twenty eight link to posted schedule - PowerPoint PPT Presentation

A RCHITECTURAL S TRUCTURES : Office Hours F ORM, B EHAVIOR, AND D ESIGN A RCH 331 D R. A NNE N ICHOLS S PRING 2019 lecture twenty eight link to posted schedule http://faculty.arch.tamu.edu/anichols/schedule/ masonry construction: www.theeagle.com beams & columns Masonry Construction 1 Architectural Structures F2010abn Masonry Construction 2 Architectural Structures F2012abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 Masonry Design Masonry Beam & Wall Design • Masonry Standards Joint Committee • reinforcement increases capacity & ductility – ACI, ASCE, TMS – ASD (+empirical) • linear-elastic stresses – LRFD added in 2002 – referenced by IBC – unreinforced allows tension in flexure – reinforced - all tension in steel – walls are also in compression International Masonry Institute (Brian Trimble) Masonry Construction 3 Foundations Structures F2008abn Masonry Construction 2 Foundations Structures F2008abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 1

Masonry Materials Masonry Design • units • f s is not the yield stress – stone, brick, concrete block, clay tile • f m is the stress in the masonry STRAIN STRESS  m f m C m =f m b(kd)/2 kd d n.a. jd M t  s f s /n T s =A s f s A s grout unit A s   bd www.GlenGerybrick.com BIA Teknote 17 series National Concrete Masonry Association Masonry Construction 4 Foundations Structures F2008abn Masonry Construction 5 Foundations Structures F2008abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 Masonry Materials Masonry Materials • mortar • rebar – water, • grout masonry cement, – fills voids and fixes rebar sand, lime • prisms – types: – used to test strength, Ryan-Briggs Associates • M higher strength – 2500 psi (ave.) National Concrete Masonry Association f  m A • S medium high strength – 1800 psi O • fire resistant • N medium strength – 750 psi W • O medium low strength – 350 psi R • K low strength – 75 psi National Concrete Masonry Association Masonry Construction 6 Foundations Structures F2008abn Masonry Construction 7 Foundations Structures F2008abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 2

Masonry Materials Allowable Masonry Stresses • moisture resistance • tension - unreinforced only – weathering index for brick – bond and detailing – expansion or shrinking from water • provide control joints • parapets, corners, long walls parapet with no control joint Masonry Construction 8 Foundations Structures F2008abn Masonry Construction 9 Foundations Structures F2008abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 Allowable Masonry Stresses Masonry Walls • flexure tension normal to bed joints WALLS – F b = 1/3 f’ m (unreinforced) – F b = 0.45 f’ m (reinforced) Not allowed in MSJC code • shear, unreinforced masonry f   120 psi – F v = 1.5 m tension parallel to bed joints • shear, reinforced masonry f  – M/Vd  0.25: F v = 3.0 m f  – M/Vd  1.0: F v = 2.0 m weak units strong units Masonry Construction 11 Architectural Structures F2008abn Lecture 28 ARCH 331 Masonry Construction 10 Foundations Structures F2008abn Lecture 28 ARCH 331 3

Allowable Reinforcement Stress Reinforcement, M s • tension C m =f m b(kd)/2 kd a) Grade 40 or 50 F s = 20 ksi d n.a. jd b) Grade 60 F s = 32 ksi t T s =A s f s A s c) Wire joint F s = 30 ksi grout kd   F=0: A f f b unit s s m 2 • *no allowed increase by 1/3 for   ρbd 2 M A f jd jf  M about C m : s s s s combinations with wind & earthquake if f s =F s (allowable) the moment capacity is limited by the steel – did before 2011 MSJC code MSJC: F s = 20 ksi, 24 ksi or 30 ksi by type Masonry Construction 12 Foundations Structures F2008abn Masonry Construction 14 Architectural Structures III F2010abn Lecture 28 ARCH 331 Lecture 23 ARCH 631 Reinforcement, M m Masonry Lintels • distributed load C m =f m b(kd)/2 kd – triangular or trapezoidal d n.a. jd t T s =A s f s A s grout kd   F=0: A f f b unit s s m 2 kd   2  M about T M f b jd 0 . 5 f bd jk s : m m m 2 if f s =F s (allowable) the moment capacity is limited by the steel MSJC F b =0.33f’ m Masonry Construction 16 Foundations Structures F2010abn Masonry Construction 15 Architectural Structures III F2010abn Lecture 23 ARCH 631 Lecture 28 ARCH 331 4

