Farm Structures PDF - Agricultural Engineering Board Review Materials

Agricultural Engineering Board Review Materials Farm Structures Prepared by Ronaldo B. Saludes Assistant Professor I Agrometeorology and Farm Structures Division Institute of Agricultural Engineering...

Agricultural Engineering Board Review Materials Farm Structures Prepared by Ronaldo B. Saludes Assistant Professor I Agrometeorology and Farm Structures Division Institute of Agricultural Engineering College of Engineering and Agro-Industrial Technology University of the Philippines at Los Baños College, Laguna May 2009 (Reproduction with Permission Only) PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 1 Farm Structures Ronaldo B. Saludes Assistant Professor I Agrometeorology and Farm Structures Division Institute of Agricultural Engineering College of Engineering and Agro-Industrial Technology University of the Philippines at Los Baños College, Laguna I. Introduction  Farm buildings and structures are important parts of an integrated rural development.  Knowledge on the design and construction of farm buildings are needed to have an effective storage, especially for the new high yielding grain varieties which are more susceptible to pests than the traditional types  Improved management and breeding programmes to increase animal production have created a need for more appropriate animal housing.  To improve the standards of living for the rural population, it is necessary to provide durable, comfortable and healthy homes, with clean water, sanitation facilities and community infrastructure. II. Topics on Structures TYPES OF FARM STRUCTURES A. Farm Houses E. Food and Crop Processing Buildings B. Livestock Buildings  Milk houses  Barns (beef cattle, dairy, horse, etc.)  Slaughter houses  Hog houses  Grain driers  Poultry houses  Pasteurizing and bottling plants C. Product Storage Buildings  Fruit and vegetable washing,  Granaries dehydration, and packing  Silos F. Equipment and Supplies Building  Vegetable storages  Garages  Fruit storages  Farm shops  Bins  Utility D. Crop Production buildings G. Miscellaneous Structures  Greenhouses  Fences  manure pits BASIC STRUCTURAL ELEMENTS 1. Tension members  slender structural members subjected to tensile stress (e.g. tie rods, hangers) 2. Beams  structural member subjected to loads perpendicular to the long axis of the member  normally in horizontal position (e.g. floor joists, girders) but sometimes found in an inclined and vertical position (e.g. rafters in roof and studs) 3. Compression members  vertical members that resist axial compressive loads (e.g. columns) Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 2 4. Combined members  members subjected to combined effects of compression/tension and bending (e.g. beam columns) P P P (a) tension member (b) beam P P P P (c) column (d) beam column FUNDAMENTAL CONCEPTS OF STRESS ANALYSIS STRESS – internal resistance to an external force Basic Stress Formula: where P  unit stress (Pa) = ------- P external force (N) A A cross sectional area (m2) Assumptions  Stress is uniformly distributed over the area  Load is axial or perpendicular to the area THREE BASIC KINDS OF STRESS a. Compression – results from a force that tends to compress or crush a member b. Tension – results from a force that tends to stretch or elongate a member c. Shear – results from the tendency of two equal and parallel forces, acting in opposite directions, to cause adjoining surfaces of a member to slide one on the other. Types of Shear P Horizontal shear (slides horizontally) Vertical shear (dropping down between supports) Note: Horizontal shear failure on wood beams is very common because the shearing resistance of wood is much less parallel to the grain than that of across the grain. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 3 MATERIALS OF CONSTRUCTION A. WOOD  one of the most common construction materials Qualities  strong material  light in weight  durable  with artistic and natural beauty  ease of fastening Lumber Measurement  wood is normally priced in board foot (fbm)  one board foot of wood has a nominal size of one foot length by one foot width by one inch thick Board foot formula where: L x W x t fbm = board foot fbm = 12 L = length, feet W = width, inches t = thickness, inches Note:  thickness and width of commercially available lumber is in inches while length is in feet of even length  nominal sizes of 2”x 2” and lower are priced based on linear foot and not by board foot RECOMMENDED END-USES OF PHILIPPINE TIMBER STRENGTH GROUP END USES Heavy-duty construction where both strength and Class I durability are required such as bridge, girders, rafters, (High Strength) chords, purlins, balustrades, stairs, high-grade beams Medium-heavy construction such as heavy duty furniture, CLASS II cabinets, door panels and frames, tool handles, plywood, (Moderately High Strength) beams, girders, rafters, chords, purlins Medium construction such as general framing, paneling, medium-grade furniture, cabinet, , low-grade beams, CLASS III girders, rafters, chords and purlins, drafting tables, dry (Medium Strength) measures Production of pulp paper, woodcarving and sculpture, toys, crates, pallets, conventional furniture, form wood, CLASS IV shingles and matchwoods (Moderately Low Strength) Light construction where strength, hardness and durability are not critical requirements such as mouldings, ceiling CLASS V and acoustic panels, pulp and paper making, wall boards, (Low Strength) pencil slats, matchsticks, popsicle sticks Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 4 Plywood  made up of 3,5,7 or more veneer slices laid one upon the other with grain of each at right angles to those of the sheets above and below it  thickness varies from 3.2 mm, 4.7 mm, 12 mm, 20 mm with a width of 1.20 m and length of 1.80 m to 2.40 m Types of plywood a. Softwood – most common for structural use b. Hardwood – used for paneling and finishing where usually only one face is with hardwood finish c. Marine – for external use B. CONCRETE  a solid, hard material produced by combining cement, fine aggregates, coarse aggregates and water  used commonly in farm buildings for footings, foundation walls, floors and pavements, silos etc. Qualities a. durability c. strength in compression b. hardness d. ease of forming into various shapes Paste – mixture and cement and water Mortar – mixture of cement, water and sand Grout – specially formulated mortar Functions of Mortar a. used to bond units together b. seal the spaces between the units c. tie steel reinforcement and anchor bolts into the wall d. provide design of lines of color and shadows CONCRETE PROPORTIONING  FULLER’S FORMULA Let C = no. of bags of cement per cubic meter of concrete work S = volume of sand (m3) per cubic meter of concrete work G = volume of gravel (m3) per cubic meter of concrete work c , s , g = cement-sand-gravel ratio (relative amounts of solids by volume in a mixture) C = 55 / ( c + s + g) S = 0.028 * C * s G = 0.028 * C * g Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 5 Class A (1:2:4) - used for beams, slab columns, and for all members which are subjected to bending stress Class B (1:2.5:5) - used for all members not reinforced for bending stress Class C (1:3:6) - used for footing not under water Type of construction Proportion Side Walk 4” thick 1:2:4 Floor Slab 4” thick 1:2:4 Wall 1:2.5:5 Footing 1:2.5:5 Post 1:2.5:5 Machinery Foundation 1:3:6 Reinforced Concrete 1:2:4 Foundations 1:2.5:5 C. MASONRY Concrete Hollow Blocks (CHB)  most widely used masonry material for all types of construction walls, partitions, dividers, fences, etc. Classification a. Bearing – thickness ranges from 15 cm to 20 cm and are used to carry load aside from its own weight b. Non-bearing – thickness ranges from 7.5 cm to 10 cm and are intended for walls, fences 20 cm Concrete hollow block 40 cm Items to estimate for a concrete hollow block work  quantity of CHB (12.5 pcs/m2 of work)  quantity of cement and sand for block laying  quantity of cement, sand and gravel for filling cells  quantity of cement and fine sand for plastering  quantity of cement, sand, and gravel for CHB footings Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 6 D. ROOFING MATERIAL Galvanized Iron (G.I.) Sheet  most common and widely used roofing material Qualities  Reasonable cost  Availablitiy  Durability  Ease of installation and repair Standard commercial forms 1. Plain  widely used for roofing, gutter, flashing, ridge etc.  standard size of 90 cm wide by 2.4 m long 2. Corrugated  widely used for roofing and siding material  standard width of 80 cm with varying length of 1.5 m to 3.6 m at an interval of 30 cm Corrugated G.I Sheet Thickness  measured in terms of gauge number ranging from no. 14 to no. 30 ( higher gauge no., the thinner the GI sheet) Lapping of roof sheet a. Side lapping  1 ½ corrugations – has an effective width covering of 70 cm  2 ½ corrugations – has an effective width covering of 60 cm b. End lapping – ranges from 20 cm to 30 cm depending on the degree of slope and number of sheet in the longitudinal row 20 – 30 cm Purlin End lapping Side Lapping Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 7 Steps in estimating corrugated G.I sheets 1. verify specifications for side lapping and end lapping 2. minimize the end lapping joint of sheet and always choose longer length for economical reasons 3. know the length of purlin 4. compute the no. of sheets per row by dividing the purlin length with the effective width covering per sheet 5. know the length of rafter/ top chord and choose the right combination of sheets to satisfy the length 6. solve for the total no. of sheets needed for roofing ESTIMATING STRUCTURAL LOADS Classification of loads based on the area over which they are applied a. Concentrated load – load applied at a point or along a line b. Distributed load – load spread over a large area c. Uniformly distributed load – load is equal over all portion of the contact area Two major types of loads in building design A. Vertical loads 1. Dead loads  include the weights of various structural members and materials permanently attached to the structure (e.g. weight of roofing or floor covering, columns, beams, girders, walls, windows, etc.)  estimated dead load of wood beams (uniformly distributed) 10 ft span = 2 % of total load 20 ft span = 10 % of total load  estimated dead load of roof trusses (wood) W = ½ SL(1+0.1L) (Merriman’s formula) where W weight of one truss, lbs S bay (distance between adjacent trusses), ft L span of truss, ft 2. Live loads  gravity loads which are not permanently applied to the structure i. roof live loads – include loads imposed during building construction (e.g. roofing process) and after construction (e.g. re-roofing operations, air conditioning and mechanical equipment installation and servicing) ii. floor live loads –based on the occupancy or use of the building (human occupants, furniture, stored materials, etc.) B. Lateral loads  include wind loads and seismic loads Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 8 WIND LOADS  occurs when structures block the flow of wind converting wind’s kinetic energy into potential energy of pressure. Design wind pressure for buildings Basic formula p = Ce Cq qs I where p design wind pressure Ce combined height, exposure, and gust factor coefficient Cq pressure coefficient qs wind stagnation pressure I importance factor Methods of determining wind loads for primary lateral-force- resisting system (LFRS) a. Normal Force Method  gives more accurate description of wind forces  used for buildings with gable rigid frames b. Projected Area Method  simple and produces satisfactory design for most structures  not applicable to gable rigid frames or to structures greater than 200 ft in height wind ward wind ward leeward leeward 0-5 m NORMAL FORCE PROJECTED AREA METHOD METHOD Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 9 Loads on Suspended Floors kN/ m² Cattle Tie stalls 3.4 Loose housing 3.9 Young stock (180 kg) 2.5 Sheep 1.5 Horses 4.9 Pigs (90 kg) Slatted floor 2.5 (180 kg) Slatted floor 3.2 Poultry Deep litter 1.9 Cages Variable Repair shop (allowance) 3.5 Machinery storage 8 (allowance) Mass of Farm Products Product Mass kg/m³ Maize, shelled 720 Maize, ear 450 Wheat 770 Rice (paddy) 577 Soybeans 770 Dry beans 770 Potatoes 770 Silage 480-640 Groundnuts, unshelled 218 Hay, loose 65-80 balled 190-240 NAILED CONNECTIONS Classification of nails with respect to service a. Common nails b. Flooring nails c. Finishing nails d. Roofing nails e. Boat, etc. Factors affecting strength of nailed connections 1. number, size and type of nail 6. condition of use (MC) 2. species of lumber 7. duration of load 3. nail penetration 8. type of sideplate 4. type of connection 9. spacing of nails 5. direction of nailing Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 10 Members in a Nailed Connection nail side s member holding member Nail penetration Types of nailed connection A. Laterally Loaded Connections  Load is applied perpendicular to the length of nail  Most common nailed connections Two types of laterally loaded connections a. Lateral resistance in side grain – nail is driven perpendicular to the grain of holding member. nails side member holding P member P  strongest type of nailed connection b. Lateral resistance in end grain – nail is driven parallel to the grain of holding member side member nail P P holding member The allowable design load for common nails and spikes driven into the side grain of seasoned wood can be calculated using the formula: P = KD1.5 Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 11 where P allowable lateral load in pounds per nail at rated penetration K a constant related to the density of the wood D diameter of the nail Rated penetration of wood species grouped according to density and other mechanical properties: Group I 10 nail diameters Group II 11 nail diameters