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33 pages, 13438 KiB

Open AccessArticle

Investigating the Reliability of Nonlinear Static Procedures for the Seismic Assessment of Existing Masonry Buildings

by Sofia Giusto, Serena Cattari and Sergio Lagomarsino

Appl. Sci. 2024, 14(3), 1130; https://doi.org/10.3390/app14031130 - 29 Jan 2024

Viewed by 850

This paper presents, firstly, an overview of the nonlinear static procedures (NSPs) given in different codes and research studies available in the literature, followed by the results achieved by the authors to evaluate the reliability of the safety level that they guarantee. The [...] Read more.

This paper presents, firstly, an overview of the nonlinear static procedures (NSPs) given in different codes and research studies available in the literature, followed by the results achieved by the authors to evaluate the reliability of the safety level that they guarantee. The latter is estimated by adopting the fragility curve concept. In particular, 125 models of a masonry building case study are generated through a Monte Carlo process to obtain numerical fragility curves by applying various NSPs. More specifically, among the NSPs, the N2 method (based on the use of inelastic response spectra) with different alternatives and the capacity spectrum method (CSM)—based on the use of overdamped response spectra—are investigated. As a reference solution to estimate the reliability of the nonlinear static approach, nonlinear dynamic analyses (NLDAs) are carried out using the cloud method and a set of 125 accelerograms; the results are post-processed to derive fragility curves under the assumption of a lognormal distribution. The focus of this investigation is to quantify the influence that the NSP method’s choices imply, such as the criteria adopted to calculate the displacement demand of a structure or those for the bilinearization of the pushover curve. The results show that the N2 methods are all non-conservative. The only method that provides a good approximation of the capacity of the analyzed URM structures as derived from NLDAs is the CSM. In particular, bilinearization is proven to have a relevant impact on the results when using the N2 method to calculate displacement capacities, whereas the CSM method is not affected at all by such an assumption. The results obtained may have a significant impact on engineering practice and in outlining future directions regarding the methods to be recommended in codes. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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15 pages, 6068 KiB

Open AccessArticle

Experimental Study on the Mechanical Properties of Vertical Corrugated Pipe Grout Anchor Connection Joints

by Fenglin Liu, Hui Qian, Zhizeng Zhang and Haidong Zhang

Appl. Sci. 2023, 13(21), 11889; https://doi.org/10.3390/app132111889 - 30 Oct 2023

Viewed by 777

Abstract

Prefabricated buildings’ quality, safety, and construction efficiency are closely related to the connections between various prefabricated components. This study optimizes the design of corrugated pipe-restrained grout anchor lap connections, further simplifying the construction methodology while ensuring reliable connection performance. The objective is to [...] Read more.

Prefabricated buildings’ quality, safety, and construction efficiency are closely related to the connections between various prefabricated components. This study optimizes the design of corrugated pipe-restrained grout anchor lap connections, further simplifying the construction methodology while ensuring reliable connection performance. The objective is to achieve cost savings and accelerate construction progress. A pull-out test of this new type of joint is conducted, generating two sets of 17 specimens each. The research examines the effects of grouting material strength, grout anchor steel bar anchorage length, and U-shaped stirrup spacing on the connection performance of corrugated pipe grout anchor connections. The results indicated that the specimens primarily experience two types of failure: anchorage failure with steel bar pull-out and steel bar tensile failure without anchorage failure. The strength of the grouting material and the anchorage length of the grout anchor steel bar positively correlate with bond anchorage performance. U-shaped stirrups contribute to restraint and enhance the bonding force between the corrugated pipe, grouting materials, and the grout anchor steel bar to a certain extent. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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16 pages, 7655 KiB

Open AccessArticle

Theoretical Method to Predict Internal Force of Crossbeam in Steel–Concrete Composite Twin I-Girder Bridge under Torsional Loading

by Jiangjiang Li, Yongjian Liu, Liang Chai, Zihan Xing, Bowen Feng and Lei Jiang

Appl. Sci. 2023, 13(11), 6669; https://doi.org/10.3390/app13116669 - 30 May 2023

Viewed by 1225

Abstract

During the operational phase of a bridge, the crossbeam, acting as a supporting member, plays an important role in keeping the cross-sectional shape constant in addition to resisting against various lateral and longitudinal loads and distributing the dead and the live loads to [...] Read more.

