The OSB roof sheathing, as illustrated in Figure 3, serves to transfer gravity load (i.e., dead, live, and snow loads) and wind suction to roof framing members. Typical I-joist and LVL (courtesy Timber Rock Homes). The sole plate is attached to the foundation wall with cast-in-place anchors such as J-bolts or post-installed anchorage that must be drilled after the concrete has had time to cure, such as expansion anchors, epoxy anchorage, or screw type. The 26 designation refers to a wood framing member with a nominal 50.8mm (2inch) width and a 152.4mm (6inch) depth. Additionally, these two cases must be compared to the minimum load case described in ASCE 7 Section 28.6.4. Lastly, wood-framed construction has been well documented in the USA, and many design aids are available. Another issue to consider when specifying wall bracing is the stud spacing. Attachment requirements of the sheathing to roof trusses are governed by the greater of the wind uplift force or the shear transfer requirement of the connection. This is typical of an initial home design. Floor, wall, roof and stair assemblies are each made up ofspecific dimensional wood components, similar to a skeleton. These components are fastened together to form the structure and allow the interior spaces to function as desired. Results were within 1% of each other between the two analysis packages. This is often costlier than the extra amount of sheathing required for the WSP method. The design of residential girders involves assumptions regarding the bracing of the beam. Dead load is the load that is permanently and continuously applied to a structure. Holes in dimensional lumber typically require structural analysis and stress evaluation as they become large relative to the depth of the joist or beam. Figure 8 shows an example of typical adjustable columns. According to IRC Table R602.3(1), the sheathing is required to be attached to the truss framing with 63.5mm (2inch) 8D common nails spaced at 152.4mm (6inch) on center (O.C.) Interior loads are transferred by the intermediate girder through columns to concrete pad footings. For WSP methods panel lengths between 0.914 and 1.22m (36 and 48inches) are allowed but must be adjusted per IRC Table 602.10.3. ; however, it is more typical for the studs to be spaced at 406.4mm (16inch) O.C. or a keyway to be provided in this instance since unbalanced backfill height exceeds 1.22m (4foot). Some guidance is typically specified in the manufacturer literature. Engineers typically become involved with design items such as foundation design, steel framing design, or engineered product specification. In this chapter, the design of a typical light-framed home is discussed. In this case, there are three pad footings required to support the interior central steel girder. These documents are adopted by the 2015 IRC and often lead to more economical designs when compared to the requirements of the IRC. Dead loads are listed in Tables 1, 2, 3. This involves specifying the connection to wall system below. By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers. The designs will include only the effects of dead loading, floor live loading, roof live loading, snow loading, and wind loading. Contact our London head office or media team here. The maximum loading, as reported by the manufacturer, is a factored allowable ASD load capacity (Ra). With a prescriptive approach, the prescribed anchor bolts are assumed to adequately transfer both the overturning actions and horizontal actions generated by the wind. Engineers will conduct their analysis based on requirement set forth in the IRC, IBC if necessary, and ASCE 7-10 minimum design loads for buildings and other structures (ASCE 7) [4] [ASCE stands for American Society of Civil Engineers]. Additionally, lumber joists are only available in certain lengths. For this particular home design case, the maximum ASD girder reaction is 80.5kN (18.1kip). Note: in this figure, the following notation is used: V for shear force, T for tension force, C for compression force, l and L for Span length, h and H for height, for wind pressure, for wind load per unit length, and Vw for shear per unit length. For example, the ASD approach will be used for wood design, whereas the LRFD approach will be used for concrete foundation design. For this design, two load cases must be evaluated because the roof pitch is between 25 and 30 degrees. The typical residential MWFRS system is composed of a system of flexible diaphragms and shear walls. The IRC prescribes the maximum allowable deflection of structural members and assemblies. When the truss drawings are received by the home designer, the loads to the structure, based on the analysis conducted by the truss designer, are typically listed on the engineered truss plans. The gravity load-bearing elements of the wall system presented here are the 26 dimensional lumber studs and the top and bottom plates (or sole plate). When using the IRC approach, the prescribed nailed connections are assumed to be adequate to transfer the overturning shear forces shown in Figure 11 to the foundation. The design drawings are shown in the Appendix.
