BDCS reading

heel

lower, supporting end of a truss

STANDING SEAM

a metal roofing seam in which adjacent sheets of material are turned up and folded over

when a square plate goes more rectangular what happens

a plate should be square or nearly quare to ensure it behaves as a 2 way structure. as a plate becomes more rectangular than square, the two way action decreases and a one way system spanning the shorter direction develops because the shorter plate s trips are stiffer and carry a greater proportion of the load

hinged frame

a rigid frame cnnected to its supports with pin joints. the pin joints prevent high bending stresses from developing by allowing the frame to rotate as a unit wen strained by support settlement, and to flex slightly when stressed by change in temp

fixed frame

a rigid frame connected to its supports with fixed joints. a fixed frame is more resistant to deflection than a hinged frame but also more sensitive to support settlements and thermal expansion and contraction

REGLET

a slot in which roofing material or flashing is inserted, generally in a vertical wall surface

rigid frame

a steel or reinforced concrete frame with rigid joints capable of resisting changes in angular relationships. least efficient of rigid, shear, and braced rames. however, rigid frames can be useful when employing braced frames or shear walls would form undesired barriers between adjacent spces

when a change in the nomical size of a column occurs

a thic butt plate welded to both sections is used to transfer the load

braced frame

a timber or steel frame braced with diagonal members

shear wall

a wood, oncrete, or masonry wall capable of resisting changes in shape and transferring lateral loads to the ground foundation. lateral forces are more citical in short direction of rectangular buildings, and shear walls or braced rames are used for this direction.

metal ties in cavity wals

adjustable loop tie, ladder loop tie with drip to prevent water from runing across to inner wythe. 3/6" min D tie of corrosion resistant metal for each 4.5 sf of wall area for cavities up to 3". for wider cavities provide a metal tie for ever 3 sf. stagger ties in alt courses w a max vertical distance between ties of 16" and max horizontal spacing of 36". place additional ties 3' oc max around openingw within 12" of the edge of the openings. 5/8" min mortar cover for joint reinforcment. see BCI 5.17

wood foundation wall

all wood and plywood used to fabricate a foundation system mustbe pressure treated with a preservative approved for ground contract use; all field cuts should be treated with the same preservative. all metal fasteners should be stainless steel or hot dipped zinc coated steel

wood wall stud sizes

2 x 4 has max unsuported height of 14' and 16" oc except when supporting only a ceiling and roof 2 x4 studs not more than 10 high and spaced 24 " oc 2 x 6 max unsupported ht of 20'. spaced 24" oc except when supporting 2 stories and a roof space 2 x 6 studs not more than 16" oc

concrete has a min compressive strength of

2500 psi

COFFERDAM

A watertight, temporary wall or enclosure, often used underwater to allow construction work to be performed on a dry site.

QUOINS

A cornerstone used at the exterior angles of a building to visually indicate strength.

PARGE

A parge coat is a thin coat of a cementitious or polymeric mortar applied to concrete or masonry for refinement of the surface. The typical parge coat is 1/4"-1/2" in thickness; this may be less than the minimum thickness allowed by many mortar types.

Capillary action with small pore materials

A porous solid will generally absorb water by capillarity, the absorptive forces beinggreater for smaller pores. In addition, water disperses more readily from larger poresin which ventilation is obviously more efficient. For these reasons small pored ormicroporous materials are likely to absorb water more strongly and to disperse itsubsequently less efficiently; they are therefore more likely to have a high moisturecontent during freezing conditions and thus more likely to suffer frost damage

BASE SHOE

A quarter round trim piece used to cover the joint between the finish flooring and the base

JACK RAFTER

A short rafter between hip rafter and eave or between valley and ridge

BOND STONE

A stone with its longest dimension perpendicular to the wall face to tie the wall to its backing. BOND BEAM : A horizontally reinforced concrete or concrete masonry beam built to strengthen and tie a masonry wall together. A bond beam is often placed at the top of a masonry wall with continuous reinforcing around the entire perimeter.

