Patent Abstract:
A building frame resistant to earthquakes, gale-force wind loads, fire, insects and rot includes a peripheral frame wall constructed of rectangular steel tubing. Side wall frame modules bolted together along adjacent edges, and end wall modules bolted together along adjacent edges and to the ends of the connected side wall modules form the peripheral frame wall. Diagonal bracing is built into selected side and end wall modules as required for the desired degree of wind resistance. Trusses made of various size tube such as 2×3 inch rectangular steel tubing for supporting a roof, including a hip roof, on the peripheral wall, are assembled and welded in a welding shop and the prefabricated trusses and wall modules are trucked to the building site. Multiple stories may be erected and fastened together by anchor brackets arranged bottom-to-bottom above and below the second and higher floors. The building frame is secured to a foundation by attaching the anchor brackets to anchor bolts set in the foundation.

Full Description:
This invention relates to improved modular frames for buildings and buildings constructed from such frames, and more particularly to high quality buildings that can be erected quickly and at low cost from tubular steel modular frame units that are fabricated off site and trucked to the building site where they are bolted together into a building frame by a small work crew without the use of heavy equipment. 
     BACKGROUND OF THE INVENTION 
     Conventional building practice for residence housing and small commercial buildings relies primarily on wood frame construction in which the building frame is constructed on site from framing lumber cut to fit piece-by-piece individually. It is a labor intensive process and demands considerable skill from the carpenters to produce a structure that has level floors, perfectly upright walls, square corners and parallel door and window openings. Even when the building frame is constructed with the requisite care and skill, it can become skewed by warping of the lumber, especially modern low grade lumber produced on tree farms with hybrid fast-growth trees. 
     Although conventional wood frame buildings require very little equipment for construction, they have become quite costly to build. The labor component of the cost is substantial, partly because of the wages that must be paid for the laborious process of constructing the frame, and partly because of the many government mandated extra costs such as workman&#39;s compensation and liability insurance, social security payments, medical insurance premiums, and the host of reports that must be made to the Government by employers. Accordingly, employers now seek to minimize their work force by whatever means is available to minimize these burdensome costs. 
     Steel frame construction, usually referred to as “red iron” construction, is commonly used on commercial buildings because of its greater strength, fire resistance and architectural design flexibility. The parts of such a steel frame are typically cut and drilled to order in accordance with the architect&#39;s plans, then trucked to the building site and assembled piece-by-piece with the use of a portable crane. The building can be made precisely and as strong as needed, but the cost is relatively high because of the costly materials and the skilled crew and expensive equipment need to assemble the building. It is a construction technique generally considered unsuitable for single family residence building because the cost is high and the building walls are substantially thicker than those made using standard frame construction, so standard door and window units do not fit properly and must be modified with special trim that rarely produces the desired aesthetic appearance. 
     Earthquake damage is becoming a matter of increasing concern among homeowners because of the publicity given to damage and loss of life in recent earthquakes in the U.S. and abroad. Earthquake preparedness stories and advice abound, but an underlying unresolved concern is that conventional wood frame homes in the past were not built to tolerate the effects of an earthquake, neither in its ultimate load-bearing capability nor its post-quake serviceability limits. Modern building codes attempt to address this concern, but the measures they require merely add to the already high cost of a new home and may not always provide significantly improved resistance to earthquake damage, particularly with respect to after-quake serviceability. 
     Fire often follows an earthquake, as happened in the disastrous Kobe earthquake of 1994, and of course fire is a major threat to homes independent of earthquake. When fire breaks out in a conventional home, the wood frame fuels the fire and reduces the chances of successfully extinguishing it before the entire structure is destroyed. The major life saving advance in the recent past is the fire alarm which detects the fire and alerts the occupants that a fire has started so they may escape before burning up with the house, but significant improvements to the fire resistance of the home itself that would retard the spread of the fire would be desirable. 
     The other major catastrophic threat to homes is wind. Wind loads on wood frame homes have destroyed many homes, primarily because the roof is usually attached so weakly to the walls that the combination of lift, exerted upward on the roof by the Bernoulli effect of the wind flowing over the roof, and pressure under the eves tending to lift the roof off the walls, wrenches the roof off the walls and allows the wind to carry the roof away like a big umbrella. Without the roof, the walls of the house collapse readily under the wind load, completing the total destruction of the house. 
