Search results for "Infills"

Prediction of the out-of-plane response of infilled frames under seismic loads by a new fiber-section macro-model

2016

This chapter suggests that an extension of the capability of the traditional inplane macro-models to capture the simultaneous in-plane and Out-Of-Plane (OOP) response of infills. A new simplified macro-model for the assessment of both in plane and out-of-plane responses of infilled frames was developed and validated. The possibility to simulate the arching action is achieved by using distributed plasticity fiber-section elements, able to directly account for the coupling between axial load and bending moment. The arching action is explicitly introduced by the use of fiber-section beam-column elements, which can model the coupling between axial-load and bending moment. The model presented is…

Prediction of the additional shear action on frame members due to infills

2014

Infill masonry walls in framed structures make a significant contribution to the response under seismic actions. With special regard to reinforced concrete (RC) structures, it is known that internal forces modifications caused by the frame–infill interaction may be not supported by the surrounding frame because of the additional shear forces arising at the ends of beams and columns. Such additional forces may lead to the activation of brittle collapse mechanisms and hence their prediction is basic in capacity assessment, especially for structures that disregard the details for seismic zones. In this paper a parametric study is carried out addressed to the prediction of the shear forces ment…

Macroelement Model for In-Plane and Out-of-Plane Responses of Masonry Infills in Frame Structures

2018

A new macroelement model is presented in this paper for the simulation of the in-plane (IP) and out-of-plane (OOP) response of infilled frames subjected to seismic actions. The model consists of two diagonal, one horizontal, and one vertical struts. Each strut is represented by two fiber-section beam-column elements. The model is able to capture the arching action of the wall under an OOP load as well as the interaction between the IP and OOP actions. The proposed modeling approach is sufficiently simple and efficient that it can be used for the static or dynamic analysis of an entire structural system. An experimental validation has been carried out. A further numerical study performed wit…

Definition of diagonal Poisson's ratio and elastic modulus for infill masonry walls

2014

The prediction of the response of infilled frames through the simplified approach of substituting the infill with an equivalent pin-jointed strut is treated. In this framework the results of an experimental study for the mechanical characterization of different types of masonry infills having the aim of estimating strength, Young modulus and Poisson's ratio are presented. Four types of masonry were investigated and subjected to ordinary compressive tests orthogonally to the mortar beds and along the directions of the mortar beds. The experimental campaign confirmed the possibility of using an orthotropic plate model for prediction of the Poisson's ratio and Young modulus along the diagonal …

MODELLING IN-PLANE AND OUT-OF-PLANE RESPONSE OF INFILLED FRAMES THROUGH A FIBER MACRO-MODEL

2017

A new fiber macro-model for the simulation of combined in-plane and out-of plane response of infilled frames subjected to seismic actions is presented in the paper. The model consists of 4 pinned struts (two diagonals, one horizontal and one vertical) modeled with the nonlinear beam/column fiber-section elements available in OpenSees. The model is particularly suitable to predict the out-of-plane response as fiber-section elements can account for the coupling between axial load and bending moment occurring because of the arching mechanism developed by the infills beyond the first cracking. Moreover the model can account for the effect of the reciprocal damaging accumulated both in-plane and…

Cyclic response of masonry infilled RC frames: Experimental results and simplified modeling

2014

The recent large interest in nonlinear seismic analysis methods, static and dynamic, has required proper strategies of modeling based on reliable, and at the same time easy to use, constitutive laws for the structural elements. Regarding the behavior of framed structures, special attention has to be devoted to infills because of the key role they play in modifying overall stiffness, strength and ductility under seismic excitation. Pointing out the attention on this topic the paper discusses a criteria for modeling the structural behavior of infills based on a macromodeling approach, that is to say on the substitution of infills with diagonal pin jointed struts. Is here shown how multilinear…

Traditional vs. sliding-joint masonry infilled frames: Seismic reliability and EAL

2020

Abstract In reinforced concrete (RC) multi-storey buildings, the important role of the seismic interaction of structural frames with masonry infills has been revealed by several earthquakes and investigated by many authors. Recently, several innovative infill solutions have been proposed to mitigate such interaction, which could result in widespread damage in both the masonry and the RC structure and sometimes jeopardize the building stability and the occupants’ safety. One solution consists in the partitioning of the masonry infill into several sub-panels, relatively sliding along specific joints. This paper investigates the seismic assessment of this technological solution in the framewor…

OUT OF PLANE CAPACITY OF INFILLS AFTER IN PLANE LOADING: A PREDICTION ANALYTICAL MODEL

2019

Earthquakes produce on infills In-Plane (IP) and Out-Of-Plane (OOP) actions. The recent earthquakes have proved that the OOP collapse of infills is a diffused mechanism also in buildings designed to resist to seismic events in agreement to the most modern strategies. This fact makes the question arises about the safety of infills with respect OOP actions. The strong interaction between IP and OOP behaviour of infills traduces in a progressively reduction of the OOP strength. Further, only in few cases codes suggest adequate strategies to face this issue. For what above, in the paper the reduction of OOP strength because of the IP damage is studied by an extended numerical experimental campa…

An Updated Model of Equivalent Diagonal Strut for Infill Panels

2009

RC Masonry infilled frames: Experimental results and development of predictive techniques for the assessment of seismic response

2014

La presenza di tamponamenti in muratura all’interno delle maglie di strutture intelaiate induce, in presenza di azioni laterali, una sostanziale modificazione della risposta globale rispetto a quella dei telai nudi in termini di rigidezza, resistenza e capacità di spostamento. La tesi presenta i risultati di una campagna sperimentale su telai tamponati con diverse tipologie di muratura soggetti a prove di carico cicliche. Successivamente viene proposto un criterio per la modellazione semplificata del comportamento ciclico attraverso un macromodello a puntone diagonale equivalente. Una ulteriore indagine numerica è eseguita per valutare l'entità degli effetti locali dovuti all'interazione fr…