Search results for " Structural"

Proceedings of MDP2007 international Symposium on Recent Advances in Mechanics (structural/solid) Dynamical Systems (deterministic/stochastic) Probab…

2009

Prediction of concrete materials compressive strength using surrogate models

2022

Using soft computing methods could be of great interest in predicting the compressive strength of Ultra-High-Performance Fibre Reinforced Concrete (UHPFRC). Therefore, this study developed four soft computing techniques. The models are the Linear- relationship (LR), pure quadratic, M5P-tree (M5P), and artificial neural network (ANN). The models were trained and developed using 306 datasets comprising 11 input parameters, including the curing temperature (T), the water-to-cement ratio (w/c), silica fume (SF), cement content (C), fiber content (Fb), water (W), sand content (S), superplasticizer (SP), fiber aspect ratio (AR) and curing time (t). Experimental results were used and compared to t…

A model for SFRC beams without shear reinforcement

2008

In this paper a physical model, for the prediction of ultimate shear strength of Steel Fibers Reinforced Concrete (SFRC) beams is developed from the plastic Crack Sliding Model (CSM) introduced by Zhang (1997), based on the hypothesis that cracks can be transformed into yield lines. In this work the effectiveness factors are recalculated for SFRC beams and some further developments are introduced in the CSM, taking into account the fundamental post cracking tensile strength contribute of SFRC. The proposed model is validate by a large set of tests collected in literature and some numerical analyses were carried out to show the influence of fibers on the failure beams mode.

Case Study of the Structural Behavior of a Catalan Bricks Masonry Vault

2015

Catalan vaults are a peculiar type of low thickness vaulted brick masonry structure. Knowledge of load-deflection response and load bearing capacity are important aspects to consider with the aim of preserving these structural members as part of the cultural heritage. In order to investigate these aspects, complete knowledge of the constituent materials and geometry (dimension, thickness, constructive section) is necessary in such a way as to predict the load-deflection response and the effective load-carrying capacity; the latter can be determined utilizing simplified models (limit analysis) or by means of a numerical analysis (finite element method). With this aim, the structural behaviou…

Flexural behavior of R.C. columns externally wrapped with FRP sheets

2012

In the present paper the compressive and flexural behavior of R.C. columns externally wrapped with FRP layers is examined. The investigation refers to a short compressed R.C. member having circular transverse cross-section and reinforced with longitudinal bars and transverse hoops or spirals. A first phase of the investigation was addressed to describing the constitutive laws of constituent materials (confined concrete core, steel bars in compression and in tension, FRP in tension). The second phase of the research was addressed to deriving the compressive and flexural responses in terms of load-axial shortening curves and momentaxial force interaction domain, to be compared with experiment…

A technique for the dynamic identification of civil systems

2012

A statistical moments based approach for the dynamic identification of civil structures

2012

In recent years, interest in developing identification techniques that are valid in the case of unmeasured input has increased. In this field some interesting parametric approaches have been proposed. Nevertheless, the improvement of the available techniques or the formulation of new techniques is desirable. In this paper a time domain dynamic identification approach based on the statistical moments of the response of civil structures under base random excitations is discussed. Two types of models are used: the classically damped models characterized by mass proportional damping and the so-called “potential models” which are non linear in damping and stiffness. By applying the Itô different…

RC beams retrofitted by FRP oriented in any direction: Influence of the effectiveness factors

2022

Shear strength of FRP-retrofitted RC beams is usually influenced by different brittle failure modes characterizing the collapse of the FRP reinforcement. The most significant analytical models for assessing the shear strength of FRP-retrofitted RC beams reflect the effect of brittle failure through an effectiveness factor “R”, which reduces the ultimate tensile strength of FRP. The brittle collapse of FRP reinforcement often leads to a lower shear contribution by steel stirrups due to hindering of the yielding of all stirrups involved by critical cracking. Some analytical models consider this phenomenon introducing a further effectiveness factor “r”, which reduces the yielding strength of s…

Out-of-Plane fragility of In-Plane damaged unreinforced masonry infills in low rise reinforced concrete buildings

2022

Unreinforced masonry (URM) is commonly used to make infill walls in reinforced concrete (RC) frame buildings. Such infill walls are highly vulnerable to out-of-plane (OOP) seismic loading and this can result in huge economic losses and human casualties. Therefore, fragility assessment of URM infill walls under seismic loads is important in view of performing large-scale risk analysis. In this paper, OOP fragility functions are provided based on a numerical investigation supported by a macro-element model. The fragility is calculated assuming the uncertainty in the geometric and mechanical properties of infills instead of the variability in the seismic input. Further, the effect of in-plane …

Revealing the nature of metakaolin-based concrete materials using artificial intelligence techniques

2022

In this study, a model for the estimation of the compressive strength of concretes incorporating metakaolin is developed and parametrically evaluated, using soft computing techniques. Metakaolin is a component extensively employed in recent decades as a means to reduce the requirement for cement in concrete. For the proposed models, six parameters are accounted for as input data. These are the age at testing, the metakaolin percentage in relation to the total binder, the water-to-binder ratio, the percentage of superplasticizer, the binder to sand ratio and the coarse to fine aggregate ratio. For training and verification of the developed models a database of 867 experimental specimens has …