International Journal of Engineering Research and Reviews
ISSN 2348-697X (Online) Vol. 10, Issue 2, pp: (1-9), Month: April - June 2022, Available at: www.researchpublish.com
Behavior of Composite RC Slabs Made of New Slabs Added to Old Ones Using Shear Dowels Hesham A. Haggag1, Moustafa A. Osman2, Mohamed I. El- Shewy3 1
Professor, Civil Eng. Dept., Helwan University, Cairo, Egypt
2
Professor, Civil Eng. Dept., Helwan University, Cairo, Egypt
3
Structural Engineer, Master of Civil Eng. Student, Helwan University, Cairo, Egypt
Abstract: Structural Strengthening maybe required for structures to accommodate above the design values. Moreover, the change of the building use may require increase in structure element capacity. On the other hand, structural capacity upgrade may be needed in case of structural element deterioration. Concrete structures need to be strengthened for any of the following reasons: -
Load increase due to higher live loads, increased wheel loads, installations of heavy machinery, or vibrations.
- Damage to the structural parts due to aging of construction materials or fire damage, corrosion of the steel reinforcement and/or impact of vehicles. - Improvement in suitability for use due to limitation of deflections, reduction of stress in steel reinforcement and/or reduction of crack widths. -
Modification of structural system due to the elimination of walls/columns and/or openings cut through slabs.
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Errors in planning or construction due to insufficient design dimensions and/or insufficient reinforcing steel.
Keywords: Structural Strengthening, Composite RC Slabs, building, structural capacity, heavy machinery.
I. INTRODUCTION Recently, many types of strengthening slabs systems appeared using new technique of shear dowels. The use of shear dowels allows the optimization of cost and building period. The building types, which are using the slabs strengthening includes housing, hotels, shopping centers and office buildings …., etc. There are many methods to improve the behavior of slabs to withstand extra load, such as using the shear dowels to repair and increase the slabs thickness. Strengthening for slabs is very important and has many technology methods that leads to high-cost impact to meet our requirements, however, our study in this research is developing and demands for consumer simple method in order to meet the design requirements with less cost in reasonable time. The trial will be done for variable thickness of slabs by some evaluation of test results considering the study of the shear flow of the 2 connected slabs intersection surface. The problem of shear transfer in concrete structures arises when shearing forces are transmitted across a definite plane. The composite interface presents a potential weakness; they must be designed to have at least the same shear capacity of the adjoining parts. To achieve the composite action between old and new part, different types of shear connection between the two concrete surfaces may be used, such as rough surface connection, shear keyed connection, steel doweled shear connection and using of Epoxy binding materials.
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