Building sites are often messy places, with construction materials, cranes and contractors all vying for the same precious space. But it doesn't have to be like this, particularly if you consolidate all materials and components off-site and truck them in as required. Walter Poetsch explains how it's done.
Why does every construction project fall behind schedule? Are programmes unrealistically tight? Are the management team or specialist trade contractors not up to delivering the strategy?
Construction projects typically involve a complex interaction between work areas, a large, multi-disciplinary workforce, a vast quantity of materials, tools and equipment, and a wide range of assorted project information. If any of these four key elements are not precisely defined and delivered for every construction task, then thereâ€™s a high risk of health and safety, quality and productivity problems.
BSRIA studied three new developments in central London over a period of 120 days to find out how effectively and efficiently the materials logistics process operated, and whether the use of a consolidation centre for construction materials had improved the performance of each project, and in what ways.
On all three projects, specialist trade contractors kept construction materials in a consolidation centre - effectively a storage warehouse located off-site. The specialist contractors and building suppliers delivered materials to the interim storage facility 2-3 days in advance of when they were needed on site. The subcontractors would then call-off items for delivery to working areas as and when they were required. The correct items were delivered to a site holding zone or directly to the trade contractors working area.
Working this way, a consolidation centre only needs to stock materials for a 10-day lead-time. Once the site-manager calls for the material, it's packed onto a lorry. Other trades' materials can be included to achieve an optimum loading efficiency, fewer trips to site, and hence reduced CO2 emissions.
Does it work?
The consolidation centre method is simple in theory, but can be tough in practice. In reality, it requires thorough forward-planning, involving all management levels and functions, and support from the workforce from the start.
On all three study projects, a specialist logistics contractor distributed materials to the working areas. On the best performing site (figure 1) this reduced materials delays to one third of the level normally found on construction sites (from 48 minutes to 18 minutes per installer).
Delays were created by the illogical stacking methods used by sub-suppliers and trade contractors, as well as with the multi-handling of materials, unclear or unmarked holding areas, improper or nonexistent racks, and damaged ramps and pallets.
Productivity gains were also compromised by an absence of workbenches, and the inability of the skilled labour to organise themselves effectively.
Figure 1 shows the measured collecting and waiting time for materials on site for all three projects studied by BSRIA. Compared with study projects 1 and 2, the percentage of lost time on project study 3 due to material delays was lower by 1.4 percent. This could indicate a stronger commitment of the workforce, as well as better organised deliveries and better unloading and delivery procedures.
Project 3 also had a better traffic movement system around the gates. A one-way road system helped to reduce disruptive driving manoeuvres and allowed the traffic marshalls to close and/or block-off the road for all three gates quickly when needed. Although a demolition company worked opposite, using the same access, very little disruption occurred.
BSRIA interviewed all parties on the projects to get feedback.
The interviewees felt that the weakest part of the material delivery process was the stage from the delivery lorry to arrival at the specified location required by installation teams. Other issues, such as inappropriate or insufficient material handling equipment, poor management of distribution routes and imprecise coordination of storage locations and work locations were identified as key weaknesses. Good project programme management was identified as the key to success.
- A consolidation centre can deliver well-organised materials to projects, consistently, and on time. However, things can conspire to prevent it generating the anticipated savings, such as:
- too many material deliveries arriving on site through processes that bypass the consolidation centre
- a lack of co-ordination over the distribution and storage of materials
- a failure of construction progress where material deliveries are not controlled, causing too much material to be delivered
- a lack of precise planning and control over the site logistics process.
For more information contact BSRIA:
Tel: +44 (0) 1344 465600
or email firstname.lastname@example.org