Seismic design and assessment of risk-targeted reduction factor for a reinforced concrete pipe rack – piping system

2020 ◽  
Author(s):  
George Karagiannakis
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Structural Parameters ◽  
Limit State ◽  
Input Parameter ◽  
Reduction Factor ◽  
Eurocode 8 ◽  
Piping System ◽  
Seismic Action ◽  
Concrete Pipe

The procedure for estimating a target risk for adverse consequences of earthquakes should be developed in close cooperation with stakeholders and decision-makers who understand the high impact of the potential failure of industrial facilities on society and business state. However, the conventional procedures for earthquake-resistant design of critical infrastructures are not developed to such a level that would make it possible to use a target risk as an input parameter for designing the structures. This issue can be overcome by introducing the risk-based formulation for the evaluation of seismic design action for force-based design. In such an approach, the reduction factor depends on a target probability of exceedance of a designated limit state and takes into account the ground-motion randomness and uncertainty. In general, the formulation of the risk-targeted reduction factor depends on the code format for the reduction of seismic action. In this paper, the Eurocode’s format of force-based design is used. Therefore, the reduction of seismic action is accounted for by the behaviour factor.Several structural parameters have to be assumed in order to estimate the risk-targeted behaviour as discussed in the paper. In virtue of poor knowledge concerning the nonlinear response of pipe rack – piping systems, it is very challenging to appropriately assume these parameters. Thus, a reinforced concrete pipe rack, which represents a part of a liquified natural gas terminal, was firstly modelled and designed according to Eurocode 8 accounting for the low and high probability of earthquake recurrence aimed at designing the system for damage and life safety objective, respectively. The pipe rack, the piping system and the interaction of the pipe rack – piping system with the adjacent storage tank were explicitly considered in the 3D model, which provided full dynamic coupling of the three components of the analysed system.The seismic performance assessment of the pipe rack and piping system was performed by the incremental dynamic analysis using a set of 11 spectrum compatible ground motions. Based on the results of IDA analysis, the design of pipe rack was evaluated on the safe side, however, the pipelines presented higher vulnerability due to a number of assumptions that are discussed. For the presented example, it was shown that the behaviour factor for the design of the pipe rack – piping system is controlled by the performance of the pipes and not the structure supporting the pipes.

Seismic response of structural walls: recent developments

2001 ◽  
Vol 28 (6) ◽  
pp. 922-937 ◽  
Author(s):  
T Paulay
Keyword(s):  
Reinforced Concrete ◽  
Seismic Response ◽  
Seismic Design ◽  
Limit State ◽  
Lateral Force ◽  
Structural Walls ◽  
Structural Class ◽  
Response Component ◽  
Displacement Ductility ◽  
Ductility Capacity

It is postulated that for purposes of seismic design, the ductile behaviour of lateral force-resisting wall components, elements, and indeed the entire system can be satisfactorily simulated by bilinear force–displacement modeling. This enables displacement relationships between the system and its constituent components at a particular limit state to be readily established. To this end, some widely used fallacies, relevant to the transition from the elastic to the plastic domain of behaviour, are exposed. A redefinition of stiffness and yield displacement allows more realistic predictions of the important feature of seismic response, component displacements, to be made. The concepts are rational, yet very simple. Their applications are interwoven with the designer's intentions. Contrary to current design practice, whereby a specific global displacement ductility capacity is prescribed for a particular structural class, the designer can determine the acceptable displacement demand to be imposed on the system. This should protect critical components against excessive displacements. Specific intended displacement demands and capacities of systems comprising reinforced concrete cantilever and coupled walls can be estimated.Key words: ductility, displacements, reinforced concrete, seismic design, stiffness, structural walls.