     Termite and carpenter ant damage to wood frame homes is a major form of damage, costing many millions of dollars per year. Although the damage done by insects is rarely life threatening, it is actually more extensive in total than the combined effects of wind and earthquake, and it is an ever-present danger in many parts of the country. 
     Thus, there has existed an increasing need for a home building frame design that would enable the inexpensive construction of homes that are highly tolerant of the effects of earthquakes, do not support combustion, are capable of withstanding high winds, are immune to damage from insects, and can use standard building components such as door and window units. Such a building frame concept would be even more commercially valuable if it were possible to erect the building in a short time with a small crew and without heavy equipment, and the frame could be adapted to produce buildings of attractive building styles desired locally. Such a building frame is disclosed in U.S. Pat. No. 6,003,280 issued to Orie Wells on Dec. 21, 1999 and assigned to the assignee of this application. However, numerous improvements were found to be desirable in the building frame system shown in that patent for improved design flexibility, fabrication economy, ease of assembly and improved structural strength and resistance to adverse environmental conditions. 
     SUMMARY OF THE INVENTION 
     Accordingly, this invention provides an improved building frame, ideally suited for single story and multi-story buildings, that can be assembled rapidly at the building site by bolting together metal frame modules fabricated off site and attaching sheet metal elements that simplify the finishing of the building with exterior sheathing and interior wall board. This invention also provides an improved metal frame for a building having integral internal diamond bracing that enables the building to withstand the racking of severe earthquakes and high winds yet be cost competitive with comparable wood frame buildings. This invention provides an improved process for constructing a building frame that uses low cost standard frame modules for the majority of the frame and shorter or lower versions of the standard modules to adjust the length or height of the frame walls to accommodate any desired building size and joist height for floors between stories, to produce a building frame that is cost competitive with conventional wood frame buildings and substantially more resistant to damage from wind, fire and earthquakes. A further object of this invention is to provide an improved steel frame building having walls the same thickness as conventional wood frame buildings, so that standard door and window units can be used with normal appearance, but the building has the strength of a steel frame building and superior fire resistant benefits, while remaining cost-competitive with conventional wood frame buildings. This invention also provides an improved steel building frame that can be erected quickly in multiple stories using standard frame and anchor brackets. The invention provides a roof frame system using rectangular steel tubing that can accommodate virtually all desired roof designs, including hips and gables. 
     These and other features of the invention are attained in a building frame having side walls made of side wall frame modules bolted together along adjacent edges and end walls made of end wall frame modules bolted together along adjacent edges. The frame modules are constructed of rectangular steel tubing, typically 2″×2″, welded together in a welding jig to ensure exact 90° angles. The gauge or thickness of the tubing walls is selected for the desired strength. The wall frame modules, other than the window and door modules, have diagonal diamond bracing to provide rigidity against folding or wracking wind loads and forces experienced during earthquakes. The end walls are each bolted at their ends to ends of the side walls to form a peripheral wall of the building. Trusses for supporting a roof on the peripheral wall are bolted into pockets on top of the side walls between structural members at the top of the wall to secure the roof of the building on the peripheral wall, and structural tubing elements are connected diagonally to the trusses, coplanar with the top chords of those trusses, for supporting purlins adjacent the ridges of a hip roof. The peripheral wall is secured to a concrete foundation by attachment of the frame modules to special anchor brackets bolted to anchors set in a concrete foundation. The same anchor brackets can be arranged in pairs, oriented bottom-to-bottom, clamping between them the second story floor panels, to secure the frame wall of the second and subsequent stories to the supporting story below it and to establish high strength tensile load path between the foundation and the frame modules and the roof trusses. Light gauge metal elements are fastened on the inside and outside surfaces of the wall frame modules for speedy attachment of interior wall board and exterior siding. The roof is supported by longitudinally extending purlins that are attached to the trusses by the use of U-shaped brackets that are pre-welded to the top of the trusses. A canted eve strut is supported atop the side and/or end wall modules at the same angle as the top chord of the trusses to provide a flush support for the roof sheathing, parallel and in the same plane with the purlins. A high strength tensile load path is thus established through steel structure from the foundation through the frame to the roof for resisting high wing loading and shaking forces of earthquakes. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The invention and its many attendant objects and advantages will become better understood upon reading the following description of the preferred embodiment in conjunction with the following drawings, wherein: 