The TJI 28.6mm (1 1/8inch) engineered rim board will be used for the perimeter of the floor system. The process for manufacturing engineered wood makes it more expensive than dimensional lumber, but reduces waste and delivers a product that is significantly stronger and more stable, and more uniform in shape and size. Unlike dimensional lumber, both hardwood and softwood from abundant fast growth tree species are used to manufacture engineered wood. The process of manufacturing is done under tight industry standards. These types of girders are much stronger than dimensional lumber beams and are necessary in many instances because of the longer allowable engineered I-joist spans and homeowner request for open basement floor plans. This connection is subject to a total shear load of 10.7kN (2400lbf) when the wind is applied perpendicular to the gable end. The envelope and structural components are typically selected by the architect, builder, or homeowner from design tables within the code. If ignored, this could have led to the undersizing of both adjustable column and pad footing. SCM Section J10.7 requires all unframed girder ends to have a pair of transverse stiffeners if unrestrained. Open Access is an initiative that aims to make scientific research freely available to all. Dry materials are used as wood strands or veneers, which are adhered and compressed into large billets then sawn into standard lengths, widths and thicknesses. Engineered wood products are a high quality substitute for dimensional lumber. They include laminated veneer lumber (LVL), parallel strand lumber (PSL), laminated strand lumber (LSL), wood I-joist and glue laminated beams. An example of a typical truss connector is shown in Figure 12. The manufacturer will then design the floor system according to the requests of the homeowner and designer. The combined pressure will be applied to only the windward side of the structure. The gravity loads of importance for residential structures are dead load (DL), floor live load (LL), roof live load (RL), and snow load (SL). In addition, the opposing soil exterior lateral loading tends to offset the small amounts of eccentricity created by above-grade wall offsets, so in practice the effects of above-grade wall offsets are generally ignored for wall footing design. If using a single top plate or studs spaced at 609.6mm (24inch) O.C., then the joists or trusses must either be directly above the stud or within 25.4mm (1inch) of the stud according to IRC Section R602.3.2. The following components are found in the traditional roof frame: Modern roof frames can be constructed with roof trusses. A roof truss is a manufactured, engineered wood assembly that includes diagonal top chords, a horizontal bottom chord, and vertical and/or diagonal webs or braces between the top and bottom chords. Each adjacent member is face connected or joined with metal toothed plates or gussets. In this study, only a few of the typical critical connections for the structural system were specified. The connections are typically nails, and the nail sizes vary between 8D and 16D based on the detail. Small sizes tend to have stability issues and can be susceptible to local buckling problems caused by larger point loads. The garage was not analyzed, but the procedure would be the same. This made the need for a splice at an internal bearing wall or beam a very common occurrence. Note: the arrows show loads, and small rectangle with x inside indicates the cross section of wood member. The concrete foundation wall for the main structure in this example has an unsupported height of 2.44m (8foot) and will be subjected to approximately 2.13m (7foot) of unsupported backfill when in service (Figure 9a). These loads are typical for residential design and were largely derived from ASCE 7 Table C3-1. For this example home design, a central steel girder will be used to collect the floor loads and transfer to pad footings in the center of the basement. The IRC and IBC also permit designers to refer to the 2015 AWC Wood Frame Construction Manual(WFCM) [5] for an alternative prescriptive or engineered approach [AWC stands for American Wood Council]. According to ASCE 7 Table 3.2.1, this is representative of a type GC soil (unified soil classification), which is described as a clayey gravel, poorly graded, gravel, and sand mix. SST A21 has a design capacity of 1.09kN (245lbf) per connector; therefore, the required number of connectors will be 10.7kN/1.09kN, which gives approximately 10 connectors. The American Concrete Institute (ACI) 332-08 [13] and ACI 318-14 [14] are used as references for this design. It is possible that 15.1mm (19/32inch) or 15.9mm (5/8inch) sheathing could be used, but spans are restricted to 508mm (20inch). The improved stability and increased stiffness of I-joists allow designers to consider larger spacing for the floor joists. The following major aspects are discussed in this chapter: Provide introductory material such as the description of the home to be designed, applicable design codes, and external loading assessment for residential structures. Attics defined as the unfinished area between the roof and the ceiling of the floor below. When