Abstract: The invention relates to a light-weight load-bearing structure, reinforced by core elements (2) of a strong material constituting one or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2), where the core (2) is constructed from segments (1) of core elements (2) assembled by means of one or more prestressing elements (4). The invention further relates to a method of casting of light-weight load-bearing structures, reinforced by core elements (2) of a strong material constituting one or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2), where the core (2) is constructed from segments (1) of core elements (2) assembled and hold together by means of one or more prestressing elements (4).

Abstract: A removable arch form assembly for use in forming a masonry arch of a plurality of masonry elements on a substructure comprises a flexible arch form having a substantially rectangular shape, first and second end clips engaging an arched structure about which the masonry arch is to be formed, at least one intermediate clip positioned on the arched structure between the end clips and at an elevation differing from the end clips, the end clips and the at least one intermediate clip removably receiving the flexible arch form and retaining the form in an arched orientation.

Abstract: A three-dimensional constructional element 10 is shown having opposing and substantially planar panels 30, 40 mounted on opposing surfaces of a flexible planar member in the form of a flexible mesh material layer 52 therefore making a composite sheet of three layers. Panel 30 includes transverse grooves 12, 14 formed therein and panel 40 includes transverse grooves 16, 18 formed therein. The structure is deformable about each groove 12, 14, 16, 18. In a preferred embodiment the panels 30, 40 are divided into many segments defined by the transverse grooves to allow the constructional element to be deformed so that one of the exterior surfaces of panel 30 is concave while the opposing exterior surface of panel 40 is convex.

Abstract: A structure assembled from a combination of stackable modules, each module assembled from multiple prefabricated, transportable blocks. The blocks are typically reinforced cast concrete formed in reusable molds. Module framing blocks may include arched corner blocks, key blocks that interlock with a pair of corner blocks, and optional center blocks. Other structural elements include roof, floor, and wall components that interlock with the framing modules. Modules may be stacked or nested to form structures including buildings, elevated roadways, and parking garages. Utilities may be provided through optional conduits formed in the corner elements. The framing supports raised floor modules for ease in mechanical system installation and modification. The roof elements support usable terraces and rainwater collection. The blocks are demountable and reusable. The modules are self-supporting during erection, and may be assembled without fasteners.

Abstract: An architrave support for supporting one or more sections comprises a plurality of planar portions and preferably a base support which together form a preferably self supporting arch-like shaped architrave support. Each planar portion has a pair of opposite oblique ends abutting another said planar portion or the base support. The plurality of planar portions are in series, preferably mitred, at their oblique ends to form the arch-like shaped architrave support. The support may be preformed or in a kit, either together with or separately to corresponding architrave portions for attachment thereto to form an architrave. The support is useful for forming architrave arches above doorways or windows.

Abstract: A flat-formed arch ring unit includes a linear array of voussoir portions connected along their upper edges. The unit is then archable. A method is provided for forming an archway including the steps of arching one or more the flat formed arch ring units and locating them between two or more foundation blocks or the like. This provides a simple yet effective process and unit for forming an archway. With ease of production, shaping and transportation, making new archways or carrying out repairs of existing bridge archways is significantly faster and cheaper, minimizing disruption and delay to traffic.

Abstract: A hybrid arched overfilled structure includes a combination of pre-cast side elements and at least one cast-in-place crown sector element. The side elements are pre-cast generally in a horizontal orientation and subsequently lifted into place. The crown sector element is cast in place between the side elements. In one form of the invention, each of the three sections makes up about one-third of the overall arch span.

Abstract: The top arch overfilled system defined in application Ser. No. 10/102,921 is formed of precast arch elements which are formed and shipped in a use orientation. The precast arch elements can include arch footings and the system can include a plurality of precast arch elements which can be tied together. The arch elements can also be prestressed.

Abstract: A palisade comprises visible or wall surfaces disposed on opposing sides and intermediate end faces. One of the end faces is provided with a projecting convex head, while the other end face comprises a correspondingly formed concave receptacle for the head. When forming a palisade wall, the head of a palisade can engage in the receptacle of a neighboring palisade such that the head substantially completely fills the receptacle. To be able to bend neighboring palisades relative to one another over a large angle and to increase the design possibilities of a palisade wall, the head and the receptacle are disposed eccentrically on the respective end face and preferably in the corner region between the end face and the associated visible or wall surface.

