EFFECT OF BLAST LOAD ON BEHAVIOUR OF REINFORCED CONCRETE STRUCTURE
Ahmed Khedr Ahmed Khedr;
Abstract
From the previous discussion, the following conclusions could be made:
1. Using widely used software like ETABS in study effect of blast load on concrete structure provide a conservative response for concrete framing system building and the precast concrete wall panels examined in this study. Table 3.1 and 3.5 showed the comparison between some of analytical model results obtained from programs specialized in the study of the impact of explosion on concrete structures and experimental results with results obtained from ETABS analytical model.
2. Ritz-vector analysis seeks to find modes that are excited by a particular loading. Ritz vectors can provide a better basis than do eigenvectors when used for studying effect of blast load on concrete structure by using time-history analyses that are based on modal superposition. Research has indicated that the natural free-vibration mode shapes are not the best basis for a mode superposition analysis of structures subjected to dynamic loads. It has been demonstrated (Wilson, Yuan, and Dickens, 1982) that dynamic analyses based on a special set of load dependent Ritz-vectors yield more accurate results than the use of the same number of natural mode shapes. The algorithm is detailed in Wilson (1985). The reason the Ritz-vectors yield excellent results is that they are generated by taking into account the spatial distribution of the dynamic loading, whereas the direct use of the natural mode shapes neglects.
3. From discussion the deformation of (L. E. García & M. A. Sozen) analytical model and four precast wall panels were tested under four explosive demands (PCI Daniel P. Jenny Fellowship and Lehigh University) finding that peak displacement occurs during or after the negative pressure phase. Therefore the negative impulse must be included for accurate prediction of deformation. Discounting the negative phase provides an overly conservative estimation of expected deformation. The reason the structural response to blast loading is considerably affected by the ratio of blast load time duration (td) to the natural period of vibration of the structure (tm).
4. Using (TM5-1300) for determination pressure-time blast loading curve for building without front wall opening and have the same Building volume, Front area (360 ft2), Charge weight(5,000 lbs), side wall length(30 ft) and Charge distance(155 ft); the following results obtained:
• Clearing time(tc) is the only parameter changed in value and all other parameters still constants in determination of pressure-time blast loading curve for front wall, due to calculation of (tc) depend on the clearing distance(S) and(R) in which calculation of (S) and (R) depend on the height and width of front wall. Table 4.35 showed the relation of previous parameters for front wall.
1. Using widely used software like ETABS in study effect of blast load on concrete structure provide a conservative response for concrete framing system building and the precast concrete wall panels examined in this study. Table 3.1 and 3.5 showed the comparison between some of analytical model results obtained from programs specialized in the study of the impact of explosion on concrete structures and experimental results with results obtained from ETABS analytical model.
2. Ritz-vector analysis seeks to find modes that are excited by a particular loading. Ritz vectors can provide a better basis than do eigenvectors when used for studying effect of blast load on concrete structure by using time-history analyses that are based on modal superposition. Research has indicated that the natural free-vibration mode shapes are not the best basis for a mode superposition analysis of structures subjected to dynamic loads. It has been demonstrated (Wilson, Yuan, and Dickens, 1982) that dynamic analyses based on a special set of load dependent Ritz-vectors yield more accurate results than the use of the same number of natural mode shapes. The algorithm is detailed in Wilson (1985). The reason the Ritz-vectors yield excellent results is that they are generated by taking into account the spatial distribution of the dynamic loading, whereas the direct use of the natural mode shapes neglects.
3. From discussion the deformation of (L. E. García & M. A. Sozen) analytical model and four precast wall panels were tested under four explosive demands (PCI Daniel P. Jenny Fellowship and Lehigh University) finding that peak displacement occurs during or after the negative pressure phase. Therefore the negative impulse must be included for accurate prediction of deformation. Discounting the negative phase provides an overly conservative estimation of expected deformation. The reason the structural response to blast loading is considerably affected by the ratio of blast load time duration (td) to the natural period of vibration of the structure (tm).
4. Using (TM5-1300) for determination pressure-time blast loading curve for building without front wall opening and have the same Building volume, Front area (360 ft2), Charge weight(5,000 lbs), side wall length(30 ft) and Charge distance(155 ft); the following results obtained:
• Clearing time(tc) is the only parameter changed in value and all other parameters still constants in determination of pressure-time blast loading curve for front wall, due to calculation of (tc) depend on the clearing distance(S) and(R) in which calculation of (S) and (R) depend on the height and width of front wall. Table 4.35 showed the relation of previous parameters for front wall.
Other data
| Title | EFFECT OF BLAST LOAD ON BEHAVIOUR OF REINFORCED CONCRETE STRUCTURE | Other Titles | تأثير أحمال الانفجارات علي سلوك المنشات الخرسانية المسلحة | Authors | Ahmed Khedr Ahmed Khedr | Issue Date | 2013 |
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