1.DO A GABLE ROOF(OR IT THERE A GABLE ROOF MODEL?)

A simple gable roof can be made combining existing roof models - and there are more in SF 3D models: roof.

2.TO HAVE A STRAINGTH COLUMN MODEL(THE RED FENCE POST

You can use a cylinder or a box and resize. Some more gates and fences in SF 3D models 317 too - in addition to what you can find with a search like: 3D warehouse: fences.