PLANT MACHINERY & SITE SAFETY
often show visible deformation before structural failure, site teams may perceive them as ‘forgiving’ of deviations.
This is a dangerous misconception. Most excavation incidents don’t happen because the equipment suddenly fails, but because the excavation has already moved beyond the conditions it was designed for, and that change hasn’t been recognised or controlled.
REVERSING THE TREND
To reverse this trend, the industry must move away from treating shoring installation as a routine activity and return to viewing it as a critical engineering stage. Failures are frequently linked to specific deviations: incorrect spacing, incomplete installation, or allowing excavation to progress too far ahead of the support.
We do not necessarily need constant redesigns, but we do need a more realistic definition of the design envelope. Suppliers often design to a narrow brief to remain competitive. It is the responsibility of the contractor and the Temporary Works Coordinator (TWC) to define a realistic envelope at the outset, including credible worst- case conditions – such as groundwater at ground level or maximum possible surcharges – rather than a single best-case snapshot.
If I could mandate only one change across UK sites, it would be a rigorous requirement to verify that site conditions match design assumptions before the first bucket hits the ground. Excavations should not proceed on the basis of a drawing alone. There must be a clear ‘hold point’ where a competent person confirms that the geometry, soil, and loading are consistent with the engineer’s intent.
THE COST OF DEVIATION
We must leverage technology to bridge the skills gap. Digital monitoring, such as proprietary load-monitoring
sensors on hydraulic struts, provides real-time data that human observation might miss. Beyond visual checks, engineers must look for indicators that the excavation is no longer behaving as assumed. This includes subtle ground movement, softening of the formation, or changes in load distribution such as poor seating of components.
Consider an urban basement excavation where the design assumed a specific surcharge from nearby plant machinery. On-site, due to space constraints, a heavier crane was positioned closer to the excavation edge than planned. Because the ‘design envelope’ hadn’t accounted for this deviation, the shoring system began to show subtle signs of distress, including tension cracking and unexpected water ingress.
In this instance, early recognition of these indicators allowed for a dynamic review and the installation of additional lateral support. Had the site team relied on the perceived ‘robustness’ of the equipment without questioning the change in parameters, the 50% breach statistic would likely have claimed another project.
A SAFER FUTURE
Reversing the rise in excavation breaches requires more than incremental equipment upgrades; it demands a fundamental shift in site culture and a commitment to deeper collaboration between contractors and specialist suppliers.
While proprietary systems are a formidable line of defence, they are not a substitute for rigorous engineering oversight. By narrowing the gap between the design office and the trench, and ensuring the TWC is empowered to halt works when reality drifts from design, we can ensure that a ‘zero-failure’ site culture becomes an industry standard, rather than a moving target.
www.vpgroundforce.com/gb/
19
WWW.TOMORROWSHS.COM
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40