COUNTER-FLASHING

A strip of impervious material that is fastened at one edge and turned down at the other edge over flashing, to prevent water penetration at flashed joints

concrete made with high aluminacemen

Although the residual effects of calcium chloridemisuse probably accounts for most failures in structural concrete, failures due tothe use of high alumina cement certainly generated much greater publicity; in humidatmospheres, such as roofs of swimming pools, concrete made with high aluminacement can suffer serious loss of strength

if contact with dissimilar metals cannot be avoided

If contact cannot be avoided, the adjacent surfaces should be painted with bituminous or zinc chromate primers or paints. Taping or gasketing with non-absorptive materials is also effective.

Dew or surface condensation will develop on

Dew or surface condensation will develop on internal surfacesif their temperatures are below the dew point for the accommodation air; the surfacetemperatures will depend on the interior and exterior air temperatures in relation tothe thermal properties of the roof, wall, window or door structure involved

two types of diaphragms

Diaphragms are usually constructed of plywood or oriented strand board in timber construction; metal deck or composite metal deck in steel construction; or a concrete slab in concrete construction. The two primary types of diaphragm are flexible and rigid. Flexible diaphragms resist lateral forces depending on the tributary area, irrespective of the flexibility of the members that they are transferring force to. On the other hand, rigid diaphragms transfer load to frames or shear walls depending on their flexibility and their location in the structure. The flexibility of a diaphragm affects the distribution of lateral forces to the vertical components of the lateral force resisting elements in a structure

Icynene (Low Density) (sprayed)

Good for retrofitting

XPS + and -

High R-value High compressive strength High resistance to water absorption Ozone-depleting Expensive

Sprayed Polyurethane (Close Cell, High Density) +-

High R-value ozone depleating

High densityalso means

High densityalso means high thermal conductivity and such dense materials must be avoidedwhere thermal insulation is required. In addition, high density is often associatedwith microporosity and susceptibility to crystallisation damageso that very dense materials are usually avoided for general building purposes.However, lower density materials are also more porous, and if they are able toabsorb excessive amounts of water their density increases, as well as their thermalconductivity; the advantages of these lower density materials are often lost if theysuffer excessive water absorption

making beams more efficient

double the depth not he width. the depth is where they will have the most bending stress

"the perfect wall"

In concept the perfect wall has the rainwater control layer, the air control layer, the vapor control layer and the thermal control layer on the exterior of the structure. The claddings function is principally to act a an ultra-violet screen. the best place to control this air thing is on the outside of the structure—but under the insulation layer so the air does not change temperature.

sealants that corrode copper

In general, butyl, polysulfide and polyurethane sealants are reasonably compatible with copper. Acrylic, neoprene and nitrile-based sealants actively corrode copper. Silicone sealants have a variety of success with copper, but their suitability should be verified with the manufacturer. Most copper will outlast sealants - you must have regular maintenance

Warm roof vs cold roof insulation

In timber roofs it ispossible to construct a normal 'cold' roof, that is a roof in which the main insulationis on the ceiling and there is a cold ventilated space above the insulation. Thealternative is a 'warm' roof in which the main insulation is on the roof deck,immediately beneath the external roof covering. In a warm roof, interstitialcondensation within the insulation is inevitable, unless warm humid air from theaccommodation is prevented from diffusing into the insulation by provision of areliable vapour barrier on the warm side of the insulation. It is virtually impossibleto provide a sufficiently reliable vapour barrier at ceiling level, as there is always adanger that air can diffuse round the edges of the barrier and that electricians willdamage the barrier when installing light fittings. A far more reliable arrangement isto provide the vapour barrier on the roof deck

Moisture content variations v thermal variation

Moisture content variations are the usual cause of movement in structuralmaterials, such as concrete, masonry and wood, but only thermal movement issignificant with metals. Steel beams and lintels are not often the cause of differentialmovement problems in masonry, but metals subject to extremes of temperature oftencause problems.