specifying headers, the designer may choose to specify larger headers in some locations for consistency sake. The garage and the main building can be somewhat treated as separate buildings for the purposes of MWFRS design. Since the girder is a continuous beam having multiple spans, ASCE 7 Section 4.3.3 requires the consideration of pattern loading. This reduced the demand/capacity ratio to the acceptable level of 0.698. For this example, it will be assumed that the load from the exterior wall will act concentrically on the footing. Sliding on the second floor is resisted by the nailed connection between the bottom plate and the floor assembly. Clients of S&A Homes can select this floor plan from an array of floor plans and make slight variations to it if desired. How? As noted before, much of the wood-framed structural design can be accomplished using design aids. The only lateral load being considered for this study is the wind loading. If an engineered design or the WFCM prescriptive approach is used to specify shear wall panels, then structural connectors must be specified to transfer these overturning forces. For this design, the equivalent soil pressure will be estimated at 2.15kn/m2 per linear meter (45lbf/ft2 per linear foot). Publishing on IntechOpen allows authors to earn citations and find new collaborators, meaning more people see your work not only from your own field of study, but from other related fields too. It should be noted that the required moisture management and thermal envelope components are not shown for clarity in the figure. ASCE 7 is the standard referenced in the 2015 IRC, and therefore this version will be referenced in this study. This is typically the extent of a structural engineers involvement in residential design other than specialized situations not covered by the IRC and occasionally foundation design. Initially, the applicable building and material codes were introduced and relevant provisions discussed. The garage wall foundation walls are all 0.91m (3feet) in height and have no unbalanced backfill. In this case, it turns out that applying live loading to spans 1, 2, and 4 only produced the largest internal moment of 31.5kN-m (23.3kip-ft) in the beam. All three columns will be specified for this maximum loading. For most residential designs, geotechnical exploration and lab testing are cost prohibitive, and therefore soil pressures must be assumed. An owner may choose to involve the engineer to improve quality or economy of the home design. The default value of 71.8kN/m2 (1500lbf/ft2) is used for the soil bearing capacity, as in the strip footing design. Wood roof trusses must be designed in accordance with IRC Section R802.10. Additionally, the erection of a wood-framed structural system is familiar to most and does not require excessive amounts of specialized knowledge or tools. Another consideration for girder sizing is live load pattern loading. Steel girders are often chosen over manufactured lumber girders when girder spans are long, head room in the basement is a premium, or steel is readily available. Unless noted otherwise, the S&A Homes dead load criteria will be used for the wood-framed design of this home. Adjustable columns are readily available at almost any hardware stores and can be adjusted in height to match site conditions by the contractor. In order to construct a single-family dwelling, the homebuilder must first apply to the local code office for a building permit. The main serviceability criterion considered in the design of residential homes is deflection. Limited storage refers to non-habitable attic space greater than or equal to 1.07m (42inch). This is a reasonable assumption because basement walls are typically restrained from translation at the top and bottom by the first floor assembly and the basement slab, respectively. Residential structures in ordinary situations are designed to resist both gravity loads and lateral loads. Live load deflections are often limited to L/480 (beam span/480). The size of wood framing members is standard regardless of species and is typically stocked at lumber yards innominal widths of 2 to 12 inches, increasing in2 inch increments. Typically, there are sufficient nails engaged to resist the shear force. According to IRC Table R503.2.1.1(1), 11.1mm (7/16inch) roof sheathing (24/16 span rating) is acceptable for this example. The top plate serves three purposes: (1) a chord for the MWFRS, (2) a strut between shear panels in a wall line, and (3) a means to transfer gravity loads to the stud from the joists and trusses. Because this home is categorized in seismic design category A, Section 602.10.1 allows for different methods to be used along different wall lines. The items specified from the IRC in this wood-framed section are based on compliance with this table. The following list identifies and describes each component within each type of assembly. For this reason, most residential designers use the IRC to specify shear panels and their fastening system. Raw Material Demand-Supply and Policy Recommendati Department of Architectural Engineering, Penn State University, USA, Department of Civil and Environmental