435 Balcony strengths of blocks of flats - further experiences
In recent years, says a reporter, his firm has been undertaking structural assessments of cantilevered reinforced concrete walkways on a large number of two storey blocks of local authority-owned residential flats. In the majority of cases the walkways have been found to be under strength. The flats were all constructed between the mid 1950’s and mid 1970’s and have cavity masonry walls supporting a reinforced concrete first floor slab with a pitched tiled timber roof above.
442 Apollo Theatre London ceiling collapse
In January 2014 Westminster City Council circulated some interim guidance regarding the management of suspended ceilings. The investigation of the partial collapse of the suspended ceiling at the Apollo Theatre in Shaftesbury Avenue London is still in progress and the Council now have a better understanding of the failure mode of the ceiling. A key element of the interim advice is for theatres to understand the form of construction of their individual ceilings and how the constituent parts are joined together and ultimately supported from the main structure. Some of the relevant information about the Apollo Theatre ceiling is given in this report.
Two reports in this issue are about older structures; firstly the finding of a large number of reinforced concrete cantilever balconies with the critical top reinforcement in the bottom, and secondly advice from Westminster City Council on suspended plaster ceilings in theatres. Concerns on site matters are included in reports on a mobile tower blown off a building, collapses of twin wall shuttering systems and another case of anchors failing under load.
The programme depends on receiving reports and individuals and firms are encouraged to participate by sending concerns in confidence to Structural Safety.
Structural-Safety combines CROSS and SCOSS to work with the professions, industry and government on safety matters concerned with the design, construction and use of building and civil engineering structures. It:
CROSS (Confidential Reporting on Structural Safety) aims to improve structural safety and reduce failures by using confidential reports to highlight lessons that have been learnt, to generate feedback and to influence change. SCOSS (The Standing Committee on Structural Safety) is the independent body established in 1976 to maintain a continuing review of building and civil engineering matters affecting the safety of structures. SCOSS aims to identify in advance those trends and developments which might contribute to an increasing risk to structural safety.