scholarly journals New Design Concept for Bridge Restrainers with Rubber Cushion Considering Dynamic Action: A Preliminary Study

2020 ◽  
Vol 10 (19) ◽  
pp. 6847
Author(s):  
Hiroki Tamai ◽  
Chi Lu ◽  
Yoichi Yuki
Keyword(s):  
Design Concept ◽  
Seismic Retrofitting ◽  
Response Analysis ◽  
Fe Model ◽  
Dynamic Action ◽  
Current Design ◽  
Coupling Dynamic ◽  
Existing Bridges ◽  
Constituent Elements ◽  
Large Earthquakes

A bridge unseating prevention system is a safety system for bridge collapses caused by large earthquakes, beyond the assumption of aseismic design specifications. Presently, the system is generally adopted for newly constructed bridges and the seismic retrofitting of existing bridges. Cable type bridge restrainers are included in the system, and they are expected to prevent superstructures from exceeding the seat length of substructures. Although the bridge restrainer works during an earthquake, it is designed to be static in the current design. In addition, although the constituent elements of bridge restrainers include a rubber cushion to absorb energy during an earthquake, the effect is not included in the design. Thus, the current design lacks the dynamic effects of earthquakes and the cushioning effect of the rubber. Furthermore, in the case of a multi-span bridge, there is no particular decision as to where the restrainers should be placed or what kind of specifications they should have. Therefore, in this paper, a new design concept that considers the dynamic action of the earthquake and the cushioning effect of the rubber is proposed by coupling dynamic response analysis using a frame finite element (FE) model and a simple genetic algorithm (SGA).

Full scale test of a PC bridge to calibrate assessment methods

2021 ◽  
Author(s):  
Niklas Bagge ◽  
Jonny Nilimaa ◽  
Silvia Sarmiento ◽  
Arto Puurula ◽  
Jaime Gonzalez-Libreros ◽  
...  
Keyword(s):  
Prestressed Concrete ◽  
Structural Response ◽  
Sensitivity Study ◽  
Assessment Method ◽  
Full Scale ◽  
Concrete Bridges ◽  
Fractional Factorial ◽  
Fe Model ◽  
Load Carrying ◽  
Existing Bridges

<p>In this paper, experiences on the development of an assessment method for existing bridges are presented. The method is calibrated using the results of full-scale testing to failure of a prestressed bridge in Sweden. To evaluate the key parameters for the structural response, measured by deflections, strains in tendons and stirrups and crack openings, a sensitivity study based on the concept of fractional factorial design is incorporated to the assessment. Results showed that the most significant parameters are related to the tensile properties of the concrete (tensile strength and fracture energy) and the boundary conditions. A finite element (FE) model in which the results of the sensitivity analysis were applied, was able to predict accurately the load-carrying capacity of the bridge and its failure mode. Two additional existing prestressed concrete bridges, that will be used to improve further the method, are also described, and discussed.</p>

Two-Dimensional Nonlinear Earthquake Response Analysis of a Bridge-Foundation-Ground System

2008 ◽  
Vol 24 (2) ◽  
pp. 343-386 ◽  
Author(s):  
Yuyi Zhang ◽  
Joel P. Conte ◽  
Zhaohui Yang ◽  
Ahmed Elgamal ◽  
Jacobo Bielak ◽  
...  
Keyword(s):  
Lateral Spreading ◽  
Soil Liquefaction ◽  
Earthquake Response ◽  
Response Analysis ◽  
Fe Model ◽  
Two Dimensional ◽  
Foundation Soil ◽  
Soil Medium ◽  
Surface Plasticity ◽  
Earthquake Response Analysis

This paper presents a two-dimensional advanced nonlinear FE model of an actual bridge, the Humboldt Bay Middle Channel (HBMC) Bridge, and its response to seismic input motions. This computational model is developed in the new structural analysis software framework OpenSees. The foundation soil is included to incorporate soil-foundation-structure interaction effects. Realistic nonlinear constitutive models for cyclic loading are used for the structural (concrete and reinforcing steel) and soil materials. The materials in the various soil layers are modeled using multi-yield-surface plasticity models incorporating liquefaction effects. Lysmer-type absorbing/transmitting boundaries are employed to avoid spurious wave reflections along the boundaries of the computational soil domain. Both procedures and results of earthquake response analysis are presented. The simulation results indicate that the earthquake response of the bridge is significantly affected by inelastic deformations of the supporting soil medium due to lateral spreading induced by soil liquefaction.

