Detailed Report: Strengthening Old Church Road Bridge Analysis

This report provides recommendations for strengthening the Old Church Road bridge without demolishing it, focusing on two primary methods: steel plate strengthening and Fiber Reinforced Polymer (FRP) strengthening. The report details the advantages and processes of each method, noting the cost-effectiveness, availability, and ease of use of steel plates, as well as the superior strength-to-weight ratio of FRP. It emphasizes the importance of proper surface preparation for both methods to ensure effective bonding and composite action. The report concludes that while various materials are available for strengthening concrete structures, steel plate and FRP are the most preferred due to their beneficial features and widespread application in bridge rehabilitation projects.

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RECOMMENDATIONS TO STRENGTHEN THE OLD BRIDGE WITHOUT DEMOLISH THE
BRIDGE
A Research Paper on Bridge By
Student’s Name
Name of the Professor
Institutional Affiliation
City/State
Year/Month/Day

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INTRODUCTION
Strengthening of concrete bridges or structures in the field of structural maintenance is an
important task. Increasing the capacity of present operational elements is the main objective of
carrying out strengthening. This task is important since the bridges are not considered safe
resulting from increased load.
Methods
The two methods used in the strengthening of bridges include;
 Using steel plate
 Using Fiber reinforced polymer (Mazzolani, 2013)
a) Strengthening using Steel plate
The use of steel plate is one of the commonly used materials during strengthening. It is
necessary since it increases the shear and flexural capacity of the reinforced concrete beam.
Readily available, high tiredness strength, constant material properties, cheapness and easy to
work makes the steel plate popular when strengthening as depicted from the mentioned features.
In the year 1960, the investigation concerning the structures strengthened using this method
began and this type of method had been applied in strengthening both bridges and buildings in
numerous countries such as United Kingdom, Poland, France, Japan, Belgium, South Africa and
Switzerland (Reid, 2012).
The most commonly used method of plating is gluing steel plates to the tension faces of
beams whereby at this stage, the plate is at its utmost extremity from the area of compression
whereas the composite action is at its maximum. However, maintenance of composite action
between glue, concrete and the plate will be done until failure. This method efficiency depends
on bonding methods between existing beam, preparation of the surface and steel plate, therefore

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the preparation of the surface of the present beam and steel plate should be carried out efficiently
and also roughening of beam surface before placing the plates as explained by Adhikary et al
(2011).
The process of roughening is done using a mechanical grinding the laitance is removed then
brushing and cleaning the surface scrupulously using acetone. Acetone can also be used to clean
steel plates bonding faces after sandblasting. Epoxy adhesive is sited on the surface which is
rough after preparation of the surface has been done after which the steel plate is positioned on
top (Wipf, 2004).
b) Strengthening using Fiber reinforced polymer
This is a widely spread material for strengthening concrete structures and is a composite
material made of a polymer matrix. The fibers are usually armed, carbon or glass, while the
polymer includes vinyl ester or polyester A high strength to weight ratio, makes fiber reinforced
polymer (FRP) for strengthening to become an effective method. Compared to steel, the fiber
reinforced polymer had physical and mechanical properties superior to them, more so when
comparing fatigue and tensile strength (Rodger, 2014). Introduction of fiber reinforced polymer
composite materials was first carried out in the year 1940s which made US Air Force and Navy
use this material in the various application as a result of its exceptional strength to weight ratio.
Fig 1: Stress- strain diagrams for FRP (Reid, 2012)

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The world’s first highway bridge was built using fiber reinforced polymer in 1986 in
Germany, pedestrian bridges were built in 1996 and also more sustainable markets have
developed as a result of FRP materials in repairing and strengthening of structures made of
concrete. Numerous fiber reinforced polymer system are currently available commercially for
strengthening of concrete constructions externally (Milne, 2015). The arrangement of FRP is
shown in the picture shown below:
Fig 2: showing arrangements of FRP strips (Mazzolani, 2013)
Conclusion
Strengthening of reinforced concrete structures is one of the major task linked with
concrete structures maintenance and number of materials available in the market and used for
strengthening include steel plate, sprayed concrete, fiber reinforced polymer but in general, steel
plate and fiber reinforced polymer are the most preferred methods due to their features.

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Bibliography
Mazzolani, F., 2013. Refurbishment of Buildings and Bridges. London: Adventure Works Press.
Milne, D., 2015. Strengthening bridges using composite materials. Toledo: Cambridge University Press.
Reid, K., 2012. Steel Bridge Strengthening. Colorado: IEEE.
Rodger, D., 2014. Methods for Increasing Live Load Capacity. Michigan: IEEE.
Shinozuka, M., 2006. Structural Safety and Reliability. New York: China Publishing Company.
Wipf, T., 2004. Cost-effectiveness Practices for Off-system and Local Interest Bridges. s.l.:University of
Nairobi press.
Xanthakos, P., 2011. Bridge Strengthening and Rehabilitation. Perth: Wiley and Sons.