Thumb Rules to achieve economy in RCC construction

The following are some of the rules of thumb which will be useful to the practicing engineers:-

Minimize floor-to-floor height: 

By minimizing the floor-to-floor height, the cost associated with mechanical services, stairs, exterior building cladding can be significantly reduced. The limiting factor will be deflection considerations.

Use repetitive formwork

The cost of formwork may be very high and is not given due consideration by the designers. The cost can be reduced when the framing system is used repetitively (10 or more times) on a structure.

Use standard column size 

This can be achieved by varying the amount of reinforcing steel and the concrete strength within the column. This will allow for a single column form and will minimize the number of variations to meet beam or slab forms.

Adopt uniform column layout

Uniform column layout results in simple formwork, which can be used repetitively from floor-to-floor. Similarly, regular shaped buildings will be more economical than irregularly shaped buildings with L- or T-shaped columns.

As far as possible, use the same depth for beams 

The saving in formwork and shoring costs will exceed any additional costs for concrete and reinforcing steel. This will also provide a uniform ceiling elevation and minimize mechanical service installation difficulties.

Use high strength concrete in columns 

The high strength may reduce the column size or the amount of reinforcing steel required for the column.

Use high early strength concrete

This will allow for earlier form stripping and will reduce total construction time.

Specify self-consolidating concrete 

Heavily reinforced columns and beams can be very congested with rebar, which prevents the proper placement of the concrete. SSC maximizes concrete flowability without harmful segregation and dramatically minimize honeycombing and air pockets.

Specify locally available materials 

The use of local aggregates and recycled materials in concrete makes it a 'green' product, which is requested by environmentally responsible owners.

Consider accidental loads for important buildings

for high-risk facilities such as public and commercial tall buildings, the accidental load such as bomb blast or high-velocity impact should be considered.

Use commonly available size of bars and spirals 

For a single structural member, the number of different sizes of bars should be kept to a minimum.

Use the largest bar size that satisfies the design considerations

Use larger size bars in columns and smaller size bars in slabs. Larger diameter bars reduce the number of bars that must be placed and minimize installation costs.

Eliminate bent bars where possible 

Bent bars increase fabrication costs and require greater storage area and sorting time on the job site.

Avoid congestion of steel 

Congestion of bars should be avoided, especially at beam-column joints, so that all reinforcements can be properly placed.