scholarly journals SEISMIC VULNERABILITY OF REINFORCED CONCRETE BRIDGES IN PAKISTAN

2022 ◽  
Vol 28 (2) ◽  
pp. 93-105
Author(s):  
Muhammad Khalid Hafiz ◽  
Qaiser-uz-Zaman Khan ◽  
Sohaib Ahmad
Keyword(s):  
Seismic Hazard ◽  
Seismic Vulnerability ◽  
Seismic Hazard Assessment ◽  
Highway Bridges ◽  
Concrete Bridges ◽  
Seismic Retrofitting ◽  
Seismic Zone ◽  
Code Of Practice ◽  
Recent Earthquakes ◽  
Existing Bridges

Different researchers have performed seismic hazard assessment studies for Pakistan using faults sources which differ from Building Code of Pakistan (BCP 2007) with diverse standard deviations. The results of seismic hazard studies indicate that BCP requires gross revision considering micro and macro level investigations. The recent earthquakes in Pakistan also damaged bridge structures and some studies have been conducted by different researchers to investigate capacity of existing bridges. The most of bridge stock in Pakistan has been designed assuming seismic loads as 2%, 4% and 6% of dead loads following West Pakistan Code of Practice for Highway Bridges. The capacity of eight selected real bridges, two from each seismic zone 2A, 2B, 3 & 4 is checked against BCP demands. Static and dynamic analyses were performed and the piers were checked for elastic limits. It is established that piers are on lower side in capacity and the bridges in zone 2A are generally less vulnerable. Whereas the bridges in zone 2B, 3 and 4 are vulnerable from medium to very high level. Hence, an in-depth analytical vulnerability study of bridge stock particularly in high-risk zone needs to be conducted on priority and appropriate seismic retrofitting schemes need to be proposed.

Research of Longitudinal Seismic Response of Self-Anchored Cable-Stayed Suspension Bridge under Pile-Soil-Structure Interaction

2011 ◽  
Vol 255-260 ◽  
pp. 1167-1170
Author(s):  
Feng Miao ◽  
Wang Bo ◽  
Guan Ping
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Suspension Bridge ◽  
Soil Structure Interaction ◽  
Response Analysis ◽  
Fe Model ◽  
Longitudinal Displacement ◽  
Finite Element Program ◽  
Structure Interaction ◽  
Element Program

Based on scheme of Dalian gulf cross-sea bridge, in this paper, a 3-dimensional FE model for Self-anchored cable-stayed suspension bridge is established with finite element program and pile-soil-structure interaction is simulated by use of the equivalent embed fixation model. Based on the FE model, model analysis is carried out and the effects of pile-soil-structure interaction on dynamic behavior of long-span self-anchored cable-stayed suspension bridge are specially studied. The seismic response analysis result considering that pile-soil-structure interaction was compared with that of without considering such interaction. The analysis result show that interaction extend the nature period of structure, has the greatest impact to the first vibration mode; meanwhile, enlarged longitudinal displacement and moment of stiffening beam in middle of main span, longitudinal displacement on top of tower and axial force at bottom, but reduced the moment of tower at bottom. The research results provide some theoretical foundation to composite structure system.

scholarly journals Experimental Study on the Seismic Behaviour of Reinforced Concrete Bridge Piers Strengthened by BFRP Sheets

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Yong Li ◽  
Meng-Fei Xie ◽  
Jing-Bo Liu
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Plastic Hinge ◽  
Seismic Retrofitting ◽  
Bridge Piers ◽  
Strengthening Effect ◽  
Basalt Fibre ◽  
Seismic Behaviour ◽  
Ductility Capacity ◽  
Existing Bridges

