scholarly journals Rubble Stone Masonry Buildings with Cement Mortar: Base Shear Seismic Demand Comparison for Selected Countries Worldwide

2021 ◽  
Vol 7 ◽  
Author(s):  
Martijn Schildkamp ◽  
Stefano Silvestri ◽  
Yoshikazu Araki
Keyword(s):  
Limit State ◽  
Stone Masonry ◽  
Seismic Load ◽  
Ultimate Limit State ◽  
Seismic Demand ◽  
Masonry Buildings ◽  
Base Shear ◽  
Mass System ◽  
Starting Point ◽  
Rubble Stone Masonry

Full base shear seismic demand analyses with calculated examples for heavy stone masonry buildings are not present in the literature. To address this shortcoming, analyses and calculations are performed on nominally reinforced rubble stone masonry house and school designs, as typically built in Nepal. The seismic codes are literally applied for countries where the technique is still allowed (Nepal, India, China, Tajikistan, Iran, Croatia), or should be reintroduced based on current practices (Pakistan, Afghanistan, Turkey). First, this paper compares the base shear formulas and the inertia forces distributions of these codes, as well as material densities, seismic weights, seismic zoning, natural periods of vibration, response spectra, importance factors and seismic load combinations. Large differences between approaches and coefficients are observed. Then, by following Equivalent Lateral Force-principles for Ultimate Limit State verifications (10%PE50y), the base shear and story shears are calculated for a design peak ground acceleration of 0.20 g, as well as the effects of critical load combinations on the forces and moments acting on the lateral-resisting elements. It is concluded that Pakistan has the most tolerant code, Nepal represents an average value, whereas India and China are most conservative toward the case study buildings. Overall, it is observed that heavy-masonry-light-floor systems with negligible diaphragm action behave different under seismic motion than most other building typologies. Given the observations in this paper, the applicability of conventional ELF, S-ELF and S-Modal methods for heavy masonry buildings is questionable. The codes however do not introduce modified approaches that address these differences. Possible implications of the exclusion of plinth masonry and large portions of seismic weight need further assessment and validation, for which different (possibly more sophisticated) concepts must be considered, such as the equivalent frame method or distributed mass system. Since Nepal allows stone masonry in areas with higher seismic hazard levels >0.40 g (opposed to India <0.12 and China <0.15 g), their code is taken as the reference and starting point for follow-up research, which aims to verify the seismic demand by performing seismic capacity checks of the masonry piers and spandrels. The paper ends with an appeal for global collaboration under the research project SMARTnet.

scholarly journals Fragility curves for Italian URM buildings based on a hybrid method

2021 ◽  
Author(s):  
A. Sandoli ◽  
G. P. Lignola ◽  
B. Calderoni ◽  
A. Prota
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Building Stock ◽  
Ground Acceleration ◽  
Damage Scenario

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.

scholarly journals Fragility Curves for Italian Urm Buildings Based on a Hybrid Method

2021 ◽  
Author(s):  
Antonio Sandoli ◽  
Gian Piero Lignola ◽  
Bruno Calderoni ◽  
Andrea Prota
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Building Stock ◽  
Ground Acceleration ◽  
Damage Scenario

Abstract A 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 (IM) to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minim value of PGAs defined for each buildings class.To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber (MCS) 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.

scholarly journals Service Life Prediction of Precast Concrete Structures Exposed to Chloride Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Dawei Zhang ◽  
Yu Zeng ◽  
Mingshan Fang ◽  
Weiliang Jin
Keyword(s):  
Shear Failure ◽  
Precast Concrete ◽  
Probability Model ◽  
Limit State ◽  
Concrete Structures ◽  
Seismic Load ◽  
Ultimate Limit State ◽  
Interface Shear ◽  
Serviceability Limit State ◽  
Corrosion Initiation

Chloride-induced corrosion is widely accepted as one of the primary causes of premature deterioration for concrete structures in marine or deicing salt environment. For precast concrete (PC) structures, such durability problems may even be severer because defects in joint areas, e.g., cracks caused by grout shrinkage and improper construction, can accelerate chloride ion transportation process and may cause the interface shear failure when subjected to seismic load. By applying the path probability model (PPM) and reliability theory, a probabilistic framework was proposed to predict three limit states of PC structures, including corrosion initiation, serviceability limit state, and ultimate limit state. Using Monte Carlo simulation, a beam-to-column joint was further analyzed to illustrate the differences between PC structures and those cast in situ. The analysis indicates that corrosion initiation and serviceability limit state are sensitive to chloride diffusivity at connection area, and the higher pitting factor can significantly influence the bearing capacities of PC structures.

Seismic Reliability of a Fixed Offshore Platform Against Collapse

2014 ◽  
Author(s):  
Mojtaba Dyanati ◽  
Qindan Huang
Keyword(s):  
Seismic Performance ◽  
Limit State ◽  
Shear Capacity ◽  
Offshore Platform ◽  
Ultimate Limit State ◽  
State Function ◽  
Base Shear ◽  
Offshore Structure ◽  
Seismic Reliability ◽  
Fixed Offshore Platform

As many jacket type steel platforms have been constructed in the highly active seismic area, seismic reliability evaluation of such structures is desirable. Ultimate limit state (ULS) with base shear capacity and demand can be used to estimate seismic performance of fixed offshore platform against collapse. Base shear capacity is evaluated from pushover analysis on a 3D finite element model of the offshore structure using different load patterns. Base shear demand is calculated from spectral acceleration at a given site and the total mass of the platform. Uncertainties are considered in both capacity and demand evaluations. With the limit state function, seismic fragility of a prototype structure is assessed using reliability analysis. The results indicate that various load patterns affect the seismic performance evaluation. It is also found that the steel yield stress is a critical parameter in the reliability of the steel jacket platforms.

