DGS/SEE - GS/SE

1. DGS/SEE - GS/SE Report on the preliminary inspections to the Raised floors of sps buildings Marco Andreini, Raul Fernandez Ortega, Richard Francis Morton

2. Outline: • Structural defects detected at BA1 that caused the failure of a part of the false floor • Preliminary inspection at BA6 to detect the presence of similar defects and load patterns • Plan for the inspections and the structural safety assessment before the YETS 2015/2016 Report on the preliminary inspections to the raised floors of SPS buildings

3. The Structural failure occurred at the false floor at BA1 (03/09/15) The structural failure occurred to the false floor located at the ground floor of the Building BA1 and supporting an electrical converter has been caused by the self-weight of such an equipment. The structure consisted in a steel frame grid, composed of H-profiles arranged in a single way and restrained to an adjoining concrete slab by means of an L profile. Report on the preliminary inspections to the raised floors of SPS buildings

4. BA1: Structural joint between the steel false floor and the concrete slab The L-profile has been anchored to the slab by bolts (diameter ~= 18 mm), having a total length of roughly 100 mm, located on the vertical web and, in some points, with additional plates welded upon the horizontal flange. Report on the preliminary inspections to the raised floors of SPS buildings

5. BA1: Description of the joint parts collapsed The failure has been generated by the loss of bearing capacity of the L-profile connection 1 The failure occurred in a low tensile strength of the concrete surrounding one of the bolts Report on the preliminary inspections to the raised floors of SPS buildings

6. BA1: Description of the joint parts collapsed The failure has been generated by the loss of bearing capacity of the L-profile connection 2 Rupture of the fillet weld between the additional steel plate and the horizontal flange of the L profile Report on the preliminary inspections to the raised floors of SPS buildings

7. BA1 Comparison with existing drawings Existing drawings 1973 There is a perfect matching with the details from the drawings of the original structural project. Bad design or excessive load? Report on the preliminary inspections to the raised floors of SPS buildings

8. Reinforcing intervention was carried out (by whom?) in the past (before Sep, 3rd) ? Report on the preliminary inspections to the raised floors of SPS buildings

9. Issue rised Are there any other similar situations in the SPS buildings (BAs)? Report on the preliminary inspections to the raised floors of SPS buildings

10. BA6 – BA1 Comparison with existing drawings Same structural detail BA6 BA1 ! Report on the preliminary inspections to the raised floors of SPS buildings

11. BA6 Inspection: Comparison with the load pattern of BA1 BA6 BA1 What we understood: We have the same load severity in BA1 and BA6! The limit 500 kg/m2 indicated is WRONG! BA6 Report on the preliminary inspections to the raised floors of SPS buildings

12. BA6 Inspection: Comparison with existing drawings Perfect matching between the drawings and the real joint connection Report on the preliminary inspections to the raised floors of SPS buildings

13. BA6 Inspection: Comparison with the structural details of BA1 BA1 BA6 SAME detail + SAME load = SAME failure ?! Report on the preliminary inspections to the raised floors of SPS buildings

14. BA6: Moving materials and equipment strategy Moving by Pallet truck (Transpalette) allowed due to the presence of additional bridging joists BA6 Moving by Crane (Pallet truck “Transpalette” forbidden) Report on the preliminary inspections to the raised floors of SPS buildings

15. Actions Plan for the inspections and the structural safety assessment before the YETS 2015/2016 Report on the preliminary inspections to the raised floors of SPS buildings

16. Actions: Results to be obtained before the YETS 2015/2016 • Investigation of the existing status • Original drawings of the steel frames; • Map of the load patterns applied on the raised floors. • Description of the status of the structural elements. • Results of the inspections; • Structural safety assessment of the steel frames • Map of the false floors indicating: accessible, accessible with (temporary) measures/interventions, not accessible areas without further investigation. • Plan of interventions for dangerous situations. Report on the preliminary inspections to the raised floors of SPS buildings

17. Actions: role of the various working units • GS-SE (Synaxis): Etudes de la structure métalliques des faux plancher et plans d’exécution. • HSE: Contrôle et validation des notes de calculs. • GS-SE (Synaxis): Plans d’atelier. • EN-MEF: Réalisation- exécution des travaux. Plan of inspections (shouldbe…) • BA3-(26-11-2015) - Done • BA5-(30-11-2015) - Done • BA7-(30-11-2015) - Done • BA1-(4-12-2015) - Done • BA2-(4-12-2015) • BA6-(8-12-2015) • BA4-(8-12-2015) Report on the preliminary inspections to the raised floors of SPS buildings

18. Preliminary results of the inspections: BA3 Report on the preliminary inspections to the raised floors of SPS buildings

19. Preliminary results of the inspections: BA5 Pillar Report on the preliminary inspections to the raised floors of SPS buildings

20. Preliminary results of the inspections: BA7 Additional elements (beams and pillars) are present herein. Pillars Beam Pillar Report on the preliminary inspections to the raised floors of SPS buildings

21. Conclusions • The structural detail failed at BA1 seems to be recurrent even in almost all the BAs • The load severity of BA1 is similar to all the BAs • Some shoring intervention are required to allow the maintenance of the electrical component underneath some areas of the raised floor at BAs • A plan for the access underneath the raised floors of the BAs will be drawn before the YETS • Materials and equipment movements at BA6 are allowed using pallet trucks and crane in selected areas Report on the preliminary inspections to the raised floors of SPS buildings