DOCUMENT NAME: Specification TITLE OF DEVICE: Foundation Structure and Foundation Construction Method TECHNICAL FIELD The present device relates to a foundation structure for a building, and to a construction method therefor. More specifically, the present device relates to a structure for a strip footing (continuous footing foundation) comprising reinforced concrete, and to a construction method therefor. BACKGROUND ART Widely employed as a foundation structure in residential buildings and other buildings of small or moderate size is a strip footing having an inverted T-shaped cross section at which a footing beam is installed over a footing slab. During construction of such a strip footing, a form for formation of the footing slab and a form for formation of the footing beam are installed above the ground surface, and concrete is poured into these forms. With regard to pouring of concrete, techniques in which pouring of concrete for the footing slab and pouring of concrete for the footing beam are carried out in two separate operations, and techniques in which the concrete is poured in a single operation so that the footing slab and the footing beam are formed in monolithic fashion, are both publicly known. SUMMARY OF DEVICE During construction of a strip footing as described above, it is essential that the respective forms for the footing beam and the footing slab be installed in accurate fashion above the ground surface. However, there are many locations at which the ground surface, formed by compaction of gravel, rubble, and so forth, will be uneven, and it will not be easy to install the two types of forms in such fashion that they are accurately positioned over such a ground surface. Moreover, because a large pressure acts on a form when concrete is poured thereinto, it is necessary to tightly retain the entire form so as to prevent that pressure from causing the form to rise or undergo deformation. Furthermore, where concrete is poured in a single 1 5797604_1 (GHMatters) P85821.AU DENISET operation so that the footing slab and the footing beam are formed in monolithic fashion, consideration must be given to making the shape at the interior of the entire form as simple as possible so as to permit concrete to fill the interior of the form without formation of voids. The present device was conceived in light of situations such as the foregoing, and may provide a strip footing structure permitting accurate installation of form(s) without regard to the state of the ground surface, permitting form(s) to be securely retained so as not to undergo deformation even when acted upon by pressure during pouring of concrete, permitting concrete to satisfactorily spread and fill even when concrete is poured in monolithic fashion, and in embodiments permits construction operations to be carried out in efficient and affordable fashion; as well as a construction method therefor. MEANS FOR SOLVING PROBLEM In a first aspect, the invention provides, a foundation structure for a building, the foundation structure made of reinforced concrete and comprising one or more footing slabs and one or more footing beams extending continuously and in parallel fashion with respect to a long direction of a building wall, the foundation structure comprising at least one of the footing beam or beams has rectangular cross-sectional shape, being taller than it is wide, and has encased therewithin at least one pair of main reinforcements, one being an upper reinforcement and the other being a lower reinforcement, extending in the centerline direction thereof, and at least one stirrup that catches onto and is held in place by those upper and lower main reinforcements; at least one of the footing slab or slabs has approximately quarter-circle fan-shaped cross-sectional shape which is convex as viewed from above where it emerges to either side at a lower portion of at least one of the footing beam or beams; and at least one surface of at least one of the footing slab or slabs, this surface being convex as viewed from above, is formed by causing at least a portion of at least one footing slab form, having approximately quarter-circle arcuate cross-section, to be left in place and cast into concrete. Because this foundation structure is such that footing slab(s) have approximately quarter-circle fan-shaped cross-sectional shape(s) which is/are convex as viewed from above where they emerge to either side at lower portion(s) of footing beam(s), this makes it possible to obtain an efficient stress distribution for compressive loads. Furthermore, the 2 5797604_1 (GHMatters) P85821.AU DENISET approximately quarter-circle fan-shaped cross-sectional shape is also advantageous from the standpoint that it allows concrete to satisfactorily spread and fill when concrete is poured in monolithic fashion. In addition, as a result of the fact that surface(s) of the footing slab(s), such surface(s) being convex as viewed from above, is/are formed through use of footing slab form(s), having approximately quarter-circle arcuate cross-section, which is/are intended to be left in place and cast