Prestressing and prestressed road pavements
OwnerJohann J. Rieveinventor
Life of this patent
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Abstract
This invention provides for an apparatus and method for prestressing concrete. The apparatus includes a tendon with a tensionable peripheral member and core members that can be releasably latched against the peripheral member in tension or compression. Methods are provided for constructing prestressed concrete slabs for joining the slabs to form a prestressed concrete pavement.
Claims14
An apparatus for prestressing concrete,
- comprising in combination,
- a tendon comprising at lease one elongated tensionable peripheral member defining an enclosure structure open at least at one end, and at least two elongated core members disposed in said enclosure structure;
- first latching means including a part mounted on at least one of said core members and being capable of latching said core member relative to said peripheral member when a compressive force is applied to said core member, whereby, when a compressive force latches said core member relative to said peripheral member, said peripheral member is put into a state of tension, the concrete is placed on said tendon, and upon release of said tensile and compressive forces, said concrete will be prestressed:
- second latching means mounted on at least two of said core members capable of latching said core members relative to said peripheral member, in a state of tension, when differential tensile force is applied to said core members;
- whereby after the concrete has set, the concrete will be post-tensioned;
- said first and second latching means being slidable along with said core members within said peripheral member when unlatched.
In a method for constructing prestressed concrete slabs, utilizing longitudinal tendons having two ends and comprising at least one longitudinal peripheral member which defines a hollow space containing at least two longitudinal core members and force generating means for applying tension and compression to said members,
- the steps comprising,
- (a) placing at least one tendon on a subbase;
- (b) attaching said force generating means to at least one end of said tendon, so as to engage said peripheral member and at lease one core member;
- (c) pulling with said force generating means on said peripheral member;
- (d) pushing with said force generating means at least one of said core members;
- (e) simultaneously releasably latching said core member to said peripheral member;
- (f) thereby maintaining said core member in a state of compression and said peripheral member in a state of tension;
- (g) thereafter pouring concrete so as to form a concrete slab;
- (h) subsequently, after the concrete has set, releasing said pulling and pushing force application, thereby prestressing the concrete slab;
- (i) thereafter pulling on at least one of said core members;
- (j) simultaneously releasably latching said core members to said peripheral member, so as to maintain said core members in a state of tension, thereby post-tensioning the concrete slab;
- (k) thereafter releasing said pulling force application;
- (l) extending said peripheral member by affixing an additional length to the end of the peripheral member;
- (m) sliding said core member within said interconnected peripheral members, so as to position said first and second latching means for the exertion of compression and tension;
- and
- (n) repeating steps (b) through (m), until a desired length of slabs is constructed.
A prestressed concrete pavement comprising in combination:
- a plurality of prestressed concrete intermediate slabs and two prestressed concrete end slabs, at least one gap being defined between adjoining slabs, concrete being disposed and prestressed in said gap;
- each of said slabs having at least one peripheral member, the peripheral member of each slab defining an enclosure structure, and being aligned with, and connected to, a corresponding peripheral member of a neighboring slab,
- each peripheral member of said intermediate slabs being grout-filled, the peripheral member of at least one of said end slabs includes at least one tensionable core member, whereby said end slab may be post-tensioned by said core member.
In a method for constructing a concrete pavement including a plurality of adjoining prestressed concrete slabs sequentially arranged, including a first slab and a last slab, each concrete slab being spaced apart from an adjoining slab by a gap adequate for the positioning and operation of a jack, there being a plurality of sequential gaps including a first gap and a last gap, wherein each slab contains at least one tendon, said tendon of each slab being substantially aligned with the tendon of the adjoining slab, said tendon including at least one elongated tensionable peripheral member defining an enclosure structure open at least at one end and at least two tensionable elongated core members disposed in said enclosure structure,
- the steps comprising:
- (a) inserting a jack into sequential gaps, including at least the first of said sequential gaps;
- (b) pushing with said jack against corresponding adjoining slabs so as to put said slabs in a state of compression;
- (c) removing said core members from the first concrete slab;
- (d) interconnecting the peripheral members of the slabs adjoining said first gap;
- (e) placing concrete in said first gap;
- (f) removing the jack present in the first in the sequence of said sequential gaps thereby prestressing the concrete in said first gap;
- (g) placing the removed jack in the next sequentially available gap;
- (h) adjusting each of said jacks in said gaps so as to exert a pushing force on said slabs adequate for compressing said slabs without displacing said slab;
- (i) removing the core members from the concrete slab sequential to said concrete-filled gap;
- (j) interconnecting the peripheral members of the slabs adjoining the gap sequential to said concrete-filled gap;
- (k) placing concrete in said sequential gap;
- (l) removing the jack from said successive gap thereby prestressing the concrete in said gap;
- (m) repeating steps g-l until all remaining sequential gaps are filled with jacks;
- (n) repeating steps h-l until one jack remains in the last gap;
- (o) adjust said jack in said last gap so as to exert a pushing force on said adjoining slabs adequate for compressing said adjoining slabs without displacing them;
- (p) interconnecting the peripheral members of the slabs adjoining said last gap;
- (q) placing concrete in said last gap;
- and
- (r) post-tensioning said last concrete slab by pulling on said tensionable core members present in said last slab.
Dependencies are inferred from the claim text.