scholarly journals Effects of pounding on the behavior of reinforced concrete frame structures in seismic zone 2B

2021 ◽  
Author(s):  
Muhammad Hamid ◽  
◽  
Fayyaz Ur Rahman ◽  
Qaisar Ali ◽  
◽  
...  
Keyword(s):  
Structural Damage ◽  
Bending Moment ◽  
Frame Structures ◽  
Seismic Zone ◽  
Structural Members ◽  
Reinforced Concrete Frame ◽  
Ground Acceleration ◽  
Maximum Displacement ◽  
Analysis And Design ◽  
Axial Forces

Pounding between adjacent buildings is a common phenomenon which can be observed during moderate to high ground shakings that can result in structural damage and even loss of life. As this phenomenon is related to the life safety, therefore, it is imperative to consider it in the modelling stage of structural analysis and design. The current study is intended to evaluate, numerically, the effect of pounding phenomenon in RC frame structures. Three dimensional models of two hypothetical buildings are analyzed by subjecting to three ground acceleration histories that are scaled and matched with BCP-SP07 design spectrum. The analysis results such as inter storey drift, maximum displacement, pounding forces and its effects on bending moment, axial forces, shear and torsional forces in structural members are compared. The results show that pounding forces decrease with increase in gap size and are dominant in top five stories with maximum force at the top floor level. Pounding increase displacement up to 2 times and acceleration up to 240 times as compared to without pounding case. Pounding increase the axial forces up to 250 times and bending moment up to 2 time in the beams parallel to colliding forces. Similarly, the shear forces and torsional moments are almost doubled as a result of pounding. Finally, a 20 storey building consists of four blocks separated by 3-inch expansion joints is modelled combinedly in Etabs and analyzed to see the effect of pounding. Based on the results it is concluded that pounding must be considered at modelling stage of the design to account for the forces induced in the structural members.

scholarly journals Gaussian Process Regression-Based Structural Response Model and Its Application to Regional Damage Assessment

2021 ◽  
Vol 10 (9) ◽  
pp. 574
Author(s):  
Sangki Park ◽  
Kichul Jung
Keyword(s):  
Damage Assessment ◽  
Structural Damage ◽  
Seismic Waves ◽  
Mean Squared Error ◽  
Fragility Curves ◽  
Model Performance ◽  
Structural Response ◽  
Gaussian Process Regression ◽  
Ground Acceleration ◽  
Maximum Displacement

Seismic activities are serious disasters that induce natural hazards resulting in an incalculable amount of damage to properties and millions of deaths. Typically, seismic risk assessment can be performed by means of structural damage information computed based on the maximum displacement of the structure. In this study, machine learning models based on GPR are developed in order to estimate the maximum displacement of the structures from seismic activities and then used to construct fragility curves as an application. During construction of the models, 13 features of seismic waves are considered, and six wave features are selected to establish the seismic models with the correlation analysis normalizing the variables with the peak ground acceleration. Two models for six-floor and 13-floor buildings are developed, and a sensitivity analysis is performed to identify the relationship between prediction accuracy and sampling size. A 10-fold cross-validation method is used to evaluate the model performance, using the R-squared, root mean squared error, Nash criterion, and mean bias. Results of the six-parameter-based model apparently indicate a similar performance to that of the 13-parameter-based model for the two types of buildings. The model for the six-floor building affords a steadily enhanced performance by increasing the sampling size, while the model for the 13-floor building shows a significantly improved performance with a sampling size of over 200. The results indicate that the heighted structure requires a larger sampling size because it has more degrees of freedom that can influence the model performance. Finally, the proposed models are successfully constructed to estimate the maximum displacement, and applied to obtain fragility curves with various performance levels. Then, the regional seismic damage is assessed in Gyeonjgu city of South Korea as an application of the developed models. The damage assessment with the fragility curve provides the structural response from the seismic activities, which can assist in minimizing damage.

