Fragility Evaluation in Building-Piping Systems: Effect of Piping Interaction With Buildings

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Yong Hee Ryu ◽  
Abhinav Gupta ◽  
Bu Seog Ju
Keyword(s):  
Large Scale ◽  
Nonlinear Models ◽  
Time History ◽  
Piping System ◽  
Nonstructural Components ◽  
Building Model ◽  
Building Models ◽  
Piping Systems ◽  
Story Building ◽  
Critical Locations

Many studies assessing the damage from 1971 San Fernando and 1994 North Ridge earthquakes reported that the failure of nonstructural components like piping systems was one of the significant reasons for shutdown of hospitals immediately after the earthquakes. This paper is focused on evaluating seismic fragility of a large-scale piping system in representative high-rise, midrise, and low-rise buildings using nonlinear time history analyses. The emphasis is on evaluating piping's interaction with building and its effect on piping fragility. The building models include the effects of nonlinearity in the performance of beams and columns. In a 20-story building that is detuned with the piping system, critical locations are on the top two floors for the linear frame building model. For the nonlinear building model, critical locations are on the bottom two floors. In an eight-story building that is nearly tuned with the piping system, the critical locations for both the linear frame and nonlinear models are the third and fourth floors. It is observed that building nonlinearity can reduce fragility due to reduction in the tuning between building and piping systems. In a two-story building, the nonlinear building frequencies are closer to the critical piping system frequencies than the linear building frequency; the nonlinear building is more fragile than the linear building for this case. However, it is observed that the linear building models give excessively conservative estimates of fragility than the nonlinear building models.

scholarly journals HOLISTIC PARAMETRIC RECONSTRUCTION OF BUILDING MODELS FROM POINT CLOUDS

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 689-695
Author(s):  
Z. Li ◽  
W. Zhang ◽  
J. Shan
Keyword(s):  
Large Scale ◽  
Traditional Approach ◽  
Holistic Approach ◽  
Point Clouds ◽  
Airborne Lidar ◽  
Reconstruction Method ◽  
Optimization Strategy ◽  
Building Roof ◽  
Building Model ◽  
Building Models

Abstract. Building models are conventionally reconstructed by building roof points via planar segmentation and then using a topology graph to group the planes together. Roof edges and vertices are then mathematically represented by intersecting segmented planes. Technically, such solution is based on sequential local fitting, i.e., the entire data of one building are not simultaneously participating in determining the building model. As a consequence, the solution is lack of topological integrity and geometric rigor. Fundamentally different from this traditional approach, we propose a holistic parametric reconstruction method which means taking into consideration the entire point clouds of one building simultaneously. In our work, building models are reconstructed from predefined parametric (roof) primitives. We first use a well-designed deep neural network to segment and identify primitives in the given building point clouds. A holistic optimization strategy is then introduced to simultaneously determine the parameters of a segmented primitive. In the last step, the optimal parameters are used to generate a watertight building model in CityGML format. The airborne LiDAR dataset RoofN3D with predefined roof types is used for our test. It is shown that PointNet++ applied to the entire dataset can achieve an accuracy of 83% for primitive classification. For a subset of 910 buildings in RoofN3D, the holistic approach is then used to determine the parameters of primitives and reconstruct the buildings. The achieved overall quality of reconstruction is 0.08 meters for point-surface-distance or 0.7 times RMSE of the input LiDAR points. This study demonstrates the efficiency and capability of the proposed approach and its potential to handle large scale urban point clouds.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 2 — Application of CCFS Method to the Multiply Supported Systems