Sprayed Polyurethane (Open Cell, Low Density) +-

Not Ozone-depleting low r value

EPS+-

Not ozone-depleting Flexible high embodied energy

Polyurethane +-

Not ozone-depleting High R-value expensive

Polyiso + -

Not ozone-depleting Recycled content High embodied energy

CORBEL

Projection of brick jutting out from a wall to support a structure above it

SCUPPER

SCUPPER : an opening in a wall or parapet for the drainage of rainwater from a roof

Subsidence

Subsidence is settlement resulting from factors other than simple compression of the supporting ground. The most dramatic subsidence results from mining and othertunnelling operations beneath a building, as well as erosion of the supporting grounddue to water movement, due either to natural water flow or leaking water mainsor drains, the latter often causing local subsidence of, for example, the corner of abuilding. However, subsidence can also occur through the building itself interferingwith the ground conditions, particularly on shrinkable clay where the building andits drainage system will reduce rain penetration into the soil which will dry outand shrink as a result.

The combustibility of largewood components

The combustibility of largewood components, such as beams, does not usually contribute significantly to afire; it is the furnishings and other components in a building that represent the mainfire risk and contribution to fire damage. Wood is actuallyvery durable in a fire because its thermal insulation properties ensure a slow firepenetration rate and continuing structural integrity.

why does copper change color

The natural weathering of copper is a direct consequence of the corrosive attack of airborne sulfur compounds. This leads to a gradual change in the surface color until equilibrium is reached and the change is stabilized. The final color is different and depends on the location and local weather. Salt, moisture, sunlight and orientation can effect the final color. In general, copper changes in hue from a natural salmon through a progression of russet browns, grays and finally to a blue-green or gray-green patina.

The simplest form of chemical damage in non metalitc materials

The simplest form of chemical damage is rainwater leaching of soluble materials.Most structural materials have excellent resistance to leaching, although occasionally rainwater leaching problems arise, usually on statuary rather than on structural components, where alabaster (gypsum or calcium sulphate) or stones containing magnesium carbonate have been used; both these compounds are appreciably soluble in rainwater.

The intensity of the damage is much greater in polluted urban atmospheres. - name some poluutants

Themost common pollutants are oxides of nitrogen, particularly associated with coal combustion, and oxides of sulphur, associated with both coal and oil combustion.The normal oxides in the atmosphere are nitrous oxide and sulphurous oxide, which dissolve in rainwater to form nitrous and sulphurous acids which react withcarbonates to form nitrites and sulphites respectively. Nitric and sulphuric acids can cause rapid erosion of carbonate and even slowerosion of silica components in stone, mortar and concrete.

RUSTICATION STRIPS

When removed, shows a deep reveal in the concrete. A form of articulated construction joint

Concrete and masonry bearing walls

Wualitfy as non combustible and rely on their mass for load carrying cabilility. strong in compression, rquire reinforcing for tensile.

when to provide horizontal reinforcement in cmu

at top of parapet walls at structurally connected floors and roofs at wall openings at top of foundations 10' max spacing vertical reinforcement 3/8" d min with max spacing of 4' oc.

t type cantilevered wall l type centilevered wall

cantilevered walls of reinforced concrete are used for retaining walls up to 20 ' high. above this height, counterforts walls are employed l type is used when the wall abuts a property line or other obstruction

bending stresses

combinaion of compressive and tensile stresses developed at a cross section of a structural member to resist a transverse force, having a max vlue at the surface furthest from the neutral axis

FLITCH BEAM

combines wood and steel into one member. Also called sandwich beam.

groin or cross vaults

compound vaults formed by the perpendicular intersection of two vaults, forming arched diagonal arrises called groins

Structural frames

concrete frames: typ rigid frames - noncombustible, fire resistive construction Noncombustible steel frames: moment connections, require fireproofing for fire resistive construction Timber frames: require diagonal bracing or shear planes for lateral stability and may qualitfy as heavy timber if used with noncombustible fire resistive exterior walls and if the members meet the min size requirement Steel and concrete frames are able to span greater distances and carry haevier loads than timber structures Structural frames can support and accept a variety of nonbearing or curtain wall systems Detailing of connections is critical for structural and visual reasons when frames are exposed

how does consolidation occur in different soils

consolidation is slight and occurs quickly in granular like coarse sand and gravel. when foundation soil is moise, cohesive clay which has a scale like structure and relatively large percentage of voids, consolidation can be quite large and occur slowly over a period of time

concrete foundation wall

foundation walls provide support for the super structure above and enclose a basement or crawl space partialy or wholly below grade. extend foundation wall at least 6" above finishg rade when supporting wood construction. slope finish grade to drain surface water from rain or melting snow away from the foundation; 5% min.

