A Study on the Pier Scour and Seismic Capacity Assessment of Bridges

2012 ◽  
Vol 204-208 ◽  
pp. 2224-2229
Author(s):  
Yu En Huang ◽  
Chang Huan Kou ◽  
Li Chen ◽  
Chin Sheng Kao ◽  
Meng Wei Lai
Keyword(s):  
Climate Changes ◽  
Pushover Analysis ◽  
Bridge Structure ◽  
Estimation Model ◽  
Seismic Capacity ◽  
Pier Scour ◽  
Depth Limit ◽  
The Stability ◽  
Steep Slopes ◽  
Northern Taiwan

Climate changes in recent years have caused a trend of increasing rainfall in Taiwan. In addition, the rivers of Taiwan flow down steep slopes with rapid currents, and the flow is extremely turbulent in particular segments of the rivers, causing pile scours that affect the stability of bridges in the area. Based on turbulent flow theory, this paper establishes an estimation model for the pier scour depth limit of suitable bridges crossing rivers in Taiwan, according to the characteristics of the stagnation point and separation point of fluid mechanics. A bridge in northern Taiwan is analyzed according to measurements, confirming that the channel scour formula suggested in this paper demonstrates sufficient accuracy. Additionally, lateral pushover analysis is performed on the bridge to understand the seismic durability of the bridge structure following a scour.

Seismic capacity estimation of a reinforced concrete containment building considering bidirectional cyclic effect

2018 ◽  
Vol 22 (5) ◽  
pp. 1106-1120
Author(s):  
Zhi Zheng ◽  
Changhai Zhai ◽  
Xu Bao ◽  
Xiaolan Pan
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Geometric Mean ◽  
Pushover Analysis ◽  
Incremental Dynamic Analysis ◽  
Dissipated Energy ◽  
Seismic Capacity ◽  
Capacity Estimation ◽  
Earthquake Intensity ◽  
Static Pushover Analysis

This study serves to estimate the seismic capacity of the reinforced concrete containment building considering its bidirectional cyclic effect and variations of energy. The implementation of the capacity estimation has been performed by extending two well-known methods: nonlinear static pushover and incremental dynamic analysis. The displacement and dissipated energy demands are obtained from the static pushover analysis considering bidirectional cyclic effect. In total, 18 bidirectional earthquake intensity parameters are developed to perform the incremental dynamic analysis for the reinforced concrete containment building. Results show that the bidirectional static pushover analysis tends to decrease the capacity of the reinforced concrete containment building in comparison with unidirectional static pushover analysis. The 5% damped first-mode geometric mean spectral acceleration strongly correlates with the maximum top displacement of the containment building. The comparison of the incremental dynamic analysis and static pushover curves is employed to determine the seismic capacity of the reinforced concrete containment building. It is concluded that bidirectional static pushover and incremental dynamic analysis studies can be used in performance evaluation and capacity estimation of reinforced concrete containment buildings under bidirectional earthquake excitations.

Zeros of a Class of Transcendental Equation with Application to Bifurcation of DDE

2016 ◽  
Vol 26 (04) ◽  
pp. 1650062 ◽  
Author(s):  
Kit Ian Kou ◽  
Yijun Lou ◽  
Yong-Hui Xia
Keyword(s):  
Small Parameter ◽  
Climate Changes ◽  
Transcendental Equation ◽  
Bifurcation Parameter ◽  
Parameter Perturbation ◽  
Distribution Of Zeros ◽  
World Model ◽  
The Real ◽  
Stability And Bifurcations ◽  
The Stability

Zeros of a class of transcendental equation with small parameter [Formula: see text] are considered in this paper. There have been many works in the literature considering the distribution of zeros of the transcendental equation by choosing the delay [Formula: see text] as bifurcation parameter. Different from standard consideration, we choose [Formula: see text] as bifurcation parameter (not the delay [Formula: see text]) to discuss the distribution of zeros of such transcendental equation. After mathematical analysis, the obtained results are successfully applied to the bifurcation analysis in a biological model in the real word phenomenon. In the real world model, the effect of climate changes can be seen as the small parameter perturbation, which can induce bifurcations and instability. We present two methods to analyze the stability and bifurcations.

