Cvetkovska Meri Lazarov Ljupco Todorov Koce

1. COST Action TU 0904 “St. CIRIL and METHODIUS” UNIVERSITY FACULTY OF CIVIL ENGINEERING SKOPJE - MACEDONIA Cvetkovska Meri Lazarov Ljupco Todorov Koce EXAMINATION, ASSESSMENT AND REPAIR OF RC STRUCTURE OF BUILDING DAMAGED IN FIRE

2. COST Action TU 0904 Characteristic damages of RC elements recorded in situ Change of concrete color. Red color indicate temperaures round 6000C Flexy color indicate temperaures round 9000C

3. COST Action TU 0904 Characteristic damages of RC elements recorded in situ Cracks along main reinforcement Cracks in direction of stirrups Crushing of concrete and falling off of concrete parts along the edges of linear elements up to the reinforcement

4. COST Action TU 0904 Characteristic damages of RC elements recorded in situ Change of color and structure of concrete(fissures and cracks inside the concrete mass)

5. R4 S4 S1 A E7 B8 R1 R3 MS P1 D7 S3 S2 R2 G7 V7 T2 SII COST Action TU 0904 Experimental determination of the residual concrete strength Position of the test specimens, taken from RC walls and RC slabs on 7th and 8th floor

6. Before testing all the specimenswere divided in two slices. The deteriorated (burned) slices had small height (3-6cm) and rough surface They were specially prepared by adding plaster layers, so the measured values for the compressive concrete strength were reduced with coefficients depending on the shape and height (h) of the deteriorated concrete specimens COST Action TU 0904 Experimental determination of the residual concrete strength

7. Concrete strength testing results COST Action TU 0904

8. Schematic presentation of fired frame R2 (elements discretization and details of reinforcing) N=3500KN N=3500KN N=3500KN N=3500KN 24 6 12 18 30 5 17 23 29 11 122+616 616 216 P.900 316 316 516 1418 1418 10 16 22 4 28 P.800 3 9 15 21 27 P.700 8/15/15cm 2 8 14 20 26 P.600 1 7 13 19 25 1.7 1.7 1.2 1.7 1.7 1.2 1.2 1.8 1.2 1.2 1.8 1.2 1.2 1.2 4.22 5.8 4.2 5.8 59 87 31 73 45 46 74 88 32 60 47 61 33 89 75 90 48 76 34 62 35 49 77 91 63 64 36 50 78 92 93 79 65 51 37 52 66 38 80 94 81 53 39 95 67 40 68 82 54 96 69 97 55 83 41 70 84 56 42 98 99 85 43 71 57 100 44 86 72 58 COST Action TU 0904 Thermal and structural response of four-bay, five-story RC frame

9. b) a) COST Action TU 0904 Thermal and structural response of column S4 a) temperature distribution b) residual concrete strength in the cross section of the most damaged column

10. 10 16 3 1 COST Action TU 0904 Thermal and structural response of column S4 b) a) a) stress distribution b) stress distribution at max. temperatures after the cooling period

11. 0.30 m 0.30 m COST Action TU 0904 Thermal and structural response of the beam RC slab a) b) a) temperature distribution b) residual concrete strength in the cross section of the most damaged beam

12. 10 16 3 1 -100 -75 -50 (T) -25 y -2 -6 -10 f of 0 % 25 arm.3 in s 50 arm.10 75 100 e *1000 Time redistribution of stresses in reinforcement in the cross section of the most damaged column Thermal and structural response of four-bay, five-story RC frame

13. COST Action TU 0904 Interaction diagrams for column S4 M-N diagram for column S4 (before action of fire and at the moment of max. temperature)

14. COST Action TU 0904 Interaction diagrams for column S4 M-N diagram for column S4 (before action of fire, at the moment of max. temperature, after cooling phase and after replacement of 5cm thick layer of burned concrete)

15. M-N diagram for column S4 (before action of fire, at the moment of max. temperature, after cooling phase and after suggested repair with “jacketing”) COST Action TU 0904 Interaction diagrams for column S4

16. 2 5...50 RC wall 30 cm additional reinf.:18 RA 400/500 2 5...50 d6cm addit. reinf.:18 RA 400/500 new concrete layer МВ 35 33 cm d=5-6cm stirrup: 10/7,5/15cm GA 240/360 additional reinf.:218 RA 400/500 lean concrete layer thermal isolation 5 cm 66 cm “OMNIA” slab 15 cm •  5...50 • welded to the existing stirrup 60 cm new concrete layer МВ 35 45 cm d6cm d3cm add. stirrup 10/10/20cm GA 240/360 additional reinf.:220 RA 400/500 66 cm COST Action TU 904 Suggested repair of fire damaged structural elements Repair details of column S4 and beams from frame R2

17. additional stirrups n=362 (welded to the existing stirrups) existing reinforcement 60 RC wall, d=25cm concrete cover to be eliminated up to the existing stirrups S1 S2 add. reinforcement 20 (at the inside) 5 216 7 116 8 116 70 570 60 190 2 120 L=7.25m , n=12 5 216 L=3.20m , n=22 8 116 L=2.65m , n=12 7 116 L=5.7m , n=12 15 15 695 RC wall, d=25cm RC wall P1, d=30cm concrete cover to be eliminated up to the existing stirrups RC wall existing reinforcement 60 S3 S2 Detail “B” Detail “С” opening through the RC wall (for the add. reinforcement) 30 375 60 520 60 260 315 570 Suggested repair of fire damaged structural elements Detail of additional reinforcing with 20 (RA 400/500-2) along the beam of the frame R1 Detail of additional reinforcing with 16 (RA 400/500-2) along the beam of the frame R2

18. COST Action TU 0904 Thank you for the atTention