Abstract: A first voussoir for use in an arched structure between second and third voussoirs includes a first end bearing surface with a protrusion which extends from the surface and which is mateable with a corresponding recess in an abutting end bearing surface of the second voussoir. The second end bearing surface includes a recess in the surface which is mateable with a corresponding protrusion in an abutting end bearing surface of the third voussoir. Preferably the protrusions and the recesses have both longitudinal and transverse components of structure. A connector is secured to the first voussoir for connecting one end of an associated tension member to the first voussoir while an opposed end of the tension member is connected to an associated mooring positioned at a distance away from the horizontal span of the arched structure.

Abstract: An earth overfilled arched structure includes a shallow arch spanning a clear space. The sides of the clear space are formed by curved or straight walls. Solidified zones of earth material (backfill or in situ) against the springs of the arch and/or behind the walls form foundation blocks which are in intimate contact via arch footings with the springs of the arch and/or with the upper part of the sidewalls in such a way that the arched structure delivers most or all of its support forces into the foundation blocks. These, due to their size and weight, transfer and spread the support forces to the subsoil so that displacements, especially in the horizontal directions, are minimal.

Abstract: Earthquake resistant blocks or discrete structures are manufactured using pieces of low quality construction materials such as slag, concrete waste, chipped stone, Sirasu, etc. The pieces are placed in a mold and arranged in the mold so that they are in intimate contact with the mold sides and with each other throughout the mold. Once positioned, mortar or other concrete binding material is poured in to retain the low quality construction materials in contact with each other. When the blocks or discrete structures are placed adjacent to each other, such as when constructing arches, they absorb or dissipate the shock and vibration energies by having the sides of the blocks, and in particular the low quality materials within the blocks, in firm frictional contact. The amount of concrete used is greatly reduced and local and normally scrap material can be used and recycled.

Abstract: A three piece concrete culvert system includes a set of horizontally spaced precast side wall sections having inwardly projecting and opposing steps or surfaces which support opposite ends of a precast arched top wall section. The side wall sections include extension portions which project substantially above the ends of the top wall section for increasing the capacity of the side wall sections to resist thrust from the top wall section. Vertically spaced and generally horizontal layers of soil reinforcement members or grids may be positioned within the soil backfilled adjacent the outer surfaces of the side wall sections, and precast concrete anchor members may be attached to the side wall sections above supporting footers for the side wall sections. Shims are used between the footers and the anchor members for temporarily positioning and aligning the side wall sections before receiving the top wall section.

Abstract: An adjustable masonry arch form is disclosed. The adjustable masonry arch form has a planar base section to support the masonry elements which will form the masonry arch, and a plurality of attachment elements secured to the planar base for securing the form to a structure. The adjustable masonry arch form is constructed from material rigid enough to support the masonry elements, but flexible enough to be bent to conform to any given arched construction without unwanted buckling of the form. The masonry elements which form the masonry arch are placed directly on the planar base of the form in the desired configuration and secured in the masonry arch by mortar. The form is left in position permanently, obviating the need to build a temporary arch support saving time and expense and obviating waste of materials.

Abstract: An earth overfilled arched structure includes a shallow arch spanning a clear space. The sides of the clear space are formed by curved or straight walls. Solidified zones of earth material (backfill or in situ) against the springs of the arch and/or behind the walls form foundation blocks which are in intimate contact via arch footings with the springs of the arch and/or with the upper part of the sidewalls in such a way that the arched structure delivers most or all of its support forces into the foundation blocks. These, due to their size and weight, transfer and spread the support forces to the subsoil so that displacements, especially in the horizontal directions, are minimal.

Abstract: A hybrid arched overfilled structure includes a combination of pre-cast side elements and at least one cast-in-place crown sector element. The side elements are pre-cast generally in a horizontal orientation and subsequently lifted into place. The crown sector element is cast in place between the side elements. In one form of the invention, each of the three sections makes up about one-third of the overall arch span.

Abstract: A first voussoir for use in an arched structure between second and third voussoirs includes a first end bearing surface with a protrusion which extends from the surface and which is mateable with a corresponding recess in an abutting end bearing surface of the second voussoir. The second end bearing surface includes a recess in the surface which is mateable with a corresponding protrusion in an abutting end bearing surface of the third voussoir. Preferably the protrusions and the recesses have both longitudinal and transverse components of structure. A connector is secured to the first voussoir for connecting one end of an associated tension member to the first voussoir while an opposed end of the tension member is connected to an associated mooring positioned at a distance away from the horizontal span of the arched structure.

