scholarly journals Behavior factor of concrete portal frames with dissipative devices based on carbon-wrapped steel tubes

2020 ◽  
Vol 19 (1) ◽  
pp. 553-578
Author(s):  
Andrea Vittorio Pollini ◽  
Nicola Buratti ◽  
Claudio Mazzotti
Keyword(s):  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Structural Members ◽  
Steel Tubes ◽  
Rc Structures ◽  
Behavior Factor ◽  
Entire Structure ◽  
Dynamic Analyses ◽  
Simplified Formula

AbstractThe key element characterizing the seismic vulnerability of existing prefabricated RC structures, not designed for earthquake actions, are friction-based connections between structural members; mainly those between beams and columns and beams and roofing beams. The paper discusses the effectiveness of dissipative connectors made of carbon wrapped steel tubes. In particular, it presents the results of Incremental Dynamic Analyses on portal frames, aimed at evaluating behavior factor values to be used in design. A simplified formula for estimating the behavior factor is also proposed. Results of nonlinear IDAs suggest that the introduction of these dissipative devices in friction-based beam-column joints provides an effective connection between structural members and, in addition, reduces the forces transmitted to columns, improving the seismic behavior of the entire structure.

scholarly journals Influence of Seismic Behavior Factor on the Design of Building Structures for Low Seismic Demands Regions

2015 ◽  
Vol 9 (1) ◽  
pp. 274-280
Author(s):  
Alejandro Hernández-Martínez ◽  
Andrés E. Ortíz-Vargas ◽  
Adrián D. García-Soto ◽  
Jesús G. Valdés-Vázquez ◽  
Mabel Mendoza-Pérez
Keyword(s):  
Structural Design ◽  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Elastic Response ◽  
Limit States ◽  
Behavior Factor ◽  
Initial Cost ◽  
Elastic Response Spectra ◽  
Final Design ◽  
Seismic Forces

The use of reduced seismic forces obtained from elastic response spectra analysis is a common practice for structural design purposes. This procedure is used: (a) To take advantage of the nonlinear behavior of the structural elements that conform the entire structure, and (b) To reduce the initial cost of the construction, allowing certain degree of damage if a severe earthquake occurs, but trying to avoid collapse with good structural design and construction detailing. In this paper, structural analyses were performed using several seismic reduction coefficients and the considered structures were designed for low seismic design regions according to the Mexico construction codes for both, serviceability limit states and ultimate limit states. Results show that the final design is strongly dependent on allowed interstory drift, associated to lateral displacements. Results also showed that, reducing significantly the seismic forces is not directly associated with a reduction in the initial cost of the structure, i.e., the final design for different seismic behavior factor may have similar seismic vulnerability.

Geometric Configuration Effects on Nonlinear Seismic Behavior of Concrete Gravity Dam

2018 ◽  
Vol 12 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Md. Imteyaz Ansari ◽  
Mohd Saqib ◽  
Pankaj Agarwal
Keyword(s):  
Nonlinear Dynamic ◽  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Geometric Configuration ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Dynamic Analyses

The effects of geometric configuration on the seismic vulnerability of concrete gravity dam are discussed in the present study. The seismic vulnerability of concrete gravity dams has been represented through fragility curves obtained through incremental dynamic analyses by considering their nonlinear dynamic behavior. Five different geometries of concrete gravity dams are considered and fragility analyses are carried out on the basis of Incremental Dynamic Analyses. The effect of smoothening of re-entrant corners in the geometry of high concrete gravity dam is also presented as a possible solution.

scholarly journals Seismic vulnerability study of Soltaniyeh dome using nonlinear static and dynamic analyses

2018 ◽  
Vol 10 (4) ◽  
pp. 367-380 ◽  
Author(s):  
Hossein Kalantari ◽  
Kiarash Nasserasadi ◽  
Seyyed Aliasghar Arjmandi
Keyword(s):  
Seismic Vulnerability ◽  
Dynamic Analyses ◽  
Nonlinear Static

Concrete Strength Variability in Italian RC Buildings: Analysis of a Large DataBase of Core Tests

