A connector referred to herein as a knife plate, and the structural connections formed using the knife plate. The knife plate may have a first portion configured to affix to a first structural member, such as a vertical column. The knife plate may have a second portion configured to fit within a slot formed in a second structural member, such as a horizontal beam. The second structural member may be pinned to the knife plate using one or more dowels fit through the second structural member and the knife plate.

A connector referred to herein as a knife plate, and the structural connections formed using the knife plate. The knife plate may have a first portion configured to affix to a first structural member, such as a vertical column. The knife plate may have a second portion configured to fit within a slot formed in a second structural member, such as a horizontal beam. The second structural member may be pinned to the knife plate using one or more dowels fit through the second structural member and the knife plate.

A method and apparatus according to which a blast resistant shelter is assembled. The blast resistant shelter includes first and second structural members, a third structural member coupled to the first and second structural members, a first airway adjacent the third structural member, and a first blast panel pivotably mounted to the third structural member and adapted to pivot thereabout in response to a blast wave. In a first configuration, the first blast panel is detachably connected to a first portion of the blast resistant shelter and prevented from pivoting about the third structural member so that the first blast panel obstructs air flow through the first airway. In a second configuration, in response to the blast wave, the first blast panel is detached from the first portion of the blast resistant shelter and permitted to pivot about the third structural member to permit air flow through the first airway.

A method and apparatus according to which a blast resistant shelter is assembled. The blast resistant shelter includes first and second structural members, a third structural member coupled to the first and second structural members, a first airway adjacent the third structural member, and a first blast panel pivotably mounted to the third structural member and adapted to pivot thereabout in response to a blast wave. In a first configuration, the first blast panel is detachably connected to a first portion of the blast resistant shelter and prevented from pivoting about the third structural member so that the first blast panel obstructs air flow through the first airway. In a second configuration, in response to the blast wave, the first blast panel is detached from the first portion of the blast resistant shelter and permitted to pivot about the third structural member to permit air flow through the first airway.

At least some embodiments of the present disclosure provide a roofing accessory that includes a radiofrequency radiation shielding non-woven fiber composite material. The radiofrequency shielding non-woven fiber composite material includes a first fiber type that includes a conductive material, where the radiofrequency shielding non-woven fiber composite material has a sufficient amount of the first fiber type so as to result, when the radiofrequency shielding non-woven fiber composite material is positioned on a roof structure, in the radiofrequency shielding non-woven fiber composite material allowing for shielding a predetermined percentage of electromagnetic radiation passing through the roof structure. The radiofrequency shielding non-woven fiber composite material includes a second fiber type that includes a non-conductive material. The first fiber type and the second fiber type are randomly dispersed within the radiofrequency shielding non-woven fiber composite.

The object of the invention relates to a neutron absorbing concrete wall (10), which concrete wall (10) has an internal delimiting surface (11a), and an external delimiting surface (11b) on an opposite side to the internal delimiting surface (11a), the essence of which is that it contains a first concrete layer (13a) on the side of the internal delimiting surface (11a), and a second concrete layer (13b) on the side of the external delimiting surface (11b), which first concrete layer (13a) contains at least 0.05 mass % boron-10 isotope (10B), and the second concrete layer (13b) is formed as heavyweight concrete. The object of the invention also relates to a method for creating a neutron radiation absorbing concrete wall (10) that has an internal delimiting surface (11a), and an external delimiting surface (11b) on an opposite side to the internal delimiting surface (11a), the essence of which is a first concrete layer (13a) containing at least 0.05 mass % boron-10 isotope (.sup.10B) is formed on the side of the internal delimiting surface (11a), and a second concrete layer (13b) created as heavyweight concrete is formed on the side of the external delimiting surface (11b). The object of the invention also relates to a neutron absorbing concrete wall (10), the essence of which is that it is formed as heavyweight concrete containing at least 0.05 mass % boron-10 isotope (.sup.10B).

The object of the invention relates to a neutron absorbing concrete wall (10), which concrete wall (10) has an internal delimiting surface (11a), and an external delimiting surface (11b) on an opposite side to the internal delimiting surface (11a), the essence of which is that it contains a first concrete layer (13a) on the side of the internal delimiting surface (11a), and a second concrete layer (13b) on the side of the external delimiting surface (11b), which first concrete layer (13a) contains at least 0.05 mass % boron-10 isotope (10B), and the second concrete layer (13b) is formed as heavyweight concrete. The object of the invention also relates to a method for creating a neutron radiation absorbing concrete wall (10) that has an internal delimiting surface (11a), and an external delimiting surface (11b) on an opposite side to the internal delimiting surface (11a), the essence of which is a first concrete layer (13a) containing at least 0.05 mass % boron-10 isotope (.sup.10B) is formed on the side of the internal delimiting surface (11a), and a second concrete layer (13b) created as heavyweight concrete is formed on the side of the external delimiting surface (11b). The object of the invention also relates to a neutron absorbing concrete wall (10), the essence of which is that it is formed as heavyweight concrete containing at least 0.05 mass % boron-10 isotope (.sup.10B).

In some implementations, a conductive concrete composition for providing improved shielding against electromagnetic radiation comprises cement, one or more supplementary materials, aggregates, one or more carbon products, and fibers. In some implementations, the composition comprises between about 5% and about 40% by weight of cement, between about 1% and about 20% by weight of one or more supplementary materials, between about 5% and about 80% by weight of aggregates, between about 1% and about 40% by weight of one or more carbon products, and between about 1% and about 10% by weight of fibers. In some embodiments, the one or more supplementary materials comprises ground granulated blast furnace slag (GGBS), the one or more carbon products comprises graphite, and the fibers comprise steel fibers. The aggregates can include normal weight, lightweight, and/or fine aggregates.

In some implementations, a conductive concrete composition for providing improved shielding against electromagnetic radiation comprises cement, one or more supplementary materials, aggregates, one or more carbon products, and fibers. In some implementations, the composition comprises between about 5% and about 40% by weight of cement, between about 1% and about 20% by weight of one or more supplementary materials, between about 5% and about 80% by weight of aggregates, between about 1% and about 40% by weight of one or more carbon products, and between about 1% and about 10% by weight of fibers. In some embodiments, the one or more supplementary materials comprises ground granulated blast furnace slag (GGBS), the one or more carbon products comprises graphite, and the fibers comprise steel fibers. The aggregates can include normal weight, lightweight, and/or fine aggregates.

Electromagnetically shielded and self-supporting panels form a shielded enclosure. The use of prefabricated, shielded and self-supporting panels to construct an enclosure reduces the time and cost of constructing such an enclosure.