Structures In Seismic Zones Research Articles

Assessment of RC Frame Structure under Different Seismic Condition

Abstract: Structures in seismic zones are especially prone to collapse during significant ground motion occurrences. This susceptibility is sometimes linked to flaws in seismic design principles, notably in the selection of suitable structural systems. Equivalent static analysis, which is often employed in seismic design, may not accurately account for the structure's strength and stiffness. As a result, ground floor columns may become highly reinforced, thereby lowering ductility, and causing poor performance. This thesis offers a parametric study of an RC frame structure developed for various seismic zones. The finite element software is used to model the structure to investigate performance levels. Pushover analysis was performed to determine the structure's seismic capacity and behavior under various seismic conditions. Parametric research employing RC Frames with demand variation was done to investigate the structure's behavior in different seismicity zones across the country

Concept of combined strain-stress state control of long span structures

Purpose: Argumentation of necessity of special protective system design to protect structures in seismic zones and remote areas from specific loads. Such protective system combines seismic isolation and internal force control systems.Research findings: Restrictions of long-span structures construction are reviewed. Such restrictions are caused by building conditions embodied in National Building Codes and Standards. Combined and separate use of seismic isolation and internal force control systems is a critical specific load protection. Present inventions and experience in the field of seismic isolation and internal force control systems are reviewed.Value: The article determines problems of protective system design based on the control for combined strain-stress state.

Experimental Investigation of High-Force-To-Volume Extrusion Damper Subjected to Cyclic and Time History Loading

Abstract The ability of energy dissipation from earthquake force in a controlled and iterative manner will play a vital role in maintaining structural reliability for various forces. High force-to-volume (HF2V) extrusion damper is a promising technology with simple designs, high damping force and achieving design requirements. This paper develops HF2V extrusion damper with multiple toothing configuration for seismic application. The experimental verification has been undertaken on lead extrusion dampers with various frequency range of 0.5 to 2 Hz. The maximum load-carrying capacity is 10.48 kN with strokes up to 5mm are observed with hysteresis loop with some recentering capability has a stiffness value up to 2*106 N/m, and force levels up to 2-10 kN. The maximum load carrying capacity for time history loading for Northridge earthquake is 11.57 kN. The overall findings suggest that silicone sealant may be employed to build and characterize extrusion dampers with maximum energy dissipation and high force/volume interactions. The suggested device may be a potentially effective way to provide additional energy dissipation to structures in seismic zones, according to the mechanical characteristics to the frequency. Additionally, the system can withstand for earthquake time histories, and ensuring maintenance-free operation even in the midst of frequent ground vibration.

Experimental analysis on the out-of-plane structural performance of single-face superposed shear walls with different horizontal connections

Single-face superposed (SFS) shear wall is a novel precast concrete sandwich panel (PCSP) wall that can be used as load-bearing walls in high-rise buildings and underground structures in seismic zones. This paper investigates the out-of-plane structural performance of SFS shear walls with different horizontal connections. Three SFS shear walls with different lap-spliced rebar connection configurations at the horizontal connections were designed and tested to compare their out-of-plane structural performance with that of a cast-in-place specimen, in terms of failure modes, cracking patterns, load-displacement curves, stiffness degradation curves, ductility, and force transfer mechanism of lap-spliced rebar connections. The test results showed that the SFS shear wall specimens exhibited and maintained a high level of composite action until failure, and the studied three different horizontal connections can allow effective force transfer between the upper shear walls and the lower. The stiffness, ductility, and ultimate bearing capacities of SFS shear walls under out-of-plane monotonic loading were significantly higher than those of cast-in-place shear walls. The bearing capacity was found to depend to a large extent on the location of additional vertical connecting rebar, the displacement mainly caused by rigid body rotation and related to crack width at joint. A calculation method of the ultimate bearing capacity of a SFS shear wall under out-of-plane horizontal loads was proposed. Finally, some suggestions on the setting of the vertical connecting bar are put forward.

