Forensic Engineering 2022: Collaborative Reporting for Safer Structures

In the decade from 1978 to 1987, the US experienced an unprecedented rash of catastrophic structural collapses, many resulting in tragic loss of life. This paper reviews nine of these, identifying similarities and differences in their causes, and exploring possible reasons why such a concentration of failures occurred then. Furthermore, these failures caused professional and public outcry, motivating continuous efforts and progress to improve public safety. Our diligence in learning from failures and keeping public safety at the forefront of our work must be never ending. The CROSS system plays a vital role in this pursuit. By sustained learning from failures of all consequence, as well as incidents, and safety concerns, we can avert catastrophes.

CROSS (Collaborative Reporting for Safer Structures) captures safety concerns and events from submitted reports and shares lessons learned from them. The objective is to identify pre-cursors and help prevent future failures and loss of life. CROSS has a volunteer panel of expert engineers covering a wide spectrum of the design and construction sectors who comment on reports in a no-blame environment. These are published and examples will be given. Moreover, in 2017, a fire in Grenfell Tower in London resulted in 72 deaths. The UK Government commissioned an independent review of building regulations and fire safety: the Hackitt review. Included in the recommendations was a proposal that CROSS should be strengthened for structural safety and expanded to include fire safety. Results from this enhanced system will be available to all at no cost and the results will be used to inform the new UK Building Safety Regulator whose role is being formulated. Furthermore, as CROSS became established, there was interest from like-minded groups in other countries and currently there are schemes in the US (CROSS-US) and Australasia (CROSS-AUS) which will be covered in other papers of this session. Thus, the ultimate aim is to have a global network of CROSS communities who exchange reports and publish material that will help to keep users of buildings safer. This will be a resource for owners, design practitioners, builders, regulators, academics, and of course the public.

The systems of codes and standards that regulate structural engineering practice in the US are complex. The Federal government cannot enforce a national building code, that authority rests with the States, and in many States, that authority is delegated to local governments. There are a multitude of private sector organizations that develop standards. There are thousands of standards that are incorporated by reference (considering direct and indirect citations) into the most commonly used model building code. There are separate model codes for highway bridges and for rail bridges, which are similarly complex. CROSS-U (Collaborative Reporting for Safer Structures), along with the CROSS efforts in other nations and regions, will find issues that justify changes in the practice of engineering and construction. Some of the necessary changes will inevitably imply changes to model codes, design standards, quality control and quality assurance processes, and certifications. Conceivably, additional layers of experts will need to be added with expertise in the many aspects of practice that could be affected, and just as importantly, who can serve as champions for the needed changes in particular standards. Models of coordinated activism exist and are recommended for review and study, to better understand successful strategies and tactics for future improvements.

Following the Hackitt recommendations on the Grenfell fire in London and the publication of the Building Safety Bill, the UK Government provided funds to further develop CROSS. From user research, it was confirmed that CROSS was a trusted resource and that the publications were valued, but the brand was restricted to structural engineering. To be meaningful for fire safety, the synonym had to be changed, and the new descriptor for CROSS—Collaborative Reporting for Safer Structures was adopted. Also, a major part of the development was to be a completely new website with two main segments: a front end for public viewing, and a back end content management system for handling reports. The characteristics that would appeal to a wider demographic of those in the building industry, and a new demographic for the fire sector would be included. Ease of navigation was a primary objective along with a user-friendly approach to submitting reports. The number of reports was expected to rise significantly so processes were devised to handle these in an efficient, robust, and confidential manner.

As outlined in our companion CROSS session, Glenn Bell discusses the 1978 through 1987 “Decade of Disaster” where the US experienced an unprecedented rash of catastrophic structural collapses, many resulting in loss of life. CROSS-US, following in the footsteps of CROSS-UK and utilizing its website, format, and structure, provides a forum for the Architecture/Engineering/Construction (AEC) industry in the US to confidentially report design and construction problems, failures, and near-misses to provide lessons learned to improve the structural safety. CROSS-US joins with CROSS-AUS (Australasia) as one of the international arms of CROSS. Furthermore, now in its third year of operation, CROSS-US has been established as an entity of the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE). It has published reports covering a wide range of topics including various roof collapses, seismic retrofit concerns, tower crane collapses during dismantling, ethical responsibility during delegated design, and a “Legacy Report” on the Hartford Coliseum roof collapse.

