Prof studied concrete slab collapse prevention

Prof John Smallwood reports on concrete slab collapse prevention. He quantifies the relative importance of health and safety registration.

The draft feedback report on Preventing the collapse of reinforced concrete structures, support work and formwork during construction (2016), unpacks the results of a survey of construcdtion employers.

It follows continuing collapses of some structure, support work and formwork.

The traditional three project parameters of quality, cost, and time, are perceived to be more important than health and safety to construction employers, found Prof Smallwood.

His conclusions include that competencies, design, registration of built environment professionals, hazard identification and risk assessments (HIRAs), supervision, quality management, H&S management, risk management, planning and H&S planning in various forms, integration of design and construction, and the construction work permit, are all important as clusters of factors, or individually, relative to preventing the collapse of RC structures during construction.

Recommendations include that conformance to requirements is the key, that such recommendations be scientifically evolved and communicated, a pre-requisite being that the required competencies exist, which can only be assured through a formal registration process, including that of contractors.

Ideally, multi-stakeholder project H&S, quality, and risk plans should be evolved, and design and construction must be integrated. Then, general construction management and H&S planning must be a hallmark of all projects, and then optimum management and supervision to ensure execution of such planning.

Quality management is critical in terms of assuring the structural integrity of permanent and temporary structures.

Among the more important factors to employers are;
• Construction Management’s construction management competencies’ (1st)
• Construction Management’s structural competencies’ (4th)
• Construction Management’s temporary works design competencies’ (7th).

Construction Management programmes include three main streams; economics, management, science and technology. However, their ability to do so must be assured, hence ‘Registration of Construction Managers’ ranks eighth.

Design of the permanent structure ranked second, and ‘Registration of Engineering designers’ ranked third as the former is a pre-requisite for the prevention of collapses, and the latter assures that the designers are competent.

Construction health and safety roles
‘Construction hazard identification and risk assessments (HIRAs)’ and ‘Design HIRAs’ ranked fifth and sixth, relevant to planning in general and ‘prevention through design’.

Safe work procedures (SWPs)’ ranked eleventh. ‘Dedicated contractor supervision of the structure during construction’ ranked tenth.

‘Temporary Works Designers’ temporary works design competencies’ and ‘Temporary Works Designers’ structural competencies’ ranked ninth and twelfth.

Thirteenth ranked ‘Project quality management (overall)’, indicating a link between H&S and quality.

Among the lower half of factors are ‘H&S Plan (Contractors) e.g. support work contractor’ ranked fourteenth, and ‘Contractor project risk management plan’ ranked twentieth.

‘H&S Plan (Principal Contractor)’ is ranked 25th. Related ‘H&S method statements’ is ranked 21st.

In terms of management and management systems, ‘Contractor H&S management system’ is ranked fifteenth, ‘Project risk management (overall)’ eighteenth, ‘Contractor risk management system’ twenty-third, and ‘Project H&S management (overall)’ twenty-fourth. Supervision features in the form of ‘Close contractor supervision of the structure during construction’ ranked sixteenth, and ‘Close engineering designer supervision of the structure during construction’ ranked twenty-second.

It is notable that ‘Temporary works design (scientific)’ is ranked seventeenth, whereas ‘Design of the permanent structure’ was ranked second. Furthermore, ‘Integration of design and construction’ which links the aforementioned is ranked nineteenth. A range of competency related factors are ranked between twenty-sixth and 44th.

Perceptions of construction health and safety functions
It is notable that ‘H&S Agents’ (Client appointed) structural competencies’ (26th) and ‘H&S Agents’ (Client appointed)
H&S competencies’ (27th) are ranked higher than ‘Temporary Works Designers’ construction management competencies’
(28th), followed by ‘H&S Agents’ (Client appointed) temporary works design competencies’ (29th)

‘Construction Management’s H&S competencies’ is ranked as a lower factor in preventing concrete slab collapses (30th), with ‘H&S Officers’ H&S competencies’ (32nd), ‘H&S Agents’ (Client appointed) H&S competencies’ (33rd), and ‘Temporary Works Designers’ H&S competencies’ (38th).

Construction health and safety registration ranks lower
Among the professional registration factors, are ‘Registration of H&S Managers’ (ranked 34th), followed by ‘Registration of H&S Officers’ (42nd).

