An agent-based model to study customers' engagement with brands from a service-dominant logic perspective

We present an Agent-based Model to study customers' engagement with brands from a Service-Dominant Logic perspective. Customer Engagement has gained attention recently in the study of customer loyalty as a process that enables to understand and measure the impact of the depths of customers emotional responses to consumption situations on their intention to retain with a particular brand. However, there is no adequate research that deeply investigate the process of engagement, especially in dynamic, competitive and complex market environments. We address this research gap by creating an agent-based artificial market model. In doing so, we base our model on Service- Dominant Logic, which offers a novel lens to look at markets and their interactions and on the customer engagement process model of Bowden to implement customers engagement with a brand. This paper basically presents a logical discussion on the formulation of the model and some initial outcomes

Behaviour and Modelling of Reinforced Concrete Dapped-End Connections

Reinforced concrete dapped-end connections are commonly used in bridges, parking garages, industrial buildings, and other precast concrete infrastructure. Due to their characteristic shape, they typically feature an inclined corner crack at service loads arising from high stress concentrations in the re-entrant corner. At the same time, these connections transfer high shear forces through significantly reduced sections and are susceptible to brittle failures. For these reasons and major durability concerns stemming from penetration of corrosive agents, the modelling and monitoring of dapped-end connections remain a challenging problem. To deepen the understanding of this critical connection, this thesis provides analytical and experimental research on the behaviour and modelling of dapped-end connections. The thesis first presents a novel kinematics-based model to predict the strength of dapped-end connections failing along a re-entrant corner crack. The modelling framework is derived based on first principles - kinematics, equilibrium, and constitutive relationships – and facilitates the direct use of on-site measurable data to assess the strength of the connection. The model utilizes measured angles of the inclined crack as an input, and explicitly accounts for kinematic parameters such as the width and the length of the corner crack. Upon validating using a database of 47 tests from the literature, it is shown that the model captures well the peak resistance of dapped-end connections governed by the opening of the re-entrant corner crack, leading to an average experimental-to-predicted strength ratio of 1.10 and a coefficient of variation of 8.6%. In order to investigate the main failure modes of dapped-end connections, the thesis then presents experimental research on eight specimens. These specimens, which are among the largest in the literature, featured the orthogonal reinforcement layout. The main test variables are the amount of dapped-end reinforcement and the ratio of horizontal to vertical reinforcement area. The reinforcement amount is gradually increased to capture both flexural and shear failures of dapped-end connections. It was found that, for the same total area of dapped end reinforcement, connections featuring more horizontal reinforcement are slightly stronger. While the orthogonal layout did not provide sufficient crack control under service loads, all tests exhibited substantial rotation capacity, including the shear critical connections. Further experimental research on eight companion specimens featuring the diagonal reinforcement layout is then presented. The two sets of eight specimens had almost identical test parameters except for the reinforcement layout, allowing for direct comparisons. Crack displacements, crack patterns and the elongation of main dapped-end reinforcement are reported in detail via 56 continuous measurements of deformations. Comparisons of all sixteen specimens showed that, for the same amount of total dapped-end reinforcement, specimens with diagonal reinforcement are considerably stronger than the corresponding connections with orthogonal reinforcement layout. It was found that under both reinforcement layouts, the corner crack widths were in excess of typical code provisions under service conditions. Utilizing the observations and measurements of the experimental campaign, the kinematics-based model is further extended to predict the complete behaviour of dapped-end connections failing along a re-entrant corner crack. The model captures the pre-peak, peak and post-peak response, and explicitly predicts the deformations of the re-entrant corner crack under service conditions. The modelling assumptions are discussed in detail, and the crack width predictions are extensively validated using 24 tests from the literature. The results show good agreement between measured and predicted crack widths and peak capacity of dapped-end connections. As crack width predictions can be directly compared with on-site measurements, this offers a suitable framework for crack-based assessment of existing connections

An agent-based model to study customers' engagement with brands from a service-dominant logic perspective

We present an Agent-based Model to study customers' engagement with brands from a Service-Dominant Logic perspective. Customer Engagement has gained attention recently in the study of customer loyalty as a process that enables to understand and measure the impact of the depths of customers emotional responses to consumption situations on their intention to retain with a particular brand. However, there is no adequate research that deeply investigate the process of engagement, especially in dynamic, competitive and complex market environments. We address this research gap by creating an agent-based artificial market model. In doing so, we base our model on Service- Dominant Logic, which offers a novel lens to look at markets and their interactions and on the customer engagement process model of Bowden to implement customers engagement with a brand. This paper basically presents a logical discussion on the formulation of the model and some initial outcomes

