Piling Hammer | Types of piling hammer

Engineeering Projects
operation of pile hammer

Piles are driven into the ground by means of hammer. Piling Hammer are classified into following types as shown in Fig.1 Drop hammer Single acting hammer Double acting hammer Diesel hammer Vibratory hammer Drop hammer – A drop hammer is lifted up by rope and dropped freely on the pile head. During the driving operation, a cap is fixed to the top of the pile and a cushion is provided in between the pile and the cap. Single acting hammer – In a single acting hammer, a hammer is lifted…

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Proportional Footing for Equal Settlement

Engineeering Projects

Introduction to Proportional Footing for Equal Settlement To reduce the differential settlement due to live load variations for footings on grained soils, it is desirable to proportion all the footings in such a way that they have equal pressures under the service loads. Thus all footings would settle by equal amounts and the differential settlement would be considerably reduced. Steps on proportioning footing for equal settlement as suggested by Peck et al (1974) Determine dead load of footing. Determine the footing subjected to maximum live load. Compute the ratio of…

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Spread Foundation Design Steps

Engineeering Projects

What are the steps used in spread foundation design? Following are the steps used in spread foundation design. Estimate dead load, live load and other loads before spread foundation design. Estimate service load I.e. service load = DL + LL/2. Decide on depth of foundation. Assume dimension of the foundation. Find plan area. Find net load bearing capacity. Estimate allowable bearing capacity. Ensure allowable bearing capacity is equal to or greater than the loading intensity. If not revise the dimension of the footings, compute the net safe bearing capacity. Determine…

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Footing settlement of Spread Foundation

Engineeering Projects
Foundation on stiff strara overlying soft strata

Introduction of Footing settlement of Spread Foundation The footings settlement on sands is determined from the results of plate load tests or penetration tests. The footing settlement computation from plate load tests has already been posted. The computation of footing settlement in sand from the results of penetration is not introduced in this level. (a) Foundation in non-homogeneous strata Soft Soil Overlying Firm Strata – If a foundation is to be laid on a soft strata overlying on a firm strata, the feasibility of the foundation is to be assessed. Safe…

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Power Backup Circuit For Digital Clocks

Engineeering Projects
power backup for digital clock

The usual method of using a 9V battery for backup in digital clocks, though common, is not very desirable for many reasons. The cost of the battery and the very short life are some of them. Circuit Description of Power Back-up Circuit for Digital Clock The circuit described here is a Power backup Circuit for a digital clock and it enables us to get the required 9V from just two penlight cells. Initially one has to invest in this circuit power backup for a digital clock, in the long run,…

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Analogue Frequency Meter with Over-range Indicator

Engineeering Projects
analog frequency meter

The versatile IC timer 555 has yet another application as an analog frequency meter. By making use of a 556 integrated circuit, which has two 555 timers in a single package, an over-range indicator can be economically added to the meter. Circuit Description of Analogue Frequency Meter with Over-range Indicator When this meter is switched to the 50Hz range, any input frequency from near DC to 50 Hz produces a correct panel meter reading, i.e. a frequency of 42 Hz produces a meter reading of 42 microamperes. However, the analog…

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Secondary Settlement of Spread Foundation

Engineeering Projects

What is Secondary Settlement of Spread Foundation? The secondary settlement takes place under constant effective stress. When consolidation is completed, the adsorbed water is drained out and plastic readjustments of soil particles occur. Consequently the soil mass is settled down. Secondary  settlement is also negligible as compared to consolidation settlement. Settlement of Footing in Clay The total settlement is given by: Where s is the total settlement, si is the immediate settlement, sc is the consolidation settlement and ss is the secondary settlement. The secondary settlement is given by:  …

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Consolidation Settlement of Spread Foundation

Engineeering Projects
consolidation settlement formula 1

What is Consolidation Settlement of Spread Foundation? Consolidation settlement is caused due to the expulsion of pore water from the voids of a saturated soil mass under the prevailing excess hydrostatic pressure induced by load imposed on a foundation. Settlement of Footing in Clay The total settlement is given by: Where s is the total settlement, si is the immediate settlement, sc is the consolidation settlement and ss is the secondary settlement, The consolidation settlement is given by: =    ———- (1) For normally consolidated clay, the consolidation settlement is…

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Immediate Settlement | Calculation of Immediate Settlement

Engineeering Projects
fox's correction

Immediate settlement takes place in a short time (about a week) after the application of load and is due to elastic distortion of the soil. As the settlement is experienced in a short time, there will not be enough time for soil mass to change in its water content. Hence, Settlement takes place under constant Volume or under un-drained conditions. Immediate settlement is computed by elastic theory. Compared to consolidation settlement, particularly in saturated clay, immediate settlement is very small and often neglected unless the structure is very important. Settlement…

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Allowable Bearing Pressure

Engineeering Projects

What are the allowable bearing pressure of spread foundation? Footing on Granular Soil | Allowable Bearing Pressure In cohesion less soil, the allowable bearing pressure is governed by allowable settlement. The allowable bearing pressure in sands is governed by shear failure criteria only when the footing is very narrow and below water table and the sand is loose. In sands, obtaining undisturbed sample is difficult even not impossible. Laboratory preparation of sand samples will not simulate the stress – strain relationship pertaining to situation in a representative manner. The effects of…

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