Modal Response-Based Visual System Identification and Model Updating Methods for Building Structures

2016 ◽  
Vol 32 (1) ◽  
pp. 34-56 ◽  
Author(s):  
Byung Kwan Oh ◽  
Doyoung Kim ◽  
Hyo Seon Park
Author(s):  
Takafumi Nishikawa ◽  
Hiroshi Matsuda ◽  
Makoto Shimizu ◽  
Daiki Tashiro

<p>This paper presents an approach to finite element modeling of a bridge by employing three‐dimensional shape measurement, stochastic system identification and model updating method. In the case of assessing performance of existing structures, model parameters need to be modified based on the actual behavior since the actual system often differs from the design due to some reasons. In this study, a FE model of an existing bridge is initially developed based on its three‐dimensional shape measured by laser scanning. The initial model parameters are automatically validated and modified by model updating. Model parameters such as sectional specifications of members, structural details, boundary condition and material properties are modified under optimization analysis by minimizing an objective function. The objective function is formulated as a combination of fitness on dynamic characteristics obtained by measurements and analysis. Estimations of dynamic characteristics generally fluctuate under the influence of the environment in service state. In this study, distribution of the series of estimated frequencies is assumed as a Kernel distribution and significant frequencies such as natural frequencies are classified based on the probability density of estimations. The method stably provides accurate characteristics of the bridge under several excitation states.</p>


Author(s):  
Goltsev Anatoly Grigoryevich, ◽  
◽  
Kurmangaliyev Timur Bolatovich, ◽  
Sherov Karibek Tagayevich, ◽  
Sikhimbayev Muratbay Ryzdikbayevich, ◽  
...  

This article presents the results of the research methods of structures aligning during installation in the vertical plane. The analysis and research of existing methods of structures alignment in the vertical plane, used in the conditions of enterprises engaged in the installation of metal tanks. The results of the research showed that the applied alignment methods in the vertical plane have some drawbacks, in particular, after aligning, additional calculations are required. And also for alignment of sliding timbering, columns and wall panels use some theodolites, including vertical allotment. Laser devices and theodolites with visual system were also investigated. However, all the methods considered with the use of these devices are quite time-consuming and a significant number of tools and equipment are used. A device is proposed to control the shape and location of flat surfaces using the principle of similarity of triangles allowing obtaining a straight line of intersection of lasers in space parallel to the plumb line. Developed devices are cheap, easy to use and manufacture. With the use of the proposed technique, there is no need to use several working and expensive devices. The developed devices can significantly reduce the alignment time of building structures in the vertical and horizontal planes.


2018 ◽  
Vol 18 (1) ◽  
pp. 5-19 ◽  
Author(s):  
Andy Nguyen ◽  
KA Tharindu Lakshitha Kodikara ◽  
Tommy HT Chan ◽  
David P Thambiratnam

In recent years, it has become increasingly important to develop methodologies for reliable deterioration assessment of civil structures over their life cycle to facilitate maintenance and/or rehabilitation planning processes. Several approaches have been established to address this issue mainly using Bayesian probabilistic model updating techniques with some capability to incorporate uncertainties in the updating process. However, Bayesian model updating techniques are often found to be complex and computationally inefficient as opposed to their deterministic counterparts such as conventional or hybrid techniques of sensitivity-based model updating. Nevertheless, the deterministic model updating techniques have not been well developed for sophisticated assessment applications such as deterioration evaluation. To address these issues, this article presents a novel methodology for deterioration assessment of building structures under serviceability loading conditions, based upon an improved hybrid model updating approach incorporating the use of long-term monitoring data. This is first realized by a simple but effective scheme to simulate the deterioration mechanism in serviceability loading conditions before enhanced with innovative solutions to classify structural elements as well as to handle measurement and updating uncertainties in a meaningful way. The effectiveness of the established methodology is illustrated through a benchmark 10-story reinforced concrete building which is equipped with a long-term structural health monitoring system.


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