scholarly journals Wind Analysis of Tall Buildings for Vertical Irregularity : A Review

2020 ◽  
pp. 121-126
Author(s):  
Syed Mudassir ◽  
Kuldeep Dabhekar ◽  
Syed Faiz ◽  
Isha P. Khedikar
Keyword(s):  
Tall Buildings ◽  
Bending Moment ◽  
Wind Load ◽  
Base Shear ◽  
Structural Behaviour ◽  
Analysis And Design ◽  
Irregular Structure ◽  
Axial Forces ◽  
Tall Structures ◽  
Wind Analysis

Now every day, various buildings are being built for different purposes such as residential, commercial, and industrial etc. In general, in order to stabilize these longitudinal tall structures for both loads such as gravity and lateral (wind and earthquake) loads are required to take when considering the analysis and design. In addition to this there are several types of structures or buildings having different geometry in vertical and horizontal plan in the sense regular or irregular. This paper presents detailed review on the analysis of vertically irregular structure subjected to wind loads, the failure of structure starts from the weak point or joint. This weakness is exacerbated by the uneven distribution of mass, changes in elasticity or stiffness and also changes in the vertical geometry of the structure. Properties that have objections to physical or geometric regularity are referred to as irregular structures. The present study shows a review on analysis and effects in vertical irregular structure under lateral load especially in case of wind load. Many structural software and standard codes are reviewed for the creation of all members under wind load. At the end of this paper concerns the comparison of regular building with irregular structure and describes the effects in vertical irregular structure with the help of structural behaviour such as displacement, drift, axial forces, base shear and bending moment etc.

scholarly journals Seismic Damage Assessment of Deficient Reinforced Concrete Frame Structures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Rizwan ◽  
Syed Azmat Ali Shah
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Seismic Damage ◽  
Frame Structures ◽  
Code Design ◽  
Reinforced Concrete Frame ◽  
Ground Acceleration ◽  
Weak Beam ◽  
Test Models ◽  
Acceleration Record

Abstract In order to assess the seismic damage response of reinforced concrete deficient, weak beam-column connection frame structures, this study presents experimental shake table testing on representative 1/3rd reduced size and double story frame models. Two test models were considered for experimental testing, including a reference code design specimen and another frame with a similar characteristic, but was not provided with any shear reinforcement in the critical joint connection region and, was constructed with concrete having a compressive strength of 33 % less than the code specified value. The input scaled excitations were applied from 5 % to 130 % of the maximum input peak ground acceleration record, to deformed the test models from elastic to inelastic stage and then to fully plastic incipient collapse stage. The weak beam-column frame sustained plastic hinging at column bases and beam ends, with longitudinal reinforcement bar-slip and severe damageability of the joint panels upon subjected to multiple dynamic excitations. The deficient frame model was only able to resist 40 % of the maximum acceleration record as compared to the code design frame which was able to resist about 130 %.

scholarly journals A Simplified Approach for Analysis and Design of Reinforced Concrete Circular Silos and Bunkers

2018 ◽  
Vol 12 (1) ◽  
pp. 234-250
Author(s):  
Muhammad Umair Saleem ◽  
Hassan Khurshid ◽  
Hisham Jahangir Qureshi ◽  
Zahid Ahmad Siddiqi
Keyword(s):  
Reinforced Concrete ◽  
Design Procedure ◽  
Bending Moment ◽  
Efficient Design ◽  
Simplified Approach ◽  
Analysis And Design ◽  
Design Procedures ◽  
Axial Forces ◽  
Design Skills ◽  
Seismic Forces