scholarly journals Microhabitats Affect Population Size and Plant Vigor of Three Critically Endangered Endemic Plants in Southern Sinai Mountains, Egypt

Land ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 86 ◽  
Author(s):  
Amal M. Fakhry ◽  
Ali El-Keblawy ◽  
Hatem A. Shabana ◽  
Ibrahim El Gamal ◽  
Amir Shalouf
Keyword(s):  
Climate Change ◽  
Population Size ◽  
Endemic Species ◽  
Climate Changes ◽  
Small Population ◽  
Critically Endangered ◽  
High Mountains ◽  
Habitat Types ◽  
Growing Seasons ◽  
Steep Slopes

Endemic species on mountains often have narrow altitudinal ranges and are more threatened at the higher altitudes, especially with climate changes. However, plants could use special microhabitats at the mountain tops as proper places for surviving the climate change (i.e., refugia). We assessed population attributes of three critically endangered endemic species (Primula boveana Decne ex Duby, Rosa arabica Crep., and Silene leucophylla Boiss.) in two growing seasons (2006/2007 and 2013/2014), differing in the received rainfalls in microhabitats at the high mountains of southern Sinai. Both P. boveana and S. leucophylla had very small population size, but significantly increased in the 2013/2014 growing season which received above average rainfalls. The population of R. arabica is the smallest (around 40 individuals) and did not increase, even after the increase in rainfalls. Whereas P. boveana is present in fewer sites and grew in small number of specific microhabitats, both S. leucophylla and R. arabica were recorded in most studied sites and habitat types. Unlike R. arabica, both P. boveana and S. leucophylla were recorded in caves and steep slopes and on the top of the mountains. This indicates that these sheltered mist microhabitats are the best for future conservation of these species after climate change.

A GENERALIZED WIDTH FUNCTION OF FRACTAL RIVER NETWORK FOR THE CALCULATION OF HYDROLOGIC RESPONSES

Fractals ◽  
2002 ◽  
Vol 10 (02) ◽  
pp. 157-171 ◽  
Author(s):  
PENG-JUI WANG ◽  
RU-YIH WANG
Keyword(s):  
River Network ◽  
Hydrologic Response ◽  
Unit Hydrograph ◽  
Estimation Model ◽  
Analytical Results ◽  
Width Function ◽  
Instantaneous Unit Hydrograph ◽  
Self Similar ◽  
Hydrologic Responses ◽  
Northern Taiwan

An approach to apply the fractal concept to estimate hydrologic response is proposed in this paper by matching suitable self-similar networks (SSNs) to a specific watershed, and modeling the runoff with a width-function based geomorphologic instantaneous unit hydrograph (WF-GIUH). In order to work out the identification between a specific basin and SSNs that are generated by an interior generator cooperating with an exterior generator, a generalized width function is derived. Subsequently, cumulative width functions on the basis of the derived function, as well as the informational entropies are used as criteria to decide the best patterns of the two cooperating generators for the specific watershed. The WF-GIUH model is then applied to calculate the runoff of this watershed as an outcome of the estimation. To assess the adaptability of the estimation model, San-Hsia watershed of Northern Taiwan is selected as a study area, where the analytical results of the outflow estimation indicate that the fractal algorithm has been implemented successfully for the calculation of hydrologic responses.