MACHINE LEARNING FOR THE DOCUMENTATION, PREDICTION, AND AUGMENTATION OF HERITAGE STRUCTURE DATA

Abstract. The paper presents an effort to develop learning models based on the massive amounts of data that has been accumulated over the past decades during the process of digital documentation of heritage structures around the globe especially those in disaster zones.The development of an ontology is proposed that describes heritage buildings, their sites, and major hazard events that may cause damage to them. This ontology can serve as a repository for documenting heritage structures and provide highly structured data for developing machine learning systems that can identify patterns of damage from recorded image data. For heritage structures in seismic zones, the first step in ontology development is analyzing available earthquake information about the event and the damage information. The resulting model will create links between information items, for example relating the extent of the damage of an element to the earthquake magnitude and its distance from the epicenter. The ontology may also include collected images from previous earthquake events, with links to the objects in each image. Special tools will focus on selecting sub-models to be included in a machine learning model. For example, if the learning objective is to identify the damage and its extent from an image, then the rules will select the features in the model that relate to structural damage and identify each type of damage. It is hoped that this work will help develop learning systems that speed up processing of large volumes of image damage data collected from heritage sites.

Analysis of Steel Buildings with Steel Plate Shear Walls at the Corners with Varying Thickness

Nowadays the construction of steel buildings is very common. When a building's height increases, its stability is taken into account. Shear walls have to be added to these structures for them to endure the lateral loads caused by wind and seismic activity. Steel plate shear walls (SPSW), one of the shear wall types, are the most efficient since they are lighter and thinner, enhancing the architectural space and rigidity of the structures. This study employs ETABS software to display the seismic analysis of a 15-story steel structure in seismic zone III that has steel plate shear walls at the corners and centre. This article also compares the performance of another 15-story steel building with steel plate shear walls of different thicknesses (15mm, 20mm, and 25mm). The steel building with the thicker steel plate shear walls at the corners performs better in terms of storey displacement and storey drift when compared to other structures. According to IS 1893:2016, the models are examined using the response spectrum method.

Seismic performance of precast concrete walls with grouted sleeve connections using large-diameter bars

This paper proposes an innovative assembly technique using large-diameter bars anchored in several single-row, widely spaced grouted sleeves at the keyway-type horizontal joint to realize an indirect vertical connection between adjacent precast concrete (PC) walls, which has the advantages of high efficiency and ease of construction. To examine the effect of vertical connection strength (rebars' diameter at horizontal joints) on the seismic performance of PC shear walls, quasi-static cyclic loading tests on five full-size wall specimens, including one cast-in-place specimen and four PC specimens with grouted sleeve connections, are carried out. Seismic performance indicators in terms of failure modes, hysteresis characteristics, energy dissipation, ductility, and stiffness degradation of PC walls are investigated and compared with those of the cast-in-situ wall. Meanwhile, the method for predicting the bearing capacity of PC walls with large-diameter rebars is developed. The results show that the failure modes of cast-in-situ and precast walls are controlled by bending instead of shear, but there is an obvious difference in the crack propagation between the two types of walls. Carrying capacity, ductility factor, stiffness, and energy dissipation of PC walls are significantly enhanced by increasing the connection strength, by 44.1%, 23.9%, 72.1%, and 24.0%, respectively, when the connection strength reaches around 90%. Particularly, the PC wall's seismic performance is comparable to that of the cast-in-situ wall when the connection strength is 90%. The calculated results are well-matched with the experimental results, the proposed calculation method reliably predicts the bearing capacity of PC walls with large-diameter rebars. The assembly technique can be safely applied to multi-story PC wall panel structures in seismic zones.

Self-Centering Structures Against Earthquakes: A Critical Review

ABSTRACT With critical lessons drawn from past major earthquakes, the engineering community is appealing for a fundamental shift in the existing design philosophy for structures in seismic zones. One strategy is to endow structures with self-centering (SC) capability. While the concept of SC structures is not new, many novel technologies have been recently emerging that are more efficient, compact, and cost-effective; on the other hand, growing controversy and dispute have also been appearing with deepening investigations. This paper presents a critical review of the evolution of SC technologies and systems for both researchers and practitioners, with an emphasis on post-tension (PT), high-performance spring, and shape memory alloy (SMA) strategies. These SC technologies, together with various energy dissipation options, form the basis of a large part of the newly proposed SC philosophies. This review also includes typical SC structural members such as beam-to-column connections, braces, dampers, shear walls, bridge piers, and isolation bearings, followed by a discussion on the dynamic behavior from a system-level point of view. Available design approaches for SC structures are also touched upon, and practical applications that have emerged over the past decades in several countries including Canada, China, New Zealand, and the US are presented. This paper concludes with an executive summary that covers technological advances, knowledge gaps, and future research directions.