2014 ◽  
Author(s):  
Koichi Tai ◽  
Keisuke Sasajima ◽  
Shunsuke Fukushima ◽  
Noriyuki Takamura ◽  
Shigenobu Onishi
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Time History ◽  
Piping System ◽  
History Analysis ◽  
Piping Systems ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper provides a part of series of “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. Paper is focused on the seismic evaluation method of the multiply supported systems, as the one of the design methodology adopted in the equipment and piping system of the seismic isolated nuclear power plant in Japan. Many of the piping systems are multiply supported over different floor levels in the reactor building, and some of the piping systems are carried over to the adjacent building. Although Independent Support Motion (ISM) method has been widely applied in such a multiply supported seismic design of nuclear power plant, it is noted that the shortcoming of ignoring correlations between each excitations is frequently misleaded to the over-estimated design. Application of Cross-oscillator, Cross-Floor response Spectrum (CCFS) method, proposed by A. Asfura and A. D. Kiureghian[1] shall be considered to be the excellent solution to the problems as mentioned above. So, we have introduced the algorithm of CCFS method to the FEM program. The seismic responses of the benchmark model of multiply supported piping system are evaluated under various combination methods of ISM and CCFS, comparing to the exact solutions of Time History analysis method. As the result, it is demonstrated that the CCFS method shows excellent agreement to the responses of Time History analysis, and the CCFS method shall be one of the effective and practical design method of multiply supported systems.

Seismic Proving Test of Ultimate Piping Strength: Test Results on Piping Component and Simplified Piping System

2002 ◽  
Author(s):  
Kenichi Suzuki ◽  
Y. Namita ◽  
H. Abe ◽  
I. Ichihashi ◽  
Kohei Suzuki ◽  
...  
Keyword(s):  
Large Scale ◽  
Safety Margin ◽  
Current Status ◽  
Piping System ◽  
Test Results ◽  
Seismic Safety ◽  
System A ◽  
Seismic Design Code ◽  
Piping Systems ◽  
Technical Issues

In 1998FY, the 6 year program of piping tests was initiated with the following objectives: i) to clarify the elasto-plastic response and ultimate strength of nuclear piping, ii) to ascertain the seismic safety margin of the current seismic design code for piping, and iii) to assess new allowable stress rules. In order to resolve extensive technical issues before proceeding on to the seismic proving test of a large-scale piping system, a series of preliminary tests of materials, piping components and simplified piping systems is intended. In this paper, the current status of the piping component tests and the simplified piping system tests is reported with focus on fatigue damage evaluation under large seismic loading.

Passive Seismic Protection of Building Piping Systems — A Review

2020 ◽  
Vol 20 (03) ◽  
pp. 2030001 ◽  
Author(s):  
Jie Tan ◽  
Peng Zhang ◽  
Qian Feng ◽  
Gangbing Song
Keyword(s):  
Base Isolation ◽  
State Of The Art ◽  
The State ◽  
Seismic Protection ◽  
Internal Stresses ◽  
Piping System ◽  
Seismic Safety ◽  
Nonstructural Components ◽  
Piping Systems ◽  
Passive Seismic

Piping systems are typical nonstructural components of a building. Previous investigations have reported many cases that earthquake causes damages or failures of piping system, resulting in secondary disasters. Therefore, this paper conducts a survey of the seismic damage of the piping systems of buildings and then reviews the state-of-the-art of the passive seismic protection methods. This paper proposes to classify the building piping system into rigid connected pipes, flexible connected pipes and semi-rigid connected pipes. Typical seismic damages of building pipes are presented following this classification. Then, several current seismic protection methods (including constructional measures, seismic braces, damping techniques and base isolation methods) are discussed regarding the theoretical mechanism and feasibility. Furthermore, the state-of-the-art of the building piping system and the passive protection methods with application prospects are evaluated. Based on the review, the flexible piping systems are most commonly used in existing old buildings and are more vulnerable in earthquakes due to their high flexibility. New buildings prefer the rigid connections which tend to restrain the motion of the pipe. However, the excessive stiffness of the rigid connection may cause overlarge internal stresses in both the connection and the pipe. Semi-rigid piping systems have sufficient overall stiffness and a degree of local deform ability and thus have the best seismic performance. In future studies, more research should be devoted to propose and develop new dampers suitable for piping systems, which will improve the seismic safety of building piping systems.

