Search results for "Structural engineering"
showing 10 items of 1998 documents
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…
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 …
Influence of wall-to-floor connections and pounding on pre- and post-diction simulations of a masonry building aggregate tested on a shaking table
2023
AbstractThis paper presents numerical simulations within the frame of the project SERA—AIMS (Seismic Testing of Adjacent Interacting Masonry Structures). The study includes blind pre-diction and post-diction stages. The former was developed before performing the shaking table tests at the laboratory facilities of LNEC (Lisbon), while the latter was carried out once the test results were known. For both, three-dimensional finite element models were prepared following a macro-modelling approach. The structure consisted of a half-scaled masonry aggregate composed by two units with different floor levels. Material properties used for the pre-diction model were based on preliminary tests previou…
Simulation of blind pre-diction and post-diction shaking table tests on a masonry building aggregate using a continuum modelling approach
2023
AbstractMasonry buildings of historical centres are usually organized within aggregates, whose structural performance against seismic actions is challenging to predict and constitutes still an open issue. The SERA—AIMS (Seismic Testing of Adjacent Interacting Masonry Structures) project was developed to provide additional experimental data by testing a half-scale, two-unit stone masonry aggregate subjected to two horizontal components of dynamic excitation. In this context, this paper investigates the reliability of the modelling approach and the assumptions adopted to generate a three-dimensional continuum finite element model. The work involves two stages, namely a blind pre-diction and a…
Properties of blended mortars produced with recycled by-products from different waste streams
2023
The construction industry encounters significant challenges in effectively managing solid waste produced during the extraction and production of building materials. In different countries, slurry waste generated from granite and marble processing industries, such as glass industry waste, constitutes a considerable portion of the total solid waste. Its undesirable disposal is causing unprecedented environmental damage. Using these non-biodegradable wastes to produce building materials would reduce the environmental burden and contribute to sustainable construction. This study, in detail, investigates the feasibility of utilizing Granite Powder (GP), Ground Granite Powder (GGP), and Ground Gl…
Push-Over Analysis of RC Frame with Corroded Rebar
2019
Abstract As known, the Italian building heritage largely consists of reinforced concrete frames designed before the ‘80s, which are, in many cases, built in the absence of specific anti-seismic criteria. Moreover, many of them, today, are characterized by bad structural conditions. Moreover, the problem of the structural conditions of the existing buildings, and their residual strength capacity, is often linked to the deterioration induced by the corrosive phenomena, which end up having a big impact on steel rebar mechanical properties. In this work, in order to investigate the influence of corrosion-damage on seismic response of existing reinforced concrete structures, a study has been car…
A closed form procedure for the design of longitudinal bars in RC sections subjected to axial load and biaxial bending
2020
This paper presents an analytical procedure for the design of the longitudinal reinforcement in reinforced concrete rectangular sections subjected to axial load and biaxial bending moment. The integration of the equilibrium equations is performed in analytical form for the case of uniaxial moment, including the effect of the reinforcement placed on the sides of the section and adopting code-based constitutive laws for steel and concrete. The strength domain of the section is calculated in closed form for the case of only main steel and in simplified form when including the reinforcement disposed on the side. Additionally, a formulation is proposed for the interaction domain of the two compo…
Development of a software package with GUI for the evaluation of monolithicity factors of RC jacketed columns
2023
The design of reinforced concrete (RC) jacketing for retrofitting substandard columns is a common practice when approaching the structural rehabilitation design of existing structures. In this framework, international technical codes suggest to assume the hypothesis of monolithic section and finally affecting the deduced performances by some empirical factors, known in the literature as monolithicity factors. The assessment of these coefficients is a difficult task, and only some rough assumptions can be found in the modern codes. This paper presents the development of a software package able to perform the static non-linear analysis of RC jacketed columns and evaluating the actual value of…