Flat-Slab building is very popular from the aesthetic and architectural point of view. From functional aspect a flat-slab building is more efficient than a R.C. frame building. So, construction of Flat-Slab building is increasing also in high seismic zone. Sometimes international building codes remain silent about the seismic response of flat slab buildings. In this paper the response of Flat-Slab building and a normal symmetric R.C. frame building of same dimension have been studied for varying seismic intensities. Static, Response Spectrum, Pushover, and Time history analysis have been performed to assess the performance of the two buildings. The costs of construction for these two buildings have also been compared. An extensive study on lumped plasticity model as per FEMA 356 with varying position of plastic hinge and its effect on pushover curve has also discussed in the paper. The paper also comments on the plastic hinge pattern.
Table of Contents
Chapter-1
INTRODUCTION
1. General
1.1 Objective of Study
1.2 Organization of the dissertation
Chapter-2
LITERATURE REVIEW
Chapter-3
MODELLING OF FLAT SLAB BUILDINGS
3.1.General
3.2 Types of flat slab
3.3 Different components of flat slab
3.3.1 Use of column head
3.3.2 Use of drop panel
3.4 Advantages of flat slab
3.4.1 Flexibility in room Layout
3.4.2 Prefabricated welded mesh
3.4.3 Buildable scores
3.5 Behavior of flat slab building during earthquake
3.6 Modeling of flat slab
3.6.1 Finite element approach
3.6.2 Equivalent frame method
3.6.3 Modified equivalent frame method
3.6.4 Extended beam- width procedure
3.6.5 Extended equivalent column method
3.6.6 Extended equivalent slab method
Chapter-4
SEISMIC SAFETY OF FLAT SLAB BUILDING
4.1 Building data
4.2 Comparison of cost
4.3 Materials of construction
Chapter-5
METHODS OF ANALYSIS
5.1 Static analysis
5.2 Frequency analysis
5.3 Response spectra
5.4 Design spectra
5.5 Push over analysis
5.6 Time history
Chapter-6
RESULTS AND DISCUSSION
6.1 Static analysis and validation of model
6.2 Frequency analysis
6.3 Response spectra
6.4 Pushover Analysis
6.4.1 Modeling Approach
6.4.2 Modeling of Frame
6.4.3 Material nonlinearity
6.4.4 Geometric nonlinearity
6.4.5 Plastic deformation curve
Chapter-7
STABILITY OF FLAT SLAB- A CASE STUDY
7.1 Structural configuration
Fig-7.2 FEM model of city mall building
7.2 Loads on the building
7.2.1 Earthquake Load (EL)
7.3 Results and discussions
Chapter-8
CONCLUSIONS
PUBLICATIONS
Research Objectives and Thematic Focus
This dissertation aims to evaluate the seismic performance of flat slab buildings compared to conventional beam-column structures. The primary research goal is to assess the structural feasibility and stability of flat slab systems in high seismic zones, addressing the challenges associated with their inherent lack of lateral stiffness and vulnerability to punching shear failures.
- Performance estimation of flat slab buildings under seismic loads.
- Comparative analysis of static and dynamic behavior using various building codes.
- Investigation of failure patterns through non-linear pushover and time history analysis.
- Evaluation of cost-effectiveness and structural improvements using drop panels and camouflage beams.
Excerpt from the Book
3.1.General
Flat slab are preferential by both architects and clients because of their aesthetic and economic advantages. Though this form of reinforced concrete construction gives several advantages over frame structure, they also present some disadvantages because of brittle punching failure and large deformation. Many researches propose that flat slab should be designed to resist only gravity loads when used in higher seismic zones and lateral loads should be carried by lateral resist in system.
This study is inclined towards the seismic response of flat plate-braced frame system or stud rail. Braces are used as structure elements and they do resist lateral forces with substantial structural action and stud rail resist punching shear.