The relationship between H&S and risk management and quality management features in the form of ‘Project risk schedule (overall)’ (31st), ‘Contractor quality management system’ (35th), and ‘Contractor project quality plan’ (40th).

The importance of planning relative to H&S is reflected in ‘Construction method statements (generic)’ (36th), and ‘Contractor planning’ (37th).

It is notable that although ‘H&S Plan (Principal Contractor)’ was ranked twenty-fifth, it was followed distantly by two factors with which it is directly related, namely ‘H&S Specification (issued to the Principal Contractor)’ (39th), and ‘Designer report submitted to the client ito a response to the H&S Specification’ (41st).

Construction Work Permit (DoL) (ranked 45th), in terms of the Construction Regulations Amendment 2014, is intended to act as a filter in ensuring that clients’ baseline risk assessments (BRAs) and Health and Safety Specifications (issued to designers) (ranked 46th).

Registration of Health and Safety Agents (Client-appointed) (ranked 47th) is considered less important than Registration of Engineering designers (ranked 3rd), Registration of Construction Managers (8th), Registration of H&S Managers (ranked 34th), Registration of H&S Officers (ranked 42nd)

Among the lowest perceived prevention factors are ‘Registration of Project managers’ (52nd), Registration of Architectural designers (59th), and Registration of Quantity surveyors (60th).

Competency related factors include:
• H&S Officers’ temporary works design competencies (ranked 49th)
• Temporary Works Designers’ project management competencies (53rd)
• H&S Agents’ (Client appointed) project management competencies (54th)
• H&S Officers’ construction management competencies (55th)
• H&S Officers’ structural competencies (56th).

The importance of non-H&S competencies to H&S Agents, and H&S Officers, rank very low. Likewise ‘Municipal approval of plans (prior to construction) (51st) and ‘3rd party review of the design of the permanent structure’ (58th) are ranked within this cluster.

However non-approval of plans has been linked to buildings and structures that have collapsed.

The perception survey draft report also quantifies industry views on technical factors relative to preventing the collapse of reinforced concrete structures during construction, and factors relative to optimum support work and formwork and the integrity of structures under construction.

Factor analysis is a method for investigating whether a number of variables of interest, are linearly related to a smaller number of unobservable factors.

Construction safety recommendations
Prof Smallwood concludes that “the construction industry collectively is perpetuating the paradigm of quality, cost and time, to the detriment of construction health and safety.”

Given the importance of factors in terms of preventing the collapse of RC structures during construction, and identification of six groups of factors, the required mixture of factors should be in place, and to an optimum extent. The same applies to support work and formwork and the integrity of structures under construction.

Conformance to requirements is the key, including compliance to municipal approval of building plans, and construction work permits.

However, a pre-requisite for conformance to requirements is that many of the requirements should be scientifically evolved and communicated. In parallel, the required competencies must exist, or the aforementioned cannot be achieved.

“Competencies can only be assured through a formal registration process such as required by the six South African built environment councils.

“Registration of contractors should interrogate H&S, quality, and risk management systems and practices. Clearly, contractors should also be pre-qualified in terms of H&S, quality, and risk management systems and practices.”

Ideally, multi-stakeholder project H&S, quality, and risk plans should be evolved. Design and construction must be integrated and the ‘grey areas’ relative to achieving same must be addressed.

General construction management and H&S planning must be a hallmark of all projects. Management and supervision are critical.

• Source; Prof John Smallwood, Department of Construction Management, Nelson Mandela Metro University, Port Elizabeth

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2 thoughts on “Prof studied concrete slab collapse prevention

  1. Hi Prof,
    Thank you for this great article. I must say however that some of your findings are not a suprise. The ranking for HS persons reflects what i am seeing on site. The implementation of the Construction Regulations is weak, the RA/HS Specification are 99% inadequate and the plan, is not really a plan, but a non=descript document, clouded by “cut and Paste” of the regulations. I have had to work extensivily with many contractors to somewhat get some sort of relevance to the work they are actually performing.

    You research is well received, and hopefully i will be able to use in the course of my work as a ” change agent”


  2. PS
    My contractors are really peeved with me as i require a Pr.Eng to sign off any temporay works….i get death stares in meetings


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