Structures最新文献

{"title":"Evaluation of lateral strength capacity of cored interlocking block masonry piers under variable pre-compression loads","authors":"Syed Mehran Yousaf,&nbsp;Akhtar Gul,&nbsp;Khan Shahzada,&nbsp;Sajjad Wali Khan","doi":"10.1016/j.istruc.2024.107640","DOIUrl":"10.1016/j.istruc.2024.107640","url":null,"abstract":"<div><div>The lateral strength of Cored Interlocking Block Masonry (CIBM) depends on the activation of frictional forces at the interfaces of the bed joints, which is influenced by the axial compression load on the walls. An experimental attempt is made in this paper to assess the influence of precompression axial load on CIBM piers through quasi-static testing procedure. For this purpose, a total of nine (9) CIBM piers were tested experimentally under variable pre-compression loads. The nine CIBM piers were divided into three categories based on variable precompression loading, corresponding to the load of single to three-story buildings. The assessment of structural behavior of CIBM includes damage patterns, lateral strength and stiffness, ultimate story drift, energy dissipation and dampness characteristics. Test results show a substantial enhancement in the lateral load carrying capacity up to 66.58 % by comparing with the lower value of pre-compression load. Compared to low precompression loads, the CIBM piers behaved in a more stable manner at high precompression loading.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107640"},"PeriodicalIF":3.9,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimised rotational-spring component-based modelling strategy for seismic resistant steel-concrete composite joints and frames with continuous or isolated slab","authors":"Marco Fasan ,&nbsp;Chiara Bedon ,&nbsp;Maria Rosaria Pecce","doi":"10.1016/j.istruc.2024.107689","DOIUrl":"10.1016/j.istruc.2024.107689","url":null,"abstract":"<div><div>Joints and frames in steel-concrete composite systems represent complex mechanical assemblies that require specific calculation procedures to optimise their detailing and structural capacity, particularly under seismic loads. To this aim, component-based modelling approaches should be able to account for the most relevant mechanisms and resistance/stiffness behaviours of individual members, and their mutual interaction. In this paper, two different simplified non-linear approaches are considered for steel-concrete composite beam-to-column joints, and are specifically applied to a seismic resistant case-study frame with X-concentric bracings. Both beam-to-column joints with or continuous (“JA” joint) or fully isolated (“JB” joint) slab are examined. First, non-linear axial springs are assembled and calibrated on the base of a previous study (“Type 1″ model (“T1″)), according to force-displacement relationships proposed in the DPC-ReLUIS Italian guidelines. Successively, a novel modelling approach based on non-linear rotational springs is presented (“Type 2″ model (“T2″)), to further simplify the computational cost of T1 strategy, and allow to efficiently account for the moment-rotation behaviour of the examined joints. The preliminary numerical validation is carried out based on past literature experiments. Moreover, the optimized T2 approach is used to explore the in-plane lateral, seismic performance of a 2D steel-concrete composite frame, which is specifically designed with X-concentric bracings. The seismic capacity of the frame (and the associated interaction of components, especially the joint zone with the bracing system) is addressed on the base of pushover analyses.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107689"},"PeriodicalIF":3.9,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interaction between material and process parameters during 3D concrete extrusion process","authors":"Ali Fasihi,&nbsp;Nicolas A. Libre","doi":"10.1016/j.istruc.2024.107678","DOIUrl":"10.1016/j.istruc.2024.107678","url":null,"abstract":"<div><div>Extrusion of cement-based materials in additive manufacturing is influenced by a complex interaction of various material and process parameters. This study aims to investigate the impact of rheological properties and printing parameters on the extrudability of cement-based materials as well as the interaction between rheological properties of print materials and extrusion speed, as a key printing process parameter. 