Sustainability is the avoidance of the depletion of natural resources so as to preserve an ecological balance in an environment. The principles of sustainability are the foundations of what the concept of sustainability represents. Sustainability is made up of three pillars: economic, social and environmental. These principles are also informally used as profit, people and planet. In the United States, the Environmental Protection Agency defines sustainable construction as “the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building’s life-cycle from siting to design, construction, operation, maintenance renovation and reconstruction.”
Around 40% of total energy consumption and greenhouse gas emissions are directly due to construction and operation of buildings. The best way to reduce this impact is the use of green building construction techniques. The cement industry is one of the two largest producers of carbon dioxide, releasing a potent greenhouse gas. According to Umberto Berardi in his book, Moving to Sustainable Buildings: Paths to Adopt Green Innovations in Developed countries, published in 2013, on page 22, “The building sector is receiving increasing attention in worldwide policies for sustainable development.” Buildings are now designed with plants around them and incorporating renewable energy use.
Sustainable architecture is the architecture that seeks to minimise the negative environmental impact of buildings by efficiency and moderation in the use of materials, energy, and development space and the ecosystem at large. Sustainable buildings use renewable energy and architects are now designing buildings using solar panels as roof materials and roads lights using solar energy. Sustainability is now the navigator of the ways civil engineering infrastructures are being constructed.
Designers are incorporating natural lighting and ventilation to reduce energy consumption in their modern design. Occupancy motion sensor light detects when occupants are in a room and goes off as soon as there is no occupant. This system will reduce energy consumption in buildings. In rooms with good daylight conditions, the motion sensors should have built-in light sensors. Natural fibre of different parts of plants, such as fibres extracted from the stem, leaf, or seed are being tested as reinforcing material in cementitious concrete.
Architects are now introducing the use of modern construction materials which are sustainability-compliant. They are experimenting with new materials and techniques that gave them greater freedom to create new forms. In 1903-1904 in Paris, Auguste Perret and Henri Sauvage began the use of reinforced concrete to build residential apartments/buildings which was previously only used for industrial buildings. The safety, stability and permanence of a building depend very largely upon the crust of the earth immediately beneath it, according to Ken Ward-Harvey in Fundamental Building Materials published in 2009. Sustainability in construction dictates that building foundations are designed according to the geology of the site and that constructions are not over-designed.
Lijuan Li in Advances in Building Materials published in 2011, on page 1 stated that “Currently, no one can doubt the importance of low carbon living and low carbon architecture. Numerous new materials and high technologies have been used in countries all over the world in the course of low carbon architecture’s development, some of which have had a favourable result, such as the London zero carbon emissions pavilion at the 2010 Shangai World Expo.” We all know that building materials are the basis of the construction industry; it costs a lot of energy. For building materials, walking the way of ecological building materials is necessary to adapt to the continued economic growth and meet the need for sustainable development.
Concrete is now being recycled and reused in the construction of buildings. Aluminium encasement filled with shredded waste materials is being used as walling materials for the construction of manufactured buildings. Balfour Beatty, the contractors that handled the Birmingham New Hospital project, appointed Premier Waste to manage all waste produced during the construction of the hospital. Balfour Beatty addressed waste reduction, recovery and management throughout the planning, design and construction stages of the project by working with subcontractors, suppliers and waste management contractors to develop and apply a range of approaches and mechanisms. From the inception of civil engineering construction, the issue of construction wastes and how to recycle them is discussed.
These waste management mechanisms included: designing out waste; establishing benchmarks and targets for material wastage and recycling; setting contractual requirements on subcontractors and suppliers for waste production, handling and management; establishing take-back schemes with suppliers for specific material streams and using closed-loop recycling in the construction of ‘green rooms’; using an on-site waste management contractor to coordinate the management of waste on-site, and using off-site waste management contractors to recover the segregated and mixed waste arising.
Civil engineering structures have a crucial role to play in the sustainable development of our environment in that it contributes about 40 per cent of energy-related carbon dioxide emissions annually. Any measure that can reduce or totally stop this emission will impact climate change and global warming mitigation. This is why all governments are laying serious foundations for the enthronement of sustainable civil engineering design and construction. Civil engineering infrastructure construction has a direct impact on the economic, social and environmental development of nations. A good example is the role of construction in the economic, environmental and social development of Chicago in the State of Illinois in the United States of America.
- Olufemi A. Oyedele, an estate surveyor and valuer, writes from Lagos
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