by Harsh Pareek, Regional Sales Director, India and SAARC, Trimble Solutions
Concrete is the most widely used construction material in India. It is the de-facto construction material of choice for most types of projects: from independent houses to tall residential complexes, from schools and hospitals to bridges and even roads now! In 2017, Union Transport Minister Nitin Gadkari announced a renewed push for converting all roads across to concrete in order to improve their stability and durability.
There are several reasons for such widespread adoption of concrete for construction, as compared to steel for example. Concrete is cheaper and more flexible as a construction material than steel. It is fire resistant and also highly durable. In certain cases, and conditions, concrete can be much more forgiving for contractors when there are detailing or modelling errors. Steel on the other hand requires high degree of precision and accuracy while detailing and fabrication.
However, concrete construction is not without its own set of problems and challenges. Traditional methods and workflows of concrete construction can be enormously inefficient, leading to project delays and cost escalations. Our internal analysis shows that a whopping 90% of all construction projects run late, 40% projects go over budget, and in every project, a minimum of 10% materials are wasted.
Even in normal times, this level of waste hits the contractors’ bottom line and also adds to the environmental degradation. In today’s times when the construction industry is grappling with an economic slowdown and reduced speed of work owing to social distancing norms, there is an urgent need for improving the efficiency of concrete construction processes.
Modern construction technologies, techniques and workflows are important enablers of efficiencies in all construction projects and concrete is no different. In fact, the global concrete industry’s shift from Cast-in-place (CIP) to Precast concrete is a noteworthy and influential trend that we believe will catch on in India soon.
Majority of Indian construction projects use Cast-in-Place (CIP) concrete, which means pouring, molding, and curing the concrete on the site of construction. CIP is conventional way of construction and comes with its own set of challenges.
The biggest concern with CIP is the significant volume of material wastage, which in turn pushes up the cost of construction. CIP construction is also a slow process, as freshly poured concrete needs a lot of time to take form and dry. In these times of the pandemic, CIP construction therefore carries huge risks for onsite workers as they have to spend extra days and weeks for construction in close proximity with one another.
Precast concrete construction not only solves all of these problems, but also improves significantly on the quality of construction. This technique is very similar to mass production of an automobile, where parts of the vehicle are manufactured in different factories and the final product is simply assembled and then shipped for use. Similarly, precast involves manufacturing of concrete elements such as walls or slabs in a tightly controlled factory environment, which are then transported to the project site and simply assembled there.
Compared with conventional cast-in-place (CIP) concrete systems, precast concrete is suitable for developing both conventional and modular structures of high quality. Precast is also extremely safe, for this technique has passed rigorous safety standards around the world for seismic and structural testing and fire safety.
Still, probably the biggest draw for precast construction is the reduction in overall costs; which can be as much as 15% of an overall project cost. This factor alone makes precast technology the chosen method of construction for India’s growing demands. The cost savings are a result of two unique and exclusive features of precast technology: improved speed of delivery and ease of installation.
In the first case, the factories that produce precast components follow world-class industrial methods based on mass production. As a result, they can produce a large volume of components in a short period of time, in turn enabling construction of more buildings in a relatively shorter time. This corresponds to a much lower total cost of construction and ownership of a building, as compared to one constructed using CIP or cast-in-situ concrete.
This is why we have seen a rapid increase in precast concrete-based construction in recent months and years. The benefits are compelling enough: precast concrete not only saves time, it also circumvents labour shortage and ensures a high-quality finished product with minimum wastage.
Constructible Models for efficient concrete construction
Similar to precast, modern technologies and workflows help improve the efficiency of concrete construction dramatically. Use of Building Information Modelling (BIM) for example leads to creation of highly accurate and information rich 3D models of a planned building or structure, which can then be used by an advanced software to estimate precise pour quantities and manage the pours optimally.
Tekla Structures, Trimble’s flagship modelling software for the construction industry offers Constructible 3D BIM right out of the box for concrete contractors and precast concrete producers. These models are highly constructible and are purpose-built for the needs of concrete construction. As a case in point, Tekla creates 3D models of pour information management, plan placement, quantify document formwork with intelligent, automated tools. It also coordinates adaptive and constructible reinforcement for any structure regardless of its complexity.
An important feature of Tekla Structures is an automated design-to-fabrication workflow. A model-based workflow not only minimizes costly surprises and waste, but also improves efficiency and quality. It further ensures that the correct, error-free elements are delivered at the right place and on time.
Model-based workflows even help with streamlined project planning and execution. They allow project stakeholders to keep track of the progress and keep all parties of the supply chain well informed at all stages of the project. Utilizing the status information in the model is in fact a clear and effective way to coordinate the project and ensure its progress according to the predetermined schedule.
Lessons from Global Leaders
When Barton Malow, a leading US construction services company with annual revenues exceeding $1 billion, started using Tekla for rebar detailing and fabrication, it noticed impressive efficiency gains upwards of 15 percent in less than a year. The software allows Barton Malow to reuse the models that other project parties create and simply add concrete and rebar.
Barton Marlow’s team was also able to share their models with engineers and trades, and combine various models for a complete view, taking advantage of the software’s ability to support multiple file formats. The model is not just a tool for drawings and coordination though. To gain the full potential of the software, Barton Malow tied the model to their fabrication software, Shear97.
“We were able to model bars, create drawings and send all the information directly to our fabrication system,” said Matt Hedke, Barton Malow’s Resteel Fabrication Manager. “I predict that we will see our efficiency gains increase even more as we become more proficient with Tekla.”
Concrete contractor Wayne Brothers first began looking at 3D Modeling software as a way to reduce risk and minimise waste. A good 3D model would not only allow them to notice concrete and rebar details that are just not visible on 2D drawings, but also identify potential issues such as omission and errors in design. But when they went with Tekla, they realised the software’s ability to improve their response times and efficiencies.
For Wayne Brothers, it is not unusual to win a contract and then be asked to be on the job site ready to go within just two to three weeks. Such agility requires getting a vendor on-board to detail the rebar, have it approved by the engineer, and get the rebar cut and delivered to the job site. With the traditional preplanning and submittal for approval process using 2D drawings, it’s virtually impossible to move that quickly and be accurate because it takes longer to detail and review the rebar.
Under Tekla and their new modelling process, Wayne Brothers team is able to create a model in preconstruction with concrete objects as part of their estimate to the client. When they win the project, they send the concrete model to the rebar vendor to add the rebar detail. When the client submits a drawing change, Wayne Brothers and the rebar vendor can update the model within in a few hours.
“With Tekla, we’ve reduced the time from the award to the first rebar submittal by 50 percent, allowing us to meet the most demanding schedules. This piece of software simply lets us be more successful in this highly competitive concrete market,” said Daniel Wayne, Wayne Brothers’ Director of Technology. “This gives us a clear competitive edge because we can respond quicker with more accuracy and provide a higher level of support to our clients.”
Evolving for the future
For progressive Indian concrete contractors and construction companies, adopting and embracing modern innovations in construction techniques, such as precast; and technologies, like constructible BIM; will prove to be critical enablers of success in this coronavirus-afflicted world. As several global construction leaders have demonstrated, these methods and technologies have convincingly proved their value in boosting construction process efficiencies and productivity along with enhancing workplace safety. These benefits are just too significant to ignore in today’s day and age.