into the concrete, this permits dramatic improvement in affordability and efficiency of foundation construction operations. The at least two anchor bolts that are arranged in paired fashion at at least one of the footing beam or beams so as to straddle the at least one upper main reinforcement; the at least two anchor bolts are respectively encased within cylindrical sheaths so as to prevent grabbing thereof by concrete; and the at least two anchor bolts are linked together in integral fashion as a result of being respectively fastened by nuts at locations near either end of at least one anchor plate at regions near lower ends of the at least two anchor bolts. Such a foundation structure may make it possible for anchor plate(s), which link anchor bolts at regions near lower ends thereof, to provide the strength to bear large forces that might otherwise cause column feet to be pulled apart from their supports during an earthquake, so that the maximum strength of the foundation can be exploited. In another aspect of the invention, there is provided a foundation construction method, being a method for constructing a foundation made of reinforced concrete and comprising one or more footing slabs and one or more footing beams extending continuously and in parallel fashion with respect to a long direction of a building wall, is characterized in that at least one pair of main reinforcements, one being an upper reinforcement and the other being a lower reinforcement, are arranged in parallel fashion with respect to a centerline direction of at least one of the footing beam or beams, and at least one stirrup catches onto and is held in place by those upper and lower main reinforcements; at least one footing beam form is formed by arranging, over at least one platform placed on a ground surface, sheathing panels, which are made of steel plates having flat surfaces, in mutually opposed fashion so as to straddle the at least one footing beam centerline direction, and moreover linking at least a portion of the sheathing panels in the at least one footing beam centerline direction; at least one footing slab form is formed by arranging curved panels, each of which is made of lightweight resin and has approximately quarter-circle arcuate cross-section, in mutually 3 5797604_1 (GHMatters) P85821.AU DENISET opposed fashion and so as to be convex as viewed from above, to either side below at least a portion of the at least one footing beam form, and causing at least one top rim of at least a portion of the curved panels to engage with at least one bottom rim of at least a portion of the sheathing panels, and moreover linking at least a portion of the curved panels in the at least one footing beam centerline direction; at least one anchor bolt is provisionally installed at at least one prescribed location within the at least one footing beam form; and the foundation is constructed by pouring concrete in monolithic fashion within at least a portion of the at least one footing slab form and at least a portion of the at least one footing beam form, disassembling at least a portion of the at least one footing beam form after the concrete has cured, and causing at least a portion of the at least one footing slab form to be left in place and cast into the concrete. This construction method can make it possible to efficiently install foundation form(s) above ground surface(s), and can make it possible to reduce inconvenience and conserve labor following pouring of concrete. The at least one anchor bolt is provisionally installed within the at least one footing beam form, the at least one anchor bolt is positioned after causing at least one gauge member to span respective top rims of the mutually opposed sheathing panels. This construction method may make it possible to increase the accuracy with which anchor bolt(s) is/are set in concrete. Moreover, in an embodiment, a foundation construction method further comprises, when at least one steel column is installed atop the foundation after the concrete has cured, the at least one anchor bolt, which protrudes from at least one top of at least one of the footing beam or beams, is inserted in at least one base plate, which is provided at at least one bottom of the at least one steel column; a height and plumb of the at least one steel column are adjusted; at least one nut is tightened to its final torque on the at least one anchor bolt; and at least one gap between the at least one base plate and the at least one top of at least one of the footing beam or beams is thereafter filled with an epoxy-type resin grout. The epoxy-type resin grout employed in this construction method may have good flow characteristics, allowing it to penetrate small gaps between base plate(s) and top(s) of footing beam(s) before curing takes place. This construction method may make it possible to install steel column(s) over foundation(s) in rapid, hassle-free, and accurate fashion. 