typical wood frame wall assemblies includebest stainless steel tubing cutter

For this design, only live load deflection limits will be considered. Considering LRFD combination 2, two-way shear (punching shear) with a demand/capacity ratio of 1.30 was the controlling failure mechanism for the concrete footing and required an increase in footing depth from 203.2mm (8inch) to 254mm (10inch). For example, the ASD approach will be used for wood design, whereas the LRFD approach will be used for concrete foundation design. SST A21 angles were considered for the gable end truss-to-top plate connection. An example would be the stair trimmer detail shown in Figure 5. The reactions are the connections with wall below. The structural wall panels, as shown in Figure 11d, provide the necessary shear resistance and transmit the loads vertically (overturning tension and compression loads at the corners of each structural panel) to the foundation though a system of hold-downs and connections. Unless noted otherwise, the S&A Homes dead load criteria will be used for the wood-framed design of this home. This connection is subject to a total shear load of 10.7kN (2400lbf) when the wind is applied perpendicular to the gable end. The assumption will be made that the footings are not exposed to weathering; therefore, ACI 332 prescribes 17MPa (2500psi) minimum compressive strength for the concrete. It may be possible to use 9.5mm (3/8inch) sheathing, but 11.1mm (7/16inch) thickness is more readily available and common in the locale. In this chapter, the design of a typical light-framed home is discussed. 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. All organic materials should be removed along with excessive amounts of water. Connectors for the truss ends must be able to simultaneously transfer uplift and north-south shear loading as well as shear loading alone in the east-west direction. It is possible to use 24 studs spaced at 406.4mm (16inch) O.C., but this is not common because of the popularity of using fiberglass batts to meet the International Energy Conservation Code (IECC) [7] envelope insulation requirements. By Cecilia Mark-Herbert, Elin Kvennefeldt and Anders Roos. The second floor has four bedrooms with the master suite containing its own large bathroom as well as a sitting area and walk-in closet (WIC). The majority of the connections in a typical home can be found in IRC Table R602.3. The top and bottom plates serve to transfer both gravity and lateral loads between floors. By minimizing the amount of different beam sizes on the plan, the designer reduces the risk of misplacement of headers. Some guidance is typically specified in the manufacturer literature. Brief introduction to this section that descibes Open Access especially from an IntechOpen perspective, Want to get in touch? 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. As in the case of roof sheathing, floor sheathing serves two purposes. This allows for some additional safety precaution when plain concrete footings are used. The scope is limited to the structural design and performance of one single-family residential dwelling. The following components are found in the wall frame: Traditional roof frames distribute roof loads across the building to load bearing walls. Pattern loads are considered in the structural analysis software package Enercalc that was used for beam design. The main serviceability criterion considered in the design of residential homes is deflection. Figure 7 shows the moment diagram for the controlling load combination and the spans that were loaded to produce it. Typical I-joist and LVL (courtesy Timber Rock Homes). It also acts to enclose the perimeter of the floor system. Framing lumber is easily obtained in most locations. The 26 designation refers to a wood framing member with a nominal 50.8mm (2inch) width and a 152.4mm (6inch) depth. The result of specifying and detailing typical structural elements of the home will be specified and details provided. The IRC is the prevailing design code used for the construction of one- or two-family dwellings in the USA. Excessive interior floor deflections are generally noticed in the form of floor vibration or spongy floors. The load path will be discussed as well as specific design codes relating to wood-framed structures. Results were within 1% of each other between the two analysis packages. The connections between the studs and the plates are according to IRC Table 603.2(1). Light-wood framing construction techniques have been traditionally used in America for the construction of single-family residences. Typically, the gravity loads govern the thickness choice of subflooring, and the shear requirements dictate connection to joists [8]. Figure 8 shows an example of typical adjustable columns. This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Live loading is a gravity loading that is temporary or intermittent in nature. Another consideration for girder sizing is live load pattern loading. 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. Limit floor beam deflection to 12.7mm (inch). Holes in dimensional lumber typically require structural analysis and stress evaluation as they become large relative to the depth of the joist or beam. The unit pieces of dimensional lumber are light and easily handled once on the work site. Simplified design wind pressure (Ps) case B =0. In addition to the external loads, the serviceability criteria must also be considered. 