20 different print materials with diverse rheological properties were extruded at 10 different extrusion speeds. The effect of material parameters (i.e. rheological properties) and process parameters (i.e., extrusion speed) and their interaction during the extrusion process were evaluated using filament continuity, conformity and consistency. At a constant printing speed, a higher yield stress adversely impacted filament continuity in mixtures with a yield stress of over 260 Pa, whereas viscosity showed minimal influence on filament quality within the tested range of the rheological properties. The results of this study highlighted a significant correlation between material and process parameters and that adapting process parameters to variations in material properties is crucial for meeting printing criteria. The filament consistency of the mixtures with high yield stress was more sensitive to change in the extrusion speed than that of mixtures with low yield stress. An opposite trend, however, was observed for filament conformity where low yield stress mixtures showed a higher sensitivity to the extrusion speed. A procedure was suggested and applied to determine the optimum extrusion speed. Optimal extrusion speeds enabled printing mixtures with a broader spectrum of rheological properties with an acceptable visual quality, filament conformity and consistency requirements. With extrusion speed adjustment, the extrudability window was expanded from dynamic yield stress of 108–126 Pa to 108–263 Pa and plastic viscosity of 8.2–12.3 Pa.s to 5.1–16.4 Pa.s.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107678"},"PeriodicalIF":3.9,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accurate equivalent analysis models and performance evaluation of precast concrete shear walls","authors":"Qihao Han ,&nbsp;Dayang Wang ,&nbsp;Junru Li ,&nbsp;Naeem Yasir","doi":"10.1016/j.istruc.2024.107696","DOIUrl":"10.1016/j.istruc.2024.107696","url":null,"abstract":"<div><div>Precast concrete shear walls with horizontal steel connections (PCSWHs) were proposed and experimentally studied. To improve the design and analysis efficiency of the PCSWHs with adequate accuracy and reliability, the constitutive models of the connections joints and precast shear wall modules were established using theoretical derivation, and accurate equivalent analysis (AEA) models of the PCSWHs were developed. Furthermore, performance evaluation of three-story and three-span precast frame-shear wall structures with four types of shear walls, including the CAST model (cast-in-situ shear walls), PRE-H model (PCSWHs were adopted), PRE-HVR model (precast concrete shear walls having “strong horizontal and weak vertical” connections, which abbreviated as PCSWHVs, were adopted, and frame beam was connected), and PRE-HVS model (PCSWHVs were adopted, and frame beam can slide freely), was carried out based on the AEA models. Results show that the interaction between the stud of the steel connector and concrete can be simplified as a four-point skeleton curve. The AEA models of the PCSWHs were validated. PCSWHVs can significantly reduce the shear force in the deep beams around the shear walls, and it effectively avoids the undesirable brittle shear failure of deep beams. Compared with the CAST model, the maximum decrease rate of shear force in the deep beams of the PRE-HVS models is 34.56 %. PCSWHVs can fully utilize the plastic energy dissipation of steel shear keys (SSKs). The SSKs in the PRE-HVR and PRE-HVS models enter a plastic yield state under rare earthquakes, and the latter develops greater hysteretic energy dissipation than the former.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107696"},"PeriodicalIF":3.9,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A test on fire-induced damage of concrete with multiple parameters analysis—Based on tunnel linings of China","authors":"Hongyun Yang,&nbsp;Zihan Wang,&nbsp;Xiang Chen,&nbsp;Zhi Lin,&nbsp;Qiang Li","doi":"10.1016/j.istruc.2024.107664","DOIUrl":"10.1016/j.istruc.2024.107664","url":null,"abstract":"<div><div>Fires in highway tunnels will have a significant impact on the structural performance of lining materials. A ablation test was conducted on 288 concrete specimens (1500 ×1500 ×1500 mm) with four commonly used grades of C20, C25, C30, and C35 at temperature levels of 300 ℃, 600 ℃, 750 ℃, and 900 ℃ for constant periods of 1 h, 2 h, and 4 h. The experiment revealed that: (1) From low to high temperatures, the specimens experienced cracking, spalling, explosion and eventually complete collapse; all grades of concrete remained intact or mostly intact at 600 ℃ but suffered varying degrees of damage above 750 ℃. (2) At the same fire temperature, the damage rate increased linearly with longer ablation time; while at the same ablation time, the damage rate increased quadratically with higher fire temperature. (3) The ultrasonic wave velocity ratio decreased exponentially as the ablation time increased; higher fire temperatures resulted in lower wave velocity ratios within the same ablation time period and there was a turning point at a two-hour ablation time where specimen integrity was lost. (4) For concrete specimens of the same grade and under identical exposure times to fire, as the fire temperature increased,the rate of compressive strength reduction accelerated significantly; sudden drops in compressive strength occurred at temperatures of 600 °C，750 °C，and900°C,and there was a turning point for compressive strength reduction loss after one hour's ablation to fire.(5) When subjected to high ablation temperatures,the decrease rate in concrete strength exceeded that in wave velocity,and changes in strength were more sensitive than changes in wave velocity.