# Cost Estimation of Structures in Commercial Buildings

## Cost Estimation of Structures in Commercial Buildings

Surinder Singh

Preference :

Approximate cost estimates for structural works are always needed for one reason or another at the initial design stage in the building construction industry, and the techniques generally used for their preparation are the percentage estimate method, the superficial or floor area method (also known as the square metre method) and the approximate quantities method.
A proper application of the first two methods requires an in-depth knowledge of historical cost information of completed buildings and of the effect of design parameters on the construction cost.
Information on constituent quantities of completed buildings is not readily available. Realistic estimates may thus require the engineer to work out different schemes so that the most economical one may be selected. It is time-consuming and unsystematic if this has to be done for every project. With these drawbacks in mind, the author has supplied the basic data and discussed, in relation to commercial buildings ranging from 5 to 50 storeys, the effect of different design parameters on quantities of constituents for common structural systems, namely the reinforced concrete beam and slab system, the flat slab and waffle slab systems, and the prestressed concrete beam and reinforced concrete slab system. This approach to constituent quantities will enable both students and professionals to develop estimates with ease, speed and accuracy.

A critical review of the previous work relating to structural design economics has indicated that the
investigations were either based on records of past completed projects or on first principles by analysis, design and computation of quantities. The former approach has a number of drawbacks and, in view of this, the author decided to follow the more scientific approach of analysis, design and computation of quantities for structures of varying heights and structural systems based on the latest British Standards and Codes.
The information on constituent quantities is presented in the form of charts and the effects of design
parameters such as column grid size, number of storeys, location of structural components, arrangement of beams, grades of concrete, etc. on the quantities of various constituents of concrete construction for different structural systems have been discussed. Using the charts presented, applications for comparative cost estimation to assess the effect of various design parameters, for approximate structural cost estimation of an overall project given its design features, for checking the estimates for structural works, for calculation of quantity index for structural works, and for various other building economics studies have been illustrated.

Content :
• Introduction
• Review of Previous Work
• Reinforced Concrete Beam and Slab System
• Flat Slab and Waffle Slab Systems
• Prestressed Concrete Beam and Reinforced Concrete Slab System
• Quantities/Cost - Observations, Trends and Variations
• Computer-Based Cost Model for Reinforced Concrete Beam and Slab System
• Case Studies for Comparison of Results
• Additional Data for Preliminary Cost Estimation