During the operational phase of a bridge, the crossbeam, acting as a supporting member, plays an important role in keeping the cross-sectional shape constant in addition to resisting against various lateral and longitudinal loads and distributing the dead and the live loads to the adjacent main girders. The complex functional requirements lead to a complex internal force composition of the crossbeam. When subjected to torque, the two main beams of the twin I-girder bridge will have deformation in opposite longitudinal directions (known as warping deformation) to counteract the torque. The existing research has not considered the impact of main beam warping deformation on the internal force of the crossbeam. Based on the existing research, this article further considers the impact of main beam warping deformation on the internal force of the crossbeam, making the calculation of the internal force of the crossbeam more accurate. The results show that the torsional characteristics of the continuous twin I-girder bridge can be calculated using Vlasov’s theory of thin-walled structures combined with the displacement method. As for the effect of the crossbeam on the torsional stiffness of the structure, it can be managed by making the crossbeam stiffness continuous; however, in general, the equivalent stiffness is small compared to the stiffness of the main beam and it can be ignored. The crossbeam can be simplified to a bar with two solid ends for the internal force calculation whose formula is proposed in this paper, based on the existing frame model, and it can further consider the influence of warping deformation of the main beam on the internal force of the beam, and the calculation accuracy is high. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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21 pages, 9049 KiB

Open AccessArticle

Analysis of the Bearing Capacity of Reinforced Concrete Dapped-End Beams

by Vilius Masėnas, Adas Meškėnas and Juozas Valivonis

Appl. Sci. 2023, 13(9), 5228; https://doi.org/10.3390/app13095228 - 22 Apr 2023

Cited by 3 | Viewed by 2019

Abstract

The dapped-end beam is a widely utilized structural component that offers many benefits in real-world applications. However, abrupt changes in the geometry result in complex stress flows, rendering conventional calculation methods unreliable. The estimation of the bearing capacity becomes particularly challenging when such [...] Read more.

The dapped-end beam is a widely utilized structural component that offers many benefits in real-world applications. However, abrupt changes in the geometry result in complex stress flows, rendering conventional calculation methods unreliable. The estimation of the bearing capacity becomes particularly challenging when such elements are designed with prestressed reinforcement. Previous studies have identified that prestressing can have a negative impact on the behavior of dapped-end beams in specific configurations; however, this effect remains inadequately studied. This study employed both analytical and numerical parametric analyses to compare the behavior of prestressed and non-prestressed dapped-end beams. The results show that prestressing has a significant impact on the crack formation and bearing capacity of dapped-end beams. The intensity of this effect is dependent on various parameters, including shear reinforcement, concrete strength, height of the dap, and the distance between the support and the re-entrant corner. A reduction of approximately 50% in the cracking load was observed when the compressive stress ratio fell within the 0.20–0.25 range. At elevated prestressing levels, cracks emerged in the re-entrant corner prior to the beam being subjected to an external load. The analysis conducted revealed a decline of up to 8.81% in load-bearing capacity attributable to prestressing. The study highlights the importance of assessing reductions in bearing capacity and proposes an analytical calculation model for evaluating such reductions. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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22 pages, 5921 KiB

Open AccessArticle

Seismic Benefits from Coupling Frame Structures with a Hysteretic Mass Damper Inerter

by Angelo Di Egidio and Alessandro Contento

Appl. Sci. 2023, 13(8), 5017; https://doi.org/10.3390/app13085017 - 17 Apr 2023

Cited by 1 | Viewed by 816

Abstract

The coupling of frame structures with external oscillating bodies, such as rigid walls, dynamic mass absorbers, elastoplastic dampers, or tuned mass dampers, can be effective in reducing the displacements of the structure and protecting it against seismic loads. This paper proposes connecting an [...] Read more.