Engineering, Penn State University, USA. Brief introduction to this section that descibes Open Access especially from an IntechOpen perspective, Want to get in touch? Because the unbalanced backfill is less than 1.22m (4feet), Section 6.3.4 allows for the use of a clean construction joint versus dowel rods. Light-wood framing construction techniques have been traditionally used in America for the construction of single-family residences. This chapter presented a complete design of a typical US single-family home made of conventional wood-frame system. Pattern loading was significant in this example. A W8x18 steel girder, with a design moment capacity of 86.5kN-m (63.8kip-ft), is more than adequate to resist the internal moment of 31.5kN-m (23.2kip-ft) for the controlling load case. Because the concrete will be exposed to weathering, it must be air entrained, having an air content of 6% plus or minus 1.5%. Double joists often require padding at connections and sometimes bearing, which is usually OSB, to compensate for the space between the web and flanges. Design of light-framed single-family homes is typically conducted by an architect or construction contractor using prescriptive building codes. As shown in Figure 4, I-joists have become popular and cost-effective in the residential home construction market. 26 wood studs at 406.4mm (16inch) O.C. at both the perimeter and intermediate locations. The floor plan has features typically seen in modern homes. (SCM)in Chapter B3.6, F1 (2) [12] and Appendix 6.3 all require that girders are restrained against rotation about their longitudinal axis at the points of support unless it can be shown that the restraint is not required. Structural assemblies such as the roof, floors, and walls are generally constructed with nominal 50.8mm (2 inch) lumber members ranging in nominal depths from 101.6 to 304.8mm (412inches) and sheathed with structural wood panels for stability and security, such as oriented strand board (OSB) or plywood. If it is assumed that the columns do not provide adequate bottom flange support, then these negative moment regions would be destabilizing, and since inflection points are not typically recognized as a brace point (SCM Appendix 6.3), the unbraced length would have to be taken as the entire beam length of 11.0m (36feet), which would require a very large section. In the State College area, seismic loading does not typically control the design of structural components. The required bracing for the garage/main house common wall will be added directly to the first floor north wall. Both the IRC and ACI 332 allow for the use of 152.4mm (6-inch)-thick footings (assuming adequate strength), but the developer in this case prefers to use 203.2mm (8-inch)-thick footings. By Cecilia Mark-Herbert, Elin Kvennefeldt and Anders HeadquartersIntechOpen Limited5 Princes Gate Court,London, SW7 2QJ,UNITED KINGDOM, External load determination and serviceability requirements. As for the building-to-foundation connection, there is no reason to expect an extraordinary loading at this junction, so anchor bolts are specified according to IRC Chapter R403.1.6. around sheathing edges and 304.8mm (12inch) O.C. stud spacing; however, the builder prefers a 11.1mm (7/16-inch)-thick OSB panel, which is required to be fastened to framing using 8D common nails at 152.4 (6inch) O.C. ACI 332 also prescribes 12.7mm diameter (inch) dowel rods at a maximum of 609.6mm (24inch) O.C. Data for individual permutations is not able to be extracted. The flexible roof or floor diaphragms, as shown in Figure 11b, act similar to a deep beam and distribute the wind load as reactions to the exterior walls parallel to the wind loading (Figure 11c) and distribute to the stiff structural shear panels within those walls by direct diaphragm connection or strutting. While other structural systems are becoming increasingly available, the wood-frame system is still the dominating system as in the USA lumber is readily available at highly competitive process. A structural engineer can assist, if needed, with design items not within the scope of the building code or if alternative design approaches are required. For floor areas known to have ceramic tile floor covering, increase load to 0.96kN/m2 (20lbf/ft2). The amount of restraint provided by the adjustable column, which is typically four bolts through the bottom flange, may need a detailed analysis because of the slenderness of the columns. Typically, the gravity loads govern the thickness choice of subflooring, and the shear requirements dictate connection to joists [8]. The sheathing can be used with or without edge support at 609.6mm (24inch) spans with an allowable live load of 1.92kN/m2 (40lbf/ft2), and a total allowable load of 2.39kN/m2 (50lbf/ft2), which is less than the 1.44kN/m2 (30lbf/ft2) snow loading plus 0.57kN/m2 (12lbf/ft2) roof dead load. This allows for shallower floor assemblies, longer spans, and higher ceilings. I-joists have several advantages over dimensional lumber joists, one of which is a greater span-to-depth ratio. Design the home using a wood-framed platform system. Limit I-joist deflection ratio to length/480. Rafter framing is