Group III 13 nail diameters Group IV 14 nail diameters For actual nail penetrations less than the rated values, the reduced allowable lateral load is in proportion of the actual penetration to the rated penetration. No increase is allowed for penetrations above the rated values. Allowable lateral loads for nails driven into the end grain of wood are 2/3 those of side grain. B. Withdrawal-Type Connections  Load is applied parallel to the length of nail  Load attempts to pull the nail out of the holding member  Weaker and less desirable than connections subjected to lateral load Two types of withdrawal-type connection 1. Withdrawal from side grain – nail driven perpendicular to grain of holding member P/2 P/2 P holding member nail side member 2. Withdrawal from end grain – nail driven parallel to grain of holding member nail side member P/2 P/2 holding member P Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 12  inherently weak connection and is not permitted in the design (no allowable load) Allowable withdrawal load for common wire nails and spikes driven into the side grain of seasoned wood that will remain seasoned, or unseasoned wood that remained unseasoned in service can be calculated from the formula: P = 1380 G2.5D where G specific gravity of wood based on oven dry weight and volume D nail diameter in inces P Allowable load in pounds per inch of penetration The allowable withdrawal load for common wire nails driven into end grain is only one half that obtained in side grain. DESIGN OF RECTANGULAR WOOD BEAMS a. BENDING STRESS Design Formula b = M / S <  ’b where b actual bending stress ’ b allowable bending stress M maximum bending moment of beam S section modulus of beam b. HORIZONTAL SHEAR STRESS Design Formula V = 3/2(V/A) < ’V where V maximum horizontal shearing stress V’ maximum horizontal shearing stress V maximum design shear in the beam A cross sectional area of the beam Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 13 c. DEFLECTION  deformation that accompanies bending  maximum deflection occurs at center span for simple beams maximum deflection max Design formula max < allowable  Deflection formulas for simple beams a. Uniformly distributed load max = (5/384) x (wl4)/(EI) b. Concentrated loads  beam carrying single concentrated load at the center span max = 1/48 x (Pl3)/(EI)  beam carrying two equal concentrated loads located at the third points of span length max = 23/648 x (Pl3)/(EI) where max maximum deflection of beam, m w uniformly distributed load, N/m P concentrated load, N l span length, m E modulus of elasticity of wood, N/m2 I moment of inertia of beam section, m4 Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 14 Maximum Allowable Deflection for Structural Members Type of Member Member loaded with live load Member loaded with live only load and dead load Roof Member Supporting L / 360 L / 240 Plaster or Floor Member d. BEARING STRESS  compressive stress perpendicular to grain of wood occurring at beam supports or other members framed into the beam P1 Column beam c c beam support P2 Design Formula C = P/A < ’C where C actual bearing stress ( to grain of wood) ’c allowable bearing stress (compressive stress perpendicular to grain) P reaction force A contact (bearing) area between beam and support DESIGN OF SIMPLE SOLID WOOD COLUMN Simple Solid Column – consists of a single piece of wood, square or rectangular in cross section Design Formula c  = P / A < ’c  Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 15 where c  actual compressive stress parallel to grain of wood ’c  allowable compressive stress parallel to grain, adjusted based on slenderness (l/d) ratio P axial compressive load A cross-sectional area of column (either gross or net area) General Slenderness Ratio (SR) SR = le / r where SR slenderness ratio le effective unbraced length of column r least radius of gyration of column cross section For rectangular columns SR = le / d where d least cross sectional dimension of the column Classification of solid columns based on slenderness ratio a. SHORT COLUMN SR < 11 b. INTERMEDIATE COLUMN 11 < SR < k k = 0.671 (E / ’’C )1/2 where E modulus of elasticity of wood ’’ C  tabulated allowable compressive stress parallel to grain c. LONG COLUMN k < SR < 50 Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 16 Adjusted allowable compressive stress parallel to grain based on column classification SHORT COLUMNS ’C  = ’’C  INTERMEDIATE COLUMNS ’C  = ’’C  [ 1 – 1/3 (SR / k )4 ] LONG COLUMNS ’C  = 0.30 E / (SR)2 where ’C  adjusted allowable compressive stress based on column classification ’’C  tabulated allowable compressive stress parallel to grain DESIGN OF AXIAL TENSION MEMBER Design Formula t = P / An < ’t where t actual tensile stress ’t allowable tensile stress P axial tensile load An net cross-sectional area of member (gross cross-sectional area of member minus projected area of any bolt holes) DESIGN OF COMBINED STRESS MEMBER Combined Stress Member  member subjected to bending and axial forces (tension or compression) simultaneously Combined Bending and Axial Tension Interaction Formula (t / ’t) + (b / ’b) < 1.0 where t actual tensile stress ’t allowable tensile stress b actual bending stress ’b allowable bending stress Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 17 Combined Bending and Axial Compression Interaction Formula [C  / ’C ] + [(b / ’b) – J C ] < 1.0 where c  actual compressive stress parallel to grain ’c  adjusted allowable compressive stress parallel to grain b actual bending stress ’b allowable bending stress J modifier for the P- effect J=0 for short columns J = (SR – 11) / (k – 11) for intermediate columns J = 1.0 for long columns DESIGN OF REINFORCED CONCRETE BEAM Working Stress Design b fc kd/3 kd C jd h d As = pbd T fs/n the reinforced distribution of section bending stress Moment resistance of a rectangular concrete section with tension reinforcing Notations and Symbols b width of the concrete compression zone d effective depth of the section for stress analysis; from centroid of steel bars to the edge of compression zone As cross-sectional area of the reinforcing steel bars p percentage of reinforcing ( p = As/bd) n elastic ratio (Esteel / Econcrete) kd height of compression stress zone; percentage k of d jd internal moment arm between net tension force T and net compression force C, percentage j of d fc maximum compressive stress in concrete fs tensile stress in reinforcing steel bars Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 18 The compression force C may be expressed as C = ½(kd)(b)(fc) = ½ kfcbd Using the compression force C, the moment resistance of the section may be expressed as M = Cjd = (½ k fc bd)(jd) = ½ kj fc bd2 This may be used to derive an expression for the concrete stress: fc = (2 M) / (k j b d2) The resisting moment may also be expressed in terms of the steel and the steel stress as M = T jd = As fs jd This may be used for the determination of the steel stress or finding