L.D. Dobrushin, A.G. Bryzgalin, S.D. Ventsev, and K.Yu. Korzin, S.D. Ventsev, and K.Yu. Korzin, J.G. Moon (Korea) EXPLOSIVE JOINING OF BUILDING BARS The National Academy of Sciences of Ukraine The E.O. Paton Electric Welding Institute The E.O. Paton Electric Welding Institute

1. The Description of the Technology The basic scheme : 1 – ends of armature to be connected; 2 – sleeve; 3 – charge. Essentially technology consists in the following: the ends of two rods of connected armature 1 (drawing) are place into steel cylindrical sleeve 2. The charge of the explosive 3 is placed on the external surface of the sleeve, blasting of which leads to clamping of sleeve’s wall in such way, that a metal of the sleeve pressed in space between armature transversal out dents.

2. Demonstration of the Technology The view of armature ends, sleeve and charge on it, made from detonation cord (left) and the joint, obtained by explosion clamping of sleeve (right)

3. Macro Section of the Reduced Sleeve with Building Bar after Explosion

4. The results of Strength Tests Sleeve dimensions were chosen from the condition to provide equal strength of joint and armature bar metal. About 30 joints of armature bars (Ø 25, 28 и 32 mm) were tested. In all cases the armature bar metal was destroyed.

5. The Results of Fatigue Tests Fatigue tests by longitudinal stretching were carried out on armature Ø of 32 mm according to the state standard at r = 0,4 on the basis of 2 million cycles. Special coefficient, characterizing the cycle durability of the joint, must be not less then 0,75. The value of received one was 0,87.

6. Stand Testing of Explosion Technology Sound effect of explosion technology at 30 m distance: 1) Explosion of one joint – 107 dB; 2) Explosion of 3 joints – 115 dB; Remark: for comparison, diesel generator provides at least 110 dB.

VIDEO 7. Demonstration of the Technology for General Specialists of Building Organizations Explosion technology is recommended for industrial application

9. The Influence of the Explosion on Concrete Surface No any damages on the concrete surface are formed in explosion of charge

11. Main Conclusions and Recommendations for Application of New Explosion Technology 1) The explosion technology does not require the use of special equipment, power supply sources and may be used in field conditions. 2) The explosion technology provides high productivity due to preparation of charges together with sleeves in advance and possibility of several joints being done by one shot. 3) Absence of high-temperature heating makes technology effective for connecting of the thermo strengthened armature. 4) The explosion technology may be widely applied during erection or repairing of different building objects such as bridges, hydro stations etc.