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107664"},"PeriodicalIF":3.9,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced data-driven shear strength prediction for RC deep beams: analyzing key influencing factors and model performance","authors":"Yassir M. Abbas,&nbsp;Abdulrahman S. Albidah","doi":"10.1016/j.istruc.2024.107651","DOIUrl":"10.1016/j.istruc.2024.107651","url":null,"abstract":"<div><div>Accurately predicting the shear strength of reinforced concrete (RC) deep beams remains a challenging task due to the complex interplay of influencing factors. This study advances the field by integrating sophisticated machine learning (ML) techniques. A comprehensive dataset of 386 beams was compiled, covering a diverse range of geometries, materials, loading conditions, and reinforcements. Utilizing a random forest (RF) algorithm, a robust ML model was developed that significantly outperforms existing models, including those by Feng et al., in both accuracy and consistency. This model achieved a nearly perfect mean prediction (1.03) and the lowest coefficient of variation (19.4 %) for predicted versus target values. It identifies key parameters (beam width, effective depth, shear span-depth ratio, load and support plate widths, and material properties of concrete and steel) as critical factors influencing shear strength. In addition, an innovative nonlinear model based on insights from the ML model and fundamental mechanical principles was proposed. This nonlinear model, refined using data from 1650 deep beams, surpasses traditional models (e.g., those specified by ACI-318 and Eurocode-2) demonstrating superior predictive accuracy. The study illustrates the successful integration of traditional engineering principles with advanced ML techniques, highlighting the substantial potential of interdisciplinary approaches. These findings offer valuable insights into the complex relationships among material properties, reinforcement types, and shear strength, advancing our understanding and predictive capabilities for RC deep beams.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107651"},"PeriodicalIF":3.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic modeling and substructuring analysis leveraging long short-term memory neural network","authors":"Hong-Wei Li ,&nbsp;Jian Zhou ,&nbsp;Shuo Hao ,&nbsp;Yi-Qing Ni ,&nbsp;Zhao-Dong Xu","doi":"10.1016/j.istruc.2024.107602","DOIUrl":"10.1016/j.istruc.2024.107602","url":null,"abstract":"<div><div>Existing studies that use neural networks for civil engineering problems mostly established neural network models for the entire structure, and seldomly created dynamic interaction between neural network models and other models. This paper focuses on the dynamic substructuring modeling of structures installed with energy dissipation devices (EDDs) that are modeled by long short-term memory neural network (LSTM) models. Numerical studies at the device level show that LSTM models can be effectively trained to represent different physical models of EDDs with high precision. Investigations of different training schemes indicate that using band-limited white noise inputs to generate the training dataset is the optimal option. Procedures to establish coupling models for the inter-story-damped and base-isolated structures in the MATLAB Simulink platform are presented, where the LSTM model of EDDs is coupled with the physical model of the main structure through the state-space substructuring method. Seismic analyses of these two types of structures are conducted, showing that the coupling model achieves high performance and could relax computational or programming requirements that EDDs’ physical models may have. The present work reveals that the proposed hybrid structural modeling procedure utilizing the LSTM model is a flexible and practical option for structural analysis.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107602"},"PeriodicalIF":3.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic performance and failure mechanisms evaluation of multi-story elliptic and mega-elliptic bracing frames: Experimental and numerical investigation","authors":"Habib Ghasemi Jouneghani ,&nbsp;Younes Nouri ,&nbsp;Parham Memarzadeh ,&nbsp;Abbas Haghollahi ,&nbsp;Ehsan Hemati","doi":"10.1016/j.istruc.2024.107658","DOIUrl":"10.1016/j.istruc.2024.107658","url":null,"abstract":"<div><div>In recent decades, researchers have evaluated the seismic performance of the innovative Elliptic-Braced Resisting Frames (ELBRFs) only in single-story single-span configurations. Although numerical studies have investigated the behavior of multi-story ELBRF configurations, the lack of laboratory data has cast doubt on the reliability of these numerical results. To address this gap in knowledge, this article evaluates the seismic performance and failure mechanisms of multi-story ELBRFs through a laboratory program and compares them with a developed type of this bracing system known as Mega Elliptic-Braced Resisting Frames (MELBRF). The key contribution of this research is the provision of laboratory test data for multi-story ELBRF and MELBRF systems, which can be utilized to validate numerical models and investigate their seismic characteristics. In this study, laboratory tests