Steel Strengthening as a Solution of Reinforced Concrete Structures

Abstract

Errors in planning or construction due to insufficient design dimensions and/or insufficient reinforcing steel or damage to structural parts. This is due to aging of construction materials also Load increases due to higher live loads. The concrete structures must be Strengthen. This research discusses strengthening of reinforced concrete structures, (Columns, Beams, Foundations and Slabs) for a local building. This building is subjected to failure due to bad construction methods and the difference between the design detailing and the structural section for existing building. Based on the analysis results the following conclusions had been drawn: The capacity of the footings was checked for adequacy to carry the obtained footing loads under load combination 2 (Service Load). The results show that 30 of the 60 footing in the analyzed part of the building were inadequately sized by more than 30%. After re-designed of the foundations, the Pad Foundation enlarge to Raft foundation to meet the code requirements to make the building safe.

The results after re-design were to increase all the Internal Columns sections 250 x 600mm for (short, ground, first and second floor columns) to column section 550 x 900 with steel reinforcement ( 4 Ø 20mm + 8 Ø 12mm) by strengthening the columns with concrete jacket to increase the section capacity to carry the load.

And also to increase all the External Columns sections 300 x 600mm for (short, ground, first and second floor columns) to column section 450 x 900mm with steel reinforcement (4Ø20mm+5Ø12mm) by strengthening the columns with concrete jacket to increase the section capacity to carry the load.

The Slabs in the building (case study) were structurally analyzed under ultimate loads (load combination 1) using the three dimensional model. Reinforcement module and the needed reinforcements for the slab section were checked and the results indicate that the slab design for this building is adequate.