Evaluation of hybrid NSM-CFRP technical bars and FRP sheets for seismic rehabilitation of a concrete bridge pier

Seismic retrofit is a cost-effective and sustainable solution for improving bridge structures in seismic zones. Fiber Reinforced Polymer (FRP) is commonly used to replace steel components in retrofit projects due to their light weight, high strength, and high corrosion resistance. The fabrication of novel hybrid structures from FRP and concrete is the next step researchers are addressing. In this context, the present study focuses on numerical modeling of the experimentally determined response of a hybrid FRP and concrete bridge pier subjected to quasi-static tests. The results from FEM showed strong agreement with the experimental response in terms of load-displacement curve and failure mode. After validating the model, alternative designs (changing the height of the CFRP slab, changing the height and compaction of the CFRP bar, and concrete encasement with and without CFRP slab) were numerically tested to investigate the effects of each model on the load capacity. With the conventional concrete encasement, the bearing capacity of the bridge pier can be rehabilitated, but with the CFRP plate in the above system, the bearing capacity of the bridge pier is increased by more than 60%. Therefore, it can be concluded that seismic strengthening techniques with CFRP sheets and mounted NSM-CFRP bars are suitable for concrete bridge piers.

Compressive Behavior of Interlocking Plastic Blocks Structural Elements Having Slenderness

Earthquakes are among of the most harmful and potentially fatal natural disasters. Masonry structures in seismic zones of urban and rural areas around the world pose a threat to human life. Housing that is both affordable and earthquake-resistant in earthquake-prone areas is currently in demand in developing countries. For affordable earthquake-resistant structures in earthquake-prone areas, numerous researchers have studied mortar-free interlocking structures. Plastic blocks are used in order to reduce the mass of the overall structure. To start with, structures under gravity are explored first because more than 95% of its design life, any structure has to withstand gravity. Prototypes of interlocking plastic-block columns, solid walls, and walls with an opening are considered for making the mortar-free structures. In this study, the effect of slenderness on the behavior of interlocking-plastic-block structural elements is investigated under compressive loading by a servo-hydraulic testing machine in the laboratory. The effect of slenderness on the behavior of one and two-block-wide structural elements was investigated in terms of the stress–strain curve, energy absorption, and toughness index under compressive loadings. Correlations between the compressive strength of interlocking-plastic-block structural elements with varying thicknesses were found. Scaled-down prototypes of interlocking-plastic-block structural elements having two-block wide depicted more resistance to compressive loads than one block wide structural elements. The correlations among the one and two block wide interlocking-plastic-block columns, single and double-block-wide solid walls, and single and double-block-width walls with an opening found in this analysis were Pdc = 2.2 Psc, Pdsw = 2.9 Pssw, and Pdwo = 3.5 Pswo. This study can be applied in the future to better understand the detailed behavior of interlocking plastic blocks.

Comparative Study of Conventional Frame and Diagonally Intersecting Metal with Geometric Irregularities

Abstract: Compare the performance of Diagrid structural system and chevron braced frame by using Staad pro software. To analyses the stability of structure in seismic zone according to comparison between bending moment diagram, shear force variation. The STAAD-PRO software is used to develop 3D rendering model and to carry out the analysis. The lateral load such as earthquake to be applied on the buildings are based on the Indian standards. The study is performed for seismic zone –IV (Delhi) as per IS 1893:2002 (Earthquake load). Keyword: Diagrid Structure, Conventional Frame, Tall Buildings, Lateral loads, Staad Pro

A machine-learning-based model for predicting the effective stiffness of precast concrete columns

