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Collapse of the link span at Tower E9 of the San Francisco Oakland Bay Bridge due to inadequate seat lengths and anchor bolts. (Loma Prieta earthquake, 1989)
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The aim of this project is the development of a special link element in SAP 2000 able to represent the Shape-Memory Alloy properties of Nitinol. The model is based on coupled links and dampers. A set of numerical tests is reported, comparing the results with existing cases published in the literature. A practical example of seismic isolation is dev...
Citations
... Firstly, it is the translational movement and secondly is rotational movement [29][30][31]. ...
The evaluation of structural safety must be taken after each earthquake. The importance losses of life and materials carries the significance of the works in the field of earthquake engineering. The purpose of this study was to optimize and evaluate the earthquake resistance of bridge piers by adopting different cross-section forms and dimensions for bridge supports under earthquake action. Two methods of seismic design were used in the optimization and evaluation process. These methods were demand to capacity ratio (DCR) and yielding point. The results of demand to capacity ratio shown that the values of DCR for all piers forms models were increased when the dimension of pier cross section were increased and the values of DCR became less than 1.0, indicating that the increasing in dimensions leading to rise the capacity of bridge supports to carry the earthquake loads in transverse and longitudinal direction. Comparing with models, solid wall pier form had the lower value of DCR, indicating that solid wall piers were suitable in the design of bridge supports to resist the lateral loads of earthquake and it has enough stiffness and capacity under earthquake action. The results of performance points shown that the yielding points were increased when the dimensions of piers were increased for all piers form in transverse and longitudinal direction. The maximum values were appeared within support No. 1 and support No. 4. Solid wall form of pier had the higher values of yielding points, meaning that this type of piers form had higher seismic capacity and it will resist the earthquake action more than others piers form. This study recommended that to use third model for each pier form in the design of bridges structures to resist the earthquake load. Also this study was recommended to use solid wall piers as supports in construction of bridge structure within areas had earthquake action.
... Corrosion damage caused by deicing salts is considered one of the main problems that cause a bridge structure to be structurally deficient (FHWA, 2004). Therefore, there is an urgent need for proper guide for evaluation of deteriorated reinforced concrete bridge components that could assist structural engineers estimate the reserved strength of deteriorated bridges, and design cost-effective methods for retrofit (Aboutaha et al., (2013)). ...
Corrosion of reinforcing steel bars is the primary durability problem that causes degradation of
reinforced concrete structures located in aggressive environments. Severe corrosion of steel bars
decreases the load-carrying capacity of reinforced concrete members, causes bond deterioration,
reduces anchorage of steel bars, and decreases the confinement by transverse reinforcement.
Consequently, corrosion results in drop in the lateral strength of columns. Therefore, studying
response of corroded reinforced concrete columns subjected to lateral loads is necessary.
This study investigates response of corroded steel reinforced concrete columns subjected to lateral
loading and axial compressive load using a finite element model which was developed on ABAQUS
and calibrated against existing experimental tests data, by others. Lateral capacity of RC columns are
influenced by corroded longitudinal and transverse reinforcing bars. Effects of parameters such as
steel bar area loss percentage, and axial load ratio on lateral strength of columns are discussed. The
results of this investigation suggest that corrosion of steel bars has significant impact on load carrying
capacity of corroded concrete columns.
... They showed that FRP and steel jacket enhance the seismic performance of RC columns, and applying both jackets improves seismic performance better than applying one alone. A recent survey carried out on corroded RC bridges in New York State emphasized the demand for retrofitting corroded RC bridge columns, in particular, corroded lap-splice, to decrease possible damage in future seismic events [176]. ...
Chloride-induced corrosion and its effect on structural and seismic performance of reinforced concrete (RC) structures have been the topic of several research projects in past decades. This literature review summarizes the state of the art by presenting a brief description of chloride-induced corrosion, its main characteristics and influencing factors, a summary of experimental published data, and existing corrosion-induced deterioration models together with numerical and experimental methods used to evaluate corroded RC bridge pier. This literature review highlights the need for reliable deterioration models for RC structures and appropriate analysis methods are needed for design of new structures or assessment of existing civil engineering structures especially in seismic areas.
