استكمالا لما بدا به استذنا في تنفيذ الاوتاد المهندس محمد زايد اقدم لكم طريقة فحص التحميل للاوتاد الخرسانية بواسطة O- Cell والكلمة اختصارا Osterberg Cellوهي على اسم مخترعها.
ويتم تركيب الخلية o -cell في وسط الوتد ويتم تركيب صفيحة معدنية bearing plate في نهاية الوتد.
تستخدم هذه الطريقة في الاحمال الكبيرة
O-cell is a hydraulically driven, high capacity, sacrificial loading device installed within the foundation unit. As the load is applied to the O-cell, it begins working in two directions; upward against upper side shear and downward against base resistance and lower side shear (if applicable).The O-cell Advantages
By virtue of its installation within the foundation member, the Osterberg Cell load test is not restricted by overhead structural beams and tie-down piles. Instead, the O-cell derives all reaction from the soil and/or rock system. End bearing provides reaction for the skin friction portion of the O-cell load test, and skin friction provides reaction for the end bearing portion of the test. Load testing with the O-cell continues until one of three things occurs: ultimate skin friction capacity is reached, ultimate end bearing capacity is reached, or the maximum O-cell capacity is reached.
Each Osterberg Cell is specially instrumented to allow for direct measurement of expansion, along with compression and top of pile shaft measurements, the downward end bearing movement and the upward skin friction movement are known.
O-cells range in capacities from 75 tons (150 kips) to 5,000 tons (10,000 kips). By using multiple O-cells on a single horizontal plane, the available test capacity can be increased to more than 30,000 tons (60,000 kips). By utilizing multiple O-cells on different planes, distinct elements within a shaft or pile can be isolated for testing. Using the O-cell, LOADTEST has elevated the application of deep foundation load testing, from expensive time consuming small scale field tests to state-of-the-art short duration full scale load testing of production
shafts and piles.
DESIGN: Excellent tool for value engineering foundation redesign
HIGH TEST LOAD CAPACITIES: Test loads routinely exceed 27 MN,
however, O-cell test capacities are available from 0.44 MN to greater than 200 MN under suitable conditions
REDUCED WORK AREA: Required work area (overhead and laterally) is greatly reduced vs. any other static load testing system. Testing has been performed inside buildings, under overpasses, in narrow interstate/highway median strips and off-shore
TIME: Testing is performed once concrete has reached suitable strength. (which typically takes 7-14 days from pile installation)
IMPROVED SAFETY: No reaction system is required at ground level and the test energy is safely buried well below ground
ROCK SOCKETS: High test loads can be applied directly on deeply buried rock or soil formations without load shedding in overlaying soils, which eliminates the need for de-bonding techniques
DEEP CUT-OFF LEVELS: O-cell testing with deep cut-off levels below ground can be performed; eliminating pile extensions to ground level and pile head preparations
PILES WITH PLUNGE COLUMNS: Where steel columns have been cast in the top of the pile, these often interfere with top-down testing techniques, and the O-cell testing method is likely to be the only cost effective way of performing a full scale static load tests on these piles
ACCURACY: Since there are no anchors, reaction piles or a reaction mass required, the influences, in terms of modified test pile performance, resulting from the construction and the use of anchors, reaction piles or a reaction mass required in top-down static testing, are eliminated
ECONOMY: The O-cell method becomes more economical as loads increase, unlike top-down static tests
SHEAR / END BEARING COMPONENTS: The O-cell tests are designed to separate test piles into 2 or 3 pile sections; thus automatically measuring the reaction of each of the component
AUTOMATION / STATIC CREEP EFFECTS: The O-cell test is a static maintained load test and uses automatic data acquisition techniques and load maintenance for accurate, efficient data processing and creep measurements
PRODUCTION PILES: Post-test grouting techniques allow for testing of production piles
PERFORMANCE: The subsequent performance of O-cell tested production piles will be similar to the non-tested production piles due to the lower amount of generated residual stresses in the pile, as compared to applying full test loads "top-down."
OFF-SHORE: The O-cell test method particularly excels in off-shore testing environments due to its numerous advantages illustrated above
واليكم عدد من الصور من الموقع
لاحظ صفيحة التحميل في نهاية الوتد end bearing plate