Laserfiche WebLink
Damage <br />Cosmetic or hairline cracks 0.01 to 0.10 mm wide appeared <br />during construction of the house, and also during a period when no <br />blasting was taking place. The formation of cosmetic cracks <br />increased from 0.3 to 1.0 cracks per week when ground motions <br />exceeded 1.0 inch per second.. Human activity and changes in <br />temperature were equivalent to those produced by ground motions up <br />to 1.2 inches per second. <br />When the entire house was shaken mechanically, the first cracks <br />appeared after 56,000 cycles, the equivalent.of 28 years of blast <br />generated ground motions of 0.5 inches per second, twice a day. <br />If blasting occurred only once a day, this would be.equivalent <br />to a period of 56 years; if blasting was only once a week, then it <br />would equate to blasting for a period of 392 years! <br /> <br />Activity <br />Locationl Induced strain <br />(win/in) or Ground vibration equivalency, <br />(in/s) <br /> structure <br />motion (in/s) <br />Envelope2 <br />Regression line3 <br />Walking....... A4, low corner, 0.16 in/s..... 0.07 0.29 <br /> south wall. <br /> A4, low corner, 0.039 in/s.... .005 .07 <br /> east wall. <br /> S2.. ......... 9.1 win/in... .03 .09 <br />Heel drop..... A4, low corner, 0.14 in/s .... .06 .24 <br /> south wall. <br /> A2, midwall... 0.65 in/s..... .06 .17 <br /> S2. ........ 20 win/in.... .03 .20 <br />Low jump..... A4, low corner, 0.12-in/s..... .05 .18 <br /> south wall. <br /> A2, midwall... 1.8 in/s..... .26 .92 <br />High jump..... A4, low corner, 0.31 in/s..... .29 ,74 <br /> south wall. <br /> A2, midwall... 1.2 in/s...... .15 .52 <br /> S2. ......... 42 win/in.... .28 .62 <br />Entrance door A4, low corner, 0.18 in/s..... .09 .22 <br />slam. east wall. <br /> A3, midwall... 1.3 in/s...... .13 .52 <br /> S8...... ..... 21 win/in.. .27 .60 <br />Sliding glass Al, high corner, .87 in/s...... .51 .90 <br />door slam. east wall. <br /> S1. ........ 48.8 win/in.. .50 1.40 <br />Sinking nails A4, low corner, 0.51 in/s..... .38 .80 <br />for pictures east wall. <br /> AS. low corner, 0.67 in/s..... .59 ,89 <br /> west wall. <br /> A2, midwall... 3.9 in/s...... .92 2.16 <br /> S1............ 21 win/in.... .18 .41 <br /> S8............ 32 win/in.... .38 .87 <br /> S12........... 88.7 win/in.. .88 1.44 <br />'From figure 13. <br />28ased on envelope of strain or structure motion versus ground vibration <br />data. <br />Based on regression line through strain or structure motion versus ground <br />vibration data. <br />Table 3 <br />Human activities and equivalent ground vibration levels. <br />33