SHORING SUPPLIER Groundforce used its rolling strut trench box for the first time in the UK on the A2/M2 widening project in Nashenden, Kent.
The box supported a 4. 14m wide trench being dug for a concrete drainage culvert. Ten of the 3. 4m wide, 4m deep trench boxes were used in the chalk for joint venture contractor CSM.
The shoring enabled the precast top sections of the culvert to be manoeuvred into position easily and safely.
A single moveable strut, which can be easily repositioned, allows maximum access for excavator buckets and other items of plant. At the A2/M2 site the rolling strut trench box allowed the trench to be supported while precast culvert sections were lowered in.
Construction started by placing the boxes in the trench, with struts positioned near the bottom. A reinforced concrete base was then cast to form the lower part of the culvert. The struts were raised to their highest position, giving 3. 1m of working space below and allowing the culverts' precast top sections to be placed on the bottom sections. Once the culvert was assembled, the boxes were removed and the trench backfilled.
Groundforce says its rolling strut trench boxes are capable of supporting trench widths from 1. 24m to 6. 24m and have a safe working load of 34kN/m 2with the strut in any position.