Belgium

Deep beams with shear span-to-depth ratios a/d ≤ 2.5 are used to resist large shear forces due to their ability to develop direct strut action. To further enhance the shear strength and crack control of such members, researchers have studied the use of fibre-reinforced concrete (FRC). However, while this solution is promising, there is a need for rational mechanical models capable of predicting the shear strength of FRC deep beams in a sufficiently simple manner. This paper proposes such a mod-el based on first principles: kinematics, equilibrium and consti-tutive relationships. The proposed model simplifies an earlier two-parameter kinematic theory (2PKT) for the complete shear behavior of FRC deep beams, to predict the shear strength and components of shear resistance in a straightforward manner. The new simplified method (S2PKT) is validated by compar-ing the predicted results to 22 tests from the literature, as well as to FEM and 2PKT predictions. It is shown that the proposed simplified kinematic approach predicts well the shear strength with an average experimental-to-predicted shear strength ratio of 1.12 and a coefficient of variation of 12.9%. Furthermore, the model is used to discuss the effect of shear span-to-depth ratio and fibre volumetric ratio on the shear strength of FRC deep beams

Assessment of Failure Along Re-Entrant Corner Cracks in Existing RC Dapped-End Connections

peer reviewedReinforced concrete dapped-end connections are common in existing bridges and represent a critical component of the structure. Due to high stress concentrations in the re-entrant corner of the connection, dapped-ends typically feature inclined corner cracks that occur under service loads. Widening of these cracks due to material degradation and increasing loads can lead to yielding of the dapped-end reinforcement and subsequent failure of the connection. While most of the research devoted to predicting the peak resistance of such dapped-end connections has focused on the strut-and-tie and stress field modelling approaches, there remains a need for mechanical models that facilitate the direct use of on-site measurable data for assessing the strength of the connection. This paper presents the derivation of such a model based on first principles: kinematics, equilibrium and constitutive relationships. The model utilizes measured angles of the inclined crack as an input, and explicitly accounts for kinematic parameters such as the width and the length of the corner crack. A database of 47 tests from the literature featuring variable properties is used to validate the model. It is shown that the proposed approach captures well the peak resistance of dapped-end connections governed by the widening of the crack at the re-entrant corner, leading to an average strength experimental-to-predicted ratio of 1.10 and a coefficient of variation of 8.6%. Furthermore, the model is used to discuss the effect of the angle of the critical corner crack on the peak resistance of the connection.Modelling and Monitoring of Critical Connections in Aging Concrete Bridge

A Force-Based Fiber Beam-Column Element to Predict Moment-Axial-Shear Interaction of Reinforced Concrete Frames

The nonlinear analysis of large complex reinforced concrete (RC) frame structures with shear-critical members requires numerical approaches that combine high accuracy and computational efficiency. At the same time, existing modeling approaches either involve detailed and costly discretization of the deformations in the frame members (displacement-based approaches), or compromise on accuracy by greatly simplifying (or even neglecting) shear effects. This paper presents a novel nonlinear force-based fiber beam-column element that addresses both these challenges. The element is capable of capturing the complex moment-axial-shear interaction response of planar RC frames and walls, while at the same time requiring minimum discretization. The proposed formulation consists of two nested iterative procedures at the structure and sectional levels. The introduction of the sectional level procedure explicitly satisfies sectional equilibrium, which is not achieved in either existing displacement or force-based line element formulations. As a result, a stable convergence of all average strain, local crack strain, and slip strain components of the constitutive relationship is ensured. The efficiency and accuracy of the proposed element formulation is illustrated with the help of beam and frame tests from the literature

Investigation of shear and flexural failures of dapped-end connections with orthogonal reinforcement

Reinforced concrete dapped-end connections are commonly used in precast structures due to ease of construction and the possibility to maintain a reduced structural depth. However, dapped-end connections typically feature inclined corner cracks at service loads due to stress concentrations at the re-entrant corner. Furthermore, these connections transfer high shear forces through a significantly reduced section. Due to these reasons, two main failure modes of dapped-end connections are identified as failures along a re-entrant corner crack and shear failures in the dapped-end region. This paper investigates such failure modes through an experimental campaign consisting of eight large-scale dapped-end tests. The main test variables are the amount of dapped-end reinforcement and the ratio of dapped-end horizontal to vertical reinforcement area. Detailed deformation measurements and an in-depth discussion on the behavior of the test specimens is presented. The effect of the test variables on the strength, crack control and rotation capacity of dapped-end connections is investigated. It was found that, for the same total area of horizontal and vertical reinforcement, connections featuring more horizontal reinforcement are stronger. While the orthogonal dapped-end reinforcement layout did not provide sufficient crack control under service loads, all connections exhibited substantial rotation capacity, including the shear critical connections. The flow of internal forces of the test specimens is further studied with a kinematics-based model and nonlinear finite element analysis