Extreme Modal Combinations for Pushover Analysis of RC Buildings

2013 ◽  
Vol 553 ◽  
pp. 117-124
Author(s):  
Ante Mihanović ◽  
Boris Trogrlić ◽  
Ivan Balić
Keyword(s):  
Limit State ◽  
Pushover Analysis ◽  
Mode Shapes ◽  
Eurocode 8 ◽  
Elastic Model ◽  
Seismic Action ◽  
Target Displacement ◽  
Ground Acceleration ◽  
Higher Modes ◽  
Practical Procedure

The pushover method is a practical procedure for comprehensive nonlinear analysis of structures subjected to seismic action. Application of this method, in accordance with the Eurocode 8 rules and due to engineering simplicity, favours application utilizing the first mode. The aim of the presented research in this paper was to find the influence of multi modal combinations in assessing the bearing capacity of reinforced concrete (RC) frames and walls. This paper presents a procedure in which the most extreme state is defined by the lowest ground acceleration caused by a predetermined shape of an elastic spectrum. The extreme bearing value is obtained by the envelope principle. Mode shapes and period sizes are determined on a linear elastic model while the limit state of the load bearing system is evaluated in a nonlinear state of structures. Results of the analysis show that influences of higher modes are significantly higher and that the safety/reliability, indicated by the criteria for the target displacement, in accordance with Eurocode 8 (Annex B), is not achieved. Inclusion of higher modes, in some presented examples, decreases the peak ground acceleration by more than two times, which is significantly less favourable than the target displacement criteria.

Full-scale physical testing of a buried reinforced concrete pipe under axle load

2014 ◽  
Vol 51 (4) ◽  
pp. 394-408 ◽  
Author(s):  
G.R. Lay ◽  
R.W.I. Brachman
Keyword(s):  
Reinforced Concrete ◽  
Soil Cover ◽  
Limit State ◽  
Structural Response ◽  
Bending Moment ◽  
Full Scale ◽  
Surface Load ◽  
Burial Depth ◽  
Concrete Pipe ◽  
Physical Testing

The structural response of a 600 mm inner diameter reinforced concrete pipe buried in a dense, well-graded sand and gravel soil and subjected to surface load from a single design truck axle with 0.3, 0.6, and 0.9 m of soil cover above the pipe crown is quantified using full-scale physical testing. The pipe did not crack at its minimum burial depth of 0.3 m under working CL-625 and CL-800 single-axle highway design loads as the largest tensile strains were only 50%–60% of those at the onset of cracking. Application of the fully factored CL-625 single-axle load at a burial depth of 0.3 m resulted in a tensile crack and a maximum circumferential bending moment of 6 kN·m/m; however, no limit state was reached as the crack width was around one-half the value used to define pipe serviceability and the maximum moment was around 70% of the theoretical ultimate capacity. The decrease in pipe demand from surface load with increasing soil cover is also quantified. At 400 kN of single-axle force, the crown moment decreased to 65% and 35% of the value at 0.3 m burial when the depth of soil cover was increased to 0.6 and 0.9 m, respectively.

scholarly journals Methods for conceptual and preliminary seismic design of buildings with steel structure

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Tiago Ribeiro ◽  
Ana Sousa
Keyword(s):  
Seismic Design ◽  
Steel Structure ◽  
Steel Structures ◽  
Eurocode 8 ◽  
Seismic Action ◽  
The European Union ◽  
Design Standards ◽  
Design Guide ◽  
Current Context ◽  
Earthquake Effects

Throughout the last two decades, seismic design standards evolved to ever more comprehensive and detailed prescriptions, stressing out the need for design methods that deal with earthquake effects not as actions, but as a design philosophy. The Eurocode 8 adoption as national law throughout the European Union countries and informally in many parts of Africa, Asia and Latin America is the pretext for the current study. It aims to provide some guidance to the seismic design of steel structures as well as to the Eurocode 8 implementation by the designers.Some lines on the preliminary design of structural systems were written based on several real cases of structures designed taking into account the seismic action. Such a content is, usually, relevant in any design guide, given its value in enhancing the design technical and economical content. However, it is now of utter significance at the current context as an essential tool to facilitate the safety checking of several code requirements.Some of the Eurocode 8 prescriptions are then decoded, explained and justified based on the supportive bibliography. The information is subsequently ordered as a design guide, where some procedures are proposed to cope with the code interrelated prescriptions and one structural solution is proposed in order to overcome a design challenge while complying with the code.One last but not less relevant addressed issue is the fact that some Eurocode 8 prescriptions may be reviewed, in the eyes of a designer, given its practical outcome. Such issues are identified, explained and some slight code adjustments are suggested.

scholarly journals Comparative analysis of normative provisions for seismic design and detailing of reinforced concrete structures