Abstract: Shelters as shown in FIG. 3, are constructed by filled bags (1), which typically have a trapezoidal cross-section. Such bags are divided into several compartments by internal webs (3) and can be laid over an arched lining (2). In end view, the bags are slightly wedge-shaped so that they resemble stones following the curve of a masonry arch, and the webs (3) follow the curve of the arch so that there is an inner compartment (4), a middle compartment (5), and an outer compartment (6) in each bag. In addition to shelters, the bags can be used to build barriers formed of courses of bags, with at least one side of the barrier having a corbelled out portion.

Abstract: A hub assembly for pivotally connecting the ends of support rods of a portable self-supporting display structure configured for a collapsed storage position and an expanded display position. The hub assembly may include first and second members and a connector. The first and second members are mated to provide bearing surfaces and to accommodate pivot pins affixed to the support rods. The connector secures the mated first and second members together by being extended through bores in the mated first and second members.

Abstract: A standardized arched jamb assembly includes an arched jamb member and a pair of opposite upright jamb members with angled cuts made at opposite ends of the arched jamb member and upper end portions of the upright jamb members where the arched jamb member meets and interfaces with the upright jamb members to form the arched jamb assembly. The angled cuts are two-sided and have substantially the same standard angular configurations, irrespective of variations in the radii of curvature of upper arched jamb members used with upright jamb members to provide wall openings of different widths. The two-sided angled cuts are preferably standard right-angled notches and end cuts.

Abstract: A support structure and method for forming same for use in excavations such as underpasses, tunnels and the like for roads, rail or rivers. The support structure allows the utilization of the strength provided by using arch shaped sections and also minimizes the disruption caused to the soil surrounding the excavation thereby allowing existing road, rail or river services to continue to be used during excavation.

Abstract: A joint for pre-cast concrete twin-leaf arch sections is self-aligning when the two arch sections are initially brought into abutting contact with each other. The joint provides a rigid connection between the twin units and is achieved on site by means of re-inforced cast-in-place concrete. Reinforcement splices for the connection are lap splices, and the joint allows pouring the cast-in-place concrete without the need of formwork. For load distributing purposes, a continuous connection of individual arch rings in the longitudinal direction at the arch crown is possible. An initial abutting contact between the twin units is provided by the joint of the present invention. The contact provided by the joint of the present invention is self-aligning, locking, allows the controlled transmission of the abutting force and allows for a temporary connection. The joint includes mechanical elements for aligning and locking the two arch sections together.

Abstract: A method and structure for forming a small building includes a continuous curved wall forming a semi-arcuate arch, the wall comprised of lightweight cellular material such as foamed blocks. The blocks may be identical and interchangeably secured in place by adhesive to form the wall, so that the arch is easily constructed. The arched wall comprises both the longitudinal sides and the top of the structure. In addition, the structure includes an outer skin which covers the entire exterior of the arched wall. The outer skin is both a weatherproof layer and a tension member to apply a compressive force uniformly to the outer surface of the arched wall and significantly augment the load strength of the arch, resulting in a structure that is made very strong with a minimum mass of material.

Abstract: A bunker construction is comprised of precast arch elements which form a semicircular roof of the bunker by engaging cast-in-place footings. A front and back plate cover the front and back of the enclosure defined by the arch elements. A crown element along the apex of the arch and footing blocks at the bottom sides of the arch along the footing facilitate a lightning protection system. Precast concrete panels form lateral sides of the front of the bunker construction and compacted earth coacts with steel stabilizing elements associated with the precast panels and the front plate of the bunker. The entire bunker exterior is covered with compacted earth thereby forming a bunker construction with enhanced structural integrity due to the mechanically stabilized earth in combination with the precast arch elements and front panel members.

Abstract: A civil engineering structure having an arched wall including a plurality of curve shaped elements. Each element bears against one or more other similar elements and has a recess arranged in an outer face for casting a concrete assembly capping piece and reinforcements. Each element also includes at least one rigid bearing piece fastened to the element and has, at a free end of the rigid bearing piece, a surface with a non-planar profile. The rigid bearing piece comes to bear against a similar piece of another element located opposite it. The two rigid bearing pieces have complementary profiles making it possible for them to be wedged vertically.

Abstract: A construction panel is formed of a plurality of elongate subpanels where each subpanel comprises a plurality of expanded polystyrene blocks placed end to end. Tensioning cables pass over the inner and outer surfaces of the subpanels between tensioning plates positioned at each end of the subpanels. Tensioning the cables imparts longitudinal compression in the subpanels, such that the blocks of the subpanels act monolithically. The inner and outer surfaces of the subpanels are longitudinally convex. The panel may be corrugated. The subpanels may be interlocking to form the construction panel.

