Design and Field Execution Process of Tee Beam Bridge by Using CSI Bridge Software

Abstract

This A Bridge is a structure providing passage over an obstacle without closing the way beneath. The required passage may be for a road, a railway, pedestrians, a canal or a pipeline. The obstacle to be crossed may be a river, a road, railway or a valley. Bridges range in length from a few meters to several kilometers. They are among the largest structures built by man. The demands on design and on materials are very high. A bridge must be strong enough to support its own weight as well as the weight of the people and vehicles that use it. The structure also must resist various natural occurrences, including earthquakes, strong winds, and changes in temperature. Most bridges have a concrete, steel, or wood framework and an asphalt or concrete road way on which people and vehicles travel. Our Kakinada has been a part of smart city programme; many renovations and development of new structures are being done. Under this programme many bridges are being reconstructed. As a part of this the one lane road bridge at Pratap Nagar, Kakinada is being upgraded into two lane road over bridge. This Project is an on-going work of two-lane road over bridge with a T-beam Reinforced Concrete Deck slab with 12m wide and 36m long having 5 spans with equal distribution of 7.2m length. In this project work we are going to design and analyse the two-lane road over bridge by using manual calculations and computational work with Bridge Software.

Introduction

Bridges are major structural systems designed to provide passage over obstacles such as rivers, roads, or valleys. They must support their own weight, carry traffic loads, and withstand environmental forces like wind, earthquakes, and temperature changes. Among bridge types, the T-beam bridge is commonly used for spans between 10–25 m, where the deck slab and longitudinal girders act together as monolithic T-beams. Reinforced concrete T-beam and slab decks are economical for medium spans and consist of longitudinal girders spaced 2–2.5 m apart, with cross girders placed every 4–5 m to provide stability.

Literature Review

Various studies have analyzed different bridge types using numerical and experimental methods:

• Mohseni et al. (2018) analyzed shear and reaction distribution in skew multi-cell box girder bridges using finite element modeling.

• Prajwal Raj et al. (2017) studied structural behavior of post-tensioned box girder bridges under IRC and AASHTO codes.

• Pengzhen Lu et al. (2012) developed and validated a spatial grillage model for analyzing T-frame bridges through analytical and experimental methods.

Methodology

The design process for a reinforced concrete T-beam bridge involves:

1. Determining formation levels, deck height, clearance, and foundation depth.

2. Preparing trial cross-sections and general arrangement drawings.

3. Designing the superstructure by:

   • Analyzing deck slabs.

   • Calculating dead and live load bending moments.

   • Performing transverse load distribution using Courbon’s method, grillage analysis, or FEM.

   • Designing the girders for bending, shear, and torsion.

Load distribution in the transverse direction can be modeled using rigid-frame methods, orthotropic plate theory, or grillage analysis. The grillage method is often preferred due to fewer simplifying assumptions.

Design Considerations

The bridge is designed following IRC:6-2000 specifications, considering:

• Dead loads and superimposed dead loads (wearing coat, crash barriers).

• Live loads (Class AA and Class A).

• Wind and seismic forces.

• Material specifications: M30 concrete and Fe415 reinforcement, with drainage and cover requirements.

Computational Analysis

Using CSI Bridge software and the Finite Element Method:

• The T-beam bridge (36 m long, 5 spans of 7.2 m each) is modeled with two external and two internal girders.

• Loads are applied according to IRC Class AA loading.

• Bending moments and shear forces are obtained for different spans.

Results

• The maximum bending moments occur in the external spans.

• In external girders, the maximum dead-load bending moment is:

  • 206.87 kN-m in outer spans (1 & 5)

  • 174.06 kN-m in inner spans (2–4)

• In internal girders, the maximum dead-load bending moment is:

  • 277.54 kN-m in outer spans

  • 235.28 kN-m in inner spans

Conclusion

1) The Analysis and Design of the T- Beam Bridge is safe and within the permissible limits. 2) The manual calculation of the bridge was done by Courbon’s Method and the computation work was done by CSI Bridge Software for validation. 3) The values obtained by the manual calculation and computation work was within the permissible limits and its safe. 4) The maximum Bending Moment and Shear Force are obtained in the End Spans when compared with intermediate spans of the bridge. 5) The Maximum Bending Moment of 1159.22 kN-m is obtained in Outer Girders and 1397.15 kN-m is obtained in Inner Girders by using Courbon’s method. 6) The Maximum Bending Moment of 1005.9 kN-m is obtained in Outer Girders and 1554.24 kN-m is obtained in Inner Girders by using CSI Bridge Software. 7) The Bending Moment obtained in the inner girders is more when compared with outer girders. 8) The values obtained by the CSI Bridge almost matches the results obtained by the Courbon’s method when subjected to Class AA Tracked loading. 9) Using finite element software (CSI Bridge) results are reduced by 13.2% as compared to Courbon’s Method for Bending moment and reduced by 11.39% for Shear Force in Outer Girder. 10) Using finite element software (CSI Bridge) results are increased by 10% as compared to Courbon’s Method for Bending moment and increased by 15.45% for Shear Force in Inner Girder. 11) The dimensions of the pier adopted are safe as the stresses are in safe permissible limits. 12) The values obtained by the finite element analysis give more economical structure compared to conventional method.

References

[1] S. IRC: 6-2000 I.R.C Standard specification and code of practice for Road Bridges, Section- II, Load and Stresses - ( Fourth Revision) [2] IRC: 21-2000 I.R.C Standard specification and code of practice for Road Bridges, Section- III, Cement Concrete (Plain and Reinforced) - (Third Revision) [3] “Design of Bridges” by Krishna Raju, Fourth Edition, Oxford and IBH Publishing Co. Pvt. Ltd., New Delhi. [4] “Essential of Bridge Engineering” by D.J. Victor, Sixth Edition, Oxford and IBH Publishing Co. Pvt. Ltd., New Delhi. [5] NPTEL: Reinforced concrete road Bridge Coarse (https://nptel.ac.in/courses/105105165/) [6] Soumya, Umadevi Et al, in (2018), Comparative Study of Courbon’s Method and Finite Element Method of RCC T–Beam and Deck Slab Bridge’. [7] Iman Mohseni, Et al, in (2018), Shear and reaction distribution in skew multicell Box- beam bridges. [8] Prajwal Raj, Et al, in (2017), structural behaviour of box girder bridge using “Csi Bridge 2015”. [9] N. D. Shah, and Dr. J. A. Desai, (2009), Importance of nonlinearity on cable stayed bridges. [10] N. Munirudrappa, Et al, in (1999), Dynamic analysis of continuous span highway bridge. [11] M.

Copyright

Copyright © 2025 Venkatesh Kumar Salapaka, K. Urmila Devi. 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.