Studies and Improvements on Modal Pushover Analysis and Application on Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 4076-4082
Author(s):  
Ying Na Mu ◽  
Lei Shi ◽  
Zhe Zhang
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
High Accuracy ◽  
Analysis Procedure ◽  
Bridge Structure ◽  
Higher Modes ◽  
Modal Pushover Analysis ◽  
Multi Mode ◽  
Inertia Forces ◽  
Modal Pushover

Because the traditional pushover analysis can not take the contributions of higher modes into account, To overcome this limitation, a modal pushover analysis procedure (MPA) is proposed by some researchers, which can involve the combination of multi-mode contributions to response. In this paper, much improvement on MPA procedure is made with consideration of the changes of seismic response after structural yielding and anew distribution of inertia forces. The method is verified by one example of bridge structure. It is concluded that the improvement part-sectionalized MPA presented in this paper has high accuracy.

scholarly journals Stability Analysis of Aifa Bridge Abutment in Fafurwar District, Bintuni Bay Regency, West Papua Province

2019 ◽  
Vol 2 (2) ◽  
pp. 162-171
Author(s):  
Muhammad Yunus ◽  
Zharin F Syahdinar
Keyword(s):  
Stability Analysis ◽  
Service Life ◽  
Safety Factor ◽  
Public Works ◽  
Bridge Structure ◽  
Construction Work ◽  
The Road ◽  
Bridge Abutment ◽  
West Papua ◽  
The Stability

In the construction of public works infrastructure, especially road infrastructure works, bridge construction work plays a very important role besides the construction of the road itself. One of the things that deserves the attention of the planners in designing a bridge structure is the design of the substructure, this is because the substructure determines the quality and service life of a bridge. In addition, at present many cases of bridge structure failures are caused by failures of the substructure in holding the load acting on the bridge. The aim of this study was to determine the stability of the abutment to sliding failure and the stability of the abutment to overturning failure on the construction of the Aifa bridge in the Bintuni Bay Regency. From the results of the calculation of the stability of the abutments to sliding failure, when the abutments are in normal conditions was obtained safety factor (SF) values 1,907, in condition of the upper structure load is not working was obtained safety factor (SF) values 1,045 and during earthquake conditions was obtained safety factor (SF) values 1,419. While the results of the calculation of the stability of the abutments to overturning failure, when the abutments are in normal conditions was obtained safety factor (SF) values 4,640, in condition of the the upper structure load is not working was obtained safety factor (SF) values 1,658 and during earthquake conditions was obtained safety factor (SF) values 3,159. Because obtained safety factor (SF) values greater than 1, so that the stability of the abutment is safe to sliding failure and overturning failure.

scholarly journals The Influence of Climatic Variations on the Stability of Wheat Plant Height

2018 ◽  
Vol 1 (1) ◽  
pp. 508-514
Author(s):  
Steliana Paula Barbu ◽  
Aurel Giura ◽  
Daniel Cristina ◽  
Călina Petruţa Cornea
Keyword(s):  
Plant Height ◽  
Climate Changes ◽  
Selection Process ◽  
Wheat Plant ◽  
Selected Lines ◽  
Breeding Programs ◽  
Climatic Variations ◽  
The Stability ◽  
Dh Lines ◽  
Or Genes

Abstract The decrease of variability sources and the genotypes instability as a result of climate changes from the last years were issues addressed in the breeding programs. For breeders the stability of some parameters like plant height is very important in selection process, therefore the influence of climatic variations it is aimed to be reduced by genetic response of the genotypes. Semi-dwarf genotypes are preferred by breeders because in this way is avoided the lodging risk. A set of 307 mutant and mutant/recombinant wheat DH lines, along with parental genotypes, was analyzed in three different years for plant height and the semi-dwarf selected lines were evaluated for stability of this parameter. The material was also analyzed for the presence of Lr34, or genes and 1A/1R translocation. In our study the reduced plant height and its stability was not associated with any of the genetic background

scholarly journals Effects on a Nearby Bridge of Dismantling Temporary Lining During Excavation of a Shallow-Buried Rectangular Tunnel