the required area of steel fs = M / (As jd) As = M / (fs jd) Balanced Design A design for reinforced concrete beam that will cause the limiting stresses in the concrete and steel bars to be reached simultaneously, causing them to fail at the same time. balanced k = 1 / (1 + fs / n fc ) j = 1 - k/3 p = (fc k) / (2 fs) Under Reinforced Design A design in which the steel reinforcement is lesser than what is required for a balanced design. It causes the steel bars to reach its limiting stress first while the concrete remains under stressed. Once ultimate load is reached, large cracks become visible in the tensile zone of concrete and will give warning to the occupants to decrease the load. Over Reinforced Design A design in which steel reinforcement is more than what is required for a balanced design. When the ultimate load is reached, the compression zone of the concrete is highly stressed leaving the steel bars under stressed and failure occurs suddenly without warning to the occupants of the structure. The code limits the tensile steel percentage to 0.75 that of balanced design to ensure under reinforced design of concrete beams. This condition will provide ductile type of failure and will give warning to the user of the structure before failure occurs. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 19 STRUCTURAL FRAMES Types of Structural frames commonly found in farm buildings: 1. Beam and post Combining posts or columns and beams having no tension members as in bridge beam and abutment. Here, the compression member (abutment) is a special type of column that also serves as the retaining wall. This type of framing is suitable for multistory poultry houses and other types of dwellings. The essential beams and post members may have to be supplemented with diagonal bracing members. Where low construction cost is important, a variation known as the pole frame is used. In it the concrete pedestal is omitted and the post or "pole” is extended directly into the ground. 2. Truss A truss is a jointed frame that is used to support loads over a relatively long span. In general, the loads are applied to the truss in a direction transverse to its length and the loads are applied only at the joints. Purlin Ridge Roofing Top chord Panel Rise Eave overhang Web members Bottom chord Span Parts of the truss: a. chords are the outer truss members b. web members (diagonals and verticals) are the interior members c. joints or panel points are the joints where members of the truss meet d. bays are the spaces between trusses e. purlins are beams spanning from truss to truss that transmits to the trusses the roof loads f. panels are portion of the truss that occurs between two adjacent joints of the top chord Pitch = rise / span Slope = rise/ (span)/2 = 2 pitch Types of trusses a. Howe c. Pratt e. Warren b. Fink d. Shawver f. braced-rafter 3. Arch This type is used where high rise and floor spaces free of obstruction are desired. Its more frequent use on frames is to provide large hay-storage space over dairy stables and storage space in machinery sheds and similar structures. In two-story construction, the arch may be supported on the wall plate at the second floor level, or it may be continuous from crown to foundation wall with the arch ribs serving as studding in the sidewalls. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 20 4. Rigid Frame This is widely used in bridge construction and industrial buildings. The distinguishing characteristics of the rigid frame are: a. The joints are fixed, or rigid, rather than hinged b. The basic geometric figure is not necessarily a triangle but can be almost any shape c. Some or all of the members carry both bending and axial loads 5. Cylindrical tanks This is especially adaptable to structures in which the walls are subjected to outward lateral pressure due to contained liquid or semi-liquid material. The silo, water tanks and the circular grain bin are the common examples. 6. Light timber framing This framing is the type widely used in the construction of dwellings and other small buildings having a short roof span. The types of light timber frames: a. balloon frame b. platform frame BASIC UNITS OF A FARM BUILDING A. FOUNDATION Foundation is defined as a base upon which a building rests and through which the loads on the building are transmitted to the ground. It is a common practice to place footings under foundation of buildings in order to enlarge the bearing area between the foundation and the ground, thus distributing the load over a larger area and reducing the unit pressure. The combination of foundation and footing keeps the building level and plumb and reduces settling to a minimum. Types of Foundation 1. Continuous wall foundation - may be used either as basement walls or as curtain walls 2. Pier foundation - often used to support the timber frames of light buildings with no suspended floors 3. Pad and pole foundation - consists of small concrete pads poured in the bottom of holes which support pressure treated poles 4. Floating slab or raft foundation - consists of a poured concrete floor in which the outer edges are thickened to 20 to 30cm and reinforced 5. Pier and ground level beam foundation - commonly used where extensive filling has been necessary and the foundation would have to be very deep in order to reach undisturbed soil 6. Piles - are long columns that are driven into soft ground where they support their load by friction with the soil rather than by a firm layer at their lower end Foundation footing design Design Formula Footing area = Total Load / Soil bearing capacity Note: total load = building load + weight of footing Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 21 Soil Bearing Capacities Soil Type kN/m² Massive crystalline bedrock 192 Sedimentary and foliated rock 96 Sandy gravel and/or gravel 96 Sandy, silty sand, clayey sand, silty gravel, and clayey gravel 72 Clay, sandy clay, silty clay, and clayey silt 48 Footing Proportion a a 2a 1½ a Walls and Piers Columns B. WALLS Walls may be divided into two types: a. Load-bearing walls - support loads from floors and roof in addition to their own weight and which resist side pressure from wind and, in some cases, from stored material or objects within the building b. Non-load-bearing walls - carry no floor or roof loads. Each type may be further divided into external or enclosing walls, and internal dividing walls. Good quality walls provide strength and stability, weather resistance, fire resistance, thermal insulation and sound insulation. Types of Building Walls a. Masonry wall - wall is built of individual blocks of materials such as brick, clay or concrete blocks, or stone, usually in horizontal courses bonded together with some form of mortar b. Monolithic wall - wall is built of a material placed in forms during the construction. Examples are traditional earth wall and the modern concrete wall. The earth walls are inexpensive and durable if placed on a good foundation and protected from rain by a rendering or wide roof overhangs. