scholarly journals Influence of Modelling Assumptions on the Seismic Risk of Industrial Precast Concrete Structures

2021 ◽  
Vol 7 ◽  
Author(s):  
Michele Egidio Bressanelli ◽  
Davide Bellotti ◽  
Andrea Belleri ◽  
Francesco Cavalieri ◽  
Paolo Riva ◽  
...  
Keyword(s):  
Seismic Risk ◽  
Precast Concrete ◽  
Time History ◽  
Experimental Tests ◽  
3D Models ◽  
Industrial Building ◽  
Linear Connections ◽  
Non Linear ◽  
Modelling Strategies ◽  
Modelling Assumptions

This research evaluates the influence of different modelling assumptions on the global and local seismic risk assessment of code-conforming precast reinforced concrete buildings, specifically single-story industrial buildings. In particular the modelling of the system mass, the overhead crane, the beam-to-column and roof-to-beam connections and the cladding system are investigated. For this purpose, a case study resembling a new industrial building designed in accordance with the current Italian building code was selected. Typical dowel beam-to-column connections were considered and the influence of various modelling strategies investigated: perfect hinges, linear elastic connections and non-linear connections with a degrading hysteretic force-displacement model which was calibrated from available data on experimental tests. Three different types of roof-to-beam connections were investigated removing the assumption of rigid diaphragm, namely hot-rolled, cold-formed and socket welded connections. Initially, simplified planar models of single frames were considered to evaluate the influence of the different modelling strategies, then 3D models of the entire building were analyzed. Multiple-stripe non-linear dynamic time history analyses allowed to evaluate displacements, drifts, deformations and ultimate curvatures of the main elements and connections for various intensity measure levels. The seismic risk was assessed in terms of failure rate considering the collapse of both the columns and of the connections. The results show that the beam-to-column connections fail right after reaching yielding due to their low displacement ductility, leading to the loss of support of the beam and therefore increasing the collapse rate of the investigated structural typology.

scholarly journals Fragility Analysis and Risk Assessment of Precast Concrete Frames with “Dry” Connections: A Comparative Study

2021 ◽  
Vol 1203 (3) ◽  
pp. 032045
Author(s):  
Chenhao Wu
Keyword(s):  
Energy Dissipation ◽  
Comparative Study ◽  
Seismic Risk ◽  
Social Impact ◽  
Precast Concrete ◽  
Time History ◽  
Fragility Functions ◽  
Concrete Frames ◽  
Energy Dissipation Devices

Abstract Precast concrete frames (PCFs) with "dry" connections and self-centering capacity have been proposed as a new kind of seismic protective structural system with characteristics of damage controllable mechanism, easy-assemblage and rapid repair speed. The damage mechanism of PCFs are concentrated at the panel zones under earthquake excitations, so as to avoid damage to beam and column components. Through reasonable design for the PCFs, not only the structural and life safeties can be guaranteed, but also the seismic loss and social impact can be minimized. This paper conducts a comparative study between PCFs with "dry" connections and conventional cast-in-situ concrete frame. A generalized beam-column connection analytical model is utilized to predict the seismic behaviour of PCFs with energy dissipation devices, with an emphasis on the opening behaviour at beam-column interfaces, the self-centering capacity provided by prestressed tendons and the hysteresis behaviour provided by energy dissipation devices. Prototype PCFs or cast in situ frame structures are designed to achieve similar deformation capacities in Chinese highly seismic fortification zone. Probabilistic seismic capacity analyses (PSCA) are conducted based on the results of probabilistic pushover analyses and Latin Hypercube Sampling. Incremental dynamic analysis method combined with nonlinear time history analyses are utilized to conduct probabilistic seismic demand analyses (PSDA). Fragility functions of different structural systems are derived based on the convolution of PSCA and PSDA. Finally, the seismic risk is evaluated based on the fragility functions and the developed Chinese seismic code compliant hazard functions. The results indicate that PCFs with energy dissipation devices can have lower seismic risk than conventional cast-in-site frames.

scholarly journals Seismic Risk Assessment of a Novel Self-Centering Precast Concrete Frame under Near-Fault Ground Motions

2020 ◽  
Vol 10 (18) ◽  
pp. 6510
Author(s):  
Fangfang Geng ◽  
Youliang Ding ◽  
Honglei Wu ◽  
Kang Yang
Keyword(s):  
Risk Assessment ◽  
Dynamic Analysis ◽  
Seismic Performance ◽  
Seismic Risk ◽  
Precast Concrete ◽  
Time History ◽  
Seismic Intensity ◽  
The Novel ◽  
Concrete Frame ◽  
Near Fault

The damage to structures caused by the velocity pulse effect of near-fault earthquake waves cannot be ignored, yet there are few studies on the risk assessment of seismic performance for precast concrete frame under near-fault earthquake waves. A novel self-centering precast concrete (SCPC) frame with hysteretic dampers is proposed to obtain great self-recovering and energy consumption characteristics. To accurately assess the seismic behaviors of the novel SCPC frame under the near-fault earthquake waves, a prototype structure is modelled and elastoplastic dynamic analysis is conducted at the design basis earthquake (DBE) and the maximum considered earthquake (MCE) seismic levels. Incremental dynamic analysis and the vulnerability analysis are performed. Annual and 50-year exceeding probabilities of the novel SCPC frame are calculated afterwards. In addition, the reinforced concrete (RC)frame and the traditional SCPC frame are also modelled, whose section sizes, reinforcements arrangement and seismic intensity are consistent with the novel SCPC frame. The dynamic time-history analysis at the two seismic levels are also carried out for two types of frames. The analysis results demonstrate that the novel SCPC frame has great seismic performance and low seismic risk possibility under the near-fault earthquakes loading.

