FACTORS AFFECTING SEISMIC BEHAVIOUR OF REINFORCED CONCRETE STRUCTURES AFTER FIRE EXPOSURE

2019 ◽  
Vol 1 (Special Issue on First SACEE'19) ◽  
pp. 31-41 ◽  
Author(s):  
Alper Ilki ◽  
Ugur Demir
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Elevated Temperatures ◽  
Load Capacity ◽  
Lateral Load ◽  
Earthquake Risk ◽  
Fire Damage ◽  
Seismic Behaviour ◽  
Rc Structures ◽  
The Impact

In the areas under high earthquake risk, the impact of fire damage on the seismic performance of the reinforced concrete (RC) structures ought to be realistically taken into account while assessing the fire damage to develop reuse/repair/replace strategies through the remaining service life. In the scope of this study, a literature review is conducted on the changes of mechanical characteristics of concrete and reinforcement caused by a fire with a particular emphasis on the post-cooling stage. Post-cooling behaviour of RC members is different than the behaviour under elevated temperatures and hence it is of vital importance on structural seismic performance assessment after a fire. Apart from material-wise assessment methodologies, post-fire seismic performance of RC structural members is also discussed through post-fire simulated seismic loading tests conducted on full-scale cast-in-place and precast columns. The test results pointed out to a reduction in lateral load bearing capacity of the cast-in-place columns subjected to fire whereas fire-exposed precast columns demonstrated better performance in terms of residual lateral load capacity due to the lower axial load and larger heights. All columns exhibited satisfactory performance in terms of ductility.

scholarly journals Seismic Behaviour of Rc Building Located in Erbil, Iraq and Strengthening by Using Steel Frame Sections Precast Bolt-Connected Steel-Plate Reinforced Concrete

2022 ◽  
Vol 961 (1) ◽  
pp. 012012
Author(s):  
S F Sadeq ◽  
B R Muhammad ◽  
A J Al-Zuheriy
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Steel Plate ◽  
Deformation Mode ◽  
Original Structure ◽  
Seismic Behaviour ◽  
Construction Time ◽  
Rc Structures ◽  
Seismic Displacement ◽  
Before And After

Abstract This paper present outside strengthening with precast substructures, is a relatively new retrofitting approach that has recently attracted the attention of researchers. Outside strengthening with precast substructure, in contrast to member-level strengthening technologies (e.g., FRP strengthening, enlarging member section areas, and replacing rebars), is a structure-system reinforcement method that integrates the substructure and the original structure, improves overall seismic performance, and changes the deformation mode of the entire structure. The seismic capability of the exterior strengthening with precast bolt-connected steel-plate reinforced concrete is critically evaluated in this paper (PBSPC) Case studies are used to demonstrate the working principles, numerical methodologies, and design approaches. The simulation results were similar with prior studies, demonstrating that the numerical model was effective. The use of building steel representations reduces construction time, increases efficiency, and lowers costs. The goal of this technology is to lower the seismic displacement demand of nonductile. Current RC structures have steel frames connecting to the building floors. These frameworks run parallel to the structure of the building. Ganjan Life City, a building in Erbil, Iraq, is being used as a case study. The ISC 2017 and ASCE 7-10 earthquake codes were used to evaluate the building’s seismic performance before and after the reinforcement. The analysis’ findings suggest that the recommended technique is correct.

Experimental Study on Seismic Performance of RC Composite Core Walls with Steel Tube-Reinforced Concrete Columns and Concealed Steel Trusses under Eccentric Horizontal Loading

2010 ◽  
Vol 163-167 ◽  
pp. 2267-2273 ◽  
Author(s):  
Hong Ying Dong ◽  
Wan Lin Cao ◽  
Jian Wei Zhang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Load Capacity ◽  
Concrete Columns ◽  
Steel Tube ◽  
Reinforced Concrete Columns ◽  
Deterioration Process ◽  
Combined Action ◽  
Process Energy ◽  
Steel Trusses

Two 1/6 scale core walls, including one RC core wall with steel tube-reinforced concrete columns and concealed steel trusses and one conventional RC core wall, were tested under eccentric horizontal cyclic loading. The load-capacity, ductility, hysteresis characteristics, stiffness, stiffness deterioration process, energy dissipation and damage characteristics of the two specimens were compared and discussed in this paper. It shows that the seismic performance of the RC core walls under combined action could be improved by setting the concealed steel trusses in the walls and using the steel tube-reinforced concrete columns as the boundary elements.