Abstract: The method of combining barbed wire and conventional bags to create structures includes the steps of: providing a plurality of bags; filling the bags with a predetermined mixture of organic, manufactured, recycled, particulate, fill material; stacking and arranging the bags in a predetermined array; and, placing at least one strand of barbed wire or similar wire between at least a major portion of the stacked layers of bags as they are being stacked to create frictional resistance to sliding between layers and tensile strength in a wall or other structure formed by the stacked layers of bags thereby to provide earthquake resistant structures. The structures include a building structure retaining wall, and an erosion resistant embankment for a body of water made by the method. The bags can be of different length, the fill material can include a cementious material thereby to create a permanent structure and one to three spaced apart strands of barbed wire can be used between layers of bags.

Abstract: A translucent construction block assembly, e.g. for a window or wall panel of non-standard size and/or shape, has a frame extending around an array of hollow translucent construction blocks assembled in horizontal and vertical juxtaposition, the blocks each having front and rear walls connected by a peripheral wall and the array having a periphery engaged by the frame so that the blocks are thereby retained in position. The blocks include partial blocks having openings interrupting the peripheral walls thereof, the partial blocks being juxtaposed with the openings at the periphery of the array. A seal of resilient material interposed between the array and the frame extends between the front and rear walls and closes the openings.

Abstract: An adjustable arch support for use in brick and other masonry construction provides temporary support of a brick or masonry arch during construction. The support provides for adjustment for both width and height, for use in masonry openings of various sizes and shades. A header includes plural fingers extending vertically upward therefrom, with the fingers also being vertically adjustable. Each of the fingers includes a brick or masonry support pivotally attached to the upper end thereof, providing for angular adjustment to properly support a brick or masonry monolith during construction of the arch. The support is adjusted horizontally and vertically to fit the lower rectangular portion of the arch opening, and the fingers are adjusted vertically to form the proper arch shape. One or several more masonry courses may then be constructed, using the arch support for support until the mortar or cement has cured.

Abstract: The composite structures are composed of wooden members such as girders of laminated wooden boards and members of reinforced concrete such as a plate of reinforced concrete which form for instance a composite load supporting structure designed as pedestrian walkway or similar structure. In order to interconnect the members of wood themselves or to members made of reinforced concrete fitted set bolts or fitted screw bolts, respectively, are arranged in such a manner that they extend through the cross sections of the wooden members and are anchored at least in one cross section of reinforced concrete. The parts consisting of reinforced concrete are poured as a rule after the assembling of the wooden structure such that deviations of dimensions can be equalized or taken up, respectively, quite easily. This allows a combining of the advantages of wooden structures and of structures made of reinforced concrete.

Abstract: An underground tubular structural system capable of having a very large cross section, for the construction of urban or rural conduits, underground passages and other civil engineering installations. At least two conduits (S1) (S2), namely, a high conduit (S2) and a low conduit (S1), are superposed and at least the high conduit (S2) is formed in cross section by at least two prefabricated elements, namely a lower element (4) (6) in the shape of an inverted U capping the low conduit (S1) and bearing along two lateral sides (14) of the latter and an upper covering element (2') (5) capping the lower element (4) (6) of the high conduit and closing the section (S2) towards the top. One or more supplementary conduits can easily be added to an already existing conduit.

Abstract: An underground tubular structural system capable of having a very large cross section, for the construction of urban or rural conduits, underground passages and other civil engineering installations. At least two conduits (S1) (S2), namely a high conduit (S2) and a low conduit (S1), are superposed and at least the high conduit is formed in cross section by at least two prefabricated elements, namely a lower element (4) (6) in the shape of an inverted U capping the low conduit (S1) and bearing along two lateral sides (14) of the latter and an upper covering element (2') (5) capping the lower element (4) (6) of the high conduit and closing the section (S2) towards the top. One or more supplementary conduits can easily be added to an already existing conduit.

Abstract: The invention relates to a keystone set for installation in the transition region between two sections of an arch-shaped support structure, the set consisting of two transition stones, between which at least one keystone is axially insertable.