Slab-column connections are the first point of yielding in case of building without braces or stud rail. The shear capacity of this connection reduces drastically in the presence of lateral loading and hence, in such type of buildings should be carefully designed.
Flat slab can be supported by column and by a column capital and drop panel. The flat slab system has been adopted in many buildings constructed recently due to the advantage of reduced floor heights to meet the economical and architecture demands. The design of flat slabs is typically governed by the punching shear strength at failure.
Chapter Summaries
INTRODUCTION: Outlines the shift in construction practices towards flat slab systems and defines the research objectives regarding seismic safety and performance evaluation.
LITERATURE REVIEW: Provides a summary of historical research regarding the seismic response of flat slabs, including key contributions on modeling methods and punching shear reinforcement.
MODELLING OF FLAT SLAB BUILDINGS: Discusses the structural components of flat slab systems and details various modeling techniques used to simulate their behavior.
SEISMIC SAFETY OF FLAT SLAB BUILDING: Presents the numerical data and structural models used to analyze the seismic response and costs of various flat slab configurations.
METHODS OF ANALYSIS: Explains the mathematical and computational approaches, including static, frequency, response spectra, and non-linear pushover analyses employed in this study.
RESULTS AND DISCUSSION: Details the findings from the various analyses, covering stress distributions, deflections, and the evaluation of failure patterns.
STABILITY OF FLAT SLAB- A CASE STUDY: Applies the developed methodologies to a specific shopping mall case study to test performance in high seismic zones.
CONCLUSIONS: Summarizes the key findings, confirming that while flat slab systems offer architectural benefits, they require careful structural design for stability in seismic regions.
Keywords
Flat Slab, Seismic Safety, Punching Shear, Pushover Analysis, Time History Analysis, Lateral Deformation, Structural Stability, Finite Element Method, Equivalent Frame Method, Drop Panel, Camouflage Beam, Building Codes, Earthquake Resistance, Ductility, Reinforced Concrete.
Frequently Asked Questions
What is the core focus of this research?
The research focuses on the seismic performance and stability of reinforced concrete flat slab buildings compared to conventional beam-column structures, specifically in high seismic zones.
What are the central thematic fields covered in the work?
The study covers structural modeling, punching shear strength, seismic response analysis, cost-benefit comparisons, and the effect of structural modifications like drop panels on building stability.
What is the primary objective of this dissertation?
The main objective is to verify the feasibility of using flat slab structures in high seismic zones and to identify strategies to mitigate their vulnerability to brittle failure and large lateral deformations.
Which scientific methods are utilized to evaluate the structures?
The study employs a multi-faceted analysis approach including linear static analysis, frequency analysis, response spectrum analysis, non-linear static pushover analysis, and non-linear time history analysis using SAP 2000 software.
What topics are discussed in the main part of the dissertation?
The main body covers the modeling techniques for flat slabs, the assessment of seismic safety through numerical examples, a comparative analysis of different building codes, and a practical case study of a shopping mall.
Which keywords best characterize this work?
Key terms include Flat Slab, Seismic Safety, Punching Shear, Pushover Analysis, Lateral Deformation, and Finite Element Method.
Why is the flat slab-column junction considered critical?
It is the first point of yielding in buildings without braces. Lateral loading drastically reduces the shear capacity of this connection, making it highly susceptible to brittle punching failure during an earthquake.
How does the inclusion of drop panels affect structural performance?
Drop panels significantly enhance the punching shear strength of the flat slab and improve the overall ductility of the building, which is essential for earthquake resistance.
What is the role of the 'camouflage beam' in this study?
The camouflage beam is proposed as a viable alternative for flat slab buildings, as it allows for better performance than basic flat slab configurations when combined with increased slab thickness, even outperforming conventional designs in some cases.
- Citar trabajo
- Mohd Rizwan Bhina (Autor), Dr. D. K. Paul (Autor), 2013, Assessment of R. C. Flat Slab Building, Múnich, GRIN Verlag, https://www.grin.com/document/232202