The coupling of frame structures with external oscillating bodies, such as rigid walls, dynamic mass absorbers, elastoplastic dampers, or tuned mass dampers, can be effective in reducing the displacements of the structure and protecting it against seismic loads. This paper proposes connecting an external oscillating body to the first story of a frame structure and studying the effectiveness of the coupling by evaluating the reduction in the displacements of the frame structure. The inertial effects of the oscillating body are increased by introducing a virtual mass, provided by an inerter device. The oscillating body, characterized by physical and virtual masses, is connected to the frame structure through a hysteretic device. The study is performed on a dynamically equivalent three-degree-of-freedom (3-DOF) model, whose equations are written using a direct approach. To verify the effectiveness of the protection device, named hysteretic mass damper inerter (HMDI), in reducing the displacements of the frame structure, the displacement of the first story and the drifts of the upper stories are compared to those of the frame structure not connected to the external oscillating body. An initial spectral analysis, performed on the linearized mechanical system, clarifies the role of the parameters of the external device in the dynamic behavior of the coupled system. An additional seismic analysis is performed by using three single earthquake records first, and then a set of seven additional earthquake records selected to be compatible with the design spectrum of Los Angeles. Specific spectral gain maps are used to organize the results of an extensive parametric analysis. They show that the HMDI reduces both displacements and drifts of the structure in large ranges of the parameters that characterize the HMDI. It is found that the proposed protection method is particularly effective for low- and medium-rise frame structures. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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16 pages, 4190 KiB

Open AccessArticle

Influence of Pile Foundation Stiffness on Column Design in One-Story Reinforced Concrete Frames

by Ireneusz Dyka and Krzysztof Klempka

Appl. Sci. 2023, 13(5), 2915; https://doi.org/10.3390/app13052915 - 24 Feb 2023

Viewed by 1868

Abstract

When designing reinforced slender columns for the lowest story of buildings, all factors that may affect the load-bearing capacity should be considered. One is the increase in the bending moment value caused by the rotation of the supporting foundation. The geotechnical parameters of [...] Read more.

When designing reinforced slender columns for the lowest story of buildings, all factors that may affect the load-bearing capacity should be considered. One is the increase in the bending moment value caused by the rotation of the supporting foundation. The geotechnical parameters of subsoil stiffness and the method of calculating foundation displacements are the main influences. This problem applies to both shallow foundations and pile foundations. The article presents this issue in relation to pile foundations in multilayered subsoils and also the method and examples of second-order calculations that take into account the influence of pile support and columns’ nominal stiffness. The results showed that taking into account the stiffness of the pile foundation has an impact on the increase in bending moments in the columns, and this cannot be ignored in the design. The presented method allows for a precise, safe and optimal design of concrete columns supported by foundations on multilayered subsoils. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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17 pages, 4769 KiB

Open AccessArticle

Band Gap Analysis for Materials with Cookie-Shaped Auxetic Microstructures, Using Finite Elements

by Dimitrios Chinis and Georgios E. Stavroulakis

Appl. Sci. 2023, 13(5), 2774; https://doi.org/10.3390/app13052774 - 21 Feb 2023

Cited by 3 | Viewed by 1302

Abstract

Microstructures, including auxetic ones, influence the overall behavior of a material. Particularly during wave propagation, band gaps may appear. This study focuses on the discovery and analysis of the band gaps that occur in a material with auxetic microstructures of the cookie type, [...] Read more.

Microstructures, including auxetic ones, influence the overall behavior of a material. Particularly during wave propagation, band gaps may appear. This study focuses on the discovery and analysis of the band gaps that occur in a material with auxetic microstructures of the cookie type, which have certain advantages with respect to production and fatigue resistance. Finite element analysis at a representative volume element, using Bloch theory, and verification with a plate made of microstructures at various assemblages has been used. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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16 pages, 1813 KiB

Open AccessArticle

Decision-Making Based on Multi-Dimensional Quality Control for Bridges

by Seyed Mohammad Sadegh Lajevardi, Paulo B. Lourenço, Hélder S. Sousa and José C. Matos

Appl. Sci. 2023, 13(2), 898; https://doi.org/10.3390/app13020898 - 9 Jan 2023

Cited by 1 | Viewed by 1404

Abstract

Quality control (QC) may be applied as a framework for maintenance planning when assigning different intervention measures to single structural elements or systems. This work proposes a reliability-based maintenance decision-making process for planning visual inspections on bridges based on the value of information [...] Read more.