accomplished in the same manner as platform framing. The OSB roof sheathing, as illustrated in Figure 3, serves to transfer gravity load (i.e., dead, live, and snow loads) and wind suction to roof framing members. Typical I-joist and LVL (courtesy Timber Rock Homes). The sole plate is attached to the foundation wall with cast-in-place anchors such as J-bolts or post-installed anchorage that must be drilled after the concrete has had time to cure, such as expansion anchors, epoxy anchorage, or screw type. The 26 designation refers to a wood framing member with a nominal 50.8mm (2inch) width and a 152.4mm (6inch) depth. Additionally, these two cases must be compared to the minimum load case described in ASCE 7 Section 28.6.4. Lastly, wood-framed construction has been well documented in the USA, and many design aids are available. Another issue to consider when specifying wall bracing is the stud spacing. Attachment requirements of the sheathing to roof trusses are governed by the greater of the wind uplift force or the shear transfer requirement of the connection. This is typical of an initial home design. Floor, wall, roof and stair assemblies are each made up ofspecific dimensional wood components, similar to a skeleton. These components are fastened together to form the structure and allow the interior spaces to function as desired. Results were within 1% of each other between the two analysis packages. This is often costlier than the extra amount of sheathing required for the WSP method. The design of residential girders involves assumptions regarding the bracing of the beam. Dead load is the load that is permanently and continuously applied to a structure. Holes in dimensional lumber typically require structural analysis and stress evaluation as they become large relative to the depth of the joist or beam. Figure 8 shows an example of typical adjustable columns. According to IRC Table R602.3(1), the sheathing is required to be attached to the truss framing with 63.5mm (2inch) 8D common nails spaced at 152.4mm (6inch) on center (O.C.) Interior loads are transferred by the intermediate girder through columns to concrete pad footings. For WSP methods panel lengths between 0.914 and 1.22m (36 and 48inches) are allowed but must be adjusted per IRC Table 602.10.3. ; however, it is more typical for the studs to be spaced at 406.4mm (16inch) O.C. or a keyway to be provided in this instance since unbalanced backfill height exceeds 1.22m (4foot). Some guidance is typically specified in the manufacturer literature. Engineers typically become involved with design items such as foundation design, steel framing design, or engineered product specification. In this chapter, the design of a typical light-framed home is discussed. In this case, there are three pad footings required to support the interior central steel girder. These documents are adopted by the 2015 IRC and often lead to more economical designs when compared to the requirements of the IRC. Dead loads are listed in Tables 1, 2, 3. This involves specifying the connection to wall system below. By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers. The designs will include only the effects of dead loading, floor live loading, roof live loading, snow loading, and wind loading. Contact our London head office or media team here. The maximum loading, as reported by the manufacturer, is a factored allowable ASD load capacity (Ra). With a prescriptive approach, the prescribed anchor bolts are assumed to adequately transfer both the overturning actions and horizontal actions generated by the wind. Engineers will conduct their analysis based on requirement set forth in the IRC, IBC if necessary, and ASCE 7-10 minimum design loads for buildings and other structures (ASCE 7) [4] [ASCE stands for American Society of Civil Engineers]. Additionally, lumber joists are only available in certain lengths. For this particular home design case, the maximum ASD girder reaction is 80.5kN (18.1kip). Note: in this figure, the following notation is used: V for shear force, T for tension force, C for compression force, l and L for Span length, h and H for height, for wind pressure, for wind load per unit length, and Vw for shear per unit length. For example, the ASD approach will be used for wood design, whereas the LRFD approach will be used for concrete foundation design. For this design, two load cases must be evaluated because the roof pitch is between 25 and 30 degrees. The typical residential MWFRS system is composed of a system of flexible diaphragms and shear walls. The IRC prescribes the maximum allowable deflection of structural members and assemblies. When the truss drawings are received by the home designer, the loads to the structure, based on the analysis conducted by the truss designer, are typically listed on the engineered truss plans. The gravity load-bearing elements of the wall system presented here are the 26 dimensional lumber studs and the top and bottom plates (or sole plate). When using the IRC approach, the prescribed nailed connections are assumed to be adequate to transfer the overturning shear forces shown in Figure 11 to the foundation. The design drawings are shown in the Appendix.