     FIG. 1 is a perspective view of one end of a two-story building frame made in accordance with this invention; 
     FIG. 2 is a cross sectional elevation from the inside of the building frame shown in FIG. 1; 
     FIG. 3 is a perspective view of a top story building frame wall module for use in buildings made in accordance with this invention; 
     FIG. 4 is a sectional perspective of a portion of the building frame shown in FIG. 1 from the inside with only the first story modules erected; 
     FIG. 5 is a sectional perspective of a portion of the building frame shown in FIG. 1 from the inside, with the first and second story modules erected; 
     FIGS. 6 and 7 are perspective views of the outside and inside, respectively, of a window wall frame module used in the building frame shown in FIG. 1; 
     FIGS. 8 and 9 are perspective views of a door wall frame module for a building frame in accordance with this invention; 
     FIG. 10 is a perspective view of an anchor bracket holding the base of two adjacent wall modules in accordance with this invention; 
     FIG. 11 is a perspective view of the anchor bracket shown in FIG. 10; 
     FIG. 12 is a sectional elevation of a second story joist and bottom-to-bottom anchor bracket arrangement in accordance with this invention; 
     FIG. 13 is a plan view of structural corner connection for a building frame in accordance with this invention; 
     FIG. 14 is a plan view of an alternative structural corner connection for a building frame in accordance with this invention; 
     FIG. 15 is a perspective view of a portion of a building frame in accordance with this invention showing the details of the hip roof supporting structure; 
     FIG. 16 is a perspective view of the structure shown in FIG. 15, with the purlins and ridge cap attached; and 
     FIG. 17 is a schematic elevation of a portion of a modification of the frame module shown in FIG. 3, showing how welding plates can be used to reduce cutting and welding time. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning now to the drawings, wherein like reference numerals designate identical or corresponding parts, and more particularly to FIGS. 1 and 2 thereof, one end corner of a two-story building frame  20  is shown having a peripheral wall (shown only partially) supporting a roof truss structure. The peripheral wall is made of two end walls  22  (only one of which is shown in FIG. 1) connected at their ends to ends of two side walls  26  (a portion of only one of which is shown in FIG.  1 ). The upper portions of the side walls  26  support opposite ends of a plurality of main trusses  28  spaced apart along the side walls at regular intervals, and the end walls  22  support one end of a plurality of hip roof jack trusses  30 , the other ends of which are supported on the main trusses  28  as will be described in more detail below. A plurality of purlins  32  are attached to the trusses  28  and  30  for supporting roof sheathing  34 . The peripheral wall may be secured to a building foundation  36  by anchor brackets  38  bolted to the foundation by anchor bolts  40  or the like, described in detail below. 
     The top story of the end walls  22  and the side walls  26  are assembled from a plurality of top wall modules  44 T, shown in FIG. 3, which are fabricated off site and trucked to the building site where they are bolted together as the top story of the building frame, shown in FIG.  1 . The lower story of the end walls and sides walls are likewise assembled from a plurality of lower story wall modules  44 L as shown in FIG.  4 . The modules  44  are made in a welding shop from lengths of rectangular metal tubing, welded together at precisely 90° corners so that the assembled building frame is perfectly true and square when bolted together. The tubing is preferably commercially available 2″×2″ square steel tubing having a wall thickness of 14 gauge, or 0.083″, ASTM-A-500 with a yield strength of about 50 KSI and a tensile strength of about 55 KSI. Naturally, other materials could be used, but this material is preferred because it is widely available from many sources at low cost and in various wall thicknesses and dimensions for different strength requirements. The gauge is selected based on the strength requirements of the building frame and will normally be within the range of 7-16 gauge. 
     The modules are preferably welded together on a welding jig that holds the lengths of tubing at the desired 90° within about 2°, or preferably with about 1° tolerance. Care should be taken to tack weld the entire module before completely welding the junctions to avoid heat distortion of the assembly. TIG welding has been found to produce clean welds that do not require de-slagging and also minimize heat input into the junction. If enough welding jigs are not available for the desired production rate, the first module may be made on the welding jig and the other identical modules may be made on top of the first as a pattern. 