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. This connection resists both shear and uplift. This reduced the demand/capacity ratio to the acceptable level of 0.698. The design professional will typically use these design aids to the greatest extent possible and then perform structural analysis and design for any item that is beyond the scope of the design aids. ACI 332 Section 6.2.4.1 prescribes the use of two 12.7mm diameter (inch) bars for locations with discontinuities less than 914.4mm (36inch) in length. Limit I-joist deflection ratio to length/480. Chapter 28 requires that the structure meets the definition of a low-rise, enclosed simple diaphragm building that is regular-shaped in accordance with Section 26.2. The diaphragm is treated like a deep beam for the purposes of analysis. 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. (a) Typical basement wall and (b) typical garage frost wall. This is often costlier than the extra amount of sheathing required for the WSP method. Wood framing, or light frame construction, is the assembly of dimensional lumber or engineered wood lumber that is regularly spaced and fastened together with nails to create floor, wall and roof assemblies. Wood is the most common material used within the construction industry today. The garage can sometimes help resist main building wind loading as long as the wall offsets are not too large; otherwise they must be treated completely separately as far as wall bracing goes. The load effects created by the external wind forces were used to specify the hold-downs and shear connectors necessary to maintain continuity of MWFRS load path. The first floor contains a large kitchen open to the family room with access to both the dining room and the attached two-car garage. No vertical reinforcing is necessary, but horizontal reinforcing is still required (Figure 9b). Video by Illusion Productions shows a Sundance Home being framed from foundation to roof. Metal hardware such as that made by USP [10] or Simpson Strong Tie [11] is used to make any flush beam-to-beam or joist-to-beam connections within the floor system. In this chapter, the complete process of designing a typical US residential dwelling using wood-frame systems will be illustrated. This will provide a fairly accurate estimate and allow the designer to select a floor assembly depth. Home > Books > Timber Buildings and Sustainability, Submitted: September 19th, 2018 Reviewed: March 18th, 2019 Published: May 11th, 2019, Total Chapter Downloads on intechopen.com. The wall region beneath the supporting columns for the garage door header controlled the design. When specifying headers, the designer may choose to specify larger headers in some locations for consistency sake. In this example, the wall footing design is split into three segments, the main load-bearing walls of the east and west (perpendicular to joist and truss spans), the gable end walls, and the garage walls. First, it acts in the gravity system to distribute floor loads to the joists. Moment diagram showing maximum internal moment over support 2. 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. It is important to recognize that the ground must be properly prepared and evaluated to ensure good load transfer. A designer or architect will typically draw the shape of the roof system, and then the truss designer will design the truss system to fit the concept. Wind is transferred from a tributary area of the exterior wall to the rim board of the floor assembly and then into the structural sheathing. In addition, this is a readily available steel section from the builders steel supplier. Excessive deflections can cause problems for the occupants and potentially damage to nonstructural components such as cladding or fenestration. According to IRC Table R503.2.1.1(1), 11.1mm (7/16inch) roof sheathing (24/16 span rating) is acceptable for this example. Also restraint against rotation should be provided at the ends of the beams, which are seated in the beam pockets. 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. As shown in Figure 4, I-joists have become popular and cost-effective in the residential home construction market. Design the home using a wood-framed platform system. Wood structural materials are preferred by US homebuilders largely because (1) the US home building industry is mostly familiar with wood framing method, (2) the units of construction (i.e., studs, joists, panels, etc.) Wall footings were designed as plain concrete strip footings according to the requirements of ACI 318, considering the increased modulus of rupture allowed by ACI 332 Chapter 7. Based on soil categorization, the ACI provides prescriptive foundation sizing tables in Appendix A of ACI 332, which are usually appropriate for most situations. The length of I-joists is generally only limited by transportation and site restrictions. Negative moment occurs at the intermediate supports, which puts the bottom flanges in compression in those regions. Small sizes tend to have stability issues and can be susceptible to local buckling problems caused by larger point loads. IRC Section R602.10 will be used to specify shear panel length and location along the wall line. Double joists often require padding at connections and sometimes bearing, which is usually OSB, to compensate for the space between the web and flanges. This is the approach that is taken for this study. Both allowable stress design (ASD) and load resistance and factor design (LRFD) load combinations will be utilized for different aspects of the home structural design. The floor plan has features typically seen in modern homes. 