Passive Control of Seismic Response of Piping Systems

2005 ◽  
Vol 128 (3) ◽  
pp. 364-369 ◽  
Author(s):  
Y. M. Parulekar ◽  
G. R. Reddy ◽  
K. K. Vaze ◽  
K. Muthumani
Keyword(s):  
Passive Control ◽  
Response Spectrum ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Equivalent Linearization ◽  
Piping System ◽  
Equivalent Damping ◽  
History Analysis ◽  
Piping Systems

Passive energy dissipating devices, such as elastoplastic dampers (EPDs) can be used for eliminating snubbers and reducing the response of piping systems subjected to seismic loads. Cantilever and three-dimensional piping systems were tested with and without EPD on shaker table. Using a finite element model of the piping systems, linear and nonlinear time-history analysis is carried out using Newmark’s time integration technique. Equivalent linearization technique, such as Caughey method, is used to evaluate the equivalent damping of the piping systems supported on elastoplastic damper. An iterative response spectrum method is used for evaluating response of the piping system using this equivalent damping. The analytical maximum response displacement obtained at the elastoplastic damper support for the two piping systems is compared with experimental values and time history analysis values. It has been concluded that the iterative response spectrum technique using Caughey equivalent damping is simple and results in reasonably acceptable response of the piping systems supported on EPD.

scholarly journals Nonlinear Seismic Correlation Analysis of the JNES/NUPEC Large-Scale Piping System Tests

2008 ◽  
Author(s):  
Jinsuo Nie ◽  
Giuliano DeGrassi ◽  
Charles H. Hofmayer ◽  
Syed A. Ali
Keyword(s):  
Correlation Analysis ◽  
Test Data ◽  
Nuclear Power ◽  
Large Scale ◽  
Failure Modes ◽  
Plastic Behavior ◽  
Piping System ◽  
Highly Nonlinear ◽  
Piping Systems ◽  
The U.S

The Japan Nuclear Energy Safety Organization/Nuclear Power Engineering Corporation (JNES/NUPEC) large-scale piping test program has provided valuable new test data on high level seismic elasto-plastic behavior and failure modes for typical nuclear power plant piping systems. The component and piping system tests demonstrated the strain ratcheting behavior that is expected to occur when a pressurized pipe is subjected to cyclic seismic loading. Under a collaboration agreement between the U.S. and Japan on seismic issues, the U.S. Nuclear Regulatory Commission (NRC)/ Brookhaven National Laboratory (BNL) performed a correlation analysis of the large-scale piping system tests using detailed state-of-the-art nonlinear finite element models. Techniques are introduced to develop material models that can closely match the test data. The shaking table motions are examined. The analytical results are assessed in terms of the overall system responses and the strain ratcheting behavior at an elbow. The paper concludes with the insights about the accuracy of the analytical methods for use in performance assessments of highly nonlinear piping systems under large seismic motions.

A Test and Analysis of the Multiple Support Piping Systems

1989 ◽  
Vol 111 (3) ◽  
pp. 291-299 ◽  
Author(s):  
T. Chiba ◽  
R. Koyanagi ◽  
N. Ogawa ◽  
C. Minowa
Keyword(s):  
Large Scale ◽  
Response Spectrum ◽  
Steel Structures ◽  
Response Spectra ◽  
Piping System ◽  
Multiple Response ◽  
Actual Behavior ◽  
Test Results ◽  
Piping Systems ◽  
Multiple Support

One of the current topics in the seismic design of piping systems is the overall reliability of them in earthquake events. Actual piping systems are generally supported by independent structures such as vessels and steel structures. So, it is very important to clarify the behavior of actual piping systems during the seismic events. For this purpose, the analytical method of multiple excitation problems is a preferable approach to not only evaluate the actual behavior of the piping systems, but also improve the reliability of piping systems. To clarify the dynamic characteristics of the piping systems and to assess the computational methods in the linear system subjected to multiple support excitations, an experimental study using a realistic large-scale piping model has been conducted. The equations for the multiple excitation problem have been validated and the adequacy of the multiple response spectra method has been confirmed by the comparison of the test results with the analytical one. This paper reports the results focusing on the analytical methods of the multiple support piping system. It is noted that the multiple response spectrum method is efficient for the multiple excitation problems.

scholarly journals A modified approach to earthquake resistant design of torsionally coupled buildings