Quality control (QC) may be applied as a framework for maintenance planning when assigning different intervention measures to single structural elements or systems. This work proposes a reliability-based maintenance decision-making process for planning visual inspections on bridges based on the value of information and prior inspection data, and also promotes updating and improvement cycles for subsequent planning. To that aim, an integration between SHM (Structural Health Monitoring) data with a multidisciplinary approach is proposed to obtain a reliability index attending to QC. The data analysis was mainly carried out with respect to an existing measurement database and structural assessments, which were combined to obtain weighted importance coefficients for each component according to their significance in the structure. The Iranian railway network has a built stock of nearly 28,200 bridges from which a database obtained from 104 bridges was studied in this work, considering the data obtained from technical identification checklists. The results were then calibrated and validated with a dataset of seven bridges, which were inspected onsite. The inspection comprised the identification and grading of damages and defects on each element. Observed defects were considered as input for the risk analysis of each component of the network by considering the probability of detection, occurrence and its likely consequences. Decision making with inspection and intervention costs optimization was then performed, for a specific case study, using Principal Component Analysis (PCA) together with the value of information (VOI) for data filtering. With this approach, several parameters with lower values reduced from inspection and other valuable data remain for bridge quality assessment with optimum maintenance cost. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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21 pages, 4930 KiB

Open AccessArticle

Infill Variability and Modelling Uncertainty Implications on the Seismic Loss Assessment of an Existing RC Italian School Building

by Gianrocco Mucedero, Daniele Perrone and Ricardo Monteiro

Appl. Sci. 2022, 12(23), 12002; https://doi.org/10.3390/app122312002 - 24 Nov 2022

Cited by 2 | Viewed by 1123

Abstract

Past earthquake evidence has shown the high vulnerability of Italian school buildings, given by the extensive damage observed to structural and non-structural elements. Such vulnerability demonstrates the need to undertake a seismic risk assessment and reduction strategies for critical facilities and allocation of [...] Read more.

Past earthquake evidence has shown the high vulnerability of Italian school buildings, given by the extensive damage observed to structural and non-structural elements. Such vulnerability demonstrates the need to undertake a seismic risk assessment and reduction strategies for critical facilities and allocation of national funds for retrofit interventions to those regions where seismic risk is higher. To do so, Expected Annual Losses (EAL) are evermore considered one of the main seismic risk metrics, which can, however, be largely affected by the epistemic uncertainty that typically characterizes the material and geometrical properties of existing buildings, particularly masonry-infilled reinforced concrete (RC) ones. This paper investigates the implications of accounting for a thorough identification of sources and characterization of uncertainty in seismic loss estimates on the risk assessment of a typical Italian masonry-infilled RC school building. The variability in masonry infill properties and modeling assumptions, as well as the subsequent epistemic uncertainty, are explicitly considered in the loss estimation of the RC school building. Specifically, the impact on the expected annual loss ratio is quantified in terms of both structural and non-structural components, depending on the engineering demand parameter to which they are sensitive. The results show that, when considering the uncertainty related to the variability in masonry infills, higher loss ratios of up to 30% are obtained with respect to the available literature estimates. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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21 pages, 6666 KiB

Open AccessArticle

Axial Compression Behavior of Steel Angle-Corrugated Steel Plate-Confined Concrete Columns

by Zexuan Sun, Yun Zou, Chengquan Wang, Jie Pan and Li Wang

Appl. Sci. 2022, 12(21), 10819; https://doi.org/10.3390/app122110819 - 25 Oct 2022

Cited by 2 | Viewed by 1744

Abstract

This paper proposes a novel type of steel angle-corrugated steel plate-confined concrete column (SA-CS column). The axial compression behavior of the SA-CS column was investigated by load experiments and finite element (FE) simulation. The study also compared the load–displacement curves, core concrete strength [...] Read more.