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 22 c. Frame wall - wall is constructed as a frame of relatively small members, usually of timber, at close intervals which together with facing or sheeting on one or both sides form a load-bearing system. d. Membrane wall - wall is constructed as a sandwich of two thin skins or sheets of reinforced plastic, metal, asbestos-cement or other suitable material bonded to a core of foamed plastic to produce a thin wall element of high strength and low weight. Factors which will determine the type of wall to be used a. The materials available at a reasonable cost b. Availability of craftsmen capable of using the materials in the best way c. Climate d. The use of the building - functional requirements In dwelling houses with ceilings, wall height of 2.4m is suitable. Low roofs or ceilings in a house create a depressing atmosphere and tend to make the rooms warmer in hot weather. C. FLOORS For farm buildings, including homes, simple floors offering hard, durable surfaces at ground level grade are probably adequate for the vast majority of situations. Floors may be built at ground level, i.e. on the soil within the building, in which case they are called solid or grade floors, or they may be supported on joists and beams in which case they are called suspended or above-grade floors. The finished level of a solid floor should be at least 150mm above outside ground level as a protection against flooding. The topsoil should be removed and replaced with coarse material before the actual floor slab is constructed. D. ROOFS A roof is an essential part of any building in that it provides the necessary protection from rain, sun, wind, heat and cold. The integrity of the roof is important for the structure of the building itself as well as the occupants and the goods stored within the building. The roof structure must be designed to withstand the dead load imposed by the roofing and framing as well as the forces of wind and in some areas, snow or drifting dust. The roofing must be leak proof, durable and perhaps satisfy other requirements such as being fire resistant, a good thermal insulator or high in thermal capacity. General Roof Shapes commonly used on farm buildings Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 23 Flat Roof – used only to a limited extent on farm buildings. Maintenance is high since the roof has little slope for water to run off Shed Roof – the simplest and easiest to construct and maintain. It is common sight on single story poultry houses, open sheds for cattle or swine, and similar buildings Gable Roof – one of the most universally used roof shapes on farm buildings. This type of roof is commonly seen on two-story poultry houses, dairy barns, and single-story buildings that are too wide for shed type of roof. Hip Roof – more desirable from an architectural standpoint than from utilitarian value. It requires more complicated framing than the gable roof and is consequently more expensive to build. One of the most common uses of hip roof is on garages. Monitor and Semi-Monitor Roof – special types of roof with additional height to give more room for storage. The extension above the main roof was often used for ventilation, and windows in the vertical walls give additional light. Gambrel Roof – used to gain more space for the overhead storage of hay and feed. This roof is common sight on two-story dairy barns and other livestock shelters where overhead storage of hay is desired. Arch Roof – also known as gothic roof. Prefabrication of laminated arched rafters has made the construction of arched roofs simple and easy. Its uses are the same as for the gambrel roof. E. DOORS AND WINDOWS Doors are essential in buildings to provide security and protection from the elements while allowing easy and convenient entry and exit. Farm buildings may be served adequately with unframed board doors, while homes will need more attractive, well-framed designs that close tightly enough to keep out dust and rain and allow only minimal air leakage. Large openings can be better served by rolling doors rather than the side-hinged type. Windows provide light and ventilation in a building an allow those within to view the surrounding landscape and observe the activities in the farmyard. In sitting rooms and workrooms where good light and ventilation are important, the window area should be 5 to 10% of the floor area of the room. Windows sometimes need to be shaded to reduce heat radiation or closed to keep out driven rain or dust. In addition screening may be needed for protection from insects. Shutters, either top-or side hinged, are commonly used to provide the needed protection. Side-hung glazed windows, fly screens and glass or timber louvers are also used. LIVESTOCK HOUSING General Considerations in Planning Livestock Housing  Site and location  Space, feed and water requirement  Suitable environment to maintain highly productive condition  Maximum efficiency of labor condition  Sanitary condition Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 24 A. POULTRY HOUSING The objective in poultry housing is to keep the fowls comfortable, so as to promote health, get maximum production and conserve feed and the energy generated by the birds. A properly designed poultry housing must also aim at removing the excess moisture the birds breathe out from the lungs. If the air in the house is loaded with moisture, serious trouble from disease may develop. Proper ventilation is the remedy for this but poultry houses should be not exposed to strong winds. Draft in poultry houses interferes with the bird's comfort and seriously affects their health. To avoid draft a site is selected where the house will be protected from the prevailing winds thus, ideal windbreak is necessary. Drainage is another important consideration in selecting a site because it causes undesirable dampness. Location near a jungle should be avoided. Light in a poultry house is essential for the well being of the birds. Plenty of sunlight, well distributed through out the house is a good source of their cheerfulness. Floor space required to house hens Bird Size No. of hens in house Floor space per hen, sq m. Small breeds 25 0.37 100 0.32 200 0.28 400 0.25 Large breeds 25 0.42 100 0.37 200 0.33 400 0.30 B. SWINE HOUSING The primary considerations in planning housing for hogs are minimum essential shelter for the animals, arrangement of building and equipment for labor efficiency and sanitation. Hogs can adapt themselves to a wide range of temperatures, although they area not so hardy as other farm animals. For farrowing sows, minimum temperatures of 50° to 60° F are desirable; for your pigs in a cold climate, heated hovers are used. Lower temperature are satisfactory for fattening hogs High temperatures are definitely harmful' above 85° F hogs are susceptible to heat prostration, and in warm climates shade should