Materially efficient structural floor systems for housing in India

Abstract

.In 2015, the government of India launched the "Housing for All by 2022" initiative to build 20 million units of affordable urban housing for lower income groups. Thus far, they have built fewer than two million units. In India, it is estimated that material costs can constitute 60 to 80% of the total cost of residential construction. Nonetheless, their construction mimics the materially inefficient practices of developed countries, practices developed to reduce labor over material costs. As a result, prismatic beams and flat slabs are frequently used despite their structural inefficiency. In its current state, the construction industry is resource intensive and unsustainable. The mounting use of steel-reinforced concrete structures in Indian cities has also garnered concern for the environmental costs of construction; construction accounts for 22% of India's carbon emissions.

The impact of structural systems on a building's embodied energy are immediately apparent: cement and steel are responsible for nearly 90% of a multistory concrete frame building's total embodied energy, and at least 50% of that is in the horizontally-spanning elements alone. With no end to construction in sight, new practices are needed to curb the environmental and economic costs of India's construction. This thesis explores the design of materially efficient floor systems that can reduce the economic and environmental costs of construction. Utilizing computational structural design, this thesis presents several strategies for the structural optimization of one-way concrete floor systems. Designed for the constraints of India, the structural elements are optimized to reduce the necessary volume of concrete and steel while resisting the same loads of an equivalent solid prismatic beam or slab.

While structural optimization for material efficiency is not a new practice, it is technically challenging and often reserved for large-scale and exclusive architectural projects. Conversely, this research applies these principles to common residential construction.