Corrosion of steel reinforcement is a major deterioration issue for the performance and efficiency of reinforced concrete (RC) bridge piers located in aggressive environments. Corrosion of steel reinforcement causes partial / total loss of steel ultimate and yield loads, reduction of cross-sectional area of steel bars. Furthermore, it reduces pier cross-section due to spalling of concrete cover, also it causes bond deterioration and reduction of transverse steel confinement. Consequently, corrosion of steel reinforcement leads to decreasing the lateral load resistance of corroded RC bridge piers.
Many studies have been conducted in the past to determine the effect of steel reinforcement corrosion on the residual flexural strength of corroded RC bridge deck slab and beams. This study mainly focuses on the investigation of corrosion deterioration profile and corrosion strengthening criteria for the corroded RC bridge piers exposed to combined seismic and axial compression loads. The behavior of corroded RC bridge piers under seismic loads simulated with cyclic lateral displacement according to ACI 374.2R-13, 2013 with different ratios of axial compression force was studied numerically, considering main structural parameters affecting on the behavior of corroded RC bridge piers.
The nonlinear 3-D finite-element model has been constructed and analyzed on ANSYS software. The constructed FE model was verified against experimental data conducted by other researchers in literature. After being verified, a total of 576 finite element models were developed to investigate the effect of main structural parameters such as corrosion level, axial force ratios, concrete compressive strength, longitudinal and transvers reinforcement ratios and aspect ratios, on the behavior of corroded RC bridge piers. RC bridge piers with insufficient transverse reinforcement and non-seismic reinforcement details are vulnerable to shear failure and loss of axial load carrying capacity, consequently the specimens of piers were classified into three main groups according to the transverse reinforcement ratios based on ACI 318-14 to simulate the behavior of corroded RC bridge piers that conforming or non-conforming to requirements of seismic designs.
In this thesis, a series of (200 x 500) mm rectangle pier cross-section as a third scale of proto type pier (600 x 1500) mm cross-section having different material properties were modeled. Corrosion level (0.0%, 10.0 % , 20.0 % and 40.0%), axial force ratios (10%, 20% and 30%), compressive strength of concrete (25 MPa and 50 MPa), longitudinal reinforcement ratios ( 1.13 %, 2.01 %, 3.14% and 4.90%), transverse reinforcement ratios [0.17% (ties Ø 8 @300 mm with 2 branches), 0.25 % (ties Ø 8 @200 mm with 2 branches) and 0.75% (ties Ø 8 @100 mm with 3 branches)], and aspect ratios (3.25, and 6.50) were studied.
Based on results obtained from the finite element analysis, a practical model was developed. The proposed practical method considers all the changes in material and geometry properties including the effect of corrosion level, axial force ratios, compressive strength, longitudinal and transvers reinforcement ratios and aspect ratios. These key parameters were incorporated into an equation to compute the lateral load resistance for corroded RC bridge piers, finally the proposed equation was verified against experimental data by other researchers.
After studying the behavior of corroded RC bridge piers exposed to seismic loads considering different structural parameters mentioned above, a new strengthening method was conducted to restore and enhance the lateral load resistance of deteriorated corroded RC bridge piers. The main aim of the strengthening technique is, not only to restore the original lateral load resistance of pier, but also to enhance the bridge pier durability. Consequently, the possibility of strengthening of corroded RC bridge piers with high corrosion level (C.R=40%) using ultra-high performance fiber RC (UHPFRC) jacketing was investigated. A nonlinear 3-D finite element analysis model to simulate the behavior of corroded RC bridge piers with UHPFRC jacket was created and verified against experimental data conducted by other researchers. After being verified against experimental data, a total of 72 Finite element models were developed to investigate several variables that affect the lateral response of corroded RC bridge piers with UHPFRC jacket. This thesis also provides readers better studying of lateral behavior of corroded RC bridge piers with detailed lateral force-displacement diagrams based on finite element analysis.