PERILAKU STRUKTUR BAJA TIPE MRF DENGAN BEBAN LATERAL BERDASARKAN SNI 1726-2012 DAN METODE PERFORMANCE BASED PLASTIC DESIGN (PBPD)

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Nidiasari Jati Sunaryati Eem Ikhsan
Keyword(s):  
Pushover Analysis ◽  
Time History ◽  
Time History Analysis ◽  
Plastic Design ◽  
History Analysis ◽  
Non Linear ◽  
Static Pushover Analysis

Struktur rangka baja pemikul momen merupakan jenis struktur baja tahan gempa yang populer digunakan. Daktilitas struktur yang tinggi merupakan salah satu keunggulan struktur ini, sehingga mampu menahan deformasi inelastik yang besar. Dalam desain, penggunaan metode desain elastis berupa evaluasi non-linear static (Pushover analysis) maupun evaluasi non-linear analisis (Time History Analysis) masih digunakan sebagai dasar perencanaan meskipun perilaku struktur sebenarnya saat kondisi inelastik tidak dapat digambarkan dengan baik. Metode Performance-Based Plastic Design (PBPD) berkembang untuk melihat perilaku struktur sebenarnya dengan cara menetapkan terlebih dahulu simpangan dan mekanisme leleh struktur sehingga gaya geser dasar yang digunakan adalah sama dengan usaha yang dibutuhkan untuk mendorong struktur hingga tercapai simpangan yang telah direncanakan. Studi dilakukan terhadap struktur baja 5 lantai yang diberi beban gempa berdasarkan SNI 1726, 2012 dan berdasarkan metode PBPD. Hasil analisa menunjukkan bahwa struktur yang diberi gaya gempa berdasarkan metode PBPD mencapai simpangan maksimum sesuai simpangan rencana dan kinerja struktur yang dihasilkan lebih baik .

scholarly journals Record-to-record variability and code-compatible seismic safety-checking with limited number of records

2021 ◽  
Author(s):  
Fatemeh Jalayer ◽  
Hossein Ebrahimian ◽  
Andrea Miano
Keyword(s):  
Seismic Hazard ◽  
Linear Time ◽  
Time History ◽  
Time History Analysis ◽  
Seismic Safety ◽  
Hazard Curve ◽  
History Analysis ◽  
Non Linear ◽  
Seismic Hazard Curve ◽  
Cloud Analysis

AbstractThe Italian code requires spectrum compatibility with mean spectrum for a suite of accelerograms selected for time-history analysis. Although these requirements define minimum acceptability criteria, it is likely that code-based non-linear dynamic analysis is going to be done based on limited number of records. Performance-based safety-checking provides formal basis for addressing the record-to-record variability and the epistemic uncertainties due to limited number of records and in the estimation of the seismic hazard curve. “Cloud Analysis” is a non-linear time-history analysis procedure that employs the structural response to un-scaled ground motion records and can be directly implemented in performance-based safety-checking. This paper interprets the code-based provisions in a performance-based key and applies further restrictions to spectrum-compatible record selection aiming to implement Cloud Analysis. It is shown that, by multiplying a closed-form coefficient, code-based safety ratio could be transformed into simplified performance-based safety ratio. It is shown that, as a proof of concept, if the partial safety factors in the code are set to unity, this coefficient is going to be on average slightly larger than unity. The paper provides the basis for propagating the epistemic uncertainties due to limited sample size and in the seismic hazard curve to the performance-based safety ratio both in a rigorous and simplified manner. If epistemic uncertainties are considered, the average code-based safety checking could end up being unconservative with respect to performance-based procedures when the number of records is small. However, it is shown that performance-based safety checking is possible with no extra structural analyses.

scholarly journals USING 3D MODELS TO GENERATE LABELS FOR PANOPTIC SEGMENTATION OF INDUSTRIAL SCENES

2019 ◽  
Vol IV-2/W5 ◽  
pp. 61-68
Author(s):  
A. Nivaggioli ◽  
J. F. Hullo ◽  
G. Thibault
Keyword(s):  
Large Scale ◽  
Direct Reduction ◽  
3D Models ◽  
Industrial Building ◽  
True Negative ◽  
Industrial Companies ◽  
Learning Techniques ◽  
Great Performance ◽  
The Many ◽  
Public Datasets