Dry rot fungus

fungal infections will only developif the wood moisture content exceeds about 22%, the type of fungal infection depending on the moisture content and wood species. If fungal infection has developed,however, and the moisture content has since declined, the Dry rot fungus can survive by producing moisture through the digestion of the affected wood, so that areas of higher moisture content may be an indication of Dry rot activity in an otherwise dry building. This situation arises typically in buildings which have been subjected to high moisture contents through leaks or indeed the processes of new construction, andwhere restricted ventilation has resulted in very slow drying through the criticalmoisture content of about 25% at which Dry rot spores germinate and develop

Gravity wall

gravity retaining wall resists overturnin gand sliding by the sheer weight and volume of its mass. gravity walls may be used for structures less than 10'

lagging

heavy timber planks joined together side by side to retain face of excavation soldier piles or beams are steel H sections driven vertically into the ground to support horizontl lagging sheet piling and soldier beams with laggings are supported with continuous horizontal wales braced by horizontal steel crossbracicng or by diagonal steel rakers bearing on heel blocks or foodtings

micropiles

high cpacity, small diameter (5"-12"), drilled grouted in place piles that are typically reuinforced. often used for foundation in urbanized areas or in locations with restricted access and for underpinning or emergency repairs because they can be installed in virtually any ground condition with minimul vibration and disturbance to existing conditions

Chloride in reinforced concrete

is also a problem in reinforced concrete as itencourages the rusting of steel reinforcement which swells and fractures the concrete. The presence of chloride will exaggerate the rateof corrosion; whilst chloride may be derived from natural sources such as sea spray,most problems are associated with the excessive use in the past of calcium chlorideas a concrete curing accelerator

if we fill in the plane defined by two columns and a beam it becomes a

load bearing wall that acts as a long, thin column in transmitting compressive forces to the ground. load bearing walls are more effective when coplaner, uniformly distributed. most vulnerable to forces perpendicular to their planes. for lateral stability rely on buttressing with pilasters, cross walls, transverse rigid frames, or horizontal slabs

The difference between malleability and ductility

malleability is the ability to deform easily upon the application of a compressive force, and ductility is doing the same with tensile force In material science, ductility specifically refers to a material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar concept, refers to a material's ability to deform under compressive stress; this is often characterized by the material's ability to form a thin sheet by hammering or rolling. Ductility and malleability do not always correlate with each other; for instance, gold is both ductile and malleable, but lead is only malleable. "

Which insulation is the least effective

mineral wool, polyurethane foam is more effective. Whenthe insulation is incorporated in new buildings as thick sheets or bats, the sheets arenot usually as thick as the cavity and are secured to the inner leaf, leaving a narrowcavity between the insulation and the outer leaf, slightly reducing the thermal insulationbut keeping it within the necessary limits, and also largely avoiding the moisturepenetration problems that can arise when the cavity is fully filled with insulation

load bearing walls leads to the use of what type of spanning system

one way because load bearing walls are most effective when supporting a uniformly distributed load, typically support a series of joists, planks, or one way slab. one way = rectangular. two way = square

what type of mortar is permitted in unreinforced masonry walls

only type m or s

how to orient steel columns

orient the webs of coumns parallel to the short axis of the structural frame or the irection along which the structure is =is most suseptible to lateral forces. orient the flanges on perimeter columns to the outside to facilitate attachment of curtain wall to the frame.

stud wall sheating

rated panel sheating: for use as a nailable base or exterior siding, 1/8" joints, stagger joints gyp sheating: exterior siding must be nailed to stud frame because gyp is not a ailable base . stagger joints fiber board sheating: high density panels may be used s a nailable base for exterior siding. stagger joints. rigid foam plastic sheating: rigid insulatin may extend below grade to insulate crawl space, must nail directly to stud frame, because the foam plastic is an effective vapor barrier, the wall assembly must be properly vented. cannot be used as corer bracing, use steel strap or 1x4 let into studs. protect exposed edgs with plywood or stucco

batter

refers to backward sloping face of a wall as it rises, which can ofset the illusion of face leaning forward