4 5797604_1 (GHMatters) P85821.AU DENISET Foundation(s) attained through employment of building foundation structure(s) in accordance with an embodiment of the present device may provide excellent earthquake resistant characteristics and are favorably suited to monolithic pouring of concrete. Furthermore, foundation construction methods in accordance with an embodiment of the present device may make it possible to efficiently and affordably construct form(s) for formation of the aforementioned foundation(s). BRIEF DESCRIPTION OF DRAWINGS Embodiments will now be described with reference to the accompanying non-limiting drawings, in which: FIG. 1 Perspective view of vertical section of a foundation associated with an embodiment of the present device. FIG. 2 Perspective view showing structure of forms for a foundation associated with an embodiment of the present device. FIG. 3 Vertical sectional view showing structure of forms for a foundation associated with an embodiment of the present device. FIG. 4 Perspective view showing an embodiment of a support fixture for a footing slab form. FIG. 5 Vertical sectional view showing how the support fixture of FIG. 4 is installed within foundation forms. FIG. 6 Perspective view showing another embodiment of a support fixture for a footing slab form. FIG. 7 Vertical sectional view showing how the support fixture of FIG. 6 is installed within foundation forms. FIG. 8 Perspective view showing an embodiment of a gauge member. FIG. 9 Partial enlarged sectional view showing an exemplary constitution of nuts used at the gauge member of FIG. 8. FIG. 10 Top view showing an embodiment of a gauge member that may be used at a corner location in a foundation. 5 5797604_1 (GHMatters) P85821.AU DENISET FIG. 11 Top view showing an embodiment of a gauge member that may be used at an intersecting location in a foundation. FIG. 12 Perspective view showing an example of a gauge member that may be used at a location where a top of a foundation is to be lower than a top rim of a sheathing panel. FIG. 13 Exploded perspective view showing another example of a gauge member that may be used at a location where a top of a foundation is to be lower than a top rim of a sheathing panel. FIG. 14 Exploded perspective view showing yet another example of a gauge member that may be used at a location where a top of a foundation is to be lower than a top rim of a sheathing panel. FIG. 15 Perspective view showing exemplary structure of forms at a location where a step is produced at the top rims of a footing slab form. FIG. 16 Perspective view showing a construction procedure that may be employed when installing a steel column atop a footing beam. FIG. 17 Vertical sectional view showing a location at which a steel column is installed atop a footing beam. EMBODIMENTS FOR CARRYING OUT DEVICE Below, embodiments of the present device are described with reference to the non limiting drawings. BASIC CONSTITUTION OF FOUNDATION FIG. 1 shows cross-sectional structure of a typical portion (rectilinear portion) of a foundation associated with the present device. The foundation comprises footing beam 1, which extends continuously and in parallel fashion with respect to the long direction of the building wall(s); and footing slab 2, which emerges in sideward fashion to either side of the lower portion of footing beam 1. Footing beam 1 is such that the cross-sectional shape thereof is rectangular, being taller than it is wide; furthermore, at least one pair of upper and lower main reinforcements 11, 12 are arranged centrally in the width direction thereof. Stirrups 13, each of which has 6 5797604_1 (GHMatters) P85821.AU DENISET hook-like upper and lower portions, catch onto and are held in place at appropriate intervals by upper and lower main reinforcements 11, 12. Footing slab 2 is formed such that the portions emerging to either side at the lower portion of footing beam 1 have approximately quarter-circle fan-shaped cross-sectional shapes which are convex as viewed from above. The overall width at the base of the footing slab 2 is approximately 3 to 4 times the width of footing beam 1. Characteristics of concrete being such that application of a large compressive load thereto will produce a fracture line at 450 to the direction in which the compressive load is applied, employment of such fan-shaped cross-sectional shape at footing slab 2 makes it possible to provide adequate compressive strength substantially only at portions below where such fracture line would be produced. Adoption of such efficient cross-sectional shape makes it possible to reduce the scale of, or even eliminate, reinforcing mat(s) or the like (not shown) that are arranged, or that would otherwise need to be arranged, in parallel fashion with respect to the base of footing slab 2. Anchor bolts 3, for linking to the upper structure of the building, are set into footing beam 1. In an exemplary embodiment, in order to link base plate 41, which is welded to the lower end of steel column 4, to footing beam 1, four anchor bolts 3 are arranged in a configuration that appears rectangular as viewed from above at each such location where a steel column 4 is to be linked thereto. These anchor bolts 3 are arranged in pairs of two bolts that face