Category: Foundations

As discussed earlier this type of foundation is used when the bearing capacity is low and total area of spread footing exceeds 50% of the total plinth area. Mat foundation consists of rows of columns built monolithic with a continuous slab covering the entire foundation area, with or without depressions or openings. A true mat… Continue reading Construction of Mat Foundation

A wall footing is a typical case of continuous footing. This may have a base course of concrete or may be made of the same material as that used for the wall. This type of footing may be simple or stepped. For light loads a simple base with a projection of 15 cm on either… Continue reading Construction of Continuous Footing

Combined footings are designed keeping the following aspects in view: Other procedure adopted for column footing may be adopted here too.

Spread footing is called as isolated or column footing. They are used to support individual columns. They can be of stepped type or provided with projections in the concrete base. Main reinforcement is placed at the bottom. In case of heavily loaded columns reinforcement is provided in both the directions in the concrete bed. The… Continue reading Construction of Spread Footing

The construction procedure adopted in each of the building foundations are briefly explained below.

Excavation beyond depth of 1.5 m is generally categorised as deep excavation. The problems generally encountered in deep excavation are: Only the first aspect is treated in the sections treated below. The secured aspect is dealt separately elsewhere. Following methods of bracing are commonly employed. 1. Stay Bracing This arrangement is similar to that followed… Continue reading Deep Excavations

Many a times, building sites extend to the edges of the property lines or are adjacent to other sites, over which some structures may already be existing. Under these conditions, it is mandatory that the sides of the excavation must be made vertical and should be usually supported. Several methods are available in such occasions.… Continue reading Shallow Excavations with Sheeting and Bracing

Shallow excavations can be made if there is enough space is available to establish slopes at which the material can stand. As a general rule construction slopes can be made as steep as possible although a few small slides is generally not serious. But the steepness of slope depends on the type of soil or… Continue reading Shallow Excavations with Unsupported Slopes

The foundations for most structures are invariably established below the surface of the ground. Thus they can not be constructed until the soil or rock above the base level of the foundations has been excavated. Open excavations are supported in some soils by lateral support called bracings. It is generally the engineer’s duty to decide… Continue reading EXCAVATION FOR FOUNDATION

Following guidelines may be considered in design of piles Where  = Hammer efficiency W = Weight of hammer h = Height of fall S = Final set  = Efficiency of the blow. C = Sum of the temporary elastic compression of the pile.