be provided. Drafts and dampness are considered undesirable. Water consumption and space requirements Animal Type Water Requirements Space Requirements Sow 5 to 8 gal per day 48 to 80 sq. ft Pigs 0.5 to 1.5 gal per day 3 to 6 sq. ft Fattening hogs 1.5 to 3 gal per day 6 to 10 sq. ft Boars 2 to 4 gal per day 20 to 65 sq. ft C. BEEF CATTLE HOUSING Types of floor area for animals with access to outside yards Animal Condition Floor Area (sq. ft) Breeding cow with or without calf 50 Calf Feeders, stockers, and replacement heifers 30 Yearling Feeders, stockers, and replacement heifers 40 Fattening stock Av. 750 lb. for fattening period 45 Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 25 Animal Condition Floor Area (sq. ft) Fattening stock Av.950 lb. for fattening period 50 Bull In pen 120 Cow In maternity pen 100 to 120 Cow In standing stall 4 ft wide, 22 5-6 ft long platform only Calf Several in pen, each 20 Space Requirement Per Animal for an Animal Shelter Type of Animal shelter Floor area (sq.m.) Cow stall plus alleys 6.00 Cow pen 11.10 Calf pen 2.20 Bull pen 16.70 Buffalo pen 13.90 Buffalo stall pus alley 7.40 FARMSTEAD PLANNING The farmstead forms the nucleus of the farm operation where a wide range of farming activities takes place. It normally includes the dwelling, animal shelters, storage structures, equipment shed, workshop and other structures. A carefully organized farmstead plan should provide an arrangement of buildings and facilities that allows adequate space for convenient and efficient operation of all activities, while at the same time protecting the environment from such undesirable effects of odor, dust, noise, flies and heavy traffic. Types of Farmstead 1. Concentrated In this type, all structures are in close proximity, in many instances, will all or most of the buildings joined together or connected by sheds or covered walks. 2. Plantation or Ranch It often consists of two or more separated groups of buildings; one group includes the residence, garage and attendant service buildings; the other group includes barns, storage houses, and principal service buildings and workers' houses. 3. Suburban type It consists primarily of residence and small service buildings, where the essential farm operations area carried on with hired services. 4. Distributed type This is the most common type of farmstead where buildings are located sufficiently far apart to allow adequate room for road drives and yards, reasonable fire safety, and sanitation, yet sufficiently close together to be effective for farm operation. Zone Planning Zone planning can be a useful tool, but it is most effective when planning a new farmstead. The farmstead is divided into different zones of 10 to 30 meters wide by concentric circles as shown below. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 26 1 – Family living area including the dwelling 2 – implement and machinery storage, farm workshop 3 – grain and feed storage 4 – livestock building 5 – farm access road and courtyard Zone I, at the center of the farmstead, is for family living, and should be protected from odor, dust, flies, etc. In Zone II, clean, dry and quiet activities, such as implement sheds and small storage structures can be placed. In Zone III, larger grain storage, feed storage and small animals are placed, whereas large-scale animal production is in Zone IV and beyond. The advantage of zone planning is that it provides space for present farm operations, future expansion and a good living environment. Factors to be considered in Farmstead Planning  Good drainage, both surface and sub-surface, provides a dry farm courtyard and a stable foundation for buildings. A gentle slope across the site facilitates drainage, but a pronounced slope may make it difficult to site larger structures without undertaking extensive earth-moving work  Adequate space should be provided to allow for maneuvering vehicles around the buildings and for future expansion of the farm operation  Air movement is essential for cross ventilation, but excessive wind can damage buildings. Since wind will carry odors and noise, livestock buildings should be placed downwind from the family living area and neighboring homes. Undesirable winds can be diverted and reduced by hedges and trees or fences with open construction  Solar radiation may adversely affect the environment within buildings. An orientation close to an east-west axis is generally recommended in the tropics  An adequate supply of clean water is essential on any farm. When planning buildings for an expanded livestock production, the volume of the water supply must be assessed. Where applicable, the supply pipe in a good building layout will be as short as possible  Similarly, the length of electric, gas and telephone lines should be kept to a minimum  The safety of people and animals from fire and accident hazards should be part of the planning considerations. Children especially, must be protected from the many dangers at a farmstead  It is often desirable to arrange for some privacy in the family living area by screening off the garden, outdoor meeting-resting places, verandah and play area  Measures should be taken for security from theft and vandalism. This includes an arrangement of buildings so that the farm court and the access driveway can be observed at all times, especially from the house  A neat and attractive farmstead is desirable and much can be achieved toward this end, at low cost, if the appearance is considered in the planning, and effective landscaping is utilized. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 27 GLOSSARY OF TERMS Admixture - a material other than portland cement aggregate, or water added to concrete to modify its properties. Age Hardening (precipitation hardening) - occurs in some metals, notably certain stainless steel, aluminum, and copper alloys, at ambient temperature after solution heat treatment, the process being one of a constituent precipitating from solid solution. Aggregate - inert material, which is mixed with portland cement and water to produce concrete. Allowable Stress - it is the maximum unit stress considered desirable for design calculations, considering the characteristics of the material, the type of structure, the degree of exposure to deterioration, etc. Alloy - is a substance with metallic properties composed of two or more elements of which at least one is a metal. Anisotropy - is the characteristics of exhibiting different properties when tested in different directions (as tensile strength "with the grain" or "across the grain) Annealing - is a heating and slow cooling of a solid metal, usually done to soften it. Baluster- a small post supporting the handrail or a coping Balustrade- a series or row of balusters joined by a handrail or a coping as the parapet of a balcony Barn - an enclosed covered building for the keeping and care of livestock and/or storage of roughage. Beam - a structural member that is reasonably long compared