     The preferred standard wall modules  44 , are exactly eight feet square, although the dimensions can conveniently be varied for different house designs if desired. The modules may be dimensioned to use standard interior wall board, such as that commonly sold in 4′×8′ panels, so the interior may be finished without extensive cutting of the wall board. The top story wall module  44 T shown in FIG. 3 includes two upright end members  40  and three longitudinal or girt members  42   u ,  42   m  and  42   b  welded between and spanning the end members  40 . The upper girt member  42   u  is welded atop the ends of the two upright end members  40 ; the lower girt member  42   b  is welded flush with the bottom of the end members  40 ; the middle girt member  42   m  is welded between the upright end members  40  intermediate the upper and bottom girt members  42   u  and  42   b , all at 90° corners. 
     As shown in detail in FIG. 3, an internal diamond shear brace is provided, having a 45° brace  43  welded to an upright end member  40  and the upper or bottom girt members  42   u  or  42   b , across each corner. The internal placement of the diagonal braces  43 , within the frame defined by the two upright end members  40  and the upper and bottom girt members  42   u  and  42   b , ensures that light gauge elements, to be described below, can be attached to the inside and outside faces of the frame module  44  without special cutting or other costly operations. A third upright member  41  may be welded midway between the two upright end members  40  at the apex of the upper and lower diagonal braces  43  for additional vertical load bearing capacity if the building design requires the additional strength. The diamond shear module shown in FIG. 3 is used in the peripheral wall  20  in all modules that do not have a window or door opening to provide strength and stiffness in the plane of the wall section for resistance against deflection toward a parallelogram shape under wind loads or lateral shaking during an earthquake. Because this invention can be used in buildings as high as six stories, shear bracing is added for resistance to shear distortion as well as flexural distortion due to bending as a cantilever, so this strengthening minimizes not only threats to the safety of the occupants but also to the serviceability of the building after the windstorm or earthquake. 
     Two upstanding stub members  45 , made of 4″ lengths of the same 2″×2″ steel tubing, are welded to the upper girt member  42   u  of the wall modules  44 , and an eve strut  46  is welded between them about 2″ above and parallel to the upper girt member  42   u . The stub members are each off-set from the outer edge of the end members  40  by about 1″, leaving a pocket  48 , shown in FIGS. 1 and 5, between adjacent stub members  45  on adjacent wall modules  44  for receiving end portions of the trusses  28  and  30 , as will be described in more detail below. The eve strut  46  stiffens the connection of the trusses  30  to the wall modules  36  in the pocket  48  and allows shear stresses exerted by the trusses on the stub members  45  to flow through the modules  44  from one side to the other. 
     The pocket  48  may be made deeper by using longer stub members  45 , for example, by using 6″ long stub members  45  instead of the 4″ long ones. The longer stubs  45  raise the eve strut  46  to about the height of the roof sheathing, allowing the sheathing to be attached directly into the eve strut. Attachment of the roof sheathing to the eve strut  46  as shown in FIG. 1 adds to the diaphragm shear strength of the roof system. 
     To facilitate attachment of the roof sheathing  34  to the eve strut  46 , the eve strut  46  is attached to the stubs  45  at an angle canted to correspond to the angle that the upper chord of the roof trusses lies. The depth of the pocket  48  is selected to allow the under surface of the eve strut to lie flush with the top surface of the top chord of the roof trusses, so the eve strut lies in the same plane as the purlins  32  attached to the trusses  28 . Attachment of the roof sheathing to the eve struts  46  by self-drilling/tapping screws or the like is then the same as attaching the sheathing to the purlins  32 . The attachment of the roof sheathing  34  directly to the eve struts  46  also increases the shear coupling between the roof and the building walls. 
     For buildings that do not have a hip roof, the wall modules for the end wall are identical to the side wall modules  36  except that the stub members  45  and the eve strut  46  are not used, so the upper girt member  42   u  is the topmost structural member on the end wall modules. This enables the lower chord of the end trusses to lie directly atop and be fastened to the upper girt members  42   u  of the end walls. 