<p><strong>Abstract.</strong> Industrial companies often require complete inventories of their infrastructure. In many cases, a better inventory leads to a direct reduction of cost and uncertainty of engineering. While large scale panoramic surveys now allow these inventories to be performed remotely and reduce time on-site, the time and money required to visually segment the many types of components on thousands of high resolution panoramas can make the process infeasible. Recent studies have shown that deep learning techniques, namely deep neural networks, can accurately perform panoptic segmentation of <i>things</i> and <i>stuff</i> and hence be used to inventory the components of a picture. In order to train those deep architectures with specific industrial equipment, not available in public datasets, our approach uses an as-built 3D model of an industrial building to procedurally generate labels. Our results show that, despite the presence of errors during the generation of the dataset, our method is able to accurately perform panoptic segmentation on images of industrial scenes. In our testing, 80% of generated labels were correctly identified (non null intersection over union, i.e. true positive) by the panoptic segmentation, with great performance levels even for difficult classes, such as reflective heat insulators. We then visually investigated the 20% of true negative, and discovered that 80% were correctly segmented, but were counted as true negative because of errors in the dataset generation. Demonstrating this level of accuracy for panoptic segmentation on industrial panoramas for inventories also offers novel perspectives for 3D laser scan processing.</p>

Real Time Loading Test Rig for Flight Control Actuators Under PHM Experimentation

2018 ◽  
Author(s):  
P. Chiavaroli ◽  
A. De Martin ◽  
G. Evangelista ◽  
G. Jacazio ◽  
M. Sorli
Keyword(s):  
Flight Control ◽  
Linear Models ◽  
Angular Position ◽  
Experimental Tests ◽  
Hydraulic Actuator ◽  
Loading Test ◽  
Pressure Transducers ◽  
Non Linear ◽  
Flight Controls ◽  
Servo Actuator

The article deals with the architecture, performance, and experimental tests of a test bench for servo-actuators used in flight controls. After the state of the art on the subject, the innovative architecture of the built bench is described, in which flight control actuator under test and load actuator are not in line but mounted perpendicularly. The model of the bench actuating systems is then presented, consisting of the servo-controlled hydraulic actuator, load cell, speed transducer, angular position transducer of the coupling and pressure transducers. For each of these components the nonlinear multi-physics mechatronic model is described, according to the adopted solutions. The adopted force control algorithm is discussed, showing the integrative compensation on the action line and proportional-derivative on the feedback, with speed feedforward. The experimental tests carried out on the bench under stalled conditions are also presented, whose results concerning time and frequency responses are compared with those obtained through the linearized and non-linear numerical model. Finally, the non-linear models of the flight control actuator under test, controlled in position, and of the loading servo-actuator of the bench are joined together, and the results of various simulations are described.

ANALYSIS OF ELASTIC IMPACT ON THIN SHELL STRUCTURES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1349-1354 ◽  
Author(s):  
SHIUH-CHUAN HER ◽  
CHING-CHUAN LIAO
Keyword(s):  
Differential Equation ◽  
Contact Force ◽  
Thin Shell ◽  
Time History ◽  
Dynamic Responses ◽  
Low Velocity Impact ◽  
Integro Differential Equation ◽  
Impact Process ◽  
Non Linear ◽  
The Impact

In this paper, a solution method for the response of a thin shell structure subjected to low velocity impact by a sphere is presented. The governing equation of the impact process is obtained by simultaneously solving the equations of motions for the sphere and shell. The derivation is based on the explicit expression of the displacement of the mid-surface of the shell under a single impulse load acting normal to apex of the shell. Incorporating the theory of convolution and Hertz contact law, a non-linear integro-differential equation in terms of the indentation of the contact, for the impact process is derived. The non-linear integro-differential equation is solved by the numerical scheme of Runge-Kutta method to obtain the time history of the contact force at the impact point of the shell. The contact force is then applied on the apex of the shell, the dynamic responses of the shell including the displacement and stress are obtained by the finite element method. The results are validated with the experimental test and numerical calculation published in the literatures. The effects of the radius and velocity of the impactor on the impact response is investigated through parametric study.

Dynamic Analysis of Frame-Support-Wall Structure with Openings on Floor

2011 ◽  
Vol 243-249 ◽  
pp. 1401-1404
Author(s):  
Yan Xia Ye ◽  
Jing Zhao
Keyword(s):  
Finite Element ◽  
Good Condition ◽  
Time History ◽  
3D Models ◽  
Mode Analysis ◽  
Wall Structure ◽  
Entire Structure ◽  
History Analysis ◽  
Dynamic Time ◽  
Support Wall

In order to study the influence of dynamic response of frame-support-wall structure with openings on floor, six 3D models with different radio of opening are made. According to the finite element mode analysis and dynamic time-history analysis, we know that the location of openings, the size of openings etc. are important to the performance of structure. In order to keep entire structure in good condition, we suggest that the rate of openings should be smaller than 6%~8%.

Experimental tests on multiple-slit devices for precast concrete panels

2018 ◽  
Vol 167 ◽  
pp. 420-430 ◽  
Author(s):  
Bruno Dal Lago ◽  
Fabio Biondini ◽  
Giandomenico Toniolo
Keyword(s):  
Precast Concrete ◽  
Experimental Tests ◽  
Concrete Panels
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