each other from opposite sides in the width direction of footing beam 1, such that main reinforcement 11 disposed thereabove is straddled therebetween. As shown in partial cutaway fashion at FIG. 1, each anchor bolt 3 is encased within a thin-walled cylindrical sheath 31 comprising, e.g., soft synthetic resin or the like so as to prevent grabbing thereof by concrete. Sheaths 31 are such that regions near the lower ends of respective anchor bolts 3 are exposed, anchor plate 32 being attached to such regions near the lower ends thereof. Bolt through-holes are formed at two locations near either end of anchor plate 32, two anchor bolts 3 being linked together in integral fashion anchor bolts 3 are respectively fastened by nuts 33 to those bolt through-holes. By thus achieving a state such that concrete does not grab the surfaces of anchor bolts 3 which are set into the foundation, even in the event of an earthquake when large forces that would tend to pull apart members act at columns, anchor bolts 3 can undergo elastoplastic deformation in stable fashion without causing damage to surfaces thereof that come in 7 5797604_1 (GHMatters) P85821.AU DENISET contact with concrete, and because anchor plate 32 is made to provide adequate bearing strength, the maximum strength of the foundation can be exploited. FORMS FOR POURING FOUNDATION The foundation constituted as described above may be formed in a single operation by pouring concrete into the space within a form comprising combination of footing beam form 10 and footing slab form 20. Below, the constitution and sequence of operations for construction of respective forms 10, 20 are described with reference to FIGS. 2 and 3, which show the structure of forms for a foundation associated with the present device. Footing beam form 10 is formed by arranging sheathing panels 100, which are made of steel plates having flat surfaces, in symmetric fashion so as to straddle the centerline of the foundation. Provided at the back rim of sheathing panel 100 are top rim rib 101 and bottom rim rib 102, which have lip-like profile; and left and right side ribs 103, which have box shaped cross-section. Furthermore, the inner portion at the back of sheathing panel 100 is provided with vertical and horizontal reinforcing ribs 104, 105 comprising slat-like members. The sheathing panel(s) 100 rest on platforms 14 placed at appropriate intervals on ground surface 91. Moreover, respective sheathing panels 100 are supported so as to prevent movement thereof by means of appropriate support timbering (not shown) installed to the outside of sheathing panels 100. Sheathing panels 100 adjacent in the foundation centerline direction are linked together using roughly U-shaped clamping fasteners 107 to clamp together the respective side ribs 103 thereof, or by means of some other suitable method. Footing slab form 20 is formed by arranging curved thin rectangular panels 200, which may, for example, comprise polystyrene or other such lightweight resin, in symmetric fashion so as to straddle footing beam form 10. Curved panel 200 is curved so as to have approximately quarter-circle arcuate cross-section in the width direction, i.e., in a plane perpendicular to the foundation (or footing beam) centerline, a plurality of reinforcing ribs 201 being formed in the circumferential direction at the curved surface portion thereof. Extending from the bottom rim running in the long direction of curved panel 200 is planar bottom rim landing flange 202, and extending from the top rim of same is top rim engagement flange 203 having L-shaped cross-section. 8 5797604_1 (GHMatters) P85821.AU DENISET This curved panel 200 is installed to the outside of footing beam form 10 so as to be convex as viewed from above. At this time, bottom rim landing flange 202 of curved panel 200 is made to rest directly on ground surface 91, and is secured to ground surface 91 as necessary by driving stakes (not shown) thereinto or through use of other such suitable means. Furthermore, top rim engagement flange 203 of curved panel 200 is made to engage from above with bottom rim rib 102 of sheathing panel 100 making up footing beam form 10. In addition, appropriate clamping fixtures (not shown) are made to mate with bottom rim rib 102 of sheathing panel 100 and top rim engagement flange 203 of curved panel 200, or other such suitable means is employed, to link curved panel 200 and sheathing panel 100. Cutout slot(s) 204 or the like, for insertion of side rib(s) 103 and/or vertical reinforcing rib(s) 104 of sheathing panel 100, may be formed in the top rim engagement flange of curved panel 200. Curved panels 200 adjacent in the foundation centerline direction are linked together by causing the respective side edges thereof to mutually overlap by an appropriate width, or by means of some other suitable method. Note that at corners where the foundation makes a turn in L-shaped fashion as viewed from above, at intersections where foundation segments are connected in T-shaped fashion as viewed from above, and/or at other such locations, footing beam form 10 and footing