Abstract: An easily transported and erected building structure formed in part as a vault made of interlocking voussoirs in the form of identical insulated boxes. Permanent exterior joint connectors prestress the voussoirs for strength. Easily installed interior clips join the voussiers. A floor made of insulated boxes is supported on a quickly-assembled adjustable structural frame. End walls made of insulating boxes close the ends of the vault or vaults. External cladding and interior finishing panels, corresponding generally to the dimensions of the voussoirs, are easily installed and removed. Interior raceways are formed along the joinder lines of the insulated boxes. All of the parts of the structure are designed for erection of the structure in harsh environments, without handling small loose parts.

Abstract: A pattern for defining the profile of an arch is produced from a unitary block of material or materials having the required structural strength to support the arch materials during construction and sufficient ductility or resilience at its surface to accommodate irregularities present in the arch materials. The pattern may be produced from a single block of polystyrene material whose upper profile corresponds to the desired underside of an arch to be constructed using the pattern and whose undersurface is generally flat.

Abstract: The vaulted building structure comprises a shell (1) made of a composite construction material and formed of arcuate elements (4) of a uniform width having their ends (5) mounted on a base (3). The shell (1) is shaped as a cylindrical vault of which the vertical axis of symmetry includes a vault ridge (2). The ends (5) of the arcuate elements (4) are hingedly braced to the base (3) for rotation about a horizontal axis parallel with the vertical plane of symmetry. The convex outer surface of each arcuate element (4) has its curvature gradually diminishing lengthwise of the arcuate element (4) towards its ends (5) and ridge (2) for levelling out strains generated in the shell (1) upon rotation of the ends (5) of the arcuate elements (4).

Abstract: A method and apparatus for assembling modular tooled masonry structures, the method coprising the steps of: providing a pre-fabricated wire support structure having a shape generally corresponding to the shape of the completed masonry structure; assembling a first row of bricks in a predetermined pattern onto the support structure using the support structure as a support and spacing guide for the bricks; masking selected areas of the bricks by partially surrounding the bricks with an open top removably mortar molding form; applying a pre-determined quantity of mortar into the mortar molding form covering accessible unmasked areas of the bricks with a pre-determined thickness of mortar; leveling the mortar; allowing the mortar to partially set; removing the mortar molding form from the bricks thereby revealing a tooled row of bricks; and repeating the above steps to provide additional tooled rows of bricks as needed to complete the masonry structure.

Abstract: A method of making a domed building structure includes locating a ring beam having a radially inwardly extending circumferential locating formation on top of an upwardly extending building structure. The method also includes locating a plurality of prefabricated dome units adjacent one another on the locating formation of the ring beam, in a first annular course. Further annular courses are then located in position, thereby to form a domed top.

Abstract: A molded roof section for use with dwelling units includes a domed main body portion which is arranged with a leading edge, an opposite trailing edge, and two side edges. The leading edge is configured with strengthening ribs and a defined groove while the trailing edge also including strengthening ribs is configured with a tongue such that the leading edge of one roof section may be assembled to the trailing edge of the contiguous roof section by a tongue-in-groove assembly concept. The side edges of said roof section are arranged with downwardly opening channels which are spaced so as to correspond to the spacing between dwelling unit sidewalls. Each roof section is molded of a high-density polymer foam as a homogeneous, unitary member and each roof section may be easily and readily lifted in place and lowered onto the sidewalls such the sidewalls fit into the downwardly opening channels of each section.

Abstract: A molded roof section for use with dwelling units includes a domed main body portion which is arranged with a leading edge, an opposite trailing edge, and two side edges. The leading edge is configured with strengthening ribs and a defined groove while the trailing edge also including strengthening ribs is configured with a tongue such that the leading edge of one roof section may be assembled to the trailing edge of the contiguous roof section by a tongue-in-groove assembly concept. The side edges of said roof section are arranged with downwardly opening channels which are spaced so as to correspond to the spacing between dwelling unit sidewalls. Each roof section is molded of a high-density polymer foam as a homogeneous, unitary member and each roof section may be easily and readily lifted in place and lowered onto the sidewalls such the sidewalls fit into the downwardly opening channels of each section.

Abstract: A burst panel assembly for normally covering a vent opening of structure which defines an area to be protected from the buildup of dangerously high internal pressures has two frangible panels disposed in spaced, face-to-face relationship along with a core of expanded polyurethane foam which functions to dampen vibrations received from the structure and transmitted to the frangible panels. The foam is introduced in an initially flowable condition into the space between the panels and thereafter expands while curing to a solidified configuration for continuously exerting pressure on both of the panels, to thereby substantially reduce the fatigue stress that would otherwise occur along lines of weakness of burst patterns that are formed in both of the panels.