with its lateral dimensions when suitably supported, and subjected to transverse forces so applied as to induce bending of the member in an axial plane. Bearing Stress - is a contact pressure between separate bodies. Bending Moment - is the tendency or a measure of tendency, to produce motion, especially around a point or an axis. It is a measure of the stresses acting on the beam. Bridging - process of connecting one joint to another. Brittleness - is the tendency to fracture without appreciable deformation. Building - shelter; a place of equipment that is an aid to the conservation and better use of the farm resources. Centroid - is a point that corresponds to the center of gravity of a very thin homogenous plate of the same area and shape. Charpy Test - is one which a specimen, supported at both ends as a simple beam, is broken by the impact of a falling pendulum. The energy absorbed in breaking the specimen is a measure of the impact strength of the metal. Circular stair- staircase with steps winding in a circle or cylinder Cocktail stair- a winding stair case Cold Shortness - is brittleness of metal at ordinary or low temperature. Cold Working - is the process of deforming a metal plastically at a temperature below the recrystallization temperature and at a rate to produce strain hardening. Column - an element used primarily to support axial compressive loads and with a height at least three times its least lateral dimension. Compressive Stress - tend to press or squeeze an object. Concrete - a mixture of portland cement, fine aggregate, coarse aggregate, and water. Damping Capacity - is the ability of a material to absorb or damp vibrations, which is a process of absorbing kinetic energy of vibration owing to hysterisis. Dead Load - is the weight of the structure itself. Decarburization - is a loss of carbon from the surface of steel occurring during hot rolling, forging, and heat treating, when the surrounding medium reacts with the carbon. Deformation - the amount of change in the materials shape. Ductility - is that property that permits permanent deformation before fracture in tension Durability - materials are considered durable if they retain their strength and other properties over a considerable period of time. Elastic Limit - is the limit of stress within which deformation disappears after the stress is removed Modules - means small measure. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 28 Elasticity - the ability of a material to return to its original shape after the removal of stresses. Embrittlement - involves the loss of ductility because of a physical or chemical change of the material. Factor of Safety - denotes the ratio between the maximum load that a member can carry and the design load; is the ratio of the ultimate strength to the working stress - common factor of safety for wood is 4 and for steel is 2. Farmstead - is a limited area within the farm, occupied by building corrals, fences, and gates, and used generally as center of operations for farm work and activities. Flight of stairs – series of steps leading from one landing to another Floor joist – structural member of a building that carries the wood flooring Form- temporary boarding, sheating or pan used to produce the desired shape and size of concrete Free Carbon - is that part of the carbon content of steel or iron that is in the form of graphite or temper carbon. Girder- structural member of a building that carries the floor joist and the flooring Handrail- a rail running parallel with the inclination of the stairs that holds the balusters Hard Drawn - is a temper produced in a wire, rod, or tube by cold drawing. Hardening - is the heating of certain steel above the transformation range and then quenching, for the purpose of increasing the hardness. Hardness - resistance to indention, usually measured by some form of indention test, is the characteristics of a material most frequently associated with hardness. Heat Treatment - is an operation or combination of operations involving the heating and cooling of metal or an alloy in the solid state for the purpose of altering the properties of the material. Homogenous Materials - have the same structure at all points. (Steel consists of randomly oriented iron crystals of different sizes, with other matter in between and is thus not homogenous). Impulsive Load - a suddenly applied load. Isotropic - materials have the same properties in all directions. (Wood has a grain; rolled steel is not isotropic). Izod Test - is a test which a specimen, support at one end as a cantilever beam, is broken by the impact of falling pendulum. The energy absorbed in breaking the specimen is a measure of the impact strength. Joints - is the entire assemblage at the intersections of the members. Landing – horizontal floor as resting place in a flight Lateral ties – lateral reinforcements of vertical bars in a tied column Live Load - is the weight carried by the structure, on the weight that is super imposed on it. Loose Housing - a management system for dairy cattle wherein the adult animals are given access to a feeding area, a resting area, and an adjoining open lot. Malleability - is the material's susceptibility to extreme deformation in rolling or hammering. The more malleable the metal, the thinner the sheet into which ft can be formed. Mechanical Anchorage - any mechanical device capable of developing the strength of the reinforcement without damage to the concrete. It is the means by which the pre-stress force is permanently transferred to the concrete. Modulus of Elasticity - is the ratio of the increment of unit stress to increment of unit deformation. It is a measure of stiffness of materials. Modulus of Rupture - is the measure of the resistance of materials to bending stresses. Moment of Inertia - is the sum of the products obtained by multiplying all the infinitely small areas by the square of their distances to the neutral axis Neutral Surface - is a horizontal plane separating the compressive and tensile stresses. Panel - the portion of a truss that occurs between two adjacent joints of the upper chord. Pedestal - an upright compression member having a ratio of unsupported height to average least lateral dimension of 3 or less. Pitch - the height or rise of a truss divided by the span. Plastic Bending - bending of a material beyond the elastic range of strain. