12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaVelocity (mm/s)600 mm below surface, vehicle speed 40 km/hover the test area. At next instant it is squeezedtogether approximately 0.07 mm at the same time asthe blue curve indicates that the pipe goes eccentricapproximately 0.04 mm.0,120,100,08Side (mm)Up (mm)0,06Down(mm)Time (s)Fig. 17 Vibration velocity 600 mm below the road surfacewhen lorry passes at 40 km/h.mm0,040,020,00-0,02-0,04-0,060,00 1,00 2,00 3,00 4,00time (s)Fig. 20 Instant deformation 200 mm below the roadsurface when lorry passes at 40 km/h.3.3 Test results from radial and axial stiffness ofthe pipeThe test pipe was compressed 1.8 mm two times with afeed speed of 1 mm/min. In Fig. 21 it can be seen thatthe maximum force at 1.8 mm turned out to be 1.4 kN.Fig. 18 Maximum amplitude of acceleration as a functionof speed.Using this result to look at what the correspondingforces should be in the test when a heavy lorry passesover the test area (see Fig. 20) it can be establishedthat the instant forces from passing vehicles is small.1600140012001000Load, N800600400Test 1200Test 200 0,5 1 1,5 2Fig. 19 Maximum amplitude of vibration velocity as afunction of speedDeformation, mmFig. 21 Diagram radial stiffness of a casaflex pipe.Feed speed 3 mm/minThe acceleration of the ground increases with thespeed of the traffic. And the effect is more sensitive thecloser you are to the surface (see Fig. 18).201816Load case (a)The vibration velocity also increase with the speed ofthe traffic. The effect is not as sensitive as for theacceleration when it comes to the coverage (seeFig. 19).Axial load, kN141210864Load case (c)Load case (b)In Fig. 20 the diagram describes the instantdeformations in the test pipe when the heavy lorrypasses over the test area at a speed of 40 km/h. It canbe seen from the red and the violet curves that the pipecasing is squeezed together approximately 0.17 mmfrom top to bottom at the instant when the lorry passes200 0,5 1 1,5 2Axiell compression %Fig. 22 Axial stiffness of a casaflex pipe101