slab form 20 are assembled such that appropriate accessory panel(s) fabricated to accommodate the shape of the region in question are installed so as to intervene in continuous fashion between standard regions. When the foundation forms are assembled in this fashion, the region to the outside of footing slab form 20 is backfilled by soil 92. Pressure from this soil holds footing slab form 20 in place so that it does not move. With these in this state, concrete is poured into the form. Because footing beam form 10 is open at the lower portion thereof, concrete poured thereinto from above flows into the interior of footing slab form 20 to reach corner regions thereof without difficulty. When the concrete has hardened after passage of a prescribed cure time, footing beam form 10 is disassembled. Platforms 14 and footing slab form 20 are left in place, being cast into the concrete. 9 5797604_1 (GHMatters) P85821.AU DENISET FOOTING SLAB FORM SUPPORT FIXTURES Footing slab form 20 comprising lightweight resin has a tendency to easily undergo deformation as a result of being influenced by pressure from backfilled soil and/or poured concrete, or as a result of being influenced by unevenness at ground surface 91. Support fixtures are therefore employed as necessary to accurately maintain the shape of footing slab form 20. Two exemplary constitutions for such support fixtures are given below. Support fixture 21 shown in FIGS. 4 and 5 is a member whose primary skeleton is a planar triangular truss wherein two more or less congruent triangles formed from wire are coupled in tandem fashion above their collinear mutual bases 211. At either end of the base of that planar triangular truss, linear portion 212 extending outwardly from base 211, and linear portion 214 extending outwardly from outer oblique side 213 of the triangular truss so as to be bent in parallel fashion with respect to base 211, are mutually separated by a certain distance in the foundation centerline direction, being joined by way of inverted U-shaped raised portion 215. The distance between the two raised portions 215 corresponds to the width dimension of footing slab 2. Furthermore, upwardly directed erect portions 216 extend from the vertices of the two triangles of the planar triangular truss, mutually facing bent portions 217 being formed at the upper ends of said erect portions 216. The distance between the two erect portions 216 corresponds to the distance between the outside faces of footing beam form 10, and the height measured from bases 211 of the triangular truss to bent portions 217 thereof corresponds to the height at which footing slab form 20 is installed. After footing beam form 10 has been installed above platforms 14, these support fixtures 21 are arranged at appropriate intervals between platforms 14. The two bent portions 217 of each support fixture 21 are made to engage with bottom rim ribs 102 of footing beam form 10 from the respective outsides thereof In addition, top rim engagement flanges 203 of footing slab form 20 are placed over and are made to engage with the two bent portions 217 of this support fixture 21. At the same time, bottom rim landing flanges 202 of footing slab form 20 are placed over linear portions 212, 214 at either end of this support fixture 21, being straddled between the two raised portions 215 so as to be constrained from moving in the width direction, i.e., in a plane perpendicular to the foundation (or footing beam) centerline. Footing slab form 20 is thus appropriately positioned without being influenced by unevenness 10 5797604_1 (GHMatters) P85821.AU DENISET at ground surface 91, and is securely retained in such fashion that it is not easily moved or deformed even when acted upon by pressure from soil 92 and/or concrete. Support fixture 22 shown by way of example in FIGS. 6 and 7 is constituted by combination of spreader member 221 comprising thin steel plate or the like, and bent support member 225 comprising wire formed into the shape of a closed curve. Spreader member 221 is such that upwardly bent portions 222, which are bent so as to be directed upward, are provided at either end of a slender rectangular steel plate. At locations further upward from these upwardly bent portions 222, necked portions 223 are formed in such fashion as to permit bending by fingertip pressure. The distance between the two upwardly bent portions 222 corresponds to the distance between the outside faces of footing beam form 10. Furthermore, at two locations toward the middle of the steel plate, the steel plate is pierced and bent upward to form tabs 224. The distance between these tabs 224 corresponds to the distance between the inside faces of footing beam form 10. Bent support member 225 is provided with two linear portions 226, 227, one being long and the other being short, which are arranged in parallel fashion such that the gap therebetween is smaller than the width dimension of spreader member 221; oblique portions 228, which are linear in shape, being bent so as to extend diagonally downward from either end of short linear portion 227; and