This paper proposes a novel type of steel angle-corrugated steel plate-confined concrete column (SA-CS column). The axial compression behavior of the SA-CS column was investigated by load experiments and finite element (FE) simulation. The study also compared the load–displacement curves, core concrete strength index, and specimens’ ductility indices between the SA-CS columns and concrete-filled steel tube (CFST) columns. The results indicated that the mechanical properties of the SA-CS column were better than those of the CFST column with a similar steel ratio. The rationality and reliability of the finite element model were confirmed by comparing the experimental results’ load–displacement curves and failure modes. Based on the FE model, a supplementary parametric analysis of the effects of the compressive strength of core concrete, thickness, yield strength, and wave height of the corrugated steel plate, thickness, and yield strength of the steel angles was conducted. Moreover, some existing design codes were assessed based on the numerical results available in this study. A new calculating model for the SA-CS column was proposed, which is capable of reasonably predicting the numerical results. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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20 pages, 4105 KiB

Open AccessArticle

Unified Simplified Capacity Model for Beam-Column Joints into RC Moment Resisting Frame

by Giancarlo Ramaglia, Gian Piero Lignola, Francesco Fabbrocino and Andrea Prota

Appl. Sci. 2022, 12(21), 10709; https://doi.org/10.3390/app122110709 - 22 Oct 2022

Cited by 1 | Viewed by 1211

Abstract

Seismic vulnerability of reinforced concrete (RC) buildings is strongly influenced by beam-column joints. Horizontal and vertical structural members converge in beam-column joints, as extremely delimited areas where the internal forces in concrete core and reinforcing bars have elevated stress gradients. In order to [...] Read more.

Seismic vulnerability of reinforced concrete (RC) buildings is strongly influenced by beam-column joints. Horizontal and vertical structural members converge in beam-column joints, as extremely delimited areas where the internal forces in concrete core and reinforcing bars have elevated stress gradients. In order to fully understand the seismic behavior of RC buildings and the related failures of T- and X-shaped beam-column joints (external corner and internal-positioned), an analytical model of RC joint behavior is proposed in a unified and simplified way. The equilibrium equations of cracked joint portions allow the assessment of internal stresses’ evolution at increasing values of column shear forces. In this way, the strength hierarchy is evaluated in terms of capacity for the different potential failure modes. This can drive, as a useful tool for designers, the design of new efficient structures or the assessment of existing ones to occur, with subsequent interventions to move an initial undesired failure mode to a more suitable one. Nearly 500 experimental results of tests available in the literature are compared with the analytical predictions of the proposed model. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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19 pages, 13324 KiB

Open AccessArticle

Elasto-Plastic Short Exoskeleton to Improve the Dynamic and Seismic Performance of Frame Structures

by Angelo Di Egidio, Stefano Pagliaro and Alessandro Contento

Appl. Sci. 2022, 12(20), 10398; https://doi.org/10.3390/app122010398 - 15 Oct 2022

Cited by 2 | Viewed by 1372

Abstract

The coupling with external mechanical systems such as oscillating masses working as tuned mass dampers, dynamic mass absorbers, elasto-plastic dampers, and rigid walls is an effective method to reduce the displacements and drifts of structures under external loads. An alternative method is provided [...] Read more.

The coupling with external mechanical systems such as oscillating masses working as tuned mass dampers, dynamic mass absorbers, elasto-plastic dampers, and rigid walls is an effective method to reduce the displacements and drifts of structures under external loads. An alternative method is provided by the coupling of the structure with an independent, auxiliary elasto-plastic system. This paper investigates the dynamic and seismic behaviour of a structure rigidly coupled with an auxiliary yielding mechanical system under harmonic and seismic ground excitation. A two-degree-of-freedom model is used to describe the dynamic and seismic behaviour of the main structure rigidly coupled to the yielding system, which is described by a one-degree-of-freedom model. The auxiliary system has an elasto-plastic constitutive behaviour that is modelled by a Bouc-Wen model. The equations of motion of the coupled system are obtained by a direct approach. The coupling with the yielding system is considered beneficial if the displacements of the coupled system reduce with respect to those of the stand-alone frame structure. An extensive parametric analysis is performed to point out the role of the mechanical parameters that describe the elasto-plastic constitutive behaviour of the auxiliary system. Results reveal that in large ranges of the parameters’ values, the coupling with the elasto-plastic system improves the performance of the frame structure. Full article

(This article belongs to the Special Issue Structural Design and Analysis for Constructions and Buildings)

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