2021 ◽  
Vol 9 ◽  
Author(s):  
Guilin Sheng ◽  
Sen Wen ◽  
Fei Wu ◽  
Shixing Liu ◽  
Zhengzheng Wang
Keyword(s):  
Large Scale ◽  
Structural Deformation ◽  
Physical Situation ◽  
Bridge Structure ◽  
Tunnel Excavation ◽  
Bridge Span ◽  
Novel Method ◽  
The Stability ◽  
Restraining Force ◽  
Rectangular Tunnel

It is almost inevitable that when a tunnel is excavated in an urban area, it will pass under an existing bridge. During tunnel excavation, a temporary lining is installed and subsequently removed. However, dismantling temporary lining may affect the stability of a nearby bridge. A numerical model was created and tests were conducted on a large-scale physical model to investigate the effects of dismantling temporary lining on a nearby bridge structure. A novel method of modeling the restraining force at the top of a pier was introduced to make the model more accurate in representing the physical situation. Analysis of the results led to the following conclusions and suggestions. 1. The process of removing temporary lining can have a significant impact on surface settlement and structural deformation of the bridge. 2. The effect of removing the second half temporary lining is greater than that of removing the first half. The key range of the tunnel where this phenomenon is principally observed contains one section of tunnel ahead (i.e., in the direction of tunnel advance) of the bridge span and the two sections to the rear. 3. A 6 m–3 m–6 m mixed dismantling method is recommended for use in the key range, and a rigid cap-connection method is proposed to counteract the considerable effects of dismantling temporary lining.

scholarly journals Modelling and Evaluation of the Seismic Capacity of Typical Brick URM Buildings of the Historical Center of Cuenca- Ecuador

2021 ◽  
Vol 1203 (3) ◽  
pp. 032123
Author(s):  
José Calderón-Brito ◽  
Juan Jiménez-Pacheco
Keyword(s):  
Seismic Vulnerability ◽  
Lateral Displacement ◽  
Pushover Analysis ◽  
Brick Masonry ◽  
Seismic Events ◽  
Seismic Action ◽  
Seismic Capacity ◽  
Historic Center ◽  
Built Heritage ◽  
The City

Abstract The Historic Center of Cuenca (HCC) is located in the southern region of Ecuador. It is well known that our country is located on the so-called belt of fire of the Pacific Ocean, this area is characterized by having generated the most important seismic events in the history of mankind. More specifically, there are records that show that in the last 200 years the city of Cuenca has been exposed to earthquakes that have produced moderate to severe damage. These reasons make it possible to establish that the city of Cuenca and specifically its historic center could present important problems in the face of significant seismic events. Most of the buildings in the HCC date back to the middle of the 20th century and have used unreinforced brick masonry (brick-URM) to build their walls. This work is part of the Seismic Vulnerability Project: Seismic Damage Scenarios of the Built Heritage of the Historic Center of Cuenca. In the context of this vulnerability project, the objective of this work was to establish a family of pushover curves for three unreinforced brick masonry buildings typical of the HCC, based on a parametric pushover analysis. The definition of the typical buildings was based on an extensive work of architectural and geometric characterization of the traditional built heritage of HCC. On the basis of focusing the study on two-story buildings (the most common), the size of the floor area of the buildings (small, medium and large area) was assumed as a base parameter. Based on an analysis of the variability of different geometric and mechanical characteristics, and in order to study their influence on the pushover curves of the three typical brick URM buildings, the following study parameters were defined: 1) compressive strength of brick masonry, 2) lateral displacement capacity of brick-URM elements, 3) wall thickness. The pushover analysis was carried out with the Ruaumoko program. The model of the buildings responds to an equivalent portal frame macro-model scheme that has been formulated and validated by the authors of this paper. In order to consider the effects of the flexible floor on the dynamic response of this type of structures, a lateral load pattern that takes into account the contribution of higher order modes of vibration will be used in pushover analysis. The results will be discussed in terms of the incidence of the variability of the study parameters on the basic characteristics of the pushover curves. These results will be an essential input for the next stage of the project consisting of damage estimation for different levels of seismic action expected in the city.

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