Explanation:
When a column is fixed to its footing using foundation bolts, the type of stress induced in the bolts is pure tension. This means that the bolts are subjected to a pulling force along their length.

Reasoning:
To understand why the stress induced in the foundation bolts is pure tension, we need to consider the forces acting on the bolts.

- When a column is fixed to its footing, it is subjected to various loads such as dead loads, live loads, wind loads, etc. These loads are transferred from the column to the footing through the foundation bolts.

- The purpose of the foundation bolts is to securely anchor the column to the footing and prevent it from overturning or shifting. Therefore, the bolts need to be able to resist the tension forces generated by the loads acting on the column.

- The tension forces are transferred from the column to the bolts through the anchor plates or washer plates that are placed between the column base and the footing. These plates distribute the forces evenly across the bolts.

- The tension forces in the bolts are generated due to the fact that the column wants to pull away from the footing. The bolts act like a "tie" that holds the column down and prevents it from lifting or separating from the footing.

- It is important to ensure that the foundation bolts are designed to withstand the tension forces generated by the loads acting on the column. The bolts should have sufficient strength and ductility to resist these forces without breaking or deforming.

- In some cases, the foundation bolts may also be subjected to shear forces if there is a horizontal component of the loads acting on the column. However, the primary type of stress induced in the bolts is pure tension.

Conclusion:
In conclusion, when a column is fixed to its footing using foundation bolts, the type of stress induced in the bolts is pure tension. The bolts are subjected to a pulling force along their length to resist the tension forces generated by the loads acting on the column. It is important to ensure that the bolts are designed to withstand these forces to ensure the stability and integrity of the structure.