11 27 2012 Glass Benefits of using glass o Allows entry of natural light o Provide views of exterior environment Disadvantages and or Design Considerations Glass as a Material Major ingredient Strength Glass Thicknesses Tempered Glass Ordinary glass annealed Tempered Glass When tempered Glass Breaks Strength and breakage characteristics make it well suited for Disadvantages Laminated Glass Sandwiching PVB Uses Fire Rated Glass Required for Glass types Spandrel Glass Interior face Tinted and Reflective Glass Process Glass and building codes Ch 2 Foundations 11 27 2012 Foundation Requirements Must transmit building loads to the rock or soil on which it rest Must not fail resulting in building collapse Must not settle so much as to damage structure or impair function Must be economically and technically feasible and without adverse affects on surrounding structures Building Foundations Purpose safely transfer building loads to the ground every building has building loads therefore every building has foundations Foundation Settlement uniform settlement may disrupt building services where the enter building or damage elements such as stairs and walks at the building site interface differential settlement may cause damage to finishes cladding and other components where building becomes distorted Live load weight of building and everything inside of it Dead load structural weight of the building itself Wind load weight of wind pushing on to the house Classifying earth materials Structural properties rock to peat o Rock continuous mass of solid mineral material Generally the strongest most stable of earth materials Strength varies with mineral content and physical structure o Soil particulate Characteristics and suitability for foundation support vary with particle size and shape mineral content and sensitivity to moisture content Particle size boulders to clay o Boulder too big to lift with one hand o Cobble can be lifted in one hand o Coarse grained soils gravel sand Gravel individual particles can be lifted between thumb and fore finger Don t stick together when wet cohesionless When unconfined have little strength Structural properties little affected by moisture content Free draining best at draining water away from foundations and substructures o Fine grained soils Smaller particle size less free draining When wet may be subject to liquefaction during seismic events Drainage characteristics vary Varying degrees of cohesiveness tendency to stick together o Clays Particles so small that electrostatic forces cause particles to stick together cohesive soil Structural properties vary greatly o Organic soils Peat topsoil and other soils with organic content Generally weak unstable and not suited for support foundations Drainage water retention Soil Particle Grading Well graded soil particles of many sizes Well sorted soil limited range of particle sizes most void space most free draining Soil distribution Rarely one type often a mixture and or different strata Distribution of soil type and particle size important in predicting o Load bearing capacity o Soil stability o Drainage characteristics Excavation Every site has some amount e g organic topsoil range o very little good soil and shallow foundations to o considerable poor soil and or deep structure excavation support o sloped or benched excavation is less expensive than sheeted excavations but requires a site without nearby property lines adjacent structures or other limits on excavation slope support o deep excavations types of site conditions unrestricted site area sufficiently larger than the building footprint bench and or angle of repose must have perimeter clearance considerations o band erosion o water diversion o safety o storage and backfill most likely least expensive restricted site area not larger than building footprint types of sheeting o soldier beams and lagging o sheet piling wood steel precast o slurry wall steps layout excavate the soil interject slurry to prevent collapse as excavation continues install reinforcing place concrete replaces the slurry mix 15 pt quiz ch 1 2 up to watering t f multiple choice listing 11 27 2012 Considerations w Sump Pumps and Well Points water discharge surrounding water table draw down soil contamination migration reliability of the pumping system Watertight Barrier Walls keep water out barrier must reach an impervious strata types o slurry walls o sheeting w pumps must resist hydrostatic pressure Foundations major building parts o superstructure o substructure o foundation purpose o transfer building loads to the earth basic types o shallow transfer load base of substructure o deep penetrate unsuitable soil to reach competent soil or rock shallow foundations o requirements suitable soil bearing capacity undisturbed soil or engineered fill o basic types or configurations column footings wall or strip footings o types slab on grade crawl space basement deep foundations o where the soil directly below the building substructure are weak or unstable deep foundations transmit building loads to deeper more competent soils o basic types drilled and poured driven o caissons similar to a column footing only deeper drilled to required bearing capacity point bearing exception socketed caisson installation sequence hole drilled with a large drill rig casing installed typically bell or tip enlargement optional bottom inspected and tested reinforced concrete placement and casing removal o driven piles two basic types of piles end bearing pile point loading friction pile pile material steel h piles steel pipe concrete site cast wood pile caps for load distribution reinforced concrete cap o underpinning building superstructure is temporarily supported on cribbing while new foundations are built dampproofing and waterproofing o structures below ground subject to penetration of ground water o more extreme if below H2O table o dampproofing materials are water resistant o waterproofing materials are resistant to hydrostatic pressure drainage o drainage mat and free draining backfill material allow ground water to flow away from the substructure o perforated piping conducts water away from the substructure quiz Monday 15 pts ch 1 2 Ch 13 Concrete Construction why is concrete such an important material 11 27 2012 universal marterial of construction readily available globally good properties relatively low cost concrete properties versatile pliable when mixed strong and durable does not rust or rot does