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. around sheathing edges and 304.8mm (12inch) O.C. (c) An example of a segmental shear wall load distribution approach. The truss end loads are, respectively, 0.18kN (40lbf) and 0.27kN (60lbf). Rafter framing is accomplished in the same manner as platform framing. Enercalc runs all permutations of live load application and reports the worst-case scenario in envelope format. For the example case presented here, however, a set of detailed truss drawings are not available. The roof sheathing also transfers the lateral wind loading through diaphragm action to the structure. When this occurs and the designer is using the continuously sheathed wood structural panel (CS-WSP) method, Section 602.10.4.4 requires the use of 3.56kN (800lbf) hold-down devices in lieu of a 2 foot corner return. 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. The floor assembly deflects, which causes tension and compression forces called chord forces in the walls below, which are perpendicular to the wind loading. Typically, it is the responsibility of the home designer to ensure that the gravity and lateral loads from the trusses are properly transferred to the wall below. This creates the opportunity for twisting. This will decrease the chances of misplacing columns. In this study, only a few of the typical critical connections for the structural system were specified. If only the full intensity live load application was to be considered, then the design moment would have been underestimated by approximately 5%, and the support reactions would have been underestimated by approximately 5% at supports 2, 4, and 12% at support 3. A W8x18 girder works well for them because its a shallow beam and the flange width is small enough that the beam can fit in a 26 wall making the girder unnoticeable if the basement is ever finished. The only lateral load being considered for this study is the wind loading. A combination of components are used to transfer load from the above-grade portion of the home to the ground. Free body diagram of a basement wall. Dimensional wood lumber is readily available and due to its convenient unit dimension can be packaged neatly and transported to work sites by either commercial transport or personal vehicle. Stair frames create the openings which allow for pedestrian travel from floor to floor. The stair frame carries active loads to outside walls or to vertical studs that support the stair frame. 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. D+0.75L+0.75(0.6W)+0.75(Lr or S or R). 2019 The Author(s). In this case, the sheathing will serve as both the underlayment and the subflooring. 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. Contact our London head office or media team here. Approaches for the designs will be discussed as appropriate. The associated detailed calculation is not provided due to space limitation; only the necessary results will be mentioned. Simplified design wind pressure (Ps) case A =30. An example of a typical truss connector is shown in Figure 12. Typically, a designer will send their floor plan along with preliminary input from the designer to the I-joist manufacturer. Once again IRC Table R503.2.1.1(1) will be used to size the sheathing. The gable end wall footings and garage footing were able to be reduced to 203.2406.4mm (8inch by 16inch). An example is when joist bays are used for heating, ventilating, and air conditioning (HVAC) ductwork, the joists are often spread in those locations to 609.6mm (24inch). 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. The floor plan was provided by S&A Homes, which is a midsized homebuilder that builds homes and provides architectural design services to customers in Pennsylvania and West Virginia. It is common for designers to use span tables to select an initial floor joist size. LVLs are conveniently made in the same depths as I-joists, which makes it easy to use within the floor systems. The footings were designed as plain concrete footings. In the State College area, seismic loading does not typically control the design of structural components. While cladding compatibility, thermal performance or the hygrothermal characteristics of a wall system are very important, such aspects are not the focus of this study and will not be discussed. To date our community has made over 100 million downloads. Residential wall footings are typically specified in depths of 152.4mm (6inch), 203.2mm (8inch), or 254mm (10inch), and widths are generally varied in 50.8mm (2inch), 76.2mm (3inch), or 152.4mm (6inch) increments. Structural wood panels are used on the exterior side of