With the continuous development of the ductility capacity concept for seismic design of bridges, the ductility capacity of many existing bridges does not meet the requirements of the current code for seismic performance because of the low reinforcement ratio and reinforcement corrosion of reinforced concrete (RC) piers. Because of their superior mechanical properties and low price, basalt fibre-reinforced polymer (BFRP) sheets have potential application in the seismic retrofits field of existing bridges. To study the seismic strengthening effect of RC pier columns, scaled specimens with standard reinforcement ratios, with low reinforcement ratios according to the past code and with corroded reinforcements, were designed and manufactured and then wrapped and pasted with BFRP sheets on the plastic hinge areas. Pseudostatic tests were conducted to verify the seismic performance of the strengthened and unstrengthened specimens. Experimental results showed that the ultimate flexural capacity, deformation capacity, and energy dissipation capacity of strengthened RC pier columns were superior. Especially for strengthened specimens with low reinforcement ratios or corrosion reinforcement, their seismic performance could rival than that of columns with standard reinforcement ratios, which showed the advantage of BFRP sheets in the seismic retrofitting of existing bridge piers.

SITUATION OF DESIGN AND CONSTRUCTION FOR RETROFITTING OF BUILDINGS IN THEKYRGYZ REPUBLIC

2019 ◽  
pp. 66-84
Author(s):  
Ulugbek Begaliev ◽  
Svetlana Brzev
Keyword(s):  
Seismic Retrofitting ◽  
School Buildings ◽  
Kyrgyz Republic ◽  
Existing Buildings ◽  
Steel Buildings ◽  
Structural Types ◽  
Current Design ◽  
Hazard Level ◽  
Earthquake Effects ◽  
First Time

There is a significant experience related to seismic retrofitting of existing buildings in many earthquake-prone regions of the world. Majority of older existing buildings were not designed to the seismic hazard level expected by current design codes; also, some structural types (like unreinforced masonry) are inherently more vulnerable to earthquake effects than others, e.g. well-designed reinforced concrete (RC) and steel buildings. It should be noted that seismic retrofitting of school buildings has been performed in several countries.It is proposed to effective strengthening of structures on the basis performance-design and pushover analyses, whis are an first time innovation for Kyrgyz Republic.

The Study of Color and Planning Schemes of Urban Transportation

2019 ◽  
Vol 44 (3) ◽  
pp. 20-23
Author(s):  
Minglei Zheng
Keyword(s):  
Interior Design ◽  
Design Procedure ◽  
Design Concept ◽  
Rail Transit ◽  
Regional Culture ◽  
Cultural Elements ◽  
Current Design ◽  
Long Time ◽  
The Times ◽  
Regional Design

To apply the design concept of regional design, excavate the typical culture of Chongqing for the current design, and endows the cultural elements and symbols that have lasted for a long time with a new flavor of The Times, firstly, the design concept of regional design is introduced to present and analyze typical regional cultural elements of Chongqing. Then, the cultural appeal and social influence of the design of Chongqing rail transit are analyzed, and the main entry point of the design is summarized to provide theoretical reference and method guidance for the subsequent design. Finally, after completing the theoretical framework, typical case analysis and the reference of design techniques, the design procedure of rail vehicles with Chongqing regional culture is proposed, and the shape design, exterior design and the interior design are completed, which have certain guiding significance for the regional characteristics of rail transit construction in Chongqing.

Seismic Response Analysis of Cylindrical Tanks With Initial Irregularities on Side Walls

1985 ◽  
Vol 107 (2) ◽  
pp. 107-117 ◽  
Author(s):  
H. Zui ◽  
T. Shinke
Keyword(s):  
Seismic Response ◽  
Hoop Stress ◽  
Hydrodynamic Pressure ◽  
Response Analysis ◽  
Vibrational Modes ◽  
Kinematic Equation ◽  
Current Design ◽  
Side Walls ◽  
Cylindrical Tanks ◽  
Natural Frequency Analysis

The objective of this paper is to report the findings of the study on the effects of initial irregularities on the seismic response of cylindrical tanks. The initial irregularities induce circumferential hydrodynamic pressure components of high-order modes, which are neglected in current design assumptions. Seismic response formulas for cylindrical tanks with arbitrary initial irregularities have been derived from Lagrange’s kinematic equation taking into account natural frequencies, vibrational modes and the hydrodynamic pressure. The hydrodynamic pressure in an irregular tank is evaluated by using velocity potential function. Natural frequency analysis is done by means of the transfer matrix method taking into consideration the initial hoop stress. The effect of aspect ratio H/D (H: liquid height and D: tank diameter) and the shape of initial irregularities are further examined by numerical calculations.

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