     The lower story wall modules  44 L shown in FIGS. 1 and 4 use the same basic welded tubing design described above in conjunction with FIGS.  3  and  6 - 9 , but instead of the eve strut and truss pocket arrangement atop the upper girt member  42   u , a wall extension  50  is welded for attachment of the second and higher story floor joists  52 , as shown in FIGS. 2,  4  and  5 . The wall extension  50  includes several vertical risers  52  welded atop the upper girt member  42   u , and a top tube  54  welded to the top of the vertical risers  52 . A series of joist hangers  56  is welded between the top tube  54  and the upper girt member  42   u  for supporting floor joists  58 , as shown in FIG.  5 . The hard attachment of the joists  58  between opposite walls of the building frame stiffens the frame against “oil can” diaphragm flexing of the side and end walls of the building frame. 
     Typical door and window wall modules, shown in FIGS. 6-9, do not normally include the diagonal shear bracing shown in the wall panel shown in FIG. 3 because the assembled wall frame with one or more diamond shear bracing modules as shown in FIG. 3 provides the shear stiffness for the entire wall. 
     Light gauge elements are welded to the frame modules  44  for attachment of exterior siding and interior finishing such as wallboard, paneling or the like. The light gauge elements include inside studs  60 , exterior furring or stringers  62 , bottom track  64 , and interior top angle  66  and, for the top story modules  44 T, exterior top angle  68 . The inside studs  60  and the inside flange  61   i  of the bottom track  64  provide light gauge metal supports to which the interior wallboard can be attached by wallboard screws or the like. The ceiling wallboard and the top of the wall wallboard are attached to the interior top angle  66 . The exterior furring  62  and the exterior flange  61   e  of the bottom track  64  provides attachment surfaces for attachment of exterior siding to the modules  44 . On the top story module  44 T, the exterior siding is attached at the top to the flange of the exterior top angle  68 . The angle surface of the exterior top angle  68  provides an attachment surface for the soffit. The interior sheet metal elements are typically about 22 gauge, on the order of 0.034″. The exterior sheet metal elements are typically about 20 gauge, on the order of 0.040″. These gauges provide the desired stiffness and ease of welding to the tubing of the frame modules while allowing ready penetration by drilling screws during attachment of the interior wallboard and exterior siding. 
     The anchor brackets  38  by which the wall modules  44  are fastened to the building foundation  36  are shown in detail in FIGS. 10 and 11. Each anchor bracket  38  includes two side plates  70  having a square cut-out  72  at the bottom outside corner. The two side plates  70  are welded to opposite ends of a short length of angle iron  74  having a round or elongated hole  76  in the horizontal leg of the angle iron  74 . The square cut-outs  72  form a step that allows the bracket to sit on the bottom track  64  adjacent the bottom girt member  42   b  with the two side plates bracketing adjacent upright members  40  of adjacent modules  44 . A pair of bolts  80  extends through two holes  82  in each of the side plates  70  and corresponding holes in the adjacent upright members  40  of the adjacent modules  44  to secure the modules  44  together. An anchor bolt extends from the foundation through a hole in the bottom track  64  and through the hole  76 , and a nut secures the anchor bracket to the anchor bolt and the foundation  36 . 
     The anchor brackets  38  are also used in a bottom-to-bottom arrangement, shown in FIG. 12, to secure vertically adjacent wall modules  44  together through the base floor deck  85  of the floor between the two wall modules  44 . A bolt  88  extends through the holes  76  in the two anchor brackets  38  to clamp the base floor deck between the upper and lower wall modules  44   
     The corners at the junction of the end wall frames  22  and the side wall frames  26  are formed by a corner structure  90 , shown in FIG.  13 . The corner structure  90  includes a base plate  92  and a top plate  94  (not shown), and two vertical tubes  96  and  98  arranged edge-to-edge and welded in that position to the top and bottom plates  92  and  94 . The adjacent edges of the vertical tubes  96  and  98  are stitch-welded along their length. The adjacent ends of the adjacent end and side wall frames  22  and  26  are attached to the tubes  96  and  98 , respectively to provide a strong rigid corner structure. 
     A flanged right-angle exterior light gauge element  100  is attached around the outside of the corner structure  90  to provide an attachment structure for the exterior siding at the corner. The flanges  102  provide a stand-off for the attachment surface of the element  100  equal to the stand-off of the exterior light gauge furring  62 , so the exterior siding lies perfectly flat along the outside of the building. An interior W-shaped light gauge sheet metal element  110  attaches to the inside surfaces of the adjacent modules of the adjacent end and side wall frames  22  and  26 . Attachment surfaces  115  for attachment of the interior wallboard are off-set from the surfaces of the tubing by stand-off portions  117  that are the same width as the interior studs  60 , so the wallboard is supported perfectly flat at its junction at the corner. 