the wood framing, and gypsum wallboard on the interior provides the shear resistance and load transfer capability. These documents are adopted by the 2015 IRC and often lead to more economical designs when compared to the requirements of the IRC. The IRC largely provides a prescriptive basis for home design and in many instances is adequate for single-family home design. The designs will include only the effects of dead loading, floor live loading, roof live loading, snow loading, and wind loading. In the east-west direction, the common north wall between the garage and the main structure is generally treated as an exterior wall, and bracing will be prescriptively specified as such, which will act to transfer load from both the garage and the main building. It is possible that 15.1mm (19/32inch) or 15.9mm (5/8inch) sheathing could be used, but spans are restricted to 508mm (20inch). Then based on application of the resultant loads on typical structural elements, detailed designs for roof sheathing, roof trusses, exterior walls, main wind force resisting system, floor system, girders, columns, and foundation walls and footings were presented and discussed. For example, a two-ply 28 beam, with a demand capacity ratio of 0.944 controlled by bearing, is adequate for BM3, but because the entire back wall on the first floor is composed of two-ply 210 headers and all the other headers in the building are 26s, it makes sense just to specify a two-ply 210 beam for this location as well. When using a wood truss system as part of the roof diaphragm, such as the one in this home design example, structural connectors are typically specified to transfer the horizontal shear loads and uplift loads resulting from the roof wind loading. The improved stability and increased stiffness of I-joists allow designers to consider larger spacing for the floor joists. Secondly, it is the primary shear resisting component in the floor diaphragm, which will be discussed subsequently. 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. Attics defined as the unfinished area between the roof and the ceiling of the floor below. 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. As PhD students, we found it difficult to access the research we needed, so we decided to create a new Open Access publisher that levels the playing field for scientists across the world. Licensee IntechOpen. This almost eliminates the need for bridging in a floor system and ensures consistency of engineering properties. The floor sheathing then transfers that load to the exterior shear walls (structural panels within the wall system) parallel to the wind direction below the floor assembly. The gravity loads are those loads that act in the direction of gravity. The gravity loads of importance for residential structures are dead load (DL), floor live load (LL), roof live load (RL), and snow load (SL). Additionally, lumber joists are only available in certain lengths. The magnitudes of the loads were reported previously in Tables 6 and 7. (d) Shear wall segment resolution of overturning forces. or a keyway to be provided in this instance since unbalanced backfill height exceeds 1.22m (4foot). Our team is growing all the time, so were always on the lookout for smart people who want to help us reshape the world of scientific publishing. The IRC prescribes the maximum allowable deflection of structural members and assemblies. Considering ASD load combination 4 and a point load distribution angle of 45 degrees within the concrete wall, the soil pressure beneath the column would be approximately 67kN/m2 (1400lbf/ft2) as well. The following list identifies and describes each component within each type of assembly. Typically, there are sufficient nails engaged to resist the shear force. Engineered wood lumber products are manufactured structural components engineered to meet specific design requirements. The three live loads considered for the design of this home are floor live (LL), roof live (RL), and snow load (SL). 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]. The structure was checked for overturning at the second floor and at the first floor. It is common to specify I-joists at 487.7mm (19.2inch) O.C., whereas it was generally common in the past to specify dimensional lumber joists at 406.4mm (16inch). The advantage of this is that when using a double 26 top plate, the joists or trusses that bear on the wall do not have to bear directly on the stud. No soil testing data is available, so the IRC minimum of 71.8kN/m2 (1500lbf/ft2) prescribed in Table R401.4.1 will be used for design. Section R602.10 has provisions for various wall bracing methods. These loads are typical for residential design and were largely derived from ASCE 7 Table C3-1. If engineered design is necessary in conjunction with the prescriptive standards, then compliance with the 2015 International Building Code (IBC) [3] requirements for those portions of the design is required. Weight is derived from Weyerhaeuser publication #TJ-4000 for 230 or 360 series joists. An I-joist package will typically arrive at the site precut and ready to be installed with minimal modification. The procedures in ASCE 7 will be used to determine wind loading, e.g., Chapter 28 Envelope Procedure Part 2 can be used for this structure. ; however, it is more typical for the studs to be spaced at 406.4mm (16inch) O.C. External loading for homes is prescribed in either Chapter 3 of the 2015 IRC or in ASCE 7. The process of load selection and load path and load combination was discussed. SCM Section J10.7 requires all unframed girder ends to have a pair of transverse stiffeners if unrestrained. 