Strategy for RM Flexural Design Ultimate Strength Design • to size section and find reinforcement • LRFD – find  b knowing f ’ m and f y • like reinforced concrete – size section for some  <  b • useful when beam shear is high • get k, j M • improved inelastic  2 • needs to be sized bd   0.80 f ’ m c jF for shear also 1 model s • get b & d in nice units 2 C M – ex. earthquake loads s   1 c – size reinforcement (bar size & #): A F jd   – check design: s M A F jd M s s s T M   f F b b 2 0 . 5 bd jk Masonry Construction 15 Foundations Structures F2008abn Lecture 28 ARCH 331 Masonry Construction 16 Foundations Structures F2008abn Lecture 28 ARCH 331 Masonry Columns and Pilasters Masonry Columns and Pilasters • must be reinforced • considered a column when b/t<3 and h/t>4 • b is width of “ wall ” • t is thickness of “ wall ” • slender is – 8 ” one side – h/t  25 • needs ties • eccentricity may be required Masonry Construction 17 Foundations Structures F2008abn Masonry Construction 18 Foundations Structures F2008abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 5

Masonry Columns Masonry Walls (unreinforced) – allowable axial load – allowable axial stresses   2     h       2 2         70 P 0 . 25 f A 0 . 65 A F 1 r h          a m n st s     F 0 . 25 f 0 25 1   F . f 140 r   h/r  99 a m a m      140  h r   2   h/r  99 h/r > 99   70 r      P 0 . 25 f A 0 . 65 A F a m n st s   h h/r > 99 h = effective length r = radius of gyration A n = effective area of masonry A st = effective area of column reinforcement F s = allowable compressive stress in column reinforcement Masonry Construction 21 Foundations Structures F2011abn Masonry Construction 20 Foundations Structures F2008abn Lecture 24 ARCH 331 Lecture 28 ARCH 331 Design Design • masonry columns and walls • masonry columns and walls - loading (unreinforced) – wind loading P f f     e w a b 1 . 0 f f F – eccentric axial load and b a t F F – “ virtual ” eccentricity, e 1 a b h   2   h      P – h/r < 99   0 25 1 P F . f e o e o w w a m    140  r   2   70 r     – h/r > 99 0 25 F . f M e  a m   h 1 P V V  M  e 1 F 0 . 33 f virtual eccentricity b m P P Masonry Construction 22 Foundations Structures F2008abn Masonry Construction 21 Foundations Structures F2008abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 6

Design Design Steps Knowing Loads • masonry columns and walls – with rebar 1. assume limiting stress • – wall reinforcement usually at center and ineffective buckling, axial stress, combined stress in compression   f  f f F F 2. solve for r, A or S provided a b b a a BENDING STRESS AXIAL STRESS 3. pick trial section f m C m =f m b(kd)/2 f a = P/A 4. analyze stresses d n.a. jd M t 5. section ok? f s /n T s =A s f s A s grout unit 6. stop when section is ok     F P C T for equilibrium: m s Masonry Construction 23 Foundations Structures F2008abn Lecture 28 ARCH 331 Masonry Construction 24 Foundations Structures F2008abn Lecture 28 ARCH 331 Final Exam Material Final Exam Material • my list: • my list (continued): – systems – beams • components & levels • distributed loads, tributary width, V&M, stresses, design, section properties ( I & S), • design considerations pitch, deflection – equilibrium -  F &  M – columns • supports, trusses, cables, beams, pinned frames, • stresses, design, section properties ( I & r) rigid frames – frames – materials • P, V & M, P-  , effective length with joint • strain & stress (E), temperature, constraints stiffness, connection design, tension member design Masonry Construction 26 Foundations Structures F2008abn Masonry Construction 27 Foundations Structures F2008abn Lecture 28 ARCH 331 Lecture 28 ARCH 331 7

Final Exam Material • my list (continued): – foundations • types • sizing & structural design • overturning and sliding – design specifics • steel (ASD & LRFD) • concrete • wood • masonry Masonry Construction 28 Foundations Structures F2008abn Lecture 28 ARCH 331 8