Analysis of Post-Tensioned Flat Slabs, Conventional Slabs, and Flat Slabs using Etabs Software

Abstract

The modern-day submit-tensioning method is especially well-known because of its practicality; so, we will design the maximum safe and economical construction using this method. Every time we are planning the application of this technique, we must include more protective measures for slabs\' shear and deflection criteria. The rewards of submit stressing and especially of submit-tensioning are only to be acknowledged in any growing united state of America like our u.s.a. India. An enterprise is created to review the charge viability, durability, first-rate, maintainability of set up-Tensioned diploma piece frames as for built-up stage bite framework inside the examination. The reason for this new exam paper is improvement innovation problems in India and discovery of relevant causes, seriousness, affects to cover changes. Exploration must pave the way for improvement project strategy changes and reduce social and hierarchical adjustments in companies to boost advantage, care for warriors, and manipulate project to limit value and timetable crush. Classic slab, flat slab, and publish-tensioned flat slab comparisons are the topic of this thesis. In these studies, traditional slab, flat slab, and post-tensioned flat slab for G+10 storey structure with unique span length were compared. This slab was analyzed and designed using ETABS.

Introduction

Overview

The concept of pre-stressed concrete—concrete with internal compressive forces to counteract tensile stresses—originated in the U.S. in 1886 and was significantly advanced by French engineer Eugene Freyssinet in the 1930s. This technique prevents cracking and enhances the structural efficiency of concrete members, especially in slabs and pavements. Key historical developments include:

• Introduction of pre-stress using tensioned wires (1888, Dohring, Germany)

• Recognition of stress losses due to concrete shrinkage (Koenen and Steiner, early 1900s)

• Use of unbonded tendons (Dischinger, 1928)

• Freyssinet’s innovations in high-tensile steel wire stressing and vibration methods for high-strength concrete (1928–1933)

Pre-Stressing Techniques

Two main methods are used:

• Pre-tensioning: Tendons are stressed before concrete is cast.

• Post-tensioning: Tendons are stressed after concrete has hardened.

These are widely used in modern slab construction, including flat slabs and crack-free applications such as tennis courts.

Methodology

A G+10 multi-storey building is analyzed using ETABS software with three different slab systems:

1. Conventional slab

2. Flat slab

3. Post-tensioned (PT) flat slab

Model Details:

• Base height: 4 m; top storey: 4.6 m; intermediate storeys: 3.6 m

• Building footprint: 32.25 m × 19.55 m

• Concrete grade: M35 for all components (beam, column, and slab)

Results & Discussion

1. Structural Analysis

Using ETABS, design and analysis of the three slab types were conducted, and key metrics compared:

• Column Moments

• Story Drift

• Bending Moments

2. Story Drift Comparison

• Post-tensioned flat slabs consistently show the lowest drift values, indicating better structural stability.

• Flat slabs and normal slabs show higher drift, especially in higher stories.

3. Moment Comparison

• Flat slab max moment: 3726.98 kN-m

• Post-tensioned flat slab max moment: Reduced to 3034.86 kN-m

• The reduction highlights improved efficiency and material saving in PT slabs.

4. Moment Distribution Visualization

• Yellow areas in the diagrams indicate positive bending (steel required above the neutral axis).

• Red areas show negative bending (steel required below the neutral axis).

• This helps optimize reinforcement placement.

Conclusion

A. Conclusion We reduced steel and concrete quantities, therefore post-tensioning flat slab was cheaper than flat slab and standard slab. PT slabs use 41% and 29% less concrete than flat slabs. It found that post-tensioning flat slabs use less steel than normal slabs. Pt slab steel reduction is 85% of standard slab. Post-tensioned flat slab systems have much higher floor-to-floor height. Post-tensioned flat slab construction allows for faster formwork removal if a floor takes less time to build. Post-tensioned flat slabs are cheaper to produce since the floor construction takes less time and labor. Flat slabs deform more than post-tensioned slabs. As shown, post-tensioned flat slabs can be used for longer spans, thus future research can investigate slabs with varying thicknesses and column sizes. The moment of slab in post tension is less than that of a flat slab. B. Future Scope All above, we can grasp post tensioning slab is much more inexpensive for longer span rather than normal slab and traditional flat slab and it is extremely useful in longer span. We can increase the span and study the slab with variable thickness and column size in future research.

References

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Copyright

Copyright © 2025 Manoj Kumar Ahirwar, Murlidhar Chourasia. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.