Post-tensioned insulated wall panels
An insulated concrete panel having one or more tendons positioned in the insulation layer inside the panel which are put into tension after the concrete panel has been formed.
1. An insulated concrete panel, comprising:
(a) a first concrete layer;
(b) a second concrete layer spaced apart from the first concrete layer;
(c) an insulation layer;
(d) a plurality of connectors interconnecting the two concrete layers through the insulation layer and transmitting structural forces between the two concrete layers to provide composite characteristics to the wall panel, wherein the connectors are located wholly within the concrete layers; and
(e) a post-tensioning tendon assembly extending generally within the panel length and positioned between the two concrete layers and embedded in the insulation.
2. A panel as defined in claim 1 , wherein the post-tensioning tendon assembly comprises:
(a) a longitudinal element extending over the majority of the panel length;
(b) anchorage members interconnecting the concrete layers with the longitudinal element for transferring a post-tensioning force from the longitudinal element to the concrete layers.
3. A panel as defined in claim 2 , wherein the longitudinal element is comprised of a high-strength rod, strand, or bar.
4. A panel as defined in claim 2 , wherein the longitudinal element is placed in a space formed in the insulation layer.
5. A panel as defined in claim 2 , wherein the longitudinal element is adjusted to produce tension in the longitudinal element and compression in the concrete layers.
6. A method for constructing an insulated concrete panel, comprising the steps of:
(a) placing a first layer of plastic concrete;
(b) placing a layer of insulation on the first concrete layer;
(c) inserting a plurality of connectors through the insulation layer into the first concrete layer such that the connectors are embedded into the first concrete layer while the concrete is plastic;
(d) positioning a post-tensioning tendon in the insulation layer;
(e) placing a second concrete layer on the insulation layer and consolidated around exposed end portions of the plurality of connectors;
(f) positioning in the concrete layers a pair of anchor plates a predetermined distance apart;
(g) allowing the concrete layers to gain strength through curing; and
(h) adjusting the post-tensioning tendon to produce a force in the tendon and in the concrete layers.
7. A method as defined in claim 6 , wherein the post-tensioning tendon comprises a high-strength longitudinal element and wherein the adjusting step comprises adjusting an end portion of the longitudinal element.
8. A method as defined in claim 7 , wherein adjusting of the end portion of the longitudinal element produces tension in the longitudinal element and compression in the concrete layers.
9. A method as defined in claim 6 , wherein positioning of the post-tensioning tendon occurs while the first concrete layer is still plastic or after the concrete has hardened.
10. The insulated concrete panel of claim 1 , wherein the connectors have a low thermal conductivity.