     Another version of the corner structure is shown in FIG.  14 . In this form, the corner structure  120  has a length of heavy angle iron  122  welded between the top and bottom plates  92  and  94  instead of the two edge-to-edge tubes  96  and  98  as shown in FIG.  13 . In all other respects, the corner structures  90  and  120  are structurally identical. 
     The wall modules  44  can be made different sizes for different building designs, but it is most economical to use the same wall modules and adjust the wall lengths by adding short end modules  125  to provide the added increment of wall length to satisfy the exact wall length desired. The short wall end modules  125  shown in FIGS. 1 and 2 are structurally alike the standard wall modules  44  except, of course, they are shorter. The diagonal bracing  43  is preferably designed to lie aligned with and at the same angle as the shear bracing  43  in the adjacent module to provide continuous shear bracing to the corner, but shear bracing will not always be needed in the short end modules  125 . 
     After the wall modules  44  and trusses  28  and  30  have been fabricated in the shop and the foundation has cured, the wall modules and trusses are trucked to the building site and unloaded around the foundation at about the positions they will occupy on the foundation. The lower story modules  44 L can be tipped up with a small crew and bolted together with bolts  80  extending through aligned holes in the upright end members  40  at the top and at the bottom adjacent the lower longitudinal member  42   b  through the side plates  70  of the anchor bracket, with an additional bolt  80  at about the mid-level height of the end members  40 . The corner modules are first fastened together to the corner structure  90  or  120 , and then and the anchor brackets are fastened to anchor bolts in the foundation. The intermediate modules are then added and secured with bolts. When all the wall modules have been erected and connected together, the bolts  106  are tightened. 
     When all the lower story wall modules  44 L have been bolted together to complete the peripheral wall  20  for the first story, second story floor joists  58  are lifted into place and bolted to the joist hangers  56 . Base floor deck  85  is laid on and attached to the joists  58  out to the outer periphery of the wall frame  20 . Now the second story wall modules  44 U are lifted into place and attached together in the same manner as the ground story wall modules  44 L were attached. In the case of the building shown in FIG. 1, the second story frame modules have the joist pockets  48  and eve struts since that will be the top story. If the building were a three story or higher building, additional stories of modules  44 L would be installed. 
     The anchor brackets  38  are attached to the adjacent upright frame members  40  of adjacent frame modules  44   u  and the vertically adjacent upright frame members  40  of adjacent frame modules  44 L, and the bolt  88  is inserted through the aligned holes  76  in the anchor bracket and a hole drilled in the base floor deck  85 . The bolts  88  of all the installed anchor brackets  38  are tightened by torquing the nuts  89  on the bolts  88  when the modules have all been erected and bolted together. 
     After the wall frame is erected, the trusses  28  are lifted onto the top of the peripheral wall  20  for attachment thereto. The center trusses  28  are attached first by laying the opposite ends of the bottom chord in the chosen truss pocket  48 . The other center trusses  28  are likewise fitted into the pockets  48  between the upstanding stub members between adjacent side wall modules  36 . A bolt is inserted through a hole that was pre-drilled in the shop through the upstanding stub members  44  and preferably also through the lower chord of the trusses  28 , and the bolt  107  is tightened to secure the trusses to the peripheral wall  20 . Alternatively, the upright stub members  44  could be predrilled and the truss lower chord  96  back drilled when it is in place to avoid the possibility of slight misalignment of the holes when the parts come together. The bolting of the trusses into the pockets  48  through the upright stub members  44  secures the roof to the peripheral wall  20  and, together with the anchoring of the peripheral wall  20  to the foundation, anchors the roof to the foundation against displacement due to wind loads or differential movement of the foundation and the building during an earthquake. 
     The hip roof trusses, shown in FIG. 15, are designed to support a roof lying at an angle to the crest of the “main” roof supported by the lateral trusses  28 . The hip roof supports roof purlins that extend out to the junction with the main roof along a hip ridge. A series of jack trusses  30  lying perpendicular to the planes of the main trusses  28  are supported at one end on the end wall frame  22 , and are supported at their other ends at intermediate positions along a lateral girder truss  29 . The center jack truss  30  has an extension  31  that spans the distance between the lateral girder truss  29  and the last main lateral truss  28  adjacent the junction with the hip roof. 