The OSB roof sheathing, as illustrated in Figure 3, serves to transfer gravity load (i.e., dead, live, and snow loads) and wind suction to roof framing members. Typical I-joist and LVL (courtesy Timber Rock Homes). The sole plate is attached to the foundation wall with cast-in-place anchors such as J-bolts or post-installed anchorage that must be drilled after the concrete has had time to cure, such as expansion anchors, epoxy anchorage, or screw type. The 26 designation refers to a wood framing member with a nominal 50.8mm (2inch) width and a 152.4mm (6inch) depth. Additionally, these two cases must be compared to the minimum load case described in ASCE 7 Section 28.6.4. Lastly, wood-framed construction has been well documented in the USA, and many design aids are available. Another issue to consider when specifying wall bracing is the stud spacing. Attachment requirements of the sheathing to roof trusses are governed by the greater of the wind uplift force or the shear transfer requirement of the connection. This is typical of an initial home design. Floor, wall, roof and stair assemblies are each made up ofspecific dimensional wood components, similar to a skeleton. These components are fastened together to form the structure and allow the interior spaces to function as desired. Results were within 1% of each other between the two analysis packages. This is often costlier than the extra amount of sheathing required for the WSP method. The design of residential girders involves assumptions regarding the bracing of the beam. Dead load is the load that is permanently and continuously applied to a structure. Holes in dimensional lumber typically require structural analysis and stress evaluation as they become large relative to the depth of the joist or beam. Figure 8 shows an example of typical adjustable columns. According to IRC Table R602.3(1), the sheathing is required to be attached to the truss framing with 63.5mm (2inch) 8D common nails spaced at 152.4mm (6inch) on center (O.C.) Interior loads are transferred by the intermediate girder through columns to concrete pad footings. For WSP methods panel lengths between 0.914 and 1.22m (36 and 48inches) are allowed but must be adjusted per IRC Table 602.10.3. ; however, it is more typical for the studs to be spaced at 406.4mm (16inch) O.C. or a keyway to be provided in this instance since unbalanced backfill height exceeds 1.22m (4foot). Some guidance is typically specified in the manufacturer literature. Engineers typically become involved with design items such as foundation design, steel framing design, or engineered product specification. In this chapter, the design of a typical light-framed home is discussed. In this case, there are three pad footings required to support the interior central steel girder. These documents are adopted by the 2015 IRC and often lead to more economical designs when compared to the requirements of the IRC. Dead loads are listed in Tables 1, 2, 3. This involves specifying the connection to wall system below. By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers. The designs will include only the effects of dead loading, floor live loading, roof live loading, snow loading, and wind loading. Contact our London head office or media team here. The maximum loading, as reported by the manufacturer, is a factored allowable ASD load capacity (Ra). With a prescriptive approach, the prescribed anchor bolts are assumed to adequately transfer both the overturning actions and horizontal actions generated by the wind. Engineers will conduct their analysis based on requirement set forth in the IRC, IBC if necessary, and ASCE 7-10 minimum design loads for buildings and other structures (ASCE 7) [4] [ASCE stands for American Society of Civil Engineers]. Additionally, lumber joists are only available in certain lengths. For this particular home design case, the maximum ASD girder reaction is 80.5kN (18.1kip). Note: in this figure, the following notation is used: V for shear force, T for tension force, C for compression force, l and L for Span length, h and H for height, for wind pressure, for wind load per unit length, and Vw for shear per unit length. For example, the ASD approach will be used for wood design, whereas the LRFD approach will be used for concrete foundation design. For this design, two load cases must be evaluated because the roof pitch is between 25 and 30 degrees. The typical residential MWFRS system is composed of a system of flexible diaphragms and shear walls. The IRC prescribes the maximum allowable deflection of structural members and assemblies. When the truss drawings are received by the home designer, the loads to the structure, based on the analysis conducted by the truss designer, are typically listed on the engineered truss plans. The gravity load-bearing elements of the wall system presented here are the 26 dimensional lumber studs and the top and bottom plates (or sole plate). When using the IRC approach, the prescribed nailed connections are assumed to be adequate to transfer the overturning shear forces shown in Figure 11 to the foundation. The design drawings are shown in the Appendix.
