CIVIL WORKS CONSTRUCTION TECHNOLOGY 2017/18 COLLAPSE OF THE SCAFFOLDING DURING CONCRETING OF A BRIDGE DECK FORMWORK ERASMUS STUDENTS GROUP 2 Bruno Paladino Davide Spadafora Cécile Ottino Geoffrey Colinet Prof. Fernando Branco

SUMMARY 1. Introduction 2. Causes of scaffolding collapse 3. How to control and avoid accidents 4. Example of Formwork and Scaffolding Losses: Case study 5. Conclusion

INTRODUCTION SCAFFOLDING is a temporary structure used to support and to aid in the construction, maintenance and repair of buildings, bridges and all other structures made by man.

INTRODUCTION The purpose of this report is to analyze some possible causes of the scaffolding collapse, and suggest the controls that should be implemented to prevent accidents.

INTRODUCTION Example : 14 October 2015 in South Africa Collapse of a scaffolding of a bridge that was crossing a highway 2 people died 23 people were injured *The scaffolding of this bridge was built by FORM-SCAFF http://www.formscaff.com/projects/bridges

CAUSES OF SCAFFOLDING COLLAPSE GENERAL CAUSE OF THE COLLAPSE BRIDGES SCAFFOLDING Using scaffolding without design Poor design and error in load consideration Bad quality control in execution Bad quality control of the scaffolding Problems related to materials Foundation.

CAUSES OF SCAFFOLDING COLLAPSE USING SCAFFOLDING WITHOUT DESIGN Using scaffolding without design, usually happens in poor countries where people use scaffolding without design for economic reason.

CAUSES OF SCAFFOLDING COLLAPSE POOR DESIGN AND ERROR IN LOAD CONSIDERATION In general for poor design or error in load consideration the fault is of the designer that forget some considerations that are important in the work or don’t consider the really amount of the load that can be stored on the bridge deck during the construction.

CAUSES OF SCAFFOLDING COLLAPSE POOR DESIGN AND ERROR IN LOAD CONSIDERATION When the designer forget to take account all effective loads there are two problems on the general load not considered that can be: Dead load: is the self-weight of the scaffolding (that is, all structural components and equipment that form the scaffold like components for linkage and the bars, plank etc). Live loads: are all the temporary loads imposed on a scaffold.

CAUSES OF SCAFFOLDING COLLAPSE POOR DESIGN AND ERROR IN LOAD CONSIDERATION Designer should consider approximate number and weight things without mistake such as: Worker (the number of people involved) Equipments (plant and equipment that will be used on or near the scaffold) Materials (Estimation of General materials that using during constriction) Also the height of the scaffold local weather conditions

CAUSES OF SCAFFOLDING COLLAPSE BAD QUALITY CONTROL IN EXECUTION The coordinator or engineer should: Check if all the hinges and joints between scaffolding members its fixing well and respect the design and the directive of the seller or not. Check if the scaffolding props, the shoring, system are in vertical axis or inclined with different slope. Check the real distance between scaffolding members are the same with design.

CAUSES OF SCAFFOLDING COLLAPSE QUALITY CONTROL OF THE SCAFFOLDING The person supervising should:: Select and direct employees who erect, dismantle, move or alter scaffolds; Determine if it is safe for employees to work on or from a scaffold during storms or high winds and to ensure that a personal fall arrest system or wind screens protect these employees; Train employees involved in erecting, disassembling, moving, operating, repairing, maintaining, or inspecting scaffolds to recognize associated work hazards; Inspect scaffolds and scaffold components for visible defects before each work shift and after any occurrence which could effect the structural integrity of the scaffold.

CAUSES OF SCAFFOLDING COLLAPSE PROBLEMS REALTED TO MATERIALS The materials used in the construction of a scaffolding must be in good condition and in conformity to the European safety standards. The main problems regarding materials are: -Corrosion -Obsolete materials -Inadequate element

CAUSES OF SCAFFOLDING COLLAPSE SCAFFOLDING FAILURE DUE TO WEAK FOUNDATION Scaffold support is one of the most important problem in the scaffolding design because in most cases failures are caused by inadequate foundation. The main problems are: Soil condition; Weak soil Punching shear

how to control and avoid accidents In order to prevent accidents during the bridge works construction the following controls must be done: a) You have to comply with the the Directive 2001/45/CE of the European Parlament b) Have a control about the utilization of the same materials selected during the design, also for the construction.

how to control and avoid accidents c) Before construction we have to design the final framework; d) Have a control about the foundations of the scaffoldings. e) Have a control of Fatigue of the shoring or formwork

how to control and avoid accidents f) Have a control of the Concrete properties g) Control of Faulty workmanship.

CASE STUDY The term “falsework” is used for structures which combine the functions of Formwork and Scaffolding. This case from 2009 in Poland where a partial collapse of a bridge under construction.

CASE STUDY The investigation revealed two factors contributing to the collapse: The main cause was (once more) the lack of bracing to adequately counter lateral forces. Large quantities of reinforcing bars were temporarily stored on the bridge deck. These bars have imposed a load which was not considered in the original falsework design. The falsework design. Situation after the collapse

CONCLUSION In order to prevent accidents lot of controls should be implemented. Specifically: • Prevent workers about current regulations; • Improve the quality control of materials; • Use a suitable type of scaffold considering the site and the work that has to be done; • Make analyzes of the soil on which the foundations of the scaffolding will be built; • Provide more accurate periodic controls over the fatigue of the formwork; • Intensify controls of the competence of the workmanship; • Analyze the properties of concrete during hardening taking into account the vibrating loads and the flexural forces on the supporting beams.