Seismic Performance of Stone Masonry Buildings Used in the Himalayan Belt

2013 ◽  
Vol 29 (4) ◽  
pp. 1159-1181 ◽  
Author(s):  
Qaisar Ali ◽  
Akhtar Naeem Khan ◽  
Mohammad Ashraf ◽  
Awais Ahmed ◽  
Bashir Alam ◽  
...  
Keyword(s):  
Seismic Performance ◽  
Cost Effective ◽  
Stone Masonry ◽  
Shake Table ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Limit States ◽  
Shake Table Tests ◽  
Capacity Curves ◽  
Rubble Stone Masonry

Rubble-stone masonry structures are found abundantly in the Asian countries along the Himalayan range. Such structures are usually constructed in dry-stone masonry or are constructed in mud mortar, which makes them susceptible to damage and collapse in earthquakes. In order to study the seismic behavior of these structures, dynamic shake table tests on three reduced-scale rubble-stone masonry models were conducted. The models comprised a representative school building, a residential building, and a model incorporating simple cost-effective features in the form of horizontal and vertical reinforced concrete elements. This paper presents the results of shake table tests carried out on rubble-stone masonry buildings including: damage pattern, capacity curves, damage limit states, and response modification factors of these structures. Test data indicates that seismic performance of rubble-stone masonry structures can be significantly improved by incorporating cost-effective features such as vertical members and relatively thin horizontal bands.

scholarly journals A comparative study on a complex URM building: part I—sensitivity of the seismic response to different modelling options in the equivalent frame models

2021 ◽  
Author(s):  
Daria Ottonelli ◽  
Carlo Filippo Manzini ◽  
Corrado Marano ◽  
Emilia Angela Cordasco ◽  
Serena Cattari
Keyword(s):  
Seismic Response ◽  
Dynamic Properties ◽  
Limit State ◽  
Central Italy ◽  
Structural Safety ◽  
Stone Masonry ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Maximum Acceleration ◽  
Equivalent Frame

AbstractThe paper presents the comparison of the results of nonlinear static analyses carried out using six software packages (SWs) available at professional level and operating in the field of the equivalent frame (EF) approach on a model representative of a complex masonry building. The structure is inspired by the school “P. Capuzi” in Visso (MC, Italy), proposed as one of the benchmark structures in the “URM nonlinear modelling—Benchmark project” funded by the Italian Department of Civil Protection within the context of the ReLUIS projects. The 2-stories building is characterized by an irregular T-shaped plan and load-bearing walls consisting of two-leaf stone masonry with a rather regular bond scheme. The school was severely damaged by the seismic sequence that hit Central Italy in 2016/2017 and essentially exhibited a global in-plane box-type response, with a clear evidence of cracks concentrated in piers and spandrels. The availability of an accurate survey of the crack extension represents a precious and rare reference to firstly address in the paper the rules to be adopted in the EF models for the definition of the structural elements geometry. Then, the comparison of results is made with a twofold aim: firstly, by setting the models adopting shared and consistent modelling assumptions across the SWs; secondly, by investigating the sensitivity of the seismic response to some common epistemic and modelling uncertainties (namely: the adoption of various EF idealization rules for walls, the out-of-plane contribution of piers, the flange effect). In both cases, results are post-processed to define reference values of the achievable dispersion. The comparison is carried out in relation to a wide set of parameters, namely: global parameters (e.g. dynamic properties, pushover curves and equivalent bilinear curves); synthetic parameters of the structural safety (i.e. the maximum acceleration compatible with the ultimate limit state); the damage pattern simulated by SWs.

scholarly journals Evaluating the Behaviour Factor of Medium Ductile SMRF Structures

2017 ◽  
Author(s):  
Djamal Yahmi ◽  
Taïeb Branci ◽  
Abdelhamid Bouchaïr ◽  
Eric Fournely
Keyword(s):  
Limit State ◽  
Pushover Analysis ◽  
Design Procedure ◽  
Ultimate Limit State ◽  
Eurocode 8 ◽  
Q Factor ◽  
Local Response ◽  
Base Shear ◽  
Behaviour Factor ◽  
Steel Moment Resisting Frames

In seismic codes, the capacity of structures is calculated using capacity design procedure based on the concept of base shear. The critical parameter in this procedure is the behaviour factor (q-factor), which allows designing the structures at the ultimate limit state accounting for their ductility and reserve strength. In this paper, the q-factor is evaluated for medium ductile steel moment-resisting frames (SMRF) using pushover analysis. The influence of specific parameters, such as the stories number, the “Column/Beam” capacity and the local response of structural members, is studied. The results show that the most important parameter that affects the q-factor is the local response of first-storey columns, while the “Column/Beam” capacity has a less effect on this factor. Furthermore, it is observed that the q-factor value assigned to the studied frames in Eurocode-8 is systematically underestimated for low-rise frame, while the use of this value for high-rise frame is potentially unsafe.

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