PURPOSE: To increase the load strength of a structure by bonding plastic strips having plural through holes to each other with a space each other so as to form a honeycomb structure, and filling the inside thereof with concrete and asphalt or the like.
CONSTITUTION: A plastic strip 16 is provided with plural through holes 12. Plural strips 16 are arranged in parallel with each other, and the adjacent strips 16 are bonded 22, 23 to each other with a space each other. The strips 16 are pulled in a direction vertical to the surface of the strip 16 so as to form honeycomb-like cells 14. The cells 14 are filled with concrete, asphalt, sand or the like for use. Shape and number of the through hole 12 are changed in response to the filler. With this structure, structural uniformity is improved so as to increase the strength, and the draining property is improved.