Structural engineer Michael Jackson Consulting Engineers called in Mabeys to lift the proscenium arch beam at the 150 year old theatre after cracks were found in the surrounding masonry.
The theatre had just started its run of Lillian Hellman’s play “The Children’s Hour” starring Kiera Knightly and “Mad Men” actress Elizabeth Moss when cracks in the auditorium wall signalled the need for immediate repairs.
The plan was to erect a tower after the last performance of the week and raise the beam, repair the masonry and then clear the site in time for the next performance on the Monday.
The base of the jacking tower was half on the stage and half in the auditorium which required detailed spanning grillages and back-propping to distribute the load and provide stability.
Effective teamwork was required to overcome several unforeseen problems. First of all the loadings were not as had been expected and a redesign of the temporary works was required. Then once work started, the damage to the masonry was found to be more extensive than predicted.
To ensure the disruption was kept to a minimum, Mabey installed a Mass 25 prop within the supporting wall on which the padstone bears, thus reducing the amount of masonry work.
Despite these major obstacles, the work was only marginally delayed and although the Monday performance had to be cancelled, everything was finished and cleared away in time for Keira and Elizabeth to take to the stage again on Tuesday night.
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