Evaluation of Local Damage to Reinforced Concrete Panels Subjected to Oblique Impact of Rigid and Soft Missiles

2018 ◽  
Author(s):  
Akemi Nishida ◽  
Minoru Nagai ◽  
Haruji Tsubota ◽  
Yinsheng Li
Keyword(s):  
Reinforced Concrete ◽  
Simulation Method ◽  
Impact Angle ◽  
Oblique Impact ◽  
Local Damage ◽  
Empirical Formulas ◽  
Rc Structures ◽  
Impact Tests ◽  
Oblique Impacts ◽  
The Impact

Many empirical formulas have been proposed for evaluating local damage to reinforced concrete (RC) structures caused by impacts of rigid missiles. Most of these formulas have been derived based on impact tests normal to the target structures. Up to now, few impact tests oblique to the target structures have been carried out. This study has been conducted with the purpose of proposing a new formula for evaluating the local damage caused by oblique impacts based on previous experimental and simulation results. In this paper, the results of simulation analyses for evaluating the local damage to a RC panel subjected to normal and oblique impacts by rigid and soft missiles, by using the simulation method that was validated using the results of previous impact experiments. Based on the results of these simulation analyses, the effects of the rigidity of the missile as well as the impact angle on the local damage to the target structures are clarified.

scholarly journals Heating Temperature Prediction of Concrete Structure Damaged by Fire Using a Bayesian Approach

2020 ◽  
Vol 12 (10) ◽  
pp. 4225
Author(s):  
Hae-Chang Cho ◽  
Sun-Jin Han ◽  
Inwook Heo ◽  
Hyun Kang ◽  
Won-Hee Kang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Elevated Temperatures ◽  
Heating Temperature ◽  
Model Development ◽  
Estimation Model ◽  
Temperature Estimation ◽  
Rc Structures ◽  
Material Development ◽  
Rc Structure ◽  
Eurocode 2

A fire that occurs in a reinforced concrete (RC) structure accompanies a heating temperature, and this negatively affects the concrete material properties, such as the compressive strength, the bond between cement paste and aggregate, and the cracking and spalling of concrete. To appropriately measure the reduced structural performance and durability of fire-damaged RC structures, it is important to accurately estimate the heating temperature of the structure. However, studies in the literature on RC structures damaged by fire have focused mostly on structural member tests at elevated temperatures to ensure the fire resistance or fire protection material development; studies on estimating the heating temperature are very limited except for the very few existing models. Therefore, in this study, a heating temperature estimation model for a reinforced concrete (RC) structure damaged by fire was developed using a statistical Bayesian parameter estimation approach. For the model development, a total of 77 concrete test specimens were utilized; based on them, a statistically highly accurate model has been developed. The usage of the proposed method in the framework of the 500 °C isotherm method in Eurocode 2 has been illustrated through an RC column resistance estimation application.

CFD Application for Performance Based Safety Verification of Reinforced Concrete Beam in Computer Simulation Building Fire

2012 ◽  
Vol 601 ◽  
pp. 190-195
Author(s):  
Chia Chun Yu ◽  
Shih Cheng Wang ◽  
Cherng Shing Lin ◽  
Te Chi Chen
Keyword(s):  
Reinforced Concrete ◽  
Fire Protection ◽  
Fluid Dynamic ◽  
Bending Moment ◽  
Fire Intensity ◽  
Fire Damage ◽  
Rc Beams ◽  
Fire Dynamics ◽  
Rc Structures ◽  
Building Fire

More than 90% of the buildings in Taiwan use reinforced concrete (RC) structures. Before or after fire damage, whether the RC structure accord Performance Based Design (PBD) fire code or safe evaluation are important in building fire protection verification. However, obtaining fire thermal parameters detailed quantitative data from building fire tests or actual building fires are difficult. Therefore, computational fluid dynamic (CFD) integration to simulate fire scenarios has been widely utilized in fire protection engineering. This study utilizes Fire Dynamics Simulator (FDS) fire model and PHOENICS field model software to simulate fire development and beams inner temperature variation. The structural strength estimated using beam cross-sections temperature to investigate dynamic ultimate bending moment (Mu) of RC beams. This integration method can investigate the influence of different beam positions, fire intensity, fire duration and fire damage sustained (two or three faces heated) for RC beams fire protection safe verification.

scholarly journals Seismic performance assessment of RC columns with interlocking hoops

2021 ◽  
Author(s):  
Tae-Hoon Kim
Keyword(s):  
Reinforced Concrete ◽  
Performance Assessment ◽  
Seismic Performance ◽  
Evaluation System ◽  
Damage Index ◽  
Seismic Performance Assessment ◽  
Rc Columns ◽  
Rc Structures ◽  
Damage Indices ◽  
Transverse Steel

The aim of this study is to analytically assess the seismic performance of reinforced concrete (RC) columns with interlocking hoops using a novel damage index, and to provide data for developing next generation seismic design criteria. Seismic performance of RC columns is controlled by the level of confinement provided by transverse steel. Interlocking hoops are commonly used in RC columns because they can provide more effective confinement than rectangular hoops. Three RC interlocking columns were tested under a constant axial load and a cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), is used to analyze RC structures. Novel damage indices aim to provide a means of quantifying numerically the performance level in RC columns with interlocking hoops sustained under earthquake loading. The proposed numerical method for the seismic performance assessment of interlocking columns is verified by comparison with the experimental results.

