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OPTIMISATION OF COST OF RCC FRAME STRUCTURES. Santosh Kumar Former Sr. Vice President Reliance Infrastructure. Components of RCC Frame. Foundation system Column Beam Slab. Unit cost of an R.C.C Frame Structure is a function of:. Planning Analysis Design Selection of Materials
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OPTIMISATION OF COST OF RCC FRAME STRUCTURES Santosh Kumar Former Sr. Vice President Reliance Infrastructure
Components of RCC Frame • Foundation system • Column • Beam • Slab
Unit cost of an R.C.C Frame Structure is a function of: • Planning • Analysis • Design • Selection of Materials • Management
Factors Affecting The Cost • Safe bearing capacity and selection of foundation system. • No. of storey in the building and height of each individual storey. • Selection/ grade of materials and relative costs of concrete and steel. • Planning of column-beam framework.
Contd. • Seismic zone, type of soil, Importance factor and response of the structure to natural frequency of the earthquake. • Alternative methods adoptedfor analysis and design of structure. • Period of construction, resource management and the extent of automation.
Safe Bearing Capacity • Determination of SBC has a profound impact on the cost of foundation. • Several methods are prevalent in determining SBC. Often there are vast variations in the recommendations, depending upon the approach adopted by soil investigation consultant.
ALTERNATE FOUNDATION SYSTEMS • There shall always be several alternative foundation systems feasible for the given: • soil parameters (C, φ and Y) • Load from super-structure • SBC
Contd… • Isolated/ combined/ strip footings • Mini raft • Complete raft • A combination of above. • Pile foundation • Combination of pile and isolated footing. Selection of the most appropriate foundation system greatly affects the unit cost of RCC frame.
HEIGHT & NO. OF STOREY Unit cost is a function of : • Storey height • Number of storey • Grid size in X-Y plane • Column spacing • Grade of concrete & steel • Relative cost of materials • Live Load • Dead Load • Seismic load Each faactor requires critical assessment to optimise the unit cost of RCC frame.
DEAD LOAD Dead load primarily comprises of : • Bricks used as in-fills • Flooring materials • Water proofing system • Sizes of structural elements Substantial reduction can be achieved by adopting lighter materials, instead of conventional materials. Unit cost of RCC frame is profoundly affected by appropriate selection of materials.