Predicting effective stiffness (ES) of precast concrete columns (PCCs) is an essential topic when PCCs are applied to structures in seismic zones. However, existing researches provide nearly no method especially for predicting the ES of PCCs, partly due to the high complexity of this issue. This study aims to firstly develop a machine learning (ML) model for predicting the ES of PCCs based on voting ensemble learning (VEL) algorithm which adopted different ML algorithms: support vector regression (SVR), random forest regression (RFR), and gradient boosting tree regression (GBTR) to respectively establish three base models. 177 flexural-dominant PCCs with various construction details were collected from the literature to assemble an experimental database, in which each specimen has 42 features. A ML model establishment proceeding was conducted, involving data preparation, feature selection, and hyperparameter tuning. Experimental verification was conducted to assess the VEL, SVR, RFR, and GBTR models, under the scenarios with/without feature selection. A comparison was conducted on the prediction performance between the existing empirical formulas and the VEL model with feature selection which was further interpreted using the combination of partial dependence analysis (PDA) and individual conditional expectation (ICE). Results show that the VEL algorithm can improve the accuracy and reliability of predicting the ES of PCCs. The VEL model with feature selection is proposed because it eliminates 21 negligible features and still presents far better prediction performance compared with the empirical formulas. The effect of each of the features considered in the proposed VEL model is recognized and depicted. Besides the four parameters considered in the existing formulas, another five parameters are also identified to have non-negligible influence on the ES of PCCs. Despite some limitations such as relatively insufficient number of data points, restricted range of input parameters, and lack of mechanical explanations, the proposed VEL model still firstly provides an accessible way to predict the ES of PCCs and can give inspiration for future researchers.

Effect of shear walls on the behavior of nonlinear structures in seismic zones

1. American Society of Civil Engineers, 2000. Prestandard and commentary for the seismic rehabilita-tion of buildings. FEMA-356. Federal Emergency Management Agency, Wash-ington D.C., 519 p. Google Scholar

A Review on Multi-Storey RCC& Composite Building Under Seismic Effect using E-Tabs Software

The Steel-concrete composite constructions are commonly used in modern construction. Due to its several advantages over RCC and steel structures, composite structures consisting of steel and concrete are particularly popular. The structural members of RCC buildings are heavier and have larger cross-sections. Steel constructions have higher deflections and flexibility than concrete structures, helping resistance to earthquake loads. In composite structures, the appropriate qualities of RCC and steel structures are blended. The composite structures facilitate lower costs, quick construction, and fire protection, among other attributes. Present study covers comparison of high-rise (G+8) RCC and composite structures in seismic zone IV considering the provisions of IS: 1893 (Part1) -2002. The seismic behaviour of frames created using the suggested methodology is assessed using ETABS software's nonlinear time-history analysis and the results are compared using various parametric data, for structures in all sorts of building frames, maximum storey displacement, storey stiffness, storey drift, fundamental time periods, base shear, and weight are determined. The steel-concrete composite frames, along with RCC and steel constructions, are best suited for medium to high rise buildings, according to comparative research.

Numerical and analytical study of stainless steel beam-to-column extended end-plate connections

Based on a shell finite element modeling protocol developed and verified by the first author in a previous study, a comprehensive investigation on stainless steel extended end-plate beam-to-column connections was carried out. A total of 180 connection configurations were numerically investigated, to establish a thorough understanding of the influence of a wide range of geometrical parameters on the behavior of this connection type commonly-used in earthquake-resistant steel structures. The initial stiffness; ultimate moment; rotation capacity; dissipative energy; ductility index; and failure patterns were compared and discussed. Furthermore, based on the data acquired from this parametric study, a simple analytical method, for predicting the moment-rotation (M-Φ) characteristics of stainless steel extended end-plate connections, was developed and validated. The results demonstrate that stainless steel extended end-plate connections can be designed to have substantial ductility and rotation capacity, more than satisfactory for beam-to-column joints of structures in seismic zones. In particular, connections with end-plate stiffeners displayed superior performance with enhanced ultimate moment and energy dissipation capacity. The recommended analytical method for M-Φ response of the joints is accurate, with an average error of less than 4% for the ultimate resistance and is robust as evidenced by its prediction of M-Φ response for models that were withheld from its initial calibration. The proposed equations provide, for the first time, a powerful analytical tool that can predict the complete moment-rotation curves of unstiffened and stiffened stainless steel extended end-plate joints, using easy-to-obtain geometric and material properties.

Experimental Evaluation of Shear Behavior of Stone Masonry Wall.

