Prestressed plastic bodies and method of making same
OwnerWilliam A. Jacobsinventor
Life of this patent
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Abstract
A method of producing a compressive stress in a mass comprised of plastic material having a tendon therein, at least a portion of the length of the tendon being contained in thermoplastic material within the mass, the method comprising the steps of heating the tendon to a temperature sufficient to soften the thermoplastic material in an annular region surrounding the tendon, applying a tractive force to the heated tendon, thereby placing the heated tendon under tensile stress, and securing the heated tendon to the mass in a manner that causes the tensile force in the tendon to produce a compressive stress in the mass and prestressed plastic bodies produced according to this method.
Claims14
A method of producing a compressive stress in a mass comprised of plastic material having a tendon therein, at least a portion of the length of the tendon being contained in sulfur concrete within the mass, the method comprising the steps of:
- heating the tendon to a temperature sufficient to melt the sulfur concrete in an annular region surrounding the tendon, thereby creating a melt zone,
- controlling the heating of the tendon so that the annular thickness of the melt zone does not exceed one-half the mean lateral dimension of the large aggregate in the sulfur concrete surrounding the tendon,
- applying a tractive force to the heated tendon, thereby placing the heated tendon under tensile stress, until the tensile stress of the tendon reaches approximately 80% of the yield stress of the tendon and
- securing the heated tendon to the mass in a manner that causes the tensile force in the tendon to produce a compressive stress in the mass.
A tension element for prestressing a mass of plastic material, the element comprising an elongate tendon encased in a solid mantle of sulfur concrete, the lateral surface of the mantle having tension transmitting means thereon comprising corrugations or irregularities in the lateral surface of the mantle resulting from the presence of aggregate for transmitting the tensile force in the tendon to the mass, the sulfur concrete of the mantle having a melting temperature substantially less than the melting temperature of the tendon such that when the tendon is heated to a temperature in excess of the melting temperature of the sulfur concrete of the mantle, the mantle softens in an annular region surrounding the tendon thereby permitting the tendon to move freely in the axial direction with respect to the tension transmitting means.
A prestressed plastic body comprising sulfur concrete and a tension element comprising a tendon, the tendon being encased in a solid mantle of sulfur conrete, the lateral surface of the mantle having tension transmitting means thereon comprising corrugations or irregularities in the lateral surface of the mantle resulting from the presence of aggregate for transmitting the tensile force in the tendon to the mass, the sulfur concrete of the mantle having a melting temperature substantially less than the melting temperature of the tendon such that when the tendon is heated to a temperature in excess of the melting temperature of the sulfur concrete of the mantle, the mantle softens in an annular region surrounding the tendon thereby permitting the tendon to move freely in the axial direction with respect to the tension transmitting means, the tendon being under a tensile stress in excess of eighty percent of the yield stress of the tendon.
Dependencies are inferred from the claim text.