The Crucial Need for Enhanced Risk Assessment in Accelerated Construction Methods

Introduction

The landscape of construction has been transformed by technological innovations, leading to accelerated methods that promise efficiency and productivity. Despite these advancements, the area of risk assessment has not kept pace, creating a significant imbalance. This gap exposes projects to potential failures and safety risks. As the industry embraces faster construction methodologies, the need for advanced risk assessment becomes not just beneficial, but crucial for the sustainability and success of any project.

The Present State of Construction Technology

Today's construction sites are a testament to technological evolution, boasting equipment, software, and tools designed for maximum efficiency and minimal effort. However, this shiny exterior belies a critical flaw: the methodologies for risk assessment have remained largely undeveloped, failing to evolve at a similar pace.

Identifying the Gap in Risk Analysis

While construction technology has significantly progressed, the approach to risk analysis has not kept pace, often focusing on a limited set of known risks and overlooking the complexities that arise from the varying construction methods, environmental, and geological conditions. This lack of comprehensive risk assessment is particularly concerning in modern construction projects, where rapid changes and the fast pace of work can amplify the consequences of unexpected problems. For instance, the collapse of an excavation pit can now occur within hours, a situation exacerbated by the rapid pace at which the excavation reaches critical depths, and the maximum ground loading is achieved, leaving no opportunity for observation and preventative measures due to safety protocols that keep personnel out of the hazard zone and operators focused away from observing ground deformations. To address this, it's proposed that construction methods include a protocol where, at every meter of excavation, a quick observation for ground deformation, seepage, or sweating is made, documented, and only then is excavation allowed to continue deeper. Additionally, all excavated pits should be regularly monitored by supervisory staff to provide early warnings of potential issues. Allocating 1-2% of equipment idle time for these safety measures is deemed acceptable to mitigate major risks.

Cases of Risk Assessment Failures

The construction industry is replete with examples where insufficient risk assessment led to project delays, increased costs, and safety hazards. A few recent cases are:

1. The sinkhole during tunneling for the M6 Tunnel, leading to the subsidence of a building, work stoppage, and incurring costs of thousands of cubic meters of concrete.

2. Ground subsidence in the Bow Bazar area of Kolkata during tunneling, leading to delays in the portion of the EW Metro.

3. The sinking of large barrages due to possible piping action, questioning the efficacy of construction and design.

4. The collapse of a tunnel, with personnel trapped for days and work stoppage.

5. Leakage and cracks through the tunnel despite thick concrete and waterproofing.

Do we think the designs were at fault? Probably not! Because more than the design factor, the dynamic factors evolving on-site every moment are more crucial, which becomes the trigger factor for any failure. Every design is based on a certain set of assumptions. In light of the above cases, a few of the probable and logical design assumptions for the above cases may be:

A. The ground in the near vicinity is stable, and when mechanical excavation is done, there is no possibility of the surrounding ground also caving in and will be removed.

B. If seepage is encountered, any speed of dewatering will not lead to ground loss due to artificial hydrostatic conditions which can trigger piping action.

C. There is no possibility of leakage through the secant piles, creating a condition for piping action.

D. The action of re-excavation to correct the tunnel profile will not have any impact on the overall ground stability.

E. In alluvial soil conditions, there is no possibility of differential settlement on either side of the construction joint, even if the dewatering locations are changed from time to time as the work progresses linearly.

Unless an in-depth risk assessment is done including factors of eventuality, work sequence, and method, it's difficult to take precautionary steps and redesign safety protocol.

The Domino Effect of Inadequate Risk Assessment

The consequences of insufficient risk assessment in accelerated construction methods can lead to a domino effect, where initial oversights cascade into a series of failures and revisions. This cycle not only jeopardizes project integrity but also endangers worker safety and project timelines.

Advancing Risk Assessment in Construction

To address the challenges posed by accelerated construction methods, the industry must prioritize the development of sophisticated risk assessment tools and methodologies. These should be capable of anticipating and adapting to every possible evolving condition of construction projects, ensuring that risk management keeps pace with technological advancements.

Conclusion

As construction methods continue to evolve, the approach to risk assessment must undergo a similar transformation. The current discrepancy between the rapid pace of construction and the slow evolution of risk assessment practices poses a significant challenge to the industry. By investing in advanced risk analysis tools and fostering a culture of proactive risk management, construction projects can achieve not only efficiency and productivity but also safety and resilience.