Abstract: Arch elements (S) of an overfilled load support structure (L) suitable for use in highway construction are associated with a foundation (F) by a hinge (10). The hinge is formed by edges (12,14) of the arch element bearing on a horizontally disposed load bearing surface (22) and a vertically disposed load bearing surface (24). Essentially unrestrained rotation about the edge bearing on the horizontally disposed surface is permitted, and translation of the element is primarily restrained by the edge bearing against the vertically disposed load bearing surface. The rest of the element is spaced from the foundation.

Abstract: A method of assembly adapted for use with underground structures having an arcuate, elongated configuration and constructed of substantially identical blocks joined together with substantially identical fastening means and extending from both sides of a center keystone thereby allowing energy efficient, reliable, low cost structures capable of being mass produced with minimal die or pattern expense.

Abstract: The front wall of an overfilled reinforced concrete arch is built from two prefabricated reinforced concrete elements, that are connected in the center by an on-site cast joint, which transmit the vertical loads acting upon them only to the foundation of the underpass, while the horizontal loads, brought about by the earth pressure from the overfill, are transmitted only at the outer edges to the wing wall and to the arch foundation, on one hand, and on the other hand to the arch from the apex portion. In the apex portion, these forces are transmitted from the front wall to the arch by means of metal rods, that transmit only horizontal stresses.

Abstract: An arch is formed of prefabricated reinforced concrete shells connected at the arch apex by an on-site cast concrete joint is built as a skewed underpass structure. In order to avoid complicated edge elements or a costly lengthening of the underpass, the individual reinforced concrete shells are formed to have their horizontal projection (in the horizontal projection of an assembled underpass) define a parallelogram which includes at least one acute angle which correspond to the acute angle formed by the intersection of the axis of the overpass traffic route with the axis of the underpass traffic route. Thus, edge elements are not necessary. An apex joint is formed of on-site cast concrete. Reinforcement rods extend into the apex joint and are arranged in an asymmetrical manner so that all elements can be designed and reinforced in the same manner with the reinforcement rods in the joint meeting directly.

Abstract: A refractory brick without a metal casing and having built-in expansion at the hot face is formed by having at least one side face divided into two sections, the section adjacent the cold face being of normal configuration, but the section adjacent the hot face being inclined at a greater angle to the opposed side face, whereby expansion allowance is provided at the hot face, the section adjacent the hot face also having at least one raised portion, preferably adjacent the hot face, the height of the raised portion being such that its surface lies substantially in the plane extended of the lower, cold face section. By this construction, a brick is provided with built-in expansion allowance at the hot face, substantial bearing surface at the cold face to prevent loosening of the refractory structure in use, and means to prevent inadvertent closing of the hot face thermal expansion allowance during placement of the brick in a kiln or furnace.

Abstract: A composite arch structure and method of making it are taught. The composite arch structure comprises a pair of retaining wall portions and a top arch portion extending therebetween. A stiffening and load distributing member is structurally affixed to the top arch portion and extends longitudinally of the composite arch structure for the majority of the length of the structure. The composite arch structure preferably also includes longitudinally extending, load spreading buttress means on either side of the vertical axis of the structure at positions where a radial force acting on the structure forms an angle of about 45.degree. or more to the horizontal.

Abstract: An arch block building system to simplify the building of arches in architectural construction and in toy block sets is provided by this invention. The arch block building system, which consists of only four basic shapes, simplifies the builder's construction of arches for use in bridges, entranceways and other structures, and provides an educational tool to teach the principles of arch construction through its use in toy block sets.

Abstract: A concrete segment for a tunnel lining, having an end connectable to an end of another identical segment abutting thereagainst by means of connecting dowels insertable from an end of the segment remote from the abutting end thereof or from one side of the segment into two channels within the segments, each channel extending through an end of the segment and into the end of said abutting segment, the channels being disposed at an angle to one another whereby the segments are held together when the dowels are in position.

Abstract: A novel vault for industrial furnaces, such as glass-making and metallurgical furnaces, comprised of a plurality of arches arranged side-by-side and each composed of a plurality of archstones made of fused cast refractory material. The archstones include a relatively thin slab-like lower portion and at least one upper rib integral therewith extending along the longitudinal direction of the individual arches. The corresponding ribs of the archstones of a given arch are aligned and define recessed portions filled with a refractory concrete having preferably good thermally insulating properties. A highly efficient thermally insulating structure covers the filled archstones.