Reinforced Concrete Inspection Pit at Watts Gallery

The Challenge

Watts Gallery needed a new reinforced concrete inspection pit inside an active, densely packed plant room, to give permanent access to crucial buried services. The plant room sits right next to the live art gallery.

We broke out a 3 × 2 m section of the existing 600 mm thick reinforced slab using hand equipment, then excavated by hand to over 2 m to avoid the buried services. The new pit was formed with 200 mm walls containing two layers of A393 mesh, U-bar end reinforcement and 16 mm bars laced throughout.

How We Did It

Dust from cutting was controlled with water spray and pump systems. Noise was managed with suppressed electric breakers and temporary noise barriers to protect the gallery next door, and all material was removed by hand.

An existing cast-iron drain pipe found at the edge of the excavation meant the pit geometry had to be adapted, which made the shuttering more complex. The works were still completed to a good standard, on programme and within budget, with the client happy with both the result and how the live environment was managed.