2014 ◽  
Vol 597 ◽  
pp. 283-290 ◽  
Author(s):  
Angelo Masi ◽  
Andrea Digrisolo ◽  
Giuseppe Santarsiero
Keyword(s):  
Large Scale ◽  
Seismic Vulnerability ◽  
Concrete Strength ◽  
Discrete Distributions ◽  
Existing Buildings ◽  
Large Database ◽  
Public Buildings ◽  
Rc Structures ◽  
Actual Strength ◽  
Strength Variability

The knowledge of the materials’ mechanical properties is a preliminary and important step in the seismic vulnerability assessment of existing buildings. In RC structures, the compressive strength of concrete can have a crucial role on the seismic performance and is usually difficult to estimate. Major seismic codes prescribe that concrete strength has to be determined essentially from in-situ and laboratory tests. In some cases such estimation can be complemented by default values in accordance to standards at the time of construction, therefore analysing the actual concrete properties typically found in RC existing buildings realized in different periods can make available useful data. To this end, in this paper attention has been addressed to public buildings, namely schools and hospitals. A large database made up of about 1500 test results on concrete cores extracted from about 300 RC public buildings located in Basilicata region (Italy), has been prepared and analysed. The relationships between the actual strength values (mean and dispersion) and the construction period of buildings have been studied. Theoretical distributions to approximate the discrete distributions of strength values in different construction periods have been determined, thus providing relevant data for the structural assessment of individual buildings and, especially, for large scale vulnerability evaluations.

Corrosion effects on seismic capacity of reinforced concrete structures

2019 ◽  
Vol 37 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Antonio Bossio ◽  
Francesco Fabbrocino ◽  
Tullio Monetta ◽  
Gian Piero Lignola ◽  
Andrea Prota ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Seismic Behavior ◽  
Concrete Cover ◽  
Residual Service Life ◽  
Seismic Capacity ◽  
Rc Structures ◽  
Behavior Simulation ◽  
Cover Cracking ◽  
Rc Structure

AbstractRecently, corrosion prevention and monitoring of reinforced concrete (RC) structures became an important issue for seismic assessment of such kind of structures. Therefore, it is important to develop adequate models to represent material degradation into seismic behavior simulation of RC structures. Because of its effects, corrosion represents the most important form of degradation for materials and structures, both for wide diffusion and the amount of danger it presents. To understand the corrosion process is critical in order to design RC structures that are able to guarantee the required service life and in order to understand the residual service life and strength of an existing structure. The seismic behavior of a corroded framed RC structure is analyzed by means of push-over analyses, which allow understanding the development of the global behavior of the structure. Three different degrees of corrosion penetration were simulated, by means of the reduction of bars and stirrups’ diameters and concrete cover cracking and spalling, and three different configurations of corrosion, depending on the number of corroded frames and sides of the structural elements.

Influence of Spatial Variability of Seismic Shock on Steel Hall with Experimentally Determined Elasto-Plastic Parameters of Steel Material

2015 ◽  
Vol 744-746 ◽  
pp. 884-889
Author(s):  
Dorota Jasinska ◽  
Joanna M. Dulinska ◽  
Pawel Boron
Keyword(s):  
Spatial Variability ◽  
Seismic Excitation ◽  
Plastic Behavior ◽  
Structural Members ◽  
Steel Material ◽  
Dynamic Analyses ◽  
Seismic Shock ◽  
Wave Passage ◽  
Delay Dependent ◽  
Excitation Model

In the paper the influence of spatial variability of a seismic shock on an industrial steel hall was examined. Different models of seismic excitation were introduced. Firstly, a uniform seismic excitation model was applied, assuming identical motion of all supports of the hall. Then, a non-uniform excitation model was implemented. In that model subsequent points of the ground in the direction of wave propagation repeat the same motion with a certain time delay dependent on the wave velocity. Two direction of the wave passage were assumed: longitudinal (along the longer side of the hall) and transverse (along the shorter side of the hall). To guarantee proper nonlinear elasto-plastic behavior of the structure, the material parameters of the steel were determined experimentally. The dynamic analyses revealed that the response of the hall to the seismic shock was reported beyond the elastic range. Plastic effects appeared in some zones of the primary as well as the secondary structural members of the object, regardless of the excitation model. The model of non-uniform seismic excitation with transverse wave passage turned out to have the greatest impact on the dynamic response of the hall; the plastic strains obtained for that model were much greater than those obtained for other models. The transverse non-uniform excitation generated irreversible strains almost 3 times greater than the uniform excitation. The evolution of significant plastic effects was observed mainly for non-uniform excitations in the lower parts (girts and columns) of the hall, which were strongly affected by the different motions of the ground.