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.

Seismic Performance of Masonry Infilled RC Structures via N2 Pushover Assessment Procedures: Outcomes under Different Modeling Hypotheses of a Case Study

2016 ◽  
Vol 847 ◽  
pp. 339-346
Author(s):  
Liborio Cavaleri ◽  
Fabio di Trapani ◽  
Maurizio Papia
Keyword(s):  
Seismic Performance ◽  
Performance Levels ◽  
Rc Structures ◽  
Capacity Curves ◽  
Equivalent Strut ◽  
N2 Method ◽  
Shear Demand ◽  
Assessment Procedures ◽  
The Impact

The assessment of the capacity of RC masonry infilled RC structures constitutes nowadays a still debated issue. Pushover based procedures for the evaluation of seismic performance, such as N2 method, are largely used in practice and in force in several technical codes. The latter has proved to be reliable for a large number of structural typologies, however in the case of infilled frames, the choices made on the modelling strategy may radically modify the outcomes observable from the capacity curves and the consequent performance levels achievable. In the paper, the extent of different modelling choices on the results of the application of N2 procedure is investigated by the deep analysis of a case study of a scholastic facility in Italy. Three modelling hypotheses are considered: neglecting of infills; equivalent strut macromodeling and equivalent strut macromodeling with prediction of additional shear demand arising because of the interaction with the infills. The impact of each on the capacity curves and then on the reliability of the overall N2 procedure is discussed pointing out the major criticalities.

scholarly journals Effect of Corrosion Damage on the Performance Level of a 25-Year-Old Reinforced Concrete Building

2012 ◽  
Vol 19 (5) ◽  
pp. 891-902 ◽  
Author(s):  
Hakan Yalciner ◽  
Serhan Sensoy ◽  
Ozgur Eren
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Plastic Hinge ◽  
Time Dependent ◽  
Earthquake Ground Motion ◽  
Rc Structures ◽  
Bond Slip ◽  
Structural Problems ◽  
Time Periods ◽  
The Impact

Corrosion is a long-term process resulting in the deterioration of the reinforced concrete (RC) structures. Most of the structural problems observed under the impact of either earthquakes or service loads might occur due to corrosion. Therefore, prediction of the remaining service life of a corroding RC structure plays an important role to prevent serious premature damage. In this study, a corroded, 25-year-old high school building which has been demolished at an earlier time was analyzed as a function of corrosion rate. Bond-slip relationships were taken into account in nonlinear analyses as a function of corrosion rate for different time periods (i.e., non-corroded (t: 0), existing (t: 25) and 50 years after construction); and they were used to ensure the effect of time-dependent slip rotation on the global structural behaviour by modifying the target post-yield stiffness of each structural member. Nonlinear push-over analyses were performed by defining the time-dependent plastic hinge properties as a consequence of corrosion effects. In order to define the performance levels of three different time periods, nonlinear incremental dynamic analyses (IDA) were performed for 20 earthquake ground motion records as a function of corrosion rate. Results showed that bond-slip relationship between concrete and steel is very important in evaluating the non-linear behaviour of corroded RC structures.

scholarly journals A Review of the Performance of Infilled RC Structures in Recent Earthquakes

2021 ◽  
Vol 11 (13) ◽  
pp. 5889
Author(s):  
André Furtado ◽  
Hugo Rodrigues ◽  
António Arêde ◽  
Humberto Varum
Keyword(s):  
Structural Damage ◽  
Primary Objective ◽  
Seismic Behaviour ◽  
Extensive Discussion ◽  
Infill Walls ◽  
Rc Structures ◽  
Soft Storey ◽  
Definition Of ◽  
Recent Earthquakes ◽  
The Impact

The primary objective is to present the most representative types of damage observed in reinforced concrete (RC) structures due to earthquakes. Those damages are divided according to the ten most representative types. Examples and the main reasons that could trigger each failure mechanism are presented. The definition of these damage types is supported by post-earthquake damage reconnaissance missions in Sichuan (China) in 2008, L’Aquila (Italy) in 2009, Lorca (Spain) in 2011, Emilia-Romagna (Italy) in 2012, Gorkha (Nepal) in 2015, Muisne (Ecuador) in 2016 and Chiapas (Mexico) in 2017. An extensive discussion is presented concerning the infill walls’ seismic behaviour and their interaction with the RC structural elements. The presentation of the significant learnings and findings concerning the typical damage herein presented and discussed are compared with the common Southern European construction practice. The impact of the infill walls on the rehabilitation costs of damaged RC buildings is also studied. These costs are compared to those related to the structural damage and rehabilitation of the entire building structure to understand the impact of the infill walls. Finally, a case study is presented to study the effect of implementing simplified retrofitting strategies to prevent the soft-storey mechanism, one of the most common problems observed in past earthquake events.

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