arched portions 229, which curve diagonally downward as they extend from either end of long linear portion 226. In addition, the two linear portions 226, 227 are linked to the bottom of spreader member 221 by welding or other suitable attachment means. The curved shape of arched portion 229 is formed so as to conform to the concavity of reinforcing ribs 201 of footing slab form 20. After footing beam form 10 has been installed above platforms 14, these support fixtures 22 are arranged at appropriate intervals between platforms 14. In addition, spreader member 221 is installed from below footing beam form 10, bottom rim rib 102 at either side of footing beam form 10 being sandwiched between an upwardly bent portion 222 and a tab 224. With the assembly in this state, by bending necked portions 223 inward it is possible to cause spreader member 221 to become attached to footing beam form 10. Moreover, top rim engagement flanges 203 of footing slab form 20 are placed over and are made to engage with these necked portions 223. The curved surface portions of footing slab form 20 are supported from the inside by arched portions 229 of bent support 11 5797604_1 (GHMatters) P85821.AU DENISET member 225. Footing slab form 20 is thus appropriately positioned without being influenced by unevenness at ground surface 91, and is securely retained in such fashion that it is not easily moved or deformed even when acted upon by pressure from soil 92 and/or concrete. The aforementioned two varieties of support fixtures 21, 22 are left in place, being cast into the concrete. However, as the structures of both support fixtures 21, 22 are extremely simple, the cost incurred in doing so will be small. GAUGE MEMBER FOR POSITIONING ANCHOR BOLTS Columns and so forth in the main portion of the building are linked to the foundation by way of anchor bolts 3. Anchor bolts 3 set into footing beam 1 must be accurately positioned therewithin in accordance with the dimensions dictated by the design of the main portion of the building. Gauge member(s) for retaining anchor bolt(s) 3 is/are therefore employed so as to permit accurate positioning of anchor bolts(s) 3 within footing beam form 10 and so as to prevent anchor bolt(s) 3 from being moved or tilted due to pressure from poured concrete. The basic constitution of the gauge member is such that it comprises steel plate or other such plate of such size as to be capable of spanning the distance between the tops of mutually opposed sheathing panels 100 of footing beam form 10; it is provided at the side edges of the plate with means for fastening to top rim ribs 101 of sheathing panels 100 or other such portion thereof, and it is provided at the central portion of the plate with means for retaining anchor bolt(s) 3. Specific exemplary constitutions of gauge members are given below. Gauge member 51 shown in FIG. 8 comprises an elongated rectangular plate, a plurality of attachment holes 511 being formed along the long side edges thereof This gauge member 51 is placed on top rim ribs 101 of sheathing panels 100 such that attachment holes 511 are made to overlap insertion holes formed in top rim ribs 101, and when bolts 512, pins, or the like are inserted thereinto, this causes gauge member 51 to be fastened to footing beam form 10. At such time, as shown in the drawing, adjacent gauge members 51 may be placed such that their respective ends are made to partially mutually overlap. At the short and long sides of gauge member 51, guides 513, 514 for aligning gauge member 51 to the foundation centerline and/or to column axis or axes are notched thereinto in V-shaped fashion. 12 5797604_1 (GHMatters) P85821.AU DENISET Furthermore, more or less rectangular opening 515 is formed at the inner portion of gauge member 51, concrete being poured into the form via this opening 515. Anchor bolts 3 are inserted into bolt support holes 516 formed in the bridge-shaped portions that bound opening 515, nuts 517, 518 being tightened against gauge member 51 from above and below to fasten these thereto. Bolt support holes 516 are formed at multiple locations so as to accommodate a variety of main building structures. As shown in FIG. 9, nuts 517, 518 may each be such that the bearing surface thereof protrudes to form squat cylindrical stepped portion 519, this stepped portion 519 being inserted into bolt support hole 516 during fastening. Adoption of such a constitution will make it possible to increase the clearance at bolt support hole 516 without reducing the accuracy with which anchor bolt 3 is positioned. This will facilitate removal of gauge member 51 following curing of concrete. Gauge member 52 shown in FIG. 10 is for corner locations where the foundation makes a turn, without break, in L-shaped fashion as viewed from above, the overall plate being formed in L-shaped fashion as viewed from above. Furthermore, gauge member 53 shown in FIG. 11 is for intersecting locations where foundation segments are connected in T shaped fashion as viewed from above, the overall plate being formed in T-shaped fashion as viewed from above. As both gauge