Background: Reinforced concrete silos and bunkers are commonly used structures for large storage of different materials. These structures are highly vulnerable when subjected to intense seismic forces. Available guidelines for analysis and design of these structures require special design skills and code procedures. Objective: The current study is aimed to elaborate the design procedures from different sources to a unified method, which can be applied to a larger class of reinforced concrete silos. In this study, analysis and design procedures are summarized and presented in a simplified form to make sure the efficient practical design applications of reinforced concrete silos. Method: Four different cases of silo design based on the type and weight of stored material were considered for the study. For each case, the silo was designed using given design procedure and modeled using FEM-based computer package. All of the reinforced concrete silos were subjected to gravity, wind and seismic forces. Results: After performing the analysis and design of different silos, the bending moment, shear force and axial forces profiles were given for a sample silo. The results obtained from the proposed design procedure were compared with FEM values for different components of silos such as slab, wall and hopper. Conclusion: The comparison of tangential and longitudinal forces, bending moments, shear forces and reinforcement ratios of different parts of silos have shown a fair agreement with the FEM model results. It motivates to use the proposed design procedure for an efficient design of reinforced concrete silos.

scholarly journals Seismic Damage and Collapse Assessment of Reinforced Concrete Frame Structures Using a Component-Classification Weighted Algorithm

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Jizhi Su ◽  
Boquan Liu ◽  
Guohua Xing ◽  
Yudong Ma ◽  
Jiao Huang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Structural Damage ◽  
Damage Model ◽  
Seismic Damage ◽  
Frame Structures ◽  
Collapse Mechanism ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Reinforced Concrete Frame Structures

The seismic performance of reinforced concrete members under earthquake excitation is different from that of whole structures; collapse mechanism may occur because of severe damage to individual members, even if the structural damage is not significant. Therefore, the potential seismic damage of each member should be investigated specifically apart from that of overall structure. In this study, a global damage model based on component classification is proposed to analyze the structural damage evolution rule and failure mechanism; then, the computed damage is compared with the experimental phenomena of three 1/3-scale models of three-storey, three-bay reinforced concrete frame structures under low-reversed cyclic loading. In addition, a probabilistic approach is finally adopted to quantify the seismic performance of RC frame structures based on the proposed global damage model. Results indicate that the structures with lower vertical axial force and beam-to-column linear stiffness ratio still maintain a certain load-bearing capacity even when the interstorey drift angle exceeds the elastoplastic limit value and the cumulative damage of structures is mainly concentrated on the beam ends and column bottoms of the first floor at final collapse. Moreover, the structural failure probability at different performance levels would increase significantly if reinforced concrete frame structures suffer ground motions higher than the design fortification intensity, even up to eight times.

Review on Experimental Study on Effect of Corrosion In Reinforced Concrete Fly-Ash Beam

2020 ◽  
pp. 92-96
Author(s):  
Shubham N. Dadgal ◽  
Shrikant Solanke
Keyword(s):  
Fly Ash ◽  
Bond Strength ◽  
Structural Damage ◽  
Pullout Test ◽  
Partial Replacement ◽  
Structural Members ◽  
Accelerated Corrosion ◽  
Resistivity Method ◽  
Electrical Resistivity Method ◽  
Structural Failures

In modern days for structures in coastal areas it has been observed that the premature structural failures are occurs due to corrosion of the reinforcements of the designed structural member. The corrosion causes the structural damage which in turn leads to reduction in the bearing capacity of the concerned structural members. The aim of this study was to study the effect of partial replacement of fly ash to minimize the corrosion effect. Beams were designed and corroded by using artificial method known accelerated corrosion method. The beams were then tested for flexural and bond strength. Also the weight loss of the reinforced bars was been determined using electrical resistivity method. The fly ash will replace by 10% and 15%.The strength will calculate at varying percentage of corrosion at 10% and 15%. Beams will cast at M25 grade concrete. The flexural strength will test by using UTM and the bond strength will calculate using pullout test.

scholarly journals Driven Pile Effects on Nearby Cylindrical and Semi-Tapered Pile in Sandy Clay

