Influence of different mechanical column-foundation connection devices on the seismic behaviour of precast structures

2016 ◽  
Vol 14 (12) ◽  
pp. 3485-3508 ◽  
Author(s):  
Bruno Dal Lago ◽  
Giandomenico Toniolo ◽  
Marco Lamperti Tornaghi
2021 ◽  
Author(s):  
Marco Bovo ◽  
Lucia Praticò ◽  
Marco Savoia

Abstract The existing precast reinforced concrete structures, especially those not specifically designed against the earthquakes, have proved to be inadequate to withstand the remarkable seismic demands related to the presence of heavy roof elements. In fact, the cantilever columns entailing large top displacements and the poor devices adopted to connect different precast elements have shown high sensitivity to seismic actions. After the lesson learned from the recent Emilia earthquake of May 2012, causing many collapses and severe damage, reliable seismic design criteria have been established for the design of new precast structures and for the strengthening of the existing ones. Despite this, a large percentage of the existing precast buildings in the Italian territories actually has not been object of interventions and remains in an unsafe condition with regards to the seismic actions. In this context, the methods for a rapid seismic assessment can be very helpful both to estimate the current safety level of large building stocks and to plan the necessary strengthening interventions, possibly at the wide scale of an industrial area. To this aim, the paper proposes a new method, named PRESSAFE-disp (PRecast Existing Structure Seismic Assessment by Fast Evaluation-displacements), for the fast evaluation of the fragility curves of precast structures. The method follows the approach of the PRESSAFE method, but different damage criteria have been introduced in order to take into account the relative displacements and the sliding between different precast elements. The damage criteria considered, applicable to both structural elements and perimeter cladding elements conceived as non-structural elements, have been properly selected in order to capture the damage mechanisms observed during the several building inspections conducted by the authors in the aftermath of the 2012 Emilia earthquakes. In the present configuration, the method allows a comprehensive explanation of the seismic behaviour of the existing precast buildings and could be effectively adopted, for example, in earthquake loss estimations and seismic risk assessments of large Italian industrial areas, as well as of wide seismic-prone territories of the Mediterranean area.


2017 ◽  
Vol 3 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Reza Jamalpour ◽  
Masood Nekooei ◽  
Abdolreza Sarvghad Moghadam

Connections in MRFs are the most important members and seismic behaviour is affected by function of beam column connections as well as column foundation connections. If the connections are able to provide the required ductility and efficiency against the seismic excitation, the seismic capacity of the MRF performed by these connections will be affected. SMAs have recently been used as a tool to dissipate energy in structures. So far, using of them for column foundation connections has been applied much less. In this paper, SMAs have been introduced and an innovated column foundation connection equipped with SMA has been suggested. Micro and macro behaviour of the connection has been studied and it was applied in sample MRF. Seismic response of the MRF under different earthquakes by equipping the connection with steels/SMAs bars have been studied and compared. Finally, results indicated that MRF with this connection showed proper seismic performance.


Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.


Author(s):  
A. Sandoli ◽  
G. P. Lignola ◽  
B. Calderoni ◽  
A. Prota

AbstractA hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions. Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building’s class has been chosen as an Intensity Measure to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minimum value of PGAs defined for each building class. To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber macroseismic intensity scale has been used and the corresponding fragility curves developed. Results show that the proposed building’s classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods.


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