BRE BR451 PDF

Introduction

High alumina cement (HAC) concrete was used extensively in the UK from the 1950s to the early 1970s in the manufacture of pre-cast, pre-stressed concrete beams. Extensive research into the structural performance of HAC concrete construction led to the publication of detailed guidance and recommendations on design-check procedures by the Building Regulations Division of the Department of the Environment (DoE) in 1975. This guidance (commonly known as the BRAC* rules)(1) is the best advice available and is still used today to assess the structural performance of the many tens of thousands of buildings in the UK containing such pre-cast HAC concrete beams. However, these documents have been out of print for a number of years.

This report incorporates the original documents with redundant information removed and additional and revised information is included where relevant. Wherever possible, the original wording has been retained with explanatory footnotes added where subsequent developments in codes, standards or knowledge are relevant. A limited amount of new text (in italics) has also been added. The original documents themselves (the BRAC guidance and their two addenda)(1), are now also available in electronic form on a BRE CD-ROM (see BR429). These brief overview pages are intended to set the BRAC documents in context with current thinking and the guidance on HAC concrete published since 1975. They also give some general guidance on their application.

The UK stock of HAC concrete buildings is now all over 25 years old and there is demand within the engineering community for methods and guidance for assessing their performance in service. There are many thousands of HAC concrete buildings in the UK and there are significant benefits in maintaining this national asset. A recent BSRIA report(2) has shown that refurbishing and renovating such concrete buildings has real benefits to project costs and maintenance of the UK building stock.

* Building Regulations Advisory Committee Sub-committee P