American institute of steel connection type 1

rigid frame - moment connections. connections are able to hold their original angle under loading by developing a specified resisting moment, usually by means of plates welded or bolted to the beam flanges and the supporting oclumn. small openings ok, large weaken web in shear and require stiffening or reinforcement stigner plates welded to column beam welded to stiffner plates and bolted to tab shear bolts, backing bar, stiffner top and bottom flanges welded to column,

diaphragm

s a structural system used to transfer lateral loads to shear walls or frames primarily through in-plane shear stress. These lateral loads are usually wind and earthquake loads, but other lateral loads such as lateral earth pressure or hydrostatic pressure can also be resisted by diaphragm action. The diaphragm of a structure often does double duty as the floor system or roof system in a building, or the deck of a bridge, which simultaneously supports gravity loads.

American institute of steel connection type 3

semi rigid frame - connections assume beam and girder connections posses a limited but nown moment resisting capacity all welded connections are aesthetically pleasing but expensive end plate welded to beam all around and bolted to colum

American institute of steel connection type 2

shear connection - simple frame - made to resist only shear and are free to rotate under gravity loads. shear walls or diagonal bracing is required for lateral stability of the frame. a framed connection is a shear resisting steel connedtion made my welding or bolting the web o the beam to the supporting column or girder with two angles or a single tab plate. a seated connectioni s a shear resisting steel connection made by welding or bolting flanges of a beam to the supporting column with a seat angle below and stabilizing angle above.

space frame

short rigid linear elements triangulated into 3d and subject to only axial tension or compression. supporting bays should be square as it is analgous to the two way.

column failure

short, thick columns are subject to failure by crushing rather than by buckling. the direct stress exceed the compressive strength. (kern area is the central area of any horizontal section of a column or wall within which the resultant of all compressive loads must pass, beyond this causes tensile strength) long slender columns subject to buckling rather than crushing.

RADIANT BARRIER

single sheet of highly reflective material, usually aluminum, that faces an open airspace REFLECTIVE INSULATION : A radiant barrier combined with a backing of insulation

rock caisson

socketed caissons that have a steel h section within a concrete filled pipe casing

static v dynamic loads

static loads are applied slowly to structure unti lits peak value is reached withut fluctuating rapidly in magnitude. live loads - furniture, people, snow, impact load (short duration of knetic load due to moving vehicles, equipment, machinery). dynamic - applied suddely to structure . wind and earthquake are the main two

story ht wall panels vs spanedrel wall panel support

story ht wall panels may be suspended from the floor above. alternatively they may be supported on the floor below. spandrel wall units are supported at one floor only. for stability, they are braced either below the floor or above the floor.

structural facing tile

structural clay tile having a glazed surface and used for facing walls and partitions, especially in areas subject to heavy wear, misture problems, and strict sanitation requirements. FTS: structural facing tiel suitable for exposed exterior adn interior masonry walls and partitions where moderate absorption, slight variation in face dimensions, minor defects in surface finish and medium color range. FTX: smooth structural facing tile suitable for exposed exterior and interior masonry walls and partitions hwere low absorption and stain resistance are required. high degree of mechanical perfection, mnimal vatiation in dimensions and narrow color range.

Metal and wood stu dwalls

studs of cold formed metal or wood are spaced 16" - 24" oc. related to widths of common sheating materials.studs arry vertical loads while sheathing or diagonal braces stiffens planes of walls

structural clay tile

sturctural clay tile is hollow tile of fired clay having parallel cells or cores and used in construcing walls and partition. LB grade: load bearing structural tile suitable for masonry walls not exposed to frost action or in exposed masonry where protected by a facing of 3" or more of stone, brick, terra cotta or other LBX: load beaing structural clay tile suitable for masonry exposed to weathing or frost action

surcharge

surchard is an additional load, as the earth above a retaining wall. the line of thrust parallels the slope of the surcharge. assume 33 degrees for the anngle of repose of most soils

