الاخبار

رسالة ماجستير / علي هادي

   
71 مشاهدة   |   0 تقييم
تحديث   25/10/2020 9:53 صباحا

Abstract  

   This  study investigates  the reduction of vibration effect between two footings by placing a trench between them . The first footing (designated  as the source footing ), on electric-rotary motor is fitted , it has dimension of (100x100)  mm. Beside the source footing a second footing is placed and on this footing the reduction in vibration effects are to be investigated . Both the source footing , nearby footing and trench are placed over compacted gypseous soil in a steel tank having  gypsum contents  with  (50%) .  Single  type  of footing  is investigated, a  square footing with dimensions  (80x80)  mm. Tests are performed under dry and soaking conditions. The footing is loaded  with static weight, while the source footing is with its self-weight. The experimental work is carried out taking the following parameters into observance: types of materials  that it is used to fill the trench (PPR pipe with SBR rubber, SBR rubber, low density polyethylene  and styropor) as for dimensions of  the trench two depths for the trench are  used (B and 2B  when B is width of footing equal 80mm), and operating frequency of the mechanical oscillator.

     Forty-eight tests are carried out for square shape foundation, under three operating frequencies namely, 8, 14, and 20 Hz. The spacing (S) between the footing and trench is ( S=2B) and the spacing(S) between the source of vibration and trench is(S=3B), as for dimensions of trench as follows (length=3B, width= 0.5B and depth=B, 2B). Displacement amplitude, velocity, acceleration and settlement of footing  are measured during tests.

    The reduction in displacement amplitude for  footing when the depth of trench (depth=B) at frequency of 8 Hz is (91 % and 67 %) at dry state in each techniques (PPR with SBR and XPS)  gradually, and (100 % and 70 %) at soaking state ,as for frequency of 20 Hz at same depth is (68 % and  60 %) at dry state in (PPR with SBR and XPS) gradually and (47 % and 30%) at soaking state. But at same frequency for depth of trench (depth=2B) is (84 % and 53 %) at dry state and (70 % and 1%) at soaking state.

      The reduction in settlement value for footing when the depth of trench (depth=B) at frequency of 8 Hz is (85 % and 15%) at dry state in each techniques (PPR with SBR and XPS)  respectively, and (70 % and 25%) at soaking state.  As for frequency of 20 Hz at same depth is (58%  and 45 %) at dry state and (60  and 5%) at soaking state in all from (PPR with SBR and XPS )  respectively. But at same frequency for depth of trench ( depth=2B) is (65 %) at dry state and (67%) at soaking state in (PPR with SBR). As for Styropor, it is give negative results.

 




العنوان / ديالى / بعقوبة / طريق بغداد بعقوبة القديم / المرادية جميع الحقوق محفوظة للمكتبة المركزية جامعة ديالى
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