scholarly journals Axial Load Monitoring for Concrete Columns Using a Wearable Smart Hoop Based on the Piezoelectric Impedance Frequency Shift: A Feasibility Study

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yabin Liang ◽  
Zhicheng Ye ◽  
Qian Feng
Keyword(s):  
Axial Load ◽  
Concrete Columns ◽  
Structural Members ◽  
Entire Structure ◽  
Downward Shift ◽  
Structural Frame ◽  
Load Monitoring ◽  
Piezoelectric Impedance ◽  
Different Dimensions ◽  
The Stability

Concrete columns are critical in supporting the weight of an entire structural frame and also play a key role in force transferring among structural members. Therefore, integrity of the columns, especially their axial load bearing capacity, directly affects the stability and safety of the entire structure. In this study, a wearable smart hoop is designed to monitor the axial load of the concrete columns. The smart hoop measures the shift in impedance frequency of its integrated piezoelectric transducer and correlates the frequency to the structural state of the column. In order to validate the feasibility of the smart hoop, an experiment on two concrete columns with different dimensions is carried out. The smart hoop is installed on each column. Then, an increasing axial load was applied onto the specimen, and the admittance of the PZT patch is acquired under different load levels by using an impedance analyzer. Finally, frequencies corresponding to the peak and trough in the susceptance of the admittance signal are collected as the monitoring index to estimate the axial load variation on the specimen. The experimental results demonstrated a downward shift in frequency corresponding to an increase of axial load. The results validate the feasibility of the wearable smart hoop in monitoring axial load for concrete columns and show potential for retrofit on existing columns.

scholarly journals A Comparative Study of MCDM Methods Integrated with Rapid Visual Seismic Vulnerability Assessment of Existing RC Structures

2020 ◽  
Vol 10 (18) ◽  
pp. 6411 ◽  
Author(s):  
Ehsan Harirchian ◽  
Kirti Jadhav ◽  
Kifaytullah Mohammad ◽  
Seyed Ehsan Aghakouchaki Hosseini ◽  
Tom Lahmer
Keyword(s):  
Decision Making ◽  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Multiple Criteria Decision Making ◽  
Economic Loss ◽  
Assessment Method ◽  
Seismic Vulnerability Assessment ◽  
Rc Structures ◽  
Risk Levels ◽  
Rapid Visual Screening

Recently, the demand for residence and usage of urban infrastructure has been increased, thereby resulting in the elevation of risk levels of human lives over natural calamities. The occupancy demand has rapidly increased the construction rate, whereas the inadequate design of structures prone to more vulnerability. Buildings constructed before the development of seismic codes have an additional susceptibility to earthquake vibrations. The structural collapse causes an economic loss as well as setbacks for human lives. An application of different theoretical methods to analyze the structural behavior is expensive and time-consuming. Therefore, introducing a rapid vulnerability assessment method to check structural performances is necessary for future developments. The process, as mentioned earlier, is known as Rapid Visual Screening (RVS). This technique has been generated to identify, inventory, and screen structures that are potentially hazardous. Sometimes, poor construction quality does not provide some of the required parameters; in this case, the RVS process turns into a tedious scenario. Hence, to tackle such a situation, multiple-criteria decision-making (MCDM) methods for the seismic vulnerability assessment opens a new gateway. The different parameters required by RVS can be taken in MCDM. MCDM evaluates multiple conflicting criteria in decision making in several fields. This paper has aimed to bridge the gap between RVS and MCDM. Furthermore, to define the correlation between these techniques, implementation of the methodologies from Indian, Turkish, and Federal Emergency Management Agency (FEMA) codes has been done. The effects of seismic vulnerability of structures have been observed and compared.

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