A Damage Model for Collapse-Mechanism of Long-Span and High-Pier Continuous Rigid Frame Bridges

2011 ◽  
Vol 219-220 ◽  
pp. 1431-1435
Author(s):  
Kai Zhong Xie ◽  
Guang Qiang Chen ◽  
Li Lin Wei
Keyword(s):  
Reinforced Concrete ◽  
Strong Earthquake ◽  
Seismic Analysis ◽  
Damage Model ◽  
Collapse Mechanism ◽  
Mechanism Analysis ◽  
Long Span ◽  
Collapse Mechanisms ◽  
Rigid Frame ◽  
High Pier

Collapse-mechanism analysis can simulate that bridges enter strong elasto-plastic and large displacement response and collapses phase, so that it is very important for the seismic design of bridges. In this paper, a damage model of reinforced concrete is introduced, and dynamic response and collapse of long span and high-pier continuous rigid frame bridge during strong earthquake is studied with damage model of reinforced concrete by the explicit dynamic analysis code (LS-DYNA). The simulation results indicate the development of the concrete elements from cracking to failure and the bridge from part collapse to the whole collapse of the bridge are studied. The damage and collapse mechanisms during strong earthquake are given of Long Span and High-pier Continuous Rigid Frame Bridges. References are provided for seismic analysis of this kind of bridges.

Pier Form Selection and Parameter Analysis of Reinforced Concrete Thin-Wall High Pier

2012 ◽  
Vol 463-464 ◽  
pp. 239-243
Author(s):  
Xiao Mei Dong ◽  
Yan Wen
Keyword(s):  
Reinforced Concrete ◽  
Internal Force ◽  
Parameter Analysis ◽  
Thin Wall ◽  
Force Analysis ◽  
Nonlinear Stability Analysis ◽  
Long Span ◽  
Rigid Frame ◽  
High Pier ◽  
The Stability

Two forms of reinforced concrete pier were compared by internal force analysis and nonlinear stability analysis. According to the restriction of the stability and intensity, size optimization of the high piers’ section is calculated by means of differential coefficient. The results of the calculation and analysis indicate that the parameter optimization of the piers’ section of Long-span continuous rigid frame bridges is feasible by using the optimization model, and the results are provided to the optional design of Long-span continuous rigid frame bridges.

Seismic Vulnerability of Existing RC Buildings and Influence of the Decoupling of the Effective Masonry Panels from the Structural Frames

2012 ◽  
Vol 268-270 ◽  
pp. 646-655
Author(s):  
Fabio de Angelis ◽  
Donato Cancellara
Keyword(s):  
Reinforced Concrete ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Effective Interaction ◽  
Collapse Mechanism ◽  
Limit States ◽  
Capacity Curves ◽  
Masonry Infills ◽  
N2 Method ◽  
Structural Frame

In the present work we discuss on the seismic vulnerability of reinforced concrete existing buildings. In particular we consider a reinforced concrete building originally designed for only gravitational loads and located in a zone recently defined at seismic risk. According to the Italian seismic code NTC 2008 a displacement based approach is adopted and the N2-method is considered for the nonlinear seismic analysis. In the analysis all the masonry infill panels in effective interaction with the structural frame are considered for the nonlinear modeling of the structure. The influence of the effective masonry infills on the seismic response of the structure is analyzed and it is discussed how the effect of the masonry infills irregularly located within the building can give rise to a worsening of the seismic performance of the structure. It is shown that in the present case a not uniform positioning of the masonry infills within the building can give rise to a fragile structural behavior in the collapse mechanism. Furthermore a comparative analysis is performed by considering both the structure with the effective masonry infills and the bare structural frame. For these two structures a pushover analysis is performed, the relative capacity curves are derived and it is shown that fragile collapse mechanisms can occur depending on the irregular positioning of the effective masonry infills. Accordingly it is discussed how in the present case a decoupling of the effective masonry infills from the structural frame can give rise to a smoother response of the capacity curves. For the examined case of an obsolete building with irregular positioning of the masonry panels, the choice of decoupling the effective masonry panels from the structural frame may facilitate the retrofitting strategies for the achievement of the proper safety factors at the examined limit states.

Analysis of Sensitive Factors of Long-Span Continuous Rigid Frame Bridge’s Stability with Thin-Wall Piers in the Construction Stage

2011 ◽  
Vol 255-260 ◽  
pp. 921-925 ◽  
Author(s):  
Hai Jun Wu ◽  
Yu Qiang Kang ◽  
Lei Zhang
Keyword(s):  
Prestressed Concrete ◽  
Wind Load ◽  
Basic Theory ◽  
Thin Wall ◽  
Large Span ◽  
Long Span ◽  
Rigid Frame ◽  
Main Factors ◽  
High Pier ◽  
The Stability

Analyzing the basic theory of stability, with a high pier of large span prestressed concrete continuous bridge as the example, the stability was analyzed when constructing, considering wind load, hanging basket, pier etc. Both eigenvalue and mode are got for the longest cantilever ting condition, the sensitivity of stability to various loads being analyzed. It is concluded that the unbalanced weight and the falling of basket are the main factors.

