occurring at the moments when AE changes are registered. In the present case AE is used for monitoring the bending failure of concrete beams reinforced by external layers of different composite materials. The monitoring is complemented by Digital Image Correlation (DIC) which gives a clear depiction of the surface strain field and its transient changes according to stress redistribution which occurs after fracture moments. Results of AE are thus benchmarked and certain trends reliably attributed to specific processes. Conclusions on the mechanical performance of the different reinforcing materials on the beams, which is another major aim of the study, are also drawn." "A new composite for external reinforcement: Steel Cord Reinforced Polymer" "Wine Figeys, Luc Schueremans, Dionys Van Gemert" "Today, mostly steel plates and carbon fibre reinforced polymers (CFRP) are used as external reinforcement. This paper deals with a new material that can be used as external reinforcement: steel cord reinforced polymer (SCRP). It consists of thin high-strength steel fibres embedded in a polymer matrix. This innovative material combines the advantages of steel and carbon fibres. The material cost of SCRP is relatively low and the laminate preserves the flexibility. The applicability of the new material as external reinforcement is investigated." "The influence of externally bonded longitudinal TRC reinforcement on the crack pattern of a concrete beam" "Svetlana Verbruggen, Jan Wastiels, Olivier Remy, Sébastien Michez" "Often it is more economical to strengthen or repair structures than to demolish and afterwards rebuild them. Several strengthening and repair systems are commercially available at the moment; one of the most common systems is the externally bonded carbon fibre reinforced polymer (CFRP) strip. This interesting system shows however some drawbacks like its bad resistance to high temperatures and the high cost of the used carbon fibres. The use of strips made of glass fibre reinforced inorganic phosphate cement (IPC) can possibly offer an answer to these drawbacks. High fibre contents (20 % in volume and more), which can be obtained with fibre mats, allow for thin and light strips, which are easy to install. This paper experimentally investigates the influence of external longitudinal reinforcement, made of glass fibre reinforced IPC, on the crack pattern and cracking moment of a plain concrete beam. During a four point bending test, digital image correlation (DIC) monitors the displacements, and thus strains, at the side and the bottom surfaces of the beams in the constant moment zone. In this way, the crack pattern evolution can be visualized. An important observation during these tests is that the first cracks appear at the calculated cracking moment, but that the beams retain their high initial bending stiffness up to an applied moment that is ap-proximately 50 % higher than the calculated one. This phenomenon can be ascribed to the restraining effect of the IPC strip on crack opening and propagation." "Externally applied FRP reinforcement for concrete structures" "EAR fib Working Group, Stijn Matthys" "Fib report on design of concrete members strengthened with externally applied reinforcement" "Stijn Matthys, Thanasis Triantafillou" "Blast mitigation of reinforced concrete hollow core slabs using CFRP as externally bonded reinforcement" "Azer Maazoun, Stijn Matthys, Bachir Belkassem, David Lecompte, John Vantomme" "One of today's state-of-the-art techniques for strengthening of reinforced concrete structural elements is the use of carbon fiber reinforced polymer (CFRP) composite strips as externally bonded reinforcement (EBR). This is justified for quasi-static loads by the high strength, light weight and excellent durability characteristics of CFRP EBR in combination with their ease of application. The present paper deals with the performance of the technique for blast loads. This paper investigates the usefulness of CFRP EBR to improve the flexural resistance capacity of reinforced concrete hollow core slabs (RCHCS) under blast loads. In order to achieve this objective, three simply supported RCHCS with a compression layer, were subjected to an explosion test. The obtained experimental results of the RCHCS without and with EBR are presented and discussed with the aim of evaluating the influence of EBR on the blast response of the RCHCS. A numerical analysis is also carried out using the finite element software LS-DYNA to complement the experimental results."