Over the past decade, the infrastructure industry has undergone significant changes thanks to the emergence of new technologies such as composite buildings. These structures incorporate steel frameworks encased in concrete and flooring solutions like Speedfloor, pre-cast slabs, and hollow core slabs. These buildings are considered eco-friendly or green due to several factors that help reduce pollution and conserve natural resources.

To be considered a sustainable construction, a green building must meet environmental standards throughout its entire life cycle, including its design, construction, and use. Green building design aims to balance the built and natural environments, utilising natural materials and low-energy, renewable resources.

Green building is not a specific construction method but a combination of techniques, materials, and integrated technologies to improve environmental performance. Steel is arguably the most sustainable of the major structural materials, offering numerous benefits realised whenever steel is used.

1. Weight - Steel's lightweight characteristic makes it easy to transport over land and lift with a crane, reducing the fuel consumption required to transport it to the construction site. This also simplifies dismantling and relocating buildings, as the low weight facilitates moving and rebuilding structures.

As a result, steel is a highly desirable building material for structures with extra land available for expansion due to its added mobility and versatility.

 2. Sustainability - As the demand for eco-friendly buildings grows, steel is expected to become a more attractive material for construction projects. This is due to its recyclability, as it can be easily repurposed rather than permanently disposed of.

For example, old buildings or temporary supports made from steel can be recycled and used in new projects as needed. Recovered undamaged steel components can be reused in other projects, eliminating the need to melt down and recast the alloy to create a new part. In cases where a building is being demolished and rebuilt, existing steel parts can be stripped out and repurposed to save costs. These parts can be stored for future projects or sold to another company as components or raw alloy if sold back to a steel fabrication company.

3. Strength - The high strength-to-weight ratio of steel means that less material is required for a single support or beam, resulting in lower material costs and improved sustainability. Steel is also highly resistant to physical impacts and forces, providing a high level of safety for building occupants without deteriorating or needing to be replaced afterward.

This strength can be maintained through the structure's design, rather than the amount of steel used. Additionally, alloy steel's natural fire and rust resistance makes it a suitable choice for exterior structures such as fire escapes or balcony supports. It could also be considered for use as external walls to contain insulating materials.

4. Price – Modern building regulations are highly prescriptive when it comes to construction efficiency, often resulting in reduced maintenance and material costs in the long term. While concrete is more price stable compared to steel, the costs of repairing and reinforcing a concrete beam or pillar usually make steel more cost-effective over the entire lifespan of a building. Steel is a fully recyclable material that maintains its inherent properties. Therefore, a significant amount of recovered steel can significantly reduce the cost of constructing a new structure.

Composite construction

 Composite construction, which involves using steel structures encased in concrete, results in less concrete than conventional RCC (reinforced cement concrete) construction. This reduction in concrete usage reduces dust and air pollution, common byproducts of traditional RCC construction practices.

 Moreover, composite construction's lower concrete consumption reduces the use of aggregates and sand. This is significant, as the depletion of natural stone quarries and river beds is a major environmental concern. Additionally, composite construction requires less water, a scarce resource and a significant environmental concern.

 Composite construction also involves less material movement, which results in less traffic and further helps to reduce air pollution. Additionally, it addresses current environmental concerns such as sustainable development and environmental preservation and has demonstrated aesthetic and technical superiority over its conventional RCC counterparts.

 Composite construction leverages the strengths of both concrete and steel. Steel provides the necessary strength and agility, while concrete can be molded into the desired shape to create a highly efficient and lightweight, visually appealing structure. Overall, composite construction maximises the benefits of all materials and creates superior structures in form and function.

 Utilising high-quality steel, such as E550 and E450, in composite construction offers numerous benefits, such as allowing for smaller column sizes, resulting in increased carpet area, shallower beams leading to higher clear floor-to-floor heights, reducing weight on the foundation, and reducing weight overall, which in turn leads to lower seismic forces. This gives architects more freedom to experiment with building designs without compromising its integrity.

 Incorporating high-grade structural steel in composite construction can significantly decrease the material needed per square foot. Using composite columns, decking, and beams makes it possible to construct tall buildings efficiently. Construction activities can be carried out simultaneously in a vertical spread with several trades working concurrently.For example, one group may erect steel beams and columns for the top storeys while another is fixing metal decking for the floors below. As we move down the building, other groups may be tying reinforcing bars in cages, fixing formwork, pouring concrete into column molds, and concreting floors. Additionally, the weight of composite structures using high-grade steel is lower than traditional RCC structures, resulting in more cost-effective foundations.

 In conclusion, steel plays a significant role in sustainable construction and green building design. Its lightweight, strength, and recyclability make it an attractive proposition for eco-friendly buildings. Composite construction, which combines steel and concrete, further maximises the benefits of both materials and reduces pollution and resource depletion. Utilising high-grade structural steel in composite construction leads to more efficient construction, decreased material usage, and cost-effective foundations. As the demand for eco-friendly buildings grows, steel is expected to become an increasingly attractive and sustainable choice for construction projects.