The fundamental rationale to ensure structural safety and to prevent society from undue harm in Germany, i.e., the independent design review scheme and the independent execution supervision system, will be explained. Special emphasis is laid on the methods chosen for the review and the supervision, as well as on the qualification needed for the design review engineer, who acts as a trustee of the public administration. The development of the design review and the execution supervision regime, and of the underlying set of technical rules and regulations will be addressed by discussing actual and historic case studies. The interface-problems, when different parties are involved, are highlighted and the necessity, to establish good and reliable coordination mechanism is carved out. Because of the increasing fragmentation of the design process, in combination with the use of complex software tools and inevitable pressure of time, often the comprehensive design review process is the last line of defence to avoid incidents due to minor lapses or serious misjudgements.

Several events in recent years in Australia and New Zealand have raised serious concerns about safety in the construction industry resulting in calls for significant changes in how it operates. The paper will include reference to the Shergold Weir Building Confidence report commissioned by the Australian Government that raised concerns about the effectiveness of compliance and enforcement systems for the building and construction Industry across Australia. The CROSS-AUS website parallels the same format and structure as the parent UK website, to which it is linked, and operational systems are the same. One of the challenges has been to widen the reach of CROSS-AUS to engage with as many as possible and CROSS-AUS now includes amongst its supporters Australian Certification Authority for Reinforcing and Structural Steels, Engineers Australia, Engineering New Zealand, and the Structural Engineering Society of New Zealand. Now in its third year of operation, CROSS-AUS has published reports covering a wide range of topics from problems with roof soffit linings and light gauge steel fabrication to more fundamental questions of competency, the quality of structural design, and the maintenance of structures. This paper provides an outline on the development of CROSS-AUS and samples of the reports produced.

The paper will set the context for fire safety in the UK up to the time of the Grenfell Tower fire and provide a synopsis of changes currently being considered. It will map the significant developments in the regulatory systems that impact on design, construction, and management of buildings. It will emphasise the important role of a confidential reporting system to help gather information from responsible professionals, in a performance-based design regime. In comparison to other engineering disciplines, fire safety is relatively young. For most of the 20th Century the focus was on firefighting, deploying systems designed after World War II to provide emergency response, with very little emphasis on fire safety design. Large fires with multiple fatalities lead to some major changes, from the 1960s, the fire brigades became increasingly involved in approval and enforcement. Standards were broadly prescriptive, but the vast majority of designs were conservative in terms of complexity and materials. Thus, the Grenfell Tower public inquiry, a review by Dame Judith Hackitt and the discovery that hundreds of residential buildings over 18 m (59 ft) tall had unsafe external wall systems has exposed systemic failings. The UK, quite reasonably, appears to be wedded to performance based design but is increasingly recognising that design freedoms should only be exercised by competent ethical professionals. Part of being “professional” is to contribute to ongoing improvements to the profession. This is, in part, being enabled by the expansion of CROSS, a system that has achieved significant success for the structural safety profession. The paper will describe how fire safety professionals report to CROSS, what is being reported, and how the information is being used.

Numerous life-loss events over the past two decades have reinforced the need to critically examine how the architectural and engineering community approaches fire and life safety for innovative new and complex existing buildings alike. Recent incidents demonstrate that standardized approaches to performance-based analysis need to be implemented by designers, and that a system to vet those designs should more readily be accommodated by public agencies responsible for review. While advances in structural analysis and building modeling have facilitated the design of structures that expand the imagination, the approach to fire and life safety has not evolved at the same pace. This paper examines the relationship between failure analysis and the use of Performance-Based Design in the built environment. The role of post-incident analyses in discovering previously unknown behaviors and the translation of scientifically based analysis into a workable design framework is addressed. Additionally, the contribution of empirical data and the importance of establishing standards of practice that inform how professional engineers should approach their designs is explored in the context of a healthy Performance-Based Design ecosystem.