     Two hip beams  130  and  132  are provided for supporting ends of the main roof purlins and the hip roof purlins at the hip ridge. Each hip beam  130  and  132  lies generally adjacent and parallel to the hip ridge. The hip beam  130  has an upper surface lying in the plane of the main roof and the hip roof beam  132  has an upper surface lying in the hip roof plane. The hip beams are each attached adjacent one end thereof to the underside of the eve strut  46 , and are attached adjacent the other end thereof to a truss. 
     The hip beam  132  is made of two pieces, each supported at adjacent inner ends thereof on the outermost jack truss by way of attachment bars spanning top and bottom surfaces of an upper chord of the jack truss  30  at the inner ends of the hip beam pieces. In this way, the hip beam is supported at the same angle as the jack truss for flush attachment of the purlins to the hip beams and the jack trusses. The hip beam  130  also has two parts, each having an inner end. The inner ends of the two parts are supported on the girder truss with upper surfaces of the hip beam  130  flush with upper surfaces of the girder truss so the purlins supported at their ends by the hip beam  130  lie in the plane of the main roof. 
     After all the trusses  28  and  30  have been bolted into the pockets  48 , the purlins  32  are inserted between and fastened to pairs of L-shaped brackets  122  prewelded onto the upper chord  94  of the trusses, and are fastened thereto by nuts and bolts or by self-drilling/tapping screws through each bracket. The purlins  32  lie atop the trusses  30  and connect them together. A sheet metal ridge angle piece  135  is attached to the adjacent ends of the purlins at the hip ridge, as shown in FIG.  16 . Roof sheathing  124  is laid over and screwed to the purlins, as shown in FIG. 1, and the roof is sealed and shingled in the usual manner. 
     A foaming insulating material is applied against the inside surface of the exterior siding and is allowed to expand around the wall frame, sealing and insulating the wall. After setting, the foam is sawed off flush with the surface of the interior studs  60  providing sound dampening as well as thermal insulation. The spacing of the wallboard and the extersiding away from the structural frame provides excellent thermal insulation. The wall, with a double layer of wallboard on both sides, was tested in accordance with the Standard Fire Tests of Building Construction and Materials, ANSI/UL263. After three and one half hours the test was terminated with the wall still intact. 
     The invention thus enables the low cost construction of a house with design capabilities of meeting the design needs of multiple requirements without major redesign. In areas where heavy snow loads can be expected, the pitch angle of the trusses can be increased to any desired angle to increase the load bearing strength and the snow shedding capability of the roof. In earthquake prone areas, the diagonal shear panels give redundant load sharing capability. The roofing material may be selected for minimum weight to minimize the inertial forces so the house moves more like a rigid unit rather than a flexible vertical cantilever. This will minimize the damage to the building caused by differential movement of the foundation and the roof so that the building will remain serviceable after the earthquake. The metal frame building is inherently immune to attacks by termites and carpenter ants as well as mold and mildew, and is inherently resistant to fire damage. 
     Obviously, numerous modifications and variations of the preferred embodiment described above are possible and will become apparent to those skilled in the art in light of this specification. For example, the welding of the diagonal braces  43  can be by way of weld plates  140  instead of cutting the ends of the tubes  43  to fit flush against the inside surface of the frame members  40 ,  42   u  and  42   b , thereby saving cutting and welding time and producing a product that is as good or better. Many functions and advantages are described for the preferred embodiment, but in some uses of the invention, not all of these functions and advantages would be needed. Therefore, we contemplate the use of the invention using fewer than the complete set of noted functions and advantages. Moreover, several species and embodiments of the invention are disclosed herein, but not all are specifically claimed, although all are covered by generic claims. Nevertheless, it is our intention that each and every one of these species and embodiments, and the equivalents thereof, be encompassed and protected within the scope of the following claims, and no dedication to the public is intended by virtue of the lack of claims specific to any individual species. Accordingly, we expressly intend that all these embodiments, species, modifications and variations, and the equivalents thereof, are to be considered within the spirit and scope of the invention as defined in the following claims, wherein we claim.

Technology Classification (CPC): 4