Maximum Displacement Of Structure Research Articles

FINITE ELEMENT SIMULATION OF LOW-RISE SCHOOL BUILDING MODEL WITH SEISMIC LOADS INPUT

Earthquake impacts on buildings have garnered increased attention as Malaysia experiences seismic activities, notably from nearby regions like Sumatra and within areas such as Sabah. Despite this, current Malaysian design guidelines, such as BS 8110, do not fully incorporate seismic loads. This study addresses this gap by examining the structural performance of a scaled 1:8 model of a three-storey, low-rise school building under various peak ground accelerations (PGA) from 0.1g to 1.0g. Utilizing ABAQUS finite element simulation and time-history analysis, we evaluated the seismic responses, including local deformations, von Mises stress, and principal stresses. Key findings reveal a maximum structural displacement of 10.22 mm at 1.0g PGA, with significant stress concentrations observed at the column footings, highlighting critical areas for design improvement in seismic resilience.

Seismic Optimization for Hysteretic Damping-Tuned Mass Damper (HD-TMD) Subjected to White-Noise Excitation

The hysteretic damping tuned mass damper (HD-TMD) is composed of a spring element, a hysteretic damping (HD) element, and a mass. The HD force is proportional to the displacement of the tuned mass damper (TMD). Recently, the application of HD-TMD has emerged, but its optimal design is still lacking. To fill this academic gap, numerical solutions for optimal parameters of HD-TMD subjected to white-noise excitation were obtained based on the H2 optimization criterion. Performance balance optimization with a weighting factor was carried out to improve the response of a structure with the HD-TMD system. A set of earthquake records and harmonic excitations were conducted to prove the effectiveness of the optimal numerical solutions and the performance balance design. It was found that the performance of the HD-TMD is slightly better than that of the traditional optimized TMD. As a real TMD application of HD-TMD, the variable friction pendulum TMD (VFP-TMD) was selected to experience earthquakes with the proposed optimal methods. Results showed that the optimal solutions provided the best performance but raised the problem of difficulty in maintaining linearity with a large displacement. Nevertheless, the performance balance design helped reduce this defect and provided impressive seismic mitigation capacity. Compared with the optimal numerical solution results, the performance balance design demonstrated 2.847% of loss in the maximum structural displacement reduction rate and 3.709% of loss in the root mean square reduction rate during the earthquake-excited period, respectively.

Development of Models for Prompt Responses from Natural Disasters

This study aims to provide an enhanced model for rapid responses from natural disasters by estimating the maximum structural displacement. The linear regression, support vector machine, and Gaussian process regression (GPR) models were applied to obtain displacement estimates. Further, normalization (NM) and standardization (SD) of variables, and principal component analysis (PCA) were applied to improve model performance. The k-fold cross-validation approach was used to assess the results from the models based on the root-mean-square error and the R-squared indices. According to the results, the GPR model with NM and SD tended to provide the best estimates among the three models. The model that was based on a PCA value of 97% yielded better displacement estimation than the models with PCA values of 95% and 100%. Based on the displacement estimation, the maximum inter-story drift ratio was used to produce the fragility curve that can be used for risk assessment. The fragility curve parameters obtained from the actual numerical and predicted models were investigated and yielded similar responses. The proposed model can thus provide accurate and quick responses in disaster case by rapidly predicting the structural damage information.

Estimation of peak wind response of building using regression analysis

The maximum along-wind displacement of a considerable amount of building under simulated wind loads is computed with the aim to produce a simple prediction model using multiple regression analysis with variables transformation. The Shinozuka and Newmark methods are used to simulate the turbulent wind and to calculate the dynamic response, respectively. In order to evaluate the prediction performance of the regression model with longer degree of determination, two complex structural models were analyzed dynamically. In addition, the prediction model proposed is used to estimate and compare the maximum response of two test buildings studied with wind loads by other authors. Finally, it was proved that the prediction model is reliable to estimate the maximum displacements of structures subjected to the wind loads.

Hydroelastic analysis of surface-piercing propeller through one-way and two-way coupling approaches

Semi-submerged operation of surface-piercing propellers can cause severe structural stress and deflection due to the high-rate variation of the hydrodynamic loads on each blade in one cycle of revolution. Therefore, a proper hydroelastic analysis regarding these propellers seems imperative. Accordingly, in this article, hydrodynamic performance of a surface-piercing propeller is studied by considering the structural flexibility. The one-way and two-way coupled unsteady Reynolds-averaged Navier–Stokes equations (finite volume method used for the fluid analysis) and direct finite element method (used for the structural analysis) are utilized to analyze an 821-b surface-piercing propeller model. The obtained ventilation patterns and hydrodynamic loads on a single blade of this propeller are compared with the published experimental data. ANSYS multiphysics solvers are used to conduct the targeted simulations. The results are presented for different velocity ratios in the range of [0.8, 1.2] and Froude number Fr = 6.0. The blade maximum deformation and von Mises stress are presented in one cycle of revolution. Based on the obtained results, one may conclude that both the adopted approaches predict the propeller transient hydrodynamic characteristics with good accuracy, compared with the experimental data. However, the two-way approach displays lower maximum structural displacement and stress than one-way simulation. This is attributed to the fact that the two-way approach takes into consideration the added mass and damping effects of the surrounding fluid around the blade.