members 52, 53 are such that constitution of attachment holes 511, bolt support holes 516, and so forth is similar to that of gauge member 51 shown in FIG. 8, like components have been given like reference numerals and detailed description thereof will be omitted. FIGS. 12 through 14 show constitution in situations where gauge members are employed in specific applications. These gauge members are utilized at locations where step(s) occur at the top of footing beam 1. There are many situations in which strip footings for residences or the like are designed such that the top of a partition wall foundation is lower by on the order of 10 cm than the top of the perimeter foundation. During formwork operations in connection with such foundations, where sheathing panels 100 made of steel plate are employed, it will typically be the case that sheathing panels 100 of identical dimensions are assembled so as to have identical height at both the perimeter foundation and the partition wall foundation. 13 5797604_1 (GHMatters) P85821.AU DENISET At such a partition wall foundation, anchor bolts 3 will need to be retained at locations somewhat lower than the top rims of sheathing panels 100. At such locations, a gauge member 54 such as that shown in FIG. 12 might, for example, be employed. This gauge member 54 is such that side edge portions 541 are capable of spanning the distance between the tops of sheathing panels 100, middle portion 542 is bent so as to drop in stepped fashion to a level lower than the side edge portions, and bolt support holes 516 are formed in this middle portion 542. Furthermore, gauge member 55 shown in FIG. 13 comprises combination of flat span plate 551, which has constitution similar to that of gauge member 51 shown in FIG. 8; auxiliary plate 552, which is attached in layered fashion to the top or bottom face of span plate 551; cylindrical portions 553, which extend in downwardly directed fashion from the bottom face of auxiliary plate 552; and bolt extenders 554, which are inserted within cylindrical portions 553. Auxiliary plate 552 is such that attachment holes 555 are formed at the periphery thereof, bolts 512 and/or pins being used to secure this to span plate 551 and/or top rim ribs 101 of sheathing panels 100. Cylindrical portion 553 has an inside diameter such as will permit bolt extender 554 to be inserted therewithin. The top end of each cylindrical portion 553 is affixed in integral fashion to auxiliary plate 552. Welded to the bottom end of bolt extender 554 is coupling nut 556, which is capable of threadedly engaging with anchor bolt 3. In addition, after threading or otherwise passing the top end of anchor bolt 3 through jam nut 557 and washer 558, the top end of anchor bolt 3 is threadedly engaged with coupling nut 556 of bolt extender 554. This bolt extender 554 is inserted within cylindrical portion 553 and is made to protrude above auxiliary plate 552, and nut 559 is fastened thereonto from above so as to secure these. Gauge member 56 shown in FIG. 14 is similar to gauge member 55 shown in FIG. 13, and comprises combination of flat span plate 561; auxiliary plate 562, which is attached in layered fashion to the bottom face of span plate 561; cylindrical portions 563, which extend in downwardly directed fashion from the bottom face of auxiliary plate 562; and bolt extenders 564, which are inserted within cylindrical portions 563. In addition, the top end of anchor bolt 3 is joined to bolt extender 564, bolt extender 564 is inserted within cylindrical portion 563 and is made to protrude above auxiliary plate 562, and nut 569 is fastened thereonto from above so as to secure these. 14 5797604_1 (GHMatters) P85821.AU DENISET With the assembly in this configuration, auxiliary plate 562 is made to engage with guide rail 565, which is provided at the bottom face of span plate 561, causing it to be retained in such fashion as to permit sliding in the centerline direction. This makes it possible to make fine adjustments to the positions of anchor bolts 3. Cutouts 567 are formed at side edges of span plate 561 so as not to interfere with movement of bolt extenders 564 at locations where these protrude above auxiliary plate 562. After auxiliary plate 562 has been appropriately positioned, screw fasteners 568, which are attached to span plate 561, are tightened to secure this thereto. Employment of gauge member 54, 55, 56, and/or the like such as have been as described above makes it possible to securely retain anchor bolts 3 at locations lower than the top rims of sheathing panels 100. In the context of a strip footing at which the top of a partition wall foundation is to be lower than the top of the perimeter foundation, FIG. 15 shows the structure of a form which is such that use of sets of sheathing panels 100 having respectively different dimensions permits existence of step(s) at top rims of footing beam form 10. At an intersecting location where the perimeter foundation form, the top of which is at a high level, and a partition wall foundation form, the top of which is at a low level, are connected in T-shaped