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 29 Plasticity - is the ability of a metal to be deformed considerably without rupture. Poisson's Ratio - is the ratio of the lateral strain (contracting) to the longitudinal strain (extension) when the element is loaded with a longitudinal tensile force. Polar Moment of Inertia - the moment of inertia for an area relative to a line or axis perpendicular to the plane of the area Pre-Cast Concrete - a plain or reinforced concrete element cast in other than its final position in the structure. Precipitation Heat Treatment - brings about the precipitation of a constituent from a supersaturated solid solution by holding body at an elevated temperature, also called artificial aging. Proof Stress - is that stress which causes a specified permanent deformation of a material, usually 0.01% or less. Purlin - is a beam spanning from truss to truss that brings to the trusses the leads due to wind, and weight of the roof connections. Radius of Gyration - it is an index of the stiffness of a structural section when used as a column or other compression member. Red Shortness - is brittleness in steel when it is red hot. Reinforced Concrete - concrete containing reinforcement, including pre-stressing steel, and designed on the assumption that the two materials not together in resisting forces. Relaxation - associated with creep, is the decreasing stress at a constant strain; important for metals in high temperature service. Residual Stress - are those not due to applied loads or temperature gradients, they exists for various reasons, as unequal cooling rates, cold working, etc. Resilience - the quality of absorbing impact loads without passing the elastic limit. Resistance to Corrosion - the degree to which a material resists chemical combination with other materials with which it comes in contact, is a measure of its resistance to corrosion. Rise- The height of flight of stairs from landing to landing or the height between successive treads or stairs Riser – the vertical face of a stair step Run – the horizontal distance from the first to the last riser of a stair flight Scaffolding- temporary structure of wooden poles and planks providing platform for working men to stand on while erecting or repairing a building Section Modulus - it is the measure of the strength of a beam according to the arrangement of the material. Shape Factor - is the ration of plastic section modulus to the elastic section modulus. Shear Diagram - is a graphical representation of the values of the vertical shear throughout the length of a beam. Shearing Stress - are those tending to cause two contiguous parts of a body to slide, relative to each other in a direction parallel to their plane of contact. Slenderness Ratio - the unbraced length in inches divided by the dimension of the least side. Spiral - continuously around reinforcement in the form of cylindrical helix. Staging – a more substantial framework progressively built up as tall building rises up Staircase – whole set of stairs, the structure containing a flight of a stair Stall Barn - a structure, sometimes referred to as a stanchion barn for sheltering dairy cattle and/or young stack where the adult animals are confined to one or more rows of stall by means of stanchions, straps for part of the year. Step- a stair which consists of one tread and one riser Steps – assembly consisting of a tread and a riser Stiffness - is the ability to resist deformation. It is measured by the modulus of elasticity in the elastic range, the higher the modules the stiffer Stirrup- is the structural reinforcing member that holds or binds together the main reinforcement of a beam or girder to a designed position Strain - is a change in form produced by a stress. Strain Hardening - is increasing the hardness and strength by plastic deformation. Stress - the resistance offered by a rigid body to an external force tending to change its form. Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 30 Stress Relieving - is the heating of a metal body to a suitable temperature and holding it at that temperature for a suitable time for the purpose of reducing interval residual stress. Stringer – inclined plane that supports or holds the tread and the riser of a stair Temper - is a condition produced in a non-ferrous metal by mechanical or thermal treatment: for example, annealed temper (soft), hard temper, spring temper. Tensile Stresses - are those tending to pull an object in two, or to stretch it. Toughness - the term toughness applies to the capacity of a material to resist fracture under impact loading. Tread – horizontal part of a step including the nosing Truss - is a jointed frame, used to support loads over a relatively long span. Bays - these are the spaces between trusses. Ultimate Strength - it is the unit stress occurring when a material is carrying its maximum load; the amount of stress which produces failure by increasing the unit stress until breakage or rupture occurs. Uniformly Distributed Load - is a load of uniform magnitude, for each unit of length, that extends, over a portion or the entire length of a member. Unit Stress - is the internal resistance per unit area that results from an external force Vertical Shear - the tendency for one part of a beam to move vertically with respect to an adjacent part is called. Wall - a vertical element used primarily to enclose or separate spaces. Wind Break- several rows of trees of various sizes to reduce air velocities and dust. Workability - this characteristic of a material measures the ease with which it can be worked or shaped. Working Stress/Allowable Unit Stress - the highest unit stress to which a material should be subject for a specific purpose. Wrought Alloy Steel - is steel that contains significant quantities of recognized alloying metals, the most common being aluminum, chromium, etc. Conversion Factors Area Moment of Inertia 1 in2 = 645.2 mm2 1 in4 = 0.4162 x 106 mm4 1 ft2 = 92.90 x 10-3 m2 1 ft4 = 8.631 x 10-3 m4 Bending Moment Stress Modulus or Volume 1 in-lb = 0.1130 N-m 1 in3 = 16.39 x 103 mm3 1 ft-lb = 1.356 N-m 1 ft3 = 28.32 x 10-3 m3 1 ft-kips = 1.356 kN-m Stress and Modulus of Elasticity Loads 1 psi = 6.895 kPa 1 lb = 4.448 N 1 ksi = 6.895 MPa 1 kips or 1 k = 4.448 kN 1 psf = 47.88 Pa 1 lb/ft = 14.59 N/m 1 kips/ft = 14.59 kN/m Density 1 lb/ft3 = 0.157 kN/m3 Farm Structures PSAE Region IV – Agricultural Engineering Board Review Materials VIII - 31 IV. References ASEP.1992. National Structural Code of the Philippines. Volume I. 4th Ed. Bengtsson, L.P and J.H. Whitaker.1988. Farm Structures in Tropical Climates.FAO.Rome Breyer, D.E. 1988. Design of Wood Structures. 2nd Ed. Mc Graw Hill, Inc. USA. Fajardo,Jr. , M.J.1993. Simplified Methods on Building Construction. 2nd Ed. 5138 Merchandising. Philippines. Gillesania, D.I.T. 2001. Structural Engineering and Construction for Civil Engineer Licensure Exams. Revised Edition. GPP Gillesania Printing Press. Ormoc City, Leyte, Philippines. Gray, H.E. 1955. Farm Service Buildings. McGraww-Hill Book Company, Inc. USA. Parker, Harry. 1979. Simplified Design of Structural Wood. 3rd Ed. John Wiley & Sons, Inc. Canada. Parker, Harry. 1984. Simplified Design of Reinforced Concrete. 5th Ed. John Wiley & Sons, Inc. Canada. Tamolang, F.B., E.B. Espiloy, and A.R. Floresca. 1995. Strength Grouping of Philippine Timbers for Various Uses. FPRDI Trade Bulletin Series No. 4. FPRDI, College, Laguna Tolarba, R.N. 1998. Construction Estimate Made Easy. S.A. Mendoza Publishing, Inc.Quezon City, Phipippines. Farm Structures