Structural Strengthening

B-267/268, North Ex Mall, Sector 9, Rohini, New Delhi - 110085 Tel No: +91-11-47068151/52/56 Email: info@epa-infrastructure.com

EPA Infrastructure Pvt. Limited

Structural Strengthening

Structural strengthening, restoring and adding capacity is an integral part of today’s concrete repair industry. Structural strengthening may be required for increasing load capacity of beams, columns, walls, and/or slabs, seismic retrofitting, supporting additional live or dead loads not included in original design, to relieve stresses generated by design or construction errors, or to restore original load capacity to damaged structural elements.

Advanced Composite Material

Fiber reinforced polymer (FRP) composite systems are used to strengthen a wide variety of structures for flexure, shear, axial loads, and seismic upgrading. Both Glass FRP (GFRP) and Carob FRP (CFRP) are used in these applications with CFRP being used for most structural applications.

Fiber reinforced polymer (FRP) composites have been used for decades in aerospace and manufacturing applications where low weight, high tensile strength, and non-corrosive structural properties are required. In civil engineering applications, CFRP has proven to be extremely effective as externally bonded reinforcement. CFRP materials are successful because they exhibit low creep, and compared with steel, are thinner, lighter, and have 10 times the tensile strength.

Advantages

Quick completion time

Cost effective when compared with the remove and replace option

No additional dead load added to the structure

Minimal access to work area required

No heavy equipment is involved

Corrosion resistant system

No maintenance required

Structural Steel

Often structural or steel plates are added to concrete structures to allow them to carry additional loading. In most applications the steel plates are bonded to the concrete by means of epoxy adhesives, and in addition to bonding, it is a good practice to also bolt the steel plates to the concrete.

While this process is relatively labour and equipment intensive, there are many applications where the use of steel plates is the best alternative for structural strengthening. Typical applications for bonded steel strengthening are the ones where the use of advanced composite materials would be prohibitive due to their higher costs, and/or where traffic or other type of wear would damage a FRP type strengthening system.

Advantages

Low cost (as long as no special shape fabrication required)

Vandalism and wear resistant

Post-Tensioning Strengthening For strengthening pre-stressed concrete beams or

slabs, simple externally bonded strengthening systems may not be sufficient. In these situations the strengthening system may need to be tensioned to provide an active strengthening system and be able to enhance the load carrying capacity of the concrete structure in conjunction with the existing built-in pre-stressing system. In most cases the post-tensioning system is designed with the following external components: fixed anchorage system located towards each end of the beam/slab, and post-tensioning cable that tensioned between the two anchors then locked in a tensioned state. The tensioning cable can be regular high tensile multi-strand steel, rigid carbon fiber rod, or carbon fiber fabric. The post-tensioning cable can be bonded or un-bonded along its entire length. The end anchorage system can be made of either concrete that is doweled into the existing concrete, or could be manufactured of structural steel that is bolted to the structure.

Advantages

Increases load capacity of the structure to design specifications

Cost effective alternative to the only other option: remove and replace

Minimal construction time required

Requires minimal or no disruption to traffic/plant operation

Thank You

Thank You