Lock 27 Lapworth Bottom Lock

Civils Rowington 0.16M 10 Weeks March 2009

Lock 27 Lapworth Bottom Lock

Lock 27 Lapworth Bottom Lock

Background

The existign lock chamber at Lock 27 Lapworth Bottom Lock was classed as condition grade D and in need of repair. The principal maintenance issue was a bulge in the offside wall between the mid point and the bottom lock gate.

A layer of silt had developed between the outside brickwork skin and the remaining structure. Furtehr investigation releaved that a void was present between the ouside brickwork and the remaining structure for almost the full length of the lock chamber. The outside brickwork, 225mm thick had separated fromt he rmeianing structure.

In addition to the presence of voids the wall had been subject to heavy mortar loss along most of its length.

The works involved the replacement of the outside brickwork, 225mm thick for the entire length of the offside wall to a depth of 2.4m from coping level.

Stainless steel ties were drilled and fixed to the remaining structure and built into the new brickwork. The nnulus between the new and old brickwork was filled with a non shrink cementitous grout.

In order to enter the chamber to undertake the necessary repairs the lock had to be made safe. Heavy duty temporary steel propping was introduced to support the existing offside wall. The lock was frunished with a full scaffold consisting of two working lifts.

Difficulties encountered when undertaking the works included the poorer than expected condition of the remaining structure which resulted in additional temporary works propping, hampering access and egress and more permanent works in the form of deeper brickwork replacement and additional grouting.

The works progressed well despite the above difficulties, although there was a requirement to work additional hours, weekends in order to meet the planned completion date / navigation closure end date.

Other difficulties included access, remote location requiring boat transport and maintaining a suitable temperature within the lock to permit bricklaying. Heaters were used to artificially maintain the temperature within the lock. The lock itself was tented to prevent freezing conditions and frost damage.

The works were completed on time and the condition of the finished works was regarded as very good.

Location: Rowington Cost: 0.16M Duration: 10 Weeks Completion: March 2009