are used to examine the cyclic behavior and to calculate parameters such as strength, ductility, stiffness, energy dissipation, seismic performance, and failure modes in multi-story specimens. To this end, an experimental test of a 1/6 scale single-span four-story ELBRF specimen and a two-span four-story MELBRF specimen under cyclic quasi-static loading was conducted. Next, the seismic behavior of the proposed specimens is compared with other types of bracing systems such as X-, V-, Inverted-V, Two-Story X-, and Two-tiered diagonal braced frames in a story-base model under cyclic quasi-static loading through nonlinear FEM analyses. The results indicated that the yielding of elliptic braces would delay the failure mode of adjacent elliptic columns and thus help tolerate significant nonlinear deformation to the point of ultimate failure. The response modification factor in ELBRF and MELBRF is 7.3 and 6.5, respectively. Symmetrical behavior, high energy absorption, appropriate stiffness, and high ductility in comparison with conventional systems are some of the advantages of the proposed systems.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107658"},"PeriodicalIF":3.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protocol of investigations for the preliminary assessment of the structural safety of highway overpasses","authors":"Pier Paolo Rossi,&nbsp;Nino Spinella","doi":"10.1016/j.istruc.2024.107609","DOIUrl":"10.1016/j.istruc.2024.107609","url":null,"abstract":"<div><div>This paper presents the results of a protocol of investigations that have been carried out on 15 overpasses, located along the highway A18 in Sicily (south of Italy) and built about fifty years ago, with the aim of achieving a preliminary evaluation of the structural safety of these overpasses. The investigated overpasses are characterized by a three-span deck consisting of a reinforced concrete slab and prestressed concrete girders. The girders of the central span are simply supported by two Gerber saddles located on cantilever girders at the two ends of the same span. The safety level of the overpasses is investigated by means of different activities that include visual inspection and computation of the class of attention of the overpasses according to the Italian Bridge Guidelines for the classification and the risk management, safety evaluation and monitoring of existing bridges, laboratory and in situ tests on materials, pachometric, georadar and video-endoscopic tests on structural details, and static load tests of the overpasses. The results of the static load tests have also been used to assess the accuracy of two numerical models of the overpasses. These models are elastic but characterised by different levels of accuracy and computational burden: while the first model is the well-established and simple Courbon-Albenga method, the second is a finite element model characterised by a more refined simulation of the response of slabs, longitudinal girders and crossbeams. The results of the investigations have been critically analysed and discussed to underline the ability of the protocol to reveal possible deficiencies of the overpasses and thus identify overpasses that are liable to structural interventions or more accurate and expensive investigations.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107609"},"PeriodicalIF":3.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance-based seismic design of low-rise steel moment-resisting frames targeting collapse fragility curve","authors":"Mahsa Noruzvand,&nbsp;Mohtasham Mohebbi,&nbsp;Kazem Shakeri","doi":"10.1016/j.istruc.2024.107630","DOIUrl":"10.1016/j.istruc.2024.107630","url":null,"abstract":"<div><div>The aim of this study is to develop a performance-based seismic design method targeting a desirable collapse fragility curve. This direct fragility-based design method is developed and validated for low-rise steel moment-resisting frames. To this end, a relationship is first defined between target fragility curve and design displacement. To this end, 4-story buildings are designed with the design drift ratios of 1.5 % to 4 % and the seismic fragility analysis is performed via the Monte Carlo simulation. The mentioned relationship is derived by plotting the median collapse spectral acceleration versus the design drift ratio. With regard to have this relationship, a modified version of performance-based plastic design method is then proposed. The direct fragility-based design method has been proposed for the low-rise buildings located in Log Angeles. However, its efficiency is also validated for two other regions of Vancouver, Canada and San Francisco, U.S. It can be found from the results that the fragility curve of designed buildings is very close to the target fragility curves. Therefore, the direct fragility-based design method is capable of achieving a target fragility curve and can be considered as an effective design method for low-rise steel moment-resisting frames.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"70 ","pages":"Article 107630"},"PeriodicalIF":3.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}