Research on Space Simulation Methods for High-Pier Long–Span Pre-Stressed Continuous Rigid Frame Bridges

2011 ◽  
Vol 368-373 ◽  
pp. 1463-1468
Author(s):  
Jian Xun Zhao ◽  
Wei Feng ◽  
Dan Lei
Keyword(s):  
Load Capacity ◽  
Shaanxi Province ◽  
Main Beam ◽  
Thin Wall ◽  
Simulation Methods ◽  
Long Span Bridges ◽  
Long Span ◽  
Rigid Frame ◽  
Box Beams ◽  
High Pier

Along with the fact that more and more high-pier long-span bridges have been constructed in China, especially in western regions of China, the issues relevant to construction safety, load capacity have attracted duly attention of many bridge engineers. Taking Xushuihe Super Bridge of Yumenkou - Yanliang Expressway in Shaanxi Province as an example, the limited space element models including phase construction,concrete box beams, thin - wall hollow piers, pre-stressed main beam tendon, high piers, and regular reinforcement are proposed to be established in this paper. Thoughts and methods are developed for analysis of the space simulation during overall-process construction and operation, and references are given for further research on this kind of bridges.

Seismic Vulnerability of Existing RC Buildings and Influence of the Decoupling of the Effective Masonry Panels from the Structural Frames

2012 ◽  
Vol 256-259 ◽  
pp. 2244-2253 ◽  
Author(s):  
Fabio de Angelis ◽  
Donato Cancellara
Keyword(s):  
Reinforced Concrete ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Effective Interaction ◽  
Collapse Mechanism ◽  
Limit States ◽  
Capacity Curves ◽  
Masonry Infills ◽  
N2 Method ◽  
Structural Frame

In the present work we discuss on the seismic vulnerability of reinforced concrete existing buildings. In particular we consider a reinforced concrete building originally designed for only gravitational loads and located in a zone recently defined at seismic risk. According to the Italian seismic code NTC 2008 a displacement based approach is adopted and the N2-method is considered for the nonlinear seismic analysis. In the analysis all the masonry infill panels in effective interaction with the structural frame are considered for the nonlinear modeling of the structure. The influence of the effective masonry infills on the seismic response of the structure is analyzed and it is discussed how the effect of the masonry infills irregularly located within the building can give rise to a worsening of the seismic performance of the structure. It is shown that in the present case a not uniform positioning of the masonry infills within the building can give rise to a fragile structural behavior in the collapse mechanism. Furthermore a comparative analysis is performed by considering both the structure with the effective masonry infills and the bare structural frame. For these two structures a pushover analysis is performed, the relative capacity curves are derived and it is shown that fragile collapse mechanisms can occur depending on the irregular positioning of the effective masonry infills. Accordingly it is discussed how in the present case a decoupling of the effective masonry infills from the structural frame can give rise to a smoother response of the capacity curves. For the examined case of an obsolete building with irregular positioning of the masonry panels, the choice of decoupling the effective masonry panels from the structural frame may facilitate the retrofitting strategies for the achievement of the proper safety factors at the examined limit states.

Numerical Simulations of Canyon Topography Effects on Long-Span Bridge with High Piers under Incident SH Seismic Waves

2011 ◽  
Vol 378-379 ◽  
pp. 789-794
Author(s):  
Guo Liang Zhou ◽  
Xiao Jun Li ◽  
Qing Li Meng
Keyword(s):  
Oblique Incidence ◽  
Seismic Waves ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Ground Surface ◽  
Analysis And Design ◽  
Long Span ◽  
Rigid Frame ◽  
Long Span Bridge ◽  
Canyon Topography

To evaluate the influences of the canyon topography on large structures, based on a rigid frame bridge across a 137-meter-deep and 600-meter-wide canyon, the seismic response of the canyon topography is analyzed under seismic SH waves with the assumptions of vertical incidence and oblique incidence to obtain the surface ground motions, which are used as the excitations for the bridge. It indicates that canyon topography has significant and complex influences on the surface ground motions. The peak ground accelerations vary greatly from the bottom of the canyon to the upper corners. And the ground surface has been characterized by larger relative displacements in the case of oblique incidence. Compared with the uniform seismic excitations, it’s hard to find out any regularity on structural seismic responses considering the canyon topography effects. The canyon topography can enlarge or minish the structural responses in terms of the different structure members, and it should be a carefully considered factor in structural seismic analysis and design.

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