The Djed-pillar, Egyptian , is an ancient symbol for stability and endurance. It is mentioned in the Pyramid Texts of the Old Kingdom:
You shall emerge as Horus-of-the-Underworld at the head of those who never set and sit on your metal throne above the your canal belonging to the watery region (of the heavens), living like an ankh-beetle, enduring like a djed-pillar.Pyramid Texts of Pepi I, PT 537 
The djed‘s magic could enhance endurance and stability of persons, institutions like the kingship, and of physical structures. One assumes that the djed-signs engraved on columns were hoped to improve the stability of the building.
A somewhat battered amulet eight centimetres tall, showing a was-sceptre, a djed-pillar and an ankh-sign on top of a neb-basket. Late Period
Source:Petrie Museum website, UC38608
It has been suggested that originally, in the Predynastic Period, the djed was the depiction of a pillar around which sheaves of corn had been tied. Others have proposed that it represented a leafless tree, a pole with notches, was made up of reeds or sheaves of corn, or that, together with the ankh-sign and the was-sceptre with which it was frequently depicted in ornamental freezes, the djed was a fetish of an ancient cattle cult, in which it symbolized the bull’s backbone, the ankh a vertebra and the was the penis. Endurance and stability was often wished for, together with such boons as life, prosperity or power:
Nekhbet, the White One of Nekhen, may she grant life, stability and power like Re.Seti I, Amen temple at Karnak 
It was the Memphite god Tatenen who brought the djed-pillar into this world. Originally Sokar was associated with the Djed-pillar, later Ptah, who merged with Tatenen, became identified with Sokar and received the title of Noble Djed. Ptah was depicted as a mummy holding in his hand a sceptre which combined ankh, djed and was. As early as the Old Kingdom there was a priest of the Noble Djed at Memphis.
Eventually, during the New Kingdom, the djed became a symbol of the Osirian cult and was referred to as the backbone of Osiris in the Book of the Dead. The murder of Osiris by his brother Seth was obliquely referred to as Seth having laid the djed on his side. By raising the djed Horus helped his father to rise from the dead. In coffins there was at times a picture of a djed-pillar painted below the deceased’s back where it could protect his backbone and help in his resurrection. In the Osirian context the djed was at times shown with human arms holding royal insignia of power, this god having been ruler of the world.
A ritual connected with the djed was the raising of the djed-pillar performed by the king at Memphis. The pharaoh himself supported by priests raised the djed-pillar with the help of ropes and the queens their attendants sang hymns. The ceremony celebrated the enduring of the Egyptian kingship and the resurrection connected with the Osirian cult. It symbolized the ultimate victory of Osiris over Seth.
O Thoth, who justifies Osiris against his enemies, justify NN against his enemies in the great Court at Busiris, in that night of the Raising of the Djed-pillar at Busiris.Book of the Dead, Tb 018 
The djed was connected with fertility and conserved the fruitfulness of the grain. The festival of the Raising of the Djed took place on the first day of Shemu, the ritual harvest season. People came to venerate the Djed and then reenacted the mythological battle between good and evil as part of the festivities and oxen were driven around the walls of Memphis.
The Raising of the Djed was also part of the Heb-Sed, the rejuvenation ceremony performed mostly by aging pharaohs at varying intervals, by which their waning powers were to be restored.
Djed amulet, Late Period, Hawara
Source: Petrie Museum web site, cat. no. UC38595
The use of djed amulets was widespread and most mummies were equipped with one. They were made of all sorts of materials, from ivory to gold. Instructions on how to use them can be found in the Book of the Dead for instance:
On shall say this charm over a djed amulet of faience, the engravings of which are (inlaid with) electrum, covered in byssus, while causing unguent to drip over it, tied to a brick of fresh clay.Book of the Dead, Tb 151 
The art of coffin decoration became highly developed during the 21st dynasty, and after its decline by the beginning of the 22nd dynasty beautiful cartonnage cases were being created, which also often showed winged deities and djed-symbols.