Category: Civil 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…

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…

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:  …

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…

What are the Design Loads of Spread Foundation? Prior to the design of a foundation, the expected loads to the foundation should be assessed as accurately as possible, this loads is called design load. In general a foundation has to bear the design load. Various design load of spread foundation are described below. Dead load – This includes the weight of all permanently materials to the structure. This includes beams, floors, walls, columns and fixed service equipment. Live load – All loads which are movable from one location of the…