The evaluation of the shear behavior of masonry walls is a first fundamental step for the assessment of existing masonry structures in seismic zones. However, due to the complexity of modelling experimental behavior and the wide variety of masonry types characterizing historical structures, the definition of masonry’s mechanical behavior is still a critical issue. Since the possibility to perform in situ tests is very limited and often conflicting with the needs of preservation, the characterization of shear masonry behavior is generally based on reference values of mechanical properties provided in modern structural codes for recurrent masonry categories. In the paper, a combined test procedure for the experimental characterization of masonry mechanical parameters and the assessment of the shear behavior of masonry walls is presented together with the experimental results obtained on three stone masonry walls. The procedure consists of a combination of three different in situ tests to be performed on the investigated wall. First, a single flat jack test is executed to derive the normal compressive stress acting on the wall. Then a double flat jack test is carried out to estimate the elastic modulus. Finally, the proposed shear test is performed to derive the capacity curve and to estimate the shear modulus and the shear strength. The first results obtained in the experimental campaign carried out by the authors confirm the capability of the proposed methodology to assess the masonry mechanical parameters, reducing the uncertainty affecting the definition of capacity curves of walls and consequently the evaluation of seismic vulnerability of the investigated buildings.

Base shear variation for irregular G+6, G+9 and G+12 structures in seismic zones IV and V for three soil types

It is attempted to expand upon the understanding on the structure’s behaviour when the seismic force, which is one of the predominant lateral forces, is applied on the structure. The base shear is calculated and compared for various variable parameters. For the three soil types the base shear is contrasted while varying the building heights of an irregularly planned structure in the seismic zones: IV and V. The structures’ heights are taken as follows: G+6, G+9, G+12 and storey height as 3m. Concluded observations talks about the amount of the variation in the base shear when the structure height and soil types are altered. While the G+9 and G+12 structures behaved identically, the G+6 structures in the medium and the soft soils fetched same results.

WITHDRAWN: Earth quake analysis of regular and irregular structures for all the soil types in seismic zone V

Abstract There has been a remarkable advancement in the research on design in the scope of engineering in the last couple of decades. There are many studies that contribute to better performance of buildings. Herein, to understand the seismic effects on a building when one of the design parameters is varying while others remaining constant, this study is conducted. The lateral forces at different levels of a structure in seismic zone V in all of the soil types are studied. The seismic loading with a varying soil conditions in the seismic zone is applied on all the structures. Both regularly and irregularly planned buildings are incorporated which are of varying heights (G + 3, G + 6, G + 9, and G + 12). The structure’s response in terms of lateral forces at all storey levels is analyzed varying the parameters. While the pattern observed is similar in regular and irregular cases, the soft soil type had higher storey shear when the storey levels increased.

Response Spectrum Analysis for Regular Multistory Structure in Seismic Zone III

Response Spectrum Analysis for Regular Multistory Structure in Seismic Zone III

Effects of Shape Memory Alloys on Response of Steel Structural Buildings within Near Field Earthquakes Zone

Base isolation is one of the effective ways for controlling civil engineering structures in seismic zone which can reduce seismic demand. Also is an efficient passive control mechanism that protects its superstructure during an earthquake. However, residual displacement of base-isolation systems, resulting from strong ground motions, remain as the main obstacle in such system’s serviceability after the earthquake. Shape Memory Alloys (SMA) is amongst the newly introduced smart materials that can undergo large nonlinear deformations with considerable dissipation of energy without having any permanent displacement afterward. This property of SMA may be utilized for designing of base isolation system to increase the structure’s serviceability. Here, a proposed semi-active isolation system combines laminated rubber bearing system with shape memory alloy, to take advantage of SMAs high elastic strain range, in order to reduce residual displacements of the laminated rubber bearing. Merits of the system are demonstrated by comparing it to common laminated rubber bearing isolation systems. It is found that the optimal application of SMAs in base-isolation systems can significantly reduce bearings’ residual displacements. In this study, OpenSees program for a three dimensional six-storey steel frame building has been used by locating the isolators under the columns for investigating the feasibility of smart base isolation systems, i.e., the combination of traditional Laminated Rubber Bearing (LRB) with the SMA, in reducing the structure’s isolated-base response to near field earthquake records are examined. Also, a new configuration of SMAs in conjunction with LRB is considered which make the system easier to operate and maintain.