BUILDING CONSTRUCTION MATERIALS- 2

TIMBER GRILLAGE

1)Timber grillage foundation is provided for heavily loaded timber column or masonry wall. 2)The foundation uses timber planks and timber beams. 3)This foundation is specially useful in water logged areas where the bearing power of the soil is very low, and where the steel beams may get corroded due to subsoil water. 4)The loading on the soil is limited to 50 to 60 kN/m2. No concrete is embedded between the timber joists.

METHOD OF CONSTRUCTIONWooden planks, usually 5 to 8 cms in thickness are laid

side by side longitudinally on the prepared bed of the trench excavated for the purpose .The planks should be arranged in a width 45 to 60 cms on either side than the designed width of the base course of the structure .

On the bottom layer of planks ,rectangular timber sections of suitable size are laid at about 35 cms center to center .Then the top layer planks of 8 to 10 thickness ,arranged side by side ,in width equal to that of the base course of the structure is to be built over it On timber platform thus prepared ,the structure in the form of timber column or even masonry wall is built

ADVANTAGES

Timber grillage foundation is often found to be lighter and more economical

Easily laid and effectually hold the tops of the piles in place.

They also tend to distribute the pressure evenly over the piles, as the transverse strength of the timber will help to carry the load over a single pile, which for some reason may not have the same bearing capacity as the others.

TIMBER GRILLAGE FOUNDATIONS USED IN FAMOUS STRUCTURES

Auditorium inspired by richardsonian romanesque ,chicago

Chicago was notorious for its wet and unstable soil.

The soil beneath the Auditorium consists of soft blue clay to a depth of over 100 feet, which made the conventional foundations of the 1800s impossible. Dankmar Adler designed the Auditorium’s foundation as a unique configuration of isolated piers, each created to support a portion of the building’s 110,000 tons.

The foundation was made of criss-crossed grillage of timbers and railroad beams encased in concrete.

Brooklyn Bridge new york

Kasthamandap ,MARU KATHMANDU

BY ,DEEPTHI K S PANNAGA KARUR SHAHEEN HUSSAINTEJASWINI KRISHNA P

GROUP 12nd semester ‘C’ RVCA