A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering School of Engineering and Technology

Thesis (M.Eng.)- Asian Institute of Technology, 1982

In this study, the attractiveness of various precast floor products, being manufactured in and around Bangkok, has been investigated from the viewpoints of efficiency and the investments required to establish such manufacturing units. The most attractive product has been identified and recommended for manufacture. The research was conducted in two parts; collection of data from precast concrete floor manufacturers and analysis of the data to determine the attractiveness of the different products. All these products were within the width range of 30 cm. to 65 cm. and not more than 4m.length. Sixteen manufacturers were contacted, out of which ten agreed to provide the required data. In addition, six of them gave permission to visit their factories. Efficiency of different products has been determined from the considerations of their costs, live load carrying capacity, dead load, depth of finished section, conditions for adoption and utilization of materials. Marks have been given to the three best products for each efficiency term. The sun of the marks for each products for all the efficiency terms has been the criteria for evaluating the most efficient product. The amounts of investment considered have been estimated based on current unit costs obtained from the INDUSTRIAL FINANCE CORPORATION OF THAILAND and their distributors. Product s in two systems, namely single element system and composite element system, have been considered in this study. Solid prestressed unit and ordinary reinforced single Tee have been found to be the two most efficient products respectively in the former system. For the latter system, the inverted Tee with brick tiles as infilling material was the most efficient followed by the inverted Tee with concrete blocks. However, from the investment considerations, the single Tee unit for the single element system and the inverted Tee unit with concrete blocks for the composite element system have been found to require the least investment. Comparison of the two systems has been made and the single Tee element has been found to possess more advantages than the inverted Tee with concrete blocks in terms of the amount of investment required, and efficiency. However, it should be aware that this type of products violates both the Minimum thickness specified by the Thai Industrial Standard for precast concrete floor elements, and minimum concrete covering of reinforcements required by the Engineering Institute of Thailand.