Shake Table Testing of a Low Damage Steel Building with 2-4 Displacement Dependent (D3) Viscous Damper

To improve seismic structural performance, supplemental damping devices can be incorporated to absorb seismic response energy. The viscous fluid damper is a well-known solution. However, while they reduce displacement demand, they can increase overall base shear demand in nonlinear structures as they provide resistive forces in all four quadrants of force-displacement response. In contrast, Direction and Displacement Dependent (D3) viscous fluid dampers offer the opportunity to simultaneously reduce structural displacements and the total base-shear force as they only produce resistive forces in the second and fourth quadrants of a structural hysteresis plot. The research experimentally examines the response of a half-scale, 2-storey moment frame steel structure fitted with a 2-4 configuration D3 viscous fluid damper. The structure is also tested with conventional viscous dampers to establish a baseline response and enable comparison of results. Dynamic experimental tests are used to assesses the base shear, maximum drift and residual deformation under 5 different earthquakes (Northridge, Kobe, Christchurch (CCCC), Christchurch (CHHC), and Bam ground motion). Response metrics including base shear, the maximum structural displacement, and peak structural accelerations are used to quantify performance and to assess the response reductions achieved through the addition of dampers. It is concluded that only the 2-4 device is capable of providing concurrent reductions in all three of these structural response metrics.

Assessment of the Design Criteria Effect on Performance of Multiple Tuned Mass Dampers

In this research, the effect of different design criteria on performance of multiple tuned mass dampers (MTMDs) under earthquake excitation has been studied. For optimal design of MTMDs, the parameters of TMDs are determined based on minimizing an objective function. Two different objective functions including minimizing (a) the Hankel's norm; and (b) the maximum displacement of structure have been selected using Distributed Genetic Algorithms (DGAs) for solving the optimization problem. For numerical simulation, the method has been utilized on an eight-storey shear frame and optimal MTMDs have been designed. Results show that using the Hankel's norm as the objective function has led to design MTMDs which are effective in reducing the root-mean-square (RMS) of structural response under different earthquakes while in reducing the maximum response both design criteria have had the same results. Through numerical analysis the effect of design record, MTMDs mass ratio, TMD's number and stroke length on MTMDs effectiveness has been studied.

A Simple Method of Calculating Safety Vibrating Velocity for Single-Layer Masonry Structures in Blasting Construction

Blasting-induced seismic wave imposes cyclic loadings on adjacent buildings and structures with a combined loading mode of tension, compression, bending, shear and torsion, and it leads to flaking of floated coat, wall cracking, developing of original cracks, etc. This paper presents a blasting case study for the excavation of Wucun tunnel in Xiamen Success Avenue. Field monitoring and numerical calculation of a typical brick masonry structure are adopted to analyze the relationships among the maximum structural displacement, peak vibration velocity of blasting-induced foundation vibration and the change rate of crack width. On the basis of the study above, a method of calculating the safe vibrating velocity for single-layer masonry structure is proposed. Meanwhile, a suggested value of the safe vibrating velocity for single-layer masonry structure is given. All the research results can be useful for the similar construction and research.

Design of supplemental viscous dampers in inelastic SDOF system based on improved capacity spectrum method

A simplified yet effective design procedure for viscous dampers was presented based on improved capacity spectrum method in the context of performance-based seismic design. The amount of added viscous damping required to meet a given performance objective was evaluated from the difference between the total demand for effective damping and inherent damping plus equivalent damping resulting from hysteretic deformation of system. Application of the method is illustrated by means of two examples, using Chinese design response spectrum and mean response spectrum. Nonlinear dynamic analysis results indicate that the maximum displacements of structures installed with supplemental dampers designed in accordance with the proposed method agree well with the given target displacements. The advantage of the presented procedure over the conventional iterative design method is also highlighted.

Behavior and design of structures with buckling-restrained braces

Energy dissipation capacity and earthquake response of steel structures installed with buckling-restrained braces (BRB) were investigated, and a straightforward design procedure to meet a given target displacement was developed. A formulation for optimum yield strength of BRB that maximize the equivalent damping ratio was derived, and nonlinear dynamic time-history analyses were carried out to investigate the seismic response of model structures with BRB. The analysis results show that the maximum displacements of structures generally decrease as the stiffness of the brace increases, and that the maximum displacement of the model structures designed in accordance with the proposed method corresponds well with the given target displacement.

Metodología de modelación de escenarios de riesgo sísmico en Managua, Nicaragua

La investigación Metodología de Modelación de Escenarios de Riesgo Sísmico en Managua, Nicaragua fue ejecutada por el proyecto REDUCCION DEL RIESGO SISMICO EN CENTROAMERICA (RESIS II) en su fase II, bajo el auspicio del Centro de Prevención de Desastres en América Central (CEPREDENAC), del cual la Universidad Nacional de Ingeniería (UNI) es parte. Dicha investigación presenta los análisis y resultados de la actualización de la amenaza sísmica, zonificación tectónica y aceleraciones espectrales (PGA) esperadas de Centroamérica y en particular de Managua, Nicaragua. Se presentan formatos de recopilación de información y también algunos ejemplos de los resultados obtenidos de los datos de campo levantados directamente de las edificaciones de viviendas de un barrio de Managua, así como de una extrapolación lograda sobre la base de datos catastrales de la ciudad de Managua. A partir de una muestra de viviendas típicas se establece una clasificación o tipología por cada sistema constructivo a los cuales se les aplico el Método de Análisis Estático No Lineal de Estructuras (PUSHOVER) generándose un análisis de la capacidad de la estructura acorde con una demanda y por ende el punto de desempeño, el cual representa el Máximo Desplazamiento Estructural esperado para un sismo dado y así reflejar el grado de vulnerabilidad. Finalmente, se presenta una guía de usuario del software denominado SELENA (SEismic Losses EstimatioN through a logic tree Aproach) diseñado para aplicarse a esta investigación, con el objetivo de lograr la modelación del riesgo sísmico para Managua. Palabras claves: vulnerabilidad, prevención de desarstres, aceleraciones espectrales, método no lineal.DOI: http://dx.doi.org/10.5377/nexo.v23i1.34Nexo: Revista Científica Vol. 23, No. 01, pp.09-17/Mayo 2010