2019 ◽  
Vol 12 (5) ◽  
pp. 1220-1247
Author(s):  
R. A. RODRIGUES ◽  
C. E. N. MAZZILLI ◽  
T. N. BITTENCOURT
Keyword(s):  
Reinforced Concrete ◽  
Comparative Analysis ◽  
Seismic Design ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Concrete Structures ◽  
Eurocode 8 ◽  
Reinforced Concrete Structures ◽  
Seismic Design Of Structures

Abstract The main objective of this work is to carry out a comparative analysis between the methods and provisions of the Brazilian code ABNT NBR 15421:2006 and those of the ASCE/SEI 7 and the Eurocode 8, on the seismic design of structures. The similarities and differences between these standards, as far as the application of the Equivalent Lateral Forces method (ELFM) and the Response Spectrum method (RSM) are concerned, will be addressed. The responses will be evaluated for a case study that will be modelled by the SCIA Engineer 17 software. This paper also presents some comments on the detailing of reinforced concrete structures to ensure a good performance under seismic loading, allowing for a more favourable interpretation of the seismic analysis results.

scholarly journals Relationship between Corrosion of Reinforcement and Surface Cracking Width in Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jian Cao ◽  
Liangfang Liu ◽  
Shangchuan Zhao
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Surface Crack ◽  
Crack Width ◽  
Limit State ◽  
Steel Corrosion ◽  
Reduction Factor ◽  
Surface Cracking ◽  
Stiffness Reduction ◽  
Experimental Values

The durability of structure cannot be guaranteed when a corrosion expansion crack reaches the surface of the reinforced concrete member. In this paper, firstly, based on the existing theoretical model of steel corrosion degree, the calculation process of the model and the determination of the relevant parameters in the model were analyzed and discussed. Secondly, the stiffness reduction factor of concrete in the model was calculated according to the existing experimental data, and the engineering formula of the steel corrosion degree was established, which was related to the surface crack width of reinforced concrete. Moreover, the experiments of steel bar corrosion were carried out with different components of surface crack width, in which the parameters of the bar diameter, concrete protection layer thickness, and water-cement ratio were taken into consideration. The experimental phenomena and results were further analyzed and discussed. Finally, comparing with the experimental data, the engineering formula presented in the paper was validated. The results show that the calculated values by the engineering formula are in better agreement with the experimental values than those by the existing model, which provide a theoretical basis for further study on the durability limit state of the structure.

scholarly journals Update of the P100-1 Concrete Provisions

2014 ◽  
Vol 10 (3) ◽  
pp. 36-47 ◽  
Author(s):  
Viorel Popa
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
General Information ◽  
Seismic Action ◽  
Structural Components ◽  
Design Code ◽  
Revision Process ◽  
Seismic Design Code ◽  
Steel Composite ◽  
Composite Wood

Abstract In an effort to improve the harmonization of the Romanian design codes with the Eurocodes, the revision of the Seismic Design Code, P100-1, started in April 2010 and ended in September 2013. The main issues addressed during the revision process are presented in this paper. They include re-outlining the fundamental requirements for seismic design, revision of the seismic action, improvement of the specific provisions for the design of reinforced concrete, steel, composite, wood and masonry structures and non-structural components. This paper focuses on the specific provisions for reinforced concrete structures but general information about the fundamental requirements and the seismic action are presented as well.

Performance-Based Seismic Design of Reinforced Concrete Beam-Column Joints

2011 ◽  
Vol 255-260 ◽  
pp. 2500-2504
Author(s):  
Bin Wei ◽  
Zhong Guo Guan ◽  
Jian Zhong Li
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Concrete Beam ◽  
Limit State ◽  
Reinforced Concrete Beam ◽  
Rational Analysis ◽  
Limit States ◽  
Stress Strain ◽  
Performance Based Seismic Design ◽  
Relationship Of

A performance-based seismic design approach for reinforced concrete beam-column joints has been proposed in this paper. Instead of adopting empirical analysis such as in ACI 318M-08 building code, the proposed approach is based on rational analysis of the stress-strain state of the joint. Two limit states are considered in the design: serviceability limit state and life safety limit state. Performances of the joint at these two levels are determined respectively, with due considerations of capacity design philosophy and post-earthquake repair requirements. Then stress/strain analyses of the joint panel using the Mohr circle in conjunction with the softened stress-strain relationship of concrete are adopted simultaneously to design the joint to achieve the predetermined performance level. Effectiveness of proposed method are validated by using the model to interpret the behaviors of joints observed in previous experiments.

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