fashion as viewed from above, planar gauge members 51 as shown in FIG. 8 are placed on the tops of respective footing beam forms 10. Those gauge members 51 are linked by way of step linking members 57. Step linking member 57, being a member which is made of steel and which has more or less channel-shaped cross-section, has lower plate 571; erect plate 572; and upper plate 573. Lower plate 571 is secured by way of pin(s) and/or bolt(s) to the top face of the gauge member 51 at the partition wall foundation side, the top of which is at a low level; and upper plate 573 is secured by way of pin(s) and/or bolt(s) to the bottom face of the gauge member 51 at the perimeter foundation side, the top of which is at a high level. By thus assembling sets of sheathing panels 100 having different dimensions in correspondence to the different levels to which the respective tops will be poured, and using step linking members 57 to link gauge members 51, 51 spanning these at locations including where they intersect, it is possible to improve ease of construction operations related to the foundation forms. 15 5797604_1 (GHMatters) P85821.AU DENISET STEEL COLUMN INSTALLATION METHOD A sequence of operations that may be employed when installing steel column 4 atop footing beam 1 formed as described above is described with reference to FIGS. 16 and 17. When pouring concrete, height and level of footing beam 1 are adjusted so as to achieve a top surface thereof that is as smooth as possible. Where necessary, a thin layer of top leveling substance 15 comprising mortar or other such substance having good flow characteristics may be spread over the entire top surface of the concrete. Following curing of concrete, footing beam form 10 is disassembled. Base plate 41 is welded in advance to the bottom of steel column 4, anchor bolt through-holes being formed in base plate 41. Steel column 4 is made to stand atop footing beam 1, and anchor bolts 3 are inserted through the anchor bolt through-holes of base plate 41. Nuts 34 are threaded onto anchor bolts 3 but are not yet fully tightened, at which time the structure thereabove including beam(s) and so forth is provisionally assembled thereover, and after any necessary adjustments are made to the profile (height and plumb) of steel column 4, nuts 34 are tightened to their final desired torque. Because it is difficult to achieve a perfectly smooth surface at the top of footing beam 1, small gap(s) may remain between base plate 41 and the top of footing beam 1 even after the base plate 41 of steel column 4 has been secured to the top of footing beam 1 in this fashion. It is preferred that any such gaps be filled with epoxy-type resin grout 16. Epoxy-type resin grout 16 comprises a resin component and a hardener component, these being mixed together in a prescribed mixture ratio at the construction site before being used. As resin component, any of various epoxies, special-purpose epoxies, or the like may be used. Furthermore, as hardener component, any of various polyamide amines, alicyclic polyamines, modified polyamines, or the like may be used. Such epoxy-type resin grout 16 will have good flow characteristics, allowing it to penetrate small gaps. One practical method for filling such regions with epoxy-type resin grout 16 is to use sealant 17 to occlude any gap(s) between the periphery of base plate 41 and the top of footing beam 1, and inject epoxy-type resin grout 16 thereinto via filler hole(s) 42 formed in advance in base plate 41. In some cases, the region peripheral to base plate 41 might be surrounded by an appropriate dam-like member (not shown), sealant might be used to occlude any gap(s) 16 5797604_1 (GHMatters) P85821.AU DENISET between the dam member and the top of footing beam 1, and epoxy-type resin grout 16 might be injected into the region interior with respect thereto. Furthermore, as shown in FIG. 17, during installation of steel column 4 atop footing beam 1, small spacers 18 comprising sheet stock might be arranged so as to be straddled between base plate 41 and the top of footing beam 1. By so doing, it is possible to enlarge the gap between base plate 41 and the top of footing beam 1, facilitating ability of epoxy-type resin grout 16 to spread itself about therewithin. Furthermore, the thickness(es) of spacer(s) 18 may be utilized to facilitate adjustment of height and plumb during installation of steel column 4. Filling of such regions with epoxy-type resin grout 16 may be carried out at any time after nuts 34 have been tightened to their final torque on anchor bolts 3. Furthermore, because subsequent construction tasks may be carried out without having to wait for epoxy-type resin grout 16 that has been injected therewithin to cure, this also has the advantage of shortening the time required for construction operations. An embodiment of the present device may be favorably employed in residential buildings and other such wooden buildings of small or moderate size as well as in steel-frame buildings. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 17 5797604_1 (GHMatters) P85821.AU DENISET