1988 ◽  
Vol 21 (2) ◽  
pp. 140-153 ◽  
Author(s):  
A. M. Chandler ◽  
G. L. Hutchinson
Keyword(s):  
Time History ◽  
Dynamic Responses ◽  
Building Model ◽  
Asymmetric Buildings ◽  
Building Models ◽  
Earthquake Resistant Design ◽  
Modal Coupling ◽  
Torsional Coupling ◽  
Lateral Displacements ◽  
Coupled Buildings

All major building codes employ empirical procedures to account for modal coupling between the lateral and torsional responses of a structure. These procedures are implemented using expressions
defining an equivalent static design torque. The provisions are based largely on the results of parametric investigations of the earthquake response of simple single-storey building models, which are found to
be representative of regular multi-storey structures. This paper presents results obtained by the analysis of the time-history earth- quake response of a single storey mono-symmetric building model, leading to the development of an alternative approach for defining the design torque for torsionally coupled buildings. The procedure is based on the concept of effective eccentricity, in which the design lateral displacements of key structural members on the edge of the building are matched to the results of a dynamic analysis. A close approximation to the dynamic responses is derived over the relevant ranges of the important parameters. These parameters include the ratio of torsional to translational natural frequencies, which strongly influences the magnitude of torsional coupling effects in asymmetric buildings.

scholarly journals Size-Adaptive Texture Atlas Generation and Remapping for 3D Urban Building Models

2021 ◽  
Vol 10 (12) ◽  
pp. 798
Author(s):  
Xuequan Zhang ◽  
Wei Liu ◽  
Bing Liu ◽  
Xin Zhao ◽  
Zihe Hu
Keyword(s):  
Large Scale ◽  
Texture Mapping ◽  
Graphics Hardware ◽  
High Fidelity ◽  
Blank Space ◽  
Web Based ◽  
Vertex Number ◽  
Building Model ◽  
Building Models ◽  
Atlas Method

A high-fidelity 3D urban building model requires large quantities of detailed textures, which can be non-tiled or tiled ones. The fast loading and rendering of these models remain challenges in web-based large-scale 3D city visualization. The traditional texture atlas methods compress all the textures of a model into one atlas, which needs extra blank space, and the size of the atlas is uncontrollable. This paper introduces a size-adaptive texture atlas method that can pack all the textures of a model without losing accuracy and increasing extra storage space. Our method includes two major steps: texture atlas generation and texture atlas remapping. First, all the textures of a model are classified into non-tiled and tiled ones. The maximum supported size of the texture is acquired from the graphics hardware card, and all the textures are packed into one or more atlases. Then, the texture atlases are remapped onto the geometric meshes. For the triangle with the original non-tiled texture, new texture coordinates in the texture atlases can be calculated directly. However, as for the triangle with the original tiled texture, it is clipped into many unit triangles to apply texture mapping. Although the method increases the mesh vertex number, the increased geometric vertices have much less impact on the rendering efficiency compared with the method of increasing the texture space. The experiment results show that our method can significantly improve building model rendering efficiency for large-scale 3D city visualization.

Use of topographic LiDAR point clouds for building reconstruction

2021 ◽  
Author(s):  
Yipeng Yuan
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Point Clouds ◽  
Building Roof ◽  
Building Model ◽  
Building Models ◽  
Urban Models ◽  
Elevation Data ◽  
3D Building Model ◽  
Building Reconstruction

Demand for three-dimensional (3D) urban models keeps growing in various civil and military applications. Topographic LiDAR systems are capable of acquiring elevation data directly over terrain features. However, the task of creating a large-scale virtual environment still remains a time-consuming and manual work. In this thesis a method for 3D building reconstruction, consisting of building roof detection, roof outline extraction and regularization, and 3D building model generation, directly from LiDAR point clouds is developed. In the proposed approach, a new algorithm called Gaussian Markov Random Field (GMRF) and Markov Chain Monte Carlo (MCMC) is used to segment point clouds for building roof detection. The modified convex hull (MCH) algorithm is used for the extraction of roof outlines followed by the regularization of the extracted outlines using the modified hierarchical regularization algorithm. Finally, 3D building models are generated in an ArcGIS environment. The results obtained demonstrate the effectiveness and satisfactory accuracy of the developed method.

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