2021 ◽  
Vol 11 (7) ◽  
pp. 2919
Author(s):  
Massamba Fall ◽  
Zhengguo Gao ◽  
Becaye Cissokho Ndiaye
Keyword(s):  
Coupling Effect ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Adaptive Mesh ◽  
Pile Driving ◽  
Arbitrary Lagrangian Eulerian ◽  
Axial Forces ◽  
Tapered Pile ◽  
Driven Pile ◽  
The Impact

A pile foundation is commonly adopted for transferring superstructure loads into the ground in weaker soil. They diminish the settlement of the infrastructure and augment the soil-bearing capacity. This paper emphases the pile-driving effect on an existing adjacent cylindrical and semi-tapered pile. Driving a three-dimensional pile into the ground is fruitfully accomplished by combining the arbitrary Lagrangian–Eulerian (ALE) adaptive mesh and element deletion methods without adopting any assumptions that would simplify the simulation. Axial forces, bending moment, and lateral displacement were studied in the neighboring already-installed pile. An investigation was made into some factors affecting the forces and bending moment, such as pile spacing and the shape of the already-installed pile (cylindrical, tapered, or semi-tapered). An important response was observed in the impact of the driven pile on the nearby existing one, the bending moment and axial forces were not negligible, and when the pile was loaded, it was recommended to consider the coupling effect. Moreover, the adjacent semi-tapered pile was subjected to less axial and lateral movement than the cylindrical one with the same length and volume for taper angles smaller than 1.0°, and vice versa for taper angles greater than 1.4°.

scholarly journals Rational Choice of Reinforcement of Reinforced Concrete Frame Corners Subjected to Opening Bending Moment

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3438
Author(s):  
Michał Szczecina ◽  
Andrzej Winnicki
Keyword(s):  
Cross Section ◽  
Bending Moment ◽  
Plasticity Model ◽  
Reinforced Concrete Frame ◽  
Moment Frame ◽  
Concrete Frame ◽  
Rational Reinforcement ◽  
Eurocode 2 ◽  
Analysis Of Results

This paper discusses a choice of the most rational reinforcement details for frame corners subjected to opening bending moment. Frame corners formed from elements of both the same and different cross section heights are considered. The case of corners formed of elements of different cross section is not considered in Eurocode 2 and is very rarely described in handbooks. Several reinforcement details with both the same and different cross section heights are presented. The authors introduce a new reinforcement detail for the different cross section heights. The considered details are comprised of the primary reinforcement in the form of straight bars and loops and the additional reinforcement in the form of diagonal bars or stirrups or a combination of both diagonal stirrups and bars. Two methods of static analysis, strut-and-tie method (S&T) and finite element method (FEM), are used in the research. FEM calculations are performed with Abaqus software using the Concrete Damaged Plasticity model (CDP) for concrete and the classical metal plasticity model for reinforcing steel. The crucial CDP parameters, relaxation time and dilatation angle, were calibrated in numerical tests in Abaqus. The analysis of results from the S&T and FE methods allowed for the determination of the most rational reinforcement details.

Design Forces for Drift and Damage Control: A Second Look at the Substitute Structure Approach

1994 ◽  
Vol 10 (2) ◽  
pp. 319-331 ◽  
Author(s):  
John F. Bonacci
Keyword(s):  
Reinforced Concrete ◽  
Damage Control ◽  
Dynamic Test ◽  
Frame Structures ◽  
Rc Frame ◽  
Test Results ◽  
Structure Approach ◽  
Maximum Displacement ◽  
Design Loads ◽  
Rc Frame Structures

This paper explores the development of a method that is useful for design of reinforced concrete (RC) frame structures to resist earthquakes. The substitute structure method, originally proposed in the 1970s, makes an analogy between viscously damped linear and hysteretic response for the purpose of estimating maximum displacement. The evolution of the method is retraced in order to emphasize its unique reliance on experimental results, which are needed to establish rules for assignment of substitute linear properties. Recent dynamic test results are used to extend significantly the calibration of the method, which furnishes design loads on the basis of drift and damage control.

Sign in / Sign up

Export Citation Format

Share Document