INSULATED CONCRETE FORMS

systems of interlocking foam insulation blocks or panels that serve as forms for pouring concrete walls and that remain in place after the concrete has cured. The foam greatly increases the insulation value of the wall and serves as a backing for gypsum wallboard finish inside and sheathing and exterior finish outside

post tension members shortening

tend to shorten over time due to elastic compression, shirnkage, and creep. adjoining elements after posttentioning process is completed and be isolated from post tentioned members with expansion joints

rebar in shallow footings

tensile reinforcement is required when a spread footing projects more than half of the foundation wall thickness and is subjec tto bending there is 6" of concrete above the steel reinforcement, and 3" min netween reinforcing bars and concrete srface (bottom)

because columns in a steel frame structure transfer gravity and lateral loads down to the foundation system

the exterior walls are esentially non load bearing curtain walls. framing or panels of curtain walls may be supported by the columns alone or by columns as well as by spandrel beams or the edges of floor slabs.

the most common cause of weakening of joists and beams

the most common cause of weakening is notching of joistsand beams by thoughtless plumbers and electricians. Holes drilled at mid-depth willhave no significant effect on strength; while such holes can be used by electriciansfor cable runs, the situation is more difficult for plumbers who prefer, for obviousconvenience, to run their pipes in notches cut into the tops of joists and beams

the longest spanning systems

timber truss = 100 ' open web joists = 90' reinforced precast t's = 100' laminated beams = 80' waffle slabs = 50' steel wide flange beams = 60' two way slabs and beams= 40' reinforced concrete precast planks = 40' reinforced concrete jiost slabs = 35' 2 way flat plate = 25' one way slab = 20' timber joists = 20' steel decking = 15' timber planks - 15'

deadman

timber, stone, or concrete mass bruied in the ground as an anchor, used for walls over 3' high and placed 6' oc. used with horizontal timber retaining wall.

when is a backer plate used in steel

to make up difference in flagne thickness at a bolted connection

type VA

type v protected requires all major building elements except non bearing interior walls and paritions to be one hour fire resistive construction. type VB (unprotected) has o rquirement except when code requires exterior wall protection due to their proximity to the property line

underpinning

underpinning = rebuilding or strengthening the foundation of an existing building or extending a new foundation. 1.needle beams pass through foundation wall and carried by hydraulic jacks and shores 2. dig intermittent pits under the existing foundation downt o the level of new footings. after new foundation wall and footing section are placed, additional pits are dug until entire all has been deepend 3. an alternative to extending a new foundation wall and placing new footings is to construct piles or caissons on either side of existing foundation, removing a sectin of foundation wall and replace with a reinforced concrete pile cap

floating foundation

used in yielding soil, has its footing a mat placed deep enough that the weight of the excavated soil is equal to or greater than te weight of the construction supported

counterfort walls utilize trianglar shaped cross walls to stiffen the verical slab and add weight to the base. the counterforts are spaced at regular inteverals to one half the wall height.

utilize trianglar shaped cross walls to stiffen the verical slab and add weight to the base. the counterforts are spaced at regular inteverals to one half the wall height.

post and beam framing

utilizes a frameowrk of vertical posts and horizontal beas to carry floor and roof loads. the beams supporting the floor and roof systems transmit their loads to posts or columns that in turn carry the loads down the foundation. can be considered heavy timber if roof structures are supported by non combustible fire resistive exteriror walls and the wood members and decking meet min sizes by coe

an opening in a load bearing wall

weakens its structural integrity. a lintel or arch must support the load above a door or window to allow all compressive stresses to flow around the opening to adjacent sections of the wall

concrete beam reinforcing

web reinforment consists of bent bars or stirrups placed in a concrete beam to resist diagonal tension. bent bars are longigudinal bars bent to an angle of 30 degrees or more. stirrups are any of th u shaped or close loop bars placed perp to the longitudinal reinorcment of a concrete beam. top bars are longitudinal bars serving as tension reinforcment in the section of concrete beam subject to the upward bending of a negative moment . top beams also required when the beam depth is limited and insufficient concrete area to handle compressive stresses

when are stifeners required

when a steel column bears on a thin base plate. a seismic foundation connection utilizes sittner plates and anchor tolbs set in a concrete foundation.

Movement withfluctuations in moisture content is greatest in

wood