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. Many times, homes have attached garages where the garage is not integral to the main living space, such as the one in this example. Typically, the panels are specified by design aids such as the IRC or the Wood Frame Construction Manual (WFCM). Vertical loads must have a continuous path to the ground. It is common practice in residential design to specify the foundation walls prescriptively but design the footings. If ignored, this could have led to the undersizing of both adjustable column and pad footing. The wall footings will be designed (as opposed to prescriptive). It is common for designers to use either steel girders or manufactured lumber girders in homes today. The items specified from the IRC in this wood-framed section are based on compliance with this table. The main structural assemblies are described and subsequently designed using a combination of prescriptive guidance and engineering design. Plywood or OSB is typically used for the wood structural panels. for intermediate field spacing. The garage was not analyzed, but the procedure would be the same. Applied on the horizontal projection rather than along the slope. As shown in Figure 11a, wind load is transferred from exterior walls perpendicular to the wind direction to structural wood panels, typically OSB or plywood, attached to roof or floor framing. At least one of the corners does not meet this criterion. 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. ASCE 7-10 Chapter 28 wind loading designation (with permission from the ASCE). In this home, concrete walls supported by concrete strip footings are used to support the exterior walls and resist lateral earth pressure. An I-joist floor system is an engineered product. This chapter presented a complete design of a typical US single-family home made of conventional wood-frame system. Continuous strip footings will be used to support the exterior foundation walls. Open Access is an initiative that aims to make scientific research freely available to all. A portion of Table R301.7 from the IRC that prescribes residential deflection limits is reproduced below in Table 8. The typical US design methodology and basis will be used to accomplish the designs. For this design, the equivalent soil pressure will be estimated at 2.15kn/m2 per linear meter (45lbf/ft2 per linear foot). In this home design, an engineered floor system will be used. We are a community of more than 103,000 authors and editors from 3,291 institutions spanning 160 countries, including Nobel Prize winners and some of the worlds most-cited researchers. The floor assembly is treated as a flexible diaphragm when transferring lateral loading. Pre-cut lengths of lumber start at 4 feet long and, increasingby 2 foot increments, can be foundup to24 feet long. Interior pad footings are not subjected to weathering, so 17MPa (2500psi) concrete compressive strength is adequate. This is the approach that will be used for this study. The sheathing layout and the attachment of the sheathing to the I-joists have the greatest effect on the strength of the diaphragm. Dead loads are listed in Tables 1, 2, 3. Additionally, if no compression flange bracing is assumed at the supports, then the beam fails the concentrated load check in SCM J10.4 for web sidesway buckling. Some developers are comfortable relying on the unreinforced concrete footing to maintain its integrity over the service life of the building, but some prefer to add light reinforcing to help prevent cracking due to unexpected soil discontinuities. The load-bearing wall systems are the primary components of the building enclosure, and the structural properties of the wall system are only one of many considerations that must be taken into account. IRC Table 602.3(1) specifies attachment of the sheathing to joists with a 50.8mm (2inch) 6D deformed nail or a 63.5mm (2inch) 8D common nails spaced at 152.4mm (6inch) O.C. IRC Table 602.3(3) prescribes a 9.5mm (3/8inch) minimum structural panel thickness for 406.4mm (16inch) O.C. The home design considered in this study is a two-story regular-shaped home with a basement and attached two-car garage. The gravity system transmits the vertical loads through a system of trusses, joists, and beams to foundation, which in turn transmits the load to ground, while the MWFRS transfers lateral wind load to foundation through a system of shear walls and flexible diaphragms. Maintenance Tips: Automatic Sprinkler Systems. The garage wall foundation walls are all 0.91m (3feet) in height and have no unbalanced backfill. An average of zones E and F that was calculated to be 0.95kN/m2 (19.8lbf/ft2) was applied vertically to the windward side of the roof, and an average of zones G